City: PICKENS
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION
Site Information:
Address:
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION
PICKENS, SC
EPA ID:
EPA Region:
SCD003354412
04
Site Name:
Site Alias Name(s):
SANGAMO/TWELVE-MILE/HARTWELL PCB
SANGAMO WESTON-PICKENS PLANT
HAYWOOD RESERVOIR
MIDWAY LANDFILL
CROSS ROADS CHURCH
BREZEAL PROPERTY
WELLBORN PROPERTY
MAW BRIDGE ROAD
NIX, ERNEST PROPERTY
SANGAMO ELECTRIC
SANGAMO PROPERTY
SANGAMO WESTON/TWELVE-MILE/HARTWELL PCB
Record of Decision (ROD):
ROD Date:
Operable Unit:
ROD ID:
12/19/1990
01
EPA/ROD/R04-91/100
Media:
SOIL SLUDGE DEBRIS GROUND WATER
Contaminant:
VOCS, PCE, TCE, OTHER ORGANICS, PCBS
Abstract:
THE 253-ACRE SANGAMO/TWELVE-MILE/HARTWELL PCB
SITE CONSISTS OF SEVEN SEPARATE DISPOSAL AREAS IN
PICKENS COUNTY, SOUTH CAROLINA. THESE AREAS
CONSIST OF THE SANGAMO PLANT AREA AND SIX
PRIVATE DISPOSAL AREAS LOCATED OFFSITE OF THE
SANGAMO PLANT, WHICH ARE DESIGNATED AS THE
BREAZEALE, NIX, DODGENS, CROSS ROADS, JOHN
TROTTER, AND WELBORN AREAS. LAND IN THE GENERAL
AREA IS PREDOMINANTLY FORESTED, AND THERE ARE
SEVERAL NEARBY LAKES AND STREAMS INCLUDING
LAKE HARTWELL AND THE TWELVE-MILE CREEK BASIN.
SINCE 1955, SANGAMO WESTON, INC., HAS
MANUFACTURED ELECTROLYTIC, MICA, AND POWER
FACTOR CAPACITORS. PCBS WERE USED AS DIELECTRIC
FLUID IN POWER FACTOR CAPACITORS. PRIOR TO 1972,
WASTE MATERIALS CONTAINING PCBS WERE
LANDFILLED IN THE SEVEN DISPOSAL AREAS. THESE
PCB-CONTAMINATED MATERIALS INCLUDED SCRAP
CAPACITORS AND ALUMINUM HYDROXIDE SLUDGE
FROM AN ONSITE WASTEWATER TREATMENT PLANT. IN
THE MID-1970'S, STATE AND FEDERAL ENVIRONMENTAL
MONITORING PROGRAMS LED TO THE DETECTION OF
PCBS IN THE SEDIMENT OF LAKE HARTWELL, IN ITS
TRIBUTARIES, AND IN THE SOIL OF SANGAMO WESTON'S
DUMP SITES. IN ADDITION, PCBS WERE DETECTED IN FISH
SAMPLES AT TWO SITES IN THE TWELVE-MILE CREEK
AREA OF LAKE HARTWELL. IN 1980, SANGAMO WESTON,
INC., REMOVED A TOTAL OF 17,711 CUBIC YARDS OF
PCB-CONTAMINATED SOIL AND DEBRIS FROM THE NIX
AND DODGENS AREAS, AND DISPOSED OF IT IN A
LANDFILL ON THE SANGAMO PLANT PROPERTY. IN 1986,
A GEOTEXTILE LINER AND SOIL CAP WERE INSTALLED AS
AN INTERIM MEASURE TO RETARD THE MIGRATION OF
PCB CONTAMINATION FROM THE BREAZEALE SITE. IN
1989, EPA REMOVED OFFSITE 7,285 TONS OF
PCB-CONTAMINATED SOIL AND DEBRIS FROM THE
SANGAMO PLANT AREA TO A RCRA LANDFILL, AND 6,684
CAPACITORS WERE TAKEN TO AN OFFSITE INCINERATOR.
THIS RECORD OF DECISION (ROD) ADDRESSES THE FIRST
OF TWO OPERABLE UNITS, AND PROVIDES FOR
REMEDIATION OF THE GROUND WATER AND SOURCE
CONTAMINATION AT THE SEVEN DISPOSAL AREAS. A
FUTURE ROD WILL ADDRESS THE CONTAMINATION OF
THE TWELVE-MILE CREEK BASIN AND LAKE HARTWELL.
THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING
THE SOIL, SLUDGE, DEBRIS, AND GROUND WATER ARE
VOCS INCLUDING PCE AND TCE; AND OTHER ORGANICS
INCLUDING PCBS.
THE SELECTED REMEDIAL ACTION FOR THIS SITE
INCLUDES EXCAVATING MATERIALS CONTAMINATED
WITH GREATER THAN 1 MG/KG OF PCBS AT THE NIX AND
WELBORN AREAS; EXCAVATING MATERIALS
CONTAMINATED WITH GREATER THAN 25 MG/KG OF
PCBS AT THE SANGAMO PLANT AREA; EXCAVATING
MATERIALS CONTAMINATED WITH GREATER THAN 10
MG/KG OF PCBS AT THE BREAZEALE, DODGENS, CROSS
ROADS, AND JOHN TROTTER AREAS; TRANSPORTING THE
EXCAVATED MATERIALS TO THE SANGAMO PLANT AREA
FOR STAGING AND TREATMENT; TREATING ONSITE ALL
EXCAVATED MATERIALS USING THERMAL DESORPTION
TECHNOLOGY AND CARBON ADSORPTION TO CONTROL
OFF-GASES; PLACING THE TREATED SOIL WITHIN THE
PLANT AREA; FILLING EACH OF THE PRIVATE AREAS
WITH 2 FEET OF CLEAN FILL WHERE CONTAMINATED
MATERIALS WITH PCBS GREATER THAN 1 MG/KG
REMAIN, SPECIFICALLY THE TROTTER, DODGENS,
BREAZEALE, AND CROSS ROADS AREAS; GROUND WATER
PUMPING AND ONSITE TREATMENT AT THE DODGENS,
BREAZEALE, CROSS ROADS, AND SANGAMO PLANT
AREAS USING AIR STRIPPING AND/OR CARBON
ADSORPTION; AND DISCHARGING TREATED WATER
ONSITE TO SURFACE WATER. THE ESTIMATED PRESENT
WORTH COST FOR THIS REMEDIAL ACTION RANGES
FROM $47,900,000 TO $63,300,000 DEPENDING ON AQUIFER
CHARACTERISTICS AND THE VOLUME OF EXCAVATED
SOLIDS. NO O&M COSTS WERE PROVIDED FOR THIS
REMEDIAL ACTION.
PERFORMANCE STANDARDS OR GOALS;
CHEMICAL-SPECIFIC GROUND WATER CLEAN-UP GOALS
ARE BASED ON SDWA MCLS AND INCLUDE PCBS 0.0005
MG/L (PROPOSED MCL), PCE 0.005 MG/L (MCL), AND TCE
0.005 MG/L (MCL). CHEMICAL-SPECIFIC CLEAN-UP GOALS
FOR SOIL, SLUDGE, AND DEBRIS INCLUDE TREATMENT
TO A LEVEL OF PCB 2 MG/KG. SOIL WITH GREATER THAN
PCB 1 MG/KG REMAINING AT THE VARIOUS AREAS WILL
BE COVERED WITH 2 FEET OF CLEAN FILL.
Remedy:
THIS OPERABLE UNIT IS THE FIRST OF TWO THAT ARE
PLANNED FOR THE SITE. THE FIRST OPERABLE UNIT
ADDRESSES THE SANGAMO PLANT SITE AND SIX OTHER
DISPOSAL AREAS BY TREATING BOTH SOURCE AND
GROUNDWATER CONTAMINATION.
THE MAJOR COMPONENTS OF THE SELECTED REMEDY
INCLUDE;
* EXTRACTION AND TREATMENT BY AIR STRIPPING
AND/OR CARBON ADSORPTION OF CONTAMINATED
GROUNDWATER AT THE DODGENS, BREAZEALE, CROSS
ROADS AND PLANT SITES;
* DISCHARGE OF TREATED WATER TO THE NEAREST
VIABLE SURFACE WATER BODY IN ACCORDANCE WITH
APPLICABLE REGULATIONS;
* EXCAVATION OF MATERIALS CONTAMINATED WITH
GREATER THAN 1 PPM OF PCBS AT THE NIX AND
WELBORN PROPERTIES AND TRANSPORT OF THE
MATERIALS TO THE SANGAMO PLANT SITE FOR STAGING
AND APPROPRIATE TREATMENT EXCAVATION OF
MATERIALS CONTAMINATED WITH GREATER THAN 10
PPM PCBS ON THE REMAINING FOUR PRIVATE
PROPERTIES (TROTTER, DODGENS, BREAZEALE AND
CROSS ROADS) AND TRANSPORT TO THE SANGAMO
PLANT SITE FOR STAGING AND APPROPRIATE
TREATMENT;
* BACKFILL TWO FEET OF CLEAN FILL AT EACH OF THE
PRIVATE PROPERTIES WHERE CONTAMINATED
MATERIALS OF GREATER THAN 1 PPM REMAIN (TROTTER,
DODGENS, BREAZEALE AND CROSS ROADS);
* EXCAVATE MATERIAL CONTAINING GREATER THAN 25
PPM CONCENTRATION OF PCBS ON THE PLANT SITE;
* TREAT ALL EXCAVATED MATERIALS TO 2 PPM PCBS
USING THERMAL SEPARATION TECHNOLOGY ON THE
PLANT SITE. DURING REMEDIAL DESIGN, A
TREATABILITY STUDY WILL BE CONDUCTED TO
DETERMINE IF ANY OF THE CONTAMINATED MATERIALS
WILL REQUIRE ADDITIONAL TREATMENT BEYOND
THERMAL SEPARATION IN ORDER TO MEET THE 2 PPM
CRITERIA. IF NECESSARY, A ROD AMENDMENT WILL BE
COMPLETED TO ACCOUNT FOR THIS REQUIRED
TREATMENT; AND
* REPLACE REMEDIATED SOIL ON THE PLANT SITE.
Text:
Full-text ROD document follows on next page.
EPA/ROD/R04-91/100
1991
EPA Superfund
Record of Decision:
SANGAMO WESTON, INC./TWELVE-MILE
CREEK/LAKE HARTWELL PCB CONTAMINATION
EPA ID: SCD003354412
OU 01
PICKENS, SC
12/19/1990
Text:
This ROD has associated ESDs.
SITE NAME AND LOCATION
SANGAMO WESTON/TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION SITE
OPERABLE UNIT ONE
PICKENS, PICKENS COUNTY, SOUTH CAROLINA
#SBP
STATEMENT OF BASIS AND PURPOSE
THIS DECISION DOCUMENT PRESENTS THE SELECTED REMEDIAL ACTION FOR
OPERABLE UNIT ONE OF THE SANGAMO WESTON/TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION SITE IN PICKENS, SOUTH CAROLINA, CHOSEN IN ACCORDANCE
WITH CERCLA, AS AMENDED BY SARA AND, TO THE EXTENT PRACTICABLE, THE
NATIONAL CONTINGENCY PLAN. THIS DECISION IS BASED ON THE ADMINISTRATIVE
RECORD FILE FOR THIS SITE.
THE STATE OF SOUTH CAROLINA CONCURS WITH THE SELECTED REMEDY.
ASSESSMENT OF THE SITE
ACTUAL OR THREATENED RELEASES OF HAZARDOUS SUBSTANCES FROM THIS SITE, IF
NOT ADDRESSED BY IMPLEMENTING THE RESPONSE ACTION SELECTED IN THIS ROD,
MAY PRESENT AN IMMINENT AND SUBSTANTIAL ENDANGERMENT TO PUBLIC HEALTH,
WELFARE, OR THE ENVIRONMENT.
STATUTORY DETERMINATIONS
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THE SELECTED REMEDY IS PROTECTIVE OF HUMAN HEALTH AND THE ENVIRONMENT,
COMPLIES WITH FEDERAL AND STATE REQUIREMENTS THAT ARE LEGALLY APPLICABLE
OR RELEVANT AND APPROPRIATE TO THE REMEDIAL ACTION, AND IS
COST-EFFECTIVE. THIS REMEDY UTILIZES PERMANENT SOLUTIONS AND
ALTERNATIVE TREATMENT (OR RESOURCE RECOVERY) TECHNOLOGIES TO THE MAXIMUM
EXTENT PRACTICABLE AND SATISFIES THE STATUTORY PREFERENCE FOR REMEDIES
THAT EMPLOY TREATMENT THAT REDUCES TOXICITY, MOBILITY, OR VOLUME AS A
PRINCIPAL ELEMENT. BECAUSE THIS REMEDY WILL NOT RESULT IN HAZARDOUS
SUBSTANCES REMAINING ON-SITE ABOVE HEALTH-BASED LEVELS, THO FIVE-YEAR
REVIEW WILL NOT APPLY TO THE SOURCE REMEDIAL ACTION.
GREER C. TIDWELL
REGIONAL ADMINISTRATOR
DATE: DECEMBER 19, 1990
SANGAMO WESTON/TWELVE-MILE CREEK/ LAKE HARTWELL
PCB CONTAMINATION SITE
PICKENS, PICKENS COUNTY, SOUTH CAROLINA
#INT
INTRODUCTION
THE SANGAMO WESTON/TWELVE-MILE CREEK/LAKE HARTWELL PCB CONTAMINATION
SITE (SANGAMO WESTON) WAS PROPOSED FOR INCLUSION ON THE NATIONAL
PRIORITIES LIST (NPL) IN JANUARY 1987 AND WAS FINALIZED IN FEBRUARY
1990. THE SITE RANKS 553 OUT OF 1218 NPL SITES.
#SNL
1.0 SITE NAME AND LOCATION
THE SANGAMO WESTON SITE IS LOCATED IN PICKENS COUNTY, SOUTH CAROLINA
(FIGURE 1). THE ROD ADDRESSES SEVEN (7) SEPARATE DISPOSAL AREAS. FIVE
PRIVATE PROPERTIES AND THE SANGAMO PLANT SITE DISPOSAL AREAS WERE
REPORTED TO EPA BY SANGAMO IN THEIR 103(C) NOTIFICATION TO THE AGENCY.
THE PRIVATE PROPERTIES ARE; CROSS ROADS SITE, BREAZEALE SITE, DODGENS
SITE, WELBORN SITE, AND THE NIX SITE. THE JOHN TROTTER SITE, ALSO
ADDRESSED IN THIS RECORD OF DECISION, WAS DISCOVERED BY EPA DURING
SUBSEQUENT SAMPLING INVESTIGATIONS.
ALL SITES ARE SITUATED IN THE PIEDMONT PHYSIOGRAPHIC PROVINCE OF SOUTH
CAROLINA. THE PIEDMONT PROVINCE IS A BROAD PLATEAU RANGING IN ELEVATION
FROM 400 TO 1200 FEET ABOVE MEAN SEA LEVEL. THE GEOLOGY OF THE AREA
CONSISTS OF GNEISSES AND SCHISTS, INTRUDED BY IGNEOUS ROCKS, E.G.,
GRANITES. THE BEDROCK IS OVERLAIN BY A LAYER OF SAPROLITE AND SLOPE
WASH DEPOSITS, AND ALLUVIAL FILL MATERIAL OF VARIABLE THICKNESS
(OVERSTREET, 1965).
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THE PLATEAU REGION IS DISSECTED BY STREAMS WHICH HAVE DEVELOPED A
DENDRITIC DRAINAGE PATTERN. THIS DRAINAGE PATTERN IS CHARACTERIZED BY
IRREGULAR BRANCHING OF STREAMS DEVELOPED UPON MATERIALS WITH A UNIFORM
RESISTANCE TO EROSION. STREAM FLOW IN THE PROVINCE IS TO THE SOUTHEAST.
MAJOR STREAMS IN THE PROVINCE HAVE DEVELOPED IN VALLEY BOTTOMS UPON A
SAPROLITE OR SLOPE WASH DEPOSIT BASE. TRIBUTARIES FLOW FROM RIDGE AREAS
IN AN IRREGULAR PATTERN TO-THESE MAJOR STREAMS.
GROUNDWATER IN THE PIEDMONT PROVINCE OCCURS PRINCIPALLY UNDER
UNCONFINED CONDITIONS IN SAPROLITE AND SLOPE WASH DEPOSITS. GROUNDWATER
IS THE RESULT OF DIRECT INFILTRATION OF PRECIPITATION, WITH PRINCIPAL
RECHARGE AREAS IN TOPOGRAPHICALLY HIGH AREAS (RIDGE TOPS) AND DISCHARGE
AREAS NEAR STREAMS IN VALLEY BOTTOMS. THE GROUNDWATER FLOW REGIME IN
THE PIEDMONT PROVINCE IS CONTROLLED BY THE DEGREE OF RIDGE AND VALLEY
DEVELOPMENT ON THE PLATEAU AREA.
GROUNDWATER IN CRYSTALLINE ROCK IS GENERALLY RESTRICTED TO THE UPPER
ZONE OF THE BEDROCK WHERE FRACTURES AND JOINTS MOST COMMONLY OCCUR.
GROUNDWATER OCCURRENCE IN CRYSTALLINE ROCKS DECREASES WITH INCREASING
DEPTH BECAUSE JOINTS AND FRACTURES REDUCE IN SIZE AND NUMBER.
NEITHER THE SAPROLITE NOR THE ROCK ARE EXTENSIVELY USED AS WATER
SUPPLIES. MOST RESIDENCES AND INDUSTRIAL OR COMMERCIAL ENTERPRISES
WITHIN THE PIEDMONT, INCLUDING PICKENS COUNTY, OBTAIN DRINKING WATER
FROM SURFACE WATER SOURCES.
1.1 THE SANGAMO WESTON SITE
THE SANGAMO WESTON SITE IS APPROXIMATELY 220 ACRES IN SIZE AND IS
LOCATED APPROXIMATELY ONE MILE NORTHWEST OF THE TOWN OF PICKENS (FIGURE
2). BASED ON THE PRELIMINARY FIELD INVESTIGATION, THE SANGAMO WESTON
PLANT SITE HAS BEEN DIVIDED INTO TEN AREAS. THESE AREAS ARE IDENTIFIED
AS A THROUGH H, THE SEPTIC DRAIN FIELD, AND THE WASTEWATER TREATMENT
FACILITY IS EXHIBITED ON THE SANGAMO WESTON SITE WITH ELEVATIONS RANGING
FROM 930 FEET ABOVE MEAN SEA LEVEL (MSL) AT TOWN CREEK, BORDERING THE
SITE TO THE SOUTH, TO ABOUT 1,150 FEET ABOVE MSL ON THE TOP OF A LINEAR
EAST-WEST TRENDING RIDGE DISSECTING THE PROPERTY. THE MANUFACTURING
BUILDING IS LOCATED ON THE TOP OF THE RIDGE AT AN ELEVATION OF ABOUT
1,100 FEET ABOVE MSL. THE PAVED PARKING AREA FOR THE MANUFACTURING
BUILDING IS LOCATED ALONG THE SOUTH FLANK OF THE RIDGE ADJACENT TO THE
BUILDING.
THE WASTEWATER TREATMENT FACILITY, CONSISTING OF A STABILIZATION LAGOON,
AN INACTIVE EQUALIZATION BASIN AND A CONCRETE-LINED EQUALIZATION BASIN,
IS LOCATED SOUTH OF THE MANUFACTURING BUILDING. DISCHARGE FROM THE
STABILIZATION LAGOON PASSES OVER A CONCRETE SPILLWAY UNDER SANGAMO ROAD
AND THEN TO TOWN CREEK. THE DISCHARGE IS REGULATED UNDER AN NPDES
PERMIT ISSUED BY THE STATE OF SOUTH CAROLINA TO THE CURRENT OPERATOR OF
THE PLANT.
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THE RIDGE BISECTING THE SANGAMO WESTON SITE ACTS AS A DIVIDE FOR SURFACE
AND GROUNDWATER. SURFACE WATER RUNOFF AND GROUNDWATER ON THE SOUTH SIDE
OF THE RIDGE FLOWS SOUTHWARD AND DISCHARGES INTO TOWN CREEK. SURFACE
WATER RUNOFF AND GROUNDWATER ON THE NORTH SIDE OF THE RIDGE DRAINS
NORTHWARD AND DISCHARGES INTO UNNAMED TRIBUTARIES TO TWELVE-MILE CREEK.
MOST OF THE SANGAMO WESTON PROPERTY, INCLUDING MANY OF THE INVESTIGATION
AREAS, IS FORESTED. THE ONLY UNFORESTED AREAS INCLUDE THE WASTEWATER
TREATMENT FACILITY, SEPTIC DRAIN FIELD, AREA A AND AREA F. THE
WASTEWATER TREATMENT FACILITY AND SEPTIC DRAIN FIELDS ARE VEGETATED WITH
GRASS AND WEEDS. AREA A IS COVERED WITH KUDZU. AREA F IS SURROUNDED
WITH FOREST AND IS COVERED WITH TALL GRASS, WEEDS, AND SAPLINGS. THE
MANUFACTURING FACILITY, INCLUDING THE PAVED PARKING LOT, IS NOT FORESTED
OR VEGETATED. HOWEVER, THE LAWN SURROUNDING THE FACILITY IS GRASSED,
WITH TREES.
THE SANGAMO WESTON PLANT SITE IS LOCATED IN THE PIEDMONT SECTION OF
SOUTH CAROLINA ON THE EASTERN SLOPE OF THE SOUTHERN APPALACHIAN
MOUNTAINS. THE FIRST RIDGE OF THE MOUNTAINS IS APPROXIMATELY TEN MILES
TO THE NORTH, AND THE MAIN RIDGE IS APPROXIMATELY FORTY MILES TO THE
NORTH. THESE MOUNTAINS GENERALLY PROTECT THIS AREA FROM THE FULL FORCE
OF COLD FRONTS WHICH MOVE SOUTHEASTWARD TOWARD THIS AREA IN THE WINTER
MONTHS.
THE TEMPERATURE RISES TO 90 DEGREE FAHRENHEIT OR ABOVE ON ALMOST HALF OF
THE DAYS DURING THE SUMMER MONTHS, BUT USUALLY FALLS TO 70 DEGREE
FAHRENHEIT OR LOWER DURING THE NIGHT. WINTERS ARE MODERATE, WITH THE
TEMPERATURE REMAINING BELOW FREEZING THROUGHOUT THE DAYLIGHT HOURS ONLY
THREE TO FOUR TIMES DURING A NORMAL YEAR. APPROXIMATELY TWO FREEZING
RAINSTORMS AND TWO OR THREE SMALL SNOWSTORMS OCCUR EACH WINTER. THE
MEAN ANNUAL TEMPERATURE FOR THIS AREA IS 60.7 DEGREE FAHRENHEIT.
1.2 THE BREAZEALE SITE
THE BREAZEALE SITE IS APPROXIMATELY SEVEN ACRES IN SIZE AND IS LOCATED
ABOUT ONE MILE SOUTH-SOUTHWEST OF PICKENS, ON WOLF CREEK ROAD (FIGURE
3). THE SOUTH AND SOUTHWEST PORTION OF THE SITE ARE LOCATED ON THE
FLOOD PLAIN OF WOLF CREEK WHICH BORDERS THE SITE TO THE SOUTH. SURFACE
ELEVATIONS RANGE FROM 872 FEET ABOVE MSL ALONG WOLF CREEK TO 910 FEET
ABOVE MSL AT THE NORTHWEST CORNER OF THE SITE.
A DRAINAGE DITCH BORDERS THE SITE TO THE EAST. THIS DITCH DRAINS
SOUTHWARD AND DISCHARGES INTO WOLF CREEK AT THE SOUTHEAST CORNER OF THE
SITE. WOLF CREEK BORDERS THE SITE TO THE SOUTH. APPROXIMATELY 1,500
FEET TO THE NORTHWEST AND UPSTREAM ON WOLF CREEK IS A DAM FOR A US SOIL
CONSERVATION SERVICE LAKE. SEEPAGE FROM THIS DAM CREATES MINOR FLOW IN
THE DRAINAGE DITCH ON THE EAST BOUNDARY OF THE SITE.
SURFACE WATER RUNOFF ON-SITE OCCURS AS A RESULT OF DIRECT PRECIPITATION.
SURFACE WATER ON-SITE DRAINS SOUTH TO SOUTHEAST TOWARD WOLF CREEK WHERE
1
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IT DISCHARGES. A SMALLER PORTION OF RUNOFF DRAINS EASTWARD TOWARDS THE
DRAINAGE DITCH. THE DRAINAGE DITCH DISCHARGES INTO WOLF CREEK. WOLF
CREEK FLOWS SOUTHWESTWARD ALONG THE SOUTH BOUNDARY OF THE SITE.
VEGETATION CONSISTS PRIMARILY OF GRASS COVER. STANDS OF TREES, SOME OF
WHICH ARE DENSE WITH THICK UNDERGROWTH OCCUR SOUTH OF THE AREA OF WASTE
DEPOSITION TO WOLF CREEK. ALONG THE BANKS OF WOLF CREEK ARE SMALL
TREES, SHRUBS AND THICK MARSH GRASS.
1.3 THE NIX SITE
THE NIX SITE IS APPROXIMATELY 7.5 ACRES IN SIZE AND IS LOCATED
APPROXIMATELY TWO MILES NORTHEAST OF PICKENS. THE SITE IS LOCATED JUST
WEST OF NORTH CEDAR ROCK ROAD BETWEEN GLASSY MOUNTAIN CHURCH ROAD AND
OLD FARRS BRIDGE ROAD (FIGURE 4).
A DIRT LOGGING ROAD LEADS FROM NORTH CEDAR ROCK ROAD TO THE SITE AREA.
AN UNNAMED TRIBUTARY TO WOLF CREEK IS LOCATED 100 FEET WEST OF THE SITE.
SURFACE ELEVATIONS RANGE FROM 1046 FEET ABOVE MSL AT THE WEST END OF THE
SITE TO 1,105 FEET ABOVE MSL AT THE EAST END OF THE SITE.
THE MOST PROMINENT SURFACE FEATURE ON THE NIX SITE IS A NATURALLY
OCCURRING 400 FOOT LONG RAVINE WHICH TRENDS FROM EAST TO WEST. THIS
RAVINE IS APPROXIMATELY THIRTY FEET DEEP ON ITS EASTERN END AND BECOMES
SHALLOWER TOWARD THE WESTERN END AS IT OPENS UP INTO A MARSH. A SMALL
MAN MADE POND IS LOCATED ON THE FAR WEST END OF THE SITE AT THE MOUTH OF
THE RAVINE. WATER FEEDING THE POND AND MARSH COMES FROM SMALL SPRINGS
AT THE HEAD OF THE MARSH AND FROM SURFACE RUNOFF. TWO STREAMS CREATED
BY THE OUT FALL FROM THE MAN MADE POND FLOW INTO THE UNNAMED TRIBUTARY
TO WOLF CREEK.
VEGETATION AT THE NIX SITE CONSISTS OF A GRASS COVERED PASTURE WITH
WOODED PORTIONS SOUTH OF THE RAVINE. TREES, TALL MARSH GRASSES AND
KUDZU ARE PRESENT IN THE RAVINE. VEGETATION NORTH OF THE RAVINE
CONSISTS OF GRASS, WEEDS, SMALL SHRUBS AND YOUNG TREES.
SURFACE WATER RUNOFF OUTSIDE OF THE RAVINE FLOWS WESTWARD AND DISCHARGES
DIRECTLY INTO THE UNNAMED TRIBUTARY. SURFACE WATER IN THE UNNAMED
TRIBUTARY OF WOLF CREEK, FLOWS SOUTH AND EMPTIES INTO WOLF CREEK
APPROXIMATELY ONE-HALF MILE SOUTHWEST OF THE SITE.
1.4 THE DODGENS SITE
THE DODGENS SITE IS LOCATED THREE MILES NORTHWEST OF PICKENS AND IS
ADJACENT TO THE MIDDLE FORK OF TWELVE-MILE CREEK (FIGURE 5). THE SITE
IN ABOUT 6.5 ACRES IN SIZE. THE SITE IS RELATIVELY FLAT WITH SURFACE
ELEVATIONS RANGING FROM 940 FEET ABOVE MSL ADJACENT TO THE CREEK TO
ABOUT 949 FEET ABOVE MSL AT THE WEST SIDE OF THE SITE; A TOPOGRAPHIC
RELIEF OF ABOUT NINE FEET. SHARP RISES IN TOPOGRAPHY OCCUR ALONG THE
NORTH, WEST AND SOUTH SIDE OF THE SITE. ELEVATIONS TO THE NORTH AND
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WEST EXCEED 970 FEET.
MIDDLE FORK TWELVE-MILE CREEK FLOWS SOUTHWARD ALONG THE EAST BOUNDARY OF
THE SITE. AN UNNAMED TRIBUTARY LOCATED ALONG THE SOUTHERN END OF THE
SITE FLOWS INTO THE CREEK. A SMALL MAN-MADE POND IS LOCATED AT THE
SOUTH END OF THE SITE.
NINE TIMES ROAD EXTENDS IN A NORTHWEST DIRECTION WEST OF THE SITE. A
DIRT ROAD LEADS FROM NINE TIMES ROAD TO THE SOUTH END OF THE SITE. THE
ROAD TURNS NORTHWARD AND EXTENDS ALONG THE WEST AND NORTH PERIMETER OF
THE SITE.
VEGETATION AT THE DODGENS SITE CONSISTS OF GRASS COVER. THE HILLS
BORDERING THE SITE TO THE NORTH, WEST AND SOUTH ARE COVERED WITH STANDS
OF TREES AND UNDERGROWTH. A DENSE STAND OF TREES AND UNDERGROWTH ALSO
EXTENDS ALONG THE BANKS OF MIDDLE FORK TWELVE-MILE CREEK AT THE EAST
SIDE OF THE SITE.
SURFACE WATER RUNOFF ON-SITE OCCURS AS A RESULT OF DIRECT PRECIPITATION.
ON-SITE SURFACE WATER DRAINS SOUTHEASTWARD TOWARDS MIDDLE FORK
TWELVE-MILE CREEK. THE CREEK FLOWS SOUTHWARD ALONG THE EAST BOUNDARY OF
THE SITE AND TURNS EASTWARD AT THE SOUTHEAST CORNER OF THE SITE. A
SMALL UNNAMED TRIBUTARY LOCATED ALONG THE SOUTHERN END OF THE SITE FLOWS
INTO THE CREEK. A SMALL STREAM ORIGINATING WEST OF THE SITE CROSSES
NINE TIMES ROAD, BORDERS THE SOUTHWEST PORTION OF THE SITE AND
DISCHARGES INTO THE UNNAMED TRIBUTARY. A PORTION OF SURFACE WATER FLOW
FROM THE STREAM IS DIVERTED TO A SMALL MAN-MADE POND LOCATED AT THE
SOUTH END OF THE SITE. THE OUTFALL FROM THE POND DISCHARGES INTO THE
UNNAMED TRIBUTARY. SURFACE WATER ON THE DODGENS SITE DRAINS DIRECTLY TO
MIDDLE FORK TWELVE-MILE CREEK.
1.5 THE CROSS ROADS SITE
THE CROSS ROADS SITE IS ABOUT FIVE ACRES IN SIZE AND IS LOCATED
APPROXIMATELY THREE MILES SOUTHWEST OF PICKENS (FIGURE 6). THE SITE IS
HEAVILY WOODED WITH AN UNNAMED TRIBUTARY TO TWELVE-MILE CREEK ALONG THE
SOUTHERN BOUNDARY. SURFACE ELEVATIONS RANGE FROM 11030 FEET MSL, IN THE
NORTHWEST PORTION OF THE SITE, TO 960 FEET IL ALONG THE UNNAMED
TRIBUTARY BORDERING THE SOUTHERN PORTION OF THE SITE, A TOPOGRAPHIC
RELIEF OF APPROXIMATELY SEVENTY FEET. A WIDE VARIETY OF DOMESTIC WASTE,
INCLUDING BOTTLES, CANS, AND CAR BODIES ARE DISPOSED THROUGHOUT THE
SITE.
PENROSE DRIVE EXTENDS IN A NORTHEAST-SOUTHEAST DIRECTION WEST OF THE
SITE. AN OLD ROADBED EXTENDS FROM PENROSE DRIVE ACROSS THE NORTHWEST
SECTION OF THE SITE. THIS ROAD IS FENCED OFF AT BOTH ENDS WHERE IT
EXITS THE SITE. SOUTH OF THE OLD ROADBED, IN THE NORTHWEST PORTION OF
THE SITE, IS AN ABANDONED HOME SITE. ALL THAT REMAINS IS AN ABANDONED
WELL (APPROXIMATELY FOUR FEET IN DIAMETER X TWENTY FEET DEEP), AN
OUTHOUSE AND VARIOUS HOUSEHOLD DEBRIS. THE CROSS ROADS SITE IS HEAVILY
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WOODED WITH PORTIONS CONTAINING DENSE UNDERGROWTH. DENSE UNDERGROWTH
ALSO EXTENDS ALONG THE BANKS OF THE UNNAMED TRIBUTARY OF TWELVE-MILE
CREEK.
SURFACE WATER RUNOFF ON-SITE OCCURS AS A RESULT OF DIRECT PRECIPITATION.
ON-SITE SURFACE WATER DRAINS SOUTHWARD TOWARDS THE UNNAMED TRIBUTARY OF
TWELVE-MILE CREEK. THE TRIBUTARY FLOWS EASTWARD ALONG THE SOUTHERN
BOUNDARY OF THE SITE AND TURNS NORTHEASTWARD AT THE SOUTHEAST CORNER OF
THE SITE. IT THEN CONTINUES IN THIS GENERAL DIRECTION FOR APPROXIMATELY
1,000 FEET WHERE IT DISCHARGES INTO TWELVE-MILE CREEK.
1.6 THE JOHN TROTTER SITE
THE JOHN TROTTER SITE IS ABOUT THREE ACRES IN SIZE AND IS LOCATED
APPROXIMATELY TWO MILES NORTH-NORTHEAST OF PICKENS NEAR TROTTER HILL
ROAD AND TOWN CREEK SCHOOL ROAD (FIGURE 7). THE SITE IS LOCATED BEHIND
A MACHINE SHOP. AN UNNAMED TRIBUTARY TO TOWN CREEK BORDERS THE
NORTHEASTERN PORTION OF THE SITE. SURFACE ELEVATIONS RANGE FROM 1,074
FEET ABOVE MSL, NEAR TROTTER HILL ROAD, TO 1,030 FEET ABOVE MSL NEAR THE
UNNAMED TRIBUTARY TO TOWN CREEK, A TOPOGRAPHIC RELIEF OF ABOUT
FORTY-FOUR FEET. A BROAD GRASSED PLAIN IS LOCATED ALONG THE WEST BANKS
OF THE TRIBUTARY NORTH OF THE SITE.
VEGETATION AT THE JOHN TROTTER SITE CONSISTS OF GRASS COVER SURROUNDING
THE MACHINE SHOP ON THE WESTERN END OF THE SITE WITH A DENSELY WOODED
AREA CONTAINING THICK UNDERGROWTH ON THE EASTERN END OF THE SITE. THE
LOW PLAIN AREA NORTH OF THE SITE IS VEGETATED WITH GRASS.
SURFACE WATER RUNOFF ON-SITE OCCURS AS A RESULT OF DIRECT PRECIPITATION.
ON-SITE SURFACE WATER DRAINS NORTH-EASTWARD TOWARDS THE UNNAMED
TRIBUTARY TO TOWN CREEK. THIS TRIBUTARY FLOWS SOUTH-EASTWARD ALONG THE
NORTHEASTERN BOUNDARY OF THE SITE AND EMPTIES INTO ANOTHER UNNAMED
TRIBUTARY TO TOWN CREEK. THE SECOND UNNAMED TRIBUTARY CONTINUES
SOUTH-SOUTHEAST AND EMPTIES INTO TOWN CREEK, 0.5 MILES SOUTH-SOUTHEAST
OF THE SITE.
1.7 THE WELBORN SITE
THE WELBORN SITE IS APPROXIMATELY FOUR ACRES IN SIZE AND IS LOCATED
ABOUT TWO MILES EAST OF PICKENS NEAR TURNER ROAD (FIGURE 8). THE SITE
IS MARKED BY ERODED AREAS WITH RAVINE DEPTHS AS MUCH AS TWENTY-FIVE
FEET. SITE ELEVATIONS RANGE FROM 1010 FEET ABOVE MSL, AT THE EAST SIDE
OF THE SITE, TO 1075 FEET MSL AT THE NORTHWEST PORTION OF THE SITE, A
TOPOGRAPHIC RELIEF OF SIXTY-FIVE FEET. SHARP CHANGES IN TOPOGRAPHY
OCCUR ALONG THE SIDES OF THE RAVINES.
THERE ARE NO STREAMS IN THE IMMEDIATE AREA OF THE SITE. APPROXIMATELY
600 FEET TO THE EAST IS AN UNNAMED TRIBUTARY OF WOLF CREEK WHICH FLOWS
SOUTH. WOLF CREEK IS APPROXIMATELY 1400 FEET SOUTH OF THE SITE AND
FLOWS SOUTHWESTWARD. VARIOUS TYPES OF DEBRIS INCLUDING HOUSEHOLD
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GARBAGE, GLASS, SCRAP METAL, LARGE METAL OBJECTS, (E.G., WASHING
MACHINES, AND INDUSTRIAL WASTE MATERIAL) ARE DEPOSITED IN THE RAVINES.
#SHEA
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
THE EXISTING SANGAMO WESTON PLANT WAS CONSTRUCTED IN THREE PHASES
BEGINNING IN 1955 WITH PLANT CONSTRUCTION FOR ELECTROLYTIC CAPACITOR
MANUFACTURING. ADDITIONS WERE MADE IN 1956 AND 1961 FOR THE POWER
FACTOR AND MICA CAPACITOR MANUFACTURING OPERATIONS.
THE MAJOR PRODUCTS MANUFACTURED BY THE SANGAMO WESTON PICKENS PLANT
INCLUDED ELECTROLYTIC CAPACITORS, MICA CAPACITORS, POWER FACTOR
CAPACITORS, AND POTENTIOMETERS. PCBS WERE USED AS THE DIELECTRIC FLUID
IN POWER FACTOR CAPACITORS. AROCLOR 1242, 1254 AND MCS 1016 (PRODUCTS
OF THE MONSANTO CORPORATION) WERE USED AS THE DIELECTRIC FLUIDS. IN THE
EARLY 1970S, THE FACILITY MADE A SWITCH TO MCS 1016 (A LESS CHLORINATED
PCB PRODUCT OF THE MONSANTO CORPORATION), FROM AROCLOR 1242, AS THE
PRIMARY DIELECTRIC FLUID.
IN 1968, CONSTRUCTION BEGAN ON A 1.4 MILLION GALLON/DAY (MGD) WASTEWATER
TREATMENT FACILITY. THE FACILITIES WERE COMPLETED IN 1970. THE SYSTEM
CONSISTED OF A PRIMARY SETTLING BASIN AND A LARGE STABILIZATION LAGOON.
THE TREATMENT SYSTEM WAS DESIGNED FOR (AMONG OTHER THINGS) THE
NEUTRALIZATION OF ACID SOLUTIONS USED IN THE ETCHING AND FORMING
PROCESSES AND FOR PRECIPITATION OF DISSOLVED MATERIALS SUCH AS ALUMINUM.
THE ALUMINUM PRECIPITATES SETTLED IN A PRIMARY SETTLING BASIN.
DURING THE 1970S AND INTO THE 1980S, A NUMBER OF SIGNIFICANT
MODIFICATIONS TOOK PLACE TO BOTH GENERAL PLANT OPERATIONS AND THE
OPERATION OF THE WASTEWATER TREATMENT FACILITIES. A BENTONITE CLAY
LAYER WAS ADDED TO THE STABILIZATION LAGOON TO HELP SETTLE PCB MATERIALS
THAT MIGHT BE PRESENT IN THE LIQUID PHASE. IN ADDITION, THE DRAINS FROM
THE TWO IMPREGNATION AREAS OF THE POWER FACTOR DIVISION WERE SEALED OFF
FROM THE WASTE TREATMENT FACILITIES. THIS ACTION WAS TAKEN TO ELIMINATE
THE PATHWAY OF PCB ENTRY INTO THE WASTEWATER SYSTEM.
THREE SEPTIC TANK DRAIN FIELD AREAS EXIST ON THE PLANT PROPERTY FOR
TREATMENT AND DISPOSAL OF SANITARY WASTEWATERS FROM THE PLANT. TWO
DRAIN FIELDS ARE LOCATED ADJACENT TO EACH OTHER IN AN AREA NORTH OF THE
BUILDING, A THIRD AREA IS LOCATED SOUTHWEST OF THE PLANT.
WASTE MATERIALS FROM PAST PRODUCTION ACTIVITIES HAVE BEEN DEPOSITED IN A
NUMBER OF AREAS ON THE SANGAMO WESTON PROPERTY. ON-SITE LANDFILLING
ACTIVITIES BEGAN IN THE MID 1950S AND CONTINUED OFF AND ON UNTIL 1972.
THE MATERIAL INCLUDED SCRAP CAPACITORS AND ALUMINUM HYDROXIDE SLUDGE AS
WELL AS OTHER ASSORTED INDUSTRIAL REFUSE. ON-SITE DISPOSAL OF PLANT
WASTE MATERIALS WAS DISCONTINUED IN JULY 1972.
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PRIOR TO 1972, GENERAL PLANT WASTE WAS ALSO DISPOSED AT PRIVATELY AND
PUBLICLY OWNED OFF-SITE AREAS IN THE PICKENS COUNTY AREA. SOME OF THE
MATERIALS TAKEN TO OFF-SITE DISPOSAL SITES CONTAINED PCBS.
AS PART OF THE MANUFACTURING PROCESS, ALL CAPACITORS WERE INSPECTED AND
TESTED. THE CAPACITORS THAT FAILED TO MEET QUALITY CONTROL CRITERIA
WERE DISCARDED ALONG WITH OTHER PROCESS AND NON-PROCESS SOLID WASTES.
THE SOLID WASTE WAS DISPOSED OF ON PLANT PROPERTY IN SEVERAL LOCATIONS
AND AT A NUMBER OF OFF-SITE LOCATIONS. THE OFF-SITE AREAS ADDRESSED IN
THIS ROD ARE DESIGNATED AS THE NIX, DODGENS, WELBORN, CROSS ROADS, JOHN
TROTTER AND BREAZEALE SITES.
IN THE MID-1970S, ENVIRONMENTAL MONITORING PROGRAMS BY EPA AND THE SOUTH
CAROLINA DEPARTMENT OF HEALTH AND ENVIRONMENTAL CONTROL (DHEC) LED TO
THE DETECTION OF POLYCHLORINATED BIPHENYLS (PCBS) IN THE SEDIMENTS OF
LAKE HARTWELL, ITS TRIBUTARIES, AND IN SOILS UNDERLYING FORMER DUMP
SITES IN PICKENS COUNTY THAT WERE USED BY THE SANGAMO WESTON, INC.
MANUFACTURING PLANT IN PICKENS. THE PCBS IN THE WATER RESOURCES WERE
TRACED TO EFFLUENT ASSOCIATED WITH THE SANGAMO PLANT, A PRODUCER OF
ELECTRIC CAPACITORS. THE PLANT USED PCBS AS A DIELECTRIC, OR
NON-CONDUCTING, FLUID IN CAPACITORS UNTIL 1977, WHEN THE FEDERAL
GOVERNMENT IMPOSED A BAN ON THE MANUFACTURE AND USE OF PCBS.
SOUTH CAROLINA DHEC FISH STUDY
IN 1974, DHEC CONDUCTED A PCB ANALYSIS OF FISH IN SOUTH CAROLINA AND
DETECTED PCBS IN A FISH SAMPLE AT TWO SITES IN THE TWELVE-MILE CREEK
AREA OF LAKE HARTWELL. FURTHER DHEC SAMPLING IN 1975 AND 1976
DEMONSTRATED ADDITIONAL PCB CONTAMINATION OF SEDIMENT AND OF FISH, ABOVE
THE US FOOD AND DRUG ADMINISTRATION (FDA) SAFE TOLERANCE LIMIT OF 5.0
PARTS PER MILLION (PPM). IN AUGUST 1976, DHEC, IN CONSULTATION WITH
EPA, INITIATED ANNUAL PCB TESTING OF FISH AND SEDIMENT IN LAKE HARTWELL.
THE SAME MONTH, EPA AND DHEC ISSUED A JOINT ADVISORY AGAINST CONSUMING
FISH FROM ANY PART OF THE LAKE. IN OCTOBER 1976, THE ADVISORY WAS
MODIFIED BASED ON FURTHER STUDY TO INCLUDE ONLY THE SENECA RIVER ARM OF
LAKE HARTWELL ABOVE HIGHWAY 24.
IN 1984, THE FDA LOWERED THE SAFE TOLERANCE LEVEL FROM 5.0 PPM TO 2.0
PPM. EPA AND DHEC EXPANDED THE EXISTING FISH CONSUMPTION ADVISORY TO
INCLUDE ALSO ALL FISH OVER THREE POUNDS CAUGHT ANYWHERE IN THE LAKE.
DHEC THEN REASSESSED ITS FISH TISSUE MONITORING PROGRAM AND DEVELOPED
MORE RIGOROUS SAMPLING PROCEDURES THAT WOULD ENABLE RESEARCHERS TO
ASSESS TRENDS. DHEC'S MONITORING PROGRAM WAS REVISED IN 1985 AND
INITIATED IN 1986.
FIVE SPECIES OF FISH OF SIMILAR WEIGHTS FOR EACH SPECIES WERE SAMPLED
$ROM 3-5 TESTING STATIONS. THE STATIONS WERE SELECTED BASED ON
HISTORICAL KNOWLEDGE OF PCBS IN THE LAKE AND WERE CHOSEN TO PROVIDE
COMPREHENSIVE COVERAGE. FOR EXAMPLE, SV-107 IN TWELVE-MILE CREEK
REPRESENTS THE MOST CONTAMINATED PORTION OF LAKE HARTWELL. THE TWO
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STATIONS IMMEDIATELY SOUTH OF THIS STATION, SV-532 AND SV-235, REPRESENT
A LARGE, OPEN-WATER AREA OF THE LAKE AS FAR REMOVED FROM THE
CONTAMINATION SOURCE AS POSSIBLE, AND SV-641 ALLOWS FOR CROSS
COMPARISONS BECAUSE IT IS IN THE OTHER MAJOR RIVER TRIBUTARY TO LAKE
HARTWELL AND IS NOT SUBJECT TO DIRECT PCB INPUT.
THE FISH IN DHEC'S RESEARCH INCLUDE CRAPPIE, LARGE MOUTH BASS AND HYBRID
BASS WHICH REPRESENT OVER EIGHTY PERCENT OF THE GAME FISH CAUGHT BY THE
PUBLIC. HYBRID BASS MOVE FROM PLACE TO PLACE, POTENTIALLY MOVE IN AND
OUT OF CONTAMINATED AREAS AND, THEREFORE, COULD DEMONSTRATE WORST-CASE
CONTAMINANT LEVELS IN FISH OUTSIDE THE ADVISORY AREA. WHITE AND CHANNEL
CATFISH ALSO ARE INCLUDED IN THE STUDY BECAUSE THEY DWELL ALONG AND FEED
OFF LAKE BOTTOMS WHERE PCB MOLECULES TEND TO SETTLE AND FORM HIGH
CONCENTRATIONS. CATFISH, THEREFORE, TEND TO INGEST MORE CONTAMINANTS
THAN FISH LIVING OR FEEDING IN OTHER LAYERS OF LAKES OR IN STREAMS.
DHEC SAMPLED PROPORTIONATE NUMBERS OF EACH OF THE FIVE SPECIES TO
ACCOUNT FOR VARIABILITY IN PCB LEVELS IN EACH SPECIES. FOR EXAMPLE, TEN
SAMPLES OF EACH OF THE FIRST THREE SPECIES, AND TWO OF EACH CATFISH
SPECIES ARE TAKEN AT EACH STATION. FEWER CATFISH ARE REQUIRED BECAUSE
THEY HAVE SHOWN THE LEAST VARIABILITY IN STUDY FINDINGS. EACH OF THE
FISH ARE STUDIED IN "MODIFIED WHOLE FORM", MINUS THE HEAD AND INTERNAL
ORGANS. EXCEPT FOR THE CATFISH, WHICH HAVE TOUGH AND OFTEN UNPALATABLE
SKIN, THE FISH ARE TESTED WITH THE SKIN ATTACHED. THE AGENCY USES THIS
APPROACH FOR TWO REASONS.
FIRST, TESTING THE WHOLE FISH, INCLUDING THE SKIN, PROVIDES A MORE
COMPLETE COUNT OF PCBS THAN WOULD TESTING FILLETS. SINCE PEOPLE
COMMONLY EAT FISH AS FILLETS, WITHOUT THE SKIN, THIS TESTING PROCEDURE
PROVIDES AN ADDED MARGIN OF SAFETY FOR PUBLIC HEALTH. SECOND, DHEC'S
METHOD AVOIDS THE DATA VARIATIONS THAT RESULT FROM THE FILLETING
PROCEDURES WHICH IS TRICKY. UNLESS EACH CUT IS EXACTLY THE SAME, THE
AMOUNT OF FAT INCLUDED IN THE SAMPLE WILL VARY. FAT CELLS ARE PRIME
"HOLDERS" OF PCB MOLECULES.
TO DATE, EVEN WITH REFINED RESEARCH METHODS, THE DATA OF PCB LEVELS
AMONG FISH IN LAKE HARTWELL VARY. DHEC'S 1986 FINDINGS, FOR EXAMPLE,
SHOWED THAT LARGE MOUTH BASS FROM THE TWELVE-MILE CREEK PORTION OF THE
LAKE, RANGING IN WEIGHT FROM 1.68 - 2.98 POUNDS, DEMONSTRATED A PCB
RANGE OF 3.64 PPM TO 130 PPM. WHILE THE FISH STUDY CONTINUES, DHEC AND
EPA ASSESS WHETHER THE FISH CONSUMPTION ADVISORY SHOULD REMAIN IN
EFFECT. THE MOST CURRENT READINGS SHOW THAT FISH ABOVE HIGHWAY 24
REGISTER AVERAGE PCB LEVELS ABOVE THE FDA LIMIT, FROM 2.22 PP IN CRAPPIE
TO 34.06 PPM IN LARGE MOUTH BASS. BELOW HIGHWAY 24, ONLY HYBRID BASS
AND CATFISH EXHIBITED THE EXCESS LEVELS AT A RANGE OF 5.48 PPM AND 2.05
PPM, REFLECTIVELY. THE FISH CONSUMPTION ADVISORY REMAINS IN EFFECT. IT
AND THE SAMPLING WILL CONTINUE UNTIL LEVELS FALL BELOW THE FDA TOLERANCE
LIMIT.
BREAZEALE SITE
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EPA AND SANGAMO ENTERED INTO AN ADMINISTRATIVE ORDER ON CONSENT ON
AUGUST 11, 1986 FOR AN IMMEDIATE REMOVAL ACTION ON THE BREAZEALE SITE.
IN ITS 103C NOTIFICATION, SANGAMO REPORTED DEPOSITING APPROXIMATELY
24,000 CUBIC FEET OF PCB WASTE FROM THE PLANT. PCB LEVELS AS HIGH AS
27,000 PPM WERE FOUND IN SOIL SAMPLES TAKEN BY EPA IN NOVEMBER 1985.
TWO MOBILE HOMES WERE ON THE SITE, BUT ONLY ONE WAS OCCUPIED.
AS A RESULT OF THIS ORDER, THE RESIDENTS WERE RELOCATED, THE SURFACE
DRAINAGE AT THE SITE WAS REROUTED, FENCING WAS CONSTRUCTED TO RESTRICT
SITE ACCESS, AND A GEOTEXTILE LINER AND SOIL CAP WERE ADDED AS AN
INTERIM MEASURE TO RETARD THE MIGRATION OF PCB CONTAMINATION.
NIX SITE
IN ITS 103C NOTIFICATION, SANGAMO REPORTED DEPOSITING APPROXIMATELY 10,
509 CUBIC YARDS OF PCB WASTE FROM THE PLANT. IN 1980, SANGAMO REMOVED A
TOTAL (FROM THE MIX AND DODGENS SITES) OF 17,711 CUBIC YARDS OF PCB
CONTAMINATED SOIL AND DEBRIS AND DISPOSED OF IT IN A LANDFILL ON THE
SANGAMO PLANT PROPERTY.
DODGENS SITE
IN ITS 103C NOTIFICATION, SANGAMO REPORTED DEPOSITING APPROXIMATELY
6,822 CUBIC YARDS OF PCB WASTE FROM THE PLANT. IN 1980, SANGAMO REMOVED
A TOTAL (FROM THE NIX AND DODGENS SITES) OF 17,711 CUBIC YARDS OF PCB
CONTAMINATED SOIL AND DEBRIS AND DISPOSED OF IT IN A LANDFILL ON THE
SANGAMO PLANT PROPERTY.
ON-SITE REMOVAL
IN 1989, DURING THE RI, AREA D ON THE PLANT PROPERTY WAS FOUND TO
CONTAIN PCB LEVELS AS HIGH AS 77,800 PPM. EPA SUPERVISED THE REMOVAL OF
7,285 TONS OF PCB CONTAMINATED SOIL AND DEBRIS TO THE GSX PERMITTED RCRA
LANDFILL IN PINEWOOD, SOUTH CAROLINA. IN ADDITION, 6,684 CAPACITORS
OVER 3 POUNDS WERE TAKEN TO AN APPROVED FACILITY FOR INCINERATION.
#HCP
3.0 HIGHLIGHTS OF COMMUNITY PARTICIPATION
INFORMATION REPOSITORIES FOR THIS SITE WERE ESTABLISHED IN THE PICKENS
COUNTY LIBRARY SYSTEM (PICKENS AND EASLEY BRANCHES) AND THE R.M. COOPER
LIBRARY AT CLEMSON UNIVERSITY IN CLEMSON, SOUTH CAROLINA. INFORMATION
IS ALSO AVAILABLE IN ATLANTA, GEORGIA IN THE EPA REGION IV REGIONAL
OFFICE. FACT SHEETS AND PRESS ADVISORIES WERE PREPARED PRIOR TO EACH
PUBLIC MEETING.
A COMMUNITY RELATIONS PLAN IDENTIFYING A POSITIVE PUBLIC OUTREACH
STRATEGY WAS DEVELOPED AT THE DIRECTION OF EPA REGION IV STAFF AND
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SUBMITTED TO THE INFORMATION REPOSITORIES PRIOR TO THE START OF WORK AT
THE SITE. A PUBLIC MEETING WAS HELD IN JUNE 1987 TO PRESENT THE RI/FS
WORK PLAN TO THE PUBLIC.
FACT SHEETS UPDATING LOCAL CITIZENS ON ACTIVITIES AT THE SITE WERE
ISSUED IN MAY 1987, FEBRUARY 1988, NOVEMBER 1988, DECEMBER 1989, JULY
1990 AND SEPTEMBER 1990. THE RI WAS SUMMARIZED IN THE DECEMBER 1989
FACT SHEET, AND AN OPPORTUNITY WAS PROVIDED FOR A PUBLIC MEETING. NO
ONE REQUESTED THAT EPA CONDUCT A MEETING AT THAT TIME.
EPA HELD A PUBLIC MEETING JULY 10, 1990 AT THE PICKENS COUNTY SENIOR
HIGH SCHOOL IN PICKENS, SOUTH CAROLINA TO PRESENT THE FEASIBILITY STUDY
RESULTS AND THE EPA'S PROPOSED PLAN FOR THE SITE. EPA PLACED PUBLIC
NOTICES OF THE MEETING IN THE GREENVILLE NEWS AND THE PICKENS COUNTY
SENTINEL AND DISTRIBUTED FACT SHEETS DESCRIBING EPA'S PROPOSED PLAN TO
CITIZENS AND OFFICIALS NOTED ON EPA'S SITE MAILING LIST. IN ADDITION,
EPA HELD A BRIEFING FOR LOCAL OFFICIALS PRIOR TO THE MEETING ON JULY 10,
1990.
EPA ALSO BRIEFED THE PICKENS COUNTY COUNCIL AT THEIR REGULARLY SCHEDULED
MEETING ON SEPTEMBER 17, 1990. IN ADDITION, EPA HELD AN AVAILABILITY
SESSION ON SEPTEMBER 20, 1990 IN LIBERTY, SOUTH CAROLINA. A SPECIALIST
FROM EPA'S CINCINNATI, OHIO OFFICE PRESENTED INFORMATION ON THERMAL
SEPARATION AND THEN EPA RESPONDED TO QUESTIONS AND COMMENTS FROM MEMBERS
OF THE AUDIENCE.
TRANSCRIPTS OF ALL THE PUBLIC MEETINGS WERE MADE AVAILABLE TO THE PUBLIC
THROUGH THE ADMINISTRATIVE RECORD FOR THE SITE.
#SROU
4.0 SCOPE AND ROLE OF OPERABLE UNIT
THIS RECORD OF DECISION ADDRESSES OPERABLE UNIT ONE OF THE SUBJECT SITE.
OPERABLE UNIT ONE CONSISTS OF GROUNDWATER AND SOURCE CONTAMINATION AT
THE PLANT SITE AND THE CROSS ROADS, NIX, BREAZEALE, DODGENS, JOHN
TROTTER AND WELLBORN SITES. THIS ROD ADDRESSES THE PRINCIPLE THREATS
POSED BY CONTAMINATION ASSOCIATED WITH OPERABLE UNIT ONE.
OPERABLE UNIT 2 CONSISTS OF THE TWELVE MILE CREEK BASIN AND LAKE
HARTWELL. AN RI/FS USING FUND MONEY HAS BEEN INITIATED AT OPERABLE UNIT
TWO AS OF SEPTEMBER 30, 1990.
#SSC
5.0 SUMMARY OF SITE CHARACTERISTICS
5.1 BREAZEALE PROPERTY
A TOTAL OF TWENTY-FIVE WELLS HAVE BEEN INSTALLED AT THE SITE.
THE MOST
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RECENT WELLS, BRMW-2A, 3B, 4A, 8B, 12A, 13, 14, 14A AND 15 WERE
INSTALLED AS A PART OF THE RI FROM MAY TO JULY 1988. FIFTEEN WELLS ARE
WATER TABLE MONITORING WELLS. TOTAL DEPTHS RANGE FROM 17 TO 40 FEET
BELOW LAND SURFACE. ONE WELL WAS DRILLED TO AN INTERMEDIATE DEPTH IN
THE SAPROLITE AND EIGHT WELLS WERE DRILLED TO THE TOP OF BEDROCK. DEPTH
TO TOP OF BEDROCK AS DETERMINED BY AUGER REFUSAL RANGES FROM 17 FEET
BELOW LAND SURFACE AT BRMW-13 TO 87 FEET BELOW LAND SURFACE AT BRMW-2A.
TWO WELLS WERE DRILLED 20 FEET INTO BEDROCK. WELLS BRMW-1 TO 15 ARE
WATER TABLE MONITORING WELLS. WELL BRMW-5A IS AN INTERMEDIATE DEPTH
WELL WITHIN THE SAPROLITE. MONITORING WELLS BRMW-2A, 3A, 4A, 5B, 8A,
12A AND 14A ARE DEEPER WELLS SCREENED ON TOP OF BEDROCK. WATER TABLE
WELL BRMW-13 ALSO EXTENDS TO BEDROCK. WELLS BRMW-3B AND BRMW-8B ARE
SCREENED FIFTEEN TO TWENTY FEET BELOW TOP OF BEDROCK AND MONITOR BEDROCK
GROUNDWATER QUALITY. A TOTAL OF THIRTY-ONE (31) SOIL BORINGS HAVE BEEN
INSTALLED AT THE BREAZEALE PROPERTY. TWELVE OF THESE BORINGS PENETRATED
WASTE MATERIAL AND WERE USED TO CHARACTERIZE THE WASTE AND DETERMINE ITS
VERTICAL EXTENT. SEVENTEEN SOIL BORINGS WERE DRILLED ADJACENT TO THE
AREA OF WASTE DEPOSITION TO VERIFY THE BOUNDARIES OF THE WASTE AND
LATERAL EXTENT OF PCBS IN SUBSURFACE SOILS.
MOST OF THE SITE IS UNDERLAIN BY RESIDUAL SOILS AND SAPROLITE. RESIDUAL
SOILS FOUND AT LAND SURFACE CONSIST PRIMARILY OF SANDY AND CLAYEY SILTS,
SILTY CLAYS AND MINOR SILTY SANDS APPROXIMATELY 7 TO 12 FEET THICK. THE
UNDERLYING SAPROLITE CONSISTS OF SANDS WITH VARIOUS AMOUNTS OF SILT,
CLAY AND MICA. THE SOUTH AND SOUTHWEST PORTIONS OF THE SITE BORDERING
WOLF CREEK ARE UNDERLAIN BY ALLUVIAL DEPOSITS. THESE DEPOSITS CONSIST
OF INTERBEDDED SANDY, SILTY CLAYS AND SILTY, CLAYEY SANDS. THE ALLUVIUM
HAS A THICKNESS OF APPROXIMATELY 20 FEET AND IS UNDERLAIN BY SANDY
SAPROLITE.
GROUNDWATER FLOW DIRECTION IS SOUTH-SOUTHWESTWARD TOWARDS WOLF CREEK.
THE HORIZONTAL GROUNDWATER GRADIENT FOR MOST OF THE SITE (INCLUDING THE
AREA OF WASTE DEPOSITION) IS 0.05 FEET PER FOOT. IN THE SOUTH TO
SOUTHEASTERN PORTION OF THE SITE (IN THE FLOOD PLAIN DEPOSITS) THE
GRADIENT IS ABOUT 0.01 FEET PER FOOT.
PRIOR TO THE INSTALLATION OF THE GEOTEXTILE LINER AND SOIL CAP (IN JULY
AND AUGUST 1987) CAPACITOR DEBRIS WAS EXPOSED AT THE LAND SURFACE.
WASTE (SOIL FILL WITH CAPACITOR DEBRIS) IS IN A TRENCH RANGING IN DEPTH
FROM 2.5 FEET BELOW THE SOIL CAP AT BORING W-2 TO 11.5 FEET BELOW THE
SOIL CAP AT W-10. THE AREA OF WASTE DEPOSITION IS 200 FEET LONG AND 50
FEET WIDE WITH AN AREA OF ABOUT 110 SQUARE YARDS. TOTAL WASTE VOLUME AT
THE SITE IS ESTIMATED TO BE 2,500 CUBIC YARDS.
TEN SURFACE WASTE SAMPLES WERE COLLECTED AT SITES WI THROUGH W-10 AND
ANALYZED FOR PCBS. PCB CONCENTRATIONS RANGE FROM 1.93 PPM AT W-1 TO
1800 PPM IN THE DUPLICATE SAMPLE OF W-5. ANALYTICAL RESULTS FOR THE
SURFACE WASTE IS PRESENTED IN TABLE 5-1.
ONE WASTE SAMPLE EACH WAS COLLECTED FROM SOIL/WASTE BORINGS W-2 THROUGH
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10 (A TOTAL OF NINE SAMPLES) AND WERE ANALYZED FOR PCBS. ANALYTICAL
RESULTS FOR WASTE SAMPLES ARE INCLUDED IN TABLE 5-1. SUBSURFACE PCB
CONCENTRATIONS RANGED FROM 3.7 PPM, IN SAMPLE W-9 (5.5-7 FEET), TO 1010
PPM IN SAMPLE W-7 (4-5.5 FEET).
SOIL/WASTE BORINGS W-11, 12 AND 13 WERE ADVANCED THROUGH THE WASTE
INTO THE UNDERLYING SOILS. SPLIT SPOON SAMPLES WERE COLLECTED
CONTINUOUSLY. WASTE SAMPLES COLLECTED FROM EACH BORING WERE COMBINED
INTO A SINGLE COMPOSITE WASTE SAMPLE, WHICH WAS THEN ANALYZED FOR THE
PRIORITY POLLUTANTS. ANALYTICAL RESULTS ARE INCLUDED IN TABLE 5-1.
TRICHLOROETHENE AND TETRACHLOROETHENE WERE DETECTED AT 0.0039 PPM AND
0.0058 PPM, RESPECTIVELY.
A LEACHING PROCEDURE (EP TOXICITY TEST) WAS PERFORMED ON THE COMPOSITE
WASTE SAMPLE FROM W-11, 12, 13 AND THE EXTRACT BEING ANALYZED FOR
PRIORITY POLLUTANT VOLATILE ORGANIC COMPOUNDS AND PCBS. THE ONLY
PARAMETER DETECTED WAS PCB (AROCLOR 1248) WITH A CONCENTRATION OF 0.0311
PPM.
SUBSURFACE SOILS WERE ANALYZED TO DETERMINE THE EXTENT OF PCBS AND OTHER
CONSTITUENTS BELOW THE LAND SURFACE ADJACENT TO AND BELOW THE WASTE.
SURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE EXTENT
OF PCBS ON THE LAND SURFACE.
FORTY-SIX SURFACE SOIL SAMPLES (BRSS-1 THROUGH 46) HAVE BEEN COLLECTED
AT THE BREAZEALE SITE. ALL OF THE SAMPLES WERE ANALYZED FOR PCBS ONLY.
TOTAL PCB CONCENTRATIONS ARE SUMMARIZED IN TABLE 5-2. TOTAL PCB
CONCENTRATION RANGED FROM NONE DETECTED AT BRSS-5, 7, 12, 26, 42 AND 44
TO 8280 PPM AT BRSS-17.
A TOTAL OF THIRTY-EIGHT SUBSURFACE SOIL SAMPLES HAVE BEEN COLLECTED AT
THE BREAZEALE SITE. BACKGROUND SOIL SAMPLE W-14 (0-17 FEET) AND THE
COMPOSITE SAMPLE OF W-11, 12, 13 COLLECTED BELOW THE WASTE WERE ANALYZED
FOR PRIORITY POLLUTANTS. AN EP TOXICITY TEST WAS PERFORMED ON A
DUPLICATE SAMPLE FOR W-11, 12, 13 AND ANALYZED FOR PRIORITY POLLUTANT
VOCS AND PCBS. SAMPLE BRSB-23 (10-12 FEET) COLLECTED ADJACENT SAMPLES
WERE ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS OF PCBS ARE PRESENTED
IN TABLE 5-3.
TOTAL PCBS DETECTED BELOW THE WASTE RANGED FROM NONE DETECTED IN SAMPLES
W-4 (5.5-7 FEET) AND W-5 (7-8.5 FEET) TO 65 PPM DETECTED IN W-9 (10-11.5
FEET).
TWENTY-FOUR SUBSURFACE SOIL SAMPLES WERE COLLECTED ADJACENT TO THE WASTE
FROM BORINGS BRSB-15 THROUGH 26. AT LEAST TWO SAMPLES WERE COLLECTED
FROM EACH BORING. TOTAL PCB CONCENTRATIONS DETECTED RANGED FROM 0.037
PPM IN BRSB-22 (3-4 FEET) TO 39 PPM DETECTED IN BRSB-24 (2-3 FEET).
TOTAL PCB CONCENTRATIONS DECREASED WITH DEPTH IN EACH BORING, USUALLY TO
BELOW DETECTION LIMITS.
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TETRACHLOROETHENE WAS FOUND IN A CONCENTRATION OF 0.0029 PPM IN THE SOIL
COMPOSITE FROM BORINGS W-11, 12 AND 13, COLLECTED DIRECTLY BELOW THE
WASTE. NO VOCS WERE DETECTED IN THE EP TOXICITY TEST FOR W-11, 12, 13.
CONCENTRATIONS OF THE SEMI-VOLATILE ORGANIC, DI-N-BUTYL PHTHALATE, WERE
DETECTED IN THE SOIL COMPOSITE OF BORINGS W-11 (12-22.5 FEET), 12
(3.5-20 FEET), 13 (12-18 FEET) AND THE SAMPLE FROM BORING W-14 (TABLE
5-4). BORING W-14 SERVES AS A SOURCE FOR BACKGROUND INFORMATION AS IT
WAS INSTALLED OUTSIDE AND UPGRADIENT OF THE AREA OF WASTE DEPOSITION.
SEVENTEEN INORGANIC COMPOUNDS WERE DETECTED IN SUBSURFACE SOILS.
PCBS WERE NOT DETECTED IN ANY OF THE WELLS. TETRACHLOROETHENE,
TRICHLOROETHENE AND TOTAL 1,2-DICHLOROETHENE (INCLUDING TRANS
1,2-DICHLOROETHENE) WERE THE PRIMARY VOLATILE ORGANIC COMPOUNDS
DETECTED. VOCS ARE MIGRATING EASTWARD TOWARD WELL BRMW-2 AND THEN
SOUTHWEST TOWARD WOLF CREEK. OF THE SEVEN WELL NESTS INSTALLED AT THE
BREAZEALE SITE, FOUR (BRMW-2/2A, BRMW-3/3A, BRMW-4/4A, BRMW-5/5A/5B)
DISPLAY A DECREASE IN VOC CONCENTRATIONS WITH DEPTH. THE PREDOMINANT
TREND IS TO HAVE HIGHER VOC CONCENTRATIONS NEAR THE WATER TABLE SURFACE
AND MUCH LOWER VOC CONCENTRATIONS IN THE DEEPER SAPROLITE AND BEDROCK;
INDICATING THAT VOCS WITHIN THE GROUNDWATER ARE MIGRATING PRIMARILY
HORIZONTALLY TOWARD WOLF CREEK.
SEMI-VOLATILE AND PESTICIDE ORGANIC COMPOUNDS WERE NOT DETECTED IN THE
THREE WELLS (BRMW-3, 5 AND 11) THAT WERE ANALYZED FOR THESE PARAMETERS.
ANALYTICAL RESULTS SUMMARIZING INORGANIC COMPOUNDS DETECTED IN BRMW-3, 5
AND 11 ARE IN TABLE 5-5. WELL BRMW-3 WAS ANALYZED FOR INORGANIC
COMPOUNDS. ONLY CADMIUM AND NICKEL WERE FOUND IN WELL BBMW-3. NINE
METALS WERE DETECTED IN THE NONFILTERED SAMPLE FOR BRMW-5. ONLY FIVE
METALS (MAGNESIUM, MANGANESE, POTASSIUM, ZINC AND SODIUM) WERE IN THE
FILTERED-SAMPLE FROM BBMW-5. EIGHT METALS WERE DETECTED IN THE
NONFILTERED SAMPLE FOR BRMW-11. ONLY FOUR METALS (MAGNESIUM, MANGANESE,
POTASSIUM AND ZINC) WERE DETECTED IN THE FILTERED SAMPLE FROM BRMW-11.
STREAM SEDIMENT SAMPLES WERE COLLECTED JULY 30, 1986 FROM TWO LOCATIONS
(BRSD-1 AND 2) IN THE DITCH DRAINING THE EAST END OF THE SITE AND FROM
THREE LOCATIONS (BRSD-3, 4 AND 5) LOCATED ON WOLF CREEK. SAMPLE SITE
BRSD-3 IS LOCATED ON WOLF CREEK UPGRADIENT OF THE DRAINAGE DITCH AND THE
SITE. BRSD-4 WAS COLLECTED FROM WOLF CREEK ADJACENT TO THE SITE AND
BRSD-5 WAS COLLECTED FROM WOLF CREEK DOWNGRADIENT OF THE SITE. PCB
ANALYTICAL RESULTS ARE PRESENTED IN TABLE 5-6.
PCBS WERE DETECTED IN SAMPLES BRSD-1 AND 2 AT TOTAL CONCENTRATIONS OF
0.32 PPM AND 1.8 PPM, RESPECTIVELY. NO PCBS WERE DETECTED IN SEDIMENT
SAMPLES COLLECTED FROM WOLF CREEK. SEVERAL SURFACE WATER SAMPLES HAVE
BEEN COLLECTED FROM THE DRAINAGE DITCH AND WOLF CREEK AT THE SAME
LOCATIONS AS STREAM SEDIMENT SAMPLES. A SUMMARY OF DETECTED PARAMETERS
IS PRESENTED IN TABLE 5-7. VOCS HAVE NOT BEEN DETECTED IN SAMPLES
BRSW-1 AND 2. ONLY SMALL CONCENTRATIONS OF VOCS HAVE BEEN DETECTED IN
SAMPLES COLLECTED FROM BRSW-3, 4 AND 5.
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5.2 NIX SITE
A REMOVAL OF WASTE WAS CONDUCTED IN 1980. SOIL BORINGS WERE DRILLED TO
DETERMINE THE HORIZONTAL AND VERTICAL EXTENT OF ANY REMAINING WASTE.
NINE SOIL BORINGS WERE DRILLED AT LOCATIONS ON THE SITE. DEPTHS OF SOIL
BORINGS RANGED FROM 3.7 TO 7.0 FEET BELOW LAND SURFACE. SOILS
UNDERLYING THE NIX SITE ARE RESIDUAL IN NATURE AND CONSIST OF FINE TO
COARSE GRAINED SILTY SAND AND CLAYEY SAND WITH ZONES OF SANDY SILT AND
CLAYEY SILT.
DURING FIELD ACTIVITIES FOR THE REMEDIAL INVESTIGATION, AN AREA
CONTAINING WASTE WAS IDENTIFIED ON THE SOUTH BANK OF THE RAVINE NEAR THE
WEST END. THE WASTE AT THIS LOCATION INCLUDES FOIL-WRAPPED CAPACITORS,
CAPACITOR PAPER AND FOIL FRAGMENTS. THIS WASTE COVERS A SURFACE AREA OF
ABOUT 50 SQUARE YARDS. TOTAL VOLUME OF THIS WASTE DEPOSIT IS
APPROXIMATELY 20 CUBIC YARDS. DOMESTIC WASTE (FURNITURE PARTS AND OLD
ROOFING SHINGLES) IS ALSO DISPOSED IN SEPARATE AREAS OF THE RAVINE.
CAPACITOR WASTE, INCLUDING FOIL-WRAPPED CAPACITORS, CAPACITOR PAPER AND
FOIL FRAGMENTS, IS SCATTERED ON THE GROUND SURFACE WITHIN THE RAVINE AND
ON THE LAND SURFACE 100 FEET TO EITHER SIDE OF THE RAVINE.
A SAMPLE OF WASTE WAS TAKEN FROM SOIL BORING NXSB-4, 0.7 TO 0.8 FEET
BELOW LAND SURFACE. BECAUSE OF THE LIMITED VOLUME OF SAMPLE AT THIS
SITE, SAMPLE NXSB-4 (0.7-0.8) WAS ANALYZED FOR VOCS ONLY. SAMPLE NXSS
22 WAS COLLECTED FROM WASTE PILED AT THE EAST SIDE OF THE RAVINE AND
ANALYZED FOR THE HSL PARAMETERS. ANALYTICAL RESULTS FOR WASTE ARE
PRESENTED ON TABLE 5-8. THE ONLY VOC DETECTED IN SAMPLE NXSB-4
(0.7-0.8) WAS METHYLENE CHLORIDE AT 0.008 PPM. SAMPLE NXSS-22 ALSO
CONTAINED METHYLENE CHLORIDE AT 0.008 PPM.
NO SEMI-VOLATILE OR PESTICIDE COMPOUNDS WERE DETECTED. PCBS WERE
DETECTED IN THE WASTE SAMPLE NXSS-22 AT A CONCENTRATION OF 13 PPM
(AROCLOR 1254).
SEVENTEEN OF THE HSL INORGANIC COMPOUNDS WERE DETECTED IN THE WASTE
SAMPLE NXSS-22.
SURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE EXTENT
OF PCBS ON THE LAND SURFACE. TWENTY-ONE SURFACE SOIL SAMPLES (NXSS-1
THROUGH NXSS-21) WERE COLLECTED. NXSS-22 WAS AN HSL SAMPLE OF THE WASTE
IN THE RAVINE AND IS NOT SURFACE SOIL. SAMPLES NXSS-1 TO 21 WERE
ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS ARE PRESENTED ON TABLE 5-9.
PCBS WERE NOT DETECTED IN SIX SAMPLES. TOTAL DETECTED PCB
CONCENTRATIONS RANGED FROM 0.130 PPM AT NXSS-2 TO 66 PPM AT NXSS-13.
SUBSURFACE SOILS WERE ANALYZED TO DETERMINE THE EXTENT OF PCBS AND OTHER
CONSTITUENTS BELOW THE LAND SURF ACE AND BELOW WASTE. TEN SUBSURFACE
SOIL SAMPLES WERE COLLECTED DURING THE REMEDIAL INVESTIGATION
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ACTIVITIES. ONE OF THESE SAMPLES WAS A COMPOSITE COLLECTED FROM BERINGS
NXSB-4, 4A AND 4B AND ANALYZED FOR THE HSL PARAMETERS, EXCEPT VOCS,
WHICH WERE TAKEN FROM NXSB-4. THE NINE REMAINING SAMPLES WERE ANALYZED
FOR PCBS ONLY. TABLE 5-10 PRESENTS RESULTS FOR PCB ANALYSIS OF
SUBSURFACE SOILS. TABLE 5-11 PRESENTS THESE HSL PARAMETERS DETECTED IN
COMPOSITE SAMPLE NXSB-4, 4A, 4B COLLECTED BELOW THE WASTE. THE COMPOUND
STYRENE WAS DETECTED IN SOIL SAMPLE NXSB-4, 4A, 4B AT 0.009 PPM.
FOURTEEN INORGANIC COMPOUNDS WERE DETECTED IN COMPOSITE SAMPLE NXSB-4,
4A, 4B AND ARE INCLUDED IN TABLE 5-11.
FOUR MONITORING WELLS (NXMW-1, 2, 3 AND 4) WERE INSTALLED AT THE NIX
SITE. WELLS NXMW-2 AND NXMW-3 WERE INSTALLED IN THE SAPROLITE ABOVE
BEDROCK. WELLS NXMW-1 AND NXMW-4 WERE INSTALLED INTO BEDROCK.
WELLS NXMW-1, 2 AND 3 ARE WATER TABLE WELLS.
NXMW-1 IS LOCATED
UPGRADIENT OF THE SITE AND PROVIDES BACKGROUND GROUNDWATER QUALITY DATA.
THE WATER TABLE AT WELL NXMW-1 OCCURS IN BEDROCK. LOCATIONS FOR NXMW-2
AND 3 WERE SELECTED TO MONITOR GROUNDWATER QUALITY ON EITHER SIDE OF THE
RAVINE, DOWNGRADIENT OF PAST WASTE DISPOSAL AREAS AND PRESENT SCATTERED
WASTE. IN THE AREA OF WELL NXMW-4, THE WATER TABLE IS WITHIN TWO FEET
OF THE GROUND SURFACE AND THE TOP OF BEDROCK IS ONLY THREE TO FOUR FEET
BELOW LAND SURFACE. FOR THIS REASON, A WATER TABLE WELL COULD NOT BE
INSTALLED. THEREFORE, WELL NXMW-4 WAS INSTALLED INTO ROCK AND MONITORS
BEDROCK WATER CONDITIONS DIRECTLY DOWNGRADIENT OF THE RAVINE.
GROUNDWATER SAMPLES WERE COLLECTED FROM MONITORING WELLS NXMW-1,2,3 AND
4 ON SEPTEMBER 8 AND 9, 1988 AND DECEMBER 6, 1988. FIRST ROUND SAMPLES
WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE, SUSPENDED
SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. WELL NXMW-3 WAS
ALSO ANALYZED FOR ALL OF THE HSL PARAMETERS. BOTH FILTERED AND
NON-FILTERED SAMPLES WERE COLLECTED FOR INORGANIC ANALYSIS. SECOND
ROUND SAMPLES WERE ANALYZED FOR PCBS, PH, SPECIFIC CONDUCTANCE,
SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES AND SULFATE. TABLE
5-12 SUMMARIZES RESULTS FOR DETECTED PARAMETERS.
PCBS WERE NOT DETECTED IN ANY OF THE WELLS DURING BOTH SAMPLING ROUNDS.
VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN THE FIRST ROUND GROUNDWATER
SAMPLE FOR WELL NXMW-4.
SEMI-VOLATILE AND PESTICIDE ORGANIC COMPOUNDS WERE NOT DETECTED IN THE
HSL ANALYSIS OF WELL NXMW-3. SAMPLES WERE OBTAINED FROM WELL NXMW-3 FOR
INORGANIC ANALYSIS. TEN INORGANIC COMPOUNDS WERE DETECTED IN THE
SAMPLE.
STREAM SEDIMENT SAMPLES WERE COLLECTED FROM 12 LOCATIONS. SEDIMENT
SAMPLE LOCATION NXSD-1 WAS CHOSEN TO DETERMINE PCB CONCENTRATIONS IN
SEDIMENTS IN THE EASTERN PORTION OF THE RAVINE. SAMPLE LOCATION NXSD-2
IS LOCATED ADJACENT TO THE AREA OF WASTE DEPOSITION NEAR THE WESTERN END
OF THE RAVINE AND PROVIDES PCB CONCENTRATIONS IN SEDIMENTS IN THE
DOWNGRADIENT AREA OF THE RAVINE. NXSD-3 AND 4 ARE LOCATED IN THE MARSH
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IMMEDIATELY DOWNGRADIENT OF THE RAVINE. SEDIMENT SAMPLING LOCATIONS
NXSD-4,6,7 AND 8 ARE LOCATED IN VARIOUS AREAS OF THE POND. SAMPLING
LOCATIONS FOR NXSB-9 AND 10 ARE LOCATED IN TWO OUTFALL STREAMS
DOWNGRADIENT OF THE POND. NXSB-11 IS LOCATED IN THE UNNAMED TRIBUTARY
TO WOLF CREEK UPGRADIENT OF THE SITE. THE SAMPLING LOCATION FOR NXSD-12
IS LOCATED ON THE UNNAMED TRIBUTARY TO WOLF CREEK DOWNGRADIENT OF THE
SITE. THESE SAMPLES WERE ANALYZED FOR PCBS TO DETERMINE THE PRESENCE
AND EXTENT OF PCB MIGRATION ALONG SURFACE DRAINAGE ROUTES. ANALYTICAL
RESULTS ARE PRESENTED ON TABLE 5-13.
PCBS WERE NOT DETECTED IN SEDIMENT SAMPLE NXSD-1 LOCATED IN THE
UPGRADIENT PORTION OF THE RAVINE. TOTAL PCB CONCENTRATION AT NXSD-2 WAS
3.9 PPM. SEDIMENT SAMPLES NXSD-3 AND 4, HAD TOTAL PCB CONCENTRATIONS OF
1.74 AND 1.62 PPM, RESPECTIVELY. PCB CONCENTRATIONS IN THE SEDIMENT
SAMPLES NXSD-5, 6, 7 AND 8 RANGED FROM 0.79 PPM AT NXSD-8 TO 1.56 PPM AT
NXSD-8. OF THE TWO SEDIMENT SAMPLES TAKEN FROM THE POND OUTFALL STREAMS
(NXSD-9 AND NXSD-10), PCBS WERE ONLY DETECTED IN NXSD-9 AT 0.65 PPM.
THERE WERE NO PCBS DETECTED AT NXSD-11 AND NXSW-12 LOCATED ON THE
UNNAMED TRIBUTARY TO WOLF CREEK LOCATED UP AND DOWNGRADIENT RESPECTIVELY
AT THE NIX SITE.
ONE ROUND OF SURFACE WATER SAMPLES WAS COLLECTED AT SAMPLES SITES
NXSW-2,4,6,9 10,11 AND 12. A SURFACE WATER SAMPLE FROM THE SEDIMENT
SAMPLE LOCATION NXSD-1 WAS PROPOSED IN THE RI WORK PLAN. HOWEVER, THERE
WAS NO WATER AT NXSD-1 AT THE TIME OF SAMPLING AND A SURFACE WATER
SAMPLE COULD NOT BE OBTAINED. SURFACE WATER SAMPLES WERE ANALYZED FOR
PCBS, PH AND SPECIFIC CONDUCTANCE.
PCBS WERE NOT DETECTED IN ANY OF THE SURFACE WATER SAMPLES.
5.3 DODGENS SITE
TWENTY-FOUR SOIL BORINGS WERE DRILLED IN LOCATIONS ON THE DODGENS SITE.
SOILS UNDERLYING THE DODGENS SITE CONSIST OF SILTY SANDS, SILTY CLAYS
AND CLAYEY SILTS. THIN LAYERS OF CAPACITOR DEBRIS (CAPACITOR PAPER,
FOIL) WERE PRESENT IN SOME BORINGS AT SHALLOW DEPTHS (LESS THAN THREE
FEET BELOW LAND SURFACE). SOIL BORINGS AND EXPLORATORY BORINGS WERE
DRILLED AS PART OF THE REMEDIAL INVESTIGATION TO CONFIRM ACTUAL WASTE
PRESENCE AND DETERMINE HORIZONTAL AND VERTICAL EXTENT OF THE AREA OF
WASTE DEPOSITION. WASTE SAMPLES WERE ANALYZED TO CHARACTERIZE THE WASTE
AND IDENTIFY THE CONSTITUENTS TO BE ADDRESSED FURTHER.
WASTE WAS PENETRATED BY BORINGS DGSB-1, 3, 3C, 4A, 4C, SC AND 6.
FOLLOWING INSTALLATION OF THE SOIL BORINGS, FIFTY-THREE EXPLORATORY
BORINGS WERE DRILLED TO FURTHER DEFINE THE AREA OF WASTE DEPOSITION.
WASTE, IN THE FORM OF CAPACITOR DEBRIS (FOIL, PAPER AND MICA PLATES), IS
PRESENT IN SIX AREAS THROUGHOUT THE DODGENS SITE. THE SMALLEST AREA,
LOCATED AT THE SOUTH END OF THE SITE HAS AN APPROXIMATE AREA OF 20
SQUARE YARDS. THE LARGEST AREA, LOCATED AT THE NORTHEAST END OF THE
SITE, HAS AN APPROXIMATE AREA OF 395 CUBIC YARDS.
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WASTE THICKNESS RANGES FROM TRACES ( LT 0.1 FOOT) AT BORINGS DGEB-21,
26, 38 AND 49 TO 1.0 FEET AT DGEB-50. TOTAL WASTE VOLUME AT THE SITE IS
ESTIMATED TO BE APPROXIMATELY 100 CUBIC YARDS.
A SAMPLE OF WASTE COLLECTED FROM SOIL BORING DGSB-4C AT 0.5 TO 2.0 FEET
BELOW LAND SURFACE DESIGNATED DGSB-4C (0.5-2.0 FEET) AND A COMPOSITE
SAMPLE OF WASTE COLLECTED FROM SOIL BORINGS 1, 3C AND 6 DESIGNATED
DGSB-1, 3C, 6 WERE ANALYZED FOR THE HSL PARAMETERS (VOC SAMPLES FOR
WASTE COLLECTED FROM BORINGS DGSB-1, 3C AND 6 WERE ANALYZED SEPARATELY
AND NOT COMPOSITED). ANALYTICAL RESULTS FOR WASTE ARE PRESENTED IN
TABLE 5-14 AND THE UPGRADIENT SURFACE SOIL SAMPLE DGSS-1 RESULTS ARE
PRESENTED IN TABLE 5-15.
FOURTEEN SEMI-VOLATILE COMPOUNDS WERE DETECTED IN THE COMPOSITE WASTE
SAMPLE DGSB-1, 3C, 6. PCBS WERE DETECTED IN WASTE SAMPLE DGSB-1, 3C, 6
AND DGSB-4C (0.5-2-2.0 FEET). TOTAL PCBS DETECTED IN COMPOSITE WASTE
SAMPLE DGSB-1, 3C, 6 WAS 470 PPM. TOTAL PCBS FOUND IN WASTE SAMPLE
DGSB-4C (0.5-2.0 FEET) WAS 30 PPM.
THE INORGANIC, CADMIUM, COPPER, IRON, LEAD, MANGANESE, MERCURY, SILVER,
VANADIUM AND ZINC WERE FOUND IN THE WASTE. SUBSURFACE SOILS WERE
ANALYZED TO DETERMINE THE EXTENT OF PCBS AND OTHER CONSTITUENTS BELOW
THE LAND SURFACE AND BELOW THE WASTE. SURFACE SOIL SAMPLES WERE
COLLECTED AND ANALYZED TO DETERMINE THE EXTENT OF PCBS ON THE LAND
SURFACE.
SURFACE SOIL-SAMPLES (DGSS-1 THROUGH DGSS-19) WERE COLLECTED AT VARIOUS
LOCATIONS ON THE SITE. DGSS-1 WAS ANALYZED TO DETERMINE THE EXTENT OF
PCBS AND OTHER CONSTITUENTS BELOW THE LAND SURFACE AND BELOW THE WASTE.
SURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE EXTENT
OF PCBS ON THE LAND SURFACE.
DGSS-1 WAS ANALYZED FOR THE HSL PARAMETERS. ANALYTICAL RESULTS ARE
PRESENTED ON TABLE 5-15. SAMPLES DGSS-2 THROUGH DGSS-18 WERE ANALYZED
FOR PCBS ONLY. TOTAL PCB CONCENTRATIONS ARE SUMMARIZED IN TABLE 5-16.
TOTAL PCB CONCENTRATIONS RANGED FROM 0.2 PPM AT DGSS-8 TO 270 PPM AT
DGSS-19. IN ADDITION TO PCBS, UPGRADIENT SURFACE SOIL SAMPLE DGSS-1 HAD
SEVERAL INORGANIC COMPOUNDS DETECTED.
IN ADDITION TO COMPOSITE WASTE SAMPLE DGSB-11 3C, 6 AND WASTE SAMPLE
DGSB-4 (0.5-2.0 FEET), TWENTY-FOUR SUBSURFACE SOIL SAMPLES WERE
ANALYZED. ONE SAMPLE DGSB-3C (6-10 FEET) WAS ANALYZED FOR THE HSL
PARAMETERS. THE REMAINING TWENTY-FOUR SUBSURFACE SOIL SAMPLES WERE
ANALYZED. ONE SAMPLE DGSB-3C (6-10 FEET) WAS ANALYZED FOR THE HSL
PARAMETERS. THE REMAINING TWENTY-FIVE SAMPLES WERE ANALYZED FOR PCBS
ONLY. ANALYTICAL RESULTS OF PCBS ARE PRESENTED IN TABLE 5-17.
ADDITIONAL PARAMETERS DETECTED IN THE HSL ANALYSIS OF SAMPLE DGSB-3C
(6-10 FEET) ARE PRESENTED IN TABLE 5-18. THE INORGANIC COMPOUNDS
MAGNESIUM AND SILVER, WERE DETECTED IN DGSB-3C (6-10 FEET). TOTAL PCBS
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DETECTED IN THE WASTE WERE 30 PPM IN DGSB-4C (0.5-2.0 FEET) AND 470 PPM
IN THE COMPOSITE WASTE SAMPLE DGSB-1, 3C AND 6.
THE HIGHEST CONCENTRATION OF PCBS, 2700 PPM, WAS DETECTED IN BORING
DGSB-5 AT THE DEPTH INTERVAL 4-6 FEET BELOW LAND SURFACE. BORING
DGSB-5C LOCATED WEST OF DGSB-5 HAD A CONCENTRATION OF 150 PPM IN THE
SAMPLE COLLECTED 4 TO 6 FEET BELOW LAND SURFACE. SOIL SAMPLES COLLECTED
FROM BORINGS DGSB-3C (3.0-4.5 FEET) AND DGSB-5A (4-6 FEET) HAD TOTAL PCB
CONCENTRATION OF 53.7 PPM AND 55 PPM RESPECTIVELY. THE TOTAL PCB
CONCENTRATION IN THE SOIL SAMPLE COLLECTED FROM DGSB-3C AT 6 TO 10 FEET
BELOW LAND SURFACE WAS 0.4 PPM.
THE REMAINING TWENTY-ONE SOIL SAMPLES HAD PCB CONCENTRATIONS RANGING
FROM NONDETECTED IN FIVE SAMPLES TO 22 PPM DETECTED IN A SAMPLE
COLLECTED FROM BORING DGSB-1 (3.5-5.0 FEET). MULTIPLE SAMPLES (2 OR 3)
OF SOIL AND WASTE WERE OBTAINED FROM EACH OF FIVE SOIL BORINGS, DGSB-1,
3C, 4C, SC AND 6. SAMPLES COLLECTED FROM BORING DGSB-4C HAD DECREASING
PCB CONCENTRATIONS WITH DEPTH. WASTE COLLECTED AT 0.5 TO 2 FEET BELOW
LAND SURFACE (COMPOSITED WITH WASTE COLLECTED FROM BORINGS DGSB-1 AND 6)
HAD A TOTAL PCB CONCENTRATION OF 30 PPM. NO PCBS WERE DETECTED IN THE
SOIL SAMPLE COLLECTED BELOW THE WASTE AT 3.0 TO 4.5 FEET BELOW LAND
SURFACE, AND 0.082 PPM TOTAL PCBS WERE DETECTED IN THE SOIL SAMPLE
COLLECTED AT 5.5 TO 7.0 FEET BELOW LAND SURFACE. THE REMAINING FOUR
BORE HOLES ALSO EXHIBITED DECREASES IN TOTAL PCB CONCENTRATIONS WITH
DEPTH.
FIVE MONITORING WELLS WERE INSTALLED AT THE DODGENS SITE. FOUR WELLS
(DGMW-1 THROUGH 4), ARE WATER TABLE MONITORING WELLS. WELL DGMW-3A IS A
DEEPER WELL AND FORMS A WELL PAIR WITH DGMW-3.
THE DODGENS SITE IS SITUATED ON FLOOD PLAIN DEPOSITS OF MIDDLE FORK
TWELVE-MILE CREEK. THESE DEPOSITS EXTEND FROM LAND SURFACE TO DEPTHS
RANGING FROM NINE FEET BELOW LAND SURFACE AT WELL DGMW-4 TO 18 FEET
BELOW LAND SURFACE OF WELL DGMW-3A.
WELLS DGMW-1, 2, 3, AND 4 ARE WATER TABLE MONITORING WELLS. DGMW-1 IS
LOCATED UPGRADIENT OF THE SITE AND PROVIDES BACKGROUND GROUNDWATER
QUALITY DATA. WELLS DGMW-2, 3 AND 4 MONITOR GROUNDWATER IMMEDIATELY
DOWNGRADIENT OF THE AREAS OF PAST AND PRESENT WASTE DEPOSITION. WELL
DGMW-3A IS A DEEPER WELL SCREENED ON TOP OF BEDROCK AND IS LOCATED
ADJACENT TO WELL DGMW-3. WELL DGMW-3A MONITORS DEEPER GROUNDWATER OF
THE AREA OF WASTE DEPOSITION. THE WATER TABLE RANGES FROM FIVE TO SEVEN
FEET BELOW LAND SURFACE.
FIRST ROUND SAMPLES WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC
CONDUCTANCE, SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES AND
SULFATE. BECAUSE SEVERAL SEMI-VOLATILE COMPOUNDS WERE DETECTED IN THE
HSL ANALYSIS OF COMPOSITE WASTE SAMPLE DGSB-1, 3C, 6, FIRST ROUND
GROUNDWATER SAMPLES WERE ALSO ANALYZED FOR SEMI-VOLATILE COMPOUNDS.
WELL DGMW-3 WAS ALSO ANALYZED FOR ALL OF THE HSL PARAMETERS DURING THE
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FIRST ROUND SAMPLING. BOTH FILTERED AND NON-FILTERED SAMPLES WERE
COLLECTED FOR INORGANIC ANALYSIS. TABLE 5-19 SUMMARIZES ANALYTICAL
RESULTS FOR DETECTED PARAMETERS.
NO VOLATILE ORGANIC COMPOUNDS (VOCS) WERE DETECTED IN GROUNDWATER DURING
THE FIRST SAMPLING ROUND IN AUGUST 1988; HOWEVER, VOCS WERE DETECTED IN
GROUNDWATER COLLECTED FROM WELLS DGMW-2, 3 AND 4 IN THE SECOND ROUND.
TRICHLOROETHENE WAS DETECTED IN WELLS DGMW-2 AND 3 AT CONCENTRATION OF
0.012 PPM AND 0.019 PPM, RESPECTIVELY. TETRACHLOROETHENE WAS DETECTED
IN GROUNDWATER COLLECTED FROM WELLS DGMW-2, 3 AND 4 AT CONCENTRATIONS OF
0.005 PPM, 0.005 PPM AND 0.006 PPM, RESPECTIVELY. DURING THE FIRST
SAMPLING ROUND, ALL FIVE WELLS WERE ANALYZED FOR THE SEMI-VOLATILE
COMPOUNDS. BIS(2-ETHYLHEXYL)-PHTHALATE WAS DETECTED IN WELLS DGMW-1,
3 AND 3A AT CONCENTRATIONS OF 0.011 PPM, 0.012 PPM, AND 0.013 PPM,
RESPECTIVELY: DI-N-OCTYLPHTHALATE WAS DETECTED IN THE GROUNDWATER SAMPLE
COLLECTED FROM WELL DGMW-3A AT A CONCENTRATION OF 0.012 PPM. DURING THE
FIRST SAMPLING ROUND, SAMPLES WERE OBTAINED FROM DOWNGRADIENT WELL
DGMW-3 FOR INORGANIC ANALYSIS. TWELVE INORGANIC COMPOUNDS WERE DETECTED
IN THE SAMPLE.
STREAM SEDIMENT SAMPLES WERE COLLECTED FROM SIX LOCATIONS ON MIDDLE FORD
TWELVE-MILE CREEK AND ITS TRIBUTARIES. SAMPLES WERE ANALYZED FOR PCBS.
SEDIMENT SAMPLING ANALYTICAL RESULTS ARE PRESENTED IN TABLE 5-20.
SAMPLING SITE DGSD-1 IS LOCATED ON MIDDLE FORK TWELVE-MILE CREEK
UPSTREAM OF THE DODGENS SITE AND PROVIDES BACKGROUND STREAM SEDIMENT
QUALITY. SAMPLE SITE DGSD-2 IS LOCATED ON MIDDLE FORK TWELVE-MILE CREEK
ADJACENT TO THE SOUTHEAST CORNER OF THE SITE AND UPGRADIENT TO THE
UNNAMED TRIBUTARY BORDERING THE SITE TO THE SOUTH. THIS SAMPLE WAS
COLLECTED TO DETERMINE PCB CONCENTRATIONS DOWNGRADIENT OF THE SITE, BUT
UPGRADIENT OF THE UNNAMED TRIBUTARY. SAMPLE SITE DGSD-3 IS LOCATED ON
THE UNNAMED TRIBUTARY UPSTREAM OF THE POND OUTFALL. SAMPLE SITE DGSD-4
IS LOCATED ON THE UNNAMED TRIBUTARY DOWNSTREAM IN THE SEDIMENT AS A
RESULT OF THE POND DISCHARGE. SAMPLE SITE DGSD-5 IS LOCATED ON MIDDLE
FORK TWELVE-MILE CREEK DOWNSTREAM OF THE UNNAMED TRIBUTARY AND WAS
SAMPLED TO DETERMINE IF PCBS ARE PRESENT DOWNGRADIENT OF ALL SITE
DRAINAGE. SEDIMENT SAMPLE SITE DGSD-6 IS LOCATED ON THE POND LOCATED
NEAR THE SOUTH END OF THE SITE.
NO PCBS WERE DETECTED IN UPSTREAM SEDIMENT SAMPLE DGSD-1. TOTAL PCB
CONCENTRATIONS OF 1.0 PPM AND 0.36 PPM (DUPLICATE) WERE DETECTED IN
SEDIMENT SAMPLE DGSD-2. THIS SAMPLE SITE IS LOCATED AT A POINT WHERE
SURFACE WATER RUNOFF FROM THE SITE DISCHARGES INTO MIDDLE FORK
TWELVE-MILE CREEK. NO PCBS WERE DETECTED IN SAMPLE DGSD-5 LOCATED
FURTHER DOWNSTREAM. NO PCBS WERE DETECTED AT DGSD-3 AND DGSD-4 LOCATED
ON THE UNNAMED TRIBUTARY. A TOTAL PCB CONCENTRATION OF 2.31 PPM WAS
DETECTED IN SEDIMENTS IN THE POND (DGSD-6).
ONE ROUND OF SURFACE WATER SAMPLES WERE COLLECTED AT SAMPLE SITES DGSW-1
THROUGH 6. THESE SAMPLE POINTS CORRESPOND WITH SEDIMENT SAMPLE POINTS
DGSD-1 THROUGH 6. SAMPLES WERE ANALYZED FOR PCBS AND SEMI-VOLATILE
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COMPOUNDS PH AND SPECIFIC CONDUCTANCE.
ARE PRESENTED IN TABLE 5-21.
A SUMMARY OF DETECTED PARAMETERS
NO PCBS WERE DETECTED IN ANY OF THE SURFACE WATER SAMPLES. NO
SEMI-VOLATILE COMPOUNDS WERE DETECTED IN UPGRADIENT SURFACE WATER SAMPLE
DGSW-1 AND SAMPLE DGSW-6 COLLECTED FROM THE POND. THE SEMI-VOLATILE
COMPOUND BIS (2-ETHYLHEXYL) PHTHALATE WAS DETECTED IN DGSW-2, DGSW-3,
DGSW-4, DGSW-5 AND THE DUPLICATE SAMPLE FOR DGSW-6.
5.4 CROSS ROADS SITE
SOILS AT THE CROSS ROADS SITE WERE CHARACTERIZED THROUGH EXAMINATION OF
SOIL SAMPLES COLLECTED FROM MONITORING WELL BORINGS AND SOIL BORINGS.
EIGHTEEN SOIL BORINGS WERE DRILLED TO DETERMINE THE VERTICAL EXTENT OF
THE WASTE, TO CHARACTERIZE THE WASTE AND TO DETERMINE THE PRESENCE OF
WASTE CONSTITUENTS IN UNDERLYING SOILS. SOILS UNDERLYING THE CROSS
ROADS SITE CONSIST OF SILTY SANDS AND SANDY SILTS WITH VARYING AMOUNTS
OF CLAY. WASTE, IN THE FORM OF CAPACITORS AND CAPACITOR DEBRIS (PAPER,
FOIL, AND MICA PLATES) WERE PENETRATED BY BORING CRSB-3, 4, 5, 7B AND
7C.
FOLLOWING THE INSTALLATION OF THE SOIL BORINGS, EIGHTEEN EXPLORATORY
BORINGS WERE DRILLED TO FURTHER DETERMINE THE HORIZONTAL AND VERTICAL
EXTENT OF THE AREA OF WASTE DEPOSITION. WASTE, IN THE FORM OF
CAPACITORS AND CAPACITOR DEBRIS, IS PRESENT IN AN AREA NEAR THE SOUTHERN
BORDER OF THE SITE. THIS AREA HAS AN APPROXIMATE AREA OF 1700 SQUARE
YARDS.
THE NORTHERN EXTENT OF THE WASTE WAS NOT DETERMINED IN THE VICINITY OF
EXPLORATORY BORING CREB-18. NORTH OF BORING CREB-18 IS HEAVILY WOODED
AND PREVENTED MOVEMENT OF THE DRILL RIG.
AS SHOWN ON TABLES 5-22 AND 5-23, WASTE THICKNESS RANGED FROM
APPROXIMATELY 0.1 FOOT AT BORINGS CREB-2 AND 18 TO 2.6 FEET AT CRSB-7C.
DEPTH TO THE TOP OF WASTE RANGED FROM 0.2 TO 1.8 FEET BELOW LAND
SURFACE. THE HORIZONTAL EXTENT OF THE AREAS OF WASTE DEPOSITION WERE
USED ALONG WITH WASTE THICKNESS TO DETERMINE THE VOLUME OF WASTE PRESENT
AT THE CROSS ROADS SITE. TOTAL VOLUME OF SANGAMO WESTON PROCESS WASTE
AT THE SITE IS APPROXIMATELY 400 CUBIC YARDS.
A COMPOSITE SAMPLE WAS MADE OF WASTE COLLECTED FROM SOIL BORING CRSB-3,
5, 7B AND 7C AND WAS ANALYZED FOR THE HSL PARAMETERS (VOC SAMPLES FOR
WASTE FROM BORINGS CRSB-3, 5 AND 7B WERE ANALYZED SEPARATELY AND NOT
COMPOSITED. ADDITIONALLY, A SAMPLE OF WASTE WAS COLLECTED FROM BORING
CRSB-4 AND ANALYZED FOR VOCS ONLY. ANALYTICAL RESULTS FOR WASTE ARE
PRESENTED IN TABLE 5-24.
THE VOLATILE ORGANIC COMPOUNDS, TOTAL 1,2-DICHLOROETHENE AND
TRICHLOROETHENE WERE DETECTED. NO SEMI-VOLATILE OR PESTICIDE COMPOUNDS
WERE DETECTED IN THE COMPOSITE WASTE SAMPLE. PCBS WERE DETECTED IN THE
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COMPOSITE WASTE SAMPLE CRSB-3, 5, 78, 7C WITH A TOTAL PCB CONCENTRATION
OF 118 PPM.
THE INORGANIC COMPOUNDS, CADMIUM, ZINC AND CYANIDE WERE DETECTED.
SUBSURFACE SOILS WERE ANALYZED TO DETERMINE THE EXTENT OF PCBS AND OTHER
CONSTITUENTS BELOW THE LAND SURFACE AND BELOW THE WASTE. SURFACE SOIL
SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE EXTENT OF PCBS ON
THE LAND SURFACE.
TWENTY-SEVEN SURFACE SOIL SAMPLES (CRSS-1 THROUGH CRSS-27) WERE
COLLECTED. CRSS-1 WAS ANALYZED FOR THE HSL PARAMETERS. ANALYTICAL
RESULTS ARE PRESENTED ON TABLE 5-25. SAMPLES CRSS-2 THROUGH CRSS-27
WERE ANALYZED FOR PCBS ONLY. TOTAL PCB CONCENTRATIONS ARE SUMMARIZED IN
TABLE 5-26. SAMPLE CRSS-9, LOCATED IN THE SOUTH CENTRAL PORTION OF THE
AREA OF WASTE DEPOSITION HAD A TOTAL PCB CONCENTRATION OF 410 PPM.
IN ADDITION TO COMPOSITE WASTE SAMPLE CRSB-3, 5, 78, 7C AND WASTE SAMPLE
CRSB-7B (1.7-2), TWENTY-SEVEN SUBSURFACE SOIL SAMPLES WERE ANALYZED.
ONE SAMPLE, CRSB-4 (5-7), WAS ANALYZED FOR THE HSL PARAMETERS. THE
REMAINING TWENTY-SIX SAMPLES WERE ANALYZED FOR PCBS ONLY. ANALYTICAL
RESULTS OF PCB CONCENTRATIONS ARE PRESENTED IN TABLE 5-27. ADDITIONAL
PARAMETERS DETECTED IN THE HSL ANALYSIS OF SAMPLE CRSB-4 (5-7) ARE
PRESENTED IN TABLE 5-28.
THE PESTICIDE HEPTACHLOR EPOXIDE WAS FOUND IN SAMPLE CRSB-4 (5-7) AT
0.01 PPM. PCB CONCENTRATIONS OF SUBSURFACE SAMPLES RANGED FROM NONE
DETECTED IN NINETEEN SAMPLES TO 3.5 PPM DETECTED IN A SAMPLE COLLECTED
FROM BORING CRWB-2 (0.0-1.5).
5
5.6 JOHN TROTTER SITE
TWENTY-EIGHT SOIL BORINGS WERE DRILLED IN LOCATIONS AT THE JOHN TROTTER
SITE. SOILS UNDERLYING THE JOHN TROTTER SITE CONSIST OF SILTY SANDS,
SILTY CLAYS AND CLAYEY SILTS. THIN LAYERS OF CAPACITOR WASTE (CAPACITOR
PAPER, FOIL) WERE PRESENT IN SOME BORINGS AT SHALLOW DEPTHS (LESS THAN
THREE FEET) BELOW LAND SURFACE. SOIL BORINGS AND EXPLORATORY BORINGS
WERE DRILLED AS PART OF THE REMEDIAL INVESTIGATION TO CONFIRM ACTUAL
WASTE PRESENCE AND DETERMINE HORIZONTAL AND VERTICAL EXTENT OF THE AREA
OF WASTE DEPOSITION. WASTE SAMPLES WERE ANALYZED TO CHARACTERIZE THE
WASTE AND IDENTIFY THE CONSTITUENTS.
WASTE WAS PENETRATED BY BORINGS JTSB-2, 2A, 3, 3A, 58, SC, AND SD.
FOLLOWING INSTALLATION OF THE SOIL BORINGS, SIX EXPLORATORY BORINGS WERE
DRILLED TO FURTHER DEFINE THE AREA OF WASTE DEPOSITION. WASTE WAS NOT
ENCOUNTERED IN ANY OF THE EXPLORATORY BORINGS.
WASTE, IN THE FORM OF CAPACITOR FOIL AND PAPER, IS PRESENT IN TWO AREAS
ON THE JOHN TROTTER SITE. THE LARGER OF THE TWO WASTE AREAS IS LOCATED
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IN AN EMBANKMENT ALONG THE NORTH EDGE OF THE GRAVEL ROAD. THE WASTE
AREA IS ABOUT 80 FEET LONG AND 15 FEET WIDE AND COMPRISES AN AREA OF
ABOUT 135 SQUARE YARDS. WASTE THICKNESS AS INDICATED BY BORINGS JTSB-2,
2A, 3 AND 3A IS ABOUT 0.5 FEET WITH THE TOP OF WASTE ABOUT ONE FOOT
BELOW LAND SURFACE. THE SECOND WASTE AREA IS LOCATED ABOUT 25 FEET
NORTHEAST OF THE LARGER WASTE AREA IN A LOWER, FLAT TURNAROUND AREA FOR
THE GARAGE. THE WASTE AREA IS APPROXIMATELY 18 FEET LONG AND 15 WIDE
AND COMPRISES AN AREA OF ABOUT 270 SQUARE FEET WASTE THICKNESS AS
INDICATED BY BORINGS JTSB-5B, 5C AND 5D WAS ABOUT 0.5 TO 1 FOOT WITH
DEPTH TO THE TOP OF WASTE AT 1.5 TO 2 FEET BELOW LAND SURFACE. TOTAL
WASTE VOLUME AT THE JOHN TROTTER SITE IS ESTIMATED TO BE APPROXIMATELY
100 CUBIC YARDS.
A COMPOSITE SAMPLE OF WASTE, COLLECTED FROM BORINGS JTSB-2A (1.0 TO 1.5
FEET BELOW LAND SURFACE), JTSB-3A (1.0 TO 1.5 FEET BELOW LAND SURFACE)
AND JTSB-5D (1.5 TO 1.9 FEET BELOW LAND SURFACE), DESIGNATED JTSB-2A,
3A, 5D WAS ANALYZED FOR HSL PARAMETERS (VOC SAMPLES OF WASTE COLLECTED
FROM BORINGS JTSB-2, 3 AND 5B WERE ANALYZED SEPARATELY AND NOT
COMPOSITED). ANALYTICAL RESULTS ARE PRESENTED IN TABLE 5-29.
TWO VOLATILE ORGANIC COMPOUNDS, TETRACHLOROETHENE AND TRICHLOROETHENE
WERE DETECTED IN THE WASTE. PCBS WERE DETECTED IN THE COMPOSITE WASTE
SAMPLE JTSB-2A, 3A, 5D AT A CONCENTRATION OF 750 PPM.
FIGHT INORGANIC COMPOUNDS, ANTIMONY, BARIUM, CADMIUM, COPPER, LEAD,
SILVER, MERCURY AND ZINC WERE DETECTED AT CONCENTRATIONS ABOVE THE RANGE
IN TABLE 5-30. BARIUM AND ZINC ARE WITHIN THE RANGE OF CONCENTRATIONS
IN TABLE 5-31. ANTIMONY, CADMIUM AND SILVER ARE NOT INCLUDED IN TABLE
5-31. CHINE SHOP DEBRIS WAS PRESENT ON THE LAND SURFACE ADJACENT TO THE
GARAGE.
THIRTY-SEVEN SURFACE SOILS SAMPLES (JTSS-1 THROUGH JTSS-37) WERE
COLLECTED AT THE SITE. JTSS-1 WAS ANALYZED FOR THE HSL PARAMETERS.
TABLE 5-32 SUMMARIZES PARAMETERS DETECTED IN JTSS-1. SAMPLES JTSS-2
THROUGH JTSS-37 WERE ANALYZED FOR VOCS AND PCBS ONLY. VOCS DETECTED
ALONG WITH TOTAL PCB CONCENTRATIONS ARE SUMMARIZED IN TABLE 5-33.
PCBS WERE DETECTED IN THIRTY TWO OF THE THIRTY-SEVEN SURFACE SOIL
SAMPLES COLLECTED. NO PCBS WERE DETECTED IN SAMPLES JTSS-1, 15, 21, 26
AND 35. TOTAL PCB CONCENTRATIONS RANGED FROM 0.053 PPM AT JTSS-24 TO 97
PPM AT JTSS-10. JTSS-10 AND JTSS-30, WITH TOTAL PCB CONCENTRATIONS OF
97 PPM AND 94 PPM, ARE THE ONLY SAMPLES TO EXCEED 50 PPM. THE REMAINING
SAMPLES HAD PCB CONCENTRATIONS RANGING FROM 0.053 PPM TO 14 PPM.
IN ADDITION TO THE COMPOSITE WASTE SAMPLE JTSB-2A, 3A, 5D, THIRTY
SUBSURFACE SOIL SAMPLES WERE ANALYZED. ONE SAMPLE, JTSB-5B (6.5-8.0
FEET) WAS ANALYZED FOR HSL PARAMETERS. THE REMAINING TWENTY-NINE
SAMPLES WERE ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS ARE PRESENTED
IN TABLE 5-34. ADDITIONAL PARAMETER DETECTED IN THE HSL ANALYSIS OF
SAMPLE JTSB-5B (6.5 - 8 FEET) ARE PRESENTED IN TABLE 5-35.
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PCBS WERE DETECTED IN FIFTEEN OF THE THIRTY SAMPLES COLLECTED. JTSB-3
HAD A TOTAL PCB CONCENTRATION OF 120 PPM. THIS SAMPLE WAS COLLECTED
BELOW THE LARGER WASTE AREA. THE 120 PPM TOTAL PCBS DETECTED IN JTSB-3
(5-6.5 FEET) IS MUCH LOWER THAN DETECTED IN THE OVERLYING WASTE
(73 PPM).
COMPOSITE WASTE SAMPLE JTSB-2A, 3A, 5D COLLECTED FROM BOTH AREAS OF
WASTE DEPOSITION HAD A TOTAL PCB CONCENTRATION OF 730 PPM. SOIL SAMPLES
COLLECTED FROM BORINGS JTSB-3 AND JTSB-5B HAD VARYING PCB CONCENTRATIONS
WITH DEPTH. JTSB-3 HAD A PCB CONCENTRATION OF 27 PPM AT 2.5 TO 4 FEET
BELOW LAND SURFACE (1 TO 2.5 FEET BELOW THE BOTTOM OF WASTE) AND HAD A
PCB CONCENTRATION OF 120 PPM AT 5 TO 6.5 FEET BELOW LAND SURFACE (3.5 TO
5 FEET BELOW THE BOTTOM OF WASTE). JTSB-5B HAD A PCB CONCENTRATION OF
0.42 PPM AT 4 TO 5.5 FEET BELOW LAND SURFACE (1 TO 2.5 FEET BELOW WASTE)
AND A CONCENTRATION OF 2.7 PPM AT 6.5 TO 8 FEET BELOW LAND SURFACE (3.5
TO 5 FEET BELOW WASTE).
GROUND WATER SAMPLES WERE COLLECTED FROM WELLS JTMW-1, 2, 3, 3A, 3B AND
4 IN NOVEMBER 1988 AND FEBRUARY 1989. SAMPLES FROM BOTH SAMPLING ROUNDS
WERE ANALYZED FOR PCBS, PH, SPECIFIC CONDUCTANCE, SUSPENDED SOLIDS,
ALKALINITY, HARDNESS, CHLORIDES AND SULFATE. ADDITIONALLY, DURING THE
FIRST SAMPLING ROUND ALL WELLS WERE SAMPLED FOR VOCS AND WELL JTMW-3 WAS
ANALYZED FOR ALL OF THE HSL PARAMETERS. TABLE 5-36 SUMMARIZES
ANALYTICAL RESULTS FOR DETECTED PARAMETERS.
NO PCBS WERE DETECTED IN ANY OF THE WELLS DURING EITHER SAMPLING EVENT.
DURING THE NOVEMBER 1988 SAMPLING, ONLY WELL JTMW-3 WAS ANALYZED FOR HSL
PARAMETERS. NO SEMI-VOLATILE OR PESTICIDE COMPOUNDS WERE DETECTED.
SEVENTEEN INORGANIC COMPOUNDS WERE FOUND IN THE SAMPLE. INORGANIC
COMPOUND CONCENTRATIONS IN THE SAMPLE WERE LOW, THEREFORE, METALS WERE
NOT INCLUDED IN THE ANALYTICAL PARAMETERS FOR THE SECOND ROUND OF GROUND
WATER SAMPLES COLLECTED IN FEBRUARY 1989.
STREAM SEDIMENT SAMPLES WERE COLLECTED IN NOVEMBER 1988 FROM TWO
LOCATIONS ON THE UNNAMED TRIBUTARY TO TOWN CREEK. SAMPLES WERE ANALYZED
FOR PCBS AND VOLATILE ORGANIC COMPOUNDS. ANALYTICAL RESULTS ARE
PRESENTED IN TABLE 5-37. SAMPLING SITE JTSD-1 IS LOCATED ON THE UNNAMED
TRIBUTARY TO TOWN CREEK UPSTREAM OF THE JOHN TROTTER SITE AND PROVIDES
BACKGROUND STREAM SEDIMENT QUALITY. SEDIMENT SAMPLING SITE JTSD-2 IS
LOCATED ON THE UNNAMED TRIBUTARY DOWNSTREAM OF THE SITE AND WAS SAMPLED
TO DETERMINE IF PCBS ARE PRESENT DOWNGRADIENT OF SITE DRAINAGE.
NO PCBS OR VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN UPSTREAM SEDIMENT
SAMPLE JTSD-1. A PCB CONCENTRATION OF 0.092 PPM WAS DETECTED IN JTSD-2
DOWNSTREAM OF THE JOHN TROTTER SITE. THIS PCB CONCENTRATION PROBABLY
OCCURRED AS A RESULT OF EROSION OF PCB BEARING SOILS WITH SURFACE WATER
RUNOFF ON-SITE.
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ONE ROUND OF SURFACE WATER SAMPLES WERE COLLECTED IN NOVEMBER 1988 AT
SAMPLING SITES JTSW-1 AND 2. THESE SAMPLING POINTS CORRESPOND WITH AND
SERVE THE SAME PURPOSE AS SEDIMENT SAMPLING POINTS JTSD-1 AND 2.
SURFACE WATER SAMPLES WERE ANALYZED FOR VOCS AND PCBS. NO VOCS OR PCBS
WERE DETECTED IN EITHER OF THE SURFACE WATER SAMPLES.
5.7 SANGAMO PLANT SITE
3.2.1 SOURCES
AREA A
SOIL BORINGS AND EXPLORATORY TRENCHES WERE INSTALLED AS PART OF THE
REMEDIAL INVESTIGATION TO DETERMINE ACTUAL WASTE PRESENCE, AND
HORIZONTAL AND VERTICAL EXTENT OF THE AREA OF WASTE DEPOSITION IN AREA
A.
NINE SOIL BORINGS WERE DRILLED IN AREA A. WASTE, IN THE FORM OF
ALUMINUM HYDROXIDE SLUDGE, WAS PENETRATED BY BORINGS SASB-1, 2, 2A, 3,
3A AND 48. WASTE WAS NOT FOUND IN THE THREE REMAINING SOIL BORINGS,
SASB-4, 4A AND 4C.
FOLLOWING INSTALLATION OF THE SOIL BORINGS, TWELVE EXPLORATORY TRENCHES,
LABELED SAST-1 THROUGH 12, WERE EXCAVATED TO FURTHER DETERMINE THE
HORIZONTAL AND VERTICAL EXTENT OF THE AREAS OF WASTE DEPOSITION.
EXPLORATORY TRENCHES WERE EXCAVATED WITH A BACKHOE AND VISUALLY
DESCRIBED BY THE ON-SITE RMT GEOLOGIST.
THE HORIZONTAL EXTENT OF WASTE WAS DETERMINED BY SOIL BORINGS AND
EXPLORATORY TRENCHES. WASTE SLUDGE IS PRESENT IN TWO ADJACENT LOCATIONS
AT AREA A. THE NORTHERN AREA OF WASTE DEPOSITION HAS A TOTAL AREA OF
280 SQUARE YARDS AND THE SOUTHERN HAS A TOTAL AREA OF 170 SQUARE YARDS.
WASTE THICKNESS RANGES FROM 1 FOOT AT BORING SASB-3 TO 9 FEET ON THE
WEST END OF TRENCH SAST-2.THE VOLUME OF WASTE PRESENT IN AREA A IS 500
CUBIC YARDS. WASTE VOLUME CALCULATIONS FOR ALL SITES WERE PRESENTED IN
DETAIL IN THE FEASIBILITY STUDY.
TWO COMPOSITE SAMPLES OF WASTE WERE COLLECTED FROM AREA A AND ANALYZED
FOR HSL PARAMETERS. ONE COMPOSITE SAMPLE WAS OBTAINED FROM SOIL BORINGS
SASB-1 AND SASB-2A IN THE NORTHERN WASTE AREA, AND ONE COMPOSITE SAMPLE
WAS OBTAINED FROM SOIL BORINGS SASB-3A AND SASB-4B IN THE SOUTHERN WASTE
AREA. VOC SAMPLES FOR WASTE COLLECTED FROM BORINGS SASB-1, 3A, 3A AND
4B WERE ANALYZED SEPARATELY AND NOT COMPOSITED. ANALYTICAL RESULTS FOR
WASTE ARE PRESENTED IN TABLE 5-38.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED. THE VOLATILE ORGANIC
COMPOUNDS METHYLENE CHLORIDE AND ACETONE WERE DETECTED IN MOST SAMPLES
COLLECTED (WASTE, SOILS, SEDIMENTS AND WATER) AT ALL OF THE SITES.
CARBON DISULFIDE WAS ALSO DETECTED IN SEVERAL SAMPLES AT SOME OF THE OFF
SITE AREAS.
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ONLY FOUR OF THE WASTE SAMPLES HAD VOCS OTHER THAN METHYLENE CHLORIDE OR
ACETONE. THESE CONCENTRATIONS WERE ALL LESS THAN 1 PPM. THESE
COMPOUNDS WERE NOT DETECTED IN ANY OF THE OTHER WASTE SAMPLES. VOCS
WERE NOT DETECTED IN WASTE COLLECTED FORM THE NORTH WASTE AREA.
PCBS WERE FOUND IN BOTH OF THE COMPOSITE WASTE SAMPLES, SASB-1, 2A AND
SASB-3A, 4B. TOTAL PCB CONCENTRATION IN SASB-1, 2A WAS 17.4 PPM.
SAMPLE SASB-3A, 4B HAD A TOTAL PCS CONCENTRATION OF 22,900 PPM. AS THE
SLUDGE IS FROM THE WASTEWATER TREATMENT FACILITY, THIS IS EXPECTED.
TABLE 5-34 PRESENTS HSL INORGANIC COMPOUND CONCENTRATIONS DETECTED IN
UPGRADIENT SURFACE SOILS FOR ALL OF THE SITES AND AREAS ADDRESSED IN THE
REMEDIAL INVESTIGATION. TABLE 5-31 PRESENTS THE RANGE OF SELECTED
INORGANIC COMPOUNDS DETECTED IN SOILS IN GEORGIA, SOUTH CAROLINA AND
NORTH CAROLINA OBTAINED FROM "CHEMICAL ANALYSES OF SOILS AND OTHER
SURFICIAL MATERIALS OF THE CONTERMINOUS UNITED STATES" (USGS, 1981).
THE RANGE OF CONCENTRATIONS ON TABLES 5-30 AND 5-31 ARE USED FOR
COMPARISON WITH DOWNGRADIENT WASTE AND SOIL SAMPLES FOR EACH SITE OR
AREA.
THE INORGANIC COMPOUNDS ALUMINUM, ARSENIC, COPPER MANGANESE AND SILVER
WERE FOUND AT CONCENTRATIONS HIGHER THAN THE RANGE OF CONCENTRATIONS
DETECTED IN THE UPGRADIENT SURFACE SOIL SAMPLES (TABLE 5-34). COPPER
AND MANGANESE WERE BELOW THE RANGE FOR GA, SC AND NC (TABLE 5-31).
NINETEEN SURFACE SOIL SAMPLES (SASS-1 THROUGH SASS-19) WERE COLLECTED.
SASS-1 WAS ANALYZED FOR THE HSL PARAMETERS. SAMPLES SASS-2 THROUGH
SASS-19 WERE ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS FOR SASS-1 ARE
PRESENTED ON TABLE 5-39. PCB CONCENTRATIONS DETECTED IN ALL SURFACE
SOIL SAMPLES ARE SUMMARIZED IN TABLE 5-40. PCBS WERE DETECTED IN
NINETEEN SURFACE SOIL SAMPLES. TOTAL PCB CONCENTRATIONS RANGED FROM 2.4
PPM AT SASS-18 TO 1880 PPM AT SASS-12. THIRTEEN SURFACE SOIL SAMPLES
INCLUDING UPGRADIENT SAMPLE SASS-1, EXCEEDED 50 PPM TOTAL PCBS. TEN OF
THESE SAMPLES WERE COLLECTED IN THE IMMEDIATE VICINITY OF THE AREAS OF
WASTE DEPOSITION. PCBS WERE ALSO DETECTED IN SURFACE SOIL SAMPLES
COLLECTED DOWNGRADIENT AT AREA A, TWO OF WHICH EXCEEDED 50 PPM (SASS-16
AND SASS-19).
IN ADDITION TO COMPOSITE WASTE SAMPLES SASB-1, 2A AND SASB-3A, 4B, NINE
SUBSURFACE SOIL SAMPLES WERE COLLECTED FROM BELOW OR ADJACENT WASTE, AND
ANALYZED FOR PCBS. ADDITIONALLY, ONE SAMPLE COLLECTED BELOW THE WASTE
FROM BORING SASB-3A, DESIGNATED SASB-3A (11-13), WAS ANALYZED FOR HSL
PARAMETERS. ANALYTICAL RESULTS FOR PCBS ARE PRESENTED IN TABLE 5-41.
ADDITIONAL PARAMETERS DETECTED IN THE HSL ANALYSIS OF SAMPLE SASB-3A
(11-13) ARE PRESENTED IN TABLE 5-42. TOTAL PCB CONCENTRATIONS ARE ALSO
SHOWN ON WASTE RANGED FROM 17.4 PPM IN COMPOSITE SASB-1, 2A, COLLECTED
FROM THE NORTH WASTE AREA TO 22,900 PPM IN COMPOSITE SAMPLE SASB-3A, 4B
COLLECTED FROM THE SOUTH WASTE AREA. ONLY FOUR SUBSURFACE SOIL SAMPLES,
SASB-3 (8-0), SASB-3A (11-13), SASB-4A (4-6) AND SASB-4C (13-15) HAD PCB
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CONCENTRATIONS EXCEEDING 50 PPM.
SOIL SAMPLE SASB-2 (6-8) COLLECTED ADJACENT TO THE NORTH WASTE AREA AND
SAMPLES SASB-1 (6-8), SASB-1 (9-11), SASB-2A (6-8) AND SASB-2A (9-11),
COLLECTED BELOW THE NORTH WASTE AREA HAD TOTAL PCB CONCENTRATIONS
RANGING FROM 0.053 PPM TO 2.67 PPM (MUCH LOWER THAN THE 17 4 PPM
DETECTED IN THE WASTE IN THE NORTH AREA). NONE OF THE WASTE OR
SUBSURFACE SOIL SAMPLES COLLECTED AT THE NORTH WASTE AREA EXCEEDED 50
PPM TOTAL PCBS.
SUBSURFACE SOIL SAMPLE SASB-3A (11-13) COLLECTED BELOW THE WASTE IN THE
SOUTH AREA WAS ANALYZED FOR HSS PARAMETERS. NO VOCS OR PESTICIDES WERE
DETECTED. ONLY ONE SEMI-VOLATILE COMPOUND, BIS (2-ETHYLHEXYL)
PHTHALATE, WAS DETECTED. ONE INORGANIC COMPOUND, COBALT, EXCEEDED THE
RANGE OF CONCENTRATIONS ON TABLE 5-31. COBALT WAS DETECTED AT LOWER
CONCENTRATIONS IN THE WASTE. SILVER WAS DETECTED ABOVE THE RANGE OF
CONCENTRATIONS IN TABLE 5-30.
SOIL SAMPLES WERE COLLECTED AT 0 TO 1.5 FEET AND 1.5 TO 3 FEET BELOW
LAND SURFACE AT PROPOSED LOCATIONS FOR WELLS SAMW-2 AND SAMW-3 LOCATED
ADJACENT TO THE SOUTH AREA OF WASTE DEPOSITION AND ANALYZED FOR PCBS.
ANALYTICAL RESULTS ARE ALSO INCLUDED IN TABLE 5-41. TOTAL PCB
CONCENTRATION RANGED FROM 13.1 PPM TO 340 PPM.
GROUND WATER SAMPLES WERE COLLECTED FROM ALL AREA A WELLS (SAMW-1, 2 AND
3). SAMPLES WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE,
SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. IN
ADDITION, WELL SAMW-3 WAS ANALYZED FOR ALL OF THE HSL PARAMETERS.
SAMPLES WERE COLLECTED FOR INORGANIC ANALYSIS. TABLE 5-43 SUMMARIZES
ANALYTICAL RESULTS FOR PARAMETERS DETECTED IN ALL SAMPLES.
NO PCBS WERE DETECTED IN ANY OF THE AREA A WELLS. TRICHLOROETHENE WAS
DETECTED IN ALL THREE WELLS IN JANUARY 1989. TETRACHLOROETHENE WAS ALSO
DETECTED IN ALL THREE WELLS AT SIMILAR CONCENTRATIONS, 0.005 PPM TO
0.007 PPM. TOTAL 1,2-DICHLOROETHENE WAS DETECTED IN WELL SAMW-3 AT
0.018 PPM IN OCTOBER 1988, AND 0.022 PPM IN JANUARY 1989.
SEMI-VOLATILE AND PESTICIDE COMPOUNDS WERE NOT DETECTED IN THE ONE HSL
ANALYSIS OF SAMW-3.
DURING THE FIRST SAMPLING ROUND IN OCTOBER 1988, GROUND WATER SAMPLES
WERE OBTAINED FROM WELL SAMW-3 AND ANALYZED FOR INORGANIC COMPOUNDS.
METAL CONCENTRATIONS WERE LOW; THEREFORE, METALS WERE NOT INCLUDED IN
THE ANALYTICAL PARAMETERS FOR THE SECOND ROUND OF GROUND WATER SAMPLES
COLLECTED IN JANUARY 1989. EPA WAS NOTIFIED OF THE ELIMINATION OF
METALS AND SEMI-VOLATILE COMPOUNDS FROM THE ANALYTICAL PARAMETER LIST IN
A LETTER DATED JANUARY 10, 1989.
AREA B:
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SOIL BORINGS, EXPLORATORY BORINGS, AND ONE EXPLORATORY TRENCH WERE
INSTALLED AS PART OF THE REMEDIAL INVESTIGATION TO DETERMINE WASTE
PRESENCE, AND TO INVESTIGATE THE HORIZONTAL AND VERTICAL EXTENT OF THE
AREAS OF WASTE DEPOSITION. A TOTAL OF NINE SOIL BORINGS WERE DRILLED.
WASTE IN THE FORM OF CAPACITOR DEBRIS, SLUDGE, RESINOUS MATERIAL, AND
DRUMS WAS FOUND IN BORING SBSB-1, SBSB-2B AND SBSB-3A. NO WASTE WAS
FOUND IN THE SIX REMAINING SOIL BORINGS.
FOLLOWING INSTALLATION OF THE SOIL BORINGS, FIVE EXPLORATORY BORINGS
WERE INSTALLED TO FURTHER DETERMINE THE HORIZONTAL AND VERTICAL EXTENT
OF WASTE DEPOSITION. AN EXPLORATORY TRENCHING PROGRAM WAS ALSO
INITIATED TO FURTHER DEFINE THE WASTE IN AREA B. HOWEVER, DRUMS WERE
ENCOUNTERED IN THE FIRST EXPLORATORY TRENCH (SBST-1) AND TRENCHING WAS
DISCONTINUED IN ORDER TO AVOID PUNCTURING THE DRUMS. THE VERTICAL
EXTENT OF WASTE HAS BEEN ESTIMATED. THE WASTE HAS BEEN DISPOSED IN
THREE AREAS: ONE ABOVE-GROUND DISPOSAL AREA AT THE NORTH END OF AREA 5,
AND TWO SUBSURFACE DISPOSAL AREAS. WASTE IN THE ABOVE-GROUND DISPOSAL
AREA CONSIST OF WOOD PALLETS AND CAPACITOR DEBRIS. THE ABOVE-GROUND
WASTE AREA HAS AN APPROXIMATE SURFACE AREA OF 180 SQUARE YARDS. THE
NORTH AREA OF SUBSURFACE WASTE HAS AN AREA OF 80 SQUARE YARDS AND AN
ESTIMATED VOLUME OF 300 CUBIC YARDS. THE SOUTHERNMOST AREA OF WASTE
DEPOSITION HAS A SURFACE AREA OF 95 SQUARE YARDS AND AN ESTIMATED VOLUME
OF 250 CUBIC YARDS.
A SAMPLE OF WASTE COLLECTED FROM EXPLORATORY TRENCH SBST-1, AND A
COMPOSITE SAMPLE OF WASTE COLLECTED FROM SOIL BORINGS 2B AND 3
(DESIGNATED SBSB-2B, 3), WERE ANALYZED FOR THE HSL PARAMETERS. SAMPLES
OF WASTE FOR VOC ANALYSIS WERE COLLECTED FROM BORINGS SBSB-2B AND 3 AND
ANALYZED SEPARATELY. ANALYTICAL RESULTS FOR WASTE ARE PRESENTED ON
TABLE 5-44.
SEVERAL VOCS AND SEMI-VOLATILE COMPOUNDS WERE DETECTED IN THE WASTE.
TRICHLOROETHENE AND TETRACHLOROETHENE WERE MOST COMMON. PCBS WERE
DETECTED IN WASTE SAMPLES SBST-1 AND IN THE COMPOSITE SAMPLE SBSB-2B, 3.
TOTAL PCBS DETECTED IN COMPOSITE WASTE SAMPLE SBSB-2B, 3, AND IN THE
EXPLORATORY TRENCH WASTE SAMPLE WERE 31 PPM AND 920 PPM, RESPECTIVELY.
THE INORGANIC COMPOUNDS ALUMINUM, CALCIUM, LEAD, MAGNESIUM, SILVER AND
CYANIDE WERE FOUND IN THE WASTE AT CONCENTRATIONS ABOVE THE RANGE
DETECTED IN TABLE 5-30. LEAD AND MAGNESIUM CONCENTRATIONS ARE WITHIN
THE RANGE IN TABLE 5-31.
TWENTY-TWO SURFACE SOIL SAMPLES, (SBSS-1 THROUGH SBSS-22), WERE
COLLECTED IN AREA 5. UPGRADIENT SOIL SAMPLE SBSS-1 WAS ANALYZED FOR HSL
PARAMETERS. THE REMAINING SAMPLES WERE ANALYZED FOR PCBS AND VOCS.
TABLE 5-45 SUMMARIZES THOSE PARAMETERS DETECTED IN SBSS-1. PCB,
SEMI-VOLATILES AND VOC CONCENTRATIONS FOR ALL SURFACE SOIL SAMPLES ARE
PRESENT IN TABLE 5-46. PCBS WERE DETECTED IN TWENTY-TWO SAMPLES. TOTAL
PCB CONCENTRATIONS RANGED FROM 0.53 PPM AT SBSS-3 TO 32,000 PPM AT
SBSS-7. NINE SURFACE SOIL SAMPLES HAVE PCB CONCENTRATIONS EXCEEDING 50
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PPM. EIGHT OF THESE SAMPLES ARE LOCATED AT AREAS OF WASTE DEPOSITION.
SURFACE SOIL SAMPLES SBSS-4, 7, 9 AND 11 WERE COLLECTED ADJACENT TO OR
IMMEDIATELY DOWNGRADIENT OF THE ABOVE-GROUND DISPOSAL AREA. SBSS-14 WAS
COLLECTED ADJACENT TO THE NORTH SUBSURFACE DISPOSAL AREA. SURFACE SOIL
SAMPLES SBSS-17, 18 AND 19 ARE ALL LOCATED IMMEDIATELY DOWNGRADIENT OF
THE SOUTH DISPOSAL AREA. SURFACE SOIL SAMPLE SBSS-21 (325 PPM TOTAL
PCBS) WAS COLLECTED FROM A DRAINAGE SWALE DOWNGRADIENT OF THE WASTE
AREAS IN AREA B.
VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN SBSS-7, 11, 16 AND 18
THROUGH 21. SAMPLES SBSS-7 AND SBSS-6 WERE COLLECTED AT AND
DOWNGRADIENT OF THE ABOVE-GROUND DISPOSAL AREA, RESPECTIVELY. SAMPLES
SBSS-18, 19 AND 20 WERE COLLECTED IMMEDIATELY DOWNGRADIENT OF THE SOUTH
SUBSURFACE DISPOSAL AREA. SAMPLE SBSS-21 WAS COLLECTED IN A DRAINAGE
SWALE ABOUT FIFTY FEET DOWNGRADIENT OF THE WASTE IN AREA B. THE
CONCENTRATIONS OF VOCS ARE ALL LESS THAN 1 PPM.
IN ADDITION TO WASTE SAMPLES, FIVE SUBSURFACE SOIL SAMPLES WERE
COLLECTED ADJACENT TO OR BELOW THE WASTE AND ANALYZED FOR PCBS.
ADDITIONALLY, ONE SAMPLE, SBSB-2B (8-10) WAS ANALYZED FOR THE HSL
PARAMETERS. ANALYTICAL RESULTS FOR PCBS ARE PRESENTED IN TABLE 5-47.
PARAMETERS DETECTED IN THE HSL ANALYSIS OF SBSB-2B (8-10) ARE SUMMARIZED
IN TABLE 5-48.
THREE BORINGS SBSB-1, 1A AND 1B WERE INSTALLED ADJACENT TO THE
ABOVE-GROUND DISPOSAL AREA AND SAMPLED AT 4 TO 6 FEET BELOW LAND
SURFACE. TOTAL PCB CONCENTRATIONS IN THESE SAMPLES WERE 16 PPM, 1.4 PPM
AND NONE DETECTED, RESPECTIVELY. TWO SUBSURFACE SOIL SAMPLES SBSB-2B
(6-8) AND SBSB-2B (8-10) WERE COLLECTED BELOW THE WASTE IN THE NORTH
SUBSURFACE DISPOSAL AREA. THESE SOILS HAD TOTAL PCBS CONCENTRATIONS OF
18 PPM AND 80 PPM, RESPECTIVELY. SBSB-2B (8-10) WAS THE ONLY SUBSURFACE
SOIL SAMPLE TO EXCEED 50 PPM TOTAL PCBS.
NO VOCS WERE DETECTED IN THE HSL ANALYSIS OF SBSB-2B (8-10). SEVERAL
SEMI-VOLATILE COMPOUNDS WERE DETECTED. THREE INORGANIC COMPOUNDS,
COPPER, IRON AND VANADIUM EXCEEDED THE RANGE OF CONCENTRATIONS IN TABLE
5-31. CONCENTRATIONS OF COPPER, IRON AND VANADIUM ARE MUCH HIGHER IN
THE SOILS THAN IN THE OVERLYING WASTE. THE WASTE IS NOT THE SOURCE OF
THESE COMPOUNDS TO SUBSURFACE SOILS.
TWO SUBSURFACE SOIL SAMPLES WERE ALSO COLLECTED AT 0 TO 1.5 FEET AND 1.5
TO' 3 FEET BELOW LAND SURFACE OF WELL SBMW-2 LOCATED ABOUT 60 FEET EAST
OF THE WASTE IN AREA B. THESE SAMPLES WERE ANALYZED FOR PCBS ONLY.
TOTAL PCBS DETECTED IN THESE SAMPLES ARE 16 PPM AND 16.3 PPM,
RESPECTIVELY. ANALYTICAL RESULTS ARE INCLUDED IN TABLE 5-47.
GROUND WATER SAMPLES WERE COLLECTED FROM WELLS SBMW-1, 2 AND 3 ON
OCTOBER 10, 1988 AND JANUARY 18, 1989. FIRST ROUND SAMPLES WERE
ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE, SUSPENDED SOLIDS,
ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. BECAUSE SEVERAL
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SEMI-VOLATILE COMPOUNDS WERE DETECTED IN THE HSL ANALYSIS FOR
SEMI-VOLATILE COMPOUNDS. WELL SBMW-2 WAS ALSO ANALYZED FOR ALL OF THE
HSL PARAMETERS DURING THE FIRST SAMPLING COUNT. SAMPLES WERE COLLECTED
FOR INORGANIC ANALYSIS. TABLE 5-49 SUMMARIZES ANALYTICAL RESULTS FOR
DETECTED PARAMETERS.
PCBS WERE DETECTED IN WELL SBMW-2 IN JANUARY 1989 AT 0.0023 PPM AND
0.003 PPM (DUPLICATE SAMPLE). PCBS WERE NOT DETECTED IN ANY OTHER
GROUND WATER SAMPLES FOR AREA B.
SEVERAL VOLATILE ORGANIC COMPOUNDS (1,1,1-TRICHLOROETHANE, AND
TETRACHLOROETHENE) WERE DETECTED IN GROUND WATER IN AREA B.
1,1,1-TRICHLOROETHANE WAS DETECTED IN UPGRADIENT WELL SBMW-1 (0.008 PPM)
DURING THE OCTOBER 1988 SAMPLING AND IS THE ONLY VOC DETECTED IN SBMW-1.
1,1,1-TRICHLOROETHANE, TETRACHLOROETHENE, TRICHLOROETHENE AND
1,2-DICHLOROETHENE WAS DETECTED IN SBMW-2.
TRICHLOROETHENE WAS DETECTED IN WELL SBMW-3 IN JANUARY 1989 AT 0.008
PPM. THIS COMPOUND WAS ALSO DETECTED IN THE ASSOCIATED ANALYTICAL
BLANK. SAMPLE SBMW-3 WAS ANALYZED THE SAME DAY AS SAMPLES COLLECTED
FROM WELLS IN AREA A. THE 0.008 PPM TRICHLOROETHENE DETECTED IN SBMW-3
IS SIMILAR TO THE 0.007 PPM TO 0.008 PPM DETECTED IN AREA A.
TETRACHLOROETHENE WAS ALSO DETECTED IN WELL SBMW-3 IN JANUARY 1989 AT
0.025 PPM.
WELL SBMW-2, LOCATED IMMEDIATELY DOWNGRADIENT OF THE AREA OF WASTE
DEPOSITION IN AREA B, HAD THE HIGHEST CONCENTRATION OF VOCS, 33.886-PPM
DETECTED IN OCTOBER 1988, AND 77.1 PPM (77.3 PPM IN A DUPLICATE SAMPLE)
DETECTED IN JANUARY 1989.
DURING THE FIRST SAMPLING ROUND IN OCTOBER 1988, ALL THREE WELLS WERE
ANALYZED FOR THE SEMI-VOLATILE COMPOUNDS. NO SEMI-VOLATILE COMPOUNDS
WERE DETECTED IN ANY OF THE WELLS. THEREFORE, SEMI-VOLATILES WERE NOT
INCLUDED IN THE LIST OF ANALYTICAL PARAMETERS FOR THE SECOND ROUND
SAMPLES COLLECTED IN JANUARY 1989.
DURING THE FIRST SAMPLING ROUND IN OCTOBER 1988, SAMPLES WERE OBTAINED
FROM DOWNGRADIENT WELL SBMW-3 FOR INORGANIC ANALYSIS. EIGHT COMPOUNDS
WERE DETECTED IN THE NON-FILTERED SAMPLE. INORGANIC COMPOUND
CONCENTRATIONS IN THE SAMPLE WAS LOW; THEREFORE, METALS WERE NOT
INCLUDED IN THE ANALYTICAL PARAMETERS FOR THE SECOND ROUND GROUND WATER
SAMPLES COLLECTED IN JANUARY 1989 EPA WAS NOTIFIED THAT INORGANIC,
PESTICIDE, AND SEMI-VOLATILE COMPOUNDS WOULD NOT BE INCLUDED ON THE
ANALYTICAL PARAMETER LIST FOR SECOND ROUND SAMPLES IN A LETTER DATED
JANUARY 10, 1989.
AREA C
SOIL BORINGS AND EXPLORATORY TRENCHES WERE INSTALLED AS PART OF THE
REMEDIAL INVESTIGATION TO CONFIRM ACTUAL WASTE PRESENCE AND DETERMINE
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HORIZONTAL AND VERTICAL EXTENT OF THE AREAS OF WASTE DEPOSITION.
A TOTAL OF TWENTY SOIL BORINGS WERE DRILLED. SPLIT-SPOON REFUSAL WAS
ENCOUNTERED ON TOP OF WASTE BETWEEN 1 AND 4 FEET BELOW LAND SURFACE IN
BORINGS SCSB-1, 1A, 1B, 1C, 4, 4A AND 5. TO ASSIST IN SAMPLING BELOW
THE WASTE, TRENCHES 2, 3 AND 4 WERE EXCAVATED TO REMOVE WASTE AT BORING
LOCATIONS SCSB-4, 5 AND 6. BORINGS SCSB-4T, 5T AND 6T WERE ADVANCED
THROUGH THE BOTTOM OF THE TRENCHES. WASTE WAS ALSO REMOVED AT SCSB-1
AND BORING SCSB-7T WAS DRILLED THROUGH THE BOTTOM OF THE EXCAVATION.
EXPLORATORY TRENCHES INSTALLED IN THESE AREAS, AFTER THE SOIL BORINGS
WERE DRILLED, REVEALED THE PRESENCE OF LARGE POWER FACTOR CAPACITORS IN
THE AREA OF EACH OF THESE SOIL BORINGS EXCEPT SCSB-5. WASTE, IN THE
FORM OF CAPACITOR DEBRIS (METAL, PAPER AND FOIL) WAS ENCOUNTERED BY
BORINGS SCSB-1, SCSB-1E, 5A AND 6C. WASTE WAS NOT OBSERVED IN THE
REMAINING TWELVE SOIL BORINGS.
FOLLOWING INSTALLATION OF THE SOIL BORINGS, FIFTEEN EXPLORATORY TRENCHES
WERE INSTALLED TO FURTHER DETERMINE THE HORIZONTAL AND VERTICAL EXTENT
OF THE TWO AREAS OF WASTE DEPOSITION. EXPLORATORY TRENCHES WERE
EXCAVATED WITH A BACKHOE AND VISUALLY DESCRIBED BY THE ON-SITE RMT
GEOLOGIST.
THE HORIZONTAL EXTENT OF THE TWO AREAS OF WASTE DEPOSITION WAS
DETERMINED BY SOIL BORINGS AND EXPLORATORY TRENCHES. WASTE IN AREA C IS
DISPOSED IN TWO PARALLEL TRENCHES ORIENTED IN A NORTHEAST DIRECTION.
THE NORTHWEST TRENCH IS 120 FEET LONG AND 5 FEET WIDE. THE SOUTHEAST
TRENCH IS 45 FEET LONG AND 12 FEET WIDE. LARGE POWER FACTOR CAPACITORS
ARE PRESENT IN THE SOUTHEAST WASTE AREA. CAPACITOR PAPER, FOIL, METAL
BANDING, AND POWER FACTOR CAPACITORS ARE PRESENT IN THE NORTHWEST WASTE
DEPOSITION AREA. THE NORTHWEST WASTE AREA HAS AN APPROXIMATE SURFACE
AREA OF 65 SQUARE YARDS AND THE SOUTHEAST AREA HAS AN APPROXIMATE
SURFACE AREA OF 60 SQUARE YARDS. TOTAL WASTE VOLUME AT AREA C IS
APPROXIMATELY 200 CUBIC YARDS.
A SAMPLE OF WASTE COLLECTED FROM SOIL BORING SCSB-6C AT 0.0 TO 2.0 FEET
BELOW LAND SURFACE, AND A COMPOSITE SAMPLE OF WASTE COLLECTED FROM
EXPLORATORY TRENCHES SCST-2, 3, AND 4, WERE ANALYZED FOR THE HSL
PARAMETERS (SAMPLES OF WASTE FOR VOC ANALYSIS WERE COLLECTED FROM
EXPLORATORY TRENCHES SCST-2, 3 AND 4 WERE ANALYZED SEPARATELY, (NOT
COMPOSITED). ANALYTICAL RESULTS FOR WASTE ARE PRESENTED ON TABLE 5-50.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN THE WASTE. HOWEVER,
THE CONCENTRATIONS OF VOCS DETECTED ARE NEAR THE DETECTION LIMITS.
TRICHLOROETHENE WAS THE MOST COMMONLY FOUND CONSTITUENT.
NO SEMI-VOLATILE OR PESTICIDE COMPOUNDS WERE DETECTED IN THE WASTE IN
AREA C.
PCBS WERE DETECTED IN BOTH WASTE SAMPLES SCSB-6C (0.0-2.0) AND SCST-2,
3, 4 AT 38,000 PPM AND 25,000 PPM TOTAL PCBS.
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THE INORGANIC COMPOUND COPPER WAS THE ONLY COMPOUND DETECTED IN THE
WASTE WITH CONCENTRATIONS ABOVE THE RANGE OF CONCENTRATIONS IN TABLE
5-31.
SEVENTEEN SURFACE SOIL SAMPLES (SCSS-1 THROUGH SCSS-17) WERE COLLECTED.
SCSS-1 WAS ANALYZED FOR THE HSL PARAMETERS. SAMPLES SCSS-2 THROUGH
SCSS-17 WERE ANALYZED FOR PCBS ONLY. TABLE 5-51 SUMMARIZES PARAMETERS
DETECTED IN SCSS-1. PCB CONCENTRATIONS ARE SUMMARIZED IN TABLE 5-52.
TOTAL PCB CONCENTRATIONS RANGED FROM NONE DETECTED AT SAMPLE SITE SCSS-4
TO 11,000 PPM DETECTED AT SCSS-7. ONLY SEVEN SAMPLES (SCSS-5, 7, 8, 9,
11, 12 AND 13) HAD PCB CONCENTRATIONS GREATER THAN 50 PPM. THESE
SAMPLES WERE GROUPED TOGETHER AND LOCATED ALONG AND IMMEDIATELY
DOWNGRADIENT AT THE NORTHWEST TRENCH.
IN ADDITION TO COMPOSITE WASTE SAMPLE SCST-2, 3 AND 4, AND WASTE SAMPLE
SCSB-6C (0-2), TWENTY-THREE SUBSURFACE SOIL SAMPLES WERE COLLECTED AND
ANALYZED. THREE SAMPLES, SCSB-5 (5-6.5) SCSB-5A (7.5-9) AND SCST-1 WERE
ANALYZED FOR THE HSL PARAMETERS. THE REMAINING TWENTY SAMPLES WERE
ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS FOR PCBS ARE PRESENTED IN
TABLE 5-53. ADDITIONAL PARAMETERS DETECTED IN THE HSL ANALYSES ARE
PRESENTED IN TABLE 5-54.
PCBS WERE DETECTED IN ALL SUBSURFACE SOIL SAMPLES, EXCEPT SCSB-6A (4-6),
COLLECTED ADJACENT TO THE NORTHWEST WASTE AREA. OF THE REMAINING SOIL
SAMPLES, TWELVE HAD TOTAL PCB CONCENTRATIONS GREATER THAN 50 PPM.
SAMPLES SCSB-1D (4-6), WITH A TOTAL PCB CONCENTRATION OF 214 PPM, WAS
COLLECTED NEAR THE SOUTH END OF THE SOUTHEAST WASTE AREA. THE REMAINING
TEN SAMPLES WITH GREATER THAN 50 PPM TOTAL PCBS WERE COLLECTED FROM
BELOW THE WASTE, RANGING FROM 90 PPM AT SCSB-1E (8-9.5), SCSB-1E
(10-11.5), SCSB-7T (7-8.5) AND SCSB-7T (9.5-11), WERE COLLECTED BELOW
THE WASTE IN THE SOUTHWEST WASTE AREA. TOTAL PCB CONCENTRATIONS IN BOTH
BORINGS DECREASED IN CONCENTRATION FROM 90 PPM TO 35 PPM IN SCSB-1E AND
FROM 9,303 PPM TO 900 PPM AT BORING SCSB-7T. TOTAL PCBS DETECTED IN
SOILS COLLECTED FROM BORING SCSB-6C INCREASED WITH DEPTH FROM 320 PPM TO
4,570 PPM. THE OTHER FOUR BORINGS DEMONSTRATED DECREASES IN TOTAL PCB
CONCENTRATIONS IN DEPTH FROM 6,400 PPM TO 1.42 PPM AT SCSB-4T, 7,800 PPM
TO 5.8 PPM AT SCSB-5T, 14, 100 PPM TO 3.9 PPM AT SCSB-5A AND 33,000 TO
24,000 AT SCSB-6T. AS SHOWN, THREE OF THESE BORINGS DECREASED IN PCB
CONCENTRATIONS TO LESS THAN 50 PPM.
THE SUBSURFACE SOIL SAMPLES COLLECTED FROM BORINGS SCSB-2,3,6,6A AND 6B
WERE COLLECTED OUTSIDE OF THE WASTE AREAS. TOTAL PCB CONCENTRATIONS IN
THESE SAMPLES RANGED FROM NONE DETECTED TO 10 PPM. TWO SUBSURFACE SOIL
SAMPLES WERE COLLECTED AT 0.5 TO 2 FEET BELOW LAND SURFACE AND 2 TO 3.5
FEET BELOW LAND SURFACE OF WELL SCMWB-5, AND ANALYZED FOR PCBS. TOTAL
PCB CONCENTRATIONS FOR SCWMB-5 (0.5-2) WERE 1.60 PPM AND 1.13 PPM
(DUPLICATE SAMPLE). SAMPLE SCMWB-5 (2-3.5) HAD A TOTAL PCB
CONCENTRATION OF 0.93 PPM.
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NO VOCS WERE DETECTED IN SAMPLES SCSB-5 (5-6.5) AND SCSB-5A (7.5-9)
COLLECTED BELOW THE NORTHWEST WASTE AREA.
SEMI-VOLATILE ORGANIC COMPOUNDS AND PESTICIDE COMPOUNDS WERE NOT
DETECTED IN ALL THREE SAMPLES. SEVERAL INORGANIC COMPOUNDS WERE
DETECTED IN SAMPLES SCSB-5 (5-6.5), SCSB-5A (7.5-9) AND SCST-1. NONE OF
THE CONCENTRATIONS DETECTED EXCEEDED THE RANGE OF CONCENTRATIONS IN
TABLES 5-30 AND 5-31.
GROUND WATER SAMPLES WERE COLLECTED FROM WELL SCMW-5. THE SAMPLE WAS
ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE, SUSPENDED SOLIDS,
ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. TABLE 5-54 PRESENTS
ANALYTICAL RESULTS FOR BOTH SAMPLING ROUNDS.
PCBS WERE DETECTED IN WELL SCMW-5 AT A CONCENTRATION OF 0.0075 PPM ON
OCTOBER 20, 1988 AND 0.0058 PPM ON JANUARY 17, 1989.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN GROUND WATER IN AREA
C. TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE MOST COMMON COMPOUNDS
AND WERE DETECTED IN TEN WELLS.
TOTAL VOC CONCENTRATIONS IN THESE TEN WELLS FOR BOTH SAMPLING ROUNDS ARE
INCLUDED ON TABLE 5-55. THE WELL (SCMW-5) HAD MUCH LOWER TOTAL VOC
CONCENTRATIONS THAN OTHER AREA WELL WATER SAMPLES.
AREA D
SOIL BORINGS WERE INSTALLED AS PART OF THE REMEDIAL INVESTIGATION TO
CONFIRM ACTUAL WASTE PRESENCE AND TO INVESTIGATE HORIZONTAL AND VERTICAL
EXTENT OF THE AREA OF WASTE DEPOSITION. TWELVE TOTAL BORINGS WERE
ATTEMPTED AT SEVEN LOCATIONS PROPOSED IN THE WORK PLAN. ALL OF THE
BORINGS (EXCEPT SDSB-2,8 AND 10) ARE LOCATED IN AREAS OF SUSPECTED WASTE
DEPOSITION. TWO BORINGS WERE INSTALLED IN THE AREA OF SDSB-4, AND THREE
BORINGS WERE ATTEMPTED IN THE AREA OF BOTH SDSB-1 AND SDSB-5. BURIED
DRUMS WERE ENCOUNTERED WHILE BORING IN THE AREA OF SDSB-1 AND SDSB-4.
SUBSURFACE SOIL SAMPLING WAS TERMINATED TO AVOID THE RISK OF PUNCTURING
DRUMS.
SOIL BORING LOCATIONS ARE SHOWN ON PLATE 3-8, AND LITHOLOGIC LOGS.
WASTE, IN THE FORM OF SEMI-SOLID TO SOLID RESINOUS MATERIAL, WAS
OBSERVED IN BORINGS SDSB-1B, 4, 4A, AND 7. WASTE WAS NOT OBSERVED IN
THE EIGHT REMAINING SOIL BORINGS; HOWEVER, SPLIT-SPOON REFUSAL WAS
ENCOUNTERED AT 0.5 FEET BELOW LAND SURFACE IN SDSB-1 AND A VOID WAS
ENCOUNTERED AT 3.0 TO 4.5 FEET BELOW LAND SURFACE IN SDSB-1A, INDICATING
THAT WASTE MAY BE PRESENT IN THESE AREAS.
SINCE THE SOIL BORING PROGRAM COULD NOT BE COMPLETED, THE VERTICAL
EXTENT OF WASTE IS UNKNOWN, AND THE HORIZONTAL EXTENT OF THE WASTE HAS
BEEN ESTIMATED BASED ON MAGNETIC ANOMALIES DETECTED IN THE PRELIMINARY
INVESTIGATION. WASTE IN AREA D HAS AN APPROXIMATE SURFACE AREA OF 1,350
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SQUARE YARDS. BASED ON A WASTE THICKNESS OF 10 FEET THERE COULD BE
4,500 CUBIC YARDS OF WASTE.
AFTER THE BORING PROGRAM WAS TERMINATED AN EXPLORATORY TRENCHING PROGRAM
WAS INITIATED. SEVERAL DRUMS WERE UNCOVERED LESS THAN THREE FEET BELOW
LAND SURFACE IN THE FIRST TRENCH. EXPLORATORY TRENCHING WAS THEN
DISCONTINUED TO AVOID PUNCTURING THE DRUMS. A SAMPLE OF SOIL DESIGNATED
SDSB-1 WAS TAKEN FROM THE EXCAVATION AND ANALYZED FOR THE HSL
PARAMETERS. WASTE COLLECTED FROM SDSB-7 AT 2.0 TO 2.8 FEET BELOW LAND
ANALYTICAL RESULTS FOR PARAMETERS DETECTED IN THE WASTE.
SEVERAL VOLATILE ORGANIC COMPOUNDS, WERE DETECTED IN WASTE FOUND IN AREA
D. TRICHLOROETHENE AND TETRACHLOROETHENE WERE PREVALENT. NO
SEMI-VOLATILE OR PESTICIDE COMPOUNDS WERE DETECTED IN THE WASTE.
TOTAL PCBS DETECTED IN SDSB-1 (SURFACE) WERE 77,800 PPM. THIS SOIL
SAMPLE WAS COLLECTED IN AN AREA OF SPILLED LIQUID DURING ONE BACKHOE
EXCAVATION.
ALUMINUM, ARSENIC, IRON, AND VANADIUM WERE THE ONLY INORGANIC COMPOUNDS
FOUND IN THE WASTE AT CONCENTRATIONS ABOVE THE RANGE IN TABLE 5-31.
SURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED FOR PCBS AND VOCS TO
DETERMINE THE EXTENT OF THESE CONSTITUENTS ON THE LAND SURFACE.
FORTY-FOUR SURFACE SOIL SAMPLES (SDSS-1 THROUGH SDSS-44) WERE COLLECTED.
IN ADDITION TO PCBS AND VOCS, SAMPLE SDSS-1 WAS ANALYZED FOR THE HSL
PARAMETERS. TABLE 5-58 SUMMARIZES PARAMETERS DETECTED IN SDSS-1.
ANALYTICAL RESULTS FOR PCBS AND VOCS ARE SUMMARIZED ON TABLE 5-59.
TOTAL PCB CONCENTRATIONS ARE ALSO SHOWN ON PLATE 3-13. TOTAL PCB
CONCENTRATIONS RANGED FROM NONE DETECTED IN SAMPLE 5055-20 TO 1,010 PPM
IN SAMPLE SDSS-11. ONLY TWELVE SAMPLES, (SDSS-2, 3, 4, 6, 7, 11, 18,
21, 22, 24, 29, AND 42) EXCEEDED 50 PPM TOTAL PCBS. THESE SAMPLES ARE
GROUPED INTO TWO AREAS LOCATED AT THE EASTERN AND SOUTHERN PORTIONS OF
AREA 0.
VOCS WERE DETECTED IN SEVEN SAMPLES (SDSS-4, 6, 7, 14, 17, 18 AND 29).
TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE MOST COMMON COMPOUNDS
DETECTED. TOTAL VOC CONCENTRATIONS IN THESE SEVEN SAMPLES RANGE FROM
0.007 PPM TO 0.4 PPM. SURFACE SOIL SAMPLES SDSS-4, 6, 7, 14 AND 17 ARE
GROUPED TOGETHER AT THE EAST END OF AREA D.
SUBSURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE
EXTENT OF PCBS BELOW LAND SURFACE AND BELOW THE WASTE. SUBSURFACE SOIL
SAMPLING WAS TERMINATED AFTER DRUMS WERE DISCOVERED. TWELVE SOIL
BORINGS WERE DRILLED. BORINGS SDSB-2, 5, 5A, 5B, 8 AND 10 DID NOT
PENETRATE WASTE. ONE SOIL SAMPLE WAS COLLECTED FROM EACH BORING AND
ANALYZED FOR PCBS. ANALYTICAL RESULTS ARE SUMMARIZED ON TABLE 5-60.
PCB CONCENTRATIONS DETECTED WERE LOW, RANGING FROM 0.24 PPM TO 8.9 PPM.
BORING SDSB-1A PENETRATED WASTE, AND SOIL SAMPLE SDSB-1A (5-6) WAS
COLLECTED BELOW THE WASTE AND ANALYZED FOR HSL PARAMETERS. ANALYTICAL
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RESULTS ARE PRESENTED IN TABLE 5-61.
(5-6) WAS 360 PPM.
TOTAL PCBS DETECTED IN SDSB-1A
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED OF WHICH
TRICHLOROETHENE WAS THE PRIMARY CONSTITUENT. BIS (2-ETHYLHEXYL)
PHTHALATE WAS THE ONLY SEMI-VOLATILE COMPOUND DETECTED. PESTICIDE
COMPOUNDS WERE NOT DETECTED. NONE OF THE INORGANIC COMPOUNDS EXCEEDED
THE RANGE OF CONCENTRATIONS IN TABLES 5-30 AND 5-31.
IN ADDITION TO SOIL BORINGS IN THE VICINITY OF THE WASTE, TWO SOIL
SAMPLES WERE COLLECTED AT EACH OF THE FOUR MONITORING WELL LOCATIONS
(SDWB-1 THROUGH 4) AT 0 TO 1.5 FEET BELOW LAND SURFACE AND 1.5 TO 3 FEET
BELOW LAND SURFACE. THESE SAMPLES WERE ANALYZED FOR PCBS. NO PCBS WERE
DETECTED AT SDWB-2. SAMPLE SDWB-1 (0-1.5) HAD A CONCENTRATION OF 113
PPM JUST BELOW THE LAND SURFACE LAND SURFACE (0-1.5 FEET). HOWEVER, THE
SAMPLE DIRECTLY BELOW HAD A PCB CONCENTRATION OF 1.3 PPM. THE
CONCENTRATION IN THE UNDERLYING SOIL SDWB-3 (1.5-3) WAS 0.290 PPM.
TOTAL PCB CONCENTRATIONS AT SDWB-4 INCREASED WITH DEPTH FROM 2 PPM AT
SDWB-4 (0-1.5) TO 23.9 PPM IN SDWB-4 (1.5-3).
GROUND WATER SAMPLES WERE COLLECTED FROM WELLS SDMW-1,2,3,4. THE TWO
SAMPLING ROUNDS WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE,
SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. TABLE
5-55 PRESENTS ANALYTICAL RESULTS FOR BOTH SAMPLING ROUNDS.
PCBS WERE NOT DETECTED IN THE AREA D WELLS.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN GROUND WATER IN AREA
D. TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE MOST COMMON COMPOUNDS
AND WERE DETECTED IN TEN WELLS.
TOTAL VOC CONCENTRATIONS IN THESE TEN WELLS FOR BOTH SAMPLING ROUNDS ARE
INCLUDED ON TABLE 5-55. THE HIGHEST CONCENTRATIONS OF VOCS WERE
DETECTED IN AREA D RANGING FROM 0.356 PPM TO 90.8 PPM.
AREA E
SOIL BORINGS WERE INSTALLED AS PART OF THE REMEDIAL INVESTIGATION TO
DETERMINE IF WASTE IS PRESENT IN AREA E. THREE SOIL BORINGS, SESB-1, 2
AND 3, WERE INSTALLED IN AREA E AT LOCATIONS SHOWN ON PLATE 3-6. TOTAL
DEPTHS OF BORINGS WERE 16 FEET BELOW LAND SURFACE FOR SESB-1, 15 FEET
BELOW LAND SURFACE FOR SESB-2, AND 12-FEET BELOW LAND SURFACE AT SESB-3.
EACH OF THE BORINGS WERE TERMINATED AT LEAST FOUR FEET INTO SAPROLITE
(AS DEFINED BY REMNANT ROCK STRUCTURE). NO WASTE WAS FOUND IN ANY OF
THE BORINGS IN AREA E. CONSEQUENTLY, NO WASTE SAMPLES WERE COLLECTED.
SUBSURFACE SOILS WERE COLLECTED FROM THREE SOIL BORINGS IN AREA E TO
DETERMINE IF PCBS ARE PRESENT. ONE SOIL SAMPLE FROM EACH BORING WAS
COLLECTED AND ANALYZED FOR PCBS. ANALYTICAL RESULTS ARE PRESENTED IN
TABLE 5-62. SAMPLE DEPTHS RANGED FROM 3.5 TO 7 FEET BELOW LAND SURFACE.
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PCB CONCENTRATIONS WERE LOW, RANGING FROM 0.26 TO 14 PPM.
PAVED, THEREFORE NO SURFACE SOIL SAMPLES WERE COLLECTED.
AREA E IS
GROUND WATER SAMPLES WERE OBTAINED FROM WELL SEMW-1. FIRST ROUND
SAMPLES WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE,
SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. SAMPLES
WERE COLLECTED FOR INORGANICS ANALYSIS. TABLE 5-63 SUMMARIZES
ANALYTICAL RESULTS FOR DETECTED PARAMETERS. SECOND ROUND GROUND WATER
SAMPLES WERE ANALYZED FOR VOCS, PCBS, PH, SPECIFIC CONDUCTANCE,
SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATES.
PCBS WERE DETECTED IN WELLS SWMW-2,3,4,5,6,7 AND 7A IN BOTH SAMPLING
ROUNDS WITH TOTAL PCB CONCENTRATIONS RANGING FROM 0.0032 PPM AT SWMW-3
(JANUARY 1989) TO 0.11 PPM IN WELL SWMW-5, ALSO IN JANUARY, 1989. PCBS
WERE DETECTED IN WELL SWMW-8 AND 9 ONLY IN THE SECOND ROUND OF SAMPLES
WITH TOTAL PCB CONCENTRATIONS OF 0.014 PPM AND 0.038 PPM, RESPECTIVELY.
PCBS WERE NOT DETECTED IN AREA E WELL SEMW-1 OR UPGRADIENT WELL SWMW-1
FOR THE WASTEWATER TREATMENT FACILITY.
SEVERAL VOLATILE ORGANIC COMPOUNDS (CHLOROFORM, 1,1-DICHLOROETHANE,
1,1-TRICHLOROETHANE, CARBON TETRACHLORIDE, TRICHLOROETHANE, AND
TETRACHLOROETHANE) WERE DETECTED IN WELL SEMW-1 LOCATED IN AREA E,
UPGRADIENT OF THE WASTEWATER TREATMENT FACILITY. TOTAL VOCS (EXCLUDING
ACETONE) DETECTED IN SEMW-1 WERE 0.10 PPM (OCTOBER 1988) AND 0.107 PPM
(JANUARY 1989).
IN THE WASTEWATER TREATMENT FACILITY WELLS, TOTAL 1,2-DICHLOROETHENE,
TRICHLOROETHENE, AND TETRACHLOROETHENE WERE DETECTED IN WELLS SWMW-2
THROUGH SWMW-9 DURING BOTH SAMPLING EVENTS. IN ADDITION,
TRICHLOROETHENE AND TETRACHLOROETHENE WERE DETECTED IN BACKGROUND WELL
SWMW-1 DURING THE SECOND SAMPLING ROUND IN JANUARY 1989. THE
TRICHLOROETHENE CONCENTRATION DETECTED IN SWMW-1 WAS 0.007 PPM.
IN ADDITION TO TOTAL 1,2-DICHLOROETHENE, TRICHLOROETHANE AND
TETRACHLOROETHENE, SEVERAL OTHER VOCS (VINYL CHLORIDE,
1,1-DICHLOROETHENE, 1,1-DICHLOROETHANE, CHLOROFORM,
1,2-DICHLOROETHANE, CARBON TETRACHLORIDE AND BENZENE) WERE DETECTED AT
LESS FREQUENT OCCURRENCES.
TOTAL VOC CONCENTRATIONS AND ARE INCLUDED IN TABLE 5-63. TOTAL VOC
CONCENTRATIONS RANGED FROM NONE DETECTED DURING THE FIRST SAMPLING ROUND
IN WELL SWMW-1 TO 3.306 PPM IN WELL SWMW-2 IN OCTOBER 1988.
TOTAL VOC CONCENTRATIONS IN WELL SWMW-9, LOCATED IMMEDIATELY UPGRADIENT
OF THE INACTIVE LAGOON, AND WELLS SWMW-2 AND 3, LOCATED IMMEDIATELY
DOWNGRADIENT OF THE INACTIVE LAGOON, RANGED FROM 0.608 PPM IN SWMW-3 TO
3.306 PPM IN SWMW-2. WELL SWMW-9 IS LOCATED APPROXIMATELY 45 FEET
UPGRADIENT OF THE INACTIVE LAGOON. THE PRESENCE OF VOCS MAY BE THE
RESULT OF DIRECT HYDROLOGIC CONNECTION (THROUGH FRACTURES) BETWEEN THE
INACTIVE LAGOON AND THE SCREENED PORTION OF WELL SWMW-9. WELL SWMW-4,
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LOCATED DOWNGRADIENT OF THE INACTIVE LAGOON AND IMMEDIATELY UPGRADIENT
OF THE STABILIZATION LAGOON, HAD TOTAL VOC CONCENTRATIONS OF 1.101 PPM,
1.86 PPM AND 1.95 PPM (DUPLICATE SAMPLE). TOTAL VOCS IN WATER TABLE
WELLS SWMW-5,6,7 AND 8 RANGED FROM 0.095 PPM IN SWMW-8 TO 2.15 PPM IN
SWMW-5 AND SHOW DECREASES IN CONCENTRATION, WITH DISTANCE DOWNGRADIENT
FROM THE STABILIZATION LAGOON; HOWEVER, WELL SWMW-7A, SCREENED BELOW THE
WATER TABLE ON TOP OF BEDROCK, HAD HIGHER TOTAL VOC CONCENTRATIONS THAN
ADJACENT WATER TABLE WELL SWMW-7. DETECTED CONCENTRATIONS IN SWMW-7A
(1.96 PPM AND 2.57 PPM) WERE THE HIGHEST OF THE FIVE DOWNGRADIENT WELLS
FOR THE RESPECTIVE SAMPLING PERIODS.
DURING THE FIRST ROUND SAMPLING IN OCTOBER 1988, WELLS SWMW 4 AND SWMW-6
WERE ANALYZED FOR SEMI-VOLATILE AND PESTICIDE ORGANIC COMPOUNDS. NO
SEMI-VOLATILE COMPOUNDS WERE DETECTED. HEPTACHLOR EPOXIDE WAS THE ONLY
PESTICIDE ORGANIC COMPOUND DETECTED IN SWMW-4 (0.00021 PPM) AND LOW
CONCENTRATIONS. SEMI-VOLATILE AND PESTICIDE ORGANICS COMPOUNDS WERE NOT
INCLUDED IN- THE LIST OF ANALYTICAL PARAMETERS FOR SECOND ROUND SAMPLES
COLLECTED IN JANUARY 1989.
IN OCTOBER 1988, SAMPLES WERE OBTAINED FROM DOWNGRADIENT WELL SWMW-4 AND
6 FOR INORGANIC COMPOUND ANALYSIS. TWELVE COMPOUNDS WERE DETECTED IN
THE SAMPLE FOR WELL SWMW-4 (SEE TABLE 5-63). TEN INORGANIC COMPOUNDS
WERE DETECTED IN THE SAMPLE FOR SWMW-6. CONCENTRATIONS IN BOTH THE
SAMPLES WERE LOW, THEREFORE, METALS WERE NOT INCLUDED IN THE ANALYTICAL
PARAMETERS FOR THE SECOND ROUND GROUND WATER SAMPLES COLLECTED IN
JANUARY 1989.
EPA WAS NOTIFIED OF THE ELIMINATION OF INORGANIC, SEMI-VOLATILE, AND
PESTICIDE ORGANIC COMPOUNDS FROM THE ANALYTICAL PARAMETER LIST FOR
SECOND ROUND SAMPLES IN A LETTER DATED JANUARY 10, 1989.
AREA F
SOIL BORINGS AND EXPLORATORY TRENCHES WERE INSTALLED AS PART OF THE
REMEDIAL INVESTIGATION TO DETERMINE IF WASTE WAS PRESENT, AND TO
DETERMINE THE HORIZONTAL AND VERTICAL EXTENT OF WASTE.
A TOTAL OF SIX SOIL BORINGS WERE DRILLED IN AREA F.
SOIL BORING LOCATIONS ARE SHOWN ON PLATE 3-8. ALUMINUM HYDROXIDE SLUDGE
WAS FOUND IN BORINGS SFSB-2 AND 2A. SLUDGE WAS ALSO FOUND IN THE AREA
OFF BORING SFSB-3. NO WASTE WAS FOUND IN BORINGS SFSB-1, 1A AND 1B.
FOLLOWING THE INSTALLATION OF SOIL BORINGS, NINE EXPLORATORY TRENCHES
WERE EXCAVATED TO FURTHER DETERMINE THE VERTICAL AND HORIZONTAL EXTENT
OF SLUDGE IN THE VICINITY OF SFSB-2. TRENCH LOCATIONS ARE SHOWN ON
PLATE 3-9. TRENCHES WERE EXCAVATED WITH A BACKHOE WITH DEPTHS RANGING
FROM 1.5 TO 9 FEET BELOW LAND SURFACE. THE SLUDGE IS DEPOSITED IN AN
ELONGATED AREA APPROXIMATELY 23 FEET WIDE AND 75 FEET LONG COMPRISING AN
AREA OF ABOUT 180 SQUARE YARDS. CROSS SECTIONS OF THE AREA OF WASTE
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DEPOSITION ARE SHOWN ON PLATE 3-9. SLUDGE DEPOSITED IN THE VICINITY OF
SFSB-2 IS MOSTLY COVERED WITH SOIL FILL. DEPTH TO THE SLUDGE RANGES
FROM LAND SURFACE TO S FEET BELOW LAND SURFACE. SLUDGE THICKNESS RANGED
FROM 0.2 TO 5 FEET. THE ESTIMATED VOLUME OF WASTE IN AREA F IS 200
CUBIC YARDS.
A SAMPLE OF SLUDGE COLLECTED FROM SOIL BORINGS SFSB-2A AT 4 TO 6 FEET
BELOW LAND SURFACE DESIGNATED SFSB-2A (4-6) WAS ANALYZED FOR THE HSL
PARAMETERS. ANALYTICAL RESULTS ARE PRESENTED IN TABLE 5-64.
TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE ONLY VOLATILE ORGANIC
COMPOUNDS DETECTED AND HAD CONCENTRATIONS LESS THAN 1 PPM.
SEMI-VOLATILE AND PESTICIDE COMPOUNDS WERE NOT DETECTED. PCBS WERE
DETECTED IN THE WASTE WITH A TOTAL PCB CONCENTRATION OF 20,900 PPM. A
SAMPLE OF WASTE WAS ALSO COLLECTED 4 TO 6 FEET BELOW LAND SURFACE FROM A
BORE HOLE ADJACENT TO SFSB-2A DESIGNATED SFSB-2W (4-6) AND ANALYZED FOR
PCBS. AROCLORS 1248 AND 1254 WERE DETECTED WITH A TOTAL PCB
CONCENTRATION OF 16,500 PPM.
ALUMINUM WAS THE ONLY INORGANIC COMPOUND DETECTED AT CONCENTRATIONS
ABOVE THE RANGE IN TABLE 5-31.
SUBSURFACE SOILS WERE ANALYZED TO DETERMINE THE PRESENCE OF PCBS AND
OTHER CONSTITUENTS BELOW LAND SURFACE AND BELOW THE WASTE. SURFACE SOIL
SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE EXTENT OF PCBS ON
THE LAND SURFACE.
ELEVEN SURFACE SOIL SAMPLES (SFSS-1 THROUGH
WAS ANALYZED FOR THE HSL PARAMETERS. TABLE
DETECTED IN SFSS-1. SAMPLES SFSS-2 THROUGH
ONLY. PCB CONCENTRATIONS ARE SUMMARIZED IN
CONCENTRATIONS RANGED FROM NONE DETECTED IN
PPM DETECTED IN SFSS-5. ONLY FOUR SAMPLES,
50 PPM.
11) WERE COLLECTED. SFSS-1
5-65 SUMMARIZES PARAMETERS
11 WERE ANALYZED FOR PCBS
TABLE 5-66. TOTAL PCB
SOIL SAMPLES SFSS-2 TO 632
SFSS-4, S, 6 AND 9, EXCEEDED
IN ADDITION TO WASTE SAMPLES SFSB-2A (4-6) AND SFSB-2W (4-6), NINE
SUBSURFACE SOIL SAMPLES WERE COLLECTED FOR ANALYSIS. ONE SAMPLE, SFSB-2
(9.5-11.5) COLLECTED BELOW THE WASTE, WAS ANALYZED FOR THE HSL
PARAMETERS. THE REMAINING SAMPLES WERE ANALYZED FOR PCBS ONLY.
ANALYTICAL RESULTS FOR PCBS ARE PRESENTED IN TABLE 5-67. THE ADDITIONAL
PARAMETERS DETECTED IN THE HSL ANALYSIS OF SAMPLE SFSB-2 (9.5-11.5) ARE
PRESENTED IN TABLE 5-68. NONE OF THE SUBSURFACE SOIL SAMPLES HAD TOTAL
PCB CONCENTRATIONS GREATER THAN 50 PPM. BORINGS SFSB-1, 1A AND 1B WERE
DRILLED IN AN AREA OF SUSPECTED WASTE DEPOSITION. NO WASTE WAS OBSERVED
IN THESE BOREHOLES. A SOIL SAMPLE WAS COLLECTED AT 4 TO 6 FEET BELOW
LAND SURFACE IN EACH BORING AND ANALYZED FOR PCBS. TOTAL PCB
CONCENTRATIONS IN THESE SAMPLES WERE 0.077 PPM, 1.45 PPM AND NONE
DETECTED, RESPECTIVELY. BORINGS SFSB-2 AND 2A WERE DRILLED THROUGH THE
AREA OF WASTE DEPOSITION. SAMPLES SFSB-2 (8-9.5), SFSB-2 (9.5-11.5) AND
SFSB-2A (6-8), WERE COLLECTED BENEATH THE WASTE. TOTAL PCB
CONCENTRATIONS TO 3.5 FEET BELOW THE WASTE, TO 0.3 PPM IN SAMPLE SFSS-2
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(9.5-11.5), COLLECTED 3.5 TO 5.5 FEET BELOW THE WASTE. TOTAL PCB
CONCENTRATIONS IN BORING SFSB-2A DECREASED FROM 20,900 PPM DETECTED IN
THE WASTE TO 24.1 PPM DETECTED IN THE UNDERLYING SOIL SAMPLE.
SAMPLE SFSB-3 (3.5-5) WAS COLLECTED IN AN AREA WHERE NON-PCB BEARING
WASTE SLUDGE WAS DISPOSED. NO PCBS WERE DETECTED IN THIS SAMPLE.
SAMPLES SFWB-6 (0-1.5) AND SFWB(1.5-3) WERE COLLECTED AT THE BORING
LOCATION FOR WELL SFMW-6. NO PCBS WERE DETECTED IN THESE SAMPLES.
IN ADDITION TO PCBS, SUBSURFACE SOIL SAMPLE SFSB-2 (9.5-11.5) WAS
ANALYZED FOR THE HSL PARAMETERS. ANALYTICAL RESULTS FOR DETECTED
PARAMETERS ARE INCLUDED IN TABLE 5-68. ONE SEMI-VOLATILE COMPOUND, BIS
(2-ETHYLHEXYL) PHTHALATE, WAS DETECTED AT 1.5 PPM. PESTICIDES WERE NOT
DETECTED. NONE OF THE INORGANIC COMPOUNDS EXCEEDED THE RANGE OF
CONCENTRATIONS IN TABLES 5-30 AND 5-31.
GROUND WATER SAMPLES WERE COLLECTED FROM WELL SFMW-6. BOTH SAMPLING
ROUNDS WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE, SUSPENDED
SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. TABLE 5-55
PRESENTS ANALYTICAL RESULTS FOR BOTH SAMPLING ROUNDS.
PCBS WERE NOT DETECTED IN THE AREA F WELL.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN GROUND WATER IN AREA
F. TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE MOST COMMON COMPOUNDS
AND WERE DETECTED IN TEN WELLS.
TOTAL VOC CONCENTRATIONS IN THESE TEN WELLS FOR BOTH SAMPLING ROUNDS ARE
INCLUDED ON TABLE 5-55 AND SHOWN ON PLATE 3-15. THE WELL HAD MUCH LOWER
TOTAL VOC CONCENTRATIONS THAN THE OTHER AREA WELL SAMPLES.
AREA G
PRELIMINARY CONSTITUENT SOURCE INVESTIGATIONS WERE PERFORMED AND
SUSPECTED AREAS OF WASTE DEPOSITION WERE IDENTIFIED. TWENTY-SEVEN SOIL
BORINGS WERE DRILLED TO DETERMINE THE VERTICAL AND HORIZONTAL EXTENT OF
WASTE, IF PRESENT. NONE OF THE BORINGS PENETRATED WASTE. SOIL BORING
LOCATIONS ARE SHOWN ON PLATE 3-8. SOIL BORING DEPTHS RANGED FROM FIVE
TO SIX FEET BELOW LAND SURFACE. THERE WERE NO VISIBLE WASTE PRESENT IN
ANY OF THE SOIL BORINGS. THREE TRENCHES, SGST-1, 2 AND 3, WERE
EXCAVATED WITH A BACKHOE TO VERIFY THAT WASTE IS NOT PRESENT IN AREA G.
TRENCHES SGST-1 AND 2 ARE 70 AND 59 FEET LONG, RESPECTIVELY, AND
TRANSECT AREA G ACROSS SUSPECTED AREAS OF WASTE DEPOSITION IDENTIFIED IN
THE RI WORK PLAN. TRENCH SGST-3 WAS EXCAVATED ACROSS A BERM LOCATED AT
THE EAST END OF AREA G. NO VISIBLE SIGNS OF WASTE WERE OBSERVED IN THE
TRENCHES.
SUBSURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE IF PCBS
ARE PRESENT BELOW LAND SURFACE. SURFACE SOIL SAMPLES WERE COLLECTED TO
DETERMINE THE EXTENT OF PCBS ON THE LAND SURFACE.
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TWENTY-NINE SURFACE SOIL SAMPLES (SGSS-1 THROUGH 29) WERE COLLECTED AT
LOCATIONS SHOWN ON PLATE 3-13. SGSS-1 WAS ANALYZED FOR THE HSL
PARAMETERS. PARAMETERS DETECTED IN SGSS-1 ARE SUMMARIZED IN TABLE 5-69.
SAMPLES SGSS-2 THROUGH 29 WERE ANALYZED FOR PCBS ONLY. PCB
CONCENTRATIONS ARE SUMMARIZED IN TABLE 5-70 AND PRESENTED ON PLATE
3-13. TOTAL PCB CONCENTRATIONS RANGED FROM NONE DETECTED, IN SAMPLES
SGSS-5, 7, 16, 17, 18, TO 3,800 PPM, DETECTED IN SGSS-25. ONLY FOUR
SAMPLES, SGSS-15 (50.4 PPM), SGSS-25 (3800 PPM), SGSS-26 (1500 PPM) AND
SGSS-29 (99 PPM), EXCEED 50 PPM. SAMPLE SGSS-25 WAS COLLECTED FROM AN
EARTHEN BERM THAT EXTENDS EASTWARD FROM AREA G INTO AREA H. THIS BERM
APPEARS TO HAVE BEEN FORMED AS A RESULT OF REMOVING SOIL FROM A CLEARED
AREA IN AREA H AND THE SOUTHEAST CORNER OF AREA G. SAMPLE SGSS-26 IS
LOCATED IN THIS CLEARED AREA. (TEN SURFACE SOILS COLLECTED FROM THE
CLEARED AREA IN AREA H ALSO EXCEED 50 PPM TOTAL PCBS.) SURFACE SOIL
SAMPLES SGSS-15 AND SGSS-29 ARE LOCATED IN SEPARATE AREAS, AND ARE
LOCATED IN THE VICINITY OF SAMPLES WITH MUCH LOWER CONCENTRATIONS.
TWENTY-FOUR SUBSURFACE SOIL SAMPLES WERE COLLECTED TO DETERMINE THE
PRESENCE OF PCBS AND OTHER CONSTITUENTS IN SUBSURFACE SOILS. TWO
SAMPLES, SGSB-5 (4-6) AND TRENCH 3 (2.5-4), WERE ANALYZED FOR THE HSL
PARAMETERS. THE REMAINING SAMPLES WERE ANALYZED FOR PCBS ONLY.
ANALYTICAL RESULTS FOR PCBS ARE PRESENTED IN TABLE 5-71. ADDITIONAL
PARAMETERS DETECTED IN THE HSL ANALYSIS ARE SUMMARIZED IN TABLE 5-72.
PCBS WERE DETECTED IN ONLY SEVEN OF THE TWENTY-FOUR SAMPLES COLLECTED.
SAMPLES SGSB-11 (4-6), SGSB-11A (4-6) AND TRENCH 3 (2.5-6) HAD TOTAL PCB
CONCENTRATIONS OF 74 PPM, 7,000 PPM AND 8,000 PPM AND ARE THE ONLY
SAMPLES THAT EXCEEDED 50 PPM TOTAL PCBS. THESE THREE SAMPLES WERE
COLLECTED FROM THE BERM.
TABLE 5-73 SUMMARIZES ANALYTICAL RESULTS FOR PARAMETERS OTHER THAN PCBS
DETECTED IN THE HSL ANALYSIS OF SAMPLES TRENCH-3 (2.5-4) AND SGSB-5
(4-6). SEMI-VOLATILE AND PESTICIDE ORGANIC COMPOUNDS TRICHLOROETHENE
AND TETRACHLOROETHENE WERE DETECTED IN SAMPLE TRENCH-3 (2.5-4). THESE
COMPOUNDS WERE ALSO DETECTED IN THE ASSOCIATED ANALYTICAL BLANK SAMPLES.
THE INORGANIC COMPOUND COPPER EXCEEDED THE RANGE OF CONCENTRATIONS ON
TABLES 5-30 AND 5-31. SILVER WAS ONLY 0.1 PPM ABOVE THE RANGE OF
CONCENTRATIONS ON TABLE 5-30. THE SILVER CONCENTRATIONS MAY REFLECT
NATURALLY OCCURRING CONCENTRATIONS.
TWO ADDITIONAL SUBSURFACE SOIL SAMPLES WERE COLLECTED AT 0 TO 1.5 FEE
BELOW LAND SURFACE AND 1.5 TO 3 FEET BELOW LAND SURFACE AT WELL BORINGS
FOR WELLS SGMW-7, 8 AND 9. THESE SAMPLES WERE ANALYZED FOR PCBS ONLY.
ONE SAMPLE, SGMW-7 (0-1.5), HAD A TOTAL PCB CONCENTRATION OF 0.037 PPM,
AND IS THE ONLY WELL BORING SAMPLE IN WHICH PCBS WERE DETECTED.
GROUND WATER SAMPLES WERE COLLECTED FROM WELLS SGMW-7, 8, 9. BOTH
SAMPLING ROUNDS WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE,
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SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE.
5-55 PRESENTS ANALYTICAL RESULTS FOR BOTH SAMPLING ROUNDS.
TABLE
PCBS WERE NOT DETECTED IN THE AREA G WELLS.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN GROUND WATER IN AREA
G. TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE MOST COMMON COMPOUNDS
AND WERE DETECTED IN TEN WELLS.
TOTAL VOC CONCENTRATIONS IN THESE TEN WELLS FOR BOTH SAMPLING ROUNDS ARE
INCLUDED ON TABLE 5-55. THE REMAINING WELLS (SGMW-7,8 AND 9) HAD MUCH
LOWER TOTAL VOC CONCENTRATIONS THAN THE OTHER AREAS WELLS.
AREA H
PRELIMINARY CONSTITUENT SOURCE INVESTIGATIONS WERE PERFORMED AND
SUSPECTED AREAS OF WASTE DEPOSITION WERE IDENTIFIED. THIRTEEN SOIL
BORINGS WERE DRILLED IN AREA H TO LOCATE WASTE. SOIL BORING DEPTHS
RANGED FROM FOUR TO SIX FEET BELOW LAND SURFACE. NO VISIBLE WASTES WERE
FOUND IN ANY OF THE SOIL BORINGS. TWENTY-ONE EXPLORATORY TRENCHES WERE
EXCAVATED WITH A BACKHOE TO DETERMINE THE PRESENCE OF WASTE IN AREA H.
TRENCH LENGTHS RANGED FROM 4 TO 80 FEET AND TRANSECT ACROSS MAGNETIC AND
TOPOGRAPHIC ANOMALIES ON THE LAND SURFACE. WASTE WAS FOUND IN ONLY ONE
TRENCH, SHST-6. LESS THAN ONE CUBIC YARD OF WASTE IN THE FORM OF
CAPACITOR DEBRIS WAS PRESENT.
A SAMPLE OF WASTE WAS COLLECTED FROM TRENCH SHST-6 AND ANALYZED FOR HSL
PARAMETERS. ANALYTICAL RESULTS ARE SHOWN ON TABLE 5-73. ONLY ONE
VOLATILE ORGANIC COMPOUND, TOTAL XYLENE, AND ONLY ONE SEMI-VOLATILE
COMPOUND, BIS (2-ETHYLHEXYL) PHTHALATE WERE DETECTED. PESTICIDE
COMPOUNDS WERE NOT DETECTED. A TOTAL PCB CONCENTRATION OF 2.16 PPM WAS
DETECTED IN THE WASTE. SIX INORGANIC COMPOUNDS, ALUMINUM, ARSENIC,
CADMIUM, COPPER, SILVER, AND ZINC WERE ABOVE THE RANGE OF CONCENTRATIONS
IN TABLE 5-30. THE ZINC CONCENTRATION WAS WITHIN THE RANGE OF
CONCENTRATIONS IN TABLE 5-31.
SURFACE SOIL SAMPLES WERE COLLECTED AND ANALYZED TO DETERMINE THE EXTENT
OF PCBS ON THE LAND SURFACE. SUBSURFACE SOILS WERE ANALYZED TO
DETERMINE IF PCBS ARE PRESENT BELOW LAND SURFACE. TWENTY-EIGHT SURFACE
SOIL SAMPLES (SHSS-1 THROUGH 28) WERE COLLECTED. SHSS-1 WAS ANALYZED
FOR HSL PARAMETERS. TABLE 5-74 SUMMARIZES PARAMETERS DETECTED. SAMPLES
SHSS-2 THROUGH SHSS-28 WERE ANALYZED FOR PCBS ONLY. PCB CONCENTRATIONS
ARE SUMMARIZED IN TABLE 5-75. PCBS WERE DETECTED IN TWENTY-EIGHT
SAMPLES. TOTAL PCB CONCENTRATIONS RANGED FROM 0.28 PPM AT SHSS-22 TO
8,700 PPM AT SHSS-12. TEN SAMPLES HAD TOTAL PCB CONCENTRATIONS
EXCEEDING 50 PPM. ALL TEN SAMPLES WERE COLLECTED FROM A CLEARED AREA
FROM WHICH TOPSOIL HAD APPARENTLY BEEN REMOVED IN THE CENTER OF AREA H
AND USED TO FORM A BERM ALONG THE NORTHWEST EDGE OF THE CLEARED AREA.
PCB CONCENTRATIONS IN SOILS COLLECTED NORTH AND SOUTH OF THE CLEARED
AREA HAD MUCH LOWER PCB CONCENTRATIONS.
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EIGHT SUBSURFACE SOIL SAMPLES WERE COLLECTED TO DETERMINE IF PCBS AND
OTHER CONSTITUENTS ARE PRESENT IN SUBSURFACE SOILS. SAMPLE SHSB-5 (4-5)
WAS ANALYZED FOR THE HSL PARAMETERS. THE REMAINING SAMPLES WERE
ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS FOR PCBS ARE PRESENTED IN
TABLE 5-76. ADDITIONAL PARAMETERS DETECTED IN THE HSL ANALYSIS OF
SHSB-5 (4-5) ARE PRESENTED IN TABLE 5-77. ONLY TWO SAMPLES HAD PCBS
DETECTED. SAMPLE SHSB-4 (6-8), COLLECTED IN AN EARTHEN BERM LOCATED
NORTH OF THE CLEARED AREA, HAD A TOTAL PCB CONCENTRATION OF 4.4 PPM.
SAMPLE SHSB-2 (4-5.5) COLLECTED IN THE CLEARED AREA HAD A CONCENTRATION
OF 190 PPM. THIS WAS THE ONLY SAMPLE TO EXCEED 50 PPM TOTAL PCBS.
THERE WERE NO SEMI-VOLATILE ORGANIC, PESTICIDE ORGANIC OR PCB COMPOUNDS
DETECTED IN THE HSL ANALYSIS OF SAMPLE SHSB-5B (4-5). SILVER WAS THE
ONLY INORGANIC COMPOUND TO EXCEED THE RANGE OF CONCENTRATIONS IN TABLE
5-30.
GROUND WATER SAMPLES WERE COLLECTED FROM WELL SHMW-10. BOTH SAMPLING
ROUNDS WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE, SUSPENDED
SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. TABLE 5-55
PRESENTS ANALYTICAL RESULTS FOR BOTH SAMPLING ROUNDS.
PCBS WERE NOT DETECTED IN THE AREA H WELLS.
SEVERAL VOLATILE ORGANIC COMPOUNDS WERE DETECTED IN GROUND WATER IN AREA
H. TRICHLOROETHENE AND TETRACHLOROETHENE WERE THE MOST COMMON COMPOUNDS
AND WERE DETECTED IN TEN WELLS.
TOTAL VOC CONCENTRATIONS IN THESE TEN WELLS FOR BOTH SAMPLING ROUNDS ARE
INCLUDED ON TABLE 5-55. WELL SHMW-10, LOCATED SOUTH AND DOWNGRADIENT OF
AREA H, HAD THE HIGHEST CONCENTRATIONS DETECTED ON TOP OF THE RIDGE
OUTSIDE OF AREA D.
SEPTIC DRAIN FIELD
THERE ARE THREE SEPTIC TANK DRAIN FIELDS ON THE SANGAMO WESTON PROPERTY.
TWO FIELDS ARE LOCATED ADJACENT TO EACH OTHER NORTH OF THE MANUFACTURING
FACILITY. THESE DRAIN FIELDS ARE ADDRESSED COLLECTIVELY AS THE NORTH
DRAIN FIELD. THE THIRD DRAIN FIELD IS LOCATED SOUTH OF THE
MANUFACTURING BUILDING AND IS REFERRED TO AS THE SOUTH DRAIN FIELD.
THESE DRAIN FIELDS WERE USED FOR DEPOSITION OF SANITARY WASTEWATERS FROM
THE PLANT.
SUBSURFACE SOILS WERE ANALYZED TO DETERMINE THE PRESENCE OF PCBS AND
OTHER CONSTITUENTS BELOW THE SEPTIC DRAIN FIELDS. BORINGS WERE EXTENDED
TO TWENTY FEET BELOW LAND SURFACE OR AUGER REFUSAL, WHICHEVER WAS
SHALLOWER. SOIL SAMPLES WERE RETAINED AT ABOUT FIVE FEET BELOW LAND
SURFACE, TEN FEET BELOW LAND SURFACE, AND THE BOTTOM OF THE BOREHOLE.
BORINGS SSSB-2 AND SSSB-2B ENCOUNTERED SHALLOW AUGER REFUSAL; THEREFORE,
THESE BOREHOLES WERE SAMPLED AT 4 TO 5 FEET AND 3.5 TO 4 FEET BELOW LAND
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SURFACE, RESPECTIVELY.
SOIL BORINGS SSSB-1, 2, 2B, 3C AND 4B ARE LOCATED IN THE SOUTH DRAIN
FIELD. BORINGS SSSB-5, 6C,7,9 AND 9B ARE LOCATED IN THE NORTH DRAIN
FIELD. A TOTAL OF TWENTY-FIVE SUBSURFACE SOIL SAMPLES WERE COLLECTED.
SAMPLES SSSB-4B (18-20) AND SSSB-7 (17-20) WERE ANALYZED THE HSL
PARAMETERS. THE REMAINING SAMPLES WERE ANALYZED FOR PCBS ONLY. TABLE
5-78 SUMMARIZES PCB CONCENTRATIONS DETECTED. HSL PARAMETERS DETECTED IN
SSSB-4B (18-20) AND SSSB-7 (17-20) ARE PRESENTED IN TABLE 5-79.
PCBS WERE DETECTED IN EIGHT OF THE TEN SAMPLES COLLECTED IN THE SOUTH
DRAIN FIELD. WITH THE EXCEPTION OF BORING SSSB-2B, PCBS WERE DETECTED
IN THE BOTTOM SAMPLE OF EACH BORING (8 TO 20 FEET BELOW LAND SURFACE).
SAMPLE SSSB-4B (18-20) COLLECTED AT 18 TO 20 FEET BELOW LAND SURFACE HAD
A PCB CONCENTRATION OF 10 PPM (AROCLOR 1016). THIS WAS THE HIGHEST
CONCENTRATION DETECTED.
LESS THAN 1 PPM.
THE REMAINING SAMPLES HAD PCB CONCENTRATIONS
NO PCBS WERE DETECTED IN THE THREE SAMPLES COLLECTED IN BORING SSSB-5
LOCATED IN THE NORTH DRAIN FIELD. SAMPLE SSSB-7 (17-20) WAS THE ONLY
SAMPLE IN BORING SSSB-7 THAT HAD PCBS DETECTED. PCBS WERE ALSO DETECTED
IN THE ASSOCIATED METHOD BLANK SAMPLE (PREPARED BY THE LABORATORY) AT
0.25 PPM, THUS THIS CONCENTRATION MAY NOT BE REPRESENTATIVE OF THE
SAMPLE. PCBS WERE DETECTED IN ONLY ONE SAMPLE IN BORING SSSB-8, AT A
DEPTH OF 5-6 FEET. THIS WAS THE SHALLOWEST SAMPLE COLLECTED. PCBS WERE
DETECTED IN ALL THREE SAMPLES IN BORING SSSB-9B. PCB CONCENTRATIONS IN
THE NORTH DRAIN FIELD WERE ALL WELL BELOW 1 PPM, RANGING FROM NONE
DETECTED TO 0.377 PPM.
IN ADDITION TO PCBS, SAMPLE SSSB-4B (18-20), COLLECTED FROM THE SOUTH
DRAIN FIELD.AND SAMPLE SSSB-7 (17-20), COLLECTED FROM THE NORTH DRAIN
FIELD, WERE ANALYZED FOR THE HSL PARAMETERS. THE SEMI-VOLATILE COMPOUND
DI-N-BUTYL PHTHALATE WAS DETECTED IN BOTH SAMPLES, AND BIS (ETHYLHEXYL)
PHTHALATE WAS DETECTED IN SSSB-4B (18-20). NO PESTICIDE COMPOUNDS WERE
DETECTED. THE INORGANIC COMPOUNDS WERE ALL WITHIN THE RANGE OF
CONCENTRATIONS IN TABLES 5-30 AND 5-31.
WASTEWATER TREATMENT FACILITY
THE WASTEWATER TREATMENT FACILITY CONSISTED OF A PRIMARY SETTLING BASIN
AND A LARGE STABILIZATION LAGOON. THE TREATMENT SYSTEM WAS PRIMARILY
DESIGNED FOR NEUTRALIZATION OF ACID SOLUTIONS USED IN THE ETCHING AND
FORMING PROCESS AND FOR THE PRECIPITATION OF DISSOLVED MATERIALS SUCH AS
ALUMINUM. THE ALUMINUM PRECIPITATES SETTLED IN THE PRIMARY SETTLING
BASIN. THE FACILITY WAS MODIFIED BY REPLACING THE PRIMARY BASIN (NOW
REFERRED TO AS THE INACTIVE LAGOON) WITH A CONCRETE LINED EQUALIZATION
BASIN. THE INACTIVE LAGOON IS NO LONGER USED FOR WASTEWATER TREATMENT.
THE STABILIZATION BASIN IS STILL IN USE.
SIX SOIL BORINGS (SWSB-1 THROUGH 6) WERE INSTALLED IN THE INACTIVE
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LAGOON TO DETERMINE THE VERTICAL EXTENT OF SLUDGE. BORINGS WERE DRILLED
USING HOLLOW STEM AUGERS WITH SPLIT SPOON SOIL SAMPLES COLLECTED
CONTINUOUSLY. TOTAL DEPTH TO THE BOTTOM OF THE SLUDGE RANGED FROM
ELEVEN FEET BELOW LAND SURFACE AT BORING SWSB-1 TO THIRTEEN FEET BELOW
LAND SURFACE AT BORING SWSB-5. THE SURFACE AREA OF THE WASTE IS ABOUT
1,380 SQUARE YARDS. THE ESTIMATED TOTAL VOLUME OF SLUDGE IN THE
INACTIVE LAGOON IS 4,400 CUBIC YARDS.
SLUDGE FROM EACH BORING WAS COMPOSITED INTO ONE SAMPLE AND ANALYZED FOR
PCBS. ADDITIONALLY, SLUDGE FROM BORING SWSB-2 WAS ANALYZED FOR THE HSL
PARAMETERS. ANALYTICAL RESULTS ARE PRESENTED IN TABLE 5-80. THE
COMPOSITE SLUDGE SAMPLE HAD A TOTAL PCB CONCENTRATION OF 23,200 PPM AND
26,400 PPM (DUPLICATE SAMPLE). SAMPLE SWSB-2 (2-6) HAD A TOTAL PCB
CONCENTRATION OF 187 PPM.
THE VOLATILE ORGANIC COMPOUND TETRACHLOROETHENE WAS DETECTED IN THE
WASTE. NO SEMI-VOLATILE OR PESTICIDE COMPOUNDS WERE DETECTED. ALL OF
THE INORGANIC COMPOUNDS EXCEPT ALUMINUM AND ARSENIC WERE WELL WITHIN THE
RANGE OF CONCENTRATIONS IN TABLES 5-30 AND 5-31.
SUBSURFACE SOIL SAMPLES WERE COLLECTED FROM BELOW THE ALUMINUM HYDROXIDE
SLUDGE IN THE INACTIVE LAGOON. NINE SUBSURFACE SOIL SAMPLES WERE
COLLECTED. SAMPLE SWSB-5A (17-19) WAS ANALYZED FOR THE HSL PARAMETERS.
THE REMAINING SAMPLES WERE ANALYZED FOR PCBS ONLY. ANALYTICAL RESULTS
FOR PCBS ARE PRESENTED IN TABLE 5-81. HSL PARAMETERS DETECTED IN
SWSB-5A (17-19) ARE PRESENTED IN TABLE 5-82. PCBS WERE DETECTED IN ALL
NINE SAMPLES, RANGING FROM 23.2 PPM IN SWSB-1 (14-16) TO 34,300 PPM
DETECTED IN SWSB-6 (11.5-12). FIVE OF THESE SAMPLES EXCEEDED 50 PPM
TOTAL PCBS.
IN ADDITION TO PCBS, SAMPLE SWSB-5A (17-19) WAS ANALYZED FOR THE HSL
PARAMETERS. TOTAL XYLENE WAS DETECTED AT 0.06 PPM IN A DILUTED SAMPLE.
NO VOCS WERE DETECTED IN THE UNDILUTED SAMPLE. NO SEMI-VOLATILE OR
PESTICIDE COMPOUNDS WERE DETECTED. ALL OF THE INORGANIC COMPOUNDS
DETECTED WERE WITHIN THE RANGE OF CONCENTRATIONS IN TABLES 5-30 AND
5-31.
EPA SAMPLED SEDIMENTS IN THE STABILIZATION LAGOON ON MAY 10, 1989.
RESULTS OF THAT INVESTIGATION ARE SUMMARIZED IN TABLE 5-83.
GROUND WATER SAMPLES WERE OBTAINED FROM WELL SWMW-1. FIRST ROUND
SAMPLES WERE ANALYZED FOR PCBS, VOCS, PH, SPECIFIC CONDUCTANCE,
SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES, AND SULFATE. WELLS
SWMW-4 AND 6 WERE ALSO ANALYZED FOR ALL OF THE HSL PARAMETERS. BOTH
FILTERED AND NONFILTERED SAMPLES WERE COLLECTED FOR INORGANICS ANALYSIS.
TABLE 5-63 SUMMARIZES ANALYTICAL RESULTS FOR DETECTED PARAMETERS.
SECOND ROUND GROUND WATER SAMPLES WERE ANALYZED FOR VOCS, PCBS, PH,
SPECIFIC CONDUCTANCE, SUSPENDED SOLIDS, ALKALINITY, HARDNESS, CHLORIDES,
AND SULFATES.
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PCBS WERE DETECTED IN WELLS SWMW-2,3,4,5,6,7 AND 7A IN BOTH SAMPLING
ROUNDS WITH TOTAL PCB CONCENTRATIONS RANGING FROM 0.0032 PPM AT SWMW-3
(JANUARY 1989) TO 0.11 PPM IN WELL SWMW-5, ALSO IN JANUARY, 1989. PCBS
WERE DETECTED IN WELL SWMW-8 AND 9 ONLY IN THE SECOND ROUND OF SAMPLES
WITH TOTAL PCB CONCENTRATIONS OF 0.014 PPM AND 0.038 PPM, RESPECTIVELY.
PCBS WERE NOT DETECTED IN AREA E WELL SEMW-1 OR UPGRADIENT WELL SWMW-1
FOR THE WASTEWATER TREATMENT FACILITY.
SEVERAL VOLATILE ORGANIC COMPOUNDS (CHLOROFORM, 1,1-DICHLOROETHANE,
1,1,1-TRICHLOROETHANE, CARBON TETRACHLORIDE TRICHLOROETHENE, AND
TETRACHLOROETHENE) WERE DETECTED IN WELL SEMW-1 LOCATED IN AREA E,
UPGRADIENT OF THE WASTEWATER TREATMENT FACILITY. TOTAL VOCS (EXCLUDING
ACETONE) DETECTED IN SEMW-1 WERE 0.10 PPM (OCTOBER 1988) AND 0.107 PPM
(JANUARY 1989).
IN THE WASTEWATER TREATMENT FACILITY WELLS, TOTAL 1,2-DICHLOROETHENE,
TRICHLOROETHENE, AND TETRACHLOROETHENE WERE DETECTED IN WELLS SWMW-2
THROUGH SWMW-9 DURING BOTH SAMPLING EVENTS. IN ADDITION,
TRICHLOROETHENE AND TETRACHLOROETHENE WERE DETECTED IN BACKGROUND WELL
SWMW-1 DURING THE SECOND SAMPLING ROUND IN JANUARY 1989. THE
TRICHLOROETHENE CONCENTRATION DETECTED IN SWMW-1 WAS 0.007 PPM.
IN ADDITION TO TOTAL 1,2-DICHLOROETHENE, TRICHLOROETHANE AND
TETRACHLOROETHENE, SEVERAL OTHER VOCS (VINYL CHLORIDE,
1,1-DICHLOROETHENE, 1,1-DICHLOROETHANE, CHLOROFORM, 1,2-DICHLOROETHANE,
CARBON TETRACHLORIDE AND BENZENE) WERE DETECTED AT LESS FREQUENT
OCCURRENCES.
TOTAL VOC CONCENTRATIONS ARE INCLUDED IN TABLE 5-63. TOTAL VOC
CONCENTRATIONS RANGED FROM NONE DETECTED DURING THE FIRST SAMPLING ROUND
IN WELL SWMW-1 TO 3.306 PPM IN WELL SWMW-2 IN OCTOBER 1988.
TOTAL VOC CONCENTRATIONS IN WELL SWMW-9, LOCATED IMMEDIATELY UPGRADIENT
OF THE INACTIVE LAGOON, AND WELLS SWMW-2 AND 3, LOCATED IMMEDIATELY
DOWNGRADIENT OF THE INACTIVE LAGOON, RANGED FROM 0.608 PPM IN SWMW-3 TO
3.306 PPM IN SWMW-2. WELL SWMW-9 IS LOCATED APPROXIMATELY 45 FEET
UPGRADIENT OF THE INACTIVE LAGOON. THE PRESENCE OF VOCS MAY BE THE
RESULT OF DIRECT HYDROLOGIC CONNECTION (THROUGH FRACTURES) BETWEEN THE
INACTIVE LAGOON AND THE SCREENED PORTION OF WELL SWMW-9. WELL SWMW-4,
LOCATED DOWNGRADIENT OF THE INACTIVE LAGOON AND IMMEDIATELY UPGRADIENT
OF THE STABILIZATION LAGOON, HAD TOTAL VOC CONCENTRATIONS OF 1.101 PPM,
1.86 PPM AND 1.95 PPM (DUPLICATE SAMPLE). TOTAL VOCS IN WATER TABLE
WELLS SWMW-5,6,7 AND 8 RANGED FROM 0.095 PPM IN SWMW-8 TO 2.15 PPM IN
SWMW-5 AND SHOW DECREASES IN CONCENTRATION, WITH DISTANCE DOWNGRADIENT
FROM THE STABILIZATION LAGOON; HOWEVER, WELL SWMW-7A, SCREENED BELOW THE
WATER TABLE ON TOP OF BEDROCK, HAD HIGHER TOTAL VOC CONCENTRATIONS THAN
ADJACENT WATER TABLE WELL SWMW-7. DETECTED CONCENTRATIONS IN SWMW-7A
(1.96 PPM AND 2.57 PPM) WERE THE HIGHEST OF THE FIVE DOWNGRADIENT WELLS
FOR THE RESPECTIVE SAMPLING PERIODS.
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DURING THE FIRST ROUND SAMPLING IN OCTOBER 1988, WELLS SWMW-4 AND
SWMW-6 WERE ANALYZED FOR SEMI-VOLATILE AND PESTICIDE ORGANIC COMPOUNDS.
NO SEMI-VOLATILE COMPOUNDS WERE DETECTED. HEPTACHLOR EPOXIDE WAS THE
ONLY PESTICIDE ORGANIC COMPOUND DETECTED IN SWMW-4 (0.00021 PPM) AND
SWMW-6 (0.00066 PPM) DURING FIRST ROUND SAMPLING. THESE ARE EXTREMELY
LOW CONCENTRATIONS. SEMI-VOLATILE AND PESTICIDE ORGANICS COMPOUNDS WERE
NOT INCLUDED IN THE LIST OF ANALYTICAL PARAMETERS FOR SECOND ROUND
SAMPLES COLLECTED IN JANUARY 1989.
IN OCTOBER 1988, SAMPLES WERE OBTAINED FROM DOWNGRADIENT WELLS SWMW-4
AND 6 FOR INORGANIC COMPOUND ANALYSIS. TWELVE COMPOUNDS WERE DETECTED
IN THE SAMPLE FOR WELL SWMW-4. TEN INORGANIC COMPOUNDS WERE DETECTED IN
THE SAMPLE FOR SWMW-6. CONCENTRATIONS IN BOTH THE SAMPLES WERE LOW,
THEREFORE, METALS WERE NOT INCLUDED IN THE ANALYTICAL PARAMETERS FOR THE
SECOND ROUND GROUND WATER SAMPLES COLLECTED IN JANUARY 1989.
EPA WAS NOTIFIED OF THE ELIMINATION OF INORGANIC, SEMI-VOLATILE, AND
PESTICIDE ORGANIC COMPOUNDS FROM THE ANALYTICAL PARAMETER LIST FOR
SECOND ROUND SAMPLES IN A LETTER DATED JANUARY 10, 1989.
SEDIMENT SAMPLES WERE COLLECTED FROM DRAINAGE DITCHES AND SWALES NEAR
THE WASTEWATER TREATMENT FACILITY. THESE SAMPLES WERE COLLECTED FROM
NINE LOCATIONS (SWSD-3 THROUGH 11) ON JULY 13, 1988. SAMPLES WERE
ANALYZED FOR PCBS. ANALYTICAL RESULTS ARE PRESENTED IN TABLE 5-84.
SAMPLING SITES SWSD-3 THROUGH 7 ARE LOCATED IN A DRAINAGE DITCH
ORIGINATING-NEAR THE PLANT FACILITY AND EXTENDS SOUTHWARD ALONG THE EAST
SIDE OF THE INACTIVE LAGOON AND STABILIZATION LAGOON. SEDIMENT SAMPLING
POINTS SWSD-8 AND SWSD-9 ARE LOCATED IN A DRAINAGE SWALE DOWNGRADIENT OF
AREA 2 AND WERE SAMPLED TO DETERMINE IF PCBS HAVE MIGRATED FROM AREA B
TO THE WASTEWATER TREATMENT FACILITY. DRAINAGE IN THIS SWALE ALSO
DISCHARGES INTO THE OUTFALL DITCH TO THE STABILIZATION LAGOON. SAMPLES
SWSD-10 AND SWSD-11 WERE COLLECTED IN THE OUTFALL DITCH SOUTH OF SANGAMO
ROAD, DOWNGRADIENT OF THE WASTEWATER TREATMENT FACILITY.
PCBS WERE DETECTED IN NINE SEDIMENT SAMPLES. SAMPLING SITES SWSD-3, 4,
6 AND 8 ARE THE ONLY LOCATIONS WITH PCB CONCENTRATIONS GREATER THAN 50
PPM. SWSD-3, LOCATED UPGRADIENT FROM THE INACTIVE LAGOON, HAS A TOTAL
PCB CONCENTRATION OF 1680 PPM. SAMPLING LOCATION SWSD-4, LOCATED
ADJACENT TO THE EAST SIDE OF THE INACTIVE LAGOON, HAD A TOTAL PCB
CONCENTRATION OF 2,700 PPM. SEDIMENT SAMPLE SWSD-5, LOCATED
DOWNGRADIENT OF THE INACTIVE LAGOON, HAD A MUCH LOWER PCB CONCENTRATION
OF 22.2 PPM. SWSD-6 AND SWSD-7, LOCATED DOWNSTREAM OF THE INACTIVE
LAGOON AND ADJACENT TO THE ACTIVE LAGOON, HAS A TOTAL PCB CONCENTRATION
OF 124 PPM AND 6.5 PPM, RESPECTIVELY. A TOTAL PCB CONCENTRATION OF 319
PPM WAS DETECTED AT SWSD-8. TOTAL PCB CONCENTRATIONS DECREASED FURTHER
DOWNGRADIENT TO 19.7 PPM DETECTED IN SWSD-9.
TOTAL PCB CONCENTRATIONS OF 6.5 PPM AND 7.2 PPM (DUPLICATE SAMPLE) WERE
DETECTED IN SWSD-10. A TOTAL PCB CONCENTRATION OF 24.8 PPM WAS DETECTED
AT SAMPLING SITE SWSD-11.
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6.0 SUMMARY OF SITE RISKS
6.1 CONTAMINANTS OF CONCERN
A BASELINE RISK ASSESSMENT WAS CONDUCTED FOR THE PLANT SITE AND EACH OF
THE OFF-SITE AREAS. THE CONTAMINATED MEDIA OF CONCERN ARE GROUNDWATER,
SOIL AND SEDIMENT, SOLID WASTE AND SLUDGE. THE CONSTITUENTS OF CONCERN
FOR THE MEDIA OF CONCERN IN EACH LOCATION ARE GIVEN IN TABLE 6-1. TABLE
6-2 PROVIDES THE CONCENTRATION RANGES FOR THE CONTAMINANTS OF CONCERN.
THE MAJOR CONTAMINANT OF CONCERN AT THE SANGAMO SITE IS PCB. THE
SURFACE SOIL PCB EXPOSURE POINT CONCENTRATION FOR EACH SITE WAS BASED ON
THE MEAN OF THE DETECTED PCB CONCENTRATIONS FOR THE SURFACE SOIL SAMPLES
COLLECTED FOR THAT SITE. THE EXPOSURE POINT CONCENTRATIONS FOR OTHER
CARCINOGENIC SURFACE SOIL CONTAMINANTS OF CONCERN ON THE PLANT SITE WERE
ALSO BASED ON THE MEAN OF THE DETECTED SAMPLES. THE SURFACE SOIL
EXPOSURE POINT CONCENTRATIONS ARE CONTAINED IN TABLE 6-3. THE EXPOSURE
POINT CONCENTRATIONS FOR THE SOIL NONCARCINOGENIC CONTAMINANTS OF
CONCERN WERE BASED ON THE HIGHEST DETECTED CONCENTRATIONS. LEAD WAS
CONSIDERED TO BE A SOIL CONTAMINANT OF CONCERN AT THE WELBORN SITE. THE
LEAD EXPOSURE POINT CONCENTRATION WAS BASED ON AN AVERAGE SOIL LEAD
CONCENTRATION OF 31.4 MG/KG.
THE THREE CONTAMINANTS OF CONCERN AND THE EXPOSURE CONCENTRATIONS FOR
THE SPRING LOCATED SOUTH OF THE PLANT SITE ARE TETRACHLOROETHENE
(0.00084 MG/L), 1,2-DICHLOROETHENE (0.071 MG/L) AND TRICHLOROETHENE (0.2
MG/L). OTHER GROUNDWATER CONTAMINANTS WERE DETECTED IN THE PLUME
ASSOCIATED WITH THE PLANT SITE AND THE OFF SITE AREAS. THE RANGE OF
GROUNDWATER CONTAMINANT CONCENTRATIONS FOR THE SITE LOCATIONS IS
CONTAINED IN TABLE 6-2. ALTHOUGH THE CONSUMPTION OF GROUNDWATER WAS NOT
CONSIDERED TO BE A COMPLETE EXPOSURE PATHWAY IN THE PRP RISK ASSESSMENT,
REGION IV DOES NOT AGREE WITH THIS CONCLUSION. SECTIONS 6.2 AND 6.4
CONTAIN MORE DISCUSSION ON THE GROUNDWATER EXPOSURE PATHWAY.
6.2 EXPOSURE ASSESSMENT
POTENTIAL EXPOSURE PATHWAYS ARE DIRECT CONTACT WITH CONTAMINATED SOIL
AND SEDIMENTS, INHALATION OF CONTAMINATED AIR AND FUTURE CONSUMPTION OF
CONTAMINATED GROUNDWATER. AN ADDITIONAL INDIRECT EXPOSURE PATHWAY COULD
RESULT FROM LEACHING OF SURFACE AND SUBSURFACE CONTAMINANTS INTO THE
GROUNDWATER AND THE SUBSEQUENT CONSUMPTION OF GROUNDWATER.
DIRECT CONTACT WITH SURFACE SOIL AND SEDIMENTS IS CONSIDERED TO BE A
POTENTIALLY COMPLETE CURRENT EXPOSURE PATHWAY. DUE TO THE REMOTENESS OF
THE SITES, DIRECT CONTACT WAS ASSUMED TO OCCUR ON A ONCE-PER WEEK BASIS
AT MOST OF THE SITES. THE BREAZEALE SITE IS CONSIDERED A POTENTIAL
FUTURE BUILDING SITE, AND THE JOHN TROTTER SITE IS CURRENTLY OCCUPIED,
SO INTAKE LEVELS WERE BASED ON A DAILY EXPOSURE SCENARIO FOR THESE TWO
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SITES.
FOR NONCARCINOGENIC EFFECTS, THE DIRECT CONTACT EXPOSURE SCENARIO WAS
FOR CHILDREN CONSUMING 0.2 GRAMS OF SOIL PER DAY AND WEIGHING 17
KILOGRAMS. THE CARCINOGENIC DIRECT CONTACT DAILY INTAKE LEVEL WAS BASED
ON BOTH THE INGESTION AND DERMAL CONTACT PATHWAYS. THE INGESTION
PATHWAY ASSUMED A LIFETIME DAILY CONSUMPTION RATE OF 0.1 GRAMS OF SOIL
BY A 70 KILOGRAM ADULT. THE DERMAL PATHWAY ASSUMED A 540 MILLIGRAMS PER
EXPOSURE CONTACT RATE AND A 5 PERCENT ABSORPTION RATE OF PCBS THROUGH
THE SKIN.
VOLATILIZATION OF CONSTITUENTS IS NOT CONSIDERED TO BE A SIGNIFICANT
MIGRATION PATHWAY AT THE PLANT SITE OR AT THE OFF SITE AREAS. MEASURED
PCB AND VOC CONCENTRATIONS IN AIR WERE BELOW DETECTION LIMITS AT BOTH
THE PLANT AND OFF SITE AREAS. FOR THIS REASON, INHALATION WAS NOT
CONSIDERED TO BE A COMPLETE EXPOSURE PATHWAY. ONE EXCEPTION TO THIS WAS
THE DODGENS OFF SITE AREA. ALTHOUGH THE SITE IS GRASS COVERED AND IN
GENERAL FUGITIVE DUST GENERATION IS NOT A SIGNIFICANT EXPOSURE PATHWAY,
THE GRASS AT THE SITE IS MOWED WITH A TRACTOR MOWER SEVERAL TIMES A YEAR
DURING THE SUMMER MONTHS. THE TRACTOR OPERATOR COULD BE POTENTIALLY
EXPOSED TO PCB CONTAINING DUST GENERATED BY THE MOWER. THE EXPOSURE
FREQUENCY FOR THIS SCENARIO IS 10 DAYS A YEAR FOR 2 HOURS A DAY. THE
BREATHING RATE WAS ASSUMED TO BE 1.3 M3/HOUR, 10 PERCENT FOR THE
PERCENTAGE OF INHALED DUST INGESTED AND 30 PERCENT FOR THE PERCENTAGE OF
PCBS ABSORBED FROM THE INGESTED DUST.
THE CONSUMPTION OF CONTAMINATED GROUNDWATER WAS NOT CONSIDERED TO BE A
COMPLETE EXPOSURE PATHWAY IN THE RISK ASSESSMENT BECAUSE NO DOWNGRADIENT
GROUNDWATER USERS HAVE BEEN IDENTIFIED AND TREATED WATER IS AVAILABLE TO
ALL RESIDENCES DOWNGRADIENT OF THE PLANT SITE. HOWEVER, THE ON-SITE
AQUIFER IS CLASSIFIED AS IIA AND THE AQUIFER IN THE OFF SITE AREAS IS
CLASSIFIED AS 118, IMPLYING THAT THE ON-SITE AQUIFER IS CONSIDERED TO BE
A CURRENT DRINKING WATER SOURCE AND THE OFF SITE AQUIFER IS A POTENTIAL
SOURCE OF DRINKING WATER. THE CLASS II STATUS OF THE AQUIFER IN THE
VICINITY OF THE SITE INDICATES THAT A FUTURE SCENARIO FOR THE
CONSUMPTION OF GROUNDWATER SHOULD HAVE BEEN ADDRESSED IN THE RISK
ASSESSMENT. HOWEVER, SINCE THIS WAS NOT DONE, THE NEED FOR GROUNDWATER
REMEDIATION WILL BE ADDRESSED IN THE RISK CHARACTERIZATION SECTION OF
THIS SUMMARY BY COMPARING GROUNDWATER CONCENTRATIONS FOR THE
CONTAMINANTS OF CONCERN WITH THE APPROPRIATE MCLS OR MCLGS. HEALTH
BASED NUMBERS ARE PROVIDED IN THE ABSENCE OF GROUNDWATER STANDARDS.
THE AREAS OF SOLID WASTE AND SLUDGE DISPOSAL WERE SAMPLED BOTH ON THE
SURFACE AND BY SUBSURFACE BORINGS. THE SURFACE SAMPLES WERE
INCORPORATED WITH THE OTHER SURFACE SOIL SAMPLES TO DETERMINE SURFACE
SOIL EXPOSURE POINT CONCENTRATIONS. THE SUBSURFACE CONTAMINANTS POSE AN
INDIRECT EXPOSURE PATHWAY THROUGH LEACHING TO GROUNDWATER AND THE
SUBSEQUENT CONSUMPTION OF CONTAMINATED GROUNDWATER. THESE AREAS WILL BE
REMEDIATED BASED ON SOIL CLEANUP CONCENTRATIONS FOR THE PROTECTION OF
GROUNDWATER.
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6.3 TOXICITY ASSESSMENT
CANCER POTENCY FACTORS (CPFS) HAVE BEEN DEVELOPED BY EPA'S CARCINOGENIC
ASSESSMENT GROUP FOR ESTIMATING EXCESS LIFETIME CANCER RISKS ASSOCIATED
WITH EXPOSURE TO POTENTIALLY CARCINOGENIC CHEMICALS. CPFS, WHICH ARE
EXPRESSED IN UNITS OF (MG/KG-DAY)1, ARE MULTIPLIED BY THE ESTIMATED
INTAKE OF A POTENTIAL CARCINOGEN, IN MG/KG-DAY, TO PROVIDE AN
UPPER-BOUND ESTIMATE OF THE EXCESS LIFETIME CANCER RISK ASSOCIATED WITH
EXPOSURE AT THAT INTAKE LEVEL. THE TERM "UPPER BOUND" REFLECTS THE
CONSERVATIVE ESTIMATE OF THE RISK CALCULATED FROM THE CPF. USE OF THIS
APPROACH MAKES UNDERESTIMATION OF THE ACTUAL CANCER RISK HIGHLY
UNLIKELY. CANCER POTENCY FACTORS ARE DERIVED FROM THE RESULTS OF HUMAN
EPIDEMIOLOGICAL STUDIES OR CHRONIC ANIMAL BIOASSAYS TO WHICH
ANIMAL-TO-HUMAN EXTRAPOLATION AND UNCERTAINTY FACTORS HAVE BEEN APPLIED.
THE CPFS FOR THE SITE CONTAMINANTS OF CONCERN ARE CONTAINED IN TABLE
6-4.
REFERENCE DOSES (RFDS) HAVE BEEN DEVELOPED BY EPA FOR INDICATING THE
POTENTIAL FOR ADVERSE HEALTH EFFECTS FROM EXPOSURE TO CHEMICALS
EXHIBITING NONCARCINOGENIC EFFECTS. RFDS, WHICH ARE EXPRESSED IN UNITS
OF MG/KG-DAY, ARE ESTIMATES OF LIFETIME DAILY EXPOSURE LEVELS FOR
HUMANS,INCLUDING SENSITIVE INDIVIDUALS. ESTIMATED INTAKES OF CHEMICALS
FROM ENVIRONMENTAL MEDIA (E.G.1 THE AMOUNT OF A CHEMICAL INGESTED FROM
CONTAMINATED DRINKING WATER) CAN BE COMPARED TO THE RFD. RFDS ARE
DERIVED FROM HUMAN EPIDEMIOLOGICAL STUDIES OR ANIMAL STUDIES TO WHICH
UNCERTAINTY FACTORS HAVE BEEN APPLIED (E.G., TO ACCOUNT FOR THE USE OF
ANIMAL DATA TO PREDICT EFFECTS ON HUMANS). THESE UNCERTAINTY FACTORS
HELP ENSURE THAT THE RFDS WILL NOT UNDERESTIMATE THE POTENTIAL FOR
ADVERSE NONCARCINOGENIC EFFECTS TO OCCUR. THE RFDS FOR THE SITE
CONTAMINANTS OF CONCERN ARE CONTAINED IN TABLE 6-4.
6.4 RISK CHARACTERIZATION
EXCESS LIFETIME CANCER RISKS ARE DETERMINED BY MULTIPLYING THE INTAKE
LEVEL WITH THE CANCER POTENCY FACTOR. THESE RISKS ARE PROBABILITIES-HAT
ARE GENERALLY EXPRESSED IN SCIENTIFIC NOTATION (E.G.,1 X (10-6) OR
1E-6). AN EXCESS LIFETIME CANCER RISK OF 1 X (10-6) INDICATES THAT, AS
A PLAUSIBLE UPPER BOUND, AN INDIVIDUAL HAS A ONE IN A MILLION CHANCE OF
DEVELOPING CANCER AS A RESULT OF SITE-RELATED EXPOSURE TO A CARCINOGEN
OVER A 70-YEAR LIFETIME UNDER THE SPECIFIC EXPOSURE CONDITIONS AT A
SITE. THE AGENCY CONSIDERS INDIVIDUAL EXCESS CANCER RISK IN THE RANGE
OF (10-4) TO (10-6) AS PROTECTIVE; HOWEVER THE (10-6) RISK LEVEL IS
GENERALLY USED AS THE POINT OF DEPARTURE FOR SETTING CLEANUP LEVELS OF
SUPERFUND SITES.
POTENTIAL CONCERN FOR NONCARCINOGENIC EFFECTS OF A SINGLE CONTAMINANT IN
A SINGLE MEDIUM IS EXPRESSED AS THE HAZARD QUOTIENT (HQ) (OR THE RATIO
OF THE ESTIMATED INTAKE DERIVED FROM THE CONTAMINANT CONCENTRATION IN A
GIVEN MEDIUM TO THE CONTAMINANT'S REFERENCE DOSE). BY ADDING THE HQS
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FOR ALL CONTAMINANTS WITHIN A MEDIUM OR ACROSS ALL MEDIA TO WHICH A
GIVEN POPULATION MAY REASONABLY BE EXPOSED, THE HAZARD INDEX (HI) CAN BE
GENERATED. THE HI PROVIDES A USEFUL REFERENCE POINT FOR GAUGING THE
POTENTIAL SIGNIFICANCE OF MULTIPLE CONTAMINANT EXPOSURES WITHIN A SINGLE
MEDIUM OR ACROSS MEDIA.
THE GREATEST CURRENT SITE RISKS ARE ATTRIBUTABLE TO DIRECT CONTACT WITH
PCBS IN THE SURFACE SOIL. THESE RISK LEVELS RANGE FROM 1.2 X (10-5) FOR
THE BREAZEALE SITE TO 1.3 X (10-3) FOR AREA B OF THE PLANT SITE. THE
CANCER RISK LEVELS ASSOCIATED WITH EXPOSURE TO PCBS IN SURFACE OIL ARE
SUMMARIZED ON TABLE 6-5. THE PREDICTED RISK LEVELS FOR EXPOSURE TO
SURFACE SOIL VOCS AT AREA B ARE LOW AND DO NOT MAKE A SIGNIFICANT
CONTRIBUTION TO THE RISKS ASSOCIATED WITH EXPOSURE TO PCBS. THE HAZARD
INDEX FOR DIRECT CONTACT WITH NONCARCINOGENS IN THE SURFACE SOIL AT THE
PLANT SITE ARE BELOW UNITY (1.9 X (10-4)).
THE BASELINE RISK ASSOCIATED WITH GRASS MOWING FOR THE DODGENS SITE IS
8.2 X (10-8).
LEAD WAS DETECTED IN THE SOIL AT CONCENTRATIONS EXCEEDING BACKGROUND AT
THE WELBORN SITE. HOWEVER, THE AVERAGE CONCENTRATION (31.4 MG/KG) IS
WELL BELOW THE OSWER INTERIM DIRECTIVE (# 9355.4-02) RECOMMENDED RANGE
(500 - 1000 MG/KG). IN ADDITION, THIS CONCENTRATION IS ALSO WELL BELOW
THE SOIL LEAD CLEANUP CONCENTRATION THAT WOULD BE GENERATED BY USING
EXPOSURE DEFAULT VALUES WITH THE EPA BAD UPTAKE/BIOKINETIC MODEL.
A BASELINE RISK WAS CALCULATED FOR THE DAILY CONSUMPTION OF WATER FROM A
SPRING LOCATED DOWNGRADIENT FROM THE SITE. THE NONCARCINOGENIC RISK, OR
HAZARD INDEX, WAS CALCULATED AT 0.11. THE CARCINOGENIC RISK WAS
DETERMINED TO BE 7.5 X (10-5). ALTHOUGH THE RISK ASSOCIATED WITH THE
FUTURE CONSUMPTION OF CONTAMINATED GROUNDWATER WAS NOT CALCULATED, THE
APPROPRIATE GROUNDWATER STANDARDS AND HEALTH BASED NUMBERS ARE CONTAINED
IN TABLE 6-6. A COMPARISON OF GROUNDWATER CONCENTRATIONS WITH THE
NUMBERS IN THIS TABLE WILL ALLOW A DETERMINATION TO BE MADE CONCERNING
WHICH GROUNDWATER CONTAMINANTS WILL REQUIRE REMEDIATION.
6.5 ENVIRONMENTAL RISKS
THE ENVIRONMENTAL RECEPTORS AT THE SANGAMO PLANT SITE AND OFF SITE AREAS
WOULD PRIMARILY BE AFFECTED THROUGH SOIL AND SURFACE WATER SEDIMENT
PATHWAYS. NO ENDANGERED SPECIES OR CRITICAL HABITATS ARE KNOWN TO OCCUR
IN THE VICINITY OF THE SITE.
THE CONSTITUENTS IN THE SURFACE SOIL COULD IMPACT TERRESTRIAL ANIMALS.
BURROWING ANIMALS, SUCH AS RODENTS, REPTILES, AND INSECTS MIGHT BE
AFFECTED BY CONTAMINANTS IN THE BURIED WASTES.
THE SURFACE WATER DITCHES AT THE PLANT SITE AND THE DITCHES AND CREEKS
ADJACENT TO THE OFF SITE AREAS ARE LOW IN VOLUME AND ARE NOT KNOWN TO
CONTAIN EDIBLE FISH.
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#DA
7.0 DESCRIPTION OF ALTERNATIVE 1: NO ACTION
7.1.1 DESCRIPTION
THE NO ACTION ALTERNATIVE IS RETAINED AS THE BASELINE CASE FOR RISK
COMPARISON. NO REMEDIAL ACTIONS WOULD BE PERFORMED ON ANY OF THE MEDIA
OF CONCERN (GROUNDWATER, SOIL, SLUDGE, AND SOLID WASTES) AT EITHER THE
PLANT SITE OR THE OFF-SITE AREAS. WASTE DISPOSAL AREAS DEFINED DURING
THE RI WOULD REMAIN IN THEIR PRESENT CONDITION. THE ONLY ACTIVE
COMPONENT OF THIS ALTERNATIVE IS LONG-TERM GROUNDWATER AND SURFACE SOIL
MONITORING. THIS PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE EFFECT OF
WASTE CONSTITUENTS ON THE SITE OVER A 30-YEAR DESIGN LIFE.
GROUNDWATER QUALITY WOULD BE MONITORED SEMI-ANNUALLY BY SAMPLING AND
ANALYSIS FOR VOLATILES, SEMI-VOLATILES, METALS, AND PCBS. ANNUALLY,
SAMPLES WOULD BE COLLECTED AND ANALYZED FOR THE VOLATILE, SEMI-VOLATILE
FRACTION OF THE TARGET COMPOUND LIST (TCL). DIOXINS AND FURANS WOULD
ALSO BE ANALYZED ANNUALLY AT THE PLANT SITE. IF NEW COMPOUNDS ARE
DETECTED, THEY WILL BE ADDED TO THE SEMI-ANNUAL MONITORING PROGRAM.
HOWEVER, SINCE MANY OF THE GROUNDWATER MONITORING WELLS ARE LOCATED IN
FRACTURED BEDROCK, THE WATER QUALITY DETERMINED BY ANALYSES OF SAMPLES
FROM THESE FRACTURES MAY NOT INDICATE GROUNDWATER QUALITY IN OTHER
UNCONNECTED FRACTURE SYSTEMS. THE GROUNDWATER QUALITY WOULD CHANGE AS
NATURAL ATTENUATION DEGRADED THE WASTE CONSTITUENTS PRESENT IN THE
WATER.
SURFACE SOIL MONITORING WOULD BE PERFORMED ANNUALLY TO EVALUATE
MIGRATION OF PCBS. SAMPLES WOULD BE COLLECTED FROM EACH WASTE DISPOSAL
LOCATION AT PLANT AND OFF-SITE AREAS. AS WITH THE GROUNDWATER
MONITORING, A 30 YEAR PERIOD HAS BEEN USED AS A BASIS FOR COST
ESTIMATION.
SANGAMO PLANT SITE
THIS PROGRAM WOULD INCLUDE EXISTING ON-SITE MONITORING WELLS AND
OFF-SITE WELL. EPA HAS CLASSIFIED GROUNDWATER AS CLASS IIA ON THE PLANT
PROPERTY. A 30-YEAR PERIOD HAS BEEN USED AS A BASIS FOR COST
ESTIMATION. THE MONITORING PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELLS: MONITORING OF THE FOLLOWING UPGRADIENT WELLS IS
PROPOSED. WELLS SAMW-1, SBMW-1, AND SWMW-1 ARE LOCATED NEAR AREAS A, B,
AND THE WASTEWATER TREATMENT FACILITY. AREAS C, D, E F, G, AND H ARE ON
TOP OF A RIDGE AND NO UPGRADIENT WELLS ARE TOPOGRAPHICALLY POSSIBLE.
BACKGROUND WELLS WILL SERVE AS POINTS OF COMPARISON FOR WATER QUALITY
MONITORING RESULTS FROM THE WASTE DISPOSAL AREAS.
ON-SITE MONITORING WELLS: EXISTING WELLS SAMW-2 AND 3, SBMW-2 AND 3,
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SDMW-1, 2, 3, AND 4, SCMW-5, SFMW-6, SGMW-7, 8, AND 9, SHMW-10, SEMW-1,
SWMW-2, 3, 4, 5, 6, 7, 7A, 8, AND 9 ARE PROPOSED FOR LONG-TERM
MONITORING. THESE WELLS ARE DOWNGRADIENT OF WASTE DISPOSAL AREAS.
OFF-PROPERTY MONITORING WELLS: SEVERAL WELLS (SPMW 1, 1A, 1B, 2, 3, 3A,
3B, 4, 5, AND 6) ARE PROPOSED FOR LONG-TERM DETECTION MONITORING.
MONITORING WELLS SPMW-1, 1A, AND 1B WILL COMPRISE A NEST LOCATED SOUTH
OF THE SITE ON THE SOUTH SIDE OF TOWN CREEK. WELL SPMW-2 WILL BE A
BEDROCK WELL LOCATED BETWEEN AREAS C, D, F, G, AND H AND THE NIX SPRING.
THE REMAINING WELLS WILL BE LOCATED NORTH OF THE SITE. MONITORING WELLS
SPMW-3, 3A, AND 3B, WILL COMPRISE A MONITORING WELL NEST ON THE NORTH
SIDE OF THE UNNAMED TRIBUTARY TO TWELVEMILE CREEK. WELLS SPMW-4, 5, AND
6 ARE BEDROCK WELLS AND WILL BE LOCATED IN DRAINAGE SWALES DOWNGRADIENT
OF SITES C, D, F, G, AND H. WELL NESTS WILL CONSIST OF SHALLOW AND DEEP
WELLS FOR MONITORING GROUNDWATER IN THE SAPROLITE AND ONE WELL TO
MONITOR GROUNDWATER IN BEDROCK.
THE SELECTION OF MONITORING WELLS FOR LONG-TERM MONITORING OF VARIOUS
WASTE DISPOSAL AREAS IS BASED ON LOCATION. WELLS ARE GENERALLY LOCATED
DOWNGRADIENT OF THE WASTE DISPOSAL AREAS. EACH CAN BE USED TO MONITOR
CONSTITUENT CONCENTRATIONS DOWNGRADIENT OF THE WASTE DISPOSAL AREAS.
FOR THE NO ACTION ALTERNATIVE, SAMPLES WOULD BE COLLECTED SEMIANNUALLY
AND ANALYZED FOR PCBS, TRICHLOROETHENE, TETRACHLOROETHENE, TOTAL
1,2-DICHLOROETHENE, 1,1,1-TRICHLOROETHANE, 1,1-DICHLOROETHENE,
1,1-DICHLOROETHANE, CHLOROFORM, BENZENE, AND 1,2,-DICHLOROETHANE. AS
PART OF THE MONITORING PROGRAM, WATER LEVELS WOULD BE MEASURED TO ASSESS
THE GROUNDWATER FLOW DIRECTION. THE MONITORING AND WELL MAINTENANCE
PERIOD IS ASSUMED TO BE 30 YEARS.
EPA HAS CLASSIFIED GROUNDWATER AS CLASS IIB AT THE OFF-SITE AREAS.
BREAZEALE SITE
A GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE
EFFECT OF WASTE CONSTITUENTS AT THE BREAZEALE SITE ON GROUNDWATER OVER A
30-YEAR DESIGN LIFE. THIS PROGRAM WOULD INCLUDE EXISTING ON-SITE
MONITORING WELLS. A 30-YEAR PERIOD HAS BEEN USED FOR COST ESTIMATION.
THE MONITORING PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELL: MONITORING OF UPGRADIENT WELL BRMW-1 IS PROPOSED. THIS
WELL IS LOCATED TO THE NORTHWEST OF THE SITE AND WOULD SERVE AS A POINT
OF COMPARISON FOR WATER QUALITY MONITORING RESULTS FROM THE SITE.
ON-SITE MONITORING WELLS: EXISTING WELLS BRMW-2, 2A, 3, 3A, 3B, 4, 4A,
5, 5A, 5B, 8, 8A, 10, 11, 12, 12A, 14, AND 14A ARE PROPOSED FOR LONGTERM MONITORING. THESE WELLS ARE LOCATED DOWNGRADIENT OF THE AREA OF
WASTE DEPOSITION.
ON-SITE DETECTION MONITORINA WELLS: WELLS BRMW-7, 9, AND 13 ARE PROPOSED
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FOR LONG-TERM DETECTION MONITORING. THESE WELLS ARE LOCATED TO THE
EAST, WEST, AND SOUTH OF THE VOC PLUME.
WELLS SELECTED FOR LONG-TERM MONITORING OF THE BREAZEALE SITE ARE
GENERALLY LOCATED DOWNGRADIENT OF THE AREA OF WASTE DEPOSITION. THE
SAMPLING PROGRAM FOR THE NO ACTION ALTERNATIVE WOULD BE PERFORMED ON A
SEMI-ANNUAL BASIS AND THE RESULTS WOULD BE SUBMITTED IN SEMI-ANNUAL
REPORTS. CHEMICAL ANALYSES ARE PROPOSED FOR PCBS, TRICHLOROETHENE,
TETRACHLOROETHENE, BENZENE, TOLUENE, TOTAL 1,2-DICHLOROETHENE,
1,1,2,2-TETRACHLOROETHANE, BIS (2-ETHYLHEXYL) PHTHALATE, AND
1,1,1,-TRICHLOROETHANE. AS PART OF THE MONITORING PROGRAM, WATER LEVELS
IN MONITORING WELLS WOULD BE MEASURED TO ASSESS THE GROUNDWATER FLOW
DIRECTION. FOR COST ESTIMATING, THE WELL MONITORING AND MAINTENANCE
PERIOD IS ASSUMED TO BE 30 YEARS.
NIX SITE
A GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE
EFFECT OF WASTE CONSTITUENTS AT THE NIX SITE ON GROUNDWATER OVER A
30-YEAR DESIGN LIFE. THIS PROGRAM WOULD INCLUDE EXISTING ON-SITE
MONITORING WELLS. A 30-YEAR PERIOD HAS BEEN USED FOR COST ESTIMATION.
THE MONITORING PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELL: MONITORING OF UPGRADIENT WELL NXMW-1 IS PROPOSED. THIS
WELL IS LOCATED TO THE NORTHEAST OF THE SITE AND WOULD SERVE AS A POINT
OF COMPARISON FOR WATER QUALITY MONITORING RESULTS FROM THE SITE.
ON-SITE DETECTION MONITORING WELLS: WELLS NXMW 2, 3, AND 4 ARE PROPOSED
FOR LONG-TERM DETECTION MONITORING. THESE WELLS ARE LOCATED TO THE
NORTH, SOUTHEAST, AND WEST OF THE AREA OF WASTE DEPOSITION,
RESPECTIVELY.
THE SAMPLING PROGRAM FOR THE NO ACTION ALTERNATIVE WOULD BE PERFORMED ON
A SEMI-ANNUAL BASIS AND THE RESULTS WOULD BE SUBMITTED IN A SEMI-ANNUAL
REPORTS. CHEMICAL ANALYSES ARE PROPOSED FOR PCBS. AS PART OF THE
MONITORING PROGRAM, WATER LEVELS IN MONITORING WELLS WOULD BE MEASURED
TO ASSESS THE GROUNDWATER FLOW DIRECTION. FOR COST ESTIMATING, THE WELL
MONITORING AND MAINTENANCE PERIOD IS ASSUMED TO BE 30 YEARS.
DODGENS SITE
A GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE
EFFECT OF WASTE CONSTITUENTS AT THE DODGENS SITE ON GROUNDWATER OVER A
30-YEAR DESIGN LIFE. THIS PROGRAM WOULD INCLUDE EXISTING ON-SITE
MONITORING WELLS. A 30 YEAR PERIOD HAS BEEN USED FOR COST ESTIMATION.
THE MONITORING PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELL: MONITORING OF UPGRADIENT WELL DGMW-1 IS PROPOSED. THIS
WELL IS LOCATED TO THE WEST OF THE SITE AND WOULD SERVE AS A POINT OF
COMPARISON FOR WATER QUALITY MONITORING RESULTS FROM THE SITE.
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ON-SITE MONITORING WELLS: EXISTING WELLS DGMW-2, 3, AND 4 ARE PROPOSED
FOR LONG-TERM MONITORING. THESE WELLS ARE LOCATED DOWNGRADIENT OF THE
AREA OF WASTE DEPOSITION.
ON-SITE DETECTION MONITORING WELLS: WELL DGMW-3A IS PROPOSED FOR
LONG-TERM DETECTION MONITORING. THIS WELL IS LOCATED TO THE EAST OF THE
AREA OF WASTE DEPOSITION NEAR MIDDLE PORK TWELVEMILE CREEK.
WELLS SELECTED FOR LONG-TERM MONITORING OF THE DODGENS SITE ARE LOCATED
DOWNGRADIENT OF THE AREA OF WASTE DEPOSITION. THE SAMPLING PROGRAM FOR
THE NO ACTION ALTERNATIVE WOULD BE PERFORMED ON A SEMI-ANNUAL BASIS AND
THE RESULTS WOULD BE SUBMITTED IN SEMI-ANNUAL REPORTS. CHEMICAL
ANALYSES ARE PROPOSED FOR PCBS, TRICHLOROETHENE, TETRACHLOROETHENE, BIS
(2-ETHYLHEXYL) PHTHALATE, CADMIUM, COPPER, LEAD, AND SILVER. AS PART OF
THE MONITORING PROGRAM, WATER LEVELS IN MONITORING WELLS WOULD BE
MEASURED TO ASSESS THE GROUNDWATER FLOW DIRECTION. FOR COST ESTIMATING,
THE WELL MONITORING AND MAINTENANCE PERIOD IS ASSUMED TO BE 30 YEARS.
CROSS ROADS SITE
A GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE
IMPACT OF THE CROSS ROADS SITE ON GROUNDWATER OVER A 30-YEAR DESIGN
LIFE THIS PROGRAM WOULD INCLUDE EXISTING AND PROPOSED MONITORING WELLS.
A 30-YEAR PERIOD HAS BEEN USED FOR COST ESTIMATION. THE MONITORING
PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELL: MONITORING OF UPGRADIENT WELL CRMW-1 IS PROPOSED.
WELL IS LOCATED NORTH OF THE SITE AND WILL SERVE AS A POINT OF
COMPARISON FOR WATER QUALITY MONITORING RESULTS FROM THE SITE.
THIS
ON-SITE MONITORING WELLS: EXISTING WELLS CRMW-2, 3, AND 3A ARE PROPOSED
FOR LONG-TERM MONITORING. THESE WELLS ARE LOCATED DOWNGRADIENT OF THE
AREA OF WASTE DEPOSITION.
ON-SITE DETECTION MONITORING WELLS: WELL NEST CRMW-4, 4A, AND CRMW-5, 5A
ARE PROPOSED FOR LONG-TERM DETECTION MONITORING. THESE WELLS ARE
LOCATED SOUTHEAST AND EAST OF THE AREA OF WASTE DEPOSITION,
RESPECTIVELY.
THE SAMPLING PROGRAM FOR THE NO ACTION ALTERNATIVE WOULD BE PERFORMED ON
A SEMI-ANNUAL BASIS AND THE RESULTS WOULD BE SUBMITTED IN SEMI-ANNUAL
REPORTS. CHEMICAL ANALYSES ARE PROPOSED FOR PCBS, TRICHLOROETHENE,
TETRACHLOROETHENE, TOTAL 1,2-DICHLOROETHENE, SILVER, CADMIUM, AND
CYANIDE. AS PART OF THE MONITORING PROGRAM, WATER LEVELS IN MONITORING
WELLS WOULD BE MEASURED TO ASSESS THE GROUNDWATER FLOW DIRECTION. FOR
COST ESTIMATING, THE MONITORING AND WELL MAINTENANCE PERIOD IS ASSUMED
TO BE 30 YEARS.
JOHN TROTTER SITE
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A GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE
IMPACT OF WASTE CONSTITUENTS AT THE JOHN TROTTER SITE ON GROUNDWATER
OVER A 30-YEAR PERIOD. THIS PROGRAM WOULD INCLUDE EXISTING ON-SITE
MONITORING WELLS. A 30-YEAR PERIOD HAS BEEN USED FOR COST ESTIMATION.
THE MONITORING PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELL: MONITORING OF UPGRADIENT WELL JTMW-1 IS PROPOSED.
WELL IS LOCATED NORTH OF THE SITE AND WOULD SERVE AS A POINT OF
COMPARISON FOR WATER QUALITY MONITORING RESULTS FROM THE SITE.
THIS
ON-SITE DETECTION MONITORING WELLS: JTMW-2, 3, 3A, AND 4 ARE PROPOSED
FOR LONG-TERM DETECTION MONITORING. THESE WELLS ARE LOCATED SOUTH OF
THE AREA OF WASTE DEPOSITION.
WELLS SELECTED FOR LONG-TERM GROUNDWATER MONITORING AT THE JOHN TROTTER
SITE ARE LOCATED DOWNGRADIENT OF THE AREA OF WASTE DEPOSITION. THE
SAMPLING PROGRAM FOR THE NO ACTION ALTERNATIVE WOULD BE PERFORMED ON A
SEMIANNUAL BASIS AND THE RESULTS WOULD BE SUBMITTED IN SEMI-ANNUAL
REPORTS. CHEMICAL ANALYSES ARE PROPOSED FOR PCBS, TRICHLOROETHENE,
TETRACHLOROETHENE, ANTIMONY, CADMIUM, COPPER, LEAD, AND SILVER. AS PART
OF THE MONITORING PROGRAM, WATER LEVELS IN MONITORING WELLS WOULD BE
MEASURED TO ASSESS THE GROUNDWATER FLOW DIRECTION. FOR COST ESTIMATING,
THE WELL MONITORING AND MAINTENANCE PERIOD IS ASSUMED TO BE 30 YEARS.
WELBORN SITE
A GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED TO ASSESS THE
EFFECT OF WASTE CONSTITUENTS AT THE WELBORN SITE ON GROUNDWATER OVER A
30-YEAR DESIGN LIFE. THIS PROGRAM WOULD INCLUDE EXISTING ON-SITE
MONITORING WELLS. A 30-YEAR PERIOD HAS BEEN USED FOR COST ESTIMATION.
THE MONITORING PROGRAM HAS THE FOLLOWING ELEMENTS:
BACKGROUND WELL: MONITORING OF UPGRADIENT WELL WBMW-1 IS PROPOSED. THIS
WELLS IS LOCATED TO THE NORTHEAST OF THE SITE AND WOULD SERVE AS A POINT
OF COMPARISON FOR WATER QUALITY MONITORING RESULTS FROM THE SITE.
ON-SITE DETECTION MONITORING WELLS: WELLS WBMW 2, 3, AND 4 ARE PROPOSED
FOR LONG-TERM DETECTION MONITORING. THESE WELLS ARE LOCATED TO THE EAST
AND SOUTH OF THE AREAS OF WASTE DEPOSITION.
WELLS SELECTED FOR LONG-TERM MONITORING OF THE WELBORN SITE ARE
GENERALLY LOCATED DOWNGRADIENT OF THE AREA OF WASTE DEPOSITION. THE
SAMPLING PROGRAM FOR THE NO ACTION ALTERNATIVE WOULD BE PERFORMED ON A
SEMI-ANNUAL BASIS AND THE RESULTS WOULD BE SUBMITTED IN SEMI-ANNUAL
REPORTS. CHEMICAL ANALYSES ARE PROPOSED FOR PCBS AND LEAD. AS PART OF
THE MONITORING PROGRAM, WATER LEVELS IN MONITORING WELLS WOULD BE
MEASURED TO ASSESS THE GROUNDWATER FLOW DIRECTION. FOR COST ESTIMATING,
THE WELL MONITORING AND MAINTENANCE PERIOD IS ASSUMED TO BE 30 YEARS.
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7.1.2 EFFECTIVENESS
THE NO-ACTION ALTERNATIVE WOULD NOT REDUCE THE TOXICITY MOBILITY OR
VOLUME OF CONTAMINATED MEDIA AT THE SITE. SINCE MONITORING IS THE ONLY
COMPONENT OF THIS ALTERNATIVE, THERE WOULD BE NO INCREASE IN
PROTECTIVENESS TO HUMAN HEALTH OR THE ENVIRONMENT.
7.2 ALTERNATIVE 2: LIMITED ACTION
7.2.1 DESCRIPTION
THE LIMITED ACTION ALTERNATIVE ESTABLISHES INSTITUTIONAL MEASURES TO
LIMIT EXPOSURE PATHWAYS IN THE FOUR AFFECTED MEDIA: GROUNDWATER, SOIL,
SLUDGE, AND SOLID WASTES. THESE INSTITUTIONAL MEASURES INCLUDE THE
FOLLOWING:
*
RESTRICTIONS ON GROUNDWATER USE,
*
FENCING TO LIMIT ACCESS TO AFFECTED SOLID MATERIALS, AND
*
DEED RESTRICTIONS TO CONTROL FUTURE LAND USE.
GROUNDWATER
AS PROPOSED IN THIS ALTERNATIVE, LIMITED ACTION ON GROUNDWATER WOULD BE
USED ONLY FOR THE PLANT, CROSS ROADS, BREAZEALE, AND DODGENS SITES.
LIMITED ACTION AT THESE LOCATIONS WOULD CONSIST OF GROUNDWATER ACCESS
RESTRICTIONS, PROVISIONS FOR ONE CONNECTION TO PUBLIC WATER SUPPLY, AND
GROUNDWATER MONITORING. ACCESS TO GROUNDWATER WOULD BE CONTROLLED
THROUGH DEED RESTRICTIONS. PUBLIC WATER IS AVAILABLE THROUGHOUT THE
AREA. LONG-TERM MONITORING WOULD BE PERFORMED AS DESCRIBED IN
ALTERNATIVE 1, NO ACTION.
SOILS, SOLID WASTES, AND SLUDGE
LIMITED ACTION FOR SOILS, SOLID WASTES, AND SLUDGE AT EACH SITE WOULD
CONSIST OF ACCESS CONTROL THROUGH FENCING AND DEED RESTRICTIONS. THE
AREAS CONTAINING SOILS, SOLID WASTES, AND SLUDGE WITH PCB CONCENTRATIONS
EXCEEDING 25 PPM WOULD BE FENCED. THE FENCE WOULD CONSIST OF SIX-FOOT
HIGH WELDED WIRE WITH ONE STRAND OF BARBED WIRE EXTENDING ALONG THE TOP.
THE SITES WOULD BE POSTED AND GATES WOULD BE KEPT LOCKED. IN ADDITION
TO FENCING, LEGAL ACTIONS WOULD BE IMPLEMENTED TO PROVIDE DEED
RESTRICTIONS CONCERNING ACCESS AND FUTURE SITE USE.
7.2.2 EFFECTIVENESS
FENCES INSTALLED AROUND THE AFFECTED AREAS WOULD PREVENT DIRECT HUMAN
CONTACT WITH AFFECTED MATERIAL, BUT WOULD NOT REDUCE POTENTIAL MIGRATION
BY SURFACE EROSION. INHALATION OF WASTE CONSTITUENTS WAS NOT FOUND IN
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THE RI TO BE AN EXPOSURE PATHWAY.
LIMITED ACTION ON GROUNDWATER WOULD RESTRICT FUTURE USE AND CONSUMPTION
OF GROUNDWATER IN AND AROUND THE AFFECTED AREAS (PLANT, BREAZEALE,
DODGENS, AND CROSS ROADS) THROUGH INSTITUTIONAL CONTROLS. AS DISCUSSED
IN SECTION 7.1.2, NATURAL ATTENUATION OF WASTE CONSTITUENTS IN FRACTURED
BEDROCK MAY CONTINUE TO LOWER THE CONCENTRATIONS OF THOSE CONSTITUENTS
AND THOSE OF THEIR DEGRADATION PRODUCTS.
7.3 ALTERNATIVE 3: LIMITED ACTION WITH CONTAINMENT OF SOLIDS
7.3.1 DESCRIPTION
THIS ALTERNATIVE COMBINES THE INSTITUTIONAL CONTROLS FOR GROUNDWATER AND
SOLID MATERIALS THAT ARE DESCRIBED IN SECTION 7.2.1, WITH CONTAINMENT OF
AFFECTED SOLID MATERIALS BY CAPPING. TABLE 7-1 CONTAINS ESTIMATED
VOLUMES OF AFFECTED MATERIAL. THIS ALTERNATIVE WOULD CONTAIN IN PLACE
THE TOTAL VOLUME OF SOLIDS. THE PURPOSE OF CONTAINMENT IS TO REDUCE
CONTACT OF WASTE CONSTITUENTS WITH RECEPTOR POPULATIONS AND THE
ENVIRONMENT. REDUCTION WOULD BE ACCOMPLISHED BY MINIMIZING INFILTRATION
OF WASTE CONSTITUENTS INTO THE GROUNDWATER, INHIBITING EROSION OF THE
CONSTITUENTS, AND BY PROVIDING A BARRIER TO DIRECT CONTACT.
CONTAINMENT WOULD LEAVE AFFECTED SOILS IN PLACE. A CAP OVER AFFECTED
MATERIALS AT THE SURFACE WOULD REDUCE CONTACT BETWEEN PERCOLATING WATER
AND WASTE CONSTITUENTS, THEREBY REDUCING LEACHATE PRODUCTION. IN
ADDITION, A CAP INSTALLED OVER THE AFFECTED MATERIALS WOULD PREVENT
EROSION OF WASTE CONSTITUENTS BY WIND OR WATER. SITES REQUIRING
CONTAINMENT WOULD BE GRADED TO PROVIDE SURFACE DRAINAGE AROUND AND AWAY
FROM CONTAINED SOLIDS. A CONTAINMENT COVER WOULD REQUIRE MAINTENANCE
AND INSPECTION.
THE ALTERNATIVE WOULD BE IMPLEMENTED AT THE PLANT AND OFF-SITE AREAS.
THE FOLLOWING TWO DESIGNS ARE BEING CONSIDERED FOR THE COVER:
OPTION 3A - COMPOSITE COVER
THE COMPOSITE COVER OPTION WOULD INCLUDE A CAP CONSISTING OF THE
FOLLOWING COMPONENTS:
*
12 INCHES OF TOPSOIL
*
2 FEET OF COMPACTED CLAY
*
A LAYER OF GEOTEXTILE MATERIAL
THE CLAY LAYER WOULD BE COMPACTED TO REDUCE PERMEABILITY TO LESS THAN
1 X (10-7) CM/SEC. THE FINAL SURFACE CONTOURS OF THE CAP WOULD BE
GRADED TO PROMOTE RUNOFF RATHER THAN INFILTRATION DURING RAINFALL.
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THE COMPOSITE COVER WOULD BE SOWN WITH SHALLOW ROOTED GRASSES TO
MINIMIZE CAP EROSION. GRASSES WOULD BE SELECTED THAT PREVENTED
PENETRATION OF THE CLAY LAYER BY THE ELEMENTS.
OPTION 3B - MULTI-MEDIA COVER
THE MULTI-MEDIA COVER OPTION WOULD INCLUDE A CAP CONSISTING OF THE
FOLLOWING COMPONENTS:
*
6 INCHES OF TOPSOIL
*
18 INCHES OF ROOTING ZONE SOIL
*
1 LAYER OF GEOTEXTILE
*
1 LAYER OF DRAINAGE MATERIAL
*
1 LAYER OF FLEXIBLE MEMBRANE LINER
*
2 FEET OF CLAY
THE MULTI-MEDIA COVER DESIGN COMPLIES WITH SC DHEC REQUIREMENTS FOR
HAZARDOUS WASTE COVER SYSTEMS AND WOULD PERFORM IN ACCORDANCE WITH US
EPA MINIMUM TECHNOLOGY GUIDANCE. LIKE THE COMPOSITE COVER OPTION, THE
MULTI-MEDIA COVER WOULD BE GRADED TO PROMOTE SURFACE DRAINAGE AND SOWN
WITH SHALLOW-ROOTED GRASSES.
CONTAINMENT OF SLUDGE IN THE ACTIVE LAGOON WOULD BE ACCOMPLISHED BY
PLACEMENT OF A BENTONITE COVER. THE BENTONITE COVER WOULD BE
APPROXIMATELY SIX INCHES THICK AND WOULD BE PLACED OVER THE ENTIRE
SLUDGE LAYER IN THE LAGOON. THIS ACTION WOULD BE TAKEN TO SUPPLEMENT
THE EXISTING UNCONSOLIDATED BENTONITE COVER AND WOULD ENABLE THE PRESENT
TREATMENT SYSTEM TO CONTINUE OPERATION. SLUDGE IN THE INACTIVE LAGOON
WOULD BE COVERED IN THE SAME MANNER.
7.3.2 EFFECTIVENESS
THE SHORT-TERM EFFECTIVENESS OF ALTERNATIVE 3 WOULD BE PROVIDED BY USING
CONSTRUCTION METHODS AND PRACTICES THAT MINIMIZE THE MOVEMENT OF WASTE
CONSTITUENTS. LONG-TERM PROTECTIVENESS WOULD BE PROVIDED THROUGH
NATURAL DEGRADATION OF WASTE CONSTITUENTS AND BY CONTROLLING THE
FOLLOWING MIGRATION ROUTES:
*
PARTICULATE RELEASES TO THE AIR,
*
DIRECT CONTACT WITH AFFECTED MEDIA,
*
GROUND SURFACE RUNOFF OF AFFECTED MATERIALS,
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*
SURFACE WATER INFILTRATION INTO AFFECTED SOIL OR WASTES
AND SUBSEQUENT, MIGRATION THROUGH GROUNDWATER.
COMPARED TO A COMPOSITE COVER, THE MULTI-MEDIA COVER PROVIDES GREATER
LONG-TERM EFFECTIVENESS BY SUPPLYING A MORE SUBSTANTIAL BARRIER TO
INFILTRATION. RESULTS OF THE HYDROLOGIC EVALUATION OF LANDFILL
PERFORMANCE (HELP) COMPUTER PROGRAM SHOW THAT OPTION A WOULD REDUCE
INFILTRATION BY APPROXIMATELY 92 PERCENT AND OPTION B WOULD REDUCE
INFILTRATION BY APPROXIMATELY 99 PERCENT. HOWEVER, SINCE THE PRIMARY
OBJECTIVE IS ELIMINATION OF DIRECT CONTACT WITH WASTE CONSTITUENTS, THE
SMALL INCREASE IN INFILTRATION ALLOWED BY A COMPOSITE COVER DOES NOT
ELIMINATE IT FROM CONSIDERATION.
MONITORING EFFLUENT FROM THE LAGOON HAS SHOWN THE COVER TO BE EFFECTIVE
IN ELIMINATING MIGRATION OF PCBS THROUGH WATER. PLACEMENT OF ADDITIONAL
BENTONITE WOULD BE CARRIED OUT TO SUPPLEMENT THE EXISTING COVER.
7.4 ALTERNATIVE 4: LIMITED ACTION WITH CONTAINMENT OF SOIL AND SLUDGE
AND OFF-SITE DISPOSAL OF SOLID WASTES
7.4.1 DESCRIPTION
ALTERNATIVE 4 CONSISTS OF THE FOLLOWING COMPONENTS: LIMITED ACTION FOR
GROUNDWATER COMBINED WITH CAPPING OF SOIL AND SLUDGE AS DESCRIBED IN
SECTIONS 7.2.1 AND 7.3.1 AND OFF-SITE DISPOSAL OF SOLID WASTES. ON THE
BASIS OF INFORMATION COLLECTED DURING THE RI PHASE I, APPROXIMATELY
2,900 CUBIC YARDS OF SOLID WASTES WOULD BE EXCAVATED, PRE-PROCESSED, AND
TRANSPORTED OFF SITE FOR TREATMENT BY THERMAL DESTRUCTION OR DISPOSAL IN
A TSCA SECURE CHEMICAL LANDFILL. USING A TYPICAL DENSITY OF 1.3
TONS/CUBIC YARD, THE TOTAL WEIGHT OF EXCAVATED SOLID WASTE WOULD BE
APPROXIMATELY 3,800 TONS. THIS AVERAGE DENSITY WAS APPROXIMATELY THAT
OF SOLID WASTES REMOVED FROM AREA D OF THE PLANT SITE. ALL REMAINING
SOIL AND SLUDGE VOLUMES WOULD BE CAPPED.
THIS ALTERNATIVE INCLUDES OFF-SITE DISPOSAL BY BOTH INCINERATION AND
LANDFILLING TO INCREASE IMPLEMENTABILITY THROUGH MAXIMIZING THE
POTENTIAL FOR AVAILABLE COMMERCIAL TREATMENT AND DISPOSAL CAPACITY.
THERMAL DESTRUCTION OF WASTES WOULD OCCUR IN A PERMITTED ROTARY KILN
INCINERATOR OWNED BY A COMMERCIAL VENDOR. TO ANALYZE THIS ALTERNATIVE,
AN ASSUMPTION WILL BE MADE THAT APPROXIMATELY TEN PERCENT OF THE SOLID
WASTE (380 TONS) WOULD BE HAULED TO AN INCINERATOR. THE INCINERATOR
NEAREST THE SITE IS APPROXIMATELY 850 MILES AWAY. AN ASSUMPTION WILL
ALSO BE MADE THAT APPROXIMATELY 90 PERCENT (3,400 TONS) OF SOLID WASTES
WOULD BE HAULED TO A LANDFILL. THE LANDFILL CONSIDERED IS APPROXIMATELY
500 MILES FROM THE SITE.
PERCENTAGES OF SOLID WASTE SUITABLE FOR LANDFILLING AND INCINERATION ARE
BASED ON THE CLASSIFICATIONS OF WASTES EXCAVATED FROM AREA D OF THE
PLANT SITE. THESE WASTES WERE EXCAVATED AND SEGREGATED ACCORDING TO
SIZE AND TYPE.
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THE SELECTED WASTE HAULER AND DISPOSAL FACILITY WILL BE IN COMPLIANCE
WITH APPLICABLE FEDERAL (RCRA AND TSCA) AND APPROPRIATE STATE
ENVIRONMENTAL AND PUBLIC HEALTH STATUTES. IF NECESSARY, RCRA MANIFESTS
REQUIRED UNDER 40 CFR PARTS 262 AND 263 WILL BE COMPLETED FOR ALL WASTES
SHIPPED OFF-SITE. IN ADDITION, THE FACILITY WILL COMPLY WITH APPLICABLE
HAZARDOUS WASTE GENERATOR REQUIREMENTS UNDER 40 CFR PART 262.
THIS ALTERNATIVE WOULD BE IMPLEMENTED AT THE PLANT AND OFF-SITE AREAS.
7.4.2 EFFECTIVENESS
THE EFFECTIVENESS OF LIMITED GROUNDWATER ACTION WAS DISCUSSED IN THE
DESCRIPTION FOR ALTERNATIVE 2, AND IS THE SAME FOR THIS ALTERNATIVE.
SHORT-TERM EFFECTIVENESS DURING WASTE REMOVAL AND SOIL CAPPING IS
PROVIDED BY CONSTRUCTION TECHNIQUES THAT MINIMIZE HANDLING AND REDUCE
THE DISPERSION OF WASTE CONSTITUENTS DURING CONTAINMENT AND EXCAVATION
ACTIVITIES. EXCAVATION AND MOVEMENT OF SOLID WASTES WOULD RESULT IN A
PERIOD DURING WHICH THE POTENTIAL FOR ADDITIONAL EXPOSURE WOULD EXIST.
USE OF MEASURES FOR RUN-OFF PREVENTION AND DUST CONTROL WOULD PROVIDE
PROTECTION TO HUMAN HEALTH AND THE ENVIRONMENT DURING CONSTRUCTION.
NEITHER TOXICITY NOR VOLUME OF GROUNDWATER, SOIL, OR SLUDGE MATERIALS
WOULD BE REDUCED BY IMPLEMENTATION OF THIS ALTERNATIVE.
OFF-SITE MANAGEMENT OF WASTES BY LANDFILLING WOULD NOT REDUCE THE
TOXICITY OR VOLUME OF THE MATERIALS. MOBILITY OF WASTE CONSTITUENTS
REMOVED WOULD BE REDUCED. HAULING WASTES OFF-SITE CO POTENTIALLY EXPOSE
THOSE PERSONS USING THE SAME ROADS, OR LIVING OR WORKING ALONG THE
ROUTE, TO AFFECTED MATERIALS.
LONG-TERM EFFECTIVENESS WOULD BE PROVIDED BY PROPER CAP MAINTENANCE AND
THE REMEDIATION ACHIEVED BY WASTE REMOVAL AND OFF-SITE TREATMENT OR
DISPOSAL. VOLUME AND TOXICITY OF AFFECTED SOIL AND SLUDGE WOULD NOT BE
ALTERED BY THE TECHNIQUES USED IN THIS ALTERNATIVE.
FOR CONTAINMENT OF SOILS AND SLUDGES, LONG-TERM PROTECTION WOULD BE
PROVIDED-THROUGH THE CONTROL OF SEVERAL MIGRATION ROUTES AS FOLLOWS:
*
PARTICULATE RELEASES TO THE AIR,
*
DIRECT CONTACT WITH AFFECTED MEDIA,
*
GROUND SURFACE RUNOFF OF AFFECTED SEDIMENTS,
*
SURFACE WATER INFILTRATION INTO AFFECTED SOIL OR WASTES
AND SUBSEQUENT MIGRATION THROUGH GROUNDWATER.
HOWEVER, THIS ALTERNATIVE WOULD NOT CHANGE THE CHARACTERISTICS OF THE
AFFECTED SOIL AND SLUDGE AS DESCRIBED IN SECTION 7.3.1.
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7.5 ALTERNATIVE 5: LIMITED GROUNDWATER ACTION WITH ON-SITE DISPOSAL OF
SOLIDS
7.5.1 DESCRIPTION
THE COMPONENTS OF THIS ALTERNATIVE INCLUDE THE MEASURES DESCRIBED IN
SECTION 7.2.1 FOR LIMITED ACTION ON GROUNDWATER AND EXCAVATION AND
DISPOSAL OF AFFECTED SOLID MATERIALS: SOIL, SLUDGE, AND SOLID WASTES.
SLUDGE FROM THE ACTIVE LAGOON WOULD BE DREDGED AND MECHANICALLY
DEWATERED. SOILS AND SOLID WASTES CONTAINING GREATER THAN 25 PPM OF
PCBS WOULD BE EXCAVATED AND TRANSPORTED TO AN ON-SITE TSCA UNIT DESIGNED
AND CONSTRUCTED SPECIFICALLY FOR THE DISPOSAL OF THESE MATERIALS. A
LANDFILL CLOSURE WOULD BE IMPLEMENTED AFTER THE DISPOSAL IS COMPLETE.
THIS ALTERNATIVE WOULD BE IMPLEMENTED AT ALL LOCATIONS.
EVALUATION OF ALTERNATIVE 5 IS BASED ON EXCAVATION AND DISPOSAL OF THE
FOLLOWING VOLUMES OF AFFECTED MATERIALS:
AN ON-SITE, DOUBLE-LINED LANDFILL WOULD BE CONSTRUCTED FOR DISPOSAL OF
AFFECTED SOLIDS FOR A CAPACITY OF 93,000 CUBIC YARDS, WHICH TAKES INTO
ACCOUNT A 25 PERCENT EXPANSION OF 74,100 CUBIC YARDS OF SOLIDS AFTER
EXCAVATION. LANDFILL DIMENSIONS WOULD BE APPROXIMATELY 400 FEET BY 300
FEET AT GRADE. THE DEPTH OF EXCAVATION BELOW GROUND SURFACE WOULD BE
APPROXIMATELY 14 FEET, AND THE BERM HEIGHT AROUND THE LANDFILL WOULD BE
APPROXIMATELY 17 FEET.
THE LANDFILL WOULD BE CONSTRUCTED ACCORDING TO REGULATORY REQUIREMENTS
OF THE STATE OF SOUTH CAROLINA AND THE US EPA. THESE REQUIREMENTS
INCLUDE CONSTRUCTION OF A DOUBLE LINER WITH A LEACHATE COLLECTION SYSTEM
ABOVE AND BETWEEN THE LINERS. THE TOP LINER MUST PREVENT THE MIGRATION
OF WASTE CONSTITUENTS INTO THE LOWER LINER. THE BOTTOM LINER MUST
PREVENT MIGRATION OF WASTE CONSTITUENTS. SOUTH CAROLINA CODE
R.61-79.264.301 (C) REQUIRES A THREE-FEET THICK LAYER OF RECOMPACTED
CLAY OR OTHER NATURAL MATERIAL AS A BOTTOM LINER. THE PERMEABILITY MUST
BE NO MORE THAN 1 X (10-7) CENTIMETERS PER SECOND. THE LANDFILL CAP
MUST BE LESS PERMEABLE THAN THE SOILS IMMEDIATELY BELOW THE LANDFILL.
LANDFILL OPERATION AND MAINTENANCE (O&M) WOULD INCLUDE A NUMBER OF TASKS
NECESSARY TO PROTECT THE INTEGRITY OF THE DISPOSAL UNIT. QUARTERLY
MAINTENANCE WOULD BE PERFORMED ON THE ACCESS ROAD, THE LEACHATE
COLLECTION AND TREATMENT SYSTEM, AND THE LANDFILL, WHICH IS EXPECTED TO
COVER APPROXIMATELY THREE ACRES. GROUNDWATER MONITORING WOULD BE
PERFORMED SEMIANNUALLY. THE ACTIVE MAINTENANCE PERIOD USED FOR
ESTIMATING O&M COSTS IS 30 YEARS.
7.5.2 EFFECTIVENESS
THE EFFECTIVENESS OF LIMITED ACTION ON GROUNDWATER WAS DISCUSSED IN
SECTION 7.2.2 AND IS SIMILAR TO THAT PROVIDED BY THIS ALTERNATIVE. THE
SHORT-TERM EFFECTIVENESS, DURING IMPLEMENTATION OF THIS ALTERNATIVE FOR
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EXCAVATION AND ON-SITE DISPOSAL OF SOLID MATERIALS, WOULD BE PROVIDED BY
THE USE OF EXCAVATION TECHNIQUES THAT MINIMIZE HANDLING AND REDUCE THE
DISPERSION OF WASTE CONSTITUENTS. THE LARGE VOLUME OF MATERIAL THAT
WOULD BE MOVED WOULD RESULT IN AN EXTENDED PERIOD DURING WHICH THE
POTENTIAL FOR EXPOSURE WOULD EXIST. USE OF MEASURES FOR THE PREVENTION
OF RUN-OFF AND THE CONTROL OF DUST WOULD PROVIDE SOME PROTECTION TO
HUMAN HEALTH AND THE ENVIRONMENT DURING CONSTRUCTION.
THE LONG-TERM EFFECTIVENESS OF THIS ALTERNATIVE WOULD BE PROVIDED BY
PROPER MAINTENANCE OF THE ON-SITE LANDFILL. NEITHER THE VOLUME NOR THE
TOXICITY OF AFFECTED MATERIALS WOULD BE ALTERED BY THE TECHNIQUES USED
IN THIS ALTERNATIVE. REMOVAL OF SOURCE MATERIALS WOULD PREVENT FURTHER
MIGRATION OF CONTAMINANTS INTO THE AQUIFER.
7.6 ALTERNATIVE 6: LIMITED GROUNDWATER ACTION WITH OFF-SITE DISPOSAL OF
SOLIDS
7.6.1 ALTERNATIVE 6 CONSISTS OF LIMITED ACTION ON GROUNDWATER AS
DESCRIBED IN SECTION 7.2.1; EXCAVATION OF AFFECTED SOLID MATERIALS, AS
DESCRIBED IN SECTION 7.5.1, AND OFF-SITE DISPOSAL IN A SECURE TSCA
LANDFILL. THE CONCEPTUAL LAYOUT OF THIS ALTERNATIVE WOULD BE THE SAME
AS THAT FOR ALTERNATIVE 5, EXCEPT THAT ONCE EXCAVATED, THE MATERIAL
WOULD BE TAKEN OFF-SITE.
SOLID MATERIALS WOULD BE EXCAVATED, LOADED DIRECTLY ONTO TRUCKS, AND
TRANSPORTED TO THE SELECTED LANDFILL. LAGOON SLUDGE WOULD BE EXCAVATED,
DEWATERED, AND STOCKPILED. THE STOCKPILED SLUDGE WOULD THEN BE HAULED
OFF-SITE. WATER COLLECTED DURING SLUDGE DEWATERING WOULD BE TRANSPORTED
OFF-SITE FOR TREATMENT.
THE SELECTED WASTE HAULER AND THE DISPOSAL FACILITY WILL BE IN
COMPLIANCE WITH APPLICABLE FEDERAL AND STATE ENVIRONMENTAL AND PUBLIC
HEALTH STATUTES. IF NECESSARY, RCRA MANIFESTS REQUIRED UNDER 40 CFR
PARTS 262 AND 263 WILL BE COMPLETED FOR ALL WASTES SHIPPED OFF-SITE. IN
ADDITION, THE FACILITY WILL COMPLY WITH APPLICABLE HAZARDOUS WASTE
GENERATOR REQUIREMENTS UNDER 40 CFR PARTS 262.
TRANSPORTING VEHICLES WILL BE APPROVED BY DOT AND WILL DISPLAY THE
PROPER DOT PLACARD. FOR ESTIMATED COST, IT IS ASSUMED THAT 90 PERCENT
OF THE MATERIAL CAN BE HANDLED BY A FACILITY APPROXIMATELY 500 MILES
FROM THE SANGAMO PLANT SITE. THE REMAINING TEN PERCENT OF THE SOLID
WASTES WOULD BE TRANSPORTED APPROXIMATELY 850 MILES TO AN INCINERATOR.
7.6.2 EFFECTIVENESS
THE EFFECTIVENESS OF EXCAVATION COMBINED WITH LIMITED ACTION ON
GROUNDWATER WAS DISCUSSED IN THE DESCRIPTION FOR ALTERNATIVE 5.
REMAINS UNCHANGED FOR THIS ALTERNATIVE.
IT
OFF-SITE MANAGEMENT OF WASTES BY LANDFILLING WOULD NOT REDUCE THE
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TOXICITY OR VOLUME OF MATERIALS. HOWEVER, LONG-TERM MOBILITY OF WASTE
CONSTITUENTS WOULD BE REDUCED. HAULING WASTES OFF-SITE COULD
POTENTIALLY EXPOSE THOSE PERSONS USING THE SAME ROADS, OR LIVING OR
WORKING ALONG THE ROUTE, TO AFFECTED MATERIALS.
7.7 ALTERNATIVE 7: TREATMENT OF GROUNDWATER WITH ON-SITE DISPOSAL OF
SOLIDS
7.7.1 DESCRIPTION
ALTERNATIVE 7 IS COMPRISED OF THE FOLLOWING TWO COMPONENTS:
1)
SOLID MATERIAL REMEDIATION WHICH INCLUDES EXCAVATION AND
DISPOSAL IN A SECURE TSCA LANDFILL CONSTRUCTED ONSITE AS
DESCRIBED IN SECTION 7.5.1. THIS REMEDIATION TECHNIQUE
HAS BEEN DISCUSSED AND NEEDS NO FURTHER EXPLANATION FOR
THE PURPOSES OF THIS ALTERNATIVE.
2)
GROUNDWATER REMEDIATION WHICH CONSISTS OF GROUNDWATER
COLLECTION, TREATMENT, AND DISCHARGE AT THE PLANT,
BREAZEALE, DODGENS AND CROSS ROADS SITES.
THE GROUNDWATER REMEDIATION TECHNIQUES DISCUSSED IN THIS SECTION ARE
APPLICABLE TO THE PLANT, BREAZEALE, DODGENS AND CROSS ROADS SITES.
GROUNDWATER COLLECTION AND TREATMENT IS NOT NECESSARY AT THE JOHN
TROTTER, NIX AND WELBORN SITES. A DESCRIPTION OF THE COMPONENTS OF
LIMITED GROUNDWATER ACTION THAT WOULD BE PERFORMED AT THESE THREE
OFF-SITE AREAS APPEARS IN SECTION 7.2.1. EXCAVATION OF ALL SOLID
MATERIALS CONTAINING GREATER THAN 25 PPM PCBS WOULD OCCUR AT EACH
AFFECTED LOCATION.
AS FORMULATED FOR THIS ALTERNATIVE, GROUNDWATER WOULD BE COLLECTED TO
THE EXTENT POSSIBLE BY USE OF RECOVERY WELLS. RECOVERY WELLS WOULD BE
INSTALLED DOWNGRADIENT OF THE SITES. BY PUMPING EACH WELL, AN EFFORT
WOULD BE MADE TO CREATE A HYDRAULIC BARRIER.
WHERE PUMPING OF INDIVIDUAL RECOVERY WELLS IS SUCCESSFUL IN REMOVING
AFFECTED GROUNDWATER, IT ACCELERATES THE NATURAL FLUSHING OF WASTE
CONSTITUENTS SORBED ON THE SOIL IN THE AQUIFER BY INCREASING THE FLOW
RATE OF RELATIVELY CLEAN WATER FROM AREAS UPGRADIENT OF THE CONSTITUENT
SOURCE THROUGH THE AFFECTED AREAS.
SANGAMO PLANT SITE
GROUNDWATER AT THE SANGAMO PLANT SITE OCCURS PRIMARILY WITHIN THE JOINT
AND FRACTURE SYSTEM OF THE BEDROCK. GROUNDWATER FLOW WITHIN THE BEDROCK
AT THE SANGAMO PLANT SITE IS LIMITED BY THE SIZE, ORIENTATION, AND
INTERCONNECTION OF OPEN JOINTS AND FRACTURES. THESE WELLS MAY NOT
REMOVE CONSTITUENTS THAT ARE HEAVIER THAN WATER. GROUNDWATER DISCHARGE
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FROM WELLS SURROUNDING THE RIDGE WOULD CONTAIN PRIMARILY VOCS. THIS
WATER WOULD BE TREATED BY AIR STRIPPING. GROUNDWATER DOWNGRADIENT OF
AREAS A, B, E, AND THE WASTE WATER TREATMENT FACILITY WOULD BE TREATED
BY CARBON ADSORPTION. IN THIS AREA, RI DATA SHOWED PCBS IN GROUNDWATER
COLLECTED FROM 10 OF 17 WELLS. VOCS HAVE BEEN DETECTED IN A MAJORITY OF
THESE WELLS. TREATED WATER WOULD BE DISCHARGED INTO TOWN CREEK.
BREAZEALE SITE
THE ASSUMED PUMPING SCHEME FOR THE BREAZEALE SITE CONSISTS OF
GROUNDWATER EXTRACTION WELLS SCREENED IN THE SATURATED PORTIONS OF THE
SAPROLITE AND FLOODPLAIN DEPOSITS.
GROUNDWATER DISCHARGE WOULD CONTAIN VOCS AND WOULD BE TREATED THROUGH
AIR STRIPPING. TREATED WATER WOULD BE DISCHARGED INTO WOLF CREEK.
DODGENS SITE
THE ASSUMED PUMPING SCHEME FOR THE DODGENS SITE CONSISTS OF GROUNDWATER
EXTRACTION WELLS SCREENED IN THE SATURATED PORTIONS OF THE SAPROLITE.
GROUNDWATER DISCHARGE MAY CONTAIN VOCS AND ONE SEMI-VOLATILE. COLLECTED
GROUNDWATER WOULD BE TREATED THROUGH AIR STRIPPING AND CARBON
ADSORPTION, IF NECESSARY. TREATED WATER WOULD BE DISCHARGED TO MIDDLE
FORK TWELVEMILE CREEK.
7.7.2 EFFECTIVENESS
THE EFFECTIVENESS PROVIDED BY THIS ALTERNATIVE IS RELATED TO THREE
CRITERIA:
*
THE EXTENT TO WHICH THE GROUNDWATER COLLECTION SYSTEM IS
CAPABLE OF PREVENTING MOVEMENT OF AFFECTED GROUNDWATER
FROM THE PLANT, BREAZEALE, CROSS ROADS AND DODGENS SITES,
*
THE GRADUAL REDUCTION IN THE TOXICITY OF GROUNDWATER BY
TREATMENT,
*
REDUCTION OF VOLUME OF THE AFFECTED MATERIAL, AND
*
PROPER DESIGN, CONSTRUCTION, AND MAINTENANCE OF THE LAND
DISPOSAL UNIT.
THE SHORT-TERM EFFECTIVENESS PROVIDED DURING CONSTRUCTION OF THIS
ALTERNATIVE FOR GROUNDWATER COLLECTION AND ON-SITE DISPOSAL OF SOLID
MATERIALS WOULD BE PROVIDED BY CONSTRUCTION TECHNIQUES AND WELL
INSTALLATION METHODS THAT REDUCE THE MIGRATION OF WASTE CONSTITUENTS.
THE LARGE VOLUME OF MATERIAL TO BE MOVED DURING EXCAVATION WOULD RESULT
IN A PERIOD DURING WHICH A POTENTIAL FOR EXPOSURE WOULD EXIST. USE OF
MEASURES FOR THE PREVENTION OF RUN-OFF AND THE CONTROL OF DUST WOULD
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PROVIDE A MEASURE OF PROTECTION TO HUMAN HEALTH AND THE ENVIRONMENT
DURING CONSTRUCTION. THE SOLID MATERIALS WOULD NOT BE REDUCED IN EITHER
TOXICITY OR VOLUME BY THE IMPLEMENTATION OF THIS ALTERNATIVE.
THE ON-SITE LAND DISPOSAL COMPONENT OF THIS ALTERNATIVE WOULD BE
EFFECTIVE IN PROTECTING HUMAN HEALTH AND THE ENVIRONMENT FROM EXPOSURE
TO WASTE CONSTITUENTS NEAR THE LAND DISPOSAL UNIT. EFFECTIVENESS WOULD
BE MAINTAINED BY USE OF A PROGRAM THAT INCLUDES CAP AND COVER CARE AT
THE LANDFILL, GROUNDWATER MONITORING, AND LEACHATE TREATMENT.
7.8 ALTERNATIVE 8: LIMITED GROUNDWATER ACTION WITH ON-SITE TREATMENT AND
DISPOSAL OF SOLIDS
7.8.1 DESCRIPTION
THIS ALTERNATIVE CONSISTS OF LIMITED ACTION ON GROUNDWATER, AS DESCRIBED
IN SECTION 7.2.1, COUPLED WITH THE EXCAVATION OF SOLID MATERIALS AND
TREATMENT OF THE MATERIALS IN AN ON-SITE TREATMENT SYSTEM. FOR
SCREENING PURPOSES, FOUR TREATMENT TECHNOLOGIES WERE CONSIDERED: THERMAL
DESTRUCTION, THERMAL SEPARATION, CHEMICAL DECHLORINATION, AND
STABILIZATION.
EACH OF THE FOLLOWING REPRESENTATIVE PROCESS OPTIONS HAS BEEN SELECTED
BASED ON COMMERCIAL AVAILABILITY AND/OR HISTORY OF PRIOR FULL-SCALE
APPLICATION:
OPTION 8A:
OPTION 8B:
OPTION 8C:
OPTION 8D:
THERMAL DESTRUCTION - ROTARY KILN INCINERATION
THERMAL SEPARATION - LOW TEMPERATURE THERMAL
STRIPPING
CHEMICAL DECHLORINATION - GLYCOLATE DECHLORINATION
PHYSICAL STABILIZATION SOLIDIFICATION/FIXATION
THE FIRST STEP IN THIS ALTERNATIVE WOULD INCLUDE EXCAVATION OF SOLID
MATERIALS AFFECTED WITH GREATER THAN 1 PPM, 10 PPM, OR 25 PPM PCBS AS
APPROPRIATE. FOLLOWING EXCAVATION, THE MATERIALS WOULD BE TEMPORARILY
STOCKPILED ON THE PLANT SITE. THIS MATERIAL CONSISTS OF 2,900 CUBIC
YARDS OF SOLID WASTE AND 48,200 CUBIC YARDS OF SOILS AND SEDIMENTS.
SEDIMENTS WOULD BE DREDGED AND DEWATERED PRIOR TO TRANSPORT TO THE
TREATMENT AREA. LIQUIDS PRODUCED DURING DEWATERING WOULD BE TEMPORARILY
STORED IN TANKS AND THEN TRANSPORTED FOR TREATMENT IN THE LEACHATE
TREATMENT UNIT AT THE ON-SITE TSCA LANDFILL. THE AVERAGE HAUL DISTANCE
FROM ON-SITE EXCAVATION AREAS SITE WOULD BE LESS THAN APPROXIMATELY
ONE-HALF MILE. THE AVERAGE HAUL DISTANCE FROM REMOTE SITE EXCAVATION
AREAS WOULD BE APPROXIMATELY 2.5 MILES. THE VOLUME OF THE TREATMENT
RESIDUALS WOULD BE DETERMINED DURING A TREATABILITY STUDY. LIMITED
FIELD TRIALS MAY BE REQUIRED TO CONFIRM TREATMENT EFFECTIVENESS AND TO
CHARACTERIZE TREATMENT RESIDUALS.
EACH OF THE TREATMENT PROCESS OPTIONS WOULD REQUIRE PRE-PROCESSING OF
THE SOLIDS TO REMOVE OVERSIZED ITEMS AND TO REDUCE THE PARTICLE SIZE.
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THE COST AND ANALYSIS OF THIS ALTERNATIVE IS BASED IN PART ON THE
ASSUMPTION THAT A PORTION OF THE TOTAL MASS OF SOLIDS WOULD BE REJECTED
DURING PREPROCESSING. THE ASSUMPTION OF A ONE PERCENT REJECTION RATE IS
USED BECAUSE MUCH OF THE AFFECTED AREAS ARE NOT COVERED WITH THICK
STANDS OF TREES.
THESE MATERIALS WOULD REQUIRE OFF-SITE DISPOSAL AND/OR TREATMENT AS A
TSCA REGULATED WASTE IN A PERMITTED LANDFILL.
UNDER ALL FOUR TREATMENT OPTIONS, EXCAVATED AREAS WOULD BE BACKFILLED
WITH NATIVE SOIL, GRADED, AND RESTORED TO SUPPORT VEGETATION. A
LONG-TERM GROUNDWATER MONITORING PROGRAM WOULD BE IMPLEMENTED, AS
DESCRIBED IN ALTERNATIVE 1.
OPTION 8A: THERMAL DESTRUCTION
THIS OPTION INCLUDES USE OF A TRANSPORTABLE ROTARY KILN INCINERATOR THAT
WOULD BE LOCATED AT THE SITE BY A COMMERCIAL VENDOR. THE UNIT WOULD
MEET THE SUBSTANTIVE REQUIREMENTS OF ALL APPLICABLE PERMITS.
THE SYSTEM WOULD CONSIST OF THE FOLLOWING TYPICAL UNIT OPERATIONS:
*
*
*
*
*
*
*
MATERIAL PREPROCESSING/SORTING
ROTARY KILN INCINERATOR
ASH HANDLING/STORAGE
SECONDARY COMBUSTION OF OFF-GASES
BAGHOUSE DUST COLLECTION
WET SCRUBBER
SCRUBBER WATER TREATMENT
START-UP TESTS REQUIRED PRIOR TO FULL-SCALE OPERATION MAY REQUIRE FROM
SIX MONTHS TO ONE AND ONE-HALF YEARS.
TREATED SCRUBBER WATER COULD BE TEMPORARILY STORED IN A TANK AND
TRANSPORTED TO THE LEACHATE TREATMENT SYSTEM LOCATED AT THE ON-SITE
DISPOSAL UNIT. COMPLETE SYSTEM DETAILS WOULD BE DEVELOPED AS A REMEDIAL
DESIGN TASK.
OPTION 8B: THERMAL SEPARATION
THERMAL SEPARATION IS A PROCESS OPTION RETAINED FROM THE SCREENING OF
THERMAL TREATMENT TECHNOLOGIES.
THERMAL SEPARATION IS A PROCESS IN WHICH SOILS OR SLUDGES WITH ORGANIC
COMPOUNDS ARE HEATED IN A ROTARY DRYER. VOLATILIZED ORGANICS ARE
TRANSFERRED, USING NITROGEN AS THE CARRIER GAS, AND COOLED TO CONDENSE
ORGANIC COMPONENTS. THE CONDENSED COMPONENTS ARE THEN COLLECTED FOR
FURTHER TREATMENT AT AN APPROPRIATE FACILITY.
THE PERMIT REQUIREMENTS FOR THIS SYSTEM ARE STILL BEING DETERMINED BY
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THE OWNER OF THE EQUIPMENT. HOWEVER, AS A "PROCESSING," RATHER THAN A
"DESTRUCTION" METHOD, ATTAINMENT OF THE SUBSTANTIVE REQUIREMENTS OF RCRA
OR TSCA PERMITS MAY NOT BE REQUIRED. THIS SYSTEM WOULD CONSIST OF THE
FOLLOWING TYPICAL UNIT OPERATIONS:
*
*
*
*
*
*
MATERIAL PREPROCESSING/SORTING
ROTARY DRYER THERMAL SEPARATION
CARBON ADSORPTION UNIT (OR COMBUSTION AFTERBURNER)
COOLING AND CONDENSATE TRAIN
OFF-GAS HANDLING TRAILER
RESIDUALS MANAGEMENT UNIT
ON THE BASIS OF PILOT STUDIES, A TREATMENT CAPACITY OF FIVE TONS PER
HOUR CAN BE EXPECTED. ASSUMING A TYPICAL DENSITY OF APPROXIMATELY 1.3
TONS PER CUBIC YARD OF MATERIAL, THE ESTIMATED TIME EXPECTED TO COMPLETE
TREATMENT WOULD BE APPROXIMATELY TWO YEARS. THIS ESTIMATE IS BASED ON
THE USE OF ONE TREATMENT SYSTEM AND 30 PERCENT DOWNTIME.
OPTION 8C: CHEMICAL DECHLORINATION
THE PROPRIETARY KPEG PROCESS IS USED TO REPRESENT CHEMICAL TREATMENT
TECHNOLOGIES APPROPRIATE FOR USE IN TREATING SOILS CONTAINING PCBS AND
OTHER SOLIDS. SINCE THE KPEG PROCESS OPERATES UNDER HIGHLY ALKALINE
CONDITIONS, ALUMINUM SLUDGE AND POSSIBLY OTHER METALS THAT REACT UNDER
THESE CONDITIONS MAY INCREASE THE AMOUNT OF REAGENT REQUIRED BY
COMPETING FOR THE KPEG: THEREFORE, THIS PROCESS OPTION IS NOT CONSIDERED
APPLICABLE FOR TREATMENT OF SLUDGES. CHEMICAL TREATMENT DIRECTED TOWARD
PCBS MAY PROVIDE COINCIDENTAL TREATMENT OF OTHER CHLORINATED VOLATILE
ORGANICS.
THE CHEMICAL TREATMENT SYSTEM WOULD CONSIST OF THE FOLLOWING TYPICAL
OPERATIONS:
*
*
*
*
*
*
MATERIAL PREPROCESSING/SORTING
REAGENT STORAGE
SOLIDS MIXING
SOLIDS REACTION
DECANT AND SOLIDS WASHING
REAGENT RECYCLING AND CONDENSATION
PROCESS WASTEWATERS WOULD BE TEMPORARILY STORED IN TANKS AND LATER
TRANSPORTED TO THE LEACHATE TREATMENT SYSTEM.
THE
THE
(24
THE
PRESENT ESTIMATE BY GALSON RESEARCH CORPORATION (PATENT-HOLDER) OF
ACHIEVABLE TREATMENT RATE USING KPEG IS 250 YD3/D. CONTINUOUS
HR/D) PROCESSING OF THE ENTIRE VOLUME WOULD REQUIRE OVER ONE YEAR.
ESTIMATE ASSUMES A MINIMUM OF 30 PERCENT DOWNTIME FOR THE PROCESS.
OPTION 8D: PHYSICAL STABILIZATION
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PHYSICAL STABILIZATION, OR SOLIDIFICATION/FIXATION WAS CONSIDERED FOR
USE AS A TREATMENT PROCESS FOR SOIL AND SLUDGE. THIS TREATMENT WOULD
REDUCE THE MOBILITY OF WASTE CONSTITUENTS BY BINDING THE SOIL OR SLUDGE
MASS INTO SOLID MATRIX WITH LOW PERMEABILITY THAT RESISTS LEACHING.
THIS ALTERNATIVE WOULD INCREASE THE VOLUME OF AFFECTED MATERIAL.
THE TREATMENT SYSTEM WOULD CONSIST OF THE FOLLOWING TYPICAL UNIT
OPERATIONS:
*
*
*
MATERIAL PREPROCESSING/SORTING
SETTING AGENT STORAGE
PUGMILL MIXING
THE EQUIPMENT REQUIRED FOR SOLIDIFICATION/FIXATION WOULD BE SIMILAR TO
THAT USED FOR CEMENT MIXING. THE TREATED MATERIAL WOULD BE TRANSPORTED
TO THE ON-SITE DISPOSAL UNIT FOR CURING AND DISPOSAL.
SINCE THE PROCESSES USED IN SOLIDIFICATION/FIXATION ARE LOGISTICALLY
SIMILAR TO THOSE OF CEMENT MIXING, THE TIME REQUIRED TO TREAT THE SOIL
AND SLUDGE WOULD NOT VARY SIGNIFICANTLY FROM THAT REQUIRED FOR
EXCAVATION.
7.8.2 EFFECTIVENESS
THE SHORT-TERM PROTECTIVENESS PROVIDED DURING EXCAVATION AND TREATMENT
OF ALL SOLIDS CONTAINING MORE THAN 25 PPM PCBS WOULD BE ACCOMPLISHED BY
USE OF CONSTRUCTION METHODS THAT MINIMIZE TRANSPORT. TEMPORARY BERMS
AND RUN-OFF CONTROL DITCHES WOULD BE USED TO CONTROL TRANSPORT OF
AFFECTED SOILS.
LONG-TERM PROTECTION WOULD BE ACCOMPLISHED BY REMOVAL AND DESTRUCTION OF
WASTE CONSTITUENTS. TOXICITY, MOBILITY, AND VOLUME OF HAZARDOUS
MATERIALS WOULD BE REDUCED BY TREATMENT. ANY POTENTIAL LONG-TERM
SURFACE MIGRATION BY THE LOW CONCENTRATIONS OF WASTE CONSTITUENTS THAT
REMAIN IN PLACE WOULD BE LIMITED BY PLACEMENT OF CLEAN BACKFILL.
GROUNDWATER QUALITY WOULD BE MONITORED BY THE SAMPLING AND ANALYSIS
PROGRAM PROPOSED AS PART OF THE LIMITED ACTION RESPONSE.
FOUR TREATMENT PROCESSES ARE UNDER CONSIDERATION AS PART OF THIS
ALTERNATIVE: ROTARY KILN INCINERATION, THERMAL SEPARATION, GLYCOLATE
DECHLORINATION, AND STABILIZATION/FIXATION. EACH PROCESS HAS BEEN SHOWN
TO BE EFFECTIVE IN REDUCTION OF AT LEAST ONE OF THREE WASTE
CHARACTERISTICS: TOXICITY, MOBILITY OR VOLUME FOR ONE OR MORE OF THE
CONSTITUENTS OF CONCERN. THE COMBINATION OF TREATMENT WITH DISPOSAL OF
RESIDUALS IN AN ON-SITE SECURE LANDFILL WOULD PROVIDE AN EFFECTIVE MEANS
OF REDUCING TOXICITY, MOBILITY, AND VOLUME OF WASTE CONSTITUENTS.
OPTION 8A: THERMAL DESTRUCTION (ROTARY KILN)
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THE EFFECTIVENESS OF INCINERATION AS A TREATMENT PROCESS FOR ORGANIC
COMPOUNDS HAS BEEN DEMONSTRATED AT NUMEROUS SITES. THIS TREATMENT
PROCESS WOULD AFFECT ALL THREE OF THE CHARACTERISTICS FOR PCBS AND
HALOGENATED AND NONHALOGENATED VOLATILES. IT WOULD NOT AFFECT ANY OF
THE THREE CHARACTERISTICS FOR AFFECTED MATERIALS CONTAINING METALS.
OPTION 8B: THERMAL SEPARATION
THERMAL SEPARATION HAS BEEN SHOWN TO HAVE A REMOVAL EFFICIENCY OF GT
99.95 PERCENT FOR PCBS. ITS EFFECTIVENESS FOR TREATMENT OF VOLATILE
ORGANIC COMPOUNDS HAS ALSO BEEN DEMONSTRATED.
IF RESULTS OF CURRENT TESTS USING THIS PROCESS INDICATE APPLICABILITY AT
THIS SITE, A TREATABILITY STUDY WOULD BE PERFORMED ON SAMPLES OF SOIL
AND SLUDGE TAKEN FROM THE SANGAMO PLANT AS PART OF THE REMEDIAL DESIGN
PHASE OF SITE REMEDIATION.
OPTION 8C: GLYCOLATE DECHLORINATION (KPEG)
KPEG, WHILE NOT SPECIFICALLY DESIGNED FOR THE TREATMENT OF ORGANICS
OTHER THAN PCBS, MAY PROVIDE FURTHER PROTECTION BY REMOVING VOLATILE
ORGANIC COMPOUNDS DURING REACTION OR SOIL-WASHING PHASES. IT HAS BEEN
USED AT FULL SCALE FOR TREATMENT OF PCBS IN SOIL, BUT IT HAS NOT BEEN
USED ROUTINELY FOR TREATMENT OF WASTE CONSTITUENTS LIKE THOSE FOUND AT
THE PLANT SITE. THE KPEG PROCESS WOULD NOT AFFECT THE CHARACTERISTICS
OF METALS IN SOIL. A TREATABILITY STUDY WILL BE CONDUCTED TO EVALUATE
ITS OVERALL EFFECTIVENESS ON THE WASTE CONSTITUENTS PRESENT AT THE SITE.
TREATED RESIDUALS FROM EACH OF THE THREE PRECEDING PROCESS OPTIONS WOULD
BE ANALYZED FOR THE PRESENCE OF METALS. RESULTS OF THE RI INDICATE THAT
CONCENTRATION OF METALS WILL NOT EXCEED PERMISSIBLE LIMITS FOR LAND
DISPOSAL.
OPTION 8D: PHYSICAL STABILIZATION
THIS PROCESS, USED IN THE TREATMENT OF INORGANIC COMPOUNDS, HAS A WELL
DOCUMENTED HISTORY OF SUCCESSFULLY IMMOBILIZING WASTE CONSTITUENTS. A
LIMIT TO THE EFFECTIVENESS OF THIS PROCESS IS THE QUANTITY OF OIL AND
GREASE PRESENT IN AFFECTED MEDIA. THE CONCENTRATIONS OF OIL AND GREASE
ARE MORE SIGNIFICANT IN DETERMINING THE APPLICABILITY OF STABILIZATION
THAN THE PCB CONCENTRATIONS IN THE AFFECTED MEDIA. A TREATABILITY STUDY
WOULD HAVE TO BE PERFORMED TO DETERMINE THE EFFECTIVENESS OF THIS
PROCESS ON THE CONCENTRATIONS OF WASTE CONSTITUENTS DETECTED AT THE
SITE.
7.9 ALTERNATIVE 9: TREATMENT OF GROUNDWATER, LIMITED ACTION ON SOILS, IN
SITU TREATMENT OF SOIL, OFF-SITE TREATMENT AND
DISPOSAL OF SOLID WASTES, AND ON-SITE TREATMENT AND
DISPOSAL OF SLUDGE
7.9.1 DESCRIPTION
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SEVERAL DIFFERENT COMPONENTS MAKE UP THIS ALTERNATIVE AND ARE DISCUSSED
IN THIS SECTION. THE GROUNDWATER COLLECTION TECHNIQUE FOR THIS
ALTERNATIVE IS DISCUSSED IN SECTION 7.7.1.
REMEDIATION OF THE 48,200 CUBIC YARDS OF AFFECTED SOIL WOULD BE THROUGH
IN-SITU BIODEGRADATION. THIS PROCESS OPTION, COUPLED WITH GROUNDWATER
COLLECTION, CAN PROVIDE SUBSTANTIAL REDUCTION IN CONCENTRATIONS OF
ORGANIC COMPOUNDS INTO WATER AND CARBON DIOXIDE IN THE PRESENCE OF
SUFFICIENT OXYGEN AND NUTRIENTS AND PHOSPHOROUS.
TYPICAL UNIT PROCESSES THAT WOULD BE REQUIRED FOR THIS ELEMENT FOLLOW:
*
*
BIOLOGICAL INOCULUM FERMENTER
NUTRIENT FEED SYSTEM
*
*
OXYGENATION SYSTEM
CHEMICAL/BIOLOGICAL ADDITIVE CONTROL AND FEED SYSTEM
SITE SPECIFIC PILOT TESTS WOULD BE REQUIRED TO ESTIMATE A TIME OF
COMPLETION FOR REMEDIATION.
TREATMENT OF AFFECTED SLUDGE WHICH CONSISTS OF 23,000 CUBIC YARDS, WOULD
BE PERFORMED ON-SITE WITH ONE OF THE FOLLOWING PROCESSES: THERMAL
DESTRUCTION, THERMAL SEPARATION, GLYCOLATE DECHLORINATION, OR PHYSICAL
STABILIZATION. HOWEVER, IF TREATABILITY DATA SO INDICATES,
BIOREMEDIATION OF SLUDGE MAY BE APPROPRIATE. THE DESCRIPTIONS FOR THE
FIRST FOUR OPTIONS ARE DISCUSSED IN SECTION 7.8.1. THE TREATMENT
RESIDUALS WOULD REMAIN ON-SITE FOR DISPOSAL IN A SECURE TSCA LANDFILL.
THE VOLUME OF THE TREATMENT RESIDUALS WOULD BE DETERMINED DURING THE
TREATABILITY STUDY.
IN THIS ALTERNATIVE, SOLID WASTES WOULD BE EXCAVATED THEN TREATED AND
DISPOSED OF OFF-SITE IN A TSCA LANDFILL. IF THERMAL DESTRUCTION IS THE
OPTION SELECTED FOR SLUDGE TREATMENT, SOLID WASTES WOULD BE TREATED
ON-SITE; OTHERWISE, THE 2,900 CUBIC YARDS OF SOLID WASTES WOULD BE
SHIPPED OFF-SITE FOR THERMAL DESTRUCTION. THIS RESPONSE ACTION IS
DISCUSSED IN SECTION 7.8.1.
7.9.2 EFFECTIVENESS
THE SHORT-TERM PROTECTION PROVIDED DURING EXCAVATION AND TREATMENT OF
ALL SLUDGES AND SOLID WASTES CONTAINING GREATER THAN 25 PPM PCBS WOULD
BE SIMILAR TO THAT DISCUSSED IN SECTION 7.4.2. HOWEVER, IMPLEMENTATION
OF THIS ALTERNATIVE WOULD REQUIRE A GREATER VOLUME OF MATERIAL TO BE
EXCAVATED THAN THAT INCLUDED IN ALTERNATIVE 4. TEMPORARY BERMS AND
RUN-OFF CONTROL DITCHES WOULD BE USED TO CONTROL TRANSPORT OF AFFECTED
SOLIDS AT GROUND SURFACE.
LONG-TERM PROTECTION WOULD BE ACCOMPLISHED BY REMOVAL AND DESTRUCTION OF
SLUDGES AND SOLID WASTES. THE TOXICITY, MOBILITY, AND VOLUME OF THESE
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MEDIA WOULD BE REDUCED BY TREATMENT.
THE LONG-TERM EFFECTIVENESS OF THE GROUNDWATER REMEDIATION SYSTEM IS
UNKNOWN.
THE LONG-TERM EFFECTIVENESS OF BIODEGRADATION IS POOR IN AREAS WHERE
AFFECTED SOILS LIE ABOVE GROUNDWATER. HOWEVER, LIMITED ACTIONS IN THOSE
AREAS WOULD SUPPLEMENT BIOREMEDIATION AND INCREASE THE PROTECTION OF
HUMAN HEALTH AND THE ENVIRONMENT FROM EXPOSURE TO WASTE CONSTITUENTS.
THE EFFECTIVENESS WOULD BE MAINTAINED BY USE OF A PROGRAM INCLUDING
INSTITUTIONAL CONTROLS, SURFACE CARE IN BIOREMEDIATION AREAS, AND
GROUNDWATER MONITORING.
THE ON-SITE LAND DISPOSAL COMPONENT OF THIS ALTERNATIVE WOULD BE
EFFECTIVE IN PROTECTING HUMAN HEALTH AND THE ENVIRONMENT FROM EXPOSURE
TO WASTE CONSTITUENTS IN THE VICINITY OF THE LAND DISPOSAL UNIT. THE
EFFECTIVENESS WOULD BE MAINTAINED BY USE OF A PROGRAM INCLUDING SURFACE
CARE AT THE LANDFILL, GROUNDWATER MONITORING, AND LEACHATE TREATMENT.
7.10 ALTERNATIVE 10:
LIMITED GROUNDWATER ACTION WITH ON-SITE TREATMENT
AND OFF-SITE DISPOSAL OF SOLIDS
7.10.1 DESCRIPTION
THE COMPONENTS OF THIS ALTERNATIVE ARE DISCUSSED AS FOLLOWS:
1.
GROUNDWATER COMPONENT - LIMITED ACTION, SECTION 7.2.1.
2.
EXCAVATION AND TREATMENT OF SOIL, SLUDGE, AND SOLID
WASTES - LIMITED GROUNDWATER ACTION WITH ON-SITE TREATMENT AND
OFF-SITE DISPOSAL OF SOLIDS, SECTION 7.8.1.
THE COMPONENT THAT MAKES THIS ALTERNATIVE DIFFERENT FROM ALTERNATIVE 8
IS OFF-SITE DISPOSAL OF TREATMENT RESIDUALS.
7.10.2 EFFECTIVENESS
THE SHORT-TERM PROTECTION PROVIDED DURING EXCAVATION AND TREATMENT OF
ALL SOLIDS CONTAINING GREATER THAN 25 PPM PCBS WOULD BE PROVIDED BY USE
OF CONSTRUCTION METHODS THAT MINIMIZE TRANSPORT OF AFFECTED MATERIALS.
TEMPORARY BERMS AND RUN-OFF CONTROL DITCHES WOULD BE USED TO CONTROL
TRANSPORT OF AFFECTED SOLIDS AT GROUND SURFACE.
LONG-TERM PROTECTION WOULD BE ACCOMPLISHED BY REMOVAL AND DESTRUCTION OF
WASTE CONSTITUENTS. THE TOXICITY, MOBILITY, AND VOLUME OF AFFECTED
MATERIALS WOULD BE REDUCED BY TREATMENT. ANY POTENTIAL LONG-TERM
MIGRATION AT GROUND SURFACE BY THE LOW CONCENTRATIONS OF WASTE
CONSTITUENTS THAT REMAIN IN PLACE WOULD BE LIMITED BY PLACEMENT OF CLEAN
BACKFILL.
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GROUNDWATER QUALITY WOULD BE MONITORED BY THE SAMPLING AND ANALYSES
PROPOSED AS PART OF THE NO ACTION RESPONSE DESCRIBED IN SECTION 7.1.
THE TREATMENT PROCESSES UNDER CONSIDERATION AS PART OF THIS ALTERNATIVE
HAVE BEEN SHOWN TO BE EFFECTIVE IN REDUCING AT LEAST ONE OF THREE WASTE
CHARACTERISTICS: TOXICITY, MOBILITY OR VOLUME FOR ONE OR MORE OF THE
CONSTITUENTS OF CONCERN. THESE TREATMENT PROCESSES ARE DISCUSSED IN
ALTERNATIVE 8. THE COMBINATION OF TREATMENT WITH DISPOSAL OF RESIDUALS
IN AN OFF-SITE SECURE TSCA LANDFILL WOULD PROVIDE AN EFFECTIVE MEANS OF
REDUCING TOXICITY, MOBILITY, AND VOLUME OF WASTE CONSTITUENTS.
7.11 ALTERNATIVE 11: TREATMENT OF GROUNDWATER WITH ON-SITE TREATMENT AND
ON-SITE DISPOSAL OF SOLIDS
7.11.1 DESCRIPTION
THE COMPONENTS THAT MAKE UP THIS ALTERNATIVE ARE IDENTICAL TO THOSE OF
ALTERNATIVE 8 WITH ONE EXCEPTION: IN THIS ALTERNATIVE, GROUNDWATER WOULD
BE REMEDIATED BY COLLECTION, TREATMENT AND DISPOSAL. THIS ACTION FOR
GROUNDWATER IS DESCRIBED IN SECTION 7.7.1.
7.11.2 EFFECTIVENESS
THE SHORT-TERM PROTECTION PROVIDED DURING EXCAVATION AND TREATMENT OF
ALL SOLIDS CONTAINING GREATER THAN 25 PPM PCBS WOULD BE ACCOMPLISHED BY
USE OF CONSTRUCTION METHODS THAT MINIMIZE TRANSPORT OF AFFECTED
MATERIALS. THE LARGE VOLUME OF MATERIAL TO BE MOVED DURING EXCAVATION
WOULD RESULT IN A PERIOD DURING WHICH A POTENTIAL FOR EXPOSURE WOULD
EXIST. TEMPORARY BERMS AND RUN-OFF CONTROL DITCHES WOULD BE USED TO
CONTROL TRANSPORT OF AFFECTED SOLIDS AT GROUND SURFACE.
LONG-TERM PROTECTION WOULD BE ACCOMPLISHED BY REMOVAL AND DESTRUCTION OF
WASTE CONSTITUENTS. THE TOXICITY, MOBILITY, AND VOLUME OF HAZARDOUS
MATERIALS WOULD BE REDUCED BY TREATMENT.
ANY POTENTIAL LONG-TERM MIGRATION AT GROUND SURFACE BY THE LOW
CONCENTRATIONS OF WASTE CONSTITUENTS THAT REMAIN IN PLACE WOULD BE
LIMITED BY PLACEMENT OF CLEAN BACKFILL.
THE TREATMENT PROCESSES UNDER CONSIDERATION AS PART OF THIS ALTERNATIVE
INCLUDING INCINERATION, THERMAL SEPARATION, GLYCOLATE DECHLORINATION,
AND STABILIZATION/FIXATION, HAVE BEEN SHOWN TO BE EFFECTIVE IN REDUCTION
OF AT LEAST ONE OF THREE WASTE CHARACTERISTICS: TOXICITY, MOBILITY, OR
VOLUME FOR ONE OR MORE OF THE CONSTITUENTS OF CONCERN. THESE TREATMENT
PROCESSES ARE DISCUSSED IN ALTERNATIVE 8. THE COMBINATION OF TREATMENT
WITH DISPOSAL OF RESIDUALS IN AN ON-SITE SECURE LANDFILL WOULD PROVIDE
AN EFFECTIVE MEANS OF REDUCING TOXICITY, MOBILITY, AND VOLUME OF WASTE
CONSTITUENTS.
THE ON-SITE LAND DISPOSAL COMPONENT OF THIS ALTERNATIVE WOULD BE
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EFFECTIVE IN PROTECTING HUMAN HEALTH AND THE ENVIRONMENT FROM EXPOSURE
TO WASTE CONSTITUENTS IN THE VICINITY OF THE LAND DISPOSAL UNIT. THE
EFFECTIVENESS WOULD BE MAINTAINED BY USE OF A PROGRAM INCLUDING SURFACE
CARE AT THE LANDFILL, GROUNDWATER MONITORING, AND LEACHATE TREATMENT.
7.12 ALTERNATIVE 12: TREATMENT OF GROUNDWATER WITH ON-SITE
AND OFF-SITE DISPOSAL OF SOLIDS
TREATMENT
7.12.1 DESCRIPTION
THE COMPONENTS THAT COMPRISE THIS ALTERNATIVE ARE THE SAME AS THOSE THAT
MAKE UP ALTERNATIVE 10, WITH ONE EXCEPTION: THIS ALTERNATIVE INCLUDES
COLLECTION, TREATMENT, AND DISCHARGE OF GROUNDWATER. THE ELEMENTS THAT
WOULD BE USED TO EXCAVATE AND TREAT SOLID MATERIALS ARE DESCRIBED IN
SECTION 7.8.1. THE ELEMENTS THAT WOULD BE USED TO TRANSPORT AND DISPOSE
THE MATERIALS ARE DESCRIBED IN SECTION 7.6.1.
7.12.2 EFFECTIVENESS
THE SHORT-TERM PROTECTION PROVIDED DURING EXCAVATION AND TREATMENT OF
ALL SOLIDS CONTAINING GREATER THAN 25 PPM PCBS WOULD BE ACCOMPLISHED BY
USE OF CONSTRUCTION METHODS THAT MINIMIZE TRANSPORT OF AFFECTED
MATERIALS. EXCAVATION OF ALL SOLIDS WOULD RESULT IN A PERIOD DURING
WHICH THE RISK OF EXPOSURE WOULD BE INCREASED. TEMPORARY BERMS AND
RUN-OFF CONTROL DITCHES WOULD BE USED TO CONTROL TRANSPORT OF AFFECTED
SOLIDS AT THE GROUND SURFACE. ANY WASTES HAULED OFF-SITE COULD
POTENTIALLY EXPOSE THOSE PERSONS USING THE SAME ROADS, OR LIVING OR
WORKING ALONG THE ROUTE, TO AFFECTED TREATMENT RESIDUALS.
LONG-TERM PROTECTION WOULD BE ACCOMPLISHED BY REMOVAL AND DESTRUCTION OF
WASTE CONSTITUENTS. THE TOXICITY, MOBILITY, AND VOLUME OF WASTE
MATERIALS WOULD BE REDUCED BY TREATMENT. ANY POTENTIAL LONG-TERM
MIGRATION AT GROUND SURFACE BY THE LOW CONCENTRATIONS OF WASTE
CONSTITUENTS THAT REMAIN IN PLACE WOULD BE LIMITED BY PLACEMENT OF CLEAN
BACKFILL AND MONITORED BY THE SAMPLING AND ANALYSES PROPOSED AS PART OF
THE LIMITED ACTION PLAN FOR SOLIDS.
THE TREATMENT PROCESSES UNDER CONSIDERATION AS PART OF THIS ALTERNATIVE,
INCLUDING ROTARY KILN INCINERATION, THERMAL SEPARATION, GLYCOLATE
DECHLORINATION, AND STABILIZATION/FIXATION HAVE BEEN SHOWN TO BE
EFFECTIVE IN REDUCTION OF AT LEAST ONE OF THREE WASTE CHARACTERISTICS:
TOXICITY, MOBILITY OR VOLUME FOR ONE OR MORE OF THE CONSTITUENTS OF
CONCERN. THESE TREATMENT PROCESSES ARE DISCUSSED IN ALTERNATIVE 8. THE
COMBINATION OF TREATMENT WITH DISPOSAL OF RESIDUALS IN AN OFF-SITE
SECURE LANDFILL WOULD PROVIDE AN EFFECTIVE MEANS OF REDUCING TOXICITY,
MOBILITY, AND VOLUME OF WASTE CONSTITUENTS.
ALTERNATIVE 13:
CONSOLIDATED REMEDY/NO ACTION, LIMITED ACTION.
EXCAVATION AND TREATMENT OF ACTIVE AND INACTIVE
LAGOON SLUDGES
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7.13.1 DESCRIPTION
THIS ALTERNATIVE INCLUDES REMEDIAL ACTION ELEMENTS PREVIOUSLY DISCUSSED
IN THE DESCRIPTIONS OF OTHER ALTERNATIVES AND ADDRESSES EACH SECTION OF
THE PLANT AND OFF-SITE AREAS WITH RESPECT TO THE SPECIFIC REMEDIAL
REQUIREMENTS OF EACH LOCATION. WHILE A LARGER NUMBER OF TECHNOLOGY
COMBINATIONS ARE POSSIBLE, THIS ALTERNATIVE OPTIMIZES THE USE OF
MULTIPLE REMEDIAL ACTIONS WITHIN ONE CONSOLIDATED REMEDY.
PLANT SITE:
NO ACTION ON ALL MEDIA: DRAINFIELD (200 CUBIC YARDS OF SOIL).
LIMITED ACTION ON GROUNDWATER WITH CONTAINMENT OF SOLIDS:
PLANT AREAS A, B, C, E, F, G/H (15,500 CUBIC YARDS OF SOLID WASTE)
LIMITED ACTION ON GROUNDWATER WITH SLUDGE EXCAVATION (18,400 CUBIC
YARDS), TREATMENT, AND ON-SITE DISPOSAL OF RESIDUALS:
WASTEWATER TREATMENT PLANT - STABILIZATION LAGOON (VOLUME OF TREATMENT
RESIDUALS WOULD BE DETERMINED DURING THE TREATABILITY STUDY).
LIMITED ACTION ON GROUNDWATER WITH CONTAINMENT OF AFFECTED SOILS (9,700
CUBIC YARDS), AND SLUDGE EXCAVATION (3,800 CUBIC YARDS), TREATMENT, AND
ON-SITE DISPOSAL OF WASTE:
WASTEWATER TREATMENT PLANT - INACTIVE LAGOON.
OFF-SITE AREAS
NO ACTION ON ALL MEDIA:
NIX AND WELBORN (1200 CUBIC YARDS OF SOLIDS).
LIMITED ACTION ON GROUNDWATER AND SOLIDS:
CROSSROADS (5,100 CUBIC YARDS OF SOLIDS).
LIMITED ACTION ON GROUNDWATER WITH CONTAINMENT OF SOLIDS:
BREAZEALE (5,500 CUBIC YARDS OF SOLIDS).
NO ACTION ON GROUNDWATER WITH CONTAINMENT OF SOLIDS:
DODGENS (2,000 CUBIC YARDS), AND JOHN TROTTER (700 CUBIC YARDS OF
SOLIDS).
THE TECHNICAL COMPONENTS OF ALL THESE ELEMENTS WERE DISCUSSED IN THE
DESCRIPTION SECTION OF PREVIOUSLY ANALYZED ALTERNATIVES.
7.13.2 EFFECTIVENESS
IN AREAS WHERE EITHER NO ACTION OR LIMITED ACTION ARE PROPOSED, THIS
ALTERNATIVE WOULD NOT CHANGE THE CHARACTERISTICS OF THE WASTE AND
AFFECTED MATERIAL. THEREFORE, TOXICITY, MOBILITY, AND VOLUME OF THE
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MATERIAL WOULD BE REDUCED ONLY TO THE DEGREE PROVIDED BY NATURAL
ATTENUATION. LAND USE RESTRICTIONS INSTITUTED AS PART OF LIMITED ACTION
WOULD MITIGATE THE POTENTIAL RISK POSED BY DIRECT CONTACT WITH AFFECTED
MATERIAL LEFT IN PLACE.
WHERE CONTAINMENT IS IMPLEMENTED, THE SHORT-TERM EFFECTIVENESS WOULD BE
IMPROVED OVER THAT PROVIDED BY EXCAVATION. THE AFFECTED MATERIAL WOULD
BE CAPPED WITH A RELATIVELY SMALL INCREASE IN INHALATION EXPOSURES BY
WORKERS AND OFF-SITE POPULATIONS.
IN AREA D AT THE PLANT SITE, THE SHORT-TERM EXPOSURES FROM INSTALLING
A VACUUM EXTRACTION SYSTEM WOULD BE NO GREATER THAN THAT ASSOCIATED WITH
INSTALLATION OF GROUNDWATER MONITORING WELLS. THE LONG-TERM EFFECTS OF
VACUUM EXTRACTION OF VOLATILE ORGANICS WOULD BE DECREASES IN MOBILITY OF
WASTE CONSTITUENTS AND REDUCTION IN THE TOXICITY AND VOLUME OF THOSE
CONSTITUENTS IN THE SOIL PORE SPACE.
EXCAVATION, TREATMENT, AND ON-SITE DISPOSAL OF SLUDGE RESIDUALS WOULD
CAUSE AN INCREASE IN THE EXPOSURE POTENTIAL OF WASTE CONSTITUENTS DURING
CONSTRUCTION. THE LONG-TERM EFFECTS WOULD BE A DECREASE IN THE TOXICITY
AND MOBILITY OF AFFECTED MATERIALS.
#SCAA
8.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
GROUNDWATER ALTERNATIVES
ALTERNATIVES 7, 9, 11 AND 12 INCLUDE EXTRACTION AND TREATMENT OF
CONTAMINATED GROUNDWATER AT THE PLANT SITE, DODGENS, BREAZEALE, AND
CROSS ROADS SITES. THESE ALTERNATIVES WOULD PREVENT FURTHER MIGRATION
OF THE CONTAMINANT PLUME AND WOULD, THEREFORE PROVIDE THE BEST OVERALL
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT. THE REMAINING SITES DID
NOT APPEAR TO HAVE CONTAMINATION AT LEVELS ABOVE ACCEPTABLE LIMITS.
INSTITUTIONAL CONTROLS (I.E. DEED RESTRICTIONS, ORDINANCES BANNING
SHALLOW WELLS, FENCES, ETC.) WOULD PROVIDE LIMITED PROTECTION, BUT WOULD
NOT PREVENT EVENTUAL CONTAMINATION OF SURFACE WATER AND FURTHER
CONTAMINATION OF GROUNDWATER. THE NO ACTION ALTERNATIVE WOULD NOT
PROVIDE ANY PROTECTION FOR HUMAN HEALTH OR THE ENVIRONMENT.
SOURCE CONTROL ALTERNATIVES
ALTERNATIVES 8, 10, 11, AND 12 INCLUDED FOUR TECHNOLOGIES FOR TREATMENT
OF CONTAMINATED WASTE AND SOIL WERE EVALUATED IN THE FEASIBILITY STUDY.
THESE WERE INCINERATION, LOW-TEMPERATURE THERMAL SEPARATION, GLYCOLATE
DECHLORINATION AND SOLIDIFICATION. OF THESE TREATMENTS, THERMAL
SEPARATION ON OR OFF-SITE APPEARS TO PROVIDE THE BEST OVERALL PROTECTION
OF HUMAN HEALTH AND THE ENVIRONMENT. THERMAL SEPARATION USES AN
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INDIRECT HEAT SOURCE TO REMOVE CONTAMINATION FROM THE SOIL, THEREBY
CONDENSING IT INTO A MORE MANAGEABLE VOLUME. INCINERATION WOULD ALSO
PROVIDE PROTECTION FOR HUMAN HEALTH AND THE ENVIRONMENT. GLYCOLATE
DECHLORINATION HAS NOT BEEN DEMONSTRATED TO BE EFFECTIVE IN THE FIELD
AND IT IS UNCERTAIN HOW PROTECTIVE THIS TREATMENT WOULD BE.
SOLIDIFICATION OF THE MATERIALS WOULD BE INEFFECTIVE DUE TO THE PRESENCE
OF OILS AND OTHER WASTES THAT WOULD INTERFERE WITH EFFECTIVE
SOLIDIFICATION OF THE MATERIALS. OTHER ALTERNATIVES EVALUATED
CONTAINMENT OR OFF-SITE DISPOSAL OF CONTAMINATED MATERIALS. IT IS
UNLIKELY THESE WOULD PROVIDE ADEQUATE PROTECTION OF HUMAN HEALTH AND THE
ENVIRONMENT OVER THE LONG TERM. CAPS DEGRADE AND LANDFILLS ARE SUBJECT
TO DEGRADATION-AND/OR LEACHATE PRODUCTION THAT COULD CREATE NEW
PROBLEMS.
COMPLIANCE WITH ARARS
ARARS FOR TREATING OR MANAGING PCB-CONTAMINATED MATERIAL DERIVE
PRIMARILY FROM TWO SETS OF REGULATIONS: THE TOXIC SUBSTANCES CONTROL ACT
(TSCA) PCB REGULATIONS AND THE RESOURCE CONSERVATION AND RECOVERY ACT
(RCRA) LAND DISPOSAL RESTRICTIONS (LDRS). WHERE PCBS AFFECT GROUND OR
SURFACE WATER, THE SAFE DRINKING WATER ACT (SDWA) AND CLEAN WATER ACT
(CWA) PROVIDE POTENTIAL ARARS FOR ESTABLISHING REMEDIATION GOALS; I.E.,
MAXIMUM CONTAMINANT LEVELS (MCLS), MAXIMUM CONTAMINANT LEVEL GOALS
(MCLGS), AND WATER QUALITY CRITERIA (WQC). IN ADDITION, THE PCB SPILL
POLICY, WHICH IS NOT AN ARAR, ALTHOUGH IT IS PUBLISHED IN THE CODE OF
FEDERAL REGULATIONS, HAS BEEN CONSIDERED IN DETERMINING CLEANUP LEVELS
AT THE SITE. THE TSCA PCB REGULATIONS OF IMPORTANCE TO SUPERFUND
ACTIONS ARE FOUND IN 40 CFR SECTION 761.60 - 761.79, SUBPART D: STORAGE
AND DISPOSAL. THEY SPECIFY TREATMENT, STORAGE, AND DISPOSAL
REQUIREMENTS FOR PCBS BASED ON THEIR FORM AND CONCENTRATION.
TSCA REQUIREMENTS DO NOT APPLY TO PCBS AT CONCENTRATIONS LESS THAN 50
PPM; HOWEVER, PCBS CANNOT BE DILUTED TO ESCAPE TSCA REQUIREMENTS.
CONSEQUENTLY, UNDER TSCA, PCBS THAT HAVE BEEN DEPOSITED IN THE
ENVIRONMENT AFTER THE EFFECTIVE DATE OF THE REGULATION, FEBRUARY 17,
1978, ARE TREATED, FOR THE PURPOSES OF DETERMINING DISPOSAL
REQUIREMENTS, AS IF THEY WERE AT THE CONCENTRATION OF THE ORIGINAL
MATERIAL. FOR EXAMPLE, IF PCB TRANSFORMERS LEAKED OIL CONTAINING PCBS
AT GREATER THAN 500 PPM, THE SOIL CONTAMINATED BY THE OIL WOULD HAVE TO
BE EXCAVATED AND DISPOSED OF AS IF ALL OF THE PCB-CONTAMINATED SOIL
CONTAINED PCBS AT GREATER THAN 500 PPM. THIS REFLECTS AN INTERPRETATION
OF THE ANTI-DILUTION PROVISIONS IN TSCA (40 CFR 761.1(B)). EPA HAS
CLARIFIED THAT TSCA ANTI-DILUTION PROVISIONS ARE ONLY APPLICABLE TO
CERCLA RESPONSE ACTIONS THAT OCCUR ONCE A REMEDIAL ACTION IS INITIATED.
THE DETERMINATION OF WHETHER CONTAMINATED MATERIAL SHOULD BE CONSIDERED
A SOIL OR AN INDUSTRIAL SLUDGE WILL BE MADE SITE SPECIFICALLY DURING
REMEDIAL DESIGN CONSISTENT WITH THE CURRENT PROCESS FOR CLASSIFYING
MATERIAL SUBJECT TO THE LAND DISPOSAL RESTRICTIONS AS EITHER A PURE
WASTE OR A SOIL AND DEBRIS CONTAMINATED WITH A WASTE.
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THE REQUIREMENTS FOR STORAGE OF PCBS ARE DESCRIBED IN 40 CFR SECTION
761.65. THE REGULATIONS SPECIFY THAT PCBS AT CONCENTRATIONS OF 50 PPM
OR GREATER MUST BE DISPOSED OF WITHIN ONE YEAR AFTER BEING PLACED IN
STORAGE. THE REGULATIONS ALSO INCLUDE STRUCTURAL REQUIREMENTS FOR
FACILITIES USED FOR THE STORAGE OF PCBS AND REQUIREMENTS FOR CONTAINERS
USED TO STORE PCBS.
PCBS ARE SPECIFICALLY ADDRESSED UNDER RCRA IN 40 CFR 268 WHICH DESCRIBES
THE PROHIBITIONS ON LAND DISPOSAL OF VARIOUS HAZARDOUS WASTES. NOTE
THAT RCRA REGULATIONS ONLY APPLY TO WASTE THAT IS CONSIDERED HAZARDOUS
UNDER RCRA; I.E., LISTED IN 40 CFR 261.3 OR CHARACTERISTIC AS DESCRIBED
IN 40 CFR 261.2. PCBS ALONE ARE NOT A RCRA HAZARDOUS WASTE; HOWEVER, IF
THE PCBS ARE MIXED WITH A RCRA HAZARDOUS WASTE, THEY MAY BE SUBJECT TO
LAND DISPOSAL RESTRICTIONS.
PCBS ARE ONE OF THE CONSTITUENTS ADDRESSED BY THE LAND DISPOSAL
RESTRICTIONS UNDER THE CALIFORNIA LIST WASTES. THIS SUBSECTION OF
WASTES COVERS LIQUID HAZARDOUS WASTES CONTAINING PCBS AT CONCENTRATIONS
GREATER THAN OR EQUAL TO 50 PPM AND NON-LIQUID HAZARDOUS WASTES
CONTAINING TOTAL CONCENTRATIONS OF HALOGENATED ORGANIC COMPOUNDS (HOCS)
AT CONCENTRATIONS GREATER THAN 1000 PPM. PCBS ARE INCLUDED IN THE LIST
OF HOCS PROVIDED IN THE REGULATION (APPENDIX III PART 268).
AS DESCRIBED IN 40 CFR 268.42(A)(1), LIQUID HAZARDOUS (RCRA LISTED OR
CHARACTERISTIC) WASTES CONTAINING PCBS AT CONCENTRATIONS GREATER THAN OR
EQUAL TO 500 PPM MUST BE INCINERATED IN A FACILITY MEETING THE
REQUIREMENTS OF 40 CFR 761.70. LIQUID HAZARDOUS WASTES CONTAINING PCBS
AT CONCENTRATIONS GREATER THAN OR EQUAL TO 50 PPM, BUT LESS THAN 500 PPM
MUST BE INCINERATED OR BURNED IN A HIGH EFFICIENCY BOILER MEETING THE
REQUIREMENTS OF 40 CFR 761.60. A METHOD OF TREATMENT EQUIVALENT TO THE
REQUIRED TREATMENT MAY ALSO BE USED UNDER A TREATABILITY VARIANCE
PROCEDURE IF THE ALTERNATE TREATMENT CAN ACHIEVE A LEVEL OF PERFORMANCE
EQUIVALENT TO THAT ACHIEVED BY THE SPECIFIED METHOD AS DESCRIBED IN 40
CFR 268.42(B).
LIQUID AND NON-LIQUID HAZARDOUS WASTES CONTAINING HOCS IN TOTAL
CONCENTRATION GREATER THAN OR EQUAL TO 1000 PPM MUST BE INCINERATED IN
ACCORDANCE WITH THE REQUIREMENT OF 40 CFR 264 SUBPART O. AGAIN, A
METHOD OF TREATMENT EQUIVALENT TO THE REQUIRED TREATMENT, UNDER A
TREATABILITY VARIANCE, MAY ALSO BE USED.
ALL EXTRACTED AND TREATED WATER WOULD HAVE TO MEET NPDES REQUIREMENTS
PRIOR TO SURFACE WATER DISCHARGE. A DETERMINATION OF THE LOCATION OF
THE DISCHARGES, WHICH IS EXPECTED TO BE MADE DURING DESIGN, IS NECESSARY
BEFORE AN IDENTIFICATION OF WHETHER THE DISCHARGES ARE OFF-SITE VS
ON-SITE AS DEFINED IN THE NCP (40 CFR PART 300.400(E)).
GROUNDWATER CLEAN-UP GOALS ARE ESTABLISHED AS MCLS, PROPOSED MCLS
(PMCLS) AND CANCER POTENCY FACTORS (CPFS) AND ARE PRESENTED IN TABLE 6-6
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FOR THE COMPOUNDS IDENTIFIED IN GROUNDWATER. AS DISCUSSED IN SECTION
9.1, A WAIVER MAY EVENTUALLY BE NECESSARY FOR THE GROUNDWATER AS IT IS
UNLIKELY MCLS WILL BE MET. THIS IS DUE TO THE PRESENCE OF DENSE
NON-AQUEOUS PHASE LIQUIDS IN THE FRACTURE SYSTEM PRESENT AT THE VARIOUS
SITES. ALL SOURCE TREATMENT ALTERNATIVES ARE EXPECTED TO MEET ARARS.
WHERE EXCAVATION IS REQUIRED, THE REQUIREMENTS OF THE CLEAN AIR ACT
UNDER 40 CFR PART 50 CONCERNING PARTICULATES AND VOLATILE ORGANIC
EMISSIONS WILL BE REQUIRED TO BE MET.
LONG-TERM EFFECTIVENESS AND PERMANENCE
GROUND WATER TREATMENT AND DISCHARGE
EXTRACTION OF CONTAMINATED GROUNDWATER WILL BE EFFECTIVE IN CONTAINING
THE PLUME OVER THE LONG-TERM. IT IS UNLIKELY THAT THE SOURCE OF THE
PLUME CAN BE REMOVED IN THIS MANNER. THEREFORE, THE EXTRACTION IS NOT A
PERMANENT REMEDY, ALTHOUGH IT DOES ACCOMPLISH THE GOAL OF PREVENTING
FURTHER CONTAMINATION OF THE AQUIFER.
SOURCE TREATMENT
THERMAL SEPARATION AND INCINERATION PROVIDE FOR REMOVAL AND DESTRUCTION
OF THE CONTAMINANTS FROM THE WASTE AND SOIL. THESE ARE PERMANENT
TREATMENT ALTERNATIVES. OFF-SITE DISPOSAL OF WASTES PROVIDES
LONG-TERM EFFECTIVENESS IN ISOLATING WASTES, BUT CONTAINMENT STRUCTURES
MAY BE SUBJECT TO FAILURE, SO THAT THIS ALTERNATIVE IS LESS PERMANENT
THAN A THERMAL TREATMENT PROCESS. THE POSSIBLE FAILURE OF CONTAINMENT
STRUCTURES IS APPLICABLE TO ON-SITE CONTAINMENT FACILITIES AS WELL. IT
IS UNKNOWN AS TO THE LONG-TERM EFFECTIVENESS AND PERMANENCE OF
BIOREMEDIATION. TO DATE, NO STUDIES ACHIEVING CLEAN-UP CRITERIA HAVE
BEEN REPORTED.
REDUCTION OF MOBILITY, TOXICITY, OR VOLUME
GROUNDWATER TREATMENT
EXTRACTION OF CONTAMINATED GROUNDWATER WILL REDUCE THE VOLUME OF
CONTAMINANTS IN THE AQUIFER AS WELL AS REDUCE THE MOBILITY OF THOSE
CONTAMINANTS REMOVED THROUGH TREATMENT OF THE EXTRACTED WATER. THE NO
ACTION ALTERNATIVE OR USE OF INSTITUTIONAL CONTROLS WILL HAVE NO IMPACT
ON THE MOBILITY, TOXICITY, OR VOLUME OF CONTAMINATION PRESENT AT THE
SITE.
SOURCE TREATMENT
THERMAL SEPARATION REMOVES THE CONTAMINANTS SO THEY CAN BE DESTROYED IN
A MORE CONDENSED, MANAGEABLE STATE. THEREFORE, THERMAL SEPARATION
REDUCES THE MOBILITY, TOXICITY AND VOLUME OF THE CONTAMINANTS PRESENT IN
THE SOLIDS AT THE SITE. INCINERATION DESTROYS THE CONTAMINANTS, THEREBY
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ELIMINATING TOXICITY AND MOBILITY, AND REDUCING VOLUME. CONTAINMENT OF
WASTES REDUCES THE MOBILITY OF THE CONTAMINANTS, HOWEVER, CONTAINMENT
STRUCTURES MAY BE SUBJECT TO FAILURE. GLYCOLATE DECHLORINATION WOULD
REDUCE THE TOXICITY OF CONTAMINANTS. SOLIDIFICATION WOULD REDUCE THE
MOBILITY OF THE CONTAMINANTS. BIOREMEDIATION MAY REDUCE THE TOXICITY OF
CONTAMINANTS OVER THE LONG-TERM. OFF-SITE DISPOSAL OF WASTES DOES NOT
AFFECT THE INHERENT TOXICITY, MOBILITY, OR VOLUME OF THE WASTE.
SHORT-TERM EFFECTIVENESS
GROUND WATER TREATMENT
AIR STRIPPING MAY HAVE THE FOLLOWING SHORT-TERM EFFECTS:
RISKS TO WORKERS FROM EXPOSURE TO DRILLING FLUIDS AND SOIL DURING THE
INSTALLATION OF THE GROUND WATER EXTRACTION WELLS.
RISKS TO WORKERS AND ENVIRONMENT FROM RELEASE OF CONTAMINATED WATER
BECAUSE OF ACCIDENTAL SPILLAGE.
RISKS TO WORKERS, ENVIRONMENT AND NEARBY MEMBERS OF THE PUBLIC FROM
UNCONTROLLED EMISSIONS.
THE REMEDIAL DESIGN WILL INCLUDE ALL NECESSARY MEASURES TO MINIMIZE
POTENTIAL ADVERSE SHORT-TERM EFFECTS ON PUBLIC HEALTH OR THE
ENVIRONMENT.
INSTITUTIONAL CONTROLS WOULD BE EFFECTIVE IN THE SHORT TERM. THEY WOULD
PREVENT THE PUBLIC FROM COMING INTO CONTACT WITH CONTAMINATION OR
CONTAMINATED MATERIAL IN THE SHORT TERM.
SOURCE TREATMENT
ALL ALTERNATIVES REQUIRING EXCAVATION OF CONTAMINATED MATERIALS HAVE
SHORT-TERM IMPACTS ON THE ENVIRONMENT DUE TO THE RELEASE OF VOLATILE
CONTAMINANTS INTO THE AIR.
OFF-SITE DISPOSAL OF CONTAMINATED SOILS OR OFF-SITE INCINERATION OF
THESE WASTES INVOLVE TRANSPORTATION OF THE WASTE, INCREASING SHORT-TERM
RISK TO POPULATIONS ALONG THE TRANSPORT ROUTE. CONSOLIDATION OF
MATERIALS ON THE PLANT SITE ALSO INVOLVES A SHORT-TERM RISK TO
POPULATIONS ALONG THE TRANSPORT ROUTE TO THE PLANT SITE. THESE RISKS
CAN BE MINIMIZED BY UTILIZING AN EXPERIENCED CONTRACTOR FOR THESE TASKS.
IMPLEMENTABILITY
GROUND WATER TREATMENT
AIR STRIPPING AND CARBON ADSORPTION ARE BOTH PROVEN TECHNOLOGIES.
TREATMENT SYSTEMS AND VENDORS ARE READILY AVAILABLE AND NO IMPEDIMENT TO
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IMPLEMENTATION OF THE ALTERNATIVE IS FORESEEN.
SOURCE TREATMENT
THERMAL SEPARATION AND ON-SITE INCINERATION ARE FULLY IMPLEMENTABLE.
OFF-SITE DISPOSAL OF THE CONTAMINATED SOIL IS IMPLEMENTABLE, AS IS
SOLIDIFICATION. EXCAVATION AND OFF-SITE INCINERATION MAY BE DIFFICULT
DUE TO AVAILABILITY OF INCINERATOR CAPACITY IN SOUTH CAROLINA.
GLYCOLATE DECHLORINATION IS A RELATIVELY NEW TECHNOLOGY AND WOULD,
THEREFORE, BE DIFFICULT TO IMPLEMENT AT THE SITE. CONSTRUCTION OF A
TSCA LANDFILL WOULD NOT BE POSSIBLE DUE TO SOUTH CAROLINA DEPARTMENT OF
HEALTH AND ENVIRONMENTAL CONTROL RESTRICTIONS ON PERMITTING SUCH
FACILITIES.
COST-EFFECTIVENESS
ESTIMATED COSTS FOR EACH ALTERNATIVE ARE AS FOLLOWS:
ALTERNATIVE
MILLIONS OF DOLLARS
NO ACTION
ALTERNATIVE 1
$ 5.1
ALTERNATIVES INVOLVING LITTLE OR NO TREATMENT
ALTERNATIVE
ALTERNATIVE
ALTERNATIVE
ALTERNATIVE
ALTERNATIVE
2
3
4
5
6
$ 5.3
$ 7.9 - 8.6
$10.3 - 11.0
$12.7
$57.0
ALTERNATIVES THAT MINIMIZE THE NEED FOR LONG-TERM MANAGEMENT
ALTERNATIVE 8
ALTERNATIVE 10
$14.4 - 57
$27.1
ALTERNATIVE THAT INCLUDES TREATMENT AND REQUIRES LONG-TERM
MANAGEMENT
ALTERNATIVE 13
$11.2 - 15.1
ALTERNATIVES THAT MINIMIZE THE NEED FOR LONG-TERM TREATMENT
ALTERNATIVE 7
$29.4
ALTERNATIVE 11
$34.5 - 78.4
ALTERNATIVE 12
$62.4 - 99.2
ALTERNATIVES THAT REQUIRES LONG-TERM MANAGEMENT
ALTERNATIVE 9
$39.6 - 50.6
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STATE ACCEPTANCE
THE STATE OF SOUTH CAROLINA HAS CONCURRED WITH THE SELECTED REMEDY.
COMMUNITY ACCEPTANCE
TWO PUBLIC MEETINGS WERE HELD DURING THE PUBLIC COMMENT PERIOD AT THE
SITE. CITIZENS VOICED SOME CONCERNS OVER THE SELECTED REMEDY BUT
APPEARED TO BE SATISFIED BY THE AGENCY'S RESPONSES. WRITTEN COMMENTS
RECEIVED DURING THE PUBLIC COMMENT PERIOD WERE IN THE FORM OF REQUESTS
FOR MORE INFORMATION. ONE COMMENT RECOMMENDED EPA CONSTRUCT A TSCA
LANDFILL AT A "SAFE" SITE IN THE COUNTY. THE COMMENTS WERE ADDRESSED IN
THE RESPONSIVENESS SUMMARY.
#SR
9.0 THE SELECTED REMEDY
THE REMEDY SELECTED FOR OPERABLE UNIT ONE OF THE SANGAMO WESTON/TWELVE
MILE CREEK/LAKE HARTWELL PCB CONTAMINATION SITE IS:
EXTRACTION AND TREATMENT BY AIR STRIPPING AND/OR CARBON ADSORPTION OF
CONTAMINATED GROUNDWATER AT THE DODGENS, BREAZEALE, CROSS ROADS AND
PLANT SITES;
DISCHARGE OF TREATED WATER TO THE NEAREST VIABLE SURFACE WATER BODY IN
ACCORDANCE WITH APPLICABLE REGULATIONS;
EXCAVATION OF MATERIALS CONTAMINATED WITH GREATER THAN 1 PPM OF PCBS AT
THE NIX AND WELBORN PROPERTIES AND TRANSPORT OF THE MATERIALS TO THE
SANGAMO PLANT SITE FOR STAGING AND APPROPRIATE TREATMENT
EXCAVATION OF MATERIALS CONTAMINATED WITH GREATER THAN 10 PPM PCBS ON
THE REMAINING FOUR PRIVATE PROPERTIES (TROTTER, DODGENS, BREAZEALE AND
CROSS ROADS) AND TRANSPORT TO THE SANGAMO PLANT SITE FOR STAGING AND
APPROPRIATE TREATMENT;
BACKFILL TWO FEET OF CLEAN FILL AT EACH OF THE PRIVATE PROPERTIES WHERE
CONTAMINATED MATERIALS OF GREATER THAN 1 PPM REMAIN (TROTTER, DODGENS,
BREAZEALE AND CROSS ROADS);
EXCAVATE MATERIAL CONTAINING GREATER THAN 25 PPM CONCENTRATION OF PCBS
ON THE PLANT SITE;
TREAT ALL EXCAVATED MATERIALS TO 2 PPM PCBS USING THERMAL SEPARATION
TECHNOLOGY ON THE PLANT SITE. DURING REMEDIAL DESIGN, A TREATABILITY
STUDY WILL BE CONDUCTED TO DETERMINE IF ANY OF THE CONTAMINATED
MATERIALS WILL REQUIRE ADDITIONAL TREATMENT BEYOND THERMAL SEPARATION IN
ORDER TO MEET THE 2 PPM CRITERIA. IF NECESSARY, A ROD AMENDMENT WILL BE
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Order number 940620-103843-ROD
-001-001
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COMPLETED TO ACCOUNT FOR THIS REQUIRED TREATMENT; AND
REPLACE REMEDIATED SOIL ON THE PLANT SITE
THIS REMEDY WILL ATTAIN A (10-6) CANCER RISK LEVEL AS IT REMOVES THE
SOURCE OF THE DIRECT CONTACT THREAT AND CONTAINS THE CONTAMINATED
GROUNDWATER TO PREVENT FUTURE CONTACT.
9.1 DESCRIPTION OF RECOMMENDED ALTERNATIVE GROUNDWATER TREATMENT
THE ULTIMATE GOAL OF THIS REMEDIAL ACTION IS TO RESTORE THE GROUNDWATER
TO ITS BENEFICIAL USE, WHICH AT THIS SITE IS A DRINKING WATER AQUIFER
(SEE TABLE 6.6 FOR GROUNDWATER CLEAN UP CRITERIA). BASED ON THE
INFORMATION OBTAINED DURING THE REMEDIAL INVESTIGATION, AND THE ANALYSIS
OF ALL REMEDIAL ALTERNATIVES, EPA BELIEVES THAT IT MAY BE POSSIBLE TO
ACHIEVE THIS GOAL FOR SELECT AREAS USING THE PLANNED REMEDIAL MEASURES.
THE ABILITY TO ACHIEVE CLEAN UP GOALS AT ALL POINTS THROUGHOUT THE AREA
OF CONTAMINATION CANNOT BE DETERMINED UNTIL THE EXTRACTION SYSTEM HAS
BEEN IMPLEMENTED, MODIFIED AS NECESSARY AND PLUME RESPONSE MONITORED
OVER TIME. IF THE SELECTED GROUNDWATER PUMP AND TREAT REMEDY CANNOT
MEET THESE HEALTH BASED RESTORATION GOALS, AT ANY OR ALL OF THE
MONITORING POINTS DURING IMPLEMENTATION, THE CONTINGENCY MEASURES AND
GOALS MAY REPLACE THE SELECTED MEASURES AND GOALS FOR THESE PORTIONS OF
THE PLUME. SUCH CONTINGENCY MEASURES WILL, AT A MINIMUM, CONTAIN THE
PLUME TO WITHIN THE ZONE CURRENTLY EXCEEDING HEALTH-BASED LEVELS. THESE
CONTAINMENT MEASURES ARE STILL CONSIDERED TO BE PROTECTIVE OF HUMAN
HEALTH AND THE ENVIRONMENT, AND ARE TECHNICALLY PRACTICABLE UNDER THE
CIRCUMSTANCES.
THE SELECTED REMEDY WILL INCLUDE GROUND WATER EXTRACTION FOR AN UNKNOWN
PERIOD, DURING WHICH TIME THE SYSTEM'S PERFORMANCE WILL BE CAREFULLY
MONITORED ON A REGULAR BASIS AND ADJUSTED AS WARRANTED BY THE
PERFORMANCE DATA COLLECTED DURING OPERATION. MODIFICATIONS MAY INCLUDE
ANY OR ALL OF THE FOLLOWING:
A)
AT INDIVIDUAL WELLS WHERE CLEANUP GOALS HAVE BEEN
ATTAINED, PUMPING MAY BE DISCONTINUED;
B)
ALTERNATING PUMPING AT WELLS TO ELIMINATE STAGNATION
POINTS;
C)
PULSE PUMPING TO ALLOW AQUIFER EQUILIBRATION AND ENCOURAGE
ADSORBED CONTAMINANTS TO PARTITION INTO GROUND WATER; AND
D)
INSTALLATION OF ADDITIONAL EXTRACTION WELLS TO FACILITATE
OR ACCELERATE CLEANUP OF THE CONTAMINANT PLUME.
TO ENSURE THAT CLEANUP GOALS CONTINUE TO BE MAINTAINED, THE AQUIFER WILL
BE MONITORED AT THOSE WELLS WHERE PUMPING HAS CEASED ON AN OCCURRENCE OF
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-001-001
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EVERY ONE YEAR FOR A PERIOD OF FIVE YEARS FOLLOWING DISCONTINUATION OF
GROUND WATER EXTRACTION.
IF, IN EPA'S JUDGEMENT, IMPLEMENTATION OF THE SELECTED REMEDY CLEARLY
DEMONSTRATES, IN CORROBORATION WITH STRONG HYDROGEOLOGICAL AND CHEMICAL
EVIDENCE, THAT IT WILL BE TECHNICALLY IMPRACTICABLE TO ACHIEVE AND
MAINTAIN REMEDIATION GOALS THROUGHOUT THE AREA OF ATTAINMENT, THE
CONTINGENCY WILL BE IMPLEMENTED.
WHERE SUCH A CONTINGENCY SITUATION ARISES, GROUND WATER EXTRACTION AND
TREATMENT WOULD TYPICALLY CONTINUE AS NECESSARY TO ACHIEVE MASS
REDUCTION AND REMEDIATION GOALS THROUGHOUT THE REST OF THE AREA OF
ATTAINMENT.
SANGAMO PLANT SITE
GROUNDWATER AT THE SANGAMO PLANT SITE OCCURS PRIMARILY WITHIN THE JOINT
AND FRACTURE SYSTEM OF THE BEDROCK. GROUNDWATER DISCHARGE FROM WELLS
SURROUNDING THE RIDGE WOULD CONTAIN PRIMARILY VOCS. THIS WATER WOULD BE
TREATED BY AIR STRIPPING. GROUNDWATER DOWNGRADIENT OF AREAS A, B, E,
AND THE WASTE WATER TREATMENT FACILITY WOULD BE TREATED BY CARBON
ADSORPTION. IN THIS AREA, RI DATA SHOWED PCBS IN GROUNDWATER COLLECTED
FROM 10 OF 17 WELLS. VOCS HAVE BEEN DETECTED IN A MAJORITY OF THESE
WELLS. TREATED WATER WOULD BE DISCHARGED INTO TOWN CREEK.
BREAZEALE SITE
THE ASSUMED PUMPING SCHEME FOR THE BREAZEALE SITE CONSISTS OF
GROUNDWATER EXTRACTION WELLS SCREENED IN THE SATURATED PORTIONS OF THE
SAPROLITE AND FLOODPLAIN DEPOSITS.
EXTRACTED GROUNDWATER WOULD CONTAIN VOCS AND WOULD BE TREATED THROUGH
AIR STRIPPING AND/OR CARBON ADSORPTION (IF NECESSARY). TREATED WATER
WOULD BE DISCHARGED INTO WOLF CREEK.
DODGENS SITE
THE ASSUMED PUMPING SCHEME FOR THE DODGENS SITE CONSISTS OF GROUNDWATER
EXTRACTION WELLS SCREENED IN THE SATURATED PORTIONS OF THE SAPROLITE.
EXTRACTED GROUNDWATER IS EXPECTED TO CONTAIN VOCS AND AT LEAST ONE
SEMI-VOLATILE ORGANIC COMPOUND. COLLECTED GROUNDWATER WOULD BE TREATED
THROUGH AIR STRIPPING AND/OR CARBON ADSORPTION (IF NECESSARY). TREATED
WATER WOULD BE DISCHARGED TO MIDDLE FORK TWELVEMILE CREEK.
CROSS ROADS SITE
THE ASSUMED PUMPING SCHEME FOR THE CROSS ROADS SITE CONSISTS OF
GROUNDWATER EXTRACTION WELLS SCREENED IN THE SATURATED PORTIONS OF THE
SAPROLITE.
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Order number 940620-103843-ROD
-001-001
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EXTRACTED GROUNDWATER IS EXPECTED TO
HAZARDOUS SUBSTANCE LIST COMPOUNDS.
TREATED THROUGH AIR STRIPPING AND/OR
TREATED WATER WOULD BE DISCHARGED TO
CREEK.
CONTAIN VOCS AND POSSIBLY OTHER
COLLECTED GROUNDWATER WOULD BE
CARBON ADSORPTION (IF NECESSARY).
AN UNNAMED TRIBUTARY OF TWELVEMILE
SOURCE EXCAVATION AND TRANSPORTATION
THE FIRST STEP IN THIS ALTERNATIVE WOULD INCLUDE EXCAVATION OF SOLID
MATERIALS AFFECTED WITH GREATER THAN 1 PPM PCBS ON THE NIX AND WELBORN
PRIVATE PROPERTIES, GREATER THAN 10 PPM PCBS ON THE TROTTER, DODGENS,
BREAZEALE AND CROSS ROADS PROPERTIES AND 25 PPM PCBS AT THE PLANT SITE.
FOLLOWING EXCAVATION, THE MATERIALS WOULD BE TEMPORARILY STOCKPILED ON
THE PLANT SITE. THE MATERIAL TO BE REMEDIATED CONSISTS OF APPROXIMATELY
2,900 CUBIC YARDS OF SOLID WASTE AND APPROXIMATELY 48,200 CUBIC YARDS OF
CONTAMINATED SOIL AND SEDIMENT. THE LAGOON SEDIMENTS WOULD BE DREDGED
AND DEWATERED PRIOR TO TRANSPORT TO THE TREATMENT AREA. LIQUIDS
PRODUCED DURING DEWATERING WOULD BE TEMPORARILY STORED IN TANKS AND THEN
TRANSPORTED FOR TREATMENT IN THE LEACHATE TREATMENT UNIT AT THE ON-SITE
TSCA LANDFILL. THE AVERAGE HAUL DISTANCE FROM ON-SITE.EXCAVATION AREAS
WOULD BE LESS THAN APPROXIMATELY ONE-HALF MILE. THE AVERAGE HAUL
DISTANCE FROM REMOTE SITE EXCAVATION AREAS WOULD BE APPROXIMATELY 2.5
MILES. SOLIDS TREATED TO TWO PPM OR LESS IN THE THERMAL DESORPTION UNIT
WOULD BE DISPOSED OF ON-SITE. LIMITED FIELD TRIALS MAY BE REQUIRED TO
CONFIRM TREATMENT EFFECTIVENESS AND TO CHARACTERIZE TREATMENT RESIDUALS.
EACH OF THE TREATMENT PROCESS OPTIONS WOULD REQUIRE PRE-PROCESSING OF
THE SOLIDS TO REMOVE OVERSIZED ITEMS AND TO REDUCE THE PARTICLE SIZE.
THE ASSUMPTION OF A ONE PERCENT REJECTION RATE IS USED BECAUSE MUCH OF
THE AFFECTED AREAS ARE NOT COVERED WITH THICK STANDS OF TREES. THESE
MATERIALS WOULD REQUIRE OFF-SITE DISPOSAL AS A TSCA REGULATED WASTE IN A
PERMITTED LANDFILL.
EXCAVATED AREAS WILL BE BACKFILLED WITH NATIVE SOIL, GRADED, AND
RESTORED TO SUPPORT VEGETATION.
ANY POTENTIAL LONG-TERM MIGRATION AT GROUND SURFACE BY THE LOW
CONCENTRATIONS OF WASTE CONSTITUENTS THAT REMAIN IN PLACE WOULD BE
LIMITED BY PLACEMENT OF CLEAN BACKFILL.
SOURCE TREATMENT
THERMAL DESORPTION (OR THERMAL SEPARATION) IS A PROCESS OPTION RETAINED
FROM THE SCREENING OF THERMAL TREATMENT TECHNOLOGIES. A PROPRIETARY
SYSTEM REPRESENTED THE TECHNOLOGY IN THE FEASIBILITY STUDY REPORT
ANALYSIS. THIS RECORD OF DECISION IDENTIFIES THERMAL DESORPTION OR
SEPARATION AS THE PREFERRED TREATMENT ALTERNATIVE. EXACT DETAILS OF THE
PROCESS, INCLUDING TREATABILITY STUDIES WILL BE DEVELOPED AS PART OF THE
REMEDIAL DESIGN.
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Order number 940620-103843-ROD
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THE PROCESS ENVISIONED IS A MOBILE PROCESS IN WHICH SOILS OR SLUDGES
WITH ORGANIC COMPOUNDS ARE HEATED IN A ROTARY KILN. VOLATILIZED
ORGANICS ARE TRANSFERRED, USING NITROGEN AS THE CARRIER GAS, AND COOLED
TO CONDENSE ORGANIC COMPONENTS. THE CONDENSED COMPONENTS ARE THEN
COLLECTED FOR FURTHER TREATMENT AT AN APPROPRIATE FACILITY.
THIS SYSTEM WOULD CONSIST OF THE FOLLOWING TYPICAL UNIT OPERATIONS:
*
MATERIAL PREPROCESSING/SORTING
*
ROTARY KILN THERMAL SEPARATION
*
CARBON ADSORPTION UNIT (OR COMBUSTION AFTERBURNER)
*
COOLING AND CONDENSATE TRAIN
*
OFF-GAS HANDLING TRAILER
*
RESIDUALS MANAGEMENT UNIT
ON THE BASIS OF PILOT STUDIES, A TREATMENT CAPACITY OF FIVE TONS PER
HOUR CAN BE EXPECTED. ASSUMING A TYPICAL DENSITY OF APPROXIMATELY 1.3
TONS PER CUBIC YARD OF MATERIAL, THE ESTIMATED TIME EXPECTED TO COMPLETE
TREATMENT WOULD BE IN EXCESS OF TWO YEARS. THIS ESTIMATE IS BASED ON
THE USE OF ONE TREATMENT SYSTEM AND A MINIMUM OF 30 PERCENT DOWNTIME.
9.2 COST
THE COSTS FOR THIS ALTERNATIVE, ARE INCLUDED IN APPENDIX D OF THE
FEASIBILITY STUDY REPORT. THE ESTIMATED PRESENT-WORTH COST IS GIVEN
BELOW:
OPTION 11B:
THERMAL SEPARATION - $47,900,000 - 63,300,000
THE COSTS IN THIS ALTERNATIVE HAVE A POTENTIAL TO VARY FROM THE
ESTIMATED COSTS DUE TO SEVERAL FACTORS:
*
UNKNOWN HYDRAULIC CHARACTERISTICS OF THE AQUIFER.
IN-FIELD TESTS PRIOR TO AND DURING THE REMEDIAL DESIGN ARE
REQUIRED TO FULLY CHARACTERIZE THE SITE HYDROLOGIC
PROPERTIES.
*
UNPREDICTABLE FLOW AND CONSTITUENT REMOVAL RATES.
*
VOLUME OF EXCAVATED SOLIDS MAY EXCEED THE LANDFILL DESIGN
VOLUME.
STATUTORY DETERMINATIONS
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Order number 940620-103843-ROD
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THE SELECTED REMEDY SATISFIES THE REQUIREMENTS OF SECTION 121 OF CERCLA.
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT:
THE SELECTED REMEDY WILL PERMANENTLY TREAT THE GROUNDWATER AND SOIL AND
REMOVES OR MINIMIZES THE POTENTIAL RISKS ASSOCIATED WITH THE WASTES.
DERMAL, INGESTION, AND INHALATION CONTACT WITH SITE CONTAMINANTS WOULD
BE ELIMINATED, AND RISKS POSED BY CONTINUED GROUNDWATER CONTAMINATION
WOULD BE REDUCED.
ATTAINMENT OF ARARS:
THIS ALTERNATIVE WILL COMPLY WITH ARARS. A COMPLETE DISCUSSION OF THE
ARARS WHICH ARE REQUIRED TO BE ATTAINED IS INCLUDED IN CHAPTER 8.
CHAPTER 8 ALSO DESCRIBES THOSE REQUIREMENTS CONSIDERED AS TBCS (TO BE
CONSIDERED).
(TABLE 6.6).
GROUNDWATER CLEAN-UP CRITERIA ARE ADDRESSED IN CHAPTER 6
COST-EFFECTIVENESS:
THE GROUNDWATER AND SOURCE REMEDIATION TECHNOLOGIES ARE MORE
COST-EFFECTIVE THAN THE OTHER ALTERNATIVES CONSIDERED PRIMARILY BECAUSE
THEY PROVIDE GREATER BENEFIT FOR THE COST.
UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM EXTENT
PRACTICABLE
THE SELECTED REMEDY REPRESENTS THE MAXIMUM EXTENT TO WHICH PERMANENT
SOLUTIONS AND TREATMENT CAN BE PRACTICABLY UTILIZED FOR THIS ACTION. OF
THE ALTERNATIVES THAT ARE PROTECTIVE OF HUMAN HEALTH AND THE ENVIRONMENT
AND COMPLY WITH ARARS, EPA AND THE STATE HAVE DETERMINED THAT THE
SELECTED REMEDY PROVIDES THE BEST BALANCE OF TRADE-OFFS IN TERMS OF
LONG-TERM EFFECTIVENESS AND PERMANENCE, REDUCTION IN TOXICITY, MOBILITY
OR VOLUME ACHIEVED THROUGH TREATMENT, SHORT-TERM EFFECTIVENESS,
IMPLEMENTABILITY, COST AND ALSO CONSIDERING THE STATUTORY PREFERENCE FOR
TREATMENT AS A PRINCIPAL ELEMENT AND ALSO CONSIDERING STATE AND
COMMUNITY ACCEPTANCE.
PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
THE PREFERENCE FOR TREATMENT IS SATISFIED BY THE USE OF THE LOW
TEMPERATURE THERMAL TREATMENT SYSTEM TO REMOVE CONTAMINATION FROM SOIL,
SEDIMENTS AND WASTE AT THE SITE AND THE USE OF AIR STRIPPING/CARBON
ADSORPTION TO TREAT CONTAMINATED GROUND WATER AT THE SITE. THE
PRINCIPAL THREATS AT THE SITE WILL BE MITIGATED BY USE OF THESE
TREATMENT TECHNOLOGIES.
#TA
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Order number 940620-103843-ROD
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TABLE 5-9
PCB(1) CONCENTRATIONS DETECTED IN SURFACE SOILS:
NIX SITE
SAMPLE NO.
NXSS-1
NXSS-2
NXSS-3
NXSS-4
NXSS-5
NXSS-6
NXSS-7
NXSS-8
PCB CONCENTRATION
AROCLOR 1248
AROCLOR 1254
0.32
ND
ND
1.1
ND
0.75
24.
0.538
0.36
0.13
ND
2.5
ND
0.41
16.
0.65
TOTAL
0.68
0.13
ND
3.6
ND
1.16
40.
1.168
NXSS-9
NXSS-10
NXSS-11
NXSS-12
NXSS-13
NXSS-14
NXSS-15
NXSS-16
NXSS-16 DUPLICATE
NXSS-17
NXSS-18
NXSS-19
NXSS-20
NXSS-21
NXSS-22
ND
(1)
4.1
ND
0.75
ND
19.
13.
ND
7.8
8.1
ND
ND
ND
ND
ND
ND
5.5
ND
2.8
0.26
47.
15.
6.6
15.
15.
0.51
ND
ND
ND
0.24
13.
9.6
ND
3.55
0.26
66.
28.
6.6
22.8
23.
0.51
ND
ND
ND
0.24
13.
NONE DETECTED.
CONCENTRATIONS ARE IN PARTS PER MILLION (DRY WEIGHT).
LISTED ARE THE ONLY AROCLORS DETECTED.
AROCLORS
TABLE 5-10
PCB CONCENTRATIONS DETECTED IN SUBSURFACE SOILS:
NIX SITE
SAMPLE IDENTIFICATION
(BORING NO. &
SAMPLE INTERVAL)
NXSB-1 (3.5-5.0)
NXSB-2 (3.5-5.0)
NXSB-3 (4.0-6.0)
NXSB-3A (4.0-6.0)
NXSB-3B (2.5-4.0)
NXSB-3B (5.0-6.5)
PCB CONCENTRATION(1)
AROCLOR 1248
AROCLOR 1254 TOTAL PCBS
ND
ND
ND
ND
ND
ND
ND
ND
0.06
ND
ND
ND
ND
ND
0.06
ND
ND
ND
0.4
NA
ND
ND
ND
0.4
NA
ND
ND
ND
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Order number 940620-103843-ROD
-001-001
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set 4 with 100 of 100 items
NXSB-4 (2.0-4.0)
NXSB-4 (4.0-4.8)
NXSB-4, 4A, 4B
NXSB-5 (3.5-5.0)
NXSB-5 (3.5-5.0) DUPLICATE
ND
NA
ND
ND
ND
ND - NONE DETECTED
ND - NOT ANALYZED
(1)
CONCENTRATIONS ARE IN PARTS PER MILLION (DRY WEIGHT).
AROCLORS LISTED ARE THE ONLY AROCLORS DETECTED.
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION
Site Information:
Address:
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION
PICKENS, SC
EPA ID:
EPA Region:
SCD003354412
04
Site Name:
Site Alias Name(s):
SANGAMO/TWELVE-MILE/HARTWELL PCB
SANGAMO WESTON-PICKENS PLANT
HAYWOOD RESERVOIR
MIDWAY LANDFILL
CROSS ROADS CHURCH
BREZEAL PROPERTY
WELLBORN PROPERTY
MAW BRIDGE ROAD
NIX, ERNEST PROPERTY
SANGAMO ELECTRIC
SANGAMO PROPERTY
SANGAMO WESTON/TWELVE-MILE/HARTWELL PCB
Record of Decision (ROD) - Explanation of Significant Differences (ESD):
ROD Date:
Operable Unit:
ROD ID:
09/10/1991
01
EPA/ESD/R04-91/501
Text:
Full-text ROD document follows on next page.
EPA/ESD/R04-91/501
1991
EPA Superfund
Explanation of Significant Differences:
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION
EPA ID: SCD003354412
OU 01
PICKENS, SC
09/10/1991
1
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV
SUPERFUND PROGRAM EXPLANATION OF SIGNIFICANT DIFFERENCES
SANGAMO WESTON/TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION SITE
OPERABLE UNIT ONE
PICKENS, PICKENS COUNTY, SOUTH CAROLINA
Introduction
The purpose of this Explanation of Significant Differences (ESD)
is to provide factual information to the public regarding a
change in remedial activities for the Sangamo Weston/Twelve-Mile
Creek/Lake Hartwell PCB Contamination Site, Operable Unit #1, in
Pickens County, South Carolina (Site). In addition, this ESD
explains the process that the Environmental Protection Agency
(EPA) will follow to provide for a remedy which is protective of
human health and the environment with respect to inorganic
contamination (metals) at the Site. This ESD modifies the
existing Record of Decision (ROD) by identifying metals in the
soils and in the groundwater that have been found in amounts that
may exceed acceptable health based levels. The ESD also modifies
the ROD by adding clean up criteria for metals contamination in
the groundwater and provides for additional testing and data
gathering for metals at the Site. After this data is gathered,
EPA will make a future determination regarding the necessity of
remedying the metals contamination through an additional ESD or a
ROD amendment. This ESD also clarifies the PCBs excavation
standard selected in the ROD for two areas of the Site, and
explains a response made by EPA to a comment received during a
public meeting held to discuss the ROD.
This Explanation of Significant Differences (ESD) is issued as an
EPA public participation responsibility pursuant to Section
117(c) of the Comprehensive Environmental Response, Compensation
and Liability Act (CERCLA), as amended by Superfund Amendments
and Reauthorization Act (SARA), and Section 300.435(c)(2)(i) of
the National Contingency Plan (NCP) 40 C.F.R. Part 300.
The administrative record file for the Site contains the
information upon which this ESD was based, and includes the ROD
for Operable Unit #1. This ESD will become part of the
administrative record which is located at the following
locations:
Pickens County Library, Pickens S.C.
Village Library, Pickens S.C.
Hart County Library, Hartwell Ga.
R. M. Cooper Library at Clemson University
-2Background
The remedy for the Sangamo/Weston/Twelve Mile Creek/Lake Hartwell
site is presently divided into two Operable Units. Operable Unit
#1 (OU-1) will address that portion of the site consisting of the
seven parcels of property where PCBs, VOCs and metals were
released into the soils and groundwater (the Sangamo/Weston plant
property, the Nix, Welborn, Dodgen’s, Breazeale, Trotter and
Cross Roads properties). All seven of the properties are located
in Pickens County, South Carolina. This ESD modifies only the ROD
for OU-1. Throughout this ESD the term Site (upper case) is used
to mean the seven properties described above. These locations are
identified on the map included as Attachment A.
The remedial action for polychlorinated biphenyls (PCBs) and
volatile organic compounds (VOCs) contamination at the Site is
detailed by EPA in the ROD signed on December 19, 1990. In
summary, the remedy selected in the ROD consists of groundwater
remediation for PCBs and VOCs using pump and treat technology at
the Dodgens, Breazeale, Cross Roads, and Plant properties; and
the excavation of PCB and VOC contaminated soils at the Plant
property and the six satellite properties. The excavated soils
will be treated at the Plant property utilizing thermal
separation technology.
Site History
Sangamo Weston Inc., owned and operated a capacitor manufacturing
facility at the Plant property. The Pickens facility began
operation in 1955 and continued operating until May 1987, when
Sangamo Weston sold the operation and leased the buildings and a
portion of the property to another manufacturer. On December 31,
1989, Sangamo Weston merged with Schlumberger Industries, Inc.,
(SII). SII is the present owner of the plant property portion of
the Site. Between approximately 1955 and 1977 the facility
manufactured capacitors which used a dielectric fluid that
contained PCBs. During the manufacturing process, capacitors were
inspected and tested, and those that failed to meet quality
control criteria were discarded along with other wastes from the
plants operation. Some of these wastes were disposed of on the
Site.
Description of the Remedy
The ROD specifies that soils contaminated with PCBs and VOCs will
be excavated and treated through Thermal Separation. This
treatment technology consists of a low
-3temperature thermal heating unit which vaporizes PCBs and VOCs
from the soil and recondenses them into a concentrated form so
that they may be properly disposed of at an appropriate facility.
PCB and VOC contaminated soils will be excavated from the Site
until acceptable health based levels specified in the ROD are
reached. All excavated PCB contaminated soil material will be
transported to the Plant property and will be treated by the
Thermal Separation unit to residual PCB levels of 2 parts per
million (ppm) or less. The treated soil will then be disposed of
on the plant property. Because Thermal Separation is considered
an innovative technology, treatability studies will be performed
to determine if the technology will achieve the clean-up level of
2 ppm. If the treatability studies show that Thermal Separation
is ineffective for all or a portion of the contaminated soils,
EPA may, if necessary, formally amend the ROD to choose a new
technology for remediation of the contaminated soils.
The remedy selected in the ROD for groundwater contaminated with
PCBs and VOCs is to pump contaminated water and treat it using
air stripping and/or carbon adsorption technology. Groundwater
will be pumped until clean-up levels specified in the ROD are met
or until such time as EPA determines that such clean-up levels
are impracticable to achieve and that contingency measures should
be implemented. Pumped groundwater will be treated to meet all
Applicable or Relevant and Appropriate Requirements (ARARS), such
as Clean Water Act NPDES effluent limitations, before being
discharged to nearby existing water bodies such as creeks, and
tributaries.
Description of Significant Differences
After the ROD was signed EPA determined that the ROD did not
address several metals which had been listed as Constituents of
Concern in Table 6-1 of the Appendix to the ROD. Upon further
review of the sampling data gathered during the initial phases of
the Remedial Investigation, EPA has determined that metals
contamination at the Site may have been dismissed prematurely
during the Remedial Investigation Feasibility Studies (RI/FS)
process.
EPA has two concerns: 1) whether metals concentrations in the
groundwater at the Site exceed maximum contaminant levels (MCLs)
established by EPA for groundwater; and 2) whether the
concentrations of certain metals in soils and waste at the Site
might exceed acceptable health and risk based levels deemed to be
protective of human health and the environment.
-4A) Groundwater
Limited groundwater sampling and analysis from the initial phases
of the Remedial Investigation identifies metals in excess of MCLs
in the groundwater at five of the satellite properties and at the
Plant property. This sampling data is attached as Appendix B.
The metals listed on the chart below have been found in
groundwater at areas of the Site in levels exceeding MCLs.
Through this ESD, EPA is modifying the ROD to add the MCLs for
the listed metals as clean-up criteria at the Site.
EPA has also determined that further groundwater sampling at all
areas of the Site is necessary (including the possible
installation of additional monitoring wells) to delineate the
nature and extent of the metals contamination and to determine if
there is a demonstrated plume of metal contamination requiring
remediation.
At the properties where pump and treat remedial technology is
presently called for in the ROD, groundwater will be pumped until
MCLs for the listed metals, as well as the PCB and VOC levels
specified in the ROD, are reached. Utilizing the additional
sampling data called for in this ESD, EPA will make a future
determination as to what addition remedial technology, if any,
will be necessary to treat pumped groundwater containing metals.
EPA will also determine if groundwater at any additional
properties (Nix, Welborn and Trotter) needs to be remediated for
metals. EPA will incorporate these determinations into the ROD
through an additional ESD or a ROD amendment after a public
comment period. The clean-up criteria listed below shall also be
incorporated into such additional ESD or ROD amendment. The
following chart lists the metals of concern and the appropriate
MCL clean-up levels for each metal.
METALS
MCL CLEAN UP CRITERIA
Arsenic
0.050 ppm
Beryllium
0.001 ppm
Cadmium
0.005 ppm
Chromium
0.100 ppm
Lead
0.015 ppm(1)
Thallium
0.001 ppm
-5B) Soils
Based on the limited sampling and analysis data presently
available regarding metals in the soils at the Site, EPA has
determined that metals found in the soils may exceed acceptable
health based risk levels. Utilizing existing data, EPA has
identified metals in the soils which may require additional
remediation, but needs additional information on specific
conditions at the Site to calculate acceptable metal
concentration levels. Therefore, EPA has determined that
additional soil sampling activities for metals will be conducted
at the Site. These data gathering activities will enable EPA to
develop acceptable levels for metals in the surface and
subsurface soils and will allow EPA to determine the geographic
extent of the metals soil contamination at the Site. Following
review of the new data, EPA will make a determination of what
additional soil clean-up criteria and additional remedial
technology, if any, will be needed to remediate the metal
contaminated soil. EPA will incorporate any new soil clean-up
criteria and remedial technology into the ROD through an
additional ESD or ROD amendment after a public comment period.
EPA will calculate the acceptable subsurface soil concentration
criteria utilizing test procedures to establish soil partition
coefficients which will establish the mobility of the metals in
the soils and subsequently, through modeling, establish a
concentration that is protective of groundwater. Acceptable
surface soils concentration criteria will be developed based on
direct exposure routes.(2)
The following chart lists the metals which may exceed acceptable
health based levels at the Site.
INORGANIC METALS CONTAMINANT
Arsenic (3)
Chromium (4)
Lead (5)
Thallium (6)
Beryllium (7)
Cadmium (8)
-6PCB Excavation Levels For The Nix and Welborn Properties
This ESD also clarifies the excavation clean-up criteria for PCB
contaminated soils at the Nix and Welborn properties. The ROD
presently calls for the excavation of all contaminated soils at
the Nix and Welborn properties having greater than 1 ppm of PCBs.
However, the l ppm level called for in the ROD is based on the
concern that at the ravines located on the two properties,
erosion factors are too severe to assure that a 2 foot backfill
of clean soil would remain in place.
Where EPA determines that erosion is not a concern on the two
properties, PCB contaminated soils will be excavated to the
levels specified in the ROD for the four possible future
residential properties (Trotter, Dodgens, Breazeale, and Cross
Roads), i.e. requiring excavation to 10 ppm PCBs with a backfill
cover of 2 feet of clean soil. The final EPA determination
regarding erosion and/or backfilling at the two properties will
be made during the Remedial Design phase.
Clarification of Prior EPA Response to Public Comments
Upon review of the Responsiveness Summary, (ROD Appendix C), EPA
identified a response to a question received during a public
meeting that may have been unclear. The original comment and
response as stated on pages 15 and 16 of the Responsiveness
Summary is as follows:
An attendee commented that ground-water contamination has
existed for ten years and that hazardous waste continues to
leach into the ground water. The attendee asked whether it was
possible for EPA to conduct a short-term removal action at the
site, such as excavating the soil which is leaching into the
ground water.
EPA RESPONSE: Removals are performed where imminent and
substantial endangerment is posed by a hazardous waste site.
In this case, no imminent threat exists because no one is
drinking the groundwater; no one is exposed at this point. The
leaching, to a great extent, has already taken place and is
slow. Part of the remedy is to excavate and treat the soil.
Excavating and stockpiling it prior to completion and approval
of a treatment design, however, could create a problem
elsewhere.
7
By this response, EPA did not intend to suggest that an imminent
and substantial endangerment to public health and the environment
does not exist at the Site. The intent of EPA and the responder
was to say that an immediate threat to public health
necessitating use of EPA’s removal authority has not been
demonstrated by conditions at the Site.
Support Agency Comments
South Carolina’s Department of Health and Environmental Control
has reviewed this ESD and concurs with its contents.
Statutory Determinations
The modifications made to the ROD by this ESD are designed to
assure that the remedy at the Site will be protective of human
health and the environment, and will comply with Federal and
State requirements that are applicable or relevant and
appropriate.
After the additional data called for in this ESD has been
gathered and evaluated, EPA will use an additional ESD or a ROD
amendment to modify the ROD to incorporate any additional
necessary clean-up criteria for metals and to choose necessary
additional remedial technologies for metals. Any additional ESD
or ROD amendment will include a public comment period.
8
FOOTNOTES
(1) In reviewing the initial data for lead contamination, EPA
used the old MCL of 0.050 ppm. However, EPA Headquarters
Superfund Program had set a Superfund Program Action level for
lead clean-up at the lower level of .015 ppm. The rationale for
this health based clean-up level is explained in memorandum to
EPA Region IV, dated June 21, 1990 and attached as Appendix C).
(2) Surface soils were sampled for metals at the Welborn
property. The Welborn sampling was limited to lead, barium and
zinc. The soils data available for the remaining properties are
for the waste areas and subsurface soils. Based on this
information and data regarding metals found at elevated levels in
the groundwater, EPA has determined that the listed metals may be
present at levels of concern in surface soils. The surface soil
clean-up criteria will be calculated based on direct contact
exposure routes. Subsurface soil cleanup concentrations will be
calculated to protect groundwater. Should the cleanup criteria
for subsurface soils be lower than those calculated for surface
soils the lower criteria shall be the clean-up goal for all
soils.
(3) Based on averaged background levels for the surrounding
area.
(4) Assumes <10% hexavalent chromium present. Further sampling
will be done to confirm this assumption. If EPA can not confirm
the percentage of hexavalent chromium at the Site it will
determine the acceptable risk levels based on the worst case
scenario of the presence of 100% hexavalent chromium. 100%
Hexavalent Chromium at the Site would lower the clean-up level.
(5) Consistent with SUPERFUND Policy pursuant to OSWER Directive
9355.4-02.
(6) Thallium was detected in groundwater at levels exceeding
MCLs. It was not detected in unacceptable levels in the existing
soil samples. However, because thallium was detected it the
groundwater it is listed herein. The surface soil remediation
goal for thallium will be based on the chemical-specific
noncarcinogenic reference dose for the oral exposure route. The
subsurface remediation goal will be set at the level that is
protective of groundwater.
9
(7) Beryllium was detected in several waste and subsurface soils
exceeding the acceptable risk levels for direct contact through
surface soils. The remediation surface soil goal will based on
oral and inhalation carcinogenic slope factors. The subsurface
soil remediation goal will be set at the level that is protective
of the groundwater.
(8) Cadmium was detected in groundwater at levels exceeding MCLs.
It was not detected in unacceptable levels in existing soil
samples. However, because cadmium was detected in the groundwater
it is listed herein. The surface soil remediation goal for
Cadmium will be based on the chemical-specific noncarcinogenic
reference dose for the oral exposure route. The subsurface soil
remediation goal will be set to the level that is protective of
the groundwater.
ATTACHMENT B
METAL
MCL
SAMPLE #
CONCENTRATION
Arsenic
.050 PPM
JTMW-3
.213 PPM
Beryllium
.001 PPM
JTMW-3
.007 PPM
Cadmium
.005 PPM
CRMW-3
.011 PPM
Chromium
.100 PPM
JTMW-3
.190 PPM
Thallium
.001 PPM
SWMW-4
.016 PPM
Lead
.015 PPM
WBMW-3
JTMW-3
CRMW-3
DGMW-3
NXMW-3
SWMW-6
.054
.093
.055
.038
.020
.063
PPM
PPM
PPM
PPM
PPM
PPM
ATTACHMENT C
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
WASHINGTON, D.C. 20460
OFFICE OF
SOLID WASTE AND EMERGENCY RESPONSE
JUN 21 1990
MEMORANDUM
SUBJECT:
Cleanup Level for Lead in Ground Water
FROM:
Henry L. Longest, Director
Office of Emergency and Remedial Response
Bruce M. Diamond, Director
Office of Waste Programs Enforcement
TO:
Patrick M. Tobin, Director
Waste Management Division, Region IV
PURPOSE
This memorandum addresses the issue of a protective cleanup
level for lead in ground water usable for drinking water, which
is a major concern for several Superfund sites in Region IV.
OBJECTIVE
The objective of this memorandum is to recommend a final
cleanup level for lead in ground water usable for drinking water
which will meet the CERCLA requirement that all Superfund
remedies be protective of human health and the environment.
BACKGROUND
The current Maximum Contaminant Level (MCL) for lead is 50
ppb and was promulgated in 1975 as an interim national primary
drinking water regulation (NPDWR) under the Safe Drinking Water
Act (SDWA). On November 13, 1985, the Agency began the process of
revising this standard by proposing a Maximum Contaminant Level
Goal (MCLG) as required by the SDWA (50 FR 46936).
On August 18, 1988 EPA proposed an MCLG for lead at zero and
an MCL of 5 ppb (53 FR 31516). Also, since the primary cause of
lead-contaminated drinking water is corrosion of lead-bearing
pipes in public water supply (PWS) distribution systems and/or
household plumbing, the proposed rule would direct PWSs to meet
treatment technique requirements and to deliver public education
to reduce and minimize exposures to lead in drinking water.
-2These requirements would be triggered when an action level
is exceeded at consumers’ taps throughout the water distribution
system. The Agency proposed an action level of 10 ppb, on
average, to trigger corrosion control and public education.
Another lead action level of 20 ppb, measured at the 95
percentile of samples, was proposed as a trigger for public
education.
The Agency is considering promulgation of treatment
technique requirements which may include additional source water
treatment, lead service connection replacement, and public
education if lead concentrations at the tap exceed an action
level. Any such technological treatment targets will provide
substantial health protection. A final rule is being worked on,
and is scheduled for promulgation in December 1990.
DISCUSSION
No cancer potency factor or reference dose has been
promulgated for lead; therefore, an assessment of protective
levels of lead in ground water that may be used for drinking
water purposes will be based on current data. The Agency has
identified 10 micrograms per deciliter (ug/dl) as a blood lead
level of concern in young children. Blood lead levels above 10
ug/dl are associated with increased risks of potentially adverse
effects on neurological development and diverse physiological
functions.
Attached is available data that support the recommended
final cleanup level for lead in drinking water at Superfund
sites. This information includes the June 15, 1990, EPA draft
final report entitled, “Contributions To a Risk Assessment For
Lead in Drinking Water” and the June 1986, EPA draft final report
entitled, “Air Quality Criteria for Lead” (Volume III of IV, p.
11-129). Based on these data, lead levels in drinking water of 15
ppb and lower should correlate to blood lead levels below the
concern level of 10 ug/dl. The Agency estimates that steady
exposure to a water lead concentration of 15 ppb would
contribute, at most, 2-3 ug/dl to a child’s blood lead. Sources
of lead other than drinking water (e.g. food, air, soil, dusts)
typically contribute approximately 4-5 ug/dl to children’s blood
lead. Accounting for the variability inherent in childhood
behavior, nutrition, and physiology, it is estimated that total
lead exposure, given 15 ppb in drinking water, would result in
blood lead levels below 10 ug/dl in
-3roughly 99 percent of young children who are not exposed to
excessive lead paint hazards or heavily contaminated soils.
Therefore, a 15 ppb cleanup level would provide substantial
health protection for the majority of young children. Most of the
remaining lead problem will continue to be contaminated soils and
old lead-painted housing.
In an April 10, 1989, Federal Register notice (54 FR 14316),
EPA announced the availability of a guidance document and testing
protocol entitled, “Lead in School’s Drinking Water,” to assist
schools in determining the source and degree of lead
contamination in school drinking water supplies and how to remedy
such contamination. That document, which is also attached,
recommends that schools take remedial steps whenever the lead
level at any drinking water outlet exceeds 20 ppb.
RECOMMENDATION
Based on a review of these and other studies, it is
recommended that a final cleanup level of 15 ppb for lead in
ground water usable for drinking water is protective. If water
used for drinking purposes subsequent to achieving the cleanup
goal in the aquifer may need further treatment to account for
lead contributions related to the distribution of water through
pipes, the responsibility for this additional treatment or the
replacement of lead-bearing water pipes lies with the persons who
are using or distributing the water. A concentration of lead of
15 ppb in drinking water should generally correlate with a blood
lead level below the concern level of 10 ug/dl. In some
situations, lower cleanup levels may be appropriate based on
site-specific factors, such as multiple pathways of exposure
caused by lead from the site.
If the remedial action will include treatment and supplying
water directly to the public for drinking water consumption,
compliance with a 15 ppb action level should be met at 90 percent
of the taps to ensure that the remedy is protective. When the
lead NPDWR is promulgated, applicable or relevant and appropriate
requirements of that rule should be met.
FUTURE GUIDANCE
After promulgation of the lead NPDWR, guidance will be
issued discussing those provisions of the rule that may be
applicable or relevant and appropriate for Superfund actions.
For further information, please contact Tish Zimmerman at
FTS 382-2461 or Neilima Senjalia at FTS 475-7027.
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION
Site Information:
Address:
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION
PICKENS, SC
EPA ID:
EPA Region:
SCD003354412
04
Site Name:
Site Alias Name(s):
SANGAMO/TWELVE-MILE/HARTWELL PCB
SANGAMO WESTON-PICKENS PLANT
HAYWOOD RESERVOIR
MIDWAY LANDFILL
CROSS ROADS CHURCH
BREZEAL PROPERTY
WELLBORN PROPERTY
MAW BRIDGE ROAD
NIX, ERNEST PROPERTY
SANGAMO ELECTRIC
SANGAMO PROPERTY
SANGAMO WESTON/TWELVE-MILE/HARTWELL PCB
Record of Decision (ROD) - Explanation of Significant Differences (ESD):
ROD Date:
Operable Unit:
ROD ID:
06/18/1993
01
EPA/ESD/R04-93/502
Text:
Full-text ROD document follows on next page.
EPA/ESD/R04-93/502
1993
EPA Superfund
Explanation of Significant Differences:
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION
EPA ID: SCD003354412
OU 01
PICKENS, SC
06/18/1993
U.S. ENVIRONMENTAL PROTECTION AGENCY
REGION IV SUPERFUND PROGRAM
EXPLANATION OF SIGNIFICANT DIFFERENCES
Sangamo Weston/Twelve-Mile Creek/Lake Hartwell
PCB Contamination Site
Operable Unit One
Pickens, Pickens County, South Carolina
1.0
Introduction
The purpose of this Explanation of Significant Differences (ESD) is to
provide factual information to the public regarding changes in proposed
remedial activities for the Sangamo Weston/Twelve-Mile Creek/Lake
Hartwell PCB Contamination Site, Operable Unit One, located in Pickens
County, South Carolina, hereinafter referred to as the Site.
First, this ESD explains the results of EPA’s evaluation of inorganic
contamination (metals) at the Site. This evaluation was performed
pursuant to a previous ESD dated September 10, 1991. This ESD modifies
the existing Record of Decision (ROD) for the Site by concluding that
metals contamination of surface soils and ground water does not pose an
unacceptable level of risk to human health or the environment. The
results of analyses of ground-water and soil samples taken at the seven
individual locations which comprise the overall Site are presented. The
results of analyses for metals in these samples indicate that metals
contaminant concentrations in the ground water do not exceed the
appropriate ground-water protection criteria for the Site and that
surface soils are not contaminated above health-based criteria
established by standard risk assessment procedures.
Second, this ESD modifies the existing ROD by updating the ground-water
remediation criteria. At the time that the previous ESD was prepared,
ground-water remediation criteria for the contaminants beryllium and
thallium were both set at 0.001 part per million (ppm), equivalent to 1
part per billion (ppb). These remediation criteria were based upon
toxicological data related to health effects caused by exposure to these
contaminants, but EPA had not at that time promulgated drinking water
standards (known an Maximum Contaminant Levels, or MCLs) for beryllium
or thallium. In July, 1992, EPA published in the Federal Register final
MCLs for beryllium and thallium. These MCLs are 4 ppb and 2 ppb,
respectively. This ESD modifies the existing ROD (as modified in turn by
the previous ESD) by adopting the promulgated MCLs as ground-water
remediation criteria for beryllium and thallium.
Third,
this
ESD
also
modifies
the
existing
ROD
for
the
Site
by
2
waiving certain specific applicable requirements identified in the ROD
for the storage of PCB wastes. Under the terms of the National
Contingency Plan (NCP), EPA has established criteria by which the Agency
may waive applicable or relevant and appropriate requirements (ARARs)
identified during the RI/FS process. EPA has determined that the ARAR
requiring the construction of a storage facility complying with the
requirements of regulations established pursuant to the authority of the
Toxic Substances Control Act (TSCA) should be waived according to these
criteria.
This ESD is issued as an EPA public participation responsibility
pursuant to Section 117(c) of the Comprehensive Environmental Response,
Compensation and Liability Act (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act (SARA), and Section 300.435(c)(2)(i)
of the NCP, 40 CFR Part 300. EPA intends to solicit public comment
regarding this ESD for a 30-day period.
The administrative record for this Site contains the information upon
which this ESD is based, and includes the ROD for Operable Unit One.
This ESD will become part of that administrative record which may be
found at the following locations:
Pickens County Library, Pickens, SC
Village Library, Pickens, SC
Hart County Library, Hartwell, GA
R.M. Cooper Library, Clemson University, Clemson, SC
2.0
Background
The remedy for the Site is presently divided into two Operable Units.
Operable Unit One (OU1) will address that portion of the Site generally
consisting of seven parcels of property where polychlorinated biphenyls
(PCBs), volatile organic chemicals (VOCs), and metals were released into
the soils and ground water. These seven parcels are the Sangamo Weston
plant property and six private parcels located in the vicinity of the
town of Pickens, SC, in Pickens County. These six outlying or satellite
disposal sites are known as the Breazeale, Crossroads, Dodgens, Nix,
Trotter and Welborn sites. This ESD modifies only the ROD for OU1.
Throughout this ESD the term Site (upper case) is used to mean the seven
properties described above. These locations are identified on the map
included as Appendix A.
The remedial action for PCBs and VOCs contamination at the Site is
described in detail in the ROD signed on December 19, 1990. In summary,
the remedy selected in the ROD consists of ground-water remediation for
PCBs and VOCs using ground-water extraction and treatment at the Plant,
Breazeale, Crossroads and Dodgens sites; and excavation of soils
contaminated with PCBs and VOCs at the Plant property and at the six
satellite sites. All excavated soils
3
will be treated at the plant property by means of low temperature
thermal desorption (LTTD), a thermal separation technology.
On September 10, 1991, EPA issued an ESD for OU1 at this Site that
identified inorganic contaminants (metals) found during the Remedial
Investigation (RI) that may have exceeded criteria based upon the
protection of human health.
That ESD also modified the ROD by
establishing remedial criteria for metals contamination in ground water
and by providing for additional testing and data gathering for the
purpose of evaluating compliance with those criteria. The previous ESD
also clarified the criteria established for PCB excavation at two of the
satellite sites, and contained an explanation of a response made by EPA
to a comment raised during a public meeting held to discuss the ROD for
the Site. Finally, the previous ESD committed EPA to evaluate the data
gathered on metals contamination and to make a determination regarding
the necessity of providing remediation for metals contamination by means
of a future ESD or ROD amendment.
3.0
Site History
Sangamo Weston, Inc., owned and operated a capacitor manufacturing
facility at the Plant property. This manufacturing activity began in
1955, and was continued by Sangamo Weston until May, 1987, when Sangamo
Weston sold the operation and leased the buildings and a portion of the
Plant site property to another manufacturer. On December 31, 1989,
Sangamo Weston merged with Schlumberger Industries, Inc., (SII). SII is
the present owner of the Plant property portion of the Site. During the
approximate period l955-1977, the facility manufactured capacitors which
used a dielectric fluid which contained PCBs. During the manufacturing
process, capacitors were tested and inspected, and those that failed to
meet quality control criteria were discarded along with other wastes
from the plant operation. Some of these wastes were disposed of in the
seven parcels that comprise the Site.
4.0
Description of the Remedy
The ROD specifies that soils contaminated with PCBs and VOCs will be
excavated and treated by means of LTTD. This treatment technology
consists of a low temperature thermal heating unit which vaporizes PCBs
and VOCs from contaminated soils and waste materials and recondenses
them into a concentrated form so that they may be properly disposed of
at an appropriate facility.
Soils and waste material contaminated with PCBs and VOCs will be
excavated from the Site until acceptable levels, based on the protection
of human health as specified in the ROD, are achieved. All excavated
soils and waste materials contaminated with PCBs and VOCs will be
transported from the six satellite sites to the Plant site and will be
treated at that location using the LTTD
4
technology. Excavated soils and waste material from the Plant site will
also be treated at this location using the same LTTD system. All
contaminated soils and wastes will be treated to a residual PCB
concentration of 2 parts per million (ppm) or less. The treated soils
will then be disposed of on the Plant site property. Due to the fact
that LTTD is considered to be an innovative technology, treatability
studies are being performed to determine if the technology can achieve
the specified performance standard of 2 ppm residual PCBs. Should the
treatability studies demonstrate that LTTD is ineffective for all or a
portion of the contaminated soils and waste materials, EPA may, if
necessary, amend the ROD to specify an alternative treatment technology
for remediation of these media.
With respect to contaminated ground waters at the various sites, the
remedy selected in the ROD consisted of extraction and treatment to
levels meeting ARARs or other criteria determined to be protective of
human health. The treatment technology identified in the ROD is a
combination of air stripping and/or carbon adsorption as necessary to
achieve ARARs for the discharge of treated ground waters to surface
waters. Extraction of contaminated ground water will continue until such
time as the ground-water remediation criteria specified in the ROD are
achieved, or until EPA makes a further determination that it has become
technically impracticable to achieve those criteria.
After the ROD was signed in 1990, EPA determined that the ROD did not
properly address several metals which had been listed as Constituents of
Concern in Table 6-1 of the Appendix to the ROD. Upon further review of
the sampling data gathered during the RI, EPA likewise determined that
metals contamination at the Site may have been prematurely dismissed
from consideration during the Remedial Investigation/Feasibility Study
(RI/FS) process. As a result, EPA had two primary concerns: (1) whether
metals contamination in ground waters at the Site exceed MCLs and/or
other criteria established by EPA for the protection of ground water;
and (2) whether the concentrations of metals in the Site soils and waste
materials result in unacceptable risk to human health based upon
standard exposure scenarios.
By means of an ESD issued on September 10, 1991, EPA notified the public
of these concerns and the steps that would be taken to properly address
them. Those steps consisted of: (1) the establishment of remedial
criteria for ground waters at the Site for six (6) metals, arsenic,
beryllium, cadmium, chromium, lead and thallium; (2) a program of
sampling and analysis for the same six metals in Site soils in order to
determine the extent, if any, of threat to human health or the
environment posed by metals in Site soils; (3) a similar program of
sampling and analysis for the same six metals for Site ground waters;
and (4) a determination as to what additional remedial technologies, if
any, will be necessary to address metals-contaminated soils, waste
materials, and ground
5
water.
5.0
Description of Significant Differences
5.1.
Metals Contamination in Site Soils and Ground Water
In February, 1993, SII submitted reports of sampling and analyses for
metals in surficial soils and ground waters at the Site. The sampling
and analyses were conducted in accordance with work plans prepared by
SII and submitted to EPA for review and approval. One aspect of the
approved work plans was that ground-water samples would be obtained by
more appropriate sampling techniques than those used during the RI. The
sampling techniques used in the more recent efforts were such that the
amount of suspended solids in the samples was kept to a minimum.
Suspended solids in samples taken from ground-water monitoring wells can
contribute to artificially high results when analyzed for metals
content. Another aspect of the approved sampling and analysis program
was that should these improved sampling techniques indicate that
ground-water was not contaminated to unacceptably high levels with
metals, no subsurface sampling for metals would be required.
The results of these sampling and analysis programs are summarized in
Appendix B. At the six satellite sites, out of 798 ground-water samples
for metals content, only three samples exceeded any established
ground-water protection standard identified in the September 1991 ESD.
All three of these exceedances were for one contaminant, lead, and one
of the three was in a background well at one of the satellite sites. The
other two were in one downgradient well at another satellite site; other
samples from that same well were found to be contaminated at levels
below the ground-water protection standard for lead. At the Plant site,
out of 450 ground-water samples analyzed, only five samples were
contaminated at levels which exceeded ground-water protection standards.
Of these, three were found to be contaminated at unacceptably high
levels for lead, one was for chromium and one for thallium. Again, in
each case the well found to be contaminated at such levels was found in
at least one other sampling event not to be contaminated.
In sampling of surficial soils, similar results were obtained. At the
six satellite sites, only one of 522 samples analyzed for metals content
was contaminated to a level that would constitute an unacceptable level
of risk to human health under standard residential exposure assumptions.
This sample was likewise found to be contaminated with lead, and was
obtained from the Welborn site. Surficial soils at the Plant site were
not submitted to an evaluation based upon residential exposure scenarios
due to the low likelihood of such exposure occurring either in the
interim before remediation takes place or thereafter.
In
addition,
the
surficial
soil
results
were
subjected
to
a
6
statistical evaluation wherein the results of analysis of samples taken
from affected areas of the six satellite sites were compared to
background levels. This evaluation demonstrated that there was no
statistically significant difference between the levels of contamination
found in the affected areas of the site and background levels of metals
in the surficial soils. These findings indicate that the soils overlying
the six satellite disposal sites are essentially the same as
naturally-occurring soils in the surrounding areas, suggesting that
waste materials disposed of in these satellite disposal sites were
covered with at least a thin layer of native soils.
Based upon these results, EPA has reached the following determinations:
a.
Ground-waters at all seven parcels of property which comprise the
Site are not significantly contaminated with metals. Only 0.4% of
the ground-water samples analyzed from the satellite sites (3 out
of 798 samples) and 1.1% of ground-water samples from the Plant
site (5 out of 450 samples) exceeded ground-water protection
standards identified in the September 1991 ESD. In each case, the
exceedance occurred in either a background well or in a well that
was found to be uncontaminated in at least one other sampling
event. As a result, EPA has determined that ground-water
remediation based upon metals contamination will not be performed
at any of the seven parcels that comprise the overall Site.
Continued monitoring for metals contamination in ground water will
be part of the operation and maintenance activities at the Site so
that long-term compliance with metals criteria can be evaluated.
b.
The level of contamination by metals in surficial soils at the six
satellite sites is not significantly different than the levels
found for the same metals in background surficial soil samples. As
a result, surficial soil remediation based solely upon metals
criteria will not be performed at the six satellite sites.
c.
Metals in surficial soils at the six satellite sites do not pose an
unacceptable level of risk to human health. The analytical results
for surficial soils were compared to benchmark concentrations that
would result in a Hazard Index of 1.0 under standard residential
exposure scenarios. In all cases, with one exception out of over
500 analyses, the concentrations found in surficial soils were
below the benchmark corresponding to a Hazard Index of 1.0. This
determination further supports EPA’s determination not to perform
any remediation of surficial soils at the satellite sites based
solely upon metals criteria.
d.
Since
ground-waters
at
the
Site
are
not
contaminated to
7
unacceptably high levels, subsurface evaluation for metals
contamination of the seven parcels that comprise the Site will not
be performed. Remediation of subsurface soils for metals
contamination would only be appropriate if subsurface metals
contamination was found to be contributing to unacceptably high
levels of ground-water contamination. Accordingly, no subsurface
remediation criteria for the six metals identified in the September
1991 ESD will be established.
5.2.
Ground-Water
Thallium
Remediation
Criteria
for
Beryllium and
The previous ESD for this Site, dated September 10, 1991, revised the
ROD by adding ground-water remediation criteria for six metals. Two of
those metals were beryllium and thallium. The remediation criteria for
both of these contaminants were established at 1 ppb. These criteria
were based upon the available toxicological data regarding potential
health effects resulting from exposure to these two metals.
At that time, EPA had not promulgated Maximum Contaminant Level Goals
(MCLGs) or Maximum Contaminant Levels (MCLs), for these two metals.
MCLGs are criteria established under the authority of the Safe Drinking
Water Act (SDWA) which are based solely on protection of human health,
without consideration of technical or economic feasibility. They are not
enforceable as drinking water standards for public water supplies. MCLs
are established under the authority of the SDWA as standards for
drinking water quality applicable to public water supply systems. MCLs
are established to be protective of human health, taking into account
the technical and economic feasibility of achieving compliance with the
MCL.
The National Contingency Plan (NCP) contains requirements for the
remediation of ground waters at Superfund sites, and these requirements
include the use of MCLGs and MCLs as remediation criteria. In 40 CFR
Part 300.430(e), the NCP requires the use of MCLGs, when available, as
remediation criteria, except when the MCLG is set at zero, when the MCLG
is relevant and appropriate to the circumstances of the release. When
the MCLG is zero, or where the MCLG is otherwise not relevant and
appropriate to the circumstances of the release, the MCL is to be used
as the remediation criterion.
On July 17, 1992, EPA promulgated final MCLGs and MCLs for beryllium and
thallium. The MCLGs for beryllium and thallium were set at 4 ppb and 0.5
ppb, respectively. The MCL for beryllium was likewise set at 4 ppb, and
the MCL for thallium was set at 2 ppb. Since the MCLG and the MCL for
beryllium are both 4 ppb, this concentration is set as the remediation
criteria for this contaminant in ground water at the Site.
8
For thallium, EPA promulgated an MCL that is greater than the MCLG, even
though the MCLG is not zero. Generally, if the MCLG is not zero, the
MCLG and the MCL are set at the same concentration, as in the case of
beryllium. In the case of thallium, however, the MCLG of 0.5 ppb is
below the Practical Quantification Limit (PQL) for this contaminant. In
other words, the MCLG concentration is less than the level at which
thallium can be detected and quantified with consistent precision and
accuracy by available analytical techniques. As such, using the MCLG as
a ground-water remediation criterion is not appropriate to the
circumstances of the releases from this Site, since it is not
technically
feasible
to
measure
compliance
with
such
a
low
concentration. Since the use of the MCLG is not appropriate, this ESD
modifies the existing ROD by setting the MCL of 2 ppb as the
ground-water remediation criterion for thallium.
The use of the MCL of 2 ppb for thallium remains protective of human
health. In the July 17, 1992, Federal Register promulgation of the MCL
for thallium, EPA states:
(T)he final PQL and MCL for thallium is being set...at 0.002
mg/l....The MCL for thallium is limited by the sensitivity of
available analytical methods (i.e., it is being set at the
PQL)....However, the Agency has concluded that the promulgated MCL
is adequately protective of human health because the MCLG includes
a large cumulative safety factor of 3,000. Thus, EPA believes that
the health risks of exceeding the MCLG up to the MCL are minimal.
(FR Volume 57, No. 138, p. 31815)
EPA has therefore determined that the ground-water remediation criteria
for beryllium and thallium should be revised. The revised remediation
criteria are 4 ppb for beryllium and 2 ppb for thallium. These criteria
correspond to the final MCLs promulgated by EPA for these contaminants.
5.3.
Waiver of TSCA Storage Requirements
Remedial actions to be undertaken at the Sangamo Weston Superfund Site
include the transport of waste materials and PCB-contaminated soils from
the six uncontrolled satellite disposal sites and storage of those
materials at a controlled location, the Plant site, until such time as
the LTTD treatment technology can be tested, constructed and placed in
operation. EPA had previously determined that TSCA regulations for the
storage of wastes contaminated with PCBs were applicable to this
remedial action.
Sampling of the waste material conducted as part of the remedial design
process has shown that the waste materials to be transported contain
PCBs in excess of 50 parts per million (ppm), the concentration subject
to regulation under the authority of the Toxic Substances Control Act
(TSCA). These findings render applicable TSCA regulations governing the
storage and disposal of
9
these materials. They are therefore ARARs for the remedial action
selected by the ROD.
After consideration of these regulations as they would affect the
implementation of the selected remedy, EPA has determined that these
regulations should be waived in accordance with the requirements of 40
CFR 300.430(f)(1)(ii)(C). The waiver is determined to be appropriate on
the basis of the fact that this storage is an interim measure that is
part of an overall remedial action that will, when fully implemented,
comply with all applicable or relevant and appropriate requirements
(ARARs); and that compliance with these ARARs would result in greater
risk to health and the environment than would result should they be
waived. For example, compliance with the TSCA requirement for
construction of an engineered storage facility would result in a
substantial delay in removing contaminated soils and waste materials
from the six satellite sites. During this delay, releases of
contaminants from the satellite would continue, along with continued
exposure to those contaminants by human and environmental receptors.
It is intended that the contaminated soils and waste materials from the
satellite sites will be stockpiled on the plant site in locations that
are already similarly contaminated and which will be included in the
overall site remediation. Placing the excavated materials from the
satellite sites on contaminated areas at the plant that are likewise
scheduled for eventual excavation and treatment will prevent additional
impacts associated with any potential migration of contaminants that
might occur if the materials were stockpiled in uncontaminated areas.
Measures will be taken to minimize run-on/runoff of precipitation and
infiltration of any leachate to ground water, but those measures would
necessarily be of a temporary nature. These measures will include an
earthen berm around the storage area to prevent storm water run-on and
run-off; a top liner of synthetic material covering the stockpiled soils
and waste; a system whereby the liner is anchored into the berm to
insure that the stockpile remains covered; and weights (for example,
sand bags) placed on the liner to prevent displacement by high winds.
A significant period of time may elapse between the time that the
material from the six satellite sites is excavated and transported to
the Plant site, and the time when treatment of soils and waste materials
by LTTD will commence. This is due to the need for treatability studies
to be conducted on the various LTTD treatment units that are
commercially available, the time necessary to complete design studies,
and the time necessary for the PRPs and their technical consultants to
prepare specifications and enter into contracts with a vendor for the
chosen remedial technology. This period of time could conceivably be as
much as two to three years after the material from the satellite sites
could be excavated and transported. During this period, the excavated
materials will be stored in a controlled access area within the
10
boundaries of the Sangamo Plant site.
5.2.1.
ARARs to be Waived
The primary regulations recommended for waiver are those related to the
storage for disposal of TSCA regulated wastes. Since the proposed
interim action will involve only storage of these materials, the final
fate of which will be treatment and disposal in a manner consistent with
all identified ARARs, there is no need to waive any ARARs directly
related to treatment or disposal, such as the TSCA regulations governing
the disposal of PCB contaminated wastes.
The regulations governing the storage for disposal of PCBs and PCB
wastes are found at 40 CFR Part 761, Subpart D. The storage regulations
are contained in Section 761.65. The storage requirements for PCBs and
PCB Items are presented in detail in Sections 761.65(b)(1)(i-v) and
761.65(c). It has been determined that the requirements of Sections
761.65(b)(1)(i-iv) and 761.65(c) should be waived.
Section 761.65(b)(1)(i) requires adequate roof and walls to prevent rain
water from reaching stored PCBs and PCB Items.
Section 761.65(b)(1)(ii) requires an adequate floor with continuous six
inch high curbing. Minimum requirements for the volume encompassed by
the floor area and height of curbing are also specified.
Section 761.65(b)(1)(iii) requires that the curbed area contain no
valves, drains joints or other openings that would permit liquids to
escape from the curbed area.
Section 761.65(b)(1)(iv) requires that floors and curbing be constructed
of continuous smooth impervious materials that minimize penetration of
PCBs.
Section 761.65(b)(1)(v) requires that the storage facility not be
located within a 100-year floodplain. Since the potential storage
locations at the plant site are all above the 100-year flood elevation,
this section need not be waived.
Section 761.65(c) allows PCB Items to be stored on a temporary basis
without meeting the structural requirements of Section 761.65(b)
described above. PCB Items are defined as any PCB Article, PCB Article
Container, PCB Container, or PCB Equipment, that contains or has (as) a
part of it any PCB or PCBs. This section limits the storage of these PCB
Items to no more than thirty (30) days. Since the waste material at the
satellite sites contains “off-spec” PCB capacitors, and perhaps other
PCB Items, this ARAR will also have to be waived in order for the
storage of
11
PCB Items contained in the satellite site materials to exceed thirty
days.
Waivers of the requirements for a TSCA waste storage facility, which
amount in essence to construction of a permanent structure with a roof,
walls and carefully constructed floor, are necessary in order to allow
the temporary storage of contaminated wastes and soils from the
satellite sites. The nature of the remedial action at Sangamo Operable
Unit 1 is that it will be a one-time operation, as opposed to a
continuing process. Construction of an engineered storage structure for
the contaminated soils and waste materials will result in significant
delay in the excavation and removal of these materials from the six
satellite sites. Appropriate waivers exist (as discussed below) that
allow the remedy to proceed without this unnecessary delay. In addition,
the temporary measures described above will be implemented in order to
minimize migration of contaminants from the temporary storage facility.
Region IV TSCA program personnel concur in the recommendation that these
waivers be granted.
5.2.2.
Basis of Waiver
The regulations that comprise the National Contingency Plan (NCP) are
found at 40 CFR Part 300. The NCP was published in final form in the
Federal Register (FR) Volume 55, No. 46, dated March 8, 1990.
In
Section 300.430(f)(ii)(C), six criteria are provided under which ARARs
for remedial actions can be waived. In addition, guidance as to the
applicability of these six criteria is provided in the preamble to the
proposed NCP regulations, published in the FR Volume 53, No. 245, dated
December 21, 1988.
The recommendation that the TSCA storage regulations cited above should
be waived is based upon the waiver criteria found in Sections
300.430(f)(ii)(C)(1) and 300.430(f)(ii)(C)(2), which are, respectively,
that the proposed action is an interim measure and will become part of
a total remedial action that attains all ARARs, and that compliance with
the TSCA storage ARARS will result in greater risk to human health and
the environment than would result under the proposed action. These two
criteria apply to the recommended waiver for all TSCA ARARs cited above.
A. Section 300.430(f)(ii)(C)(1); Interim Measures
The excavation of contaminated soils and waste materials from the
satellite sites and subsequent storage of these materials at the plant
site is an interim measure, i.e,. part of an overall remedy that will
when completed in its entirety attain all ARARs. The remedy selected in
the ROD includes eventual treatment of all contaminated soils and wastes
by low temperature thermal desorption (LTTD). The excavated material
from the satellite sites will eventually be subjected to LTTD, along
with similarly contaminated
12
materials from the Plant site itself. No permanent storage of PCBcontaminated soils or wastes will occur, and no additional storage of
such materials will occur once the remedy is complete (i.e., the storage
of contaminated materials will be a one-time event, rather than a
recurring event).
The interim storage will be necessary so that treatability studies,
full-scale design and system start-up activities can take place for the
implementation of the selected remedy. These measures are in turn
necessary so that the Agency can be assured of adequate performance of
the selected treatment technology and so that the PRPs can identify and
select a suitable technology vendor. This process is expected to take at
least two years, and may take as much as three years. Additional delays
could result should the selected soil treatment technology (LTTD) prove
to be incapable of achieving the performance criteria set forth in the
ROD, necessitating a change in the treatment technology, and an
amendment to the ROD.
The materials excavated from the satellite sites will be stockpiled in
areas that are themselves more heavily contaminated than the excavated
and stored soils and wastes. These highly contaminated areas on the
plant site are likewise slated for excavation and treatment by LTTD, so
that stockpiling the satellite site materials on top of the contaminated
plant site areas will have no appreciable effect on environmental
conditions. Any leachate that may be generated by infiltrating rainfall
will be addressed by the ground-water portions of the overall remedy,
and sufficient controls will be placed on the stockpile to insure that
any stormwater run-on/runoff and wind-blown dispersion will be minimized
and kept on-site.
The construction of an engineered storage facility that complies fully
with the technical criteria set forth in the TSCA regulations does not
appear to be warranted for a one-time, relatively short-term stockpiling
operation that is an interim component of an overall remedial action. An
engineered storage facility at the Sangamo plant site would never be
used again for the storage of TSCA-regulated wastes, the purpose for
which it would originally be designed.
In the preamble to the proposed NCP, a situation analogous to the one at
the Sangamo site is presented as an example of an appropriate use of the
interim measures waiver:
For example, the selected remedy at a site may include excavation
and treatment of the source. However, the treatment method may
require treatability testing or time for set-up or construction.
During this time, an interim measure involving stabilization of the
source, such as by use of a cap, may be appropriate. In such a
circumstance, the interim measure waiver would allow the temporary
stabilization actions
13
to constitute the initial components of a phased remedial response;
these actions would not be required to attain landfill closure
ARARs because the response would not be complete. (FR Vol. 53, No.
245, for December 21, 1988, p. 51439)
This discussion describes essentially the same circumstances as those
found at the Sangamo site; the difference is only that at Sangamo the
proposal is to use temporary storage, rather than stabilization, as the
interim measure, and that the ARARs to be waived are the TSCA storage
regulations rather than the RCRA landfill requirements. This example is
a clear indication that the use of the interim measures waiver is an
appropriate course of action for the proposed remediation at the Sangamo
site.
Based upon the interim nature of early soil removal from the satellite
site, therefore, a waiver of TSCA storage ARARs is included as part of
this ESD.
b.
Section 300.430(f)(ii)(C)(2); Greater Risk to Health and the
Environment.
The contaminated soils and materials at the six satellite sites
comprising a portion of the overall Sangamo Operable Unit 1 Site are
currently in an entirely uncontrolled setting. With the exception of the
Breazeale site, there are no engineered controls in place to limit the
migration of contaminants from the satellite disposal sites into
environmental media, such as ground waters, surface waters, subsurface
soils, etc. There is also essentially no control over access to the
disposal sites, except that exercised by the individual landowners. The
PRP, Schlumberger Industries, Inc., does not own the properties on which
the satellite sites are located, and therefore cannot exercise such
control over public access to the six satellite sites as they can to the
contaminated areas on the Plant site itself.
EPA has not required SII to provide access control over the satellite
sites because the contamination at the surface of each site does not
pose an unacceptable level of risk to occasional occupants or
trespassers on the sites. (Please refer to the Baseline Risk Assessment
in the Remedial Investigation report for further discussion and to the
results of metals analyses discussed above.) The primary source
materials, i.e., the PCB-contaminated wastes and soils, are in the
subsurface, and persons who might be on-site for short periods of time
are not exposed to this highly contaminated PCB source material.
This does
disturbed
treatment
possible
not insure, however, that the satellite sites may not be
at some time between the present and the time when the
system will become operational. Should this occur, it is
that the highly contaminated subsurface materials will
14
become exposed, creating a situation where greater risks to public
health would result. It should also be recognized that, even though the
risks posed by the satellite sites via contact with surface soils are
not currently outside the acceptable risk range, some risk due to
incidental contact is present. Persons who come into contact with the
surface soils under the present conditions will be subjected to an
increased incremental risk. Even though this risk may be minimal, some
finite increase in risk to public health exists under site conditions.
Rapid and early removal of the satellite site materials to the
controlled environment of the plant site will eliminate these risks.
In addition, releases of contaminants from the satellite sites into the
environment will continue to occur during the interim between the
present and whenever the satellite site soils and waste materials are
removed. These releases consist of runoff of contaminated soils into
nearby streams, leaching of contaminants into ground waters, and uptake
of site contaminants into biological systems (eg., bioaccumulation
and/or biomagnification). The sooner that the contamination in the
satellite sites is placed into a controlled environment at the plant
site, the sooner these releases will cease to occur. Expedited removal
of the contaminated materials from the satellite sites will not only
limit or minimize the mass of contaminants released into the
environment, but will also render the other site-related remedial
actions, such as ground-water remediation at some of the satellite
sites, more efficient and cost-effective.
Obviously, then, any delays in removing the satellite site materials
from their present, exposed state to the proposed storage location at
the plant site will result in increased exposure of the public to site
contaminants and continued and ongoing releases of contaminants into
various environmental media and biological systems. Full compliance with
the TSCA storage ARARs cited above will require a lengthy process of
design, contracting and construction of an engineered storage facility.
This process conceivably could take two to three years, whereas if these
ARARs are waived, excavation and transport of the satellite site
materials could be accomplished as early as late summer, 1993. While it
is not possible to quantify the reduction of risk that might be achieved
without knowing the delay that would result from full compliance with
these ARARs, and while it is reasonable to assume that this risk
reduction would be minor in absolute terms, it is clear that greater
risk to health and the environment will occur the longer that the
satellite sites remain in their current status.
Release of contaminants will continue while the materials are stockpiled
in temporary storage locations at the plant site, but control measures
will be implemented to minimize and control these releases. Release to
ground waters will be controlled by overall ground-water remedial
actions mandated in the ROD for the plant
15
site disposal areas. Run-on and runoff controls will be implemented for
the stockpile. All potential public exposure to contaminated soils and
wastes will be eliminated by placing the materials in a controlled
access area, within the bounds of the Sangamo industrial facility at the
Plant site. By these means, both releases and exposure are reduced
and/or eliminated, reducing risks to human health and the environment.
Therefore, based on the increased risks to human health and the
environment that will result from the delays incurred from full
compliance with TSCA storage ARARs, this ESD includes a waiver of those
storage requirements as ARARs for the remedial action.
6.0
Support Agency Comments
South Carolina Department of Health and Environmental Control (SCDHEC)
has reviewed this ESD and concurs in its contents.
7.0
Statutory Determinations
The modifications made to the ROD by this ESD are designed to determine
a remedy at the Site that will be protective of human health and the
environment, and will comply with Federal and State requirements that
are either applicable or relevant and appropriate, or alternatively to
provide waivers of those requirements in accordance with the provisions
of the NCP.
This ESD fulfills EPA’s commitment made in the ESD dated September 10,
1991, to determine if any additional criteria for metals are necessary,
and to choose any additional remedial technologies for metals as
appropriate, based upon the results of the additional sampling and
analysis program described in that ESD. EPA has determined that the
completed additional sampling and analysis program indicate that such
additional criteria and technologies are unnecessary to protect human
health and the environment at this Site. A 30-day public comment period
will be included as part of this ESD, and a responsiveness summary
prepared for any comments received during that period.
Any comments on this ESD should be submitted in writing to one of the
following persons:
Cynthia Peurifoy, Community Relations Coordinator
SC Section, North Superfund Remedial Branch
U.S. Environmental Protection Agency, Region IV
345 Courtland Street, NE
Atlanta, Georgia
30365
or,
16
R. Bernie Hayes, Remedial Project Manager
SC Section, North Superfund Remedial Branch
U.S. Environmental Protection Agency, Region IV
345 Courtland Street, NE
Atlanta, Georgia
30365
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE HARTWELL
PCB CONTAMINATION
Site Information:
Address:
SANGAMO WESTON, INC./TWELVE-MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION
PICKENS, SC
EPA ID:
EPA Region:
SCD003354412
04
Site Name:
Site Alias Name(s):
SANGAMO/TWELVE-MILE/HARTWELL PCB
SANGAMO WESTON-PICKENS PLANT
HAYWOOD RESERVOIR
MIDWAY LANDFILL
CROSS ROADS CHURCH
BREZEAL PROPERTY
WELLBORN PROPERTY
MAW BRIDGE ROAD
NIX, ERNEST PROPERTY
SANGAMO ELECTRIC
SANGAMO PROPERTY
SANGAMO WESTON/TWELVE-MILE/HARTWELL PCB
Record of Decision (ROD):
ROD Date:
Operable Unit:
ROD ID:
06/28/1994
02
EPA/ROD/R04-94/178
Media:
soil, water, aquatic biota
Contaminant:
PCBs
Abstract:
Please note that the text in this document summarizes the Record of
Decision for the purposes of facilitating searching and retrieving key
text on the ROD. It is not the officially approved abstract drafted by
the EPA Regional offices. Once EPA Headquarters receives the
official abstract, this text will be replaced.
The 730-acre Sangamo Weston/Twelve Mile Creek/Lake Hartwell
site is located in Pickens County, South Carolina. The site is zoned
for industrial use and is currently owned by Schlumberger Industries,
Inc. (as a result of a 1989 merger with Sangama Weston.) The site
was used for capacitor manufacturing from 1955 to the present. The
plant used a variety of dielectric fluids in its manufacturing
processes, including ones containing PCBs. Waste disposal practices
included land-burial of off-specification capacitors and wastewater
treatment sludge on the plant site and at six satellite disposal areas.
PCBs were also discharged with effluent directly into Town Creek,
which is a tributary of Twelve-Mile Creek. Twelve Mile Creek is a
major tributary of Lake Hartwell. Between 1955 and 1977,
approximately 400,000 lb. of PCBs were discharged into Town
Creek. An unspecified amount was also buried in six off site disposal
areas. The use of PCBs was terminated in 1977.
South Carolina Dept. of Health and Environmental Control
(SCHECD) studied the site in 1976 and found widespread PCB
contamination. A health advisory was issued in 1976 that warned
against eating fish in the Seneca River Arm of Lake Hartwell and in
Twelve Mile Creek. The site was proposed for inclusion in the NPL
in 1987 and finalized in February 1990. EPA lead the RI/FS
activities that were initiated in September 1990. The site was divided
into two OUs; OU 1 covering soil and OU2 covering the surface
water, sediment and bioaccumulation. The Final FS report was
released in April 1994.
This ROD addresses OU2 which discusses PCB contamination in
sediment and aquatic biota. The objective of the remedy is to reduce
risks associated with exposure to contaminated fish. Institutional
controls will be the primary remedy at this site.
Remedy:
The selected remedial action for this site includes continuing the
existing fish consumption advisory; implementing public education
programs; continuing monitoring of aquatic biota and sediment; and
regulation of Twelve Mile Creek Impoundments to facilitate burial of
contaminated sediment.
Text:
Full-text ROD document follows on next page.
EPA/ROD/R04-94/178
1994
EPA Superfund
Record of Decision:
SANGAMO WESTON, INC./TWELVE-MILE
CREEK/LAKE HARTWELL PCB CONTAMINATION
EPA ID: SCD003354412
OU 02
PICKENS, SC
06/28/1994
Text:
FINAL RECORD OF DECISION
for the
Sangamo Weston/Twelvemile Creek/Lake Hartwell
PCB Contamination Superfund Site - Operable Unit Two
Pickens, Pickens County, South Carolina
June 1994
Record of Decision Declaration
SITE NAME AND LOCATION
Sangamo Weston/Twelvemile Creek/Lake Hartwell PCB Contamination
Superfund Site - Operable Unit Two
Pickens, Pickens County, South Carolina
STATEMENT OF BASIS AND PURPOSE
This decision document presents the selected remedial action
for the Sangamo Weston/Twelvemile Creek/Lake Hartwell PCB
Contamination Superfund Site - Operable Unit Two ("Sangamo OU2")
in Pickens County, South Carolina, which was chosen in accordance
with CERCLA, as amended by SARA, and, to the extent practicable,
the National Contingency Plan. This decision is based on the
Administrative Record for the Site.
The State of South Carolina concurs with the selected
remedy.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from
this Site, if not addressed by implementing the response action
selected in this ROD, may present an imminent and substantial
endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE REMEDY
This Operable Unit is the final action of two Operable Units
for the Site. Operable Unit One addressed the land-based source
areas which included the Sangamo Weston Plant and six satellite
disposal areas. This action, Operable Unit Two, addresses the
sediment, surface water, and biological migration pathways
downstream from the source areas. This action addresses the
primary PCB human exposure pathway by mitigating the consumption
of PCB contaminated fish harvested from Lake Hartwell.
This major components of the selected remedy include:
Continuation of the existing fish consumption advisory on
Lake Hartwell;
Public education program designed to increase awareness of
advisory and methods to prepare/cook fish to reduce quantity
of contaminants consumed;
Continued monitoring of aquatic biota and sediment to
support continuance and/or justify modifications to existing
fish advisory; and
Regulation of Twelvemile Creek Impoundments that will
facilitate burial of contaminated sediment while mitigating
adverse impacts to Lake Hartwell water quality.
STATUTORY DETERMINATIONS
The selected remedy is protective of human health and the
environment, complies with federal and state requirements that
are legally applicable or relevant and appropriate to the
remedial action, and is cost-effective. This remedy utilizes
permanent solutions and alternative treatment technologies to the
maximun extent practicable. This remedy does not satisfy the
preference for treatment as a principal element based upon the
excessive costs associated with removal, treatment and disposal
of approximately 4.7 million cubic yards of PCB contaminated
sediment spread out over approximately 730 acres.
Because this remedy will result in hazardous substances
remaining onsite above health-based levels, a review will be
conducted no less often than every five years after commencement
of remedial action to ensure that the remedy continues to provide
adequate protection of human health and the environment.
_________________________
John H. Hankinson, Jr.
Regional Administrator
EPA - Region IV
___________
Date
TABLE OF CONTENTS
SECTION
PAGE
1.0
Site Name, Location, and Description.......................1
2.0
Site History and Enforcement Activities....................1
3.0
Highlights of Community Participation......................6
4.0
Scope and Role of Response Action..........................7
5.0 Summary of Site Characteristics............................8
5.1 Summary of Physical Characteristics...................8
5.1.1
Surface Features............................8
5.1.2
Surface Water Hydrology....................10
5.1.2.1
Surface Water Hydrology of Twelvemile
Creek Watershed............................11
5.1.2.2
Surface Water Hydrology of Lake Hartwell...13
5.1.3
Meteorology................................14
5.1.4
Demographics...............................15
5.2 Sediment Investigation Summary.......................16
5.2.1
Phase I Investigation......................17
5.2.2
Phase II Investigation.....................18
5.2.3
Field Screening-Modified Spittler Method...18
5.2.4
Nature and Extent of Contamination.........19
5.2.5
Other Contaminants in Sediment.............24
5.2.6
Summary of Surface Water Investigations....28
5.3 Biological Investigation Summary.....................28
5.3.1
Twelvemile Creek Watershed Investigations..29
5.3.2
Lake Hartwell Investigations...............33
5.3.3
Assessment of Resource Use.................38
5.4 Contaminant Fate and Transport.......................40
5.4.1
Future Sedimentation.......................40
5.4.2
Future Sediment and Water Quality Trends...43
5.4.3
Bioaccumulation and Future Fish
Concentrations.............................48
6.0 Summary of Site Risks.....................................50
6.1 Contaminants of Concern..............................50
6.2 Exposure Assessment..................................51
6.3 Toxicity Assessment..................................52
6.3.1
Carcinogenic Toxicity of PCBs..............52
6.3.2
Noncarcinogenic Toxicity of PCBs...........53
6.4 Risk Characterization................................53
6.5 Monte Carlo..........................................54
6.6 Ecological Risk Assessment...........................55
6.7 Uncertainty Assessment...............................56
6.8 Summary..............................................56
7.0 Description of Alternatives...............................66
7.1 Final Cleanup Goal for Sediment......................67
7.2 Final Cleanup Goal for Fish..........................68
7.3 Remedial Alternatives................................70
SECTION
8.0
PAGE
Summary of the Comparative Analysis of Alternatives.......82
8.1 Overall Protection of Human Health and
the Environmental....................................82
8.2 Compliance with ARARs................................83
8.3 Long-Term Effectiveness and Permanence...............84
8.4 Reduction of Toxicity, Mobility, and Volume..........85
8.5 Short-Term Effectiveness.............................86
8.6 Implementability.....................................88
8.7 Cost.................................................88
9.0 The Selected Remedy.......................................89
9.1 Continuation of Existing Health Advisory.............89
9.2 Public Education Program.............................89
9.3 Aquatic Biota and Sediment Monitoring................92
9.3.1
Aquatic Biota Monitoring...................92
9.3.2
Sediment Monitoring........................94
9.4 Regulation of Twelvemile Creek Impoundments..........94
9.5 Five-Year Reviews....................................99
9.6 Cost Estimate........................................99
10.0 Statutory Determinations.................................100
10.1 Protection of Human Health and the Environment......100
10.2 Compliance with ARARS...............................101
10.3 Cost Effectiveness..................................101
10.4 Utilization of Permanent Solutions and Alternative
Treatment Technologies to the Maximum Extent
Practicable.........................................101
10.5 Preference for Treatment as a Principal Element.....102
11.0 Documentation of Significant Changes.....................102
Appendix - Proposed Plan Fact Sheet
LIST OF TABLES
TABLE/TITLE
PAGE
5-1
Monthly Mean Temperature and Precipitation for
Clemson and Pickens, SC...................................15
6-1
PCB Exposure Point Concentrations in Shallow Sediment.....57
6-2
Exposure Point Concentrations in Fish.....................58
6-3
Exposure Parameters for Incidental Ingestion of and Dermal
Contact with Sediment (Current/Future Use Scenario).......60
6-4
Exposure Parameters for Ingestion of Fish by Adult
Recreational Fisherman (Current/Future Use Scenario)......61
6-5
Potential Direct Contact Risks Associated with PCBs
in Sediment...............................................62
6-6
Potential Health Risks Associated with Ingestion of Fish..64
8-1
Time to Achieve Protectiveness............................87
9-1
Sediment Sample Locations in Twelvemile Creek Watershed
and Arm of Lake Hartwell..................................98
9-2
Cost Estimate for EPA's Selected Remedy..................100
LIST OF FIGURES
FIGURE/TITLE
PAGE
1-1
Hartwell Lake and Watershed................................2
1-2
Sangamo OU2 Study Area.....................................3
2-1
Estimate of PCBs Received at the Sangamo Weston Plant......4
2-2
Estimate of PCBs Discharged Into Town Creek................5
5-1
Twelvemile Creek Drainage Basin............................9
5-2
Twelvemile Creek Profile..................................12
5-3
PCB Distribution for Grab Samples.........................25
5-4
Vertical Distribution of Mean PCB Concentration per
Transect Interval.........................................26
5-5
Vertical Distribution of Maximum PCB Concentration per
Transect Interval.........................................27
5-6
Twelvemile Creek Drainage Sampling Locations..............30
5-7
Lake Hartwell Fish Sampling Stations......................34
5-8
PCB Concentrations in Largemouth Bass Fillets (1990-93)...36
5-9
PCB Concentrations in Channel Catfish (1990-93)...........36
5-10 PCB Concentrations in Hybrid Bass Fillets (1990-93).......37
5-11 Simulated Bed Profile Twelvemile Creek Arm................41
5-12 Predicted Average Sediment Burial Rates...................42
5-13 Initial WASP4 Surface Sediment PCB Concentrations.........44
5-14 WASP4 Surface Sediment PCB Concentrations at 10 Years.....45
5-15 WASP4 Surface Sediment PCB Concentrations at 20 Years.....46
5-16 WASP4 Surface Sediment PCB Concentrations at 30 Years.....47
5-17 Initial and Predicted Concentrations of Selected Biota....49
7-1
FGETS Modeling Results for Selected PCB-Cleanup Goals.....69
7-2
Area to be Capped in Alternative 3A.......................74
7-3
Sediment Control Structure Location of Alternative 3B.....76
FIGURE/TITLE
PAGE
7-4
Sediment Control Structure/Axea to be Capped for
Alternative 3C............................................78
7-5
Confined Disposal Facility for Alternative 4..............80
9-1
Current Lake Hartwell Fish Advisory.......................90
9-2
Fish Sampling Stations in Lake Hartwell...................93
9-3
Corbicula Basket Sampling Locations in Twelvemile Creek...95
9-4
Sediment Sampling Stations in Lake Hartwell...............96
9-5
Sediment Sampling Stations in Twelvemile Creek............97
Final ROD-Sangamo OU2
June 1994
1.0
SITE NAME, LOCATION, AND DESCRIPTION
The Sangamo Weston/Twelvemile Creek/Lake Hartwell
Polychlorinated Biphenyl (PCB) Contamination Site - Operable Unit
Two (hereinafter referred to as "the Sangamo OU2 site" ) is
located in Pickens County, South Carolina. The Sangamo OU2 Site
comprises the sediment, surface water, and biological migration
routes downstream from the Sangamo Weston Plant and satellite
disposal areas that have site related PCB-contamination. The
Sangamo Weston Plant and satellite disposal areas constitute
Operable Unit one of the Site.
Lake Hartwell was constructed by the Savannah District U.S.
Army Corps of Engineers (COE) between 1955 and 1963 by damming
the Savannah, Seneca, and Tugaloo Rivers. Figure 1-1 provides an
illustration of the 56,000 acre Hartwell Reservoir located on the
Georgia-South Carolina border. The OU2 study area includes
approximately 40 stream miles of Twelvemile Creek and its
tributaries, the Twelvemile Creek Arm of Lake Hartwell, and
portions of the Keowee and Seneca River Arms of Lake Hartwell
down to the Route 37 (Rt. 37) bridge just south of Clemson, South
Carolina. Figure 1-2 provides an illustration of the Sangamo OU2
study area. The primary focus of OU2 is centered on this area;
however, samples were collected throughout Lake Hartwell during
the OU2 investigations including that portion of the reservoir
between Rt. 37 and Hartwell Dam.
2.0
SITE BISToRY AND ENPoRCEMENT ACTIVITIES
Sangamo Weston, Inc., owned and operated a capacitor
manufacturing plant in Pickens, South Carolina from 1955 to 1978,
near the headwaters of Lake Hartwell. The plant manufactured
several varieties of capacitors, including electrolytic, mica,
and power factor capacitors as well as potentiometers.
Schlumberger Industries, Inc. (SII) is the current owner of the
plant site, as a result of a merger with Sangamo Weston in 1989.
The plant used several varieties of dielectric fluids in its
manufacturing processes, including PCB-containing dielectric
fluids. PCBs reportedly enhanced the performance and durability
of the fluids. The PCBs used for this application were primarily
Aroclors 1242, 1254, and 1016. Waste disposal practices from the
Sangamo Plant included land-burial of off-specification
capacitors and wastewater treatment sludges on the plant site and
at the six satellite disposal areas. PCBs were also discharged
with effluent directly into Town Creek, which is a tributary of
Twelvemile Creek. Twelvemile Creek is a major tributary of Lake
Hartwell. The use of PCBs was terminated by Sangamo Weston in
1977 prior to an EPA ban on PCB use in January 1978.
Estimates of the type and quantities of PCBs received, used,
and discharged by Sangamo Weston were derived by reviewing
Monsanto Corporation shipping records, Sangamo Weston records,
interviews with Sangamo Weston employees, engineering and
analytical reports completed by firms under contract to Sangamo
Weston, and EPA documents. Figures 2-1 and 2-2 provide a
graphical illustration of the PCBs received at the Sangamo Plant
and an estimate of PCBs discharged to Town Creek, respectively.
<IMG SRC 0494178>
<IMG SRC 0494178A>
<IMG SRC 0494178B>
Final ROD-Sangamo OU2
June 1994
The average quantity of PCBs used by Sangamo Weston ranged from
700,000 to 2,000,000 lbs/yr from 1958 to 1977. Data indicate
that an estimated 3 percent of the quantities received and used
were discharged to Town Creek. This approach leads to an
estimated cumulative discharge of PCBs into Town Creek of over
400,000 lbs through 1977.
Historical surficial and core sediment studies of the
Twelvemile Creek watershed and Lake Hartwell were conducted by
several entities including the South Carolina Department of
Health and Environmental Control (SCDHEC), COE, EPA, RMT (for
Schlumberger), and several Clemson graduate students. These
studies were initiated in 1976 by SCDHEC and occurred
intermittently through the mid to late 1980s. PCB concentrations
in surficial sediments were highest from samples collected near
the plant's discharge point on Town Creek and generally decreased
with increasing distance downstream from the Sangamo Weston Plant
Site. PCB concentrations in sediment core samples were highest
in samples collected from the Twelvemile Creek Arm of Lake
Hartwell. PCB concentrations generally increased to maximum at a
depth of 10-30 cm.
In the mid-1970s, SCDHEC and EPA discovered that fish from
certain areas of Lake Hartwell were contaminated with PCBs at
levels above the U.S. Food and Drug Administration (FDA) safe
tolerance limit of 5 ppm (5 mg/kg). SCDHEC originally issued a
health advisory in 1976 that warned the public against eating
fish from the Seneca River Arm of Lake Hartwell north of State
Highway 24 (Hwy 24) and Twelvemile Creek (Figure 1-1). FDA
lowered the PCB tolerance level to 2 ppm (2 mg/kg) in 1984. As a
result, SCDHEC modified the original health advisory in 1985 to
state the following:
1)
All fish taken from the Seneca River Arm of Lake Hartwell
north of SC Hwy 24 and Twelvemile Creek should be released
and not eaten;
2)
All fish larger than three (3) lbs. taken from the remainder
of Lake Hartwell should be released and not eaten; and
3)
Fishing is not prohibited but SCDHEC advises that these fish
not be eaten due to the presence of elevated levels of PCBs.
Swimming, boating, and other related activities are not
restricted by this advisory.
This advisory remains in effect, and signs warning against
eating fish have been posted at the majority of the public boat
launch and recreation areas in South Carolina since 1987.
SCDHEC has conducted studies in Lake Hartwell since 1976 to
evaluate the levels of PCB contamination in fish. Their results
indicate that PCB concentrations in non-migratory fish (i.e
largemouth bass, catfish) collected within the Twelvemile Creek
embayment remain above the FDA 2 mg/kg tolerance level with no
apparent decrease over time. PCB concentrations in these nonmigratory species generally decreased with increasing distance
from the source area. However, migratory species (i.e.
Final ROD-Sangamo OU2
June 1994
hybrid/striped bass) collected at all stations in the lake had
elevated levels of PCBs which frequently exceeded the 2 mg/kg
tolerance level. There was no apparent decrease in migratory
fish tissue PCB concentrations over time.
In 1987, based upon the EPA Hazard Ranking System, SCDHEC
monitoring programs, and accompanying concerns of citizens in the
area, the Sangamo Site was proposed for inclusion on the National
Priorities List (NPL). The Sangamo Site was finalized on the NPL
in February 1990. As a result, EPA issued special notice to SII
in April 1990 for performance of a Remedial Investigation and
Feasibility Study (RI/FS). Since SII declined to conduct the
RI/FS, EPA assumed the lead-role in performing the RI/FS at the
Sangamo OU2 Site and formally initiated the process in September
1990. The RI/FS process for OU2 was divided into two separate
studies, a Sediment Investigation and Biological Investigation,
which were conducted concurrently. The Sediment Investigation
was conducted by the Oak Ridge, TN office of Bechtel
Environmental under the funding and direction of EPA. The
Biological Investigation was conducted by the Savannah District
of the U.S. Army COE, under funding and direction provided by
EPA.
3.0
HIGHLIGHTS OF COMMUNITY PARTICIPATION
EPA held an OU2 RI Kick-Off Public Meeting at the Liberty
(South Carolina) Senior High School Cafeteria on May 9, 1991 to
present the approach for the Phase I Sediment RI and overall
Biological Investigation strategy. On March 3, 1992, a public
meeting was held at the Ramada Inn in Clemson, SC to discuss the
Phase I Sediment Investigation results, planned approach for the
focused Phase II Sediment Investigation, and provide an update on
the Biological Investigations. The Final Remedial Investigation
Reports (Sediment and Biological components) and a summary fact
sheet were released to the public in May 1993. A public meeting
was held on June 3, 1993 at the Ramada Inn in Clemson to present
the findings from the completed investigations and the Baseline
Risk Assessment.
The Draft Feasibility Study Report and a summary fact sheet
were released to the public in February 1994 in an effort to
facilitate greater public involvement in the remedy selection
process at the Sangamo OU2 Site. On March 28, 1994, a public
forum was held at the Strom Thurmond Institute on the Clemson
University Campus to discuss the various remedial alternatives
under consideration in the Draft FS Report.
The Final FS Report, Proposed Plan Fact Sheet, and all other
site-specific documents EPA relied upon to develop the Proposed
Plan were arranged in an Administrative Record and released to
the public in April 1994. The Administrative Record was
maintained and available for public review at the EPA Records
Center in Region IV, and the following five information
repositories: The Village Library in Pickens, SC; Pickens County
Public Library in Easley, SC; R.M. Cooper Library at Clemson
University, SC; Hart County Library in Hartwell, GA; and the
Final ROD-Sangamo OU2
June 1994
Corps of Engineers Lake Hartwell Natural Resources Management
Center near the Dam in Hartwell, GA.
Concurrent with the public release of the Proposed Plan, a
notice of availability of the Administrative Record was published
in the Greenville News and Anderson Independent on April 11,
1994; the Athens Daily, Easley Progress, Hartwell Sun, and
Pickens Sentinel on April 13, 1994; and the Clemson Messenger
Journal Tribune on April 16, 1994. A public comment period was
held from April 11 through May 11, 1994. A Proposed Plan Public
Meeting was held on April 19, 1994 at the Ramada Inn in Clemson,
SC. At this meeting, representatives from EPA, the Savannah
District COE, and SCDHEC discussed the site conditions, the
remedial alternatives under consideration and presented the
rationale behind the preferred alternative. During this meeting,
a request for an extension to the public comment period was made.
As a result, the public comment period was extended until June
10, 1994. The notice of this extended public comment period was
published in the Greenville News on May 2, 1994.
A response to comments received during this 60-day public
comment period is included in the Responsiveness Summary, which
is attached to this Record of Decision (ROD) as Appendix B. This
decision document presents the selected remedial action for the
Sangamo OU2 Site in Pickens County, South Carolina, chosen in
accordance with CERCLA, as amended by SARA, and in accordance
with the National Contingency Plan. The decision for this Site
is based on materials in the Administrative Record and comments
received during the public comment period.
4.0
SCOPE AND ROLE OF RESPONSE ACTION
Due to the size and complexity of the Sangamo Site, and in
order to simplify the investigation and response activities, EPA
divided the Site into two discrete study areas known as Operable
Units (OUs). Operable Unit One (OU1) consists of the land-based
source areas, including the Sangamo Weston Plant Site and six
satellite disposal areas in Pickens County used for the disposal
of solid wastes containing PCBs (Figure 1-2). The six satellite
disposal areas are located in rural areas within a 3-mile radius
of Pickens and have the following designations: Breazeale, Cross
Roads, Dodgens, John Trotter, Nix and Welborn. EPA selected the
remedy for OU1 in a ROD signed on December 19, 1990. Under a
Consent Decree negotiated with EPA, Schlumberger initiated
remedial action at OU1 in November 1993. This included the
excavation of waste and PCB contaminated soils from the six
satellite disposal areas and transportation of the excavated
materials to temporary storage facilities at the former Sangamo
Plant Site. A treatment system will be built and tested at the
plant at which time the contaminated material will be treated by
means of low temperature thermal desorption. In addition,
groundwater recovery and treatment systems will be installed at
the plant site and at applicable satellite areas.
Operable Unit Two (OU2), the subject of this ROD, addresses
the PCB-contamination in the sediments and aquatic biota of the
study area (Figure 1-2). The exposures associated with ingestion
Final ROD-Sangamo OU2
June 1994
of fish contaminated with PCBs from all fish sampling stations in
Lake Hartwell exceeded EPA`s acceptable human health risk range.
OU2 represents the final response action EPA expects to implement
as part of its overall strategy in remediating the Sangamo Site.
This response action addresses the principal threat posed at the
Site which is ingestion of PCB-contaminated fish.
5.0
SUMMARY OF SITE CHARACTERISTICS
Due to the atypical size and complexity of the Sangamo OU2
Site, the Sediment and Biological Investigations generated an
immense and extensive data base. In the interest of brevity,
this information will not be reiterated in this ROD. This
section presents a brief, comprehensive overview of the Sangamo
OU2 Site characteristics as assessed during the Remedial
Investigation. The reader is referred to the Final Remedial
Investigation Report (May 1993), Volumes I and II and/or the
Final Biological Investigation Report (February 1994) for a more
detailed account of this subject matter.
5.1
SUMMARY OF PHYSICAL CHARACTERISTICS
This section presents information concerning the physical
characteristics of the study area including its surface features,
surface water hydrology, meteorology, and demographics.
5.1.1
Surface Features
The Sangamo OU2 study area generally consists of sloping to
moderately steep uplands that are dissected by a well-developed
drainage system. There are a number of small towns in the area
in addition to the city of Clemson. Outside of the towns and the
residential developments along the Hartwell lakeshore, the
countryside is predominantly rural. Much of the undeveloped area
is forested, but significant agricultural tracts can also be
found.
The northern portion of the Twelvemile Creek watershed is in
the foothills of the Blue Ridge Mountains, an area characterized
by steep, heavily forested slopes and ridges. Twelvemile Creek
originates near 1,920-ft-high Walnut Cove Mountain, in an
isolated area approximately 7 miles north-northeast of Pickens,
which includes first- and second-order streams with abundant
riffles (Figure 5-1).
The relief is somewhat lower in the vicinity of Pickens and
the OU1 source areas. In this portion of the watershed,
Twelvemile Creek occurs as a meandering, relatively slow-moving,
fourth-order stream with abundant pools, sand and gravel bars,
and broad floodplains that in some reaches exceed 1,000 ft.
However, approximately 1 mile south of Pickens, the stream valley
narrows and the creek has a large number of sharp bends. In this
area, Twelvemile Creek resembles a mountain stream with exposed
rocks, swift-moving water, and abundant riffles that in some
locations may be considered rapids. Floodplains are generally
absent as the creek valley narrows to widths of only 100 to 200
<IMG SRC 0494178C>
Final ROD-Sangamo OU2
June 1994
ft., bounded by moderate to steep slopes that are generally
covered with trees and other vegetation. Access to the creek is
difficult and generally limited to the few bridges in the area.
These conditions continue downstream (south) to the headwaters of
Hartwell Lake, just upstream of the Maw Bridge (Hwy 337 Bridge).
The Twelvemile Creek Arm of Lake Hartwell is characterized
by a narrow channel with steep, heavily vegetated shoreline with
only limited access. The waters in the upper portion of this arm
have been impounded and thus water velocities are greatly
reduced. There is a sharp bend in the lake near the Madden
Bridge, but otherwise the channel has a linear, northeastsouthwest trend. The lake becomes progressively wider
downstream, reflecting the widening of the former Twelvemile
Creek floodplain, and the number and size of inlet coves
increases. The lakeshore along the Twelvemile Creek Arm is
generally undeveloped due to the relief and development
restrictions imposed by the COE, which has classified much of the
western shoreline and the major inlet coves on the eastern
shoreline as a Protected Lakeshore Area. This designation does
not necessarily prohibit all development, but has served to
greatly limit the type and extent of development within this
portion of the lake.
In the downstream direction, past the Keowee River
confluence, into the Seneca River Arm and finally into Lake
Hartwell proper, the shoreline typically becomes more gradually
sloped and is more developed with less vegetative cover than the
shoreline of the Twelvemile Creek Arm. Relief around the main
portion of the lake is much lower, primarily due to the pool
elevation, which becomes progressively closer to the hilltops
toward the south.
Lake Hartwell was formed by the construction of Hartwell Dam
across the Savannah River approximately 7 miles below the point
where the Tugaloo and Seneca rivers converge to form the Savannah
River. Construction of the dam began in 1955 and was completed
in 1963. The dam is a concrete and earth structure that spans
18,000 ft across the Savannah River and rises 204 ft above the
riverbed at its highest point. At normal pool level, Hartwell
Lake extends for 49 miles up the Tugaloo River and 45 miles up
the Seneca River and its tributaries (i.e., Twelvemile Creek and
the Keowee River).
At a normal pool elevation of 660 ft. mean sea level (MSL),
the lake has an area of 56,000 acres and large expanses of open
water, particularly below the point where Twenty-six Mile Creek
meets the Seneca River. Because of the relief and large number
of coves, the lake has a shoreline of 962 miles. There are a
number of large arms in the main portion of the lake. The major
ones include the Tugaloo Arm, Twenty-six Mile Creek Arm, Coneross
Creek Arm, and Eighteen Mile Creek arm.
5.1.2
Surface Water Hydrology
The Sangamo OU2 study area is defined by hydrologic
features; therefore, the surface water hydrology is one of the
Final ROD-Sangamo OU2
June 1994
most important physical characteristics of the study area. This
section presents an overview of the hydrologic characteristics of
the Twelvemile Creek watershed and Lake Hartwell, which are the
principal hydrologic units in the study area.
5.1.2.1
Surface Water Hydrology of Twelvemile Creek Watershed
The Twelvemile Creek watershed has an area of 140-miý and
includes first-, second-, third- and fourth-order streams. The
tributaries to Twelvemile Creek are predominantly first- and
second-order streams. The major tributaries, Town Creek, Wolf
Creek, Rices Creek, and Golden Creek, are third-order streams.
Twelvemile Creek is a third order stream above the mouth of Town
Creek; below this point, Twelvemile Creek is a fourth-order
stream. Twelvemile Creek is the longest stream segment in the
watershed, which flows southward for approximately 24 miles until
reaching the headwaters of Hartwell Lake. Within this 24-mile
reach, approximately 80 tributaries flow into Twelvemile Creek.
The gradient of the Twelvemile Creek basin is represented by
the longitudinal profile shown in Figure 5-2. The profile
extends from the confluence of the Middle and North forks into
Hartwell Lake as far as the Rt. 37 Bridge (the downstream limit
of the study area in Hartwell Lake). From this figure, it can be
seen that the total elevation drop from the confluence of the
North and Middle forks to the headwaters of the lake is
approximately 200 ft, which over a distance of 17 miles amounts
to an average slope of 11.8 ft per mile.
The bulk of the stream flow is derived from runoff. Flow
data for Twelvemile Creek indicate an average daily flow of 198
cubic feet per second (cfs), with historical daily flow ranging
from 30 to 5360 cfs. Sediment in the creek is composed primarily
of sand and has a generally low total organic carbon content
(TOC), ranging from 0.1 to 3.6 percent. NPDES permit data
indicate that Twelvemile Creek receives discharges from sewage
treatment plants and a small number of industrial facilities.
These discharges average 1 to 2 million gallons per day. During
low flow periods, the permitted discharges may comprise 10-13
percent of the flow in the creek; during normal flows, the
discharges comprise less than 2 percent of the flow and become
negligible during high flow periods.
The three impoundments on the lower section of Twelvemile
Creek are all of masonry construction. The lowermost impoundment
(Woodside II) is the largest of the three, with an upper pool
elevation of 722 ft MSL and a lower pool elevation of 684 ft MSL
(difference of 38 ft). This impoundment was built in 1905. The
middle impoundment (Woodside I) is located in the community of
Cateechee and was rebuilt in 1937 after it failed in 1934. The
middle impoundment has an upper pool elevation of 760 ft MSL and
a lower pool elevation of 736 ft MSL (difference of 24 ft). Both
the lower and middle impoundments were constructed by Norris
Mills and are currently owned and operated by Consolidated Hydro
of Greenville, South Carolina. These two impoundments were
renovated in 1983-1985 and currently produce a combined
2.5 million kWh/yr. In 1984, up to 20 ft of sediments were
<IMG SRC 0494178D>
Final ROD-Sangamo OU2
June 1994
flushed from the pools behind the lower and middle impoundments.
In September 1993, an estimated 43,000 cubic yards of sediment
were flushed from behind the lowermost impoundment. Currently,
sediments are flushed from these pools approximately biannually.
The third, or uppermost, impoundment was built in 1926 and
is the smallest of the three impoundments, with an upper pool
elevation of 783 ft MSL and a lower pool elevation of 763 ft MSL
(difference of 20 ft). This upper impoundment was formerly used
for generation of hydroelectric power. The impoundment was
purchased by the Easley-Central Water District in 1962 and is
currently used as the intake point for the Easley-Central Water
Plant. Sediments are flushed from behind the upper impoundment
quarterly. Approximately 6 ft of sediments are flushed from
behind the impoundment during each flushing event.
Surface water in the Twelvemile Creek basin is currently
utilized for drinking water supply, fishing, and industrial uses.
Twelvemile Creek is classified as a Class B stream according to
South Carolina Regulations (Regulation 61-68, Water
Classifications and Standards). Under the regulations, Class B
waters are defined as being suitable for secondary-contact
recreation (fishing, boating, wading) and drinking water supply
(assuming conventional treatment methods are used) as well as
both agricultural and industrial uses.
5.1.2.2
Surface Water Hydrology of Lake Hartwell
The surface water hydrology of the Hartwell Lake reservoir
is different from that described for the Twelvemile Creek basin
because it is an impoundment with a drainage basin 2,088 miý.
Hartwell Lake is managed by the COE for flood control and
electric power generation, both of which are affected by the
storage capacity of the reservoir, which is 2,550,000 acre-feet
of water (equivalent to 830 billion gallons). Since its
construction, the reservoir has become one of the major
recreational lakes in the Southeast. Current management
practices therefore consider recreational benefits as well as
flood control and power generation.
The COE maintains a pool elevation of 660 ft MSL during the
recreation season (summer); in mid-October through mid-December
the lake level is dropped 4 ft to a level of 656 ft MSL. The lake
is drawn down in the fall in anticipation of the increased
rainfall that the area usually receives during the winter and
spring. The annual fluctuations in the lake commonly exceed 4
ft; peak elevations commonly occur in April or May. The lowest
recorded monthly average lake level of 643.3 ft MSL occurred in
December 1981.
Water flows in the Lake Hartwell system were characterized
by the inflow and outflow data provided by the COE. These data
consist of 30 years of daily inflow and outflow data collected
between 1962 and 1992. The average monthly inflow to the lake
for the period 1962-1992 ranged from a low of 2,693 cfs in
September to a high of 6,222 cfs in March. Average monthly
outflow from Hartwell Dam in the same period ranged from a low of
Final ROD-Sangamo OU2
June 1994
3,034 cfs in September to a high of 5,190 cfs in April. On a
yearly basis, the average monthly inflow to Hartwell Lake has
been 4,090 cfs; outflow has been 3,997 cfs. Given the reported
storage capacity of the reservoir (2,550,000 acre-feet or 830
billion gallons), the estimated hydraulic residence time in the
lake is 25 days.
Lake Hartwell is Class A surface water (South Carolina
regulations) suitable for primary contact recreation (swimming,
waterskiing), secondary contact recreation (fishing, boating,
wading), drinking water supply, and agricultural/industrial uses.
The lake currently receives a significant level of point and nonpoint source discharges. NPDES-permitted discharges include
industrial facilities, electric power generating stations, and
various sewage treatment plants. The permitted industrial
discharges include heavy metals, volatile organic compounds,
cyanide, phenol, oil and grease, and textile dyes. Permitted
discharges comprise only 18 million gallons per day
(approximately 200 cfs). Since the reservoir continues to be a
source of potable water for a number of communities, these
discharges apparently have not had an appreciable impact on water
quality in the lake.
5.1.3
Meteorology
Pickens County has a temperate climate characterized by mild
winters and relatively abundant rainfall. The National Weather
Service has two precipitation and temperature gauging stations in
the Twelvemile Creek area, one at Pickens and the other at
Clemson. Table 5-1 summarizes the monthly mean temperature and
precipitation for these two locations.
Generally the mean monthly temperature is higher in the
summer and winter months in Clemson while in the spring and fall
it is higher in Pickens. The average monthly precipitation for
the Pickens and Clemson stations ranges between 3.5 in. and
6.1 in. Annual precipitation in both Clemson and Pickens is more
or less evenly distributed throughout the year. The average
annual precipitation for Pickens from 1951-1992 was 56.04 in.
The maximum and minimum annual rainfall events occurred 1964 and
1981, respectively, when 78.46 in. and 33.40 in. were recorded.
In Clemson, the average annual precipitation from 1911-1992 was
53.23 in. The maximum and minimum annual rainfall events
occurred in 1936 and 1925, respectively, when 73.36 and 34.31 in.
of precipitation were recorded.
Free water surface evaporation data was obtained for the
study area from the Evaporation Atlas for the Contiguous 48
United States (NOAA 1982). These data indicate that annual
evaporation from Hartwell Lake should be in the range of 40 to 41
in. With annual precipitation in the area greater than 53 in.,
Hartwell Lake receives 12 to 13 in. of net precipitation per
year.
Final ROD-Sangamo OU2
June 1994
TABLE 5-1
Monthly Mean Temperature and Precipitation for Clemson and
Pickens, South Carolina1
Month
Clemson, SCý
Temp.
(øF)
Precipitation
(inches)
Pickens, SC3
Temp.
(øF)
Precipitation
(inches)
January
42.8
5.01
42.0
5.14
February
45.4
5.01
45.3
5.12
March
51.9
5.65
52.5
6.07
April
60.6
4.31
61.2
4.53
May
68.4
4.12
68.3
4.60
June
75.7
3.95
74.7
4.53
July
78.4
4.86
77.8
4.76
August
77.6
4.57
77.1
4.40
1
2
3
September
72.7
3.54
71.8
3.64
October
61.8
3.68
62.0
4.05
November
51.6
3.49
52.4
4.02
December
44.2
4.98
44.2
4.91
Data Source: National Climatic Data Center
Reporting Period 1911-1992
Reporting Period 1951-1992
5.1.4
Demographics
Demographics and land use in the Hartwell Lake area are
variable, with small towns and rural residential development in
the Twelvemile Creek watershed giving way to larger towns and
more concentrated development in the areas surrounding Hartwell
Lake. According to 1990 census data, approximately 356,000
people live in the six counties that border Hartwell Lake:
Anderson, Pickens, and Oconee counties in South Carolina; and
Hart, Franklin, and Stephens counties in Georgia. Of this total,
an estimated 297,000 people live in the South Carolina counties;
93,894 live in Pickens County alone.
The major community in the upper portion of the Twelvemile
Creek watershed is Pickens, which had an estimated population of
3,042 in 1990. Two communities are located along Twelvemile
Creek: Cateechee (estimated 1990 population of 158) and Norris
(estimated 1990 population of 884). The town of Clemson, with an
estimated 1990 population of 11,096, is the only large community
directly on the shoreline of the lake. Outside of the small
towns and communities, the majority of the Twelvemile Creek
Final ROD-Sangamo OU2
June 1994
watershed (and Pickens County in general) is undeveloped. Most of
the acreage bordering Twelvemile Creek and its tributaries is
either forested or cleared for agricultural purposes.
The entire Hartwell project, both land and water usage, is
managed by the COE Savannah District. Hartwell Dam was
constructed by the COE as part of a flood control and
hydroelectric power project. In addition to these primary uses,
Hartwell Lake has developed into one of the largest and most
popular recreational lakes in the southeastern U.S. According to
a 1989 COE survey, more than 15 million people visited the lake,
making it one of the three most visited COE lakes in the nation.
Data from a recreational area on Twelvemile Creek indicates that,
out of a total of 301,000 visitors, 125,787 visits were made for
fishing, 76,892 for boating, 30,310 for water skiing, and 28,139
for swimming.
Development along the shoreline of Lake Hartwell is at least
partially controlled through the COE Lakeshore Management Plan
(COE 1989). The COE controls 23,566 acres above the normal pool
elevation of 660 ft MSL. The COE acreage in effect establishes a
buffer zone of variable width around the entire shoreline. This
buffer zone enables the COE to restrict access, development, and
the types of activities permitted. These restrictions are
effected through a system of permits and land use allocations as
established in the Shoreline Management Plan. In order to
administer the permit program, the shoreline of Hartwell Lake was
allocated into four categories: Limited Development Areas, Public
Recreation Areas, Protected Shoreline Areas, and Prohibited
Access Areas.
Surface water supplies the bulk of potable water utilized by
the residents of Pickens County and surrounding areas. Currently
there are two active water intakes on Twelvemile Creek; these
intakes provide potable water supply to the Pickens Water Plant
and Easley-Central Water Plant. The Pickens Water Plant intake
point is located near the confluence of the Middle and north
Forks of Twelvemile Creek. Withdrawals from this intake enable
the Pickens Plant to supply 2 to 2.5 mgd of potable water to
approximately 4,000 residents in the Pickens area. The intake
for the Easley-Central Water Plant is located in the uppermost of
the three impoundments on Twelvemile Creek. According to the
Easley-Central Water Plant, withdrawals from this intake supply
an average of 1.2 mgd of potable water to approximately 1,100
residents in the plant's service area.
5.2
SEDIMENT INVESTIGATION SUMMARY
Field investigation activities for the sediment component of
the Sangamo OU2 RI were conducted in two seasonal sampling
events. The initial, Phase I event was conducted during July and
August 1991. The objectives of Phase I were to verify
extent-of-contamination data from previous investigations and
further characterize the magnitude and distribution of PCB
contamination in the Twelvemile Creek watershed and Hartwell
Lake. Results of Phase I sampling were used to define a focused
Final ROD-Sangamo OU2
June 1994
sampling program for the second, Phase II sampling event. Phase
II was conducted during April and May 1992. The objective of
Phase II was to address specific data gaps regarding the extent
of PCB contamination in sediments of the upper Hartwell Lake
reservoir (i.e., Seneca River, Keowee River, and Twelvemile Creek
Arms) and the Twelvemile Creek watershed.
5.2.1
Phase I Investigation
Phase I field sampling encompassed an area extending some 50
miles, from the Sangamo Weston Plant site and the satellite
disposal areas to the Hartwell Dam. A total of 480 samples,
exclusive of quality assurance/quality control (QA/QC) samples,
were collected during Phase I from Twelvemile Creek, its
tributaries, and Hartwell Lake. Phase I samples included 88
surface water, 341 sediment core, and 51 sediment grab samples,
at 50 locations throughout Lake Hartwell. An onsite field
screening method, the Modified Spittler Method (See Section
5.2.3), and offsite Contract Laboratory Program (CLP)
laboratories were used to analyze the samples.
A stainless steel ponar grab sampler was used for collecting
the surface sediment sample. The depth of sample collected by
the grab sampler was approximately 10 to 15 cm. A representative
sample from this surface zone was important to adequately
characterize the horizontal contamination in the biologically
active zone and to determine the quality of sediment that was
recently deposited. All 51 grab samples were analyzed by CLP
laboratories. Four of these samples were selected for fullscreen Target Compound List (TCL)/Target Analyte List (TCL)
analyses. Offsite analyses were also conducted for grain size,
TOC, and cation exchange capacity, all which are factors that
affect the mobility of PCBs and other contaminants.
Sediment core samples were recovered to a maximum depth of
50 cm to characterize the vertical distribution of PCBs in the
sediment. In shallow water areas, core samples were collected by
driving a stainless steel core tube into the sediment by hand.
In deep-water areas, a gravity corer with a stainless steel liner
and core catcher was used to collect the subsurface sample. In
both cases, sediment was extruded from the top of the core tube
at 5-cm intervals and placed in jars marked according to the
depth interval. All core samples were analyzed for total PCBs.
Split samples were collected from 19 percent of the sediment
cores analyzed onsite and sent for offsite PCB analyses at a CLP
laboratory. This was done to determine the correlation between
field and laboratory analytical results.
Surface water samples were collected at all 50 locations. A
near-surface water sample was collected at all stations by
dipping the mouth of the sample container just beneath the
surface of the water. Where water depths exceeded 4 to 6 ft, a
near-bottom sample was collected approximately 1 ft above the
sediment interface using a peristaltic pump and teflon tubing.
All 88 water samples were analyzed for PCBs and TOC at offsite
CLP laboratories. Samples from 4 stations received full scan
TCL/TAL analyses. Selected surface water samples were also
Final ROD-Sangamo OU2
June 1994
analyzed for the following water quality parameters: total
dissolved solids (TDS), total suspended solids (TSS), chloride,
flouride, sulfate, and nitrate-nitrite.
Given the large number of samples collected on the open
water of Hartwell Lake, the technical impracticality of
conducting an accurate location survey utilizing traditional
survey methods, and the importance of precise sample locations in
determining the nature and extent of contamination in OU2, sample
location coordinates (latitude/longitude) were determined
utilizing a hand-held Magellan Global Positioning System (GPS).
GPS is a network of 24 satellites orbiting the earth at an
altitude of 10,900 miles. The satellites and the hand-held
receivers both generate a continuous code which allows the
receiver to calculate how long it takes the signal to travel from
the satellite, and then to extrapolate the satellites's distance.
Once the hand-held receiver gets position information from three
satellites, position coordinates are determined by triangulation.
5.2.2
Phase II Investigation
During the Phase II study, a more extensive sampling program
was conducted in areas determined during the Phase I study to
have the highest PCB concentrations. The Phase II field sampling
effort focused on the Keowee River, Seneca River and Twelvemile
Creek Arms of Hartwell Lake as well as Twelvemile Creek itself.
Not including QA/QC samples, 744 samples consisting of 185
surface sediment, 550 sediment core, and 9 storm-event surface
water samples were collected and analyzed by field screening and
CLP analytical methods. Sample collection and location
techniques were as described under Section 5.2.1.
Twenty transects with a maximum of five sediment coring
stations per transect were established across the lake and creek
bed. The sediment core stations along each transect were
selected following a review of the bottom depth profile collected
with a bathymetric profiler. Sediment grab samples were then
collected between each transect location. Sediment was sampled
from a total of 374 locations during the Phase II study.
Composite surface water samples were collected from the following
bridges, which cross Twelvemile Creek and the upper reaches of
the Hartwell Lake reservoir: the Maw Bridge (Rt. 337), Madden
Bridge (Rt. 15), Hwy 133 Bridge, Hwy 93 Bridge, and Rt. 37
Bridge. Samples were collected from these stations following two
significant storm events to evaluate the potential for
resuspension of PCBs into the water column.
5.2.3
Field Screening - Modified Spittler Method
Both phases of the Sediment Investigation utilized the
Modified Spittler Method, a field screening analytical technique,
to significantly reduce cost and turnaround time on analyses.
Reduced turnaround time (approximately 24 hours) enabled sampling
teams to identify locations where additional sampling was
warranted and to evaluate data quality on a real time basis.
Final ROD-Sangamo OU2
June 1994
The Modified Spittler Method is an EPA-approved field
screening technique for quantifying total PCB concentrations in a
sediment/soil matrix. The technique employs a gas chromatogram
(GC) with an electron capture detector (ECD), and has
demonstrated reliability in the quantification of PCB
concentrations in excess of 1 ppm (mg/kg). The primary
difference in time and cost between the CLP procedure and
Spittler Method is incurred in the extraction procedure. Using
commonly available laboratory equipment, one analyst can extract
10 to 20 samples in less than 2 hours. The cost of GC/ECD
analysis using the Spittler Method is between $50 and $100,
compared to approximately $300 for conventional CLP analysis.
A total of 122 samples were analyzed for PCBs by both the
modified Spittler and CLP methods during Phase I and II. A
statistical comparison of the 67 Phase II samples analyzed by
both CLP and Spittler was performed by the EPA Environmental
Monitoring Systems Laboratory (EMSL) in Las Vegas, Nevada.
Twenty-eight of these samples were reported as "non-detect" by
both analytical methods. Of the remaining 39 samples, PCB
concentrations reported by Spittler were greater than those
reported by CLP for 35 samples, 3 samples analyzed by Spittler
were less than the concentration reported by CLP, and 1 sample
was not detected by Spittler, but was detected by CLP (i.e. false
negative).
In general, PCBs results obtained by field screening were
conservative. Ninety percent of the results were higher than
those obtained by the CLP method, and only one false negative was
reported. Only one result was an order of magnitude greater than
the CLP laboratory result. Although correlation coefficients
were low, the data sets were generally in agreement when the
factors affecting comparability are taken into consideration.
The major reasons for poor statistical correlation in results
were attributed to nonhomogeneity of the split samples and the
differences in PCB quantitation.
Based upon this comparison, the Modified Spittler Method was
found to detect PCBs as well as the CLP laboratory. It was
concluded that the Spittler Method produces data of Data Quality
objective (DQO) Level II/III when compared to DQO Level IV for
CLP analyses. However, the level of data quality generated by
this field screening technique allowed EPA to cost effectively
determine the nature and extent of PCB contamination in a study
area that encompassed approximately 40 stream miles and over
1,000 acres of open water.
5.2.4
Nature and Extent of PCB Contaminated Sediment
Previous investigations and the Sangamo OU2 RI have
delineated in detail the distribution and magnitude of PCB
contamination in sediment within the study area. Most of the
contaminated sediment lies within the upper portion of Hartwell
Lake, specifically the Twelvemile Creek Arm and Seneca River Arm
opposite the city of Clemson. Within the Twelvemile Creek
watershed, minor levels of PCB contamination have persisted in
Town Creek near the Sangamo Weston plant site and in the
Final ROD-Sangamo OU2
June 1994
impoundments associated with the 3 small dams on Twelvemile
Creek. Within Hartwell Lake, localized accumulations of
contaminated sediment have been detected as far downstream as the
dam, with concentrations generally decreasing with increasing
distance downstream from the Twelvemile Creek Arm.
Concentrations have been decreasing since the mid-1980's,
reflecting a decline in PCB input to the lake as well as the
burial and/or dilution of previously deposited sediment through
mixing with clean sediment.
A summary of the significant findings regarding PCB
contamination in sediment for eight subsections of the study area
is presented below. The sediment investigation results are also
graphically illustrated on Figures 5-3, 5-4, 5-5 at the end of
this section. Bridges and landmarks used in the description of
the study area subsections can be found on these figures or
Figure 5-1 and 1-2.
Upper Twelvemile Creek Watershed - This section includes
segments of the principal tributaries of Twelvemile Creek that
collect drainage or other discharges from the Sangamo Weston
Plant Site and the six satellite disposal areas. This section
also includes Hagood Reservoir and tributary reaches associated
with the Midway Dump and Easley-Pickens Landfill. Sampling
conducted for the RI and previous investigations supports the
following conclusions:
Sediment contamination in Twelvemile Creek was limited to
isolated occurrences between the mouth of Town Creek and the
upper (Easley-Central) impoundment; PCB concentrations were
typically <1 mg/kg.
PCB-contaminated sediments remain in Town Creek downstream
of the Sangamo Weston outfall; RI data show concentrations
as high as 6.5 mg/kg.
The OU1 satellite disposal areas represent insignificant
sources of PCB contamination based on the results of
sediment sampling from locations downstream of these areas.
Town Creek was confirmed as the only tributary contributing
PCBs to Twelvemile Creek, further substantiating earlier
conclusions that the Sangamo Weston Plant Site has been the
principal source of PCB contamination released into the
Twelvemile Creek watershed and Twelvemile Creek Arm of
Hartwell Lake.
Lower Twelvemile Creek Waterahed - This section includes the
three small impoundments and the lower reach of Twelvemile Creek
to the Lay Bridge (just south of the lowermost impoundment).
Sampling in the impounded waters and in close proximity
downstream of the 3 small dams in the lower reaches of Twelvemile
Creek indicate low levels of PCB contamination have persisted
and/or continue to accumulate in this area. Specific conclusions
include the following:
Final ROD-Sangamo OU2
June 1994
The upper impoundment had the lowest levels of PCB
contamination among the 3 impoundments; concentrations were
typically below detection limits or <0.5 mg/kg.
The middle (Woodside I) impoundment had only low levels of
PCB contamination (<1 mg/kg), most of which was detected in
core intervals below 10 cm.
More highly contaminated sediment has accumulated in the
lower (Woodside II) impoundment; most samples had <1 mg/kg
but concentrations ranged up to 6 mg/kg in core samples.
All 3 of the impoundments are flushed on a periodic basis to
remove sediment and the slightly contaminated sediment
detected in these impoundments will eventually be released
into the Twelvemile Creek Arm of Lake Hartwell.
Upper Twelvemile Creek Arm - This section begins at the Lay
Bridge and extends south, in a downstream direction, to Madden
Bridge (Route 15 Bridge). Historical and RI data indicate that
potentially significant quantities of PCB-contaminated sediment
have accumulated in the upper portion of the Twelvemile Creek Arm
of Hartwell Lake, particularly in the open water section
immediately above the Madden Bridge. Specific conclusions
include:
The most significant accumulations of PCB-contaminated
sediment coincided with depositional areas for fine-grained
materials; in the upper arm, these areas typically occurred
in proximity to the shoreline or in coves.
The uppermost portion of the arm, in the vicinity of Maw
Bridge, has only minor levels of contamination (1-2 mg/kg)
due to the higher water velocities and limited
sedimentation.
The open water area upstream of the Madden Bridge represents
the principal site for deposition of contaminated sediment
in the Twelvemile Creek arm; concentrations have ranged as
high as 153 mg/kg in historical samples and to a maximum of
61 mg/kg in the RI samples.
The magnitude of PCB contamination in the upper arm has
declined significantly since the mid-1980's, reflecting the
decreased input of PCBs to the lake and, in the open water
area, burial of the more highly contaminated sediment
through deposition of several feet of sediment with much
lower levels of contamination. This burial is consistent
with results from the HEC-6 sediment transport modeling
discussed in Section 5.4.
The vertical extent of contamination in the open water area
was not defined. Given that the source of PCB contamination
predated the impoundment of the creek and that releases
continued for many years thereafter, contaminated sediment
probably extends down to the original elevation of the land
surface (and former channel).
Final ROD-Sangamo OU2
June 1994
Middle Twelvemile Creek Arm - This section begins at Madden
Bridge and extends south to the Hwy 133 Bridge. A variable
distribution of low to moderate levels of contamination was
identified, with higher concentrations generally limited to
depositional areas having finer-grained sediment. Specific
conclusions include:
Sediment PCB concentrations in the middle portion of the arm
have varied over time, but since 1985 have consistently been
greater than 1 mg/kg and in most cases greater than 3 mg/kg.
RI data show surface sediments contaminated with 1-3 mg/kg
of PCBs and slightly higher concentrations in deeper
sediment from core samples.
The more highly contaminated sediment was encountered in
samples from depositional areas such as Moore Bend and the
open water area upstream of the Highway 133 Bridge.
PCB concentrations in samples collected from depositional
areas show a downward trend since 1988, indicating decreased
input of PCBs into the lake and that more highly
contaminated sediments have either been buried, resuspended
and transported away, or diluted through mixing with cleaner
sediments.
Alternating sequences of vertically increasing or decreasing
contamination observed in the majority of sediment cores
from the Twelvemile Creek arm complicate the interpretation
of the vertical extent of contamination. This vertical
extent was not defined in the middle segment of the arm.
Lower Twelvomile Creek Arm - This section begins at the Hwy 133
Bridge and extends south to the U.S. Hwy 123 Bridge adjacent to
Clemson. The lower portion of the Twelvemile Creek arm has also
been a depositional area for contaminated sediment, as evidenced
by the widespread PCB contamination in this area. A summary of
the major findings include:
RI data show PCB concentrations in surface sediments
generally in the range of 1-2 mg/kg; higher concentrations
were detected in core samples, with maximums in the 18-21
mg/kg range. Concentrations generally decreased with
increasing distance downstream but localized accumulations
of more highly contaminated material were identified.
The vertical limits of contamination generally occurred in
the upper 30-40 cm of sediment in most of the historical and
RI sediment cores.
The more highly contaminated sediment in the lower arm was
usually detected in samples collected from within or in
close proximity to the former submerged channel of
Twelvemile Creek.
A decline in sediment PCB concentrations was observed at the
mouth of Twelvemile Creek, reflecting the influence of the
Final ROD-Sangamo OU2
June 1994
Keowee River arm, which has a much higher average flow than
Twelvemile Creek.
PCB concentrations in the shallow sediment (0-15 cm) of the
lower arm have declined significantly, reflecting the
decreased input of PCBs and/or that the more highly
contaminated sediment detected in previous investigations is
getting buried by or diluted through mixing with cleaner
sediment.
The persistence of relatively high levels in deeper sediment
(down to 40 cm) supports conclusions based on the HEC-6
modeling that only limited amounts of sedimentation occur in
the lower portion of the Twelvemile Creek arm.
Keowee Arm - The Keowee Arm is a branch of Lake Hartwell that
meets the Twelvemile Creek Arm just north of Clemson. Historical
data and the Phase I/Phase II sampling results from the Keowee
River Arm indicate the following:
RI data have shown generally low levels of contamination (<2
mg/kg) in the lower part of the Keowee arm, most likely
related to hydrodynamic interactions with the Twelvemile
Creek or Seneca River arms.
Historical data included higher levels of contamination (6-7
mg/kg) in core samples collected from locations farther
upstream in the Keowee arm, possibly indicating an
additional PCB source in the upstream portion of the Keowee
arm. This contamination is probably not related to the
Twelvemile Creek source because of its occurrence several
miles upstream in the Keowee arm and because flow in the
Keowee is several times greater than flow in Twelvemile
Creek. Data were insufficient to characterize the magnitude
or determine the location of this source.
Seneca River Arm/Upper Section of Hartwell Lake - This section
begins at the Hwy 123 Bridge and extends south to the Route (Rt)
37 Bridge. PCBs were detected throughout this area as concluded
below:
Surficial sediments had contamination in the range of 1-2
mg/kg everywhere except the excavated channel opposite the
Clemson University diversion structures.
Deeper contamination was encountered in the former Seneca
River channel and the open water area just upstream from the
Highway 37/Southern Railroad embankment. Deposition of more
highly contaminated sediment near the Highway 37 embankment
was attributed to the hydrodynamic influences associated
with the constriction of the channel at this location.
Residual PCB contamination likely exists in the former
Seneca River channel located on the western edge of the
Clemson University campus, behind the diversion structures.
Final ROD-Sangamo OU2
June 1994
The vertical extent of contamination was defined and
generally limited to depths of 20-40 cm. A good correlation
between the depth of contamination in cores collected in
1988 and for the RI (in 1991-1992) indicate that only
limited sedimentation has occurred in this portion of the
lake during this 3 to 4-year period.
Maximum PCB concentrations in sediment core samples declined
from levels of 16 to 18 mg/kg in 1988 to concentrations of 5
to 11 mg/kg in 1991/1992; explanations for the decline, if
predicted low sedimentation rates are accurate, include
spatial variability in the distribution of contamination and
continued mixing of the vertical sediment profile.
Lake Hartwell Proper - This section includes the remainder of
Lake Hartwell, beginning at the Rt 37 Bridge and extending south
to the Hartwell dam. Historical sampling in this area indicate
that PCB contamination has migrated as far downstream as the
Hartwell dam. This was not confirmed during the RI. The
occurrence and magnitude of PCB contamination in Lake Hartwell
declined significantly downstream of the confluence of the Seneca
River Arm and Twenty-six Mile Creek, reflecting the input of
significant quantities of uncontaminated sediment from Twenty-six
Mile Creek and the various other tributaries. The majority of
widespread contamination in the lower part of the lake was
limited to concentrations below 1 mg/kg.
5.2.5
Other Contaminants in Sediment
A limited number of sediment grab and core samples were
collected for full-screen TCL/TAL analyses. No significant
contaminants other than PCBs were detected in these analyses.
Specific conclusions include:
No volatile organic contaminants were detected in any of the
samples other than an estimated concentration of acetone
(2200J æg/kg) in one duplicate sample.
A number of semivolatile organic compounds were detected in
one of the samples, mostly in low, estimate concentrations
that were not indicative of significant contamination.
Several unidentified semivolatile organic compounds were
reported in sediments at 4 sampling stations, ranging in
concentration from 2 mg/kg to 200 mg/kg. These compounds
were most likely petroleum hydrocarbons related to urban
run-off or boating discharges of fuel and oil.
Several pesticide compounds (DDE, DDD, and DDT) were also
detected, in low, estimated concentrations of 0.0024 to
0.053 mg/kg.
Metals analyses did not identify any sediment with elevated
concentrations of heavy metals; the following metals were
not detected: antimony, arsenic, cadmium, mercury, selenium,
and thorium.
<IMG SRC 0494178E>
<IMG SRC 0494178F>
<IMG SRC 0494178G>
Final ROD-Sangamo OU2
June 1994
5.2.6
Summary of Surface Water Investigations
Surface water quality investigations have focused on the presence
of PCBs in waters downstream of the Sangamo Weston Plant Site,
the OU1 offsite disposal areas, and/or the Midway dump and
Easley-Pickens landfill. Relevant conclusions from these
historical investigations and the RI studies include:
The most frequent and highest levels of PCB contamination
(1.7-20.3 æg/l) were detected in surface water samples
collected from locations downstream of the Sangamo Weston
outfall on Town Creek.
PCBs were either not detected or present in concentrations
<1 æg/l in surface water samples collected from drainage
ditches and tributaries associated with the OU1 offsite
disposal areas (Breazeale, Cross Roads, Dodgens, Trotter,
and Welborn disposal areas). These areas are apparently not
releasing appreciable levels of contamination to Twelvemile
Creek or its tributaries.
Based upon NPDES data, PCB concentrations in discharge from
the Sangamo Weston wastewater treatment plant outfall on
Town Creek during the mid-1970's averaged 13 æg/l and ranged
as high as 235 æg/l; NPDES monitoring data from this outfall
for 1992 reported PCB concentrations in the range 0.4 to
40.3 æg/l. This continued release of PCBs to Town Creek and
the downstream portions of OU2 are expected to terminate
once the OU1 remedial action at the Sangamo Weston plant
site has been completed.
PCBs were not detected in any of the surface water samples
collected for Phase I of the RI; detection limits for these
unfiltered samples ranged from 1.2 to 1.3 æg/l.
A limited number of these RI samples were also analyzed for
full TCL analyses; no volatile organics, extractable organic
compounds, pesticides or cyanide were detected, and
inorganic (metals) concentrations were not indicative of
contamination.
PCBs were not detected in any of the storm event samples
collected for Phase II of the RI; detection limits for these
unfiltered samples ranged from 1.2 to 1.3 æg/l.
5.3
BIOLOGICAL INVESTIGATION SUMMARY
Field activities for the Biological Investigations were
conducted by the COE in the Spring 1991, 1992, and 1993. The
field activities were divided into two individual study areas;
the Twelvemile Creek watershed and Lake Hartwell. The specific
methods employed and results from these two investigations are
summarized in the following sections.
The information gathered from the Biological Investigations
conducted in the Twelvemile Creek watershed further support the
Final ROD-Sangamo OU2
June 1994
conclusions made in the sediment component of the RI that: 1)
the Sangamo Plant Site is the primary source of PCB contamination
in Twelvemile Creek; and 2) the contribution of PCB contamination
in the Twelvemile Creek watershed from the six satellite disposal
areas is negligible. The aquatic biota in Twelvemile Creek
appear to have suffered from the influence of man's activities.
Although PCBs have likely contributed to these perturbations
producing cumulative effects, other factors have no doubt had an
additional impact on these animals at the population and
community levels.
Fish in Lake Hartwell continue to be contaminated with PCBs
often at levels that exceed the FDA safe tolerance limit of 2
mg/kg. PCBs appear to be the only pollutant of concern in Lake
Hartwell fish. The highest concentrations of PCBs in fish are
located in the Twelvemile Creek Arm. PCB concentrations in fish
species that are generally non-migratory decrease both downstream
and farther from the Twelvemile Creek Arm. Migratory fish
species have PCB concentrations that are similar throughout the
reservoir and are high enough to be a concern.
PCBs were detected at all levels of the food chain in both
the Twelvemile Creek watershed and Lake Hartwell. Pathways for
PCB uptake in aquatic biota of Lake Hartwell include ingestion
through the food chain and contact, most likely through the
gills. Exposure results from PCBs being adsorbed to sediments
and transported down Twelvemile Creek into Lake Hartwell.
The health of fish in Lake Hartwell does not appear to be
affected at the population level for fish that have PCB
concentrations at the current levels (around 5 mg/kg). However,
there is evidence that as concentrations increase to greater than
20 mg/kg fish health can be affected. Largemouth bass was the
target species used during these investigations. The sensitivity
or tolerance of other fish species to PCB contamination is not
known.
5.3.1
Twelvemile Creek Watershed Investigations
Field investigations in the Twelvemile Creek watershed were
conducted during Spring 1992 to: 1) determine the concentration
of PCBs in one primary sport fish species and one bottom feeding
species; 2) assess the condition of the fish community by
determining the Index of Biotic Integrity (IBI); 3) assess the
condition of the macroinvertebrate community by using Benthic
Rapid Bioassessment techniques; 4) assess fish health of
redbreast sunfish by using bioindicators and the Health
Assessment Index (HAI); 5) assess composition and fate of
harvest to determine public utilization by using a creel survey;
and 6) determine on-going PCB contamination due to transport of
drifting organic matter and bioaccumulation by a sediment
dwelling, filter feeding organism, the freshwater clam (Corbicula
fluminea).
Twelve sampling stations were established in Twelvemile
Creek and three uncontaminated tributaries. These sample
stations are shown in Figure 5-6. The length of each station was
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June 1994
from 0.3 to 0.5 miles to encompass gross habitat types and ensure
adequate sample size. Stations were permanently marked with
"Carsonite" markers located in the creek bank at the upper and
lower boundaries. All 12 stations were not involved in each subelement of the overall investigation (i.e. PCB tissue analysis,
IBI, HAI).
Twenty fish were collected for PCB contaminant analysis from
each of the stations in the Twelvemile Creek watershed and one
tributary reference site. Redbreast sunfish (Lepomis auritus)
were used as a sport fish species for assessment of human health
and environmental risk. Redbreast sunfish were chosen based on
abundance and likelihood of use by anglers. Ten redbreast were
collected per site. Ten northern hogsauckers (Hypentelium
nigricans) were collected per site to determine PCB
concentrations in a bottom feeding species to assess
environmental risk. Northern hogsuckers were selected based on
abundance and tropic level. Largemouth bass and bluegill were
substituted for redbreast sunfish at three stations.
Concentrations of PCBs in fish collected in the Twelvemile
Creek watershed were highest in Town Creek and Twelve Mile Creek.
Four of the 12 stations sampled had PCB values exceeding 2.0
mg/kg. Three of these stations (5, 8, and 12) were downstream
from the Sangamo Plant Site. Station 4, the other station having
high PCB values, was located just upstream from the confluence of
Town Creek and Twelvemile Creek and was probably affected by fish
migrating from both creeks. Stations upstream from station 4
could not be affected by migration due to a low head dam located
at the upper boundary of station 4. Mean PCB concentrations
ranged from a high of 12.5 mg/kg for northern hogsuckers in Town
Creek to a low of 0.88 mg/kg in redbreast sunfish in Twelvemile
Creek for stations downstream from the Sangamo Plant Site. The
remaining stations located in tributary streams or upstream from
the Sangamo Plant Site had lower PCB concentrations in fish than
those located downgradient from the plant site.
Several non-diagnostic studies which employed a metric/index
system were conducted to assess the health or condition of
individuals, populations and/or communities in the Twelvemile
Creek watershed. The benthic macroinvertebrate community of
Twelvemile Creek watershed was evaluated using EPA's rapid
bioassessment protocols. Samples were collected at a reference
site and the remaining sites shown on Figure 5-6. Eight of the
nine stations sampled in the Twelvemile Creek drainage were
classified as moderately impaired. Station 11, located upstream
of the Sangamo Plant site on Town Creek, was classified as
non-impaired and had high values for taxa richness and exhibited
an abundance of intolerant taxa. Sites immediately downstream of
the Sangamo facility exhibited evidence of greater impairment
than did upstream or tributary sites.
The Index of Biotic Integrity (IBI) was used to assess the
general health of the fish community in the Twelvemile Creek
watershed. The IBI index is based on a set of metrics determined
from species composition and abundance for a fish community.
These metrics focus on basic ecological characteristics of the
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June 1994
fish fauna and have been used effectively in stream monitoring
programs for the past decade. Nine stations in the Twelvemile
Creek watershed and three reference sites were sampled. The IBI
was effective for ranking the reference sites as expected based
on no identifiable impacts at station 1 (IBI 40), known impacts
of agricultural runoff at station 2 (IBI 30), and a known point
source discharge at station 3 (IBI 12). Therefore, it appeared
appropriate to use the IBI to assess the relative health of fish
populations in the Twelvemile Creek watershed with confidence.
The IBI scores indicated that all stations sampled have been
impaired to some degree. Most stations throughout the watershed
were classified as either "fair" or "good" indicating moderate
negative effects on the fish communities that could have resulted
from habitat degradation from man's activities. Only the two
reference stations 2 and 3 that were identified as having known
impacts and station 5, located in Twelve Mile Creek downstream
from Town Creek, were classified as "poor" or "very poor." The
IBI classification at station 5 ("poor") and a comparison of
relative health between sample stations and reference stations
indicated that station 5 has been severely impacted. Both
habitat degradation and water quality impacts including PCB
contamination likely contributed to this adverse impact.
Both the macroinvertebrate and fish communities have been
impaired throughout the Twelvemile Creek watershed. Assumably,
these impairments have resulted from PCB discharges, habitat
degradation, particularly siltation due to erosion from
development, siviculture and agriculture, and poor water quality
from both point and non-point discharges throughout the
watershed.
The Health Assessment Index (HAI) was employed to assess the
health of redbreast sunfish at selected stations in the
Twelvemile Creek drainage and a reference site. HAI is an
autopsy based index that uses divergence from the normal of
various organs, tissues and blood parameters to evaluate fish
health. The HAI scores for redbreast sunfish were variable
throughout the watershed ranging from 39.3 to 62.7. Station 12
located in Town Creek immediately downstream from the Sangamo
site had the lowest HAI score, 39.3, indicating healthy fish at
this site.
It is not evident from evaluating the HAI scores that the
health of redbreast sunfish has been effected by PCB
contamination. HAI scores were variable throughout the drainage.
However, scores in the range seen during this investigation were
not considered high. It is likely that health problems that
would manifest themselves to visual inspection through autopsy do
not occur in fish contaminated at the lower PCB concentrations
seen in redbreast sunfish in the Twelvemile Creek drainage.
Drift net samples were used to collect detritus (floating
organic matter) in Town Creek downstream of the Sangamo site and
in Twelvemile Creek at Lay Bridge. Additionally, cages of
"clean" Corbicula fluminea (fresh water clams) were placed at
Final ROD-Sangamo OU2
June 1994
these sites for 28 days to determine rates of bioaccumulation of
PCBs by analyzing the muscle tissue. Drift net samples of coarse
particulate matter collected from Town Creek, immediately
downstream of the Sangamo Plant Site had detectable PCB
concentrations ranging from 0.066 to 0.51 mg/kg. PCB
concentrations in corbicula collected at this station ranged from
0.75 to 0.88 mg/kg. Corbicula collected from the station
immediately downstream of the Lay Bridge had PCB concentrations
that ranged from 0.45 to 0.57 mg/kg. From these results, it can
be concluded, that even though PCBs have not been detected in
water samples collected from the study area, transport of PCBs
down Town Creek and Twelvemile Creek is occurring.
5.3.2
Lake Hartwell Investigations
Studies in Lake Hartwell were conducted during Spring 1991,
1992, and 1993 to: 1) determine the concentration of PCBs in
primary sport and forage fish species; 2) assess fish health of
largemouth bass using bioindicators and HAI; 3) determine PCB
concentrations in seston and macroinvertebrates; and 4) assess
composition and fate of harvest to determine public utilization
using a creel survey.
Fish species selected for Lake Hartwell contaminant analysis
included: 1) sport and/or commercial species, 2) fishes that
seasonally occupy different habitats or exhibit seasonal
migrations, and 3) primary forage species. Species selected for
collection and analysis were: largemouth bass, hybrid bass,
channel catfish, threadfin shad (Dorosoma petenense), gizzard
shad (Dorosoma cepedianum), blueback herring (Alosa aestivalis),
and bluegill (Lepomis macrochirus).
A total of 134, 144, and 144 fish were collected from six
locations throughout Lake Hartwell during spring 1991, 1992, and
1993, respectively. These six stations are illustrated on Figure
5-7 and were selected to represent a gradient of PCB
contamination in fish ranging from the most impacted (SV-107 in
the Twelvemile Creek embayment) to a background location (SV-641)
in the Tugaloo Arm. These fish were analyzed for PCB
concentrations in standard U.S. FDA fillets with skin on, descaled with rib cage (except for catfish where the skin was
removed). Additionally, the 60 largemouth bass collected in 1991
were analyzed for priority pollutants. Composite samples of
forage fish, including bluegill, threadfin shad, gizzard shad,
and blueback herring, were collected from SV-107 (highly
impacted), SV-532 (intermediate zone), and SV-641 (background).
PCB concentrations in fish have historically been highest in
the Twelvemile Creek Arm of Lake Hartwell (SV-107) and decrease
in a downstream direction. This is expected since PCBs enter
Lake Hartwell bound to sediments that are transported down
Twelvemile Creek, as discussed in Section 5.2 of this ROD.
Results of PCB analyses collected from 1990-1993 for largemouth
bass, channel catfish, and hybrid bass are graphically
illustrated on Figures 5-8, 5-9, and 5-10, respectively. These
years were comparable since analyses were completed in the same
manner. Although 4 years of data may be insufficient to justify
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June 1994
meaningful trend analysis, PCB levels decreased significantly in
largemouth bass at SV-107 (Figure 5-8). This trend was not
significant at other stations. As in past samples, PCB levels in
largemouth bass decreased in a downstream direction. PCB
concentrations in channel catfish have also decreased at stations
farther from the source in Twelvemile Creek (Figure 5-9).
However, there has been little change in the PCB concentrations
in channel catfish over the past 4 years
The distribution of PCB concentrations in hybrid bass
throughout the lake remains a concern. Hybrid bass collected
farther from the source in Twelvemile Creek have higher PCB
concentrations than other species, often exceeding the FDA
tolerance level of 2 mg/kg (Figure 5-10). This is thought to be
a result of their migratory behavior and is also seen in the
samples of walleye, another migratory species having high
concentrations of PCBs (mean 3.48 mg/kg) from SV-642 at Hartwell
Dam.
Contaminants other than PCBs were not identified at
concentrations of concern nor were they widely distributed.
A
comparison of the priority pollutants to the established USFDA
action levels showed that no chemical exceeded any of the safe
tolerance standards except PCBs. Priority pollutants having no
standards were compared to SCDHEC's fish tissue trend data base.
Out of 60 largemouth bass there were 17 different compounds
(mostly petroleum and organic solvents) that occurred only once
in a single fish and several others that occurred only twice.
There was no pattern of contamination and PCBs are considered the
only contaminant of concern.
Forage fish species had mean PCB concentrations ranging from
3.00 mg/kg in threadfin shad to 12.43 mg/kg in gizzard shad at
SV-107. PCB concentrations in forage fish decreased at stations
farther from the Twelvemile Creek Arm. This supports the
hypothesis that migratory species bioaccumulate PCBs while
located in the upper Seneca River rather than through the food
chain as forage species migrate out of the more heavily
contaminated area.
The effects of PCB contamination on fish health and
reproductive competence in Lake Hartwell were examined utilizing
the HAI, biological indicator analyses, and age and growth
analysis. Largemouth bass were the target fish species sampled.
Comparisons of fish health using the HAI as the indicator were
made among all six stations sampled in Lake Hartwell in 1992 and
1993. Differences in the HAI were seen between stations.
Station SV-107 consistently had the highest HAI score for each
year sampled. Station SV-106, the closest downstream station,
also had high HAI scores. During 1992, these two stations
exceeded 80 while stations farther from Twelvemile Creek ranged
from 42 to 65. Fish from Twelvemile Creek (SV-107) and Martins
Creek (SV-106) had the highest occurrence of fatty liver
conditions. Accumulation of fat in the liver can be associated
with exposure of fish to PCBs. The remaining stations had a
greater percentage of normal livers with little occurrence of
fatty livers. Although HAI scores only indicate the relative
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Final ROD-Sangamo OU2
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health of fish without indicating cause, decreases in the HAI
scores with distance from the source was consistent with declines
in PCB concentrations in fish at these stations.
Biomonitoring using biological indicators of fish health and
reproductive competence was conducted at both Twelvemile Creek
and Lake Hartwell study sites. The selected suite of
bioindicators measured in this investigation included, among
others, organ dysfunction, nutritional status, gonadal analyses,
detoxification enzymes, and concentrations of reproductive
steriods. The redbreast sunfish was the target species in the
Twelvemile Creek watershed, while largemouth bass was the target
species in Lake Hartwell. Bioindicator analyses conducted in
Twelvemile Creek indicated that PCB contamination probably
contributes, but is not the sole cause of impacts on fish health.
There was evidence of biochemical and physiological differences
between Lake Hartwell stations with largemouth bass collected
from SV-107 exhibiting abnormal responses to several
bioindicators. The most obvious physiological difference in
largemouth bass between stations related to the functions of the
liver. Additionally, age and growth analysis indicated that
largemouth bass from SV-107 had a slower growth rate and were
less plump having lower weights per unit of length.
Cages of clean corbicula were deployed for 28 days at two
locations in the Twelvemile Creek Arm of Lake Hartwell to
evaluate the uptake of PCBs by this filter feeding organism. The
two locations were established in the "goose-neck bend" area
between the Maw (Hwy 337) and Madden (Hwy 15) Bridges and near
the lower end of Twelvemile Creek Arm, just above the Keowee
River confluence. PCBs were detected in corbicula muscle tissue
at concentrations ranging from 0.48 mg/kg at the lower Twelvemile
Creek Arm station to 0.56 mg/kg at the goose-neck bend station.
Adult mayflies were also collected from the Twelvemile Creek Arm,
just above the Hwy 133 Bridge and were found to have 2.6 mg/kg of
PCBs.
5.3.3
Assessment of Resource Use
Public utilization of the fishery resources was assessed by
creel surveys on Twelvemile Creek and Lake Hartwell. Twelvemile
Creek was surveyed at major access points upstream to the
confluence of the Middle Fork and North Fork. Lake Hartwell was
divided into eight sampling areas that allowed analysis of angler
use relative to PCB concentrations in fish within each area.
Additionally, interviews provided data from which to evaluate the
economic importance of the resource. The interviews also
included questions to assess how fishermen used or consumed their
harvest and fisherman awareness of the health advisory. These
questions were the same for both the Lake Hartwell and the
Twelvemile Creek creel survey.
Angler use of Twelvemile Creek appeared to be minimal. Only
21 interviews were obtained during this investigation. Some
anglers were interviewed more than once indicating there may be a
small localized group of anglers that frequent Twelvemile Creek.
Most anglers interviewed were located at bridge crossings near
Final ROD-Sangamo OU2
June 1994
the confluence of Twelvemile Creek and Lake Hartwell. They were
encountered from March through August only. There was evidence
of some fishing in more upstream areas from the presence of the
types of trash that is customarily associated with bank
fishermen. However, anglers were not encountered at these
locations indicating low use.
Most anglers (66%) do consume fish caught in Twelvemile
Creek. Channel catfish and sunfish made up most of the harvest.
Consumption estimates for those anglers that indicated they ate
fish were higher for Twelvemile Creek (37 g/day) than for Lake
Hartwell (28 g/day). However, the total estimated harvest for
Twelvemile Creek in 1992 was only 116.2 kg (256 lbs.).
Public utilization of the fishery resources in Lake Hartwell
was also assessed by creel survey. A total of 415,839 fish were
caught in 728,489 angler-hours of effort. A total of 239,726
(58%) were released, while 176,112 fish weighing 115,320 kg
(253, 703 lbs.) were harvested. The top five species sought
included largemouth bass, anything, striped bass, hybrid bass,
and crappie. Largemouth bass and crappie comprised the largest
percentage by number of fish harvested, while largemouth bass and
hybrid bass comprised the largest percentage by weight.
The number of fish harvested was greatest in areas which
comprised the Twelvemile Creek, Keowee River, and Seneca River
Arms which encompass the most heavily contaminated portion of
Lake Hartwell and much of the area under the most extreme
advisory. Additionally, the Seneca River Arm area had the
highest harvest by weight. By weight, 29% of the largemouth
bass, 48% of the hybrid bass, and 66% of the striped bass
harvested from Lake Hartwell came from the Seneca River Arm.
Despite the advisory concerning fish consumption, anglers
continue to harvest the largest portion of fish from Lake
Hartwell from the areas most affected by PCB contamination.
Eighty-five percent of all anglers responding were aware of
the fish consumption advisory. Sixteen percent had stopped
eating fish because of the advisory. Sixty-seven percent of
anglers interviewed indicated they ate fish from Lake Hartwell.
The mean monthly per capita consumption for Lake Hartwell anglers
that eat fish was estimated to be 0.85 kg (1.86 lbs). The mean
monthly per capita consumption estimate for the Twelvemile Creek
Arm, the most contaminated area, was 0.9 kg (2 lbs) near the lake
average.
The health advisory on fish consumption appeared to
influence consumptive habits of less than one-fourth of the
anglers interviewed. Most anglers cited other reasons why they
had stopped eating fish caught from Lake Hartwell. Most anglers
indicated that they practiced catch-and-release, presumably for
sport reasons. Some anglers indicated that a stronger advisory,
a ban on fishing, seeing people get sick from eating fish and/or
documentation of increased contamination would affect their fish
consumption habits.
Final ROD-Sangamo OU2
June 1994
5.4
CONTAMINANT FATE AND TRANSPORT SUMMARY
An integral component of the Sangamo OU2 RI was to develop
predictions regarding the continued deposition, migration, and
accumulation of PCB contaminants in the sediment, water, and
aquatic biota of Lake Hartwell. These predictions were
accomplished through the use of specialized numerical-based
models that considered the environmental processes and
contaminant characteristics that control PCB migration and
accumulation as well as the intermedia transfer and degradation
of PCBs.
This comprehensive modeling effort focused on changes to an
approximate 10 mile reach of the Twelvemile Creek Arm of Lake
Hartwell over a 30-year period and consisted of: 1) future
sediment transport/deposition using the HEC-6 computer model,
"Scour and Deposition in Rivers and Reservoirs, Version 4.0",
which was developed by the Hydrologic Engineering Center of the
COE; 2) future PCB fate and transport using the "Water Quality
Analysis Simulation Program (WASP-4), Version 4.0" developed and
supported by EPA; and 3) future aquatic bioaccumulation modeling
using the "Food and Gill Exchange of Toxic Substances (FGETS),
Version 3.0" developed by EPA. The results of these modeling
efforts are summarized below.
5.4.1
Future Sedimentation
The objective of sediment transport simulation was to
determine rates at which presently contaminated sediments would
be buried by relatively clean sediments from tributary drainages
over the next 30 years. This simulation assumes that the
historic hydrologic flow regime and sediments loading to the
system remains unchanged. An overview of sedimentation regimes
within the Twelvemile Creek Arm and upper Seneca Arm is
summarized below. Figure 5-11 provides a bed profile of the
Twelvemile Creek Arm. Figure 5-12 provides an illustration of
the average sediment burial rates as predicted by the HEC-6
model.
The model identified three distinct sediment transport
regimes. The first regime extends from just below the Woodside
II impoundment (Transect T19) to a point approximately 2,400 ft
upstream of the Maw Bridge (Transect T16). This reach is
upstream of the backwater influence of the Hartwell impoundment
(normal pool elevation of 660 ft MSL) and, therefore, behaves as
a river. Energy gradients, bottom shear stresses, and turbulence
intensities are relatively large in this reach; sediment
transport potential is therefore high and sediments of all sizes,
sand included, are carried by the flow aa suspended sediment.
The HEC-6 results predict excess sediment transport potential,
resulting in a small amount of scour along this reach.
The second regime extends from upstream of the Maw Bridge to
just above the Hwy 133 bridge; this reach represents a zone of
transition from a high energy fluid environment (river) to a low
energy environment (lake). As the transition from river to lake
occurs, energy gradients, bottom shear stresses, and turbulence
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levels all decrease, resulting in high rates of sediment
deposition (1.43 to 13.12 cm/yr) as all of the sand and most of
the silt coming into the reservoir are deposited (clays remain as
suspended sediment and continue downstream). The model predicted
a 30-year accumulation of nearly 10 ft of sediment in some areas.
Sedimentation in this area results in the formation of a delta
that advances into the impoundment over time, moving the
headwater location further into the impoundment as well (See
Figure 5-11). With a continuous supply of sediment from the
watershed, this delta eventually will advance below Madden
Bridge.
The third regime extends from upstream of the Hwy 133 bridge
to the Hwy 37 bridge, which marks the downstream extent of the
system modeled. Hydraulically, this portion of the system
behaves as an impoundment with low-energy gradients and
turbulence levels. This quiescent environment favors sediment
deposition; however, only small deposition depths and burial
rates are predicted because most of the sand and silt load is
deposited upstream, and only slow-settling, clay-sized particles
are available for deposition downstream. Most of the clay
entering this reach is deposited, resulting in predicted
deposition depths ranging from 0 to 54 cm and average burial
rates of 0 to 1.8 cm/yr.
5.4.2
Future Sediment and Water Quality Trends
Future PCB fate and transport in the Twelvemile
Creek/Hartwell Lake system was modeled using the WASP4 code
developed by EPA. The modeling was conducted to predict the fate
and transport of PCBs in the Twelvemile Creek/Hartwell Lake
system over the next 30 years. This work was conducted to assist
in the extrapolation of PCB data collected in the present
investigation to future conditions. An overview and results of
the water quality modeling study are summarized below. Figures
5-13, 5-14, 5-15, and 5-16 provide predicted PCB concentrations
in surface sediment initially, at 10 years, 20 years, and 30
years, respectively.
Results from the WASP4 simulations reflect a relatively
complex cycling of PCBs through the system. Initially, PCB
concentrations are relatively high in upstream surface and bottom
sediment segments. Over time, clean sediment from the upstream
tributary is deposited over the contaminated sediments, which
results in burial and dilution of the contaminated sediments.
Because sediment resuspension and deposition can occur
simultaneously, some contaminated sediments from upstream
segments is resuspended in the water column, where advection and
dispersion transport them further into the impoundment. These
contaminated sediments are then redeposited. Because suspended
sediment concentrations decrease with increasing distance into
the impoundment, the rate at which redeposited sediments are
buried is much smaller than at points upstream where they
originated.
The net result of these transport processes is (1) a
significant reduction in PCB concentrations in the surface and
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bed sediments in the upper and middle portions of the system, and
(2) an increase in PCB concentrations in surface and bed
sediments near the lower end of the system. Surface and bottom
sediments upstream of the Hwy 133 bridge, which had initial PCB
concentrations ranging from 1,600 to 10,000 æg/L, are predicted
to decrease to near zero levels within the first 5 years. This
reduction in concentration is due to burial by clean sediments
derived from upstream reaches along with removal by sediment
resuspension.
In the middle reach of the system between the Hwy 133 bridge
and the Hwy 93 bridge, PCB concentrations also decrease over time
for the same reason but at a much slower rate. Initially,
concentrations in this middle reach ranged between 1,800 and
23,000 æg/L. The range is reduced to 400 to 8,000 æg/L after
5 years, 50 to 2,800 æg/L after 10 years, and 0 to 40 æg/L after
30 years. Surface and bottom sediments lying between the Hwy 93
bridge and the Hwy 37 bridge show PCB concentrations increase
over time. Initially, concentrations in these segments ranged
between 400 and 1,400 æg/L; after 30 years, concentrations in
these segments are predicted to range up to 8,800 æg/L. This
predicted concentration increase is attributed to hydrodynamic
influences associated with the Hwy 37 embankment.
5.4.3
Bioaccumulation and Future Fish Concentrations
Aquatic bioaccumulation modeling was conducted to predict
future PCB levels in the fish of the Twelvemile Creek/Hartwell
Lake system using the FGETS model. This work was conducted to
assess: (1) how PCB levels in fish would change over the next
30 years if the contaminated sediments were left unmanaged, and
(2) how long it would take for
FDA tolerance level of 2 mg/kg
of the aquatic bioaccumulation
below. Figure 5-17 provides a
levels to drop below the current
in several species. The results
modeling study are summarized
graphical summary of this effort.
FGETS is a time-dependent model that predicts whole-body
fish residues at specified points in time. The outputs of the
model are averaged residues for each year of the fish's life.
FGETS can predict chemical uptake by fish through two principal
pathways: (1) directly from water via respiration, and (2)
through consumption of contaminated food and sediments. For
hydrophobic organic chemicals, such as PCBs, the second pathway
is known to be the more significant one.
Application of the FGETS model requires the construction of
a conceptual model, which includes selection of a representative
food web. Three species of fish were chosen to be included in
the representative food web, based on the species present in
Hartwell Lake, the availability of data for calibration, and the
potential for human exposure. Largemouth bass was selected as
the top predator for the food web model, since it is the most
frequently harvested species and currently has the highest PCB
residues for game (harvest) fish. Gizzard shad and bluegill
sunfish were identified as the two most important forage fish for
Hartwell Lake largemouth bass. Plankton and benthos composed the
lower levels of the food web. Plankton and benthos were assumed
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Final ROD-Sangamo OU2
June 1994
to be in chemical equilibrium with the dissolved-phase PCB
concentrations of the water column and particulate-phase PCB
concentrations of the surficial sediments, respectively, as
predicted by the WASP4 water quality model.
Actual modeling consisted of a long-term simulation to
predict future PCB fish tissue concentrations over the next
30 years. Results show PCB concentrations in all components of
the aquatic bioaccumulation model decreased over the 30-year
simulation period (Figure 5-17). PCB concentrations in plankton
and benthos, assumed to be in chemical equilibrium with the water
column and surface sediments, showed a rapid rate of decline
consistent with the WASP4 predictions. In response to decreasing
water column and surface sediment PCB levels, concentrations in
fish declined as well. Mean concentrations in largemouth bass
fillets (10.75 mg/kg initially) declined to 5.16 mg/kg by year 5
and fell to 1.74 mg/kg and below the 2.0 mg/kg FDA tolerance
level by year 10 (year 2003).
Although the mean largemouth bass concentration fell below
the FDA limit by year 10, a longer period of time is required for
concentrations in older age classes to fall below the FDA limit.
PCB concentrations in 10-year-old fish, representing the highest
age class and largest fish in the model, required 12 years (year
2005) to fall below the 2.0 mg/kg FDA limit. By year 30, mean
concentrations in largemouth bass fillets are expected to be very
low, with a mean value of 0.025 mg/kg predicted.
6.0
SUMMARY OF SITE RISKS
CERCLA directs EPA to protect human health and the environment
from current and potential exposure to hazardous substances at
the Sangamo OU2 Site. The Baseline Risk Assessment provides the
basis for taking action and indicates contaminants and the
exposure pathways that need to be addressed by the Remedial
Action. It serves as an indication of what risks the Site poses
if no action were taken. A Baseline Risk Assessment was
conducted to evaluate the potential current and future human
health and ecological impacts associated with exposure to PCBs in
sediment and fish. This section of the ROD contains a summary of
the results of the Baseline Risk Assessment conducted for this
Site. Tables utilized and referenced in this discussion are
included at the end of this Section to facilitate the readability
of this Section.
6.1
CONTAMINANTS OF CONCERN
The Baseline Risk Assessment focused only on PCBs as the
chemical of potential concern. As described in Section 5.0,
full-screen analyses were conducted on a limited number of
sediment and fish tissue (biological) samples. These analyses
did not detect appreciable quantities of volatile organic
compounds (VOCs), semivolatile organic compounds (SVOCs),
pesticides, and/or inorganics (metals).
Final ROD-Sangamo OU2
June 1994
The human health exposure pathways that were quantitatively
evaluated under this Baseline Risk Assessment were as follows:
1)
Ingestion and dermal absorption of PCBs in shallow sediment
by a child and an adult at:
The upper section of Twelvemile Creek Arm,
The upper Twelvemile Creek Watershed,
The Hagood Reservoir, and
Immediately downgradient of the Sangamo Plant Site.
2)
Ingestion of PCB-contaminated fish by a recreational
fisherman.
Sediment data were divided into two overall categories in
order to best define exposure. These included sediment sample
locations which were 2.1 m (7 ft) or less below the water
surface, and sediment sample locations which were between 2.1 m
and 3 m (7-10 ft) below the water surface. As discussed
previously, the lake level fluctuates an average of 4 ft, hence
exposing additional sediment. The lower interval was developed
to evaluate this potential exposure. Table 6-1 summarizes the
information used to calculate sediment exposure point
concentrations at the four locations. Sediment data is from the
Phase I and Phase II Sediment Investigation.
The risks posed by the ingestion of PCB-contaminated fish
were evaluated at all six Lake Hartwell fish sampling locations
(SV-107, SV-106, SV-532, SV-535, SV-642, SV-641). These
locations are depicted on Figure 5-7 in Section 5.3 of this ROD.
In addition, risks posed by the ingestion of fish caught in the
Twelvemile Creek watershed, tributaries of the watershed, and a
background location were quantified. Risks were evaluated
separately by fish species and also for all species combined to
account for both individuals who may eat one specie exclusively
and individuals who consume all types of fish. Table 6-2
summarizes the information used to calculate fish tissue exposure
point concentrations at these locations. Fish tissue data are
from the 1991 and 1992 Biological Investigations prepared in
accordance with standard FDA fillet method (i.e. fillet including
rib cage and belly flap with skin on/scales off - except catfish
where skin is removed).
6.2
EXPOSURE ASSESSMENT
For purposes of this Baseline Risk Assessment, it was
assumed that in the future the Twelvemile Creek/Lake Hartwell
system will continue to exist in its present state. All exposure
pathways that are complete under the current land-use conditions
were also assumed to be potentially complete under the future
land-use scenario. The exposure pathways that were
quantitatively evaluated under the current/future use scenarios
are described in Section 6.1 of this ROD.
EPA employed a reasonable maximum exposure (RME) approach to
estimate the potential exposures and associated risks at the
Sangamo OU2 Site. The RME is the highest exposure that is
Final ROD-Sangamo OU2
June 1994
reasonably expected to occur at the Site.
The intent of the RME
is to estimate a conservative exposure case that is still within
the range of possible exposures. The calculation of risk posed
by exposures to PCBs requires the combination of exposure point
concentrations with assumptions regarding frequency, duration,
and magnitude of receptor contact. RME exposure point
concentrations for sediment and fish tissue are listed in Tables
6-1 and 6-2, respectively. The RME exposure parameter
assumptions for sediment and fish that were used to characterize
risk posed by PCBs are listed in Tables 6-3 and 6-4,
respectively. The exposure parameters for ingestion of fish were
derived from results the site-specific recreational angler survey
discussed in Section 5.3.
6.3
TOXICITY ASSESSMENT
For risk assessment purposes, individual chemicals are
separated into two categories of chemical toxicity depending on
whether they exhibit principally carcinogenic (cancer-causing) or
noncarcinogenic effects. The carcinogenic and noncarcinogenic
toxicity of PCBs are discussed below.
6.3.1
Carcinogenic Toxicity of PCBs
EPA assigns weight of evidence classifications to potential
carcinogens. Under this system, chemicals are classified as
follows:
Group A - Human Carcinogen: Sufficient evidence from human
epidemiological studies to support a causal association
between a chemical and cancer.
Group B1- Probable Human Carcinogen: Limited evidence from human
epidemiological studies of carcinogenicity to humans.
Group B2- Probable Human Carcinogen: Sufficient evidence of
carcinogenicity to animals.
Group C - Possible Human Carcinogen: Limited evidence of
carcinogenicity in animals and an absence of data on
humans.
Group D - Not Classified:
in animals.
Inadequate evidence of carcinogenicity
Group E - No Evidence of Carcinogenicity to Humans
PCBs are classified as a Class B2 carcinogen, which
indicates that there is sufficient evidence from tests on animals
to link exposure of PCBs with carcinogenic effects.
Slope factors (SFs) have been developed by EPA for
estimating excess lifetime cancer risks associated with exposure
to potentially carcinogenic contaminants. SFs, which are
expressed in units of (mg/kg-day)-1 or risk per milligram per
kilogram of dose, are multiplied by the estimated intake of a
potential carcinogen, in mg/kg-day, to provide an upper bound
Final ROD-Sangamo OU2
June 1994
estimate of the excess lifetime cancer risk associated with
exposure at that intake level. The term "upper-bound" reflects
the conservative estimate of the risks calculated from the SF.
Use of this approach makes underestimation of the actual cancer
risk highly unlikely. Slope factors are derived from the results
of human epidemiological studies or chronic animal bioassay data
to which mathematical extrapolation from high to low dose and
from animal to human dose has been applied, as well as statistics
to account for uncertainty (e.g. to account for the use of animal
data to predict effects on humans). A SF of 7.7 (mg/kg-day)-1 for
the PCB Aroclor 1260 was obtained fram the Integrated Risk
Information System (IRIS) for use in this Baseline Risk
Assessment.
6.3.2
Noncarcinogenic Toxicity of PCBs
Reference doses (RfDs) have been developed by EPA for
indicating the potential for adverse health effects from exposure
to the contaminants exhibiting noncarcinogenic effects. RfDs,
which are expressed in units of mg/kg-day, are estimates of daily
exposure levels for humans, including sensitive populations, that
are likely to be without risk of adverse effect. Estimated
intakes of contaminants from environmental media can be compared
to the RfD. RfDs are derived from human epidemiological and
animal studies to which uncertainty factors have been applied. A
chronic RfD of 7 X 10-5 mg/kg-day for the PCB Aroclor 1016 was
used in this Baseline Risk Assessment. This daily exposure
estimate has been documented in studies conducted on monkeys to
produce reproductive effects (reduced birth weights).
6.4
RISK CHARACTERIZATION
For carcinogens, risks are estimated as the incremental
probability of an individual developing cancer over a life-time
as a result of exposure to the contaminants of concern, in this
case PCBs. Excess life-time cancer risk is calculated from the
following equation:
Risk = CDI x SF
where:
Risk =
CDI
=
SF
=
a unitless probability (i.e. 2 x 10-5) of an
individual developing cancer.
chronic daily intake averaged over 70 years
(mg/kg-day).
slope factor, expressed as (mg/kg-day)-1.
These risks are probabilities that are generally expressed
in scientific notation (i.e. 1 x 10-6). An excess lifetime cancer
risk of 1 x 10-6 indicates that, as a reasonable maximum estimate,
an individual has a 1 in 1,000,000 chance of developing cancer as
a result of site-related exposure to a carcinogen over a 70 year
lifetime under the site-specific exposure conditions for the
site. EPA's generally acceptable risk range is 1 x 10-4 to 1 x
10-6.
Final ROD-Sangamo OU2
June 1994
The potential for noncarcinogenic effects is evaluated by
comparing an exposure level over a specified time period with a
reference dose derived for a similar exposure period. The ratio
of exposure to toxicity is called a Hazard Quotient (HQ). An
HQ<1 indicates that an individual's dose of a single contaminant
is less than the RfD, and that the toxic noncarcinogenic effects
from that chemical are unlikely. The Hazard Index (HI) is
generated by adding the HQs for all chemicals of concern that
affect the same target organ within a medium or across all media
to which a given population may reasonably be exposed. An HI<1
indicates that, based on the sum of all HQs from different
contaminants and exposure routes, toxic noncarcinogenic effects
from all contaminants are unlikely. The HQ is calculated as
follows:
Non-cancer HQ = CDI/RfD
where:
CDI =
RfD =
chronic daily intake
reference dose
CDI and RfD are expressed in the same units (mg/kg-day) and
represent the same exposure period.
The carcinogenic and noncarcinogenic risks associated with
direct contact with or incidental ingestion of PCB contaminated
sediment and ingestion of PCB-contaminated fish are summarized in
Tables 6-5 and 6-6, respectively. Adverse human health risks
resulting from direct contact or incidental ingestion with the
sediment are unlikely to occur, however, sediments are a
continuing source of contamination in the aquatic biota of the
study area. Exposures associated with the ingestion of fish
caught from all sampling stations resulted in unacceptable risks
ranging from 10-2 to 10-4. The highest cancer risk of 4 x 10-2 was
calculated for anglers exclusively consuming largemouth bass from
the Twelvemile Creek watershed. The highest cancer risk for
ingestion of all species combined, 1 x 10-2, was calculated for
the Twelvemile Creek Arm. The lake-wide risk associated with
ingestion of all species combined was 5 x 10-3.
6.5
MONTE CARLO
The human health risks presented under Section 6.4 are
referred to as the deterministic risks. That is, the resultant
risk is a single value for a single set of specific exposure
parameters. A refined approach to risk assessment can be
achieved by taking into account the probability distributions of
possible values for each of the exposure parameters rather than
relying on discrete parameter values. Such an approach was taken
in the Sangamo OU2 risk assessment through Monte Carlo analysis.
The advantage of this approach is that it furnishes more
information of the variability of the full range of potential
risks that may occur.
The fish ingestion pathway was chosen for Monte Carlo
analysis evaluation because this pathway is associated with the
highest potential risks. The potential cancer risk associated
Final ROD-Sangamo OU2
June 1994
with exposure to PCBs was evaluated for ingestion of bass
(largemouth and hybrids) lake-wide and for ingestion of bass
(largemouth and hybrids) caught in the area associated with the
highest PCB concentrations (i.e. SV-107). The mode of the risk
distribution is of most interest when interpreting the final
distribution of risks since it represents the most frequently
occurring risk. The most frequently occurring risk in the
distribution, or mode, was estimated to be 2 x 10-4 and 3 x 10-4
for ingestion of lake-wide bass and bass at SV-107, respectively.
The results of the Monte Carlo analysis indicated that the 1 x
10-ý risk associated with the ingestion of bass from location SV107 represented the 95th percentile of high end of the overall
risk distribution, while the 5 x 10-3 risk associated with
ingestion of lake-wide bass corresponded to the 90-95th
percentile of the overall risk distribution.
6.6
ECOLOGICAL RISK ASSESSMENT
An ecological risk assessment was conducted to evaluate the
impact PCBs may be having on aquatic receptors (plant,
invertebrates, and fish) and terrestrial receptors (birds and
mammals) of the Sangamo OU2 study area. The Biological
Investigations clearly document PCB contamination at all levels
of the aquatic food web. However, although PCBs appear to be
impacting the fish and macroinvertebrate communities in
Twelvemile Creek, habitat degradation from man's influence is
likely causing additional adverse impacts.
A 1990 investigation conducted independently of these RI
studies provided evidence that fish health and populations can be
affected as concentrations in fish increase to an average of 20
mg/kg and greater. Results from the bioindicator analyses
support the contention that individual largemouth bass may be
impacted at SV-107 and SV-106, areas closest to the Sangamo Plant
Site. However, at the present level of PCB concentrations in
fish tissue (approximately 5 mg/kg), the data from the Biological
Investigations do not support a conclusion that significant
impacts to the overall health and the population/community levels
to Lake Hartwell fish are occurring.
Ecological exposures to surface water were not directly
evaluated in the ecological assessment because PCBs were not
detected in surface water at detection limits ranging from 1.21.3 æg/L during the RI. Aquatic plants are not likely to suffer
adverse impacts from PCB concentrations just below the detection
limit. Aquatic invertebrates that are intimately associated with
sediments (primarily benthic organisms) may be adversely impacted
in the study area based on a comparison of PCB concentrations in
sediment to EPA's interim sediment quality criteria for aquatic
organisms. Reliable population estimates for avian species
(eastern phoebe, green-backed heron, belted kingfisher, osprey)
and mammals (mink, otter) that would feed in the study area were
not obtainable. Therefore, the certainty of the extent of any
population impacts caused by PCBs in the study area is unknown.
However, population effects on these terrestrial species is not
likely.
Final ROD-Sangamo OU2
June 1994
6.7
UNCERTAINTY ASSESSMENT
In any risk assessment, there is some degree of uncertainty
associated with the estimates of human and ecological risks. The
primary sources of uncertainty included environmental sampling,
exposure parameter estimation and toxicological data. Typically,
these uncertainties are compensated for by employing conservative
assumptions. Consequently, the qualitative and quantitative risk
estimates for Sangamo OU2 should not be construed as absolute
estimates of risk, but rather as conditional estimates based on a
number of assumptions regarding exposure and toxicity.
6.8
SUMMARY
The primary human health exposure pathway of concern at the
Sangamo OU2 Site is the ingestion of fish contaminated with PCBs.
Exposures associated with ingestion of fish caught from all
sampling locations resulted in unacceptable carcinogenic risks
ranging from 10-2 to 104 and HQs greater than 1. As discussed
under Section 5.4 (Contaminant Fate and Transport) of this ROD,
PCB concentrations in sediment are predicted to decrease over
time. The impact of decreasing sediment concentrations on
overall risk was evaluated for the ingestion of largemouth bass
at SV-107. The output from the food-chain bioaccumulation model
(FGETS Section 5.4.3) was utilized in this analysis. It was
found that the total modeled risk over a 30-year time frame (2 x
10-3) was not substantially different from the calculated
deterministic RME risk of 1 x 10-2. This was largely because risk
over this time period is dominated by the very high risks
calculated for the first eight years of exposure. In actuality,
a period of approximately 22 years appears to be required for
one-year risks to drop to the 10-ý risk level. It would require
more than 22 years for the entire 30-year risks to decline to <
10-6. With respect to noncancer risks, a period of approximately
20 years appears to be required for the HQ to drop below one.
After the next 20-30 years, long-term risk associated with the
consumption of fish harvested from Lake Hartwell should be
substantially lower.
Actual or threatened releases of hazardous substances for
the Sangamo OU2 Site, if not addressed by implementing the
response action in this ROD, may present an imminent and
substantial endangerment to public health, welfare, or the
environment.
Final ROD-Sangamo OU2
June 1994
TABLE 6-1
PCB Exposure Point Concentrations in Shallow Sediment
Area/
Interval
PCB Concentration (mg/kg)
Meana
95%
UCL of
Meanb
Maximum
Detected
Concentration
RME
Exposure
Point
Concentrationø
Upper 12 Mile Creek Arm
Beneath 0-2.1 m
of Lake Water
0.91
1.65
7.54
1.65
Beneath 0-3 m
of Lake Water
1.51
2.93
7.88
2.93
0.76
0.70
Upper 12 Mile Creek Watershed
Beneath 0-2.1 m
of Lake Water
0.45
0.70
Beneath 0-3 m
of Lake Water
0.45
0.72
0.91
0.72
Hagood Reservoir
Beneath 0-2.1 m
of Lake Water
0.29
0.36
0.33
0.33
Beneath 0-3 m
of Lake Water
0.28
0.33
0.33
0.33
3.52
3.52
Downgradient of Sangamo Plant
Beneath 0-2.1 m
of Creek Water
1.51
---
a)
Arithmetic mean concentration (including one-half detection
limit for non-detects).
b)
Value represents 95th percent Upper Confidence Limit (UCL)
on the arithmetic mean.
c)
RMB=Reasonable Maximum Exposure; value listed is the lower
value of the 95th percent UCL on the arithmetic mean and the
maximum detected concentration.
Final ROD-Sangamo OU2
June 1994
TABLE 6-2
Exposure Point Concentrations in Fish
Species
Mean
PCB Concentrations (mg/kg)
95%
Maximum
RME Exposure
UCL of
Detected
Point
Mean
Concentration Concentration
SV-107
Largemouth Bass
6.8
8.5
19.7
8.5
Hybrid Bass
1.4
2.0
2.3
2.0
Largemouth Bass
and Hybrid Bass
5.7
7.9
19.7
7.9
Channel Catfish
5.6
7.8
8.3
7.8
All Species
Combined
5.4
7.0
19.7
7.0
SV-106
Largemouth Bass
3.3
3.8
9.2
3.8
Hybrid Bass
4.7
8.0
9.7
8.0
Channel Catfish
2.5
3.9
4.0
3.9
All Species
3.6
Combined
SV-532
4.3
9.7
4.3
Largemouth Bass
1.7
3.8
3.5
3.5
Hybrid Bass
3.9
5.9
9.6
5.9
Channel Catfish
1.7
4.4
3.5
3.5
All Species
Combined
2.5
4.0
9.6
4.0
0.80
1.3
1.7
1.3
1.8
3.3
3.9
3.3
0.60
0.82
0.90
0.82
1.2
1.7
3.9
1.7
0.56
0.98
1.1
0.98
2.3
3.7
7.0
3.7
0.71
2.6
2.8
2.6
1.3
2.1
7.0
2.1
SV-535
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species
Combined
SV-642
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species
Combined
Final ROD-Sangamo OU2
June 1994
TABLE 6-2
Exposure Point Concentrations in Fish
Species
Mean
PCB Concentrations (mg/kg)
95%
Maximum
RME Exposure
UCL of
Mean
Detected
Point
Concentration Concentration
SV-641 (Lake Background)
Largemouth Bass 0.22
Hybrid Bass
2.0
Channel Catfish 0.41
All Species
Combined
0.74
0.3
1.2
0.3
2.8
9.3
2.8
1.4
0.8
0.8
1.1
9.3
1.1
All Areas of Lake Hartwell + 12 Mile Creek
All Species
Combined
3.0
3.9
19.7
3.9
Largemouth Bass 3.2
and Hybrid Bass
4.2
19.7
4.2
25
13.9
13.9
2.2
7.1
2.2
1.2
0.2
12 Mile Creek Watershed
Largemouth Bass 4.0
Redbreast
Sunfish
1.7
Tributaries of Watershed
Watershed
Redbreast
Sunfish
0.74
ND
Background
ND
0.2
ND
ND
Final ROD-Sangamo OU2
June 1994
TABLE 6-3
Exposure Parameters for Incidental Ingestion of and Dermal
Contact with Sediment (Current/Future Use Conditions)
Parameters
Reasonable
Maximum Exposure
Case
Age Period (years)
Exposure Frequency (days/year)a
Exposure Duration (years)
Child
4-12
105
8
Adult
>18
75
30b
Soil Ingestion Rate (mg/day)c
Skin Surface Area Available for Contact (cm)2
Sediment to Skin Adherence Factor (mg/cm2)e
Dermal Absorption Fraction (PCBs)f
Body Weight (kg)g
Averaging Time (years)
Carcinogenich
Noncarcinogenic
a)
b)
c)
d)
e)
f)
g)
h)
138
700d
1.0
0.01
27
100
1,230d
1.0
0.01
70
70
8
70
30
For children, assumes that children will swim 7 days/week
from Memorial Day to Labor Day (15 weeks) for a total of 105
exposure events/yr. For adults, assumes that adults will
swim 5 days/week for same 15 weeks for a total of 75
exposure events/yr.
Based upon national upper-bound time at one residence (USEPA
1991a, 1989a).
Value for children is a weighted-average ingestion rate,
assuming 4, 5, and 6 year olds ingest sediment at a rate of
200 mg/day and older children ingest sediment at 100 mg/day
(USEPA 1989a, 1991a). Value for adults is the standard
default value recommended by USEPA (1991a, 1989a)
Surface area based on 50th percentile values from USEPA
(1985) for feet. Values for child and adult are the timeweighted averages.
Based on USEPA Region IV guidance (USEPA 1992b).
Based on USEPA Region IV guidance (USEPA 1992b).
Value for 4-12 year old child is the time-weighted average
based on data provided by USEPA (1989b). Value for adult is
the standard default value recommended by USEPA (1991a).
Based on USEPA (1991a, 1989a) standard assumption for
lifetime.
Final ROD-Sangamo OU2
June 1994
TABLE 6-4
Exposure Parameters for Ingestion of Fish by Adult
Recreational Fisherman (Current/Future Use Conditions)
Parameters
Fish Ingestion Rate (grams/meal)a
Exposure Duration (years)b
Exposure Frequency by Sampling Location
(meals per year)c
Twelvemile Creek Watershed
SV-107
SV-106
SV-532
SV-535
SV-642
Reasonable Maximum
Exposure Value
357
30
60
30.6
27.6
20.6
22.5
37
SV-641 (Lake Background)
Lake-Wide Average
Body Weightd
Averaging Time (years)
Carcinogenice
Noncarcinogenic
a)
b)
c)
d)
e)
22.7
27.6
70
70
30
Based on the arithmetic mean of fish ingestion rates
reported for 52 anglers surveyed at Twelvemile Creek on Lake
Hartwell.
Value is based on the national upper-bound time at one
residence (USEPA 1991a, 1989a).
Values based on January to December 1992 data obtained from
Lake Hartwell Recreational Angler Survey. These values are
the arithmetic mean exposure frequency in meals/month,
multiplied by 12 months/year reported for a total of 677
anglers surveyed at Twelvemile Creek/Lake Hartwell. Final
report of survey stated that some anglers were interviewed
more than once, indicating that the survey results may
include fishing habits of subsistence fisherman as well as
recreational fisherman.
Standard default value provided by USEPA (1991a, 1989a).
Based on USEPA (1991a, 1989a) standard assumption for
lifetime.
Final ROD-Sangamo OU2
June 1994
TABLE 6-5
Potential Direct Contact Risks Associated with PCB in
Sediment
Exposure Pathway
Upper
Bound
Excess
Lifetime
Cancer
HQ for
Noncarcinogenic
Effectsa
Risk
INCIDENTAL INGESTION OF SEDIMENT
Upper Twelvemile Creek Arm
Child (4-12 years)
2 x 10-6
Adult
3 x 10-6
Upper Twelvemile Creek Watershed
Child (4-12 years)
9 x 10-7
Adult
7 x 10-7
Immediately Downgradient of Sangamo Plant Site
Child (4-12 years)
5 x 10-6
Adult
3 x 10-6
Hagood Reservoir
Child (4-12 years)
4 x 10-7
<1 (0.03)
<1 (0.01)
<1 (0.01)
<1 (0.003)
<1 (0.06)
<1 (0.02)
<1 (0.006)
Adult
3 x 10-7
<1 (0.001)
DERMAL ABSORPTION FROM SEDIMENT
Upper Twelvemile Creek Arm
Child (4-12 years)
1 x 10-7
Adult
4 x 10-7
Upper Twelvemile Creek Watershed
Child (4-12 years)
5 x 10-8
Adult
9 x 10-8
Immediately Downgradient of Sangamo Plant Site
Child (4-12 years)
2 x 10-7
Adult
5 x 10-7
Hagood Reservoir
Child (4-12 years)
2 x 10-8
Adult
4 x 10-8
<1 (0.002)
<1 (0.001)
<1 (0.0007)
<1 (0.0004)
<1 (0.004)
<1 (0.002)
<1 (0.0003)
<1 (0.0002)
Final ROD-Sangamo OU2
June 1994
TABLE 6-5
Potential Direct Contact Risks Associated with PCBs in
Sediment
Exposure Pathway
Upper
Bound
Excess
Lifetime
Cancer
HQ for
Noncarcinogenic
Effectsa
Risk
DIRECT CONTACT WITH SEDIMENT (TOTAL)
Upper Twelvemile Creek Arm
Child (4-12 years)
Adult
Upper Twelvemile Creek Watershed
Child (4-12 years)
Adult
Immediately Downgradient of Sangamo Plant Site
Child (4-12 years)
Adult
Hagood Reservoir
Child (4-12 years)
Adult
a)
2 x 10-6
3 x 10-6
<1 (0
<1 (0
1 x 10-6
8 x 10-7
<1 (0
<1 (0
5 x 10-6
4 x 10-6
<1 (0
<1 (0
4 x 10-7
3 x 10-7
<1 (0.
<1 (O.
Hazard Quotient >1 indicates exposure to PCBs may result in
adverse health effects. Actual value listed in ().
Final ROD-Sangamo OU2
June 1994
TABLE 6-6
Potential Health Risks Associated with the Ingestion of Fish
Location/Species
Upper
Bound
Excess
Lifetime
Cancer
Risk
HQ for
Noncarcinogenic
Effectsa
SV-107
Largemouth Bass
Hybrid Bass
Largemouth Bass and Hybrid Bass
Channel Catfish
All Species Combined
1
3
1
1
1
x
x
x
x
x
10-2
10-3
10-2
10-2
10-2
>1
>1
>1
>1
>1
(50)
(10)
(50)
(50)
(50)
SV-106
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species Combined
5
1
5
5
x
x
x
x
10-3
10-2
10-3
10-3
>1
>1
>1
>1
(20)
(40)
(20)
(20)
SV-532
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species Combined
3
6
3
4
x
x
x
x
10-3
10-3
10-3
10-3
>1
>1
>1
>1
(10)
(20)
(10)
(20)
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species Combined
1
3
9
2
x
x
x
x
10-3
10-3
10-4
10-3
>1
>1
>1
>1
(6)
(10)
(4)
(8)
SV-642
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species Combined
2
6
4
4
x
x
x
x
10-3
10-3
10-3
10-3
>1
>1
>1
>1
(7)
(30)
(20)
(20)
SV-535
Final ROD-Sangamo OU2
June 1994
TABLE 6-6
Potential Health Risks Associated with the Ingestion of Fish
Location/Species
Upper
Bound
Excess
Lifetime
HQ for
Noncarcinogenic
Effectsa
Cancer
Risk
SV-641 (Lake Background)
Largemouth Bass
Hybrid Bass
Channel Catfish
All Species Combined
3
3
8
1
All Areas of Lake Hartwell + 12 Mile Creek
All Species Combined
Largemouth Bass and Hybrid Bass
10-4
1O-3
10-4
10-3
>1
>1
>1
>1
(1)
(10)
(4)
(5)
5 x 10-3
5 x 10-3
>1 (20)
>1 (20)
Twelvemile Creek Watershed
Largemouth Bass
Redbreast Sunfish
4 x 10-2
6 x 10-3
>1 (200)
>1 (30)
Tributaries of Watershed
Redbreast Sunfish
6 x 10-4
>1 (20)
Watershed Background
a)
x
x
x
x
ND
ND
Hazard Quotient >1 indicates exposure to PCBs may result in
adverse health effects. Actual value listed in ().
Final ROD-Sangamo OU2
June 1994
7.0
DESCRIPTION OF ALTERNATIVES
Based upon the findings of the RI and associated Baseline
Risk Assessment (human health/ecological), EPA developed remedial
action objectives to support the identification, development and
screening of remedial alternatives. These remedial action
objectives were:
Mitigate continued migration of PCB-contaminated sediments
into Lake Hartwell by eliminating releases of PCBs into
Twelvemile Creek.
Control or eliminate the downstream migration of PCBcontaminated sediment within the Twelvemile Creek Arm of
Hartwell Lake.
Limit, to the extent feasible, the transfer of PCB
contaminants from sediment to biota.
Prevent or minimize exposure to fish with PCB contamination
above target risk (or FDA) levels.
Protection of human health is considered the primary driver
for developing and evaluating remedial action alternatives.
Thorough development and evaluation of feasible remedial
alternatives for the Sangamo OU2 Site required the derivation of
cleanup goals for the media of concern: sediment and fish.
Cleanup goals were not developed for surface water since PCBs
were not detected in any sample collected during the RI above the
detection limits of 1.2 to 1.3 æg/l. Cleanup goals for sediment
and fish were also necessary to identify areas to be addressed by
the range of remedial alternatives that were evaluated in detail.
The Final Cleanup Goals for sediment and fish, and the supporting
rationale are presented in Sections 7.1 and 7.2, respectively.
The contaminants of concern for the Sangamo OU2 Site are
total PCBs. No Aroclor- or congener-specific distinctions are
factored into the evaluation of remedial action alternatives.
Discharges from the Sangamo Weston Plant into Town Creek included
a variety of PCBs consisting predominantly of Aroclors 1242,
1254, and 1016. Analytical data for the RI included both
Aroclor-specific concentrations (from offsite CLP analyses) and
concentrations of total PCBs (from onsite field screening
analyses). However, all of the resulte, findings and conclusions
in the RI were discussed in terms of total PCBs. The reasons for
this approach are as follows:
A majority of the health-based and environmental criteria
for PCBs are stated in terms of total PCBs (i.e., FDA
tolerance level).
EPA uses a carcinogenic slope factor for PCBs that is based
on Aroclor 1260; this provides a conservative indicator of
potential health effects for all PCB mixtures.
Final ROD-Sangamo OU2
June 1994
Evaluation of contamination in terms of total PCBs was costeffective; it permitted collection of a large number of
samples and the use of field screening (Modified Spittler
Method) for sediment analyses.
7.1
FINAL CLEANUP GOAL FOR SEDIMENT
Potential cleanup goals for PCB-contaminated sediment at the
Sangamo OU2 Site were determined through an evaluation of
available criteria and accepted techniques for calculating
cleanup goals in sediment. This approach generated a range of
potentially viable cleanup concentrations for the Sangamo OU2
sediment based on the following sources:
Existing (published) criteria for PCBs in sediment,
typically derived from either geographic-based, background
PCB concentrations or biological effects observed or
predicted in aquatic organisms.
Precedents from other NPL sites where EPA has identified
protective sediment cleanup goals for PCBs that have been
finalized in RODs.
Site-specific cleanup goals calculated using EPA's
equilibrium partitioning approach based on contaminant
partitioning between sediment and sediment pore water, based
on protection of aquatic life.
From this evaluation, three representative sediment cleanup
goals (1 mg/kg, 0.4 mg/kg and 0.05 mg/kg) were selected for
further analysis. The analysis consisted of an evaluation of the
long-term impacts of potential sediment cleanup goals on PCB
concentrations in fish, and ultimately human health via ingestion
of contaminated fish, given that the ingestion of fish is the
principal exposure pathway of concern at the site. This
evaluation was conducted utilizing the FGETS bioaccumulation
model discussed in Section 5.4.3 of this ROD. The rationale for
selecting these values is presented below.
1 mg/kg - The most frequently selected sediment cleanup goal
for PCBs at NPL sites based on a review of the EPA's ROD
database. A concentration of 1 mg/kg also represents a
reasonable lower limit considering technical feasibility and
cost.
0.4 mg/kg - The mean value for the site-specific sediment
quality criteria calculated using the EPA's equilibrium
partitioning approach; also equal to the Effects RangeMedian criteria based on an evaluation of published criteria
associated with biological effects on aquatic life as
reported by the National Oceanic and Atmospheric
Administration (NOAA).
0.05 mg/kg - Equal to the Effects Range-Low from NOAA based
on an evaluation of published criteria associated with
biological effects on aquatic life; also representative of
Final ROD-Sangamo OU2
June 1994
the more commonly reported background-based sediment
criteria for PCBs.
The time required for 2-8 year old largemouth bass in the
Twelvemile Creek Arm of Lake Hartwell to achieve 2 mg/kg for the
range of selected sediment cleanup goals are compared to the
baseline condition in Figure 7-1. As shown in this figure, fish
PCB concentrations decline at about the same rate regardless of
the sediment cleanup goal. Therefore, a final sediment cleanup
goal of 1 mg/kg was selected based on technical feasibility
rather than performance or risk-based considerations. This
concentration identified the entire Twelvemile Creek Arm,
extending from the headwaters of the lake downstream to the
confluence with the Keowee Arm, as an area to be addressed. This
area covers approximately 730 acres with a total estimated volume
of 4,722,000 cubic yards (yd3) of contaminated sediment.
7.2
FINAL CLEANUP GOAL FOR FISH
Fish ingestion was identified as the primary exposure
pathway of concern at the Sangamo OU2 Site. Potential
remediation goals include the FDA tolerance level of 2 mg/kg for
PCBs in the edible portions of fish, and risk-based levels that
consider the fish ingestion exposure pathway. Both of these
options are described below.
The FDA criterion was identified as a contaminant-specific
Applicable or Relevant and Appropriate Requirement (ARAR). In
addition, the existing health advisory for Hartwell rake is based
on the continuing presence of PCBs in fish in concentrations
greater than 2 mg/kg. Selection of risk-based cleanup goals for
fish were considered by determining the concentration levels in
largemouth bass that would result in acceptable risk to anglers
(through ingestion of the fish) based on EPA's target risk range
of 1 x 10-4 to 1 x 10-6. The acceptable concentrations were
estimated using the same methodology used for the baseline human
health risk assessment and for determining risk levels for the
sediment cleanup goals. A fish tissue concentration of
0.036 mg/kg is associated with a 10-4 risk, 0.0036 mg/kg with a
10-5 risk, and so on.
Using EPA's deterministic, reasonable maximum exposure (RME)
approach and site-specific exposure parameters, the 30-year
carcinogenic risk associated with the FDA criterion of 2 mg/kg
results in an estimated risk of 6 x 10-3. This is well above the
upper end of EPA's target risk threshold of 1 x 10-4. It is
important to note that EPA considers the RME assumptions to be
conservative, since they represent upper confidence limits for a
given range of values for a particular risk input parameter or
variable. It is also important to note that consumption of fish
from Lake Hartwell (or other sources) is a strictly voluntary
activity.
Use of the risk-based concentrations for fish remediation
goals (i.e., 0.036 mg/kg) was determined to be technically
impracticable at SV-107 for several reasons. Fish bioaccumulate
PCBs from both the water column and food chain; thus, PCB
<IMG SRC 0494178T>
Final ROD-Sangamo OU2
June 1994
concentrations in sediment and surface water would likely have to
be reduced to levels in the ranges of parts per billion
(0.001 mg/kg) or parts per trillion (0.001 æg/L) to achieve riskbased levels in fish. Reducing surface water and sediment
concentrations to these levels is beyond the capability of proven
treatment technologies, particularly when the scale of the site
is taken into consideration. Moreover, as shown in the FGETS
modeling, PCB cycling among fish, plankton, benthos, sediment,
and surface water greatly complicates the removal of PCBs from a
biological system once the contaminants have been introduced.
Even if concentrations in sediment and surface water could be
reduced to levels commensurate with the risk-based fish
concentrations, it would be many years before the fish
concentrations actually declined to acceptable levels.
Given the existence of an ARAR for PCB concentrations in
fish, the technical impracticability of establishing risk-based
cleanup goals, and the classification of fish consumption as a
voluntary exposure, the FDA tolerance level of 2 mg/kg was
selected as the Final Cleanup Goal for Lake Hartwell fish.
7.3
REMEDIAL ALTERNATIVES
Response actions that were identified and passed the
screening of technologies and process options were assembled into
a range of remedial alternatives that included no action,
institutional controls, containment, collection,
removal/disposal, and removal/treatment/disposal. These eight
remedial alternatives were evaluated in detail in the Final March
1994 Feasibility Study Report. A summary description of these
alternatives follows. The reader should refer to Final FS Report
for a more detailed account of this subject matter.
All alternative cost estimates are expressed in 1993 dollars
and are based upon conceptual engineering and design. Capital
cost consists of direct (construction) and indirect (nonconstruction) costs incurred in the first year of operation.
Operation and Maintenance (O&M) cost refers to long-term
postconstruction items necessary to ensure continued
effectiveness of a remedial action. Total present worth cost
represents that sum of money, if invested in the base year and
disbursed as needed, would be sufficient to cover all costs of a
remedy over its planned life.
ALTERNATIVE 1 - NO ACTION
As required by CERCLA, a no further action alternative was
evaluated to serve as the basis for comparison with other active
cleanup alternatives. Under this no-action alternative, no
further remedial actions for the contaminated sediments or fish
at the site would be conducted. The no-action alternative would
not affect the existing health advisory issued by SCDHEC, who
would be expected to continue the advisory until PCB
concentrations in fish tissue decline to levels below 2 mg/kg
(FDA tolerance level). The advisory currently warns against the
consumption of fish from the Seneca River Arm of Hartwell Lake
above the Hwy 24 bridge and fish larger than 3 lb throughout the
Final ROD-Sangamo OU2
June 1994
entire lake. The advisory would be modified if warranted by
future trends regarding PCB levels in fish. Maintenance of the
fish advisory is assumed to entail the periodic replacement of
existing signs that advise against fish consumption.
As discussed in Section 5.4.3 of this ROD, the mean
largemouth bass PCB concentration is predicted to fall below the
FDA limit by year 10. However, a longer period of time is
required for concentrations in higher age classes to fall below
the FDA limit. PCB concentrations in 10-year-old fish,
representing the highest age class and largest fish in the model,
required 12 years, or the year 2005, to fall below the 2.0 mg/kg
FDA limit. For these reasons, it was assumed that the fish
consumption health advisory would remain in effect for 12 years.
The no-action alternative would also entail periodic reviews
of site conditions to ensure that the alternative remained
protective of human health and the environment. These reviews
would be conducted at least every 5 years as required by CERCLA.
Capital Cost = $7,000
Total O&M Cost = $123,000
Total Present Worth Cost = $130,000
ALTERNATIVE 2A - INSTITUTIONAL CONTROLS
This alternative is a limited action alternative that relies
on a series of institutional controls to prevent or minimize
ingestion of contaminated fish tissue, which was identified as
the primary exposure pathway of concern for the Site. Generally,
these institutional controls consist of the following components:
Continuance of the Existing Fish Advisory
Public Education Program - A program would be initiated to
inform the public on available methods for reducing the
intake of PCBs through fish consumption. Specific
preparation, handling, and cooking techniques can reduce the
quantity of contamination consumed. Information of this
type would be disseminated to the public through a series of
local public meetings and distribution of an informational
pamphlet.
Fish and Sediment Monitoring - In addition to maintaining
the current fish advisory, annual monitoring of PCB levels
in fish and sediment of Twelvemile Creek and Lake Hartwell
would be conducted. Results from this monitoring program
would be utilized to support modifications to the fish
advisory and to monitor concentrations of PCBs in sediment
and fish over time. Results of this program would be made
available to the public.
Regulation of Twelvemile Creek Impoundments - A routine
schedule would be developed for flushing of sediment
accumulated behind the 3 small impoundments located on
Twelvemile Creek. Periodic flushing (most recently in
September 1993) of a large load of sediment over a short
Final ROD-Sangamo OU2
June 1994
period of time has been documented to have an adverse impact
on the water quality and aquatic biota of the upper portion
of the Twelvemile Creek Arm. These adverse impacts are
attributed to elevated levels of suspended sediment and not
PCBs. A routine flushing schedule would minimize impacts to
the ecosystem while enhancing burial of more contaminated
sediments with cleaner sediments from the Twelvemile Creek
drainage.
Capital Cost = $366,000
Total O&M Cost = $2,842,000
Total Present Worth Cost = $3,208,000
ALTERNATIVE 2B - FISHERIES ISOLATION
Alternative 2B is a more aggressive approach consisting of
management of the fisheries resource within the lake to minimize
ingestion of PCB-contaminated fish. The primary control measure
includes construction of a barrier, or fish fence, to prevent the
movement of migratory fish (i.e. striped bass, hybrid bass, and
walleye) into or out of the most contaminated portions of the
reservoir. These migratory species represent approximately 50%
of the fish harvested by weight from Lake Hartwell.
Placement of the barrier in the vicinity of the Hwy 37
Bridge, just south of Clemson, would result in isolation of the
Twelvemile Creek, Keowee River, and upper Seneca River Arms,
which represent less than 10 percent of the total area of
Hartwell Lake. Isolation of these upstream areas is expected to
result in an accelerated decline in migratory fish PCB
concentrations in the downstream portions of the reservoir (i.e.,
the remaining 90+ percent of the lake). Reduction of fish PCB
levels would allow for rescinding of the existing health
advisories in these areas, returning the majority of lake areas
to normal use. This approach is consistent with the COE's Best
Management Practices for Hartwell Lake, designed to achieve the
maximum beneficial uses for the reservoir, which include fish and
wildlife management and recreational use.
The fish isolation barrier would be designed/constructed to
meet the following performance standards:
Minimize safety hazards for boaters and other users of the
lake (i.e. waterskiers);
Maximize effectiveness to prevent passage of migratory game
fish through the barrier;
Allow boats to pass unimpeded to minimize disruptions of
boating traffic on the lake (i.e. no gate);
Construct a semi-permanent structure that could be removed
once PCB levels decline to health-based levels;
Incorporate value engineering principles to minimize cost
for design and construction;
Final ROD-Sangamo OU2
June 1994
Minimize operations and maintenance requirements and costs;
Design and installation of fish fence will not impede normal
lake usage.
This alternative would require an approximate 6 month predesign (treatability type) phase to develop a detailed design in
accordance with the above performance standards. If pre-design
studies are successful, full scale construction/installation of
this remedy could be accomplished in approximately 1 year. PCBs
would continue to accumulate in the fish upstream of the fish
fence, therefore, fish are predicted to decline to protective
levels (the 2.0 mg/kg FDA tolerance level) in approximately
12 years. By isolating the impacted upstream areas, PCB
concentrations in migratory fish from the remaining 90+ percent
of the lake are predicted to decline to the 2 mg/kg level in
approximately 3-4 years.
Lake use restrictions, such as no-wake zones and warning
signs would be implemented to prevent damage to the fence and for
boating safety. Alternative 2B also includes the institutional
controls described for Alternative 2A.
Capital Cost = $1,232,000
Total O&M Cost = $3,012,000
Total Present Worth Cost = $4,244,00O
ALTERNATIVE 3A - CAPPING
Alternative 3A involves the isolation of PCB-contaminated
sediments by placing an 18 inch clean sediment cap over the areas
with the highest contamination. The cap would be constructed
using fine sand (minimum particle size 0.25 mm) to eliminate the
further downstream migration of contaminated sediment and the
transfer of PCBs from sediment to aquatic biota. The cap would
extend 7 miles from just upstream of the Maw Bridge (Rt. 337) to
the confluence with the Keowee River, just upstream of Hwy 123.
The cap would cover an area of 730 acres and would require
approximately 1,800,000 yd3 of sand to construct the cap. Figure
7-2 provides an illustration of the area to capped under this
alternative.
The cap thickness was designed to minimize the impacts
associated with bioturbation and sediment burrowing biota (i.e.
mayfly). Based upon sediment transport modeling for a cap with a
minimum particle size of 0.25 mm, no significant erosion of cap
material was observed in areas below the Madden Bridge. However
in areas above the Madden Bridge (i.e., the "goose-neck" bend
area), the model results showed erosion for all grain sizes
tested (i.e., 10, 2, and 0.25 mm). These results indicate that
maintenance of the cap would be difficult in the headwaters.
Placement of the cap would be accomplished using a hydraulic
barge unloader equipped with a sand spreader. The barge and sand
spreader would likely be supplied with sand through a slurry
pipeline between the barge and the shore or by a separate hopper
barge. A local sand source has been identified near the
community of Liberty, South Carolina. The cost estimate assumes
<IMG SRC 0494178U>
Final ROD-Sangamo OU2
June 1994
that the sand would be transported by truck to the staging area,
converted to a slurry using lake water, and pumped out to the
sand spreader barge.
Placement of the cap, including design, procurement, and
construction, would require approximately 2 years. Once the
contaminated sediments were isolated beneath the cap, further
transfer to biota would be significantly reduced, and PCB
concentrations in the fish in Twelvemile Creek Arm would decline
at an accelerated rate. A period of 3 to 4 years after cap
placement would be required for the mean concentration of PCBs in
largemouth bass filets to fall below the FDA limit of 2.0 mg/kg.
As part of cap O&M, detailed hydrographic surveys would need to
be conducted periodically to assess the integrity and overall
performance of the clean sediment cap. These surveys would focus
on the upstream segment of the cap in the area where sediment
deposition and scour processes are most active.
Alternative 3A also consists of lake usage restrictions to
minimize erosion of the cap once it is placed and other
institutional controls described under Alternative 2A.
Capital Cost = $48,296,000
Total O&M Cost = $2,843,000
Total Present Worth Cost = $51,139,000
ALTERNATIVE 3B - SEDIMENT CONTROL STRUCTURE
Alternative 3B involves the construction of a 1,600 ft.
fixed-crest weir near the mouth of the Twelvemile Creek Arm. The
weir would maintain a constant pool elevation of 660 ft MSL in
the Twelvemile Creek Arm, minimizing the scour/erosion and
resuspension of contaminated sediment in the headwaters and
thereby reducing the downstream migration of PCB-contaminated
sediment into Hartwell Lake. The constant pool elevation may
also enhance the burial of these contaminated sediments in the
upstream reaches. In addition, the weir would greatly reduce the
migration of fish into and out of Twelvemile Creek Arm. The
location of the sediment control structure is shown on Figure 73.
The weir, or sediment control structure, would be an
effective barrier to the downstream movement of suspended bedload sediments, which are transported just above the sedimentwater interface. The weir would allow water to flow from the
Twelvemile Creek Arm to Hartwell Lake but would otherwise be an
effective physical barrier between the two water bodies. The
sediment control structure would not allow the passage of boats
or other watercraft, and lakeshore property owners in the
Twelvemile Creek Arm would not have direct boating access to or
from Hartwell Lake. Monthly pool elevation data and the
reservoir operating rule curve were used to select the crest
elevation for the weir. Based on the pool elevation data, it is
estimated that the pool elevation for Lake Hartwell is above
660 ft MSL approximately 23 percent of the time. The sediment
control structure would be constructed of concrete by utilizing
proven cofferdam techniques.
<IMG SRC 0494178V>
Final ROD-Sangamo OU2
June 1994
Implementation of Alternative 3B, including design and
construction of the weir and establishment of institutional
controls, would require approximately 2 years. Within the newly
impounded Twelvemile Creek Lake, contaminated sediments would not
be isolated from the biota and future contaminant trends in the
fish would be as described under the Alternatives 1 and 2A. The
time to achieve protectiveness in the main body of Lake Hartwell
(i.e., the approximate 90+ percent of the total lake area
downstream of the sediment control structure) was assumed to be
comparable to that predicted for Alternative 2B (fish fence),
given that both the weir and fish fence would greatly limit the
movement of fish into and out of the area with the most highly
contaminated sediment. Using this approach, the FDA Tolerance
Level in migratory fish downstream of the sediment control
structure would be attained in an estimated 3 to 4 years after
construction of the weir was completed.
To ensure public safety, watercraft would be restricted from
the immediate vicinity of the sediment control structure.
Fishing restrictions in the isolated area, as well as
institutional controls under Alternative 2A, would be implemented
to limit consumption of contaminated fish until protective levels
were achieved.
Capital Cost = $51,226,000
Total O&M Cost = $2,365,000
Total Present-Worth Cost = $53,591,000
ALTERNATIVE 3C - OPTIMAL CAPPING/SEDIMENT CONTROL STRUCTURE
Value engineering techniques were used to combine elements
of Alternatives 3A and 3B to achieve similar results with
significantly lower costs and reduced impact to lakeshore
residents and property owners. Figure 7-4 provides a conceptual
approach to this alternative.
The sediment control structure for Alternative 3C consists
of a fixed-crest weir similar in design to the structure proposed
in Alternative 3B. The proposed location for the weir under
Alternative 3C is approximately 1,000 ft upstream of the Hwy 133
bridge. Placement of the structure at this location would
isolate the areas having the highest levels of PCB contamination
in the sediment while at the same time effectively isolating a
smaller portion of the Twelvemile Creek Arm from the main lake.
Moving the weir upstream also allows for its placement at a
relatively narrow constriction of the channel, resulting in a
much smaller weir (length-wise) and construction cost. The weir
would also maintain an upper pool elevation of 660 ft, minimizing
scour and resuspension of contaminated sediment in the headwaters
of the Twelvemile Creek Arm. This action would minimize the
migration of contaminated sediment into the lower portion of the
Twelvemile Creek Arm and Hartwell Lake. The weir is also
expected to reduce the movement of fish into and out of the areas
of highest sediment PCB contamination.
The area downstream of the sediment control structure to the
mouth of the Twelvemile Creek Arm would be capped under this
Final ROD-Sangamo OU2
June 1994
<IMG SRC 0494178W>
Final ROD-Sangamo OU2
June 1994
alternative using the same performance criteria (e.g., prevent
burrowing into underlying sediment), conceptual design parameters
(e.g., 18-in. thick, sand-silt mixture), and construction methods
(i.e., hydraulic sand spreader barge) as described for the
Alternative 3A. The area for capping consists of approximately
285 acres and would require approximately 700,000 yd3 of material
to construct. Cap integrity below the weir would be maintained
using riprap and other reinforcing materials to prevent scour
from flow over the top of the weir.
Construction of the sediment control structure and placement
of the cap would require a period of 2 to 3 years. Upstream of
the weir, contaminated sediments are not isolated from the biota
and thus PCB concentration in fish would continue to exceed the
FDA limit of 2.0 mg/kg for the an estimated 12 years. Downstream
of the weir in the Twelvemile Creek Arm, cap placement would
accelerate the reduction of PCB levels in fish to protective
levels because contaminated sediments have been isolated,
limiting further transfer of PCBs to biota. An estimated period
of 3 to 4 years (after cap placement) is required for PCB
concentrations to fall below the FDA limit of 2.0 mg/kg in the
capped area as well as in the main body of Hartwell Lake.
Institutional controls under Alternative 2A and fishing
restrictions upstream of the sediment control structure would be
implemented until protective levels in the fish were achieved.
Capital Cost = $31,684,000
Total O&M Cost = $2,365,000
Total Present Worth Cost = $34,049,000
ALTERNATIVE 4 - CONFINED DISPOSAL FACILITY
Alternative 4 involves a much more rigorous remediation
approach than any of the alternatives discussed above. This
alternative involves removal by hydraulic dredging of
contaminated sediment from the Twelvemile Creek Arm with PCB
concentrations greater than 1 mg/kg followed by disposal of the
dredged material in a Confined Disposal Facility (CDF). The
conceptual approach to this alternative is shown in Figure 7-5.
Implementation of Alternative 4 would be a complex undertaking
controlled through scheduling and rigid conformance to procedural
requirements needed to minimize environmental impacts. The
following discussion provides an overview of the remedial
construction activities associated with Alternative 4:
Excavate channel - Rerouting the Twelvemile Creek Arm would
begin immediately south of the high-tension powerline
crossing and would proceed due south for a distance of
approximately 1,600 ft. where it would reconnect with the
original lake channel. The rerouted channel would be
approximately 50 ft. wide at the base with a maximum
excavation depth for the channel at approximately 55 ft.
Material excavated during the channeling operation would be
used for construction associated with the CDF. Rerouting
the channel in this area would only isolate one shoreline
residence on the goose-neck bend.
<IMG SRC 0494178X>
Final ROD-Sangamo OU2
June 1994
Construct Confined Disposal Facility - The COE commonly uses
CDFs for disposal of dredged sediments. The goose-neck bend
area between Maw and Madden Bridges was selected as the
optimum location for the following reasons: 1) this area has
most highly contaminated sediments avoiding the need to
dredge approximately 1.3 million yd3 of material; 2)
approximately 113 acres is available providing sufficient
capacity for disposal of 5 million yd3 of material; and 3)
minimal impacts on existing residents would occur.
Dredge and pump dredged sediment into CDF - Sediments from
entire Twelvemile Creek Arm with PCB concentrations >1 mg/kg
would be removed via hydraulic dredging and transported to
CDF via pipeline. Sediment would settle out in CDF, while
water was returned to the lake.
Compact/grade pediment to promote runoff followed by
placement of soil cap over CDF.
Additional detailed information regarding dredging
techniques, dredged material characteristics, and design of the
CDF would be required prior to implementation of Alternative 4.
Implementation of the dredging alternative is expected to require
a period of 3 to 4 years (including treatability testing, design,
procurement and construction). Once sediments with greater than
1 mg/kg of PCBs have been removed from the lake, the FGETS model
predicts that the mean PCB concentration in largemouth bass
fillets would fall below the FDA limit of 2.0 mg/kg in 5 to
6 years. Institutional controls would be used to limit
consumption of contaminated fish until protective levels were
achieved.
Capital Cost = $43,422,000
Total O&M Cost = $3,487,000
Total Present Worth Cost = $46,9O9,000
ALTERNATIVE 5 - STABILIZATION
Alternative 5 is a very complex and costly alternative that
involves removal of contaminated sediments with PCB
concentrations greater than 1 ppm via a combination of shallow
water excavation and hydraulic dredging. Contaminated sediments
in the middle and lower portions of Twelvemile Creek Arm would be
dredged while the upper portion is dewatered and excavated. The
dredged/excavated sediments would be treated by stabilization
with cement and placed in a CDF as described under Alternative 4.
Fish and other biota in the upstream segment would be collected
and destroyed as part of the dewatering operations. This
alternative was evaluated in an attempt to satisfy the preference
for treatment as a principal element for selected remedial
alternatives at NPL sites.
Implementation of Alternative 5 would likely trigger a
substantial number of ARARs, the most significant being the Clean
Water Act and South Carolina Water Classification Standards.
Based on a volume estimate of 4,722,000 yd3 for excavation and
dredging, expected stabilization production rates, and the rate
Final ROD-Sangamo OU2
June 1994
at which the confined disposal facility can be filled,
implementation of Alternative 5 would entail a duration of 4 to 5
years. Once the contaminated sediment has been removed, fish PCB
concentrations downstream of the Madden Bridge would decline at
an accelerated rate, achieving the FDA tolerance level in
approximately 5 to 6 years. The time to achieve protectiveness
for this alternative therefore is 9 to 11 years.
Capital Cost = $581,957,000
Total O&M Cost = $3,486,000
Total Present Worth Cost = $585,443,000
8.0
SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
This section documents the comparative analysis conducted to
evaluate the relative performance of each alternative in relation
to each of the evaluation criteria. The purpose is to identify
and clearly understand the advantages and disadvantages of each
remedial alternative described in Section 7.0 of this ROD. As
stated in NCP [40 CFR 300.430 (f)], the evaluation criterion are
arranged in a hierarchial manner that is then used to select a
remedy for the site based on the following categories:
Threshold Criteria:
Overall Protection of Human
Health and the Environment
Compliance with ARARs
Primary Balancing Criteria:
Long-term Effectiveness and
Reduction of Toxicity,
Mobility, or Volume
Short-term Effectiveness
Implementability
Cost
Modifying Criteria:
State Acceptance
Community Acceptance
The Threshold criteria must be met before an alternative is
eligible for selection as a preferred alternative in the Proposed
Plan and ultimate selection in the ROD. The five Primary
Balancing Criteria provide the basis for determining which
alternative provides the best balance of trade-offs among all
others considered. The State of South Carolina has reviewed this
ROD and concurs with EPA's selected remedy described in Section
9.0. The State of South Carolina concurrence letter is attached
as Appendix A to this ROD. Community Acceptance is addressed in
the Responsiveness Summary attached as Appendix B to this ROD.
The following discussion addresses the Threshold and Primary
Balancing Criteria.
8.1
OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
Overall protection of human health and the environment
addresses whether each alternative provides adequate protection
of human health and the environment and describes how risks posed
Final ROD-Sangamo OU2
June 1994
through each exposure pathway are eliminated, reduced, or
controlled, through treatment, engineering controls, and/or
institutional controls.
Complexities related to the cycling of PCBs in the biota of
Lake Hartwell cause residual risk levels to remain above 1 x 10-4
regardless of which remedial action alternative is implemented.
A reduction in sediment PCB concentrations does not result in an
immediate reduction in PCB concentrations in fish. High PCB
concentrations in fish during the initial years of the 30-year
exposure duration result in average risk estimates exceeding
acceptable levels. Therefore, all of the alternatives rely on
institutional controls to minimize exposures to PCB-contaminated
fish tissue (limiting these exposures was identified as one of
the primary remedial action objectives). These controls include
public education and continuation of the current fishing
advisory.
The most protective alternatives are those that rely
principally on engineering rather than institutional controls to
reduce or eliminate exposures, given the uncertainty regarding
the performance/reliability of the institutional controls. The
removal/disposal and removal/treatment/disposal actions under
Alternatives 4 and 5, respectively, provide the highest level of
protectiveness, as the contaminated material is removed from the
lake and isolated in an engineered disposal facility.
Alternative 2B entails construction of a fish fence to be
designed and constructed so as to maximize effectiveness while
minimizing operations and maintenance; however, additional, predesign studies would be needed to develop the actual design for
the structure. Alternatives 3A and 3C involve capping actions
that should permanently isolate the contaminated sediment in all
or a major portion of the Twelvemile Creek Arm. The capping
would be highly protective of human health and the environment;
its reliance on long-term monitoring and maintenance to assure
cap integrity is a disadvantage but does not compromise the
overall protectiveness or long-term effectiveness of the action.
8.2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs)
Section 121 (d) of CERCLA requires that remedial actions at
NPL sites at least attain legally applicable or relevant and
appropriate federal and state requirements, standards, criteria
and limitations which are collectively referred to as "ARARs",
unless such ARARs are waived under CERCLA section 121 (d) (4).
Applicable requirements are those substantive environmental
protection reguirements, criteria, or limitations promulgated
under federal or state law that specifically address hazardous
substances found at the site ("contaminant-specific ARARs), the
remedial action to be implemented at the site ("action-specific
ARARs"), the location of the site ("location-specific ARARs"), or
other circumstances at the site. Relevant and appropriate
requirements are those substantive environmental protection
requirements, criteria, or limitations promulgated under federal
or state law which, while not applicable to the hazardous
substances found at the site, the remedial action itself, the
Final ROD-Sangamo OU2
June 1994
site location or other circumstances at the site, nevertheless
address problems or situations sufficiently similar to those
encountered at the site that their use is well-suited to the
site.
All of the alternatives rely on natural fate and transport
processes to reduce PCB concentrations in Lake Hartwell fish to
the FDA tolerance level of 2 mg/kg. Several alternatives include
actions designed to speed up the rate at which these natural
processes act (i.e. by capping or removing contaminated
sediment). No contaminant-specific ARARs for PCBs in sediment
were identified, which led to the identification of To-BeConsidered (TBC) criteria and the selection of a sediment cleanup
goal of 1 mg/kg based on an evaluation of these criteria.
Alternatives 3A (Capping), 4 (Confined Disposal Facility) and
5 (Stabilization) would best achieve the TBC criteria for
sediment. The sediment control structures (Alternatives 3B and
3C) are expected to impact PCB concentrations in the sediment,
but not to the same extent as capping or removal.
Alternatives 4 and 5 would trigger the largest number of and
most complex action- and location-specific ARARs, including the
Clean Water Act dredge-and-fill requirements, South Carolina
requirements for surface water discharges, and, if PCB
concentrations in dredged/excavated sediments exceed 50 ppm TSCA
requirements for handling/storage/treatment/disposal. The
alternatives could be designed and implemented to attain
compliance with these requirements. Capping activities under
alternatives 3A and 3C would also trigger Clean Water Act and
South Carolina requirements related to surface water discharges;
compliance with these requirements would be factored into the
design and implementation. Action-specific ARARs were not
identified for the institutional controls under any alternative
or for construction of the fish fence under Alternative 2B.
8.3
LONG-TERM EFFECTIVENESS AND PERMANENCE
Long-term effectiveness and permanence refers to the
expected residual risk and the ability of a remedy to maintain
reliable protection of human health and the environment over
time. The criterion includes the consideration of residual risk
and the adequacy and reliability of controls.
Contaminant transport and bioaccumulation modeling conducted
during the RI showed that Lake Hartwell is a dynamic system in
which PCB concentrations in sediment and biota are gradually
declining in response to natural fate and transport processes
such as burial by clean sediment, resuspension and desorption
followed by flushing out of the reservoir, and other processes.
The modeling results indicate that PCB levels in the sediment
will decline below the 1 mg/kg cleanup goal in 5 to 10 years
(depending on location within Twelvemile Creek Arm) and that PCB
concentrations in fish will decline to the FDA tolerance level in
12 years. If the modeling predictions are accurate, even
Alternative 1 (No Action) would eventually result in a permanent
solution for the site in approximately 12 years, given that
consumption of contaminated fish was the primary exposure pathway
of concern.
Final ROD-Sangamo OU2
June 1994
Alternatives 2 to 5 rely on institutional controls to
prevent exposure to contaminated fish; the performance and
reliability of these controls is dependent on site-specific
factors and therefore difficult to predict. In the context of
technology performance and reliability, the fish fence
(Alternative 2B) has not been proven for the same scale of
application proposed for Sangamo OU2. Capping (Alternatives 3A
and 3C) is a proven technology but is dependent on an extensive
program of monitoring and maintenance to ensure cap integrity and
long-term effectiveness. Capping of only the downstream portion
of the Twelvemile Creek Arm under Alternative 3C would result in
a cap that was easier to maintain, and therefore, it should have
a higher degree of long-term effectiveness. Sediment control
structures (Alternatives 3B/3C) are also widely used and are less
dependent on maintenance.
Although dredging and confined disposal facilities are
widely recognized as reliable technologies, further technology
evaluation, in the form of pilot-scale treatability studies,
would be needed to obtain design and operating data essential to
minimize environmental impacts. Similarly, stabilization
treatability studies under Alternative 5 would require further
technology evaluation to determine material handling and process
requirements (e.g., optimum stabilization mixture). Treatability
studies are also needed to determine effluent treatment
requirements for the dewatering fluids from the confined disposal
facility or material handling/stockpiling areas.
8.4
REDUCTION OF TOXICITY, MOBILITY, OR VOLUME
Reduction of toxicity, mobility, or volume through treatment
refers to the anticipated performance of the treatment
technologies for the remedy. None of the alternatives has an
effect on the toxicity of the contaminants, expect Alternative 5
which involves treatment by stabilization. Alternative 5 would
accomplish the most significant reduction in the mobility of PCBs
through a stabilization treatment process, followed by disposal
in a confined disposal facility. Contaminant mobility would also
be reduced through disposal in a CDF, with no treatment, in
Alternative 4.
The capping alternatives (Alternatives 3A and 3C) also
accomplish a reduction in contaminant mobility, but the effect is
contingent upon proper maintenance of the cap. Reductions in
contaminant mobility are expected with the sediment control
structures (Alternatives 3B and 3C), primarily through
maintaining pool elevation, thereby decreasing scour/erosion in
the headwaters. The capping, sediment control structures and
fish fence alternatives also reduce PCB transfer to migratory
fish by isolating the contaminated sediment (through capping) or
restricting the migration of fish into and out of the areas with
the highest sediment contamination (through the fence or weirs).
The net result is a reduction in the level of PCB contamination
in lake-wide migratory fish.
Final ROD-Sangamo OU2
June 1994
8.5
SHORT-TERM EFFECTIVENESS
Short-term effectiveness refers to the period of time needed
to complete the remedy and any adverse impacts on human health
and the environment that may be posed during the construction and
implementation of the remedy.
Implementation of Alternatives 1 (No-Action) and 2A
(Institutional Controls) would have the least impact on the
community, workers, and the environment; Alternative 2B has only
a slightly greater impact. Alternatives 3A/3B/3C have greater
impacts on the local community due to construction of sediment
control structures and excessive truck traffic associated with
the transportation of capping material. The greatest impacts
(and least short-term effectiveness) are associated with the more
aggressive alternatives that entail dredging, re-channeling, and
construction of the CDF (Alternatives 4/5).
Table 8-1 summarizes the estimated schedule for each
alternative, presenting the time required to implement, time
required for fish PCB concentrations to decline to protective
levels (FDA tolerance level), and total time for alternative to
achieve protectiveness. Because the most highly contaminated
sediment is concentrated in a relatively small, upstream portion
of the lake that represents less than 10 percent of the reservoir
area, separate estimates are shown for the time to attain FDA
levels and time to achieve protectiveness in both this upstream
portion (i.e., the Twelvemile Creek/Seneca River Arm) and in the
main body of Hartwell Lake. The impact on a given alternative
with regard to protective levels throughout the lake is an
important consideration given the significant resource potential
of the reservoir. It is important to note that the time required
for implementation includes design, procurement, and construction
but does not consider the time between issuance of the Proposed
Plan/signing of the ROD and initiation of the Remedial Design.
The table shows that isolation or removal of the most highly
contaminated sediment, through fisheries isolation, capping,
sediment control structures, or dredging often has a much greater
effect on PCB levels in downstream areas than within the
Twelvemile Creek Arm. This response is mostly due to the impact
of limiting or preventing the movement of migratory fish into and
out of the areas with the more highly contaminated sediment
(lake-wide, non-migratory fish have exceeded the FDA levels on an
infrequent and isolated basis while migratory fish have typically
had PCB levels higher than 2 mg/kg). Accelerated declines in PCB
levels would be expected for alternatives involving capping or
removal; otherwise, PCB reductions would be accomplished only
through natural fate and transport processes conditions.
The most favorable alternatives with regard to the estimated
time to achieve protectiveness would be Alternatives 2B and 3A;
fisheries isolation (Alternative 2B) is more quickly implemented
and therefore leads to a slightly faster reduction in PCB levels
in the main body of Hartwell Lake but the capping alternative
would have a much greater effect in the Twelvemile Creek/Seneca
River Arm. If more than 1 to 2 years elapse between the signing
Final ROD-Sangamo OU2
June 1994
Table 8-1
Estimated Time to Achieve Protectiveness
TIME FOR FISH TO ATTAIN FDA LEVEL
TIME TO A
PROTECTIVENESS(4)
(yrs)
ALT.
BODY OF
NO.
DESCRIPTION
HARTWELL LAKE
2
No action
2A Institutional
TIME TO
IMPLEMENT(1)
(yrs)
TWELEMILE
CREEK/SENECA
RIVER(2) ARM
0
0.5
12
12
MAIN BODY OF
HARTWELL LAKE(3)
12
12
R
2B
3A
3B
3C
4
5
Fisher Isolation
Capping
Sediment Control Structure
Optimal Capping/Sediment
Control Structure
Confined Disposal Facility
Stabilization
1
2
2
2-3
3-4
4-5
12
3-4
12
3-4 (downstream)
12 (upstream
5-6
5-6
3-4
3-4
12
3-4
5-6
5-6
NOTE: (1) Includes time needed for pre-design studies, procurement, and constr
between Proposed Plan/Record of Decision and initiation of
Remedial Design.
(2) Twelvemile Creek Arm only; FGETS modeling results indicate that fish
mg/kg) in approximately 12 years under baseline conditions;
none of the alternatives will extend the period required for this to
period to achieve protectiveness of greater than 12 yrs).
(3) Downgradient of the Twelvemile Creek Arm (i.e., main body of Hartwel
decline more rapidly for actions involving isolating, capping or removal
of contaminated sediment (Alternatives 2B, 3A-C, 4 and 5). It was a
comparable to that observed in the Twelvemile Creek Arm for
Alternatives involving capping (3-4 yrs) or removal of the sediment
verify this estimated.
(4) Duration only; based on estimated time to implement remedy and durat
to decline to FDA level, based on the FGETS modeling
results presented in Section 3.3 and assumptions regarding migratory
Final ROD-Sangamo OU2
June 1994
of the ROD and the initiation of the Remedial Design, the
dredging alternatives (Alternatives 4/5) will not achieve
protectiveness appreciably faster than that obtained under
baseline (no-action) conditions.
8.6
IMPLEMENTABILITY
Alternatives 1 and 2A would be the most readily
implementable; the main activity associated with the
institutional controls under Alternative 2A (and other
alternatives) involves planning and coordination with COE,
SCDHEC, and other agencies. Alternative 2B (Fish Fence) would be
somewhat more complex to implement, primarily due to the
predesign testing to assess the suitability of various designs.
Alternatives 3A, 3B, and 3C represent an intermediate range
of implementability. Capping and weirs have been successfully
constructed at a wide variety of sites and conditions at Hartwell
Lake and should not present any unusual difficulties. The
reduced scale of the area to be capped and size of weir for
Alternative 3C would simplify both design and construction
activities associated with these individual components. A
limitation to Alternative 3A and, to a lesser extent, 3C,
concerns the availability and transportation logistics of as much
as 1.8 million yd3 of capping material. From a technical and
engineering perspective, construction of the fixed crest weirs
for Alternatives 3B and 3C should be much more implementable than
capping due to the likelihood of encountering problems with the
capping materials.
The most difficult alternatives to implement, in terms of
both technical and administrative feasibility, would be
Alternatives 4 and 5; both involve dredging, which is a widely
used technology, but they would still require considerable
predesign testing and evaluation to optimize operations and
minimize environmental impacts. Construction of the confined
disposal facility in what is currently a large body of open water
and rechanneling the Twelvemile Creek Arm through a forested
ridge would also present a number of technical challenges, while
not insurmountable, the challenges do make implementation of
Alternatives 4 and 5 considerably more complex than the other
remedial alternatives. These alternatives would also have the
greatest administrative requirements due to the need to fulfill
permit-related requirements related to Clean Water Act dredgeand-fill permits, South Carolina NPDES permits, and possibly
other permitted activities.
8.7
COST
Costs for each alternative were provided under Section 7.3
of this ROD. Alternative 5 is the most expensive alternative to
implement, and is considered cost prohibitive. The more
aggressive alternatives (Alternatives 3A/3B/3C/4) that involve
engineering controls to satisfy the remedial action objectives
have total present worth costs that generally range from $30-50
million. Alternative 2B achieves protectiveness in the main body
of Lake Hartwell in a shorter amount of time than the other more
Final ROD-Sangamo OU2
June 1994
aggressive and passive (Alternatives 1/2A) alternatives for only
an additional $1 million over the cost of Alternative 2A
(estimated present worth cost of $3,208,000). The No-Action
alternative is the least expensive.
9.0
THE SELECTED REMEDY
This section of the ROD discusses EPA's selected remedy in
detail for the Sangamo OU2 Site. EPA has selected Alternative 2A
- Institutional Controls to address the contaminated sediments
and fish at the Site. The selected remedial alternative for the
Sangamo OU2 Site consists of the following components: 1)
continuation of existing fish advisory; 2) public education
program; 3) future sediment and aquatic biota monitoring; and 4)
regulation of the Twelvemile Creek Impoundments. These primary
components are discussed below.
9.1
CONTINUATION OF EXISTING FISH ADVISORY
The existing fish advisory on Lake Hartwell shall remain in
effect. Signs warning against consuming fish have been posted at
the majority of the public boat launch and recreation areas since
1987. Figure 9-1 provides an illustration of the posted
advisory. The advisory is currently maintained by SCDHEC, and
SCDHEC will remain responsible for management, supervision, and
administration of the fish consumption advisory in the future.
The advisory will be modified if warranted by future trends
regarding PCB concentrations in fish. Modifications shall be
fully supported and justified by the annual monitoring program
discussed in Section 9.3 of this ROD.
Maintaining the fish advisory will likely entail the posting
and replacement of signs describing the advisory at access points
along the shoreline. For purposes of enhancing the effectiveness
of the advisory, additional signs may be posted. Additional
activities designed to increase public awareness of the existing
fish consumption advisory are discussed in Section 9.2 of this
ROD.
As discussed in the Section 5.4.3, FGETS bioaccumulation
food-chain modeling, the mean PCB concentration in 2-8 year old
largemouth bass is predicted to fall below the FDA limit by year
10. However, a longer period of time is required for
concentrations in higher age classes to fall below the FDA limit.
PCB concentrations in 10-year-old fish, representing the highest
age class and largest fish in the model, required 12 years to
fall below the 2.0 mg/kg FDA limit. For these reasons, it was
assumed that the fish consumption health advisory would remain in
effect for a minimum of 12 years, or the year 2005.
9.2
PUBLIC EDUCATION PROGRAM
Proper preparation of contaminated fish can reduce the
quantity of contamination consumed. Contaminants (PCBs) are
generally stored in fatty tissue (i.e., belly flap, strip along
the backbone and lateral line, and skin). By removing these
Final ROD-Sangamo OU2
June 1994
ATTENTION
FISH CONSUMPTION ADVISORY-LAKE HARTWELL
S.C. DEPARTMENT OF HEALTH AND
ENVIRONMENTAL CONTROL (SCDHEC)
ALL FISH TAKEN FROM THE SENECA RIVER ARM
OF LAKE HARTWELL NORTH OF SC HIGHWAY 24
AND 12 MILE CREEK SHOULD BE RELEASED AND
NOT EATEN.
ALL FISH LARGER THAN THREE (3) POUNDS
TAKEN FROM THE REMAINDER OF LAKE HARTWELL SHOULD BE RELEASED AND NOT EATEN.
FISHING IS NOT PROHIBITED BUT SCDHEC
ADVISES THAT THESE FISH NOT BE EATEN DUE
TO THE PRESENCE OF ELEVATED LEVELS OF
POLYCHLORINATED BIPHENYLS (PCBs). SWIMMING, BOATING, AND OTHER WATER RELATED
ACTIVITIES ARE NOT RESTRICTED BY THIS
ADVISORY.
FOR ADDITIONAL INFORMATION,
CONTACT SCDHEC AT:
COLUMBIA
734-5300
GREENVILLE
242-9850
ANDERSON
225-3731
Figure 9-1
Current Lake Hartwell Fsh Advisory
Final ROD-Sangamo OU2
June 1994
areas when cleaning the fish, individuals can substantially
reduce their intake of PCBs. Broiling, baking, and grilling fish
also provides additional risk reduction. Many states, including
Georgia, provide fish preparation suggestions to the public in
pamphlets and other publications on state fishing regulations;
South Carolina currently does not.
EPA shall develop a pamphlet that outlines methods,
including those described above, for reducing the intake of
contaminants through fish consumption. This pamphlet will be
distributed to the general public and to frequent Lake Hartwell
resource users. The most effective method of distribution to the
general public is to provide the pamphlet to everyone who
purchases a fishing license. Thus, all establishments that sell
fishing licenses in the Hartwell Lake area will be supplied with
the pamphlets, as will marinas and selected retail establishments
(i.e., convenience stores) in the area. In addition to the
pamphlets, advertisements will be placed periodically in
newspapers from all of the counties surrounding the lake. The
advertisements will reiterate the potential risks associated with
consumption of PCB-contaminated fish from Lake Hartwell.
Printed information regarding the fish advisory will also be
supplemented with periodic public meetings hosted by EPA, SCDHEC,
and the COE. Public meetings will begin the first year following
signing of the ROD and will be held at a minimum of 5-year
intervals. The public meetings will serve to update the general
population on PCB concentration trends in sediment and fish as
well as the latest estimates of PCB-related risks resulting from
consumption of contaminated fish. Analytical results from the
annual monitoring program described in Section 9.3 and the fiveyear reviews, as required by CERCLA, will be disseminated to
those attending these meetings, local citizens, and frequent lake
users. The meetings would also provide a forum for public input
into the decision-making process regarding continued
institutional controls for the lake. The proposed locations for
these meetings include:
Anderson, S.C.
Cateechee/Norris S.C.
Clemson, S.C.
Hartwell, Ga.
Seneca, S.C.
The above public education program represents a baseline
approach. EPA, COE, and SCDHEC will periodically evaluate the
overall approach and effectiveness of this program by soliciting
public comment and input from Lake Hartwell resource users.
Creel surveys, similar to those conducted as part of the
Biological Investigation, may also be utilized as a mechanism to
obtain information from anglers on Lake Hartwell. The public
education program is expected to evolve while attempting to
identify the most productive method(s) for reaching the targeted
audience. EPA, in close consultation with SCDHEC and the COE
shall modify the public education program as required.
Final ROD-Sangamo OU2
June 1994
9.3
AQUATIC BIOTA AND SEDIMENT MONITORING
This section describes the program of annual monitoring of
PCB levels in the fish, corbicula, and sediment of Lake Hartwell
and the Twelvemile Creek watershed.
9.3.1
AGUATIC BIOTA MONITORING
In the interest of consistency and to support trend
analysis, fish samples will be collected from the same 6 Lake
Hartwell stations that have been utilized historically by SCDHEC
and also during the Biological Investigation. These stations are
shown on Figure 9-2 and are generally described as follows:
SV-107
Twelvemile Creek Arm of Lake Hartwell in the vicinity
of County Road 37; Pickens County, SC.
SV-106
Seneca River Arm of Lake Hartwell in the vicinity of
Martin Creek; Anderson County, SC.
SV-532
Seneca River Arm of Lake Hartwell in the vicinity of
Eighteen Mile Creek; Anderson County, SC.
SV-535
Andersonville Island area of Lake Hartwell near the
confluence of the Tugaloo and Seneca Rivers; Anderson
County, SC.
SV-641
Tugaloo River Arm of Lake Hartwell in the vicinity of
Interstate I-85; Oconee County, SC.
SV-642
Open water area of Lake Hartwell in the vicinity of
Hartwell Dam; Anderson County, SC.
Fish samples shall be collected annually in the spring using
gill nets and/or electrofishing techniques. Hybrid bass (weight
class 3.0-5.0 lbs.), largemouth bass (weight class 1.5-3.0 lbs.)
and channel catfish (weight class 2.0-4.0 lbs.) will be collected
from the above 6 stations in Lake Hartwell. In past sampling
events, 10 hybrid bass, 10 largemouth bass, and 4 catfish were
collected at each station to calculate a representative mean.
The adequacy of these respective numbers in determining a
representative mean concentration in fish tissue is currently
under review by SCDHEC. In any event, sampling conducted
pursuant to this ROD will at a minimum include 10 hybrid bass, 10
largemouth bass, and 4 catfish. Game fish shall be prepared in
accordance with the standard US FDA fillet method ti.e., fillet
including rib cage and belly flap with skin on and scales off except for catfish where skin is removed.). All fish shall be
analyzed for the PCB component of EPA,s Target Compound List
(TCL).
Forage fish, consisting of gizzard shad/blueback herring,
threadfin shad and bluegill, shall be collected at stations SV107, SV-532, and SV-641. Forage fish will be collected
concurrently with game fish sampling discussed above using
electrofishing techniques. Samples will consist of whole body
composite samples for each species. All forage fish samples
<IMG SRC 0494178Y>
Final ROD-Sangamo OU2
June 1994
shall be analyzed for PCBs. Data generated from the forage fish
collection and analyses shall be utilized to support future foodchain modeling activities.
In addition to fish sampling in Lake Hartwell, corbicula
(fresh water clams) baskets will be placed at 6 locations in
Twelvemile Creek for 28 days each in the spring of each year to
determine current PCB loading into the Twelvemile Creek system.
The sampling locations for corbicula baskets are shown on Figure
9-3. Corbicula baskets will be deployed concurrent with the fish
sampling activities described above. After 28 days, baskets
shall be recovered and analyzed for PCBs.
9.3.2
SEDIMENT MONITORING
Sediment monitoring locations are shown in Figures 9-4 and
9-5. Sediment samples shall be collected annually from 15
locations in Hartwell Lake and 5 locations in the watershed.
Sediments will be collected using a ponar dredge. Stations SD001 through SD-005 in the Twelvemile Creek watershed will be
discrete samples. For the remaining 15 locations in Lake
Hartwell, a transect shall be established at each station and 5
grab samples will be collected along the transect. These 5
samples shall be composited to provide a mean concentration of
PCBs in surface sediments from a given transect. Sample and
transect locations shall be established with sufficient accuracy
to enable collection of future samples from same locations.
Details of the sediment sample locations in Twelvemile Creek and
Lake Hartwell are presented in Table 9-1.
All sediment and aquatic biota monitoring shall continue
under the direction of EPA. Data from the annual monitoring will
allow EPA, SCDHEC and COE to continue ongoing efforts to evaluate
contamination trends in the sediment and biota. These trends
will be used to support decisions to modify the advisory, in
response to PCB concentration trends in the fish. Annual
monitoring results shall be summarized and disseminated to the
public in support of the public education program described under
Section 9.2. For purposes of the cost estimate described in
Section 9.6, it was assumed that this annual monitoring program
will continue for a minimum of 15 years from signature of the
ROD.
9.4
REGULATION OF TWELVEMILE CREEK IMPOUNDMENTS
The Federal Energy Regulatory Commission (FERC) regulates
hydroelectric facilities in the U.S. Currently, the middle and
lower impoundments on Twelvemile Creek, Woodside I and II,
respectively, are non-licensed hydroelectric impoundments based
on the date of construction and navigability of Twelvemile Creek.
These impoundments effectively trap a large portion of the
sediment load from Twelvemile Creek, and as a result, are flushed
periodically to remove sediment and to restore storage capacity
within the impoundments. Historically, these trapped sediments
have contained high levels of PCBs. However, the RI and
subsequent sampling in response to a recent flushing event
(September 1993) have shown that more recent sediment
<IMG SRC 0494178Z>
<IMG SRC 04941781>
<IMG SRC 04941782>
Final ROD-Sangamo OU2
June 1994
TABLE 9-1
Sediment Sample Locations in Twelvemile Creek Watershed and
Arm of Lake Hartwell
Station ID
Location
SD-001
Town Creek downstream of Sangamo Weston
outfall - same location as corbicula basket 2
SD-002
Twelvemile Creek upstream of Wolf Creek
confluence - same location as corbicula basket 3
SD-003
Wolf Creek downstream of Breazeale site - same
location as corbicula basket 4
SD-004
Twelvemile Creek at Easley-Central impoundment same location as corbicula basket 5
SD-005
Twelvemile Creek at Lay Bridge
SD 006
Maw Bridge
SD-007 - 009
Between Maw and Madden Bridges
SD 010
Madden Bridge
SD-011
Between Madden and Hwy 133 Bridges
SD-012
Hwy 133 Bridge
SD-013
Mouth of Twelvemile Creek Arm
SD-014
Between US 123 and Hwy 93 Bridges
SD-015
Hwy 37 Bridge
SD-106
SV-106 fish sampling station
SD-532
SV-532 fish sampling station
SD-535
SV-535 fish sampling station
SD-641
SV-641 fish sampling station
SD-642
SV-642 fish sampling station
accumulating behind the small dams has relatively low levels of
PCB contamination (1 to 3 mg/kg). These low concentrations
confirm that PCB-contaminated sediments continue to flow down
Twelvemile Creek into Hartwell Lake, but the magnitude of this
contaminant flux is small.
Although flushing of these impoundments is not currently
contributing appreciable quantities of PCB contamination to the
Twelvemile Creek Arm of the lake, the release of the equivalent
of a half-year's sediment load (or more) during a short time
period (typically less than 1 week) has been documented to have
potentially significant adverse effects on water quality in the
upper portion of the Twelvemile Creek Arm. The influx of
sediment in the most recent flushing event (September 1993) was
observed to result in a notable fish kill in Twelvemile Creek
below the impoundments and in the upper portion of the Twelvemile
Final ROD-Sangamo OU2
June 1994
Creek Arm. This was attributed to elevated levels of suspended
sediments and not PCBs. Similar and possibly more damaging
effects to benthic organisms within the upper portion of the
reservoir are also likely to occur.
The frequency at which these impoundments are flushed is
based primarily on an operations schedule established by the
owner/operator rather than hydraulic or other technical
constraints. To minimize the negative impacts on water quality,
and to facilitate burial of relatively more contaminated
sediments downstream, EPA's selected remedy shall include the
development of a routine schedule for sluicing of all three
impoundments (i.e., Woodside I and II, and Easley-Central Water
District). Quarterly flushing of these impoundments is thought
to be adequate to minimize the negative impacts.
Preliminary discussions with Consolidated Hydro, Inc.,
owners/operators of Woodside I and II, have indicated a
willingness to comply with this requirement. It is estimated
that approximately $200,000 in capital improvements to the gating
mechanisms are necessary to fulfill the objectives of this
component of EPA's selected remedy. Compliance with the routine
schedule shall be monitored by SCDHEC. In addition, water
quality and sediment monitoring will be conducted on downstream
areas during the sluicing events to facilitate modification of
the schedule as needed.
9.5
FIVE YEAR REVIEWS
As required by CERCLA, 5-year reviews will be conducted to
ensure that the alternative remains protective of human health
and the environment. The results of the annual monitoring
studies shall be incorporated into the 5-year reviews. The 5year reviews shall continue at intervals no less often than 5
years following signature of this ROD until protectiveness has
been achieved.
9.6
COST ESTIMATE
Table 9-2 provides a cost breakdown, by component, of Alternative
2A - Institutional Controls. The estimated total present worth
cost for EPA's selected remedy is $3,208,000, which includes
$366,000 of capital costs.
Final ROD-Sangamo OU2
June 1994
TABLE 9-2
Cost Estimate for EPA's Selected Remedy, Alternative 2AInstitutional Controls
Remedy Component/
Cost Item
Fish Advisory
Public Education
Capital
Cost ($)
$4,000
O&M Cost
($/yr.)
$1,000
$33,000
O&M Cost
($5/yrs.)
$25,000
Present
Worth
Cost ($)
$12,000
$314,000
Biota & Sediment
Monitoring
Twelvemile Creek
Impoundments
5-Year Reviews
Subtotal
$132,000
$1,202,000
$200, 000
$200,000
$204,000
$166,000
$28,000
$53,000
$60,000
$1,788,000
10%
5%
$20,000
$10,000
$17,000
$8,000
$5,000
$3,000
$179,000
$89,000
15%
$31,000
$265,000
$25,000
$216,000
$8,000
$69,000
$268,000
$2,324,000
Indirects/Profit
Subtotal
Contingency
20%
TOTAL
$40,000
$305,000
$61,000
$366,000
$32,000
$248,000
$50,000
$298,000
$10,000
$79,000
$16,000
$95,000
$349, 000
$2,673,000
$535,000
$3,208,000
Engineering
Procurement
Construction
Management
Subtotal
10.0 STATUTORY DETERMINATIONS
This section of the ROD describes how EPA's selected remedy,
Alternative 2A - Institutional Controls, meets the statutory
requirements as delineated in Section 121 of CERCLA.
10.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The extent to which EPA' selected remedy is protective of
human health and the environment is directly dependent upon the
effectiveness of the institutional controls that are the
principal components of this response action. The reliability of
the institutional controls in limiting exposure is difficult to
predict due to the significance of site-specific demographic
factors governing the likely response of the public to the
advisory and other component of this remedy that are designed to
limit exposures. Risks posed by the primary exposure pathway,
ingestion of PCB contaminated fish, are declining due to natural
fate and transport processes, primarily the burial of
contaminated sediment. Baseline modeling activities predict that
PCB concentrations in largemouth bass fillets would decline to
the FDA tolerance limit in approximately 12 years (year 2005).
Final ROD-Sangamo OU2
June 1994
Effective implementation of the institutional controls described
in Section 9.0 of this ROD would limit exposures until PCB
contamination dropped to these protective levels. Therefore,
this alternative is considered to be adequately protective of
human health and the environment.
10.2 COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS
The only applicable requirement identified for the selected
remedy is the contaminant-specific ARAR governing PCB
concentrations is fish. Continuation of the existing fish
advisory in conjunction with the aggressive public education
program addresses the FDA requirement governing consumption of
PCB contaminated fish.
No sediment-related, contaminant-specific ARARs were
identified. TBC and health-based criteria for sediment were
identified in the discussions of ARARs and sediment cleanup
goals. Alternative 2A does not attain the TBC or health-based
levels directly, but these levels would be attained through
natural sedimentation processes in the reservoir. Depending on
the area of the Twelvemile Creek Arm, the selected TBC sediment
cleanup goal of 1 mg/kg will be attained in a period of 5-10
years.
10.3 COST EFFECTIVENSS
EPA believes this remedy will minimize risks posed to human
health and the environment at an estimated cost of $3,208,000.
Complexities related to the cycling of PCBs in the aquatic biota
of Lake Hartwell cause residual risk levels to remain above
acceptable levels regardless of which remedial alternative is
implemented. The most effective means to limit exposure to PCBcontaminated fish is by the effective implementation of the
primary components of EPA's selected remedy, Alternative 2A Institutional Controls. Therefore, in terms of risk-reduction
for money spent, Alternative 2A is the most cost-effective
remedial alternative that was evaluated in detail by EPA.
10.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PARTICABLE
EPA has determined and the State of South Carolina has
concurred with EPA's determination that the selected remedy
represents the maximum extent to which permanent solutions can be
utilized in a practicable manner for Operable Unit Two of the
Sangamo Site. Engineering controls and treatment technologies
did not offer a significant advantage in terms of overall risk
reduction for the cost. EPA and the State have determined that
the selection of Alternative 2A - Institutional Controls,
provides the best balance of trade-offs in terms of the five
balancing criteria, while also considering the statutory
preference for treatment as a principal element and community
acceptance. The selected remedy addresses the primary risk
associated with Sangamo OU2, the ingestion of PCB contaminated
fish, by the most effective means practicable.
Final ROD-Sangamo OU2
June 1994
10.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
EPA's selected remedy does not satisfy the preference for
treatment as a principal element due to the excessive costs (>
$500 million) associated with removal, treatment and disposal of
approximately 4.7 million cubic yards of PCB contaminated
sediment spread out over approximately 730 acres. Moreover,
alternatives that involved aggressive engineering controls to
contain, remove, and dispose of PCB contaminated sediment ranged
from $30-$50 million without offering a significant advantage in
terms of overall risk reduction.
11.0 DOCMENTATION OF SIGNIFICANT CHANGES
Pursuant to the requirements of Section 117(b) of CERCLA,
this section of the ROD documents and discusses the reasons for
significant changes made to the selected remedy from the time the
Proposed Plan was released to the public to the final selection
of the remedy in this ROD. For reference, the Proposed Plan is
attached to this ROD as Appendix C. Specific written and/or oral
comments received during the formal 60-day public comment period
held from April 11 through June 10, 1994 are discussed in the
Responsiveness Summary (Appendix B).
EPA's preferred alternative, as delineated in the Proposed
Plan, was Alternative 2B - Fisheries Isolation. In addition to
the Institutional Controls under Alternative 2A, Alternative 2B
also involved the construction of a fishery isolation barrier
("fish fencer") to prohibit the movement of migratory fish into or
out of the area of Lake Hartwell with the highest PCB
concentrations in sediment. Placement of the fish fence near the
Hwy 37 Bridge, just south of Clemson on the Seneca River Arm,
would result in isolation of less than 10 percent of the total
area of Lake Hartwell. Isolation of these upstream areas was
expected to result in accelerated declines in PCB concentrations
in migratory fish in the downstream portions of Lake Hartwell
(i.e. the remaining 90+ percent of the lake).
The reasons supporting EPA's preference for Alternative 2B
were simply: 1) Migratory species represent approximately 50% of
the fish harvested by weight from Lake Hartwell. Accelerated
reductions of PCB concentrations in these fish, for the majority
of Lake Hartwell, would achieve a higher degree of protection by
eliminating, or at the very least, minimizing exposures to this
group of migratory fish; 2) Reduction in fish PCB levels would
allow for rescinding of the existing fish advisories in the areas
downstream of the fish fence, in an accelerated time frame, thus
returning the majority of Lake Hartwell to its highest beneficial
use; 3) The incremental cost to implement Alternative 2B was
only approximately $1 million over that of Alternative 2A.
Moderate, yet unwavering public opposition was expressed to
EPA's preferred alternative at the Proposed Plan public meeting
held in Clemson, SC on April 19, 1994. This and subsequent
comments received during the public comment period suggest that
the general consensus supports Alternative 2A and/or no-further
Final ROD-Sangamo OU2
June 1994
action. In summary, the reasons supporting public opposition to
Alternative 2B were essentially two-fold. First, the public does
not believe EPA is capable of designing, constructing and
installing a safe fishery isolation barrier that would meet the
specified performance standards (See Section 7.3) at the
estimated cost. Secondly, given the fact that Institutional
Controls provide the most reliable mechanism for reducing
exposures to PCB contaminated fish, the incremental cost for
constructing a fish fence is not justified.
EPA has given serious consideration to the concerns that
were voiced by the public. In response to these concerns, EPA,
in close consultation with SCDHEC and the Savannah District Corps
of Engineers, has selected Alternative 2A - Institutional
Controls as the Final remedial alternative for the Sangamo OU2
Site.
Appendix
Proposed Plan Fact Sheet
UNITED STATES ENVIROMENTAL PROTECTION AGENCY
SUPERFUND PROPOSED PLAN FACT SHEET
SANGAMO WESTON/TWELVE MILE CREEK/LAKE
HARTWELL PCB CONTAMINATION SUPERFUND SITEOPERABLE UNIT TWO
Pickens County, South Carolina
A number of terms specific to the Superfund process (printed in bold print
end
of this publication.
INTRODUCTION
The Region IV office of the United States
Environmental Protection Agency has
developed this Proposed Plan Fact Sheet for
the Sangamo Weston/Twelvemile
Creek/Lake Hartwell Polychlorinated
Biphenyl (PCB) Contamination Superfund
Site - Operable Unit Two ("Sangamo OU2
Site") in Pickens County, South Carolina.
This Proposed Plan is issued to present the
altenatives that EPA has considered to
address PCB contamination in the sedinment
and aquatic biota of the Sangamo OU2 Site.
More specifically, the purpose of this
Proposed Plan is to:
Identify the preferred alternative for
remedial action at the Site and explain the
rationale for that preference;
Describe the other remedial options
considered in detail in the Final Feasibility
Study Report;
Solicit public review of and comment on
all of the alternatives described; and
Provide information on how the public
can be involved in the remedy selection
process at the Sangamo OU2 Site.
PROPOSED P
MEE
for
SANGAMOSUPERFUND
Tuesday,
7:
RAMAD
U.S. 76
Clemson,
EPA, in consulta
Distact of the U
Engineers (COE)
Department of He
Control (SCDHEC)
ramedy for the S
public comment p
information subm
been reviewed an
encouraged to su
alternatives, an
supports these a
Remedial Project
of this publicat
presented in a R
could differ fro
depending upon n
EPA receives dur
comment period.
EPA is issuing this Proposed Plan as part of
its public participation responsibilities under
Section 117(a) of the Comprehensive
Environmental Response, Compensation
and Liability Act (CERCLA, more
commonly known as Superfund). This fact
sheet summrizes information that can be
found in greater detail in the Remedial
Investigation/Feasibility Study (RI/FS)
Reports and other site-related documents
contained in the Administrative Record,
located at the established information
repositories. The reader is referred to the
information repositories listed at the end of
this publication for a more detailed account
of this subject matter.
SITE BACKGROUND
From l955 to 1987, Sangamo Weston, Inc.
owned and operated a capacitor eaten.
manufacturing plant in Pickens, South
Carolina, near the headwaters of Lake
Hartwell. In its manufacturing processes,
Sangamo used several varieties of dielectric
fluids which contained PCBs. Waste
disposal practices from the Sangamo Plant
included land burial of off-specification
capacitors and wastewater treatment sludges
on the plant site and at six satellite disposal
areas. PCBs were discharged with untreated
effluent directly into Town Creek, which is
a tributary of Twelvemile Creek.
Twelvemile Creek is a major tributary of
Lake Hartwell. It is estimated that over
400,000 lbs. of PCBs were released into the
Twelvemile Creek system until the use of
PCBs were discontinued prior to an EPA ban
in January 1978. Schlumberger Industries,
Inc. (SII) is the current owner of the plant
site, as a result of a merger with Sangamo
Weston in December 1989.
Historical sampling events conducted by
SCDHEC, COE, and EPA documented the
presence of widespread PCB contamnation
Field sampling and analysis for the sediment
of the sediments,
biota from the San
Town Creek through
well into the Twel
Hartwell. During
was discovered tha
of Late Hartwell c
exceeded the recom
by the U.S. Food a
(U.S. FDA). Subse
a fish consumption
issued in 1976 and
SCDHEC in 1985 as
to reduce human ex
states: 1) All fi
River Arm of Lake
Highway 24 and Twe
be released and no
larger than 3 lbs.
Lake Hartwell shou
eaten. This advis
warning signs agai
posted at the majo
launch and recreat
In 1987, based upo
Ranking System, SC
programs and accom
citizens in the ar
proposed for inclu
Priorities List (N
was finalized on t
A Remedial Investi
separate sediment
components, was th
nature and extent
the Sangamo OU2 st
study area extends
Weston Plant's dis
Creek, through the
watershed, and fin
of Lake Hartwell.
this publication p
illustration of La
surrounding area.
focused descriptio
Arm and decrea
component of the OU2 RI was performed in
July and August 1991 (Phase I) and April
and May 1992 (Phase II). The sediment
investigation included the collection and
analysis of over 1,100 sediment cores and
grab samples to adequately characterize the
horizontal and vertical distribution of PCB
contamination in the sediments of the study
area. The sediment investigation determined
that most of the PCB-contaminated sediment
lies within the upper portion of Lake
Hartwell, specifically the Twelvemile Creek
Arm. PCB concentrations of surficial
sediments (i.e. grab samples) were typically
less than 5 parts per million (ppm), but
higher concentrations up to 61 ppm were
detected in the deeper sediments (i.e. core
samples). Figure 3 illustrates average
sediment PCB concentrations for an
approximate 10 mile reach extending from
Maw Bridge(Rt. 337)to the Rt 37 Bridge at
the southernmost boundary of the focused
OU2 study area.
Field sampling and analysis for the
biological component of the OU2 RI was
conducted in the Spring of 1991 and 1992.
Largemouth bass, catfish, and hybrid bass
were collected and analyzed from 6 stations
in Lake Hartwell. These stations are
illustrated on Figure 4. The biological
investigation determined that fish in the
Twelvemile Creek drainage and Lake
Hartwell are contaminated with PCBs, often
at levels that exceed FDA's safe tolerance
level of 2 ppm. Furthermore, caged fresh
water clams and forage fish (small, young
fish) accmulated PCBs over a relatively
short period of time which confirmed the
presence of food chain and respiratory
transport mechanisms. PCB concentrations
in sedentary fish (i.e. largemouth bass,
catfish) are highest in the Twelvemile Creek
downstream, si
sediment conta
species (i.e.
concentrations
entire reservo
frequently exc
level. PCB co
bass and hybri
stations, year
Figures 5 and
SCOPE OF THE P
The Sangamo Si
Units. Operab
the land-based
the Sangamo We
satellite disp
mile radius of
Industries, un
initiated clea
November 1993.
consist of exc
contannnated s
disposal areas
excavated mate
facilities at
The excavated
storage facili
treatment syst
site, at which
materials will
temperature th
This publicati
to present the
for Operable U
addresses the
migration rout
land-based sou
final response
implement as p
remediating th
SUMMARY OF SITE RISKS
Human Risk
CERCLA directs EPA to protect human
health and the environment from current and
potential exposure to hazardous substances at
the Site. A Baseline Risk Assessment was
The risks associated
fish were calculated
stations in Twelvemil
Hartwell (Figure 4).
conducted to evaluate the potential current
and future human health and ecological
impacts associated with exposure to PCBs in
sediment and fish. The human exposure
pathways which were quantitatively
evaluated under current and future land-use
conditions included: 1) Ingestion and dermal
absorption of PCBs in the shallow sediment
by a child and an adult; and 2) Ingestion of
PCB-contaminated fish by a recreational
fisherman. PCBs were not detected in the
surface water during the RI and therefore
this medium was not evaluated in the risk
assessment.
EPA evaluated PCBs according to their
potential to produce either cancer and/or
noncancer health effects. The carcinogenic
risk range EPA has set for Superfund
cleanups to be protective of human health is
1 X 10-4 to 1 X 10-6. For example, a cancer
risk of 1 X 10-6 indicates that an individual
has a 1 in 1,000,000 (or 1 in 10,000 for 1 X
10-4) incremental chance of developing
cancer as a result of site-related exposure to
a carcinogen over a 70 year lifetime under
the specific exposure conditions at the Site.
EPA generally uses the cumulative
benchmark risk level of 1 X 10-4 for all
exposures relating to a particular medium to
trigger action for that medium. Noncancer
exposure estimates were developed using
EPA reference doses to calculate a Hazard
Quotient (HQ). A HQ greater than 1
indicates that PCBs are present at
concentrations that could produce harmful
effects.
at the population level for fish that have
PCB concentrations around 5 ppm.
However, there is evidence that as
concentrations increase to greater than 20
ppm, fish health can be effected.
Based upon the results of the Baseline Risk
Assessment, it was concluded that actual or
threatened releases of hazardous substances
from this Site, if not addressed by the
preferred alternative or one of the other
separately by fish sp
species combined to a
individuals who may e
exclusively and indiv
types of fish. Expos
ingestion of fish cau
stations resulted in
ranging from 10-2 to
than 1. The highest
was calculated for an
consuming largemouth
Twelvemile Creek wate
cancer risk for inges
combined, 1 X 10-2, w
Twelvemile Creek Arm.
associated with inges
combined was 5 X 10-3
health risks resultin
incidental ingestion
unlikely to occur, ho
continuing source of
aquatic biota of the
Ecological Risk
An ecological risk as
to evaluate the impac
on the aquatic recept
The biological invest
document PCB contamin
the aquatic food web.
PCBs appear to be imp
macroinvertebrate com
Twelvemile Creek, hab
man's influence is li
adverse impacts at th
community levels. Th
Lake Hartwell does no
Final Fish Cleanup Go
safe tolerance level
based upon technical
carcinogenic risk-bas
evaluated by determin
levels in largemouth
in acceptable risk to
ingestion of fish. U
assessment methods, a
concentration of 0.03
with a 10-4 risk. Th
active measures considered, may present a
current or potential imminent and/or
substantial endangerment to public health,
welfare, or the environment.
SUMMARY OF ALTERNATIVES
Thorough development and evaluation of
feasible remedial alternatives for the
Sangamo OU2 Site required the derivation of
cleanup goals for the media of concern:
sediment and fish. Cleanup goals were not
developed for surface water since PCBs were
not detected in any sample collected during
the RI above the detection limits of 1.2 to
1.3 ppb. Cleanup goals were also necessary
to identify areas to be addressed by EPA's
preferred alternative. The final cleanup
goals are discussed below.
Final Sediment Cleanup Goal Concentration of 1 ppm was selected based
upon technical feasibility. Remediation goal
of 1 ppm identified the entire Twelvemile
Creek Arm, extending from the headwaters
of the lake downstream to the confluence
with the Keowee Arm, as an area to be
remediated. This area covers approximately
730 acres with a total estimated volume of
4,722,000 cubic yards of contaminated
sediment.
would be conducted. The existing fishing
advisory would continue and 5-year reviews
would be conducted to assess sediment/fish
PCB concentrations and associated risks to
human health and the environment.
goal of 0.036 ppm was
technically impractab
In a similar fact she
and in the Final FS R
the range of remedial
under consideration f
alternatives are brie
All alternative cost
in 1993 dollars and a
conceptual engineerin
cost consists of dire
indirect (non-constru
the first year of ope
maintenance (O&M) cos
postconstruction item
continued effectivene
Total present worth c
of money, if invested
disbursed as needed,
cover all costs of a
life.
Alternative 1:
No Ac
As required by CERCLA
alternative was evalu
basis for comparison
cleanup alternatives.
no further remedial a
contaminated sediment
Sediment Quality Tre
The objective of sed
was to predict the f
in the surface and b
Twelvemile Creek/Lake Ha
Due to the complex, dynamic nature of the
over the next 30 yea
Lake Hartwell system, significant changes in
sediments upstream o
the nature and extent of contamination are
are predicted to dec
expected over time even under the no-action
within 5 years. Sed
scenario. A comprehensive modeling effort
133 Bridge and the H
consisting of sediment transport, water
predicted to fall be
quality and contaminant transport, and foodgoal in approximatel
chain bioaccumulation was conducted during
bottom sediments lyi
the RI to predict the future fate and transport
Bridge and the Hwy 3
of PCBs in sediments and aquatic biota of
to increase and rema
the study area. The predicted results of this
cleanup goal after 3
modeling exercise are important
increase is attribut
considerations when evaluating the no-action
alternative. For this reason, the predicted
results of the baseline modeling activities are
summarized below.
finer, clay sized pa
constriction of the
embankment.
Future Sedimentation
Bioaccumulation and
Fish Concentrations
The objective of sediment modeling was to
determine the rates at which presently
contaminated sediments would be buried by
relatively clean sodiments from tributary
drainages over the next 30 years. Average
sediment burial rates for the 30 year
simulation are presented in Figure 7.
Substantial rates of sediment deposition are
predicted from Maw Bridge (Rt. 337) to just
above the Hwy 133 Bridge. All of the sand
and most of the silt coming into the
reservoir from the Twelvanile Creek
drainage are deposited in this reach with a
predicted 30-year accumulation of nearly 10
feet of sedimet in some areas. This
deposition pattern is favorable since PCB
concentrations have historically been higher
in sediments from this portion of the study
area.
Aquatic bioaccumulat
conducted to assess
fish would change over t
the contaminated sedimen
unmanaged, and 2) H
for levels to drop be
goal. A representa
developed to evalua
into fish via respi
contaminated food. Larg
selected as the top p
shad/bluegill sunfish
plankton and bentho
levels of the food
PCB concentrations for t
web are presented in
bioaccumulation mod
concentrations to d
food web during thc 30-y
PCB concentrations in older largemouth bass
are predicted to fall below the 2 ppm
cleanup goal by 2005.
Capital Cost = $7,000
Total O&M Cost = $123,000
Total Present Worth Cost = $130.000
Alternative 2A:
Institutional Controls
This alternative is a limited action alternative
that relies on a series of institutional controls
to prevent or minimize ingestion of
contaminated fish tissue, which was
identified as the primary exposure pathway
of concern for the Site. GeneraUy, these
institutional controls consist of the
following:
Public Education Program - A program
would be initiated to inform thc public on
available methods for reducing the intake
of PCBs through fish consumption.
Regulation of
Impoundments be developed f
accumlated beh
impoundments l
Creek. Period
September 1993
sediment over
been documente
impact on the
biota of thc u
Twelvemile Cre
impacts are at
suspended sedi
routine flushi
impacts to the
burial of more
with cleaner s
Twelvemile Cre
Capital Cost = $
Total O&M Cost =
Total Present Wo
Specific preparation, handling, and
cooking techniques can reduce the
quantity of contamination consumed.
Information of this type would be
disseminated to the public through a series
of local public meetings and distribution
of an informational pamphlet.
Fish and Sediment Monitoring - In
addition to maintaining the current fish
advisory, annual monitoring of PCB levels
in fish and sediment of Twelvemile Creek
and Lake Hartwell would be conducted.
Results from this monitoring program
would be utilized to support modifications
to the fish advisary and to monitor
concentrations of PCBs in sediment and
fish over time. Results of this program
would be made available to the public.
Minimize safety hazards for boaters and
other users of the lake (ie. waterskiers);
Maximize effectiveness to prevent passage
of migratory game fish through the
barrier;
Allow boats to pass unimpeded to
minimize disruptions of boating traffic on
the lake (i.e. no gate);
Construct a semi-permanent structure that
could be removed once PCB levels
decline to health-based levels;
Incorporate value engineering principles to
minimize cost for design and construction;
and
Minimize operations and maintenance
requirements and costs.
Lake use restrictions, such as no-wake zones
and warning signs would be implemented to
prevent damage to the fence and for boating
safety. Alternative 2B also includes the
institutional controls described for
Alternative 2A.
Capital Cost = $1,232,000
Alternative 2B:
Alternative 2B i
approach consist
fisheries resour
minimize ingesti
fish. The prima
construction of
prevent the move
striped bass, hy
or out of the m
the reservoir.
represent approx
harvested by wei
The fish isolati
the vicinity of
designed/constru
perfonrmance sta
123. The cap would
acres and would req
1,800,000 yd3 of sa
Alternative 3A also
restrictions to min
once it is placed a
controls described
Capital Cost = $48,
Total O&M Cost = $2
Total Present Worth
Alternative 3B:
Structure
Se
Alternative 3B woul
a 1,600 ft. long fi
of the Twelvemile C
the confluence with
Construction of the
structure would phy
Twelvemile Creek Ar
of Lake Hartwell re
downstream migratio
sediment and moveme
areas with highest
Fishing restriction
well as institution
Altarnative 2A, wou
limit consumption o
Total O&M Cost = $3,012,000
Total Present Worth Cost = $4,244,000
Altenative 3A:
Capping
Under this alternative, an 18 inch clean
sediment cap would be placed over the
entire Twelvemile Creek Arm to eliminate
thc further downstream migration of
contaminated sediment and the transfer of
PCBs from sediment to aquatic biota. The
cap would extend from just upstream of the
Maw Bridge (Rt. 337) to the confluence with
the Keowee River, just upstream of Hwy
resulting in the physical isolation of a much
smaller area than Alternative 3B. A similar
clean sediment cap as described under
Alternative 3A would be placed below the
weir and extend downstream to the mouth of
the Twelvemile Creek Arm. The area to be
capped under this alternative is
approximately 285 acres. Institutional
controls under Alternative 2A and fishing
restrictions for the isolated area would be
implemented until protective levels in the
fish were achieved.
Capital Cost = $31,684,000
Total O&M Cost = $2,365,000
Total Present Worth Cost = $34,049,000
Alternative 4:
Confined Disposal Facility
Alternative 4 involves a much more rigorous
remediation approach than any of the
alternatives discussed above. Under this
alternative, contaminated sediments from the
Twelvemile Creek Arm with PCB
concentrations greater than 1 ppm would be
removed by hydraulic dredging. All dredged
sediments would be placed in a near-shore
confined disposal facility (CDF) located in
the "goose neck" bend area between the
Maw (Rt. 337) and Madden (Rt. 15)
Bridges. Twelvemile Creek would then be
diverted around the CDF via a physically
rerouted channel. lnstitutional contro
would be used to limit comumption of
contaminated fish until protective levels
protective levels w
Capital Cost = $51,
Total O&M Cost = $2
Total Prment Worth
Alternative 3C: Op
Sediment Control St
Alternative 3C util
techniques to optim
capped and location
The weir would be c
upstream location n
concentrations gr
combination of sh
hydraulic dredgin
in the middle and
Twelvemile Creek
while the upper p
excavated. The d
would be treated
cement and placed
under Alternative
the upstream segm
and destroyed as
operations. Inst
used to limit con
fish until protec
Capital Cost = $5
Total O&M Cost =
Total Present Wor
EVALUATION OF ALT
EPA has estlished
comparing the adv
eath alternative
alternatives disc
against one anoth
specified in the
40 CFR 300.430(e)
evaluation criter
1)
2)
Overall Prote
and the Envir
Compliance wi
Relevant and
were achieved.
3)
Capital Cost = $43,422,000
Total O&M Cost = $3,487,000
Total Present Worth Cost = $46,909,000
Alternative 5:
Stabilization
Altarnative 5 is a very complex and costly
alternative that involves removal of
contaminated sediments with PCB
The first two criteria are referred to as
threshold criteria and must be met for an
alternative to be eligible for selection. The
next five criteria are referred to as balancing
criteria and are used to weigh major tradeoffs among alternatives. The final two
criteria, state and community acceptance, are
referred to as modifying criteria and are
addressed during the proposed Plan comment
period. The following discussion briefly
evaluates the relative performance of each
alternative to the evaluation criteria.
Overall Protection of Human Health and the
Environment - It is important to note that
complexities related to cycling of PCBs in
the biota of Lake Hartwell cause the residual
risk levels to remain above EPA's threshold
of 1 X 10-4 regardless of which remedial
alternative is implemented. A reduction in
sediment PCB concentrations does not result
in an immediate reduction in PCB
concentrations in fish. High PCB
concentrations in fish during the initial years
of the 30-year exposure duration result in
average risk estimates exceeding acceptable
levels. Therefore, the most effective
measures to minimize exposures to PCBcontaminated fish tissue are institutional
controls (i.e. public education, continuation
of fish advisory).
However, the most protective alternatives
rely principally on engineering rather than
institutional controls to reduce or eliminate
exposures, gives the uncertainty regarding
the performance/reliability of institutional
controls. Alternatives 3A and 3C involve
capping actions that would permanently
4)
5)
6)
7)
8)
9)
(ARARs)
Long-term Eff
Premanence
Reduction of
Volume
Short-term Ef
Implementabil
Cost
State Accepta
Community Acc
protectiveness, a
is removed from t
engineered dispos
Compliance with A
assesses the over
Federal/State req
alternatives rely
processes to redu
Lake Hartwell fis
level of 2 ppm.
capping and isola
2B/3A/3B/3C) achi
quicker in the ma
Alternatives 3A,
the cleanup goal
However, Alternat
trigger a large n
requirements asso
dredging, and dis
Long-term Effecti
With the exceptio
Alternative, all
institutional con
contaminated fish
reliability of th
site-specific fac
predict. The fis
would require pre
to demonstrate ef
application at Sa
(Alternatives 3A/
but is dependent
monitoring and ma
integrity and lon
Sediment control
widely used and a
maintenance. Fur
isolate the contaminated sediment in all or a
major portion of the Twelvemile Creek Arm.
The more aggressive alternatives 4 and 5
provide an even higher level of
Reduction of Toxciity. Mobility, or Volume
- Alternative 5 would accomplish the most
significant reduction in the mobility of PCBs
through a stabilization treatment process
followed by disposal in CDF. The capping
alternatives (Alternatives 3A/3C) also
accomplish a reduction in contaminant
mobility, but the effect is contingent upon
proper maintenance of the cap. The
sediment control structures (Alternatives
3B/3C) and fish fence (Alternative 2B)
would be the most effective in limiting
contaminant mobility related to the migration
of fish into and out of the areas with the
highest sediment contamination.
Short-term Effectiveness - Implementation of
Alternatives 1 (No-Action) and 2A
(Institutiona1 Controls) would have the least
impact on the community, workers, and the
enironment; Alternative 2B has only a
slighly greater impact. Alternatives
3A/3B/3C have greater impacts on the local
community due to construction of sediment
control structures and excessive truck traffic
associated with transportation of capping
material. The greatest impacts (and least
short-term effectiveness) are the more
aggressive alternatives that entail dredging,
re-channeling and construction of the CDF
(Alternatives 4/5).
Table 1 at the end of this publication
summarizes the estimated schedule for each
alternative, presenting the time required to
implement, time required for fish PCB
concentrations to decline to the FDA safe
tolerance level, and total time to achieve
protectiveness. This information is presented
for the focused Sangamo OU2 study area
(Twelvemile Creek/Seneca River Arm) as
well as the main portion of Lake Hartwell
The table shows that most of the alternatives
rely on natural fate and transport processes
and treatability
prior to implamen
and 5 to obtain d
the dredging, CDF
within the r
protective l
Twelvemile C
alternatives
control stru
protectivene
years. Alte
achieves pro
Lake Hartwel
lake area) i
5 years) tha
costly alter
Implementabi
would be the
Alternatives
close coordi
and other ag
administrati
with these a
manageable.
to implement
and technica
Alternatives
Cost - Costs
provided und
section of t
State Accept
Carolina is
Plan. The S
Alternative
should be se
final select
the public c
State will r
selection of
Community Ac
this Propose
is to encour
the remedy s
acceptance o
be evaluated after the public comment period
and will be described in the Record of
Decision for the Site.
EPA'S PREFERRED ALTERNATIVE
maximum exten
remedy does n
treatment as a princ
excessive costs. Ba
received from the pu
comment
In summary, based upon the information
available at this time, EPA is proposing
Alternative 2B - Fisheries Isolation, which
also includes those activities described under
Alternative 2A. Placement of the fish fence
in the vicinity of the Hwy 37 Bridge would
result in isolation of the Twelvemile Creeks
Keowee River and upper Seneca River
Arms, which represent less than 10 pacent
of the total area of Lake Hartwell Isolation
of these upstream areas is expectd to result
in an accelerated decline in migratory fish
PCB concentrations in the downstream
portions of the reservoir (i.e. the remaining
90+ percent of the lake). Migratory species
represent approximate 50% of the fish
harvested by weight from Lake Hartwell
Reduction of fish PCB levels would allow
for rescinding of the existing fish advisories
in these areas, returning the majority of lake
areas to normal use. This approach is
consistent in the COE's Best Management
Practices for Lake Hartwell, designed to
achieve the maximum beneficial uses for the
reservoir, which include fish and wildlife
management and recreational use.
period, EPA, in clos
COE and SCDHEC, may
preferred alt
remedial alte
Proposed Plan
Alternative 2B - Fisheries Isolation
represents the best balance among the
criteria used to evaluate the other
alternatives. Alternative 2B is believed to be
protective of human health and the
environment, would attain ARARs, would be
cost effective and would utilize permanent
solutions and resource technologies to the
COMMUNITY PAR
Concurrent wi
Plan, EPA has
comment perio
through May 1
written and o
Plan and all
located in th
below. All c
should be dir
Remedial Proj
OU2 Site, at
number listed
EPA will exte
by 30 additio
public meetin
1994 to prese
the RI/FS Rep
rationale beh
Altanative 2B
meeting will
located at th
Hwy 123 in Cl
Representativ
Corps of Engi
Department of
Control will
questions the
future activi
GLOSSARY
Administrative Record - A file which contains all
information used by the EPA to make its decision on
the selection of a response action under CERCLA.
Parts Per B
Units
of contamin
This file is required to be available for public review
million oun
in 1
and a copy is to be established at or near the site,
PCB's are m
usually at the information repository. A duplicate file
pool, the w
is maintained in a central location such as a regional
EPA and/or state office.
Polychlorinated Biphenyls
family of
organic compounds used since
1926 in electric
Baseline Risk Assessment - An assessment which
transformer
lubricants,
provides an evaluation of the potential risk to human
carbo
health and the environment in the absence of remedial
compo
action.
proce
environment because they do no
break down.
Comprehensive Environmental Response,
PCBs are st
Compensation and Liability Act (CERCLA)animals through the
biaccumulation process. EPA
A federal law passed in 1980 and modified in 1986
banne
by the Superfund Amendments and Reauthorization
are not
although
Act (SARA). The Act created a trust fund, known as
acute
Superfund to investigate and clean up abandoned or
PCBs
uncontrolled hazardous waste sites.
Remed
Hazard Ranking System - A scoring system used by
Two d
EPA to evaluate relative risks to public health and the
toget
environment. A score is calculated based on actual or
conta
potential release of hazardous substances through all
sitemedia present (i.e. the air, soils, surface water,
sediments, groundwater). If a site scores above 28.5,
Recor
the site is proposed for inclusion of the National
expla
Priorities List.
Natio
choos
Information Repository - Materials on Superfund
possi
and a specific site located conveniently for local
residents.
Super
(SARA
Macroinvertebrates - Small animals lacking
Octob
backbones found in sediments of water bodies.
National Contingency Plan - The Federal regulation
that guides the Superfund program.
National Priorities List (NPL) - EPA's list of
uncontrolled or abandoned hazardous wastes sites
eligible for long-term cleanup under the Superfund
Remedial Program.
FOR MORE INFORMATION CONTACT:
Remedial Project Managers
Operable Unit Two - Craig Zeller
Operable Unit One - Bernie Hayes
Community Relations Coordinator
Cynthia Peurifoy
AT
U S. Environmental Protection Agency - Region IV
North Superfund Ramedial Branch
345 Courtland Street, N.E., Atlanta, GA 30365
1-(800) 435-9233, or (404) 347-7791
**************************
C. Michael Alexander
Savannah District Fishies Biologist
U.S. Army Corps of Engineers
Richard B. Russell Lake
4144 Russell Dam Drive
Elberton, GA 30635
(706) 283-8731
**********************
Richard Haynes, District Engineer
South Carolina Department of Health & Enviromental Control
2600 Bull Street, Columbia, South Carolina 29201
(803) 734-5487
INFORMATION REPOSITORIES
The Administrative Record for the Sangamo Site is available for review a
The Village Library
Main Street
Pickens, SC 29671
(803) 859-9679
Pickens Coun
Easley Branc
110 West Fir
Easley, SC 2
(803) 859-96
R. M. Cooper Library
Clemson University
Clemson, SC 29634-3001
(803) 656-5174
Hart County
Benson Stree
Hartwell, GA
(706) 376-46
Lake
<IMG SRC 04941783>
<IMG SRC 04941784>
U S. Army Corps of Engineers
Hartwell Natural Resources Management Center
Hartwell, Georgia
(706)376-4788
<IMG SRC 04941785>
<IMG SRC
04941786>
<IMG SRC 04941787>
<IMG SRC 04941788>
<IMG SRC 04941789>
Table 1
Estimated Time Required to Achieve Protectiveness
Sangamo OU-2 FS
TIME FOR FISH TO ATTAIN FDA LFVEL
PROTECTIVENESS(4)
(yrs)
TIME TO
IMPLEMENT(1)
ALT.
TWELVEMILE
CREEK/SENECA
MAIN BODY OF
BODY OF
NO.
HARTWELL LAKE
1
2A
2B
3A
3B
3C
4
5
DESCRIPTION
(yrs)
No action
0
Institutional Control
0.5
Fisheries Isolation
1
Capping
2
Sediment Control Structure 2
Optimal Capping/Sediment
2-3
Control Structure
Confined Disposal Facility 3-4
Stabilization
4-5
RIVER(2) ARM
HARTWELL LAKE(3
12
12
12
3-4
12
3-4 (downstream)
12 (upstream)
5-6
5-6
12
12
3-4
3-4
3-4
3-4
5-6
5-6
NOTE: (1) Includes time needed for pre-design studies, design, procure
include time between Proposed Plan/Record of Decision Initiation of Remedial
Design.
(2) Twelvemile Creek Arm only; FGETS modeling results indicate t
level (2 mg/kg) in approximately 12 years under baseline conditions; none
of the alternatives will extend the period required for this
period to achieve protectiveness of greater than 12 yrs).
(3) Downgradient of the Twelvemile Creek Arm (i.e., main body of
decline more rapidly for actions involving isolation, capping or removal of
contamainted sediment (Alternatives 2B, 3A-C, 4 and 5). It
comparable to that observed in the Twelvemile Creek Arm for Alternatives
involving capping (3-4 yrs) or removal of the sediment (5-6
estimate.
(4) Duration only; based on estimated time to implement remedy a
levels to decline to FDA level, based on the FGETS modeling results
presented in Section 3.3 and assumptions regarding migratory
USE THIS SPACE TO WRITE YOUR COMMENTS
Your input on the Proposed Plan for the Sangamo Superfund Site - OU2 i
helping EPA select a final remedy for the site. You may use the spac
your comment, then fold and mail. A response to your comment will be
________________________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
______________________________________________________________________
REQUEST TO BE PLACED ON THE SANGAMO WESTON, INC./TWELVE MILE CREEK/LAKE
HARTWELL SITE MAILING LIST
If you would like to be placed on the mailing list for the Sangamo Sit
this form and return to: Cynthia Peurifoy, Community Relations Coordi
IV, North Superfund Remedial Branch, 345 Courtland Street, Atlanta, Ge
call 1-800-435-9233.
NAME:___________________________________________________________________________
ADDRESS:________________________________________________________________________
______________________________________________________________________
TELEPHONE:______________________________________________________________________
AFFILIATION:____________________________________________________________________