Health Consultation
Varney Pond: Stormwater Settling Pond
Sediments
WHITE BEAR LAKE, RAMSEY COUNTY, MINNESOTA
DECEMBER 16, 2011
Prepared by:
The Minnesota Department of Health
Environmental Health Division
Under Cooperative Agreement with the
Agency for Toxic Substances and Disease Registry (ATSDR)
U.S. Department of Health and Human Services
This document has not been reviewed or cleared with ATSDR
FOREWORD
This document summarizes public health concerns related to disposition of contaminated
dredged sediments in Minnesota. It is based on a formal site evaluation prepared by the
Minnesota Department of Health (MDH). For a formal site evaluation, a number of steps are
necessary:

Evaluating exposure: MDH scientists begin by reviewing available information about
environmental conditions at the site. The first task is to find out how much contamination is
present, where it is found on the site, and how people might be exposed to it. Usually, MDH
does not collect its own environmental sampling data. Rather, MDH relies on information
provided by the Minnesota Pollution Control Agency (MPCA), the US Environmental
Protection Agency (EPA), and other government agencies, private businesses, and the
general public.

Evaluating health effects: If there is evidence that people are being exposed—or could be
exposed—to hazardous substances, MDH scientists will take steps to determine whether that
exposure could be harmful to human health. MDH’s report focuses on public health— that is,
the health impact on the community as a whole. The report is based on existing scientific
information.

Developing recommendations: In the evaluation report, MDH outlines its conclusions
regarding any potential health threat posed by a site and offers recommendations for reducing
or eliminating human exposure to pollutants. The role of MDH is primarily advisory. For that
reason, the evaluation report will typically recommend actions to be taken by other agencies—
including EPA and MPCA. If, however, an immediate health threat exists, MDH will issue a
public health advisory to warn people of the danger and will work to resolve the problem.

Soliciting community input: Generally, the evaluation process is interactive. MDH starts by
soliciting and evaluating information from various government agencies, the individuals or
organizations responsible for the site, and community members living near the site. Any
conclusions about the site are shared with the individuals, groups, and organizations that
provided the information. Once an evaluation report has been prepared, MDH seeks feedback
from the public. If you have questions or comments about this report, we encourage you to
contact us.
Please write to:
Community Relations Coordinator
Site Assessment and Consultation Unit
Minnesota Department of Health
625 North Robert Street
PO Box 64975
St. Paul, MN 55164-0975
Or call us at:
(651) 201-4897 or 1-800-657-3908
(toll free call - press "4" on your touch tone phone)
On the web:
http://www.health.state.mn.us/divs/eh/hazardous/index.html
ii
TABLE OF CONTENTS
TABLE OF CONTENTS ............................................................................................................ iii Tables ............................................................................................................................................. iv Figures ........................................................................................................................................... iv List of Acronyms............................................................................................................................ v I. Introduction ................................................................................................................................ 1 II. Background and Site History .................................................................................................. 2 A. Stormwater Settling Ponds ...................................................................................................... 2 1. General Information ............................................................................................................ 2 2. Chemical Contaminants in Stormwater Settling Pond Sediments ...................................... 2 B. Varney Pond ............................................................................................................................ 3 1. General Information ............................................................................................................ 3 2. Sediment Data ..................................................................................................................... 4 III. Chemical of Interest: Polycyclic Aromatic Hydrocarbons ................................................. 5 A. Evaluating the carcinogenic potency of environmental PAH mixtures .................................. 5 1. B[a]P potency ...................................................................................................................... 6 2. Estimating the cPAH potency of a mixture using a whole mixture potency approach ....... 7 3. Estimating the cPAH potency of a mixture by addition of individual cPAH potencies ..... 7 B. Analytical and cost considerations for cPAH analyses ........................................................... 8 C. Estimating the cPAH potency of land-applied Varney Pond Sediments ................................ 9 1. Application of a whole mixture potency analysis to Varney Pond ..................................... 9 2. Application of B[a]P PEQ analyses to Varney Pond ........................................................ 11 3. Uncertainties and data gaps; and information that could decrease uncertainty and increase
confidence in risk estimates................................................................................................... 11 B[a]P Cancer Slope Factor............................................................................................... 11 Adjustment of lifetime B[a]P CSF for early-life sensitivity during less-than-life exposures
........................................................................................................................................... 11 What happens when or if the US EPA draft Relative Potency Guidance is approved? .... 12 Validation of relative potency or potency equivalence approach for evaluating PAH
cancer potency ................................................................................................................... 12 Would additional data from Varney Pond result in a better potency evaluation? ............ 13 IV. Conclusions ............................................................................................................................ 13 V. Recommendations ................................................................................................................... 15 VI. Public Health Action Plan .................................................................................................... 15 VII. References ............................................................................................................................ 16 Preparers of the Report: ............................................................................................................. 18 CERTIFICATION ...................................................................................................................... 18 iii
Tables
Table 1: Sediment Contaminant Data (dry weight) ......................................................................... 4 Table 2: Varney Pond Sediment PAHs Analyzed, Required US EPA PAH18, PEFMDH and Draft
RPFEPA ................................................................................................................................. 6 Table 3: Correlations between PAHs in Coal Tar and Sediment Data.......................................... 10 Figures
Figure 1: Aerial View of Varney Pond............................................................................................ 3 Figure 2: Fingerprint comparison (15 PAHs) of Coal Tar Mixtures and Settling Pond Sediment
Data.................................................................................................................................... 10 iv
List of Acronyms
B[a]P
B[a]P PEQMDH
B[a]P PEQmix
B[a]Pmix
Ci
cPAH(s)
cPAH25
cPAH7
CSF
CSF33yr
CSF70yr
CSFB[a]P
CSFmix
CT
EU
MDH
MN
MPCA
MS4
NPDES/SDS
NTP
OEHHA
PAH(s)
PEF(s)
PEFi
PEFMDH
PEQ(s)
PHG
QA/QC
RPF
RPFEPA
SRV(s)
SSV(s)
US EPA
US EPA IRIS
US EPA PAH18
benzo[a]pyrene
total B[a]P potency equivalence for all analyzed cPAHs from the MDH
cPAH list
whole mixture B[a]P potency equivalence
concentration of B[a]P in a mixture
sample concentration of a single cPAH (cPAHi)
carcinogenic PAH(s)
25 cPAHs recommended by MDH for analysis
7 cPAHs historically recommended by US EPA for analysis
cancer slope factor
human cancer slope factor averaged over a 33 year exposure period
human cancer slope factor averaged over a 70 year exposure period
cancer slope factor for benzo[a]pyrene
cancer slope factor for a whole mixture
coal tar
European Union
Minnesota Department of Health
Minnesota
Minnesota Pollution Control Agency
Municipal Separate Storm Sewer System
National Pollutant Discharge Ellimination System/State Disposal System
National Toxicology Program, National Institute of Environmental
Health Sciences
Office of Environment Health Hazard Assessment, California
polycyclic aromatic hydrocarbon(s)
potency equivalence factor(s)
MDH PEF for a single cPAH (cPAHi)
MDH recommended cPAH PEFs
potency equivalence(s)
Public Health Guidance
quality assurance/quality control
relative potency factor
US EPA Draft RPFs
MPCA Soil Reference Value(s)
MDH Sediment Screening Value(s)
United States Environmental Protection Agency
US EPA Integrated Risk Information System
18 PAHs historically recommended by US EPA for analysis
v
I. Introduction
Stormwater settling ponds are used to control storm event runoff, to act as settling basins to
collect sediment and contaminants, and keep sediment and contaminants from entering areas
where they may adversely impact the environment. In November 2010, the Minnesota Pollution
Control Agency (MPCA) informed the Minnesota Department of Health (MDH) that a large
number of stormwater settling ponds in Minnesota are in need of dredging, and that
contamination of the sediments requires transport of the dredged spoils to lined landfills.
Transportation and tipping fees makes this remediation extremely expensive. Therefore, the city
of White Bear Lake, Minnesota developed preliminary plans for non-traditional remediation of
Varney Pond as a possible model for on-site storage of contaminated stormwater settling pond
sediments. The proposed remedy is to dredge the sediments from a stormwater settling pond and
use it to construct a berm adjacent to the settling pond. Depending on the level of contamination,
sediments would either be buried or would be applied to the surface of the berm. Varney Pond
contamination is primarily a large class of chemicals, called polycyclic aromatic hydrocarbons
(PAHs), that are byproducts of fossil fuel combustion. While shortterm dermal exposures to
PAHs can irritate the skin, the health outcome of primary concern for people exposed to PAHs is
cancer.
On-site remediation would place Varney Pond dredged sediments in a berm constructed adjacent
to the stormwater settling pond. The sediments with the greatest contamination would be deep in
the proposed berm, with lesser contaminated sediments nearer to the surface. The berm would
be covered with topsoil or sediments that have contaminant concentrations below the MPCA Soil
Reference Values (SRVs). Because some of the sediments may be used near the surface of the
berm or as topsoil, there is the potential for public exposure similar to exposures to contaminants
in soil. MDH generally supports the use of the SRVsfor evaluating soil exposure hazard and
risk. The SRVs are contaminant concentrations that the MPCA has determined are appropriately
protective of people exposed to those soils. SRVs incorporate information about the toxicity of
contaminants as well as reasonable potential exposure information. There are only limited data
available on the sediment contamination in Varney Pond – many important carcinogenic PAHs
(cPAHs) were not analyzed. Therefore, the cancer potency of the sediments is unknown and
direct application of the cPAH SRV may not be protective.
In this Health Consultation, MDH discusses using surrogate whole mixture toxicity methods and
PAH fingerprint methods to estimate the cancer potency of Varney Pond sediments. In addition,
the document includes discussion of uncertainties of the data and uncertainties of the methods
used to analyze the data. Despite the uncertainties, MDH believes that it is possible to develop a
reasonable health protective potency estimate that can be incorporated with MPCA SRV
exposure estimates to develop site-specific, protective soil criteria for dredged sediments from
Varney Pond.
This document does not discuss potential risks that may be associated with exposure to in-place
sediments or indirect exposure by consumption of fish from Varney Pond. Evaluation of inplace sediments would require analytical data on additional potential contaminants and
evaluation of different exposure scenarios as well.
1
II. Background and Site History
A. Stormwater Settling Ponds
1. General Information
Municipal stormwater ponds are intended to minimize the amount of material and contaminants
reaching natural waterways during stormwater runoff events. They act as buffers, slowing the
movement of stormwater; allowing material to settle out; and releasing cleaner water
downstream to streams and rivers. Stormwater settling ponds accumulate contaminants and may
be unsafe for recreational activities.
Municipal stormwater ponds are regulated by the MPCA under the National Pollutant Discharge
Ellimination System/State Disposal System (NPDES/SDS) Municipal Separate Storm Sewer
System (MS4) Permit Program. Municipalities are required to annually inspect 20% of all
stormwater ponds that they operate.
As a result of collecting particulates and other material from watersheds during storm events,
retention ponds eventually fill in and need to be dredged. Because the pond sediments contain
contaminants, exposure to these dredged materials may result in adverse impacts to health or the
environment. Disposal alternatives are reviewed with consideration given to the potential
environmental impacts, the potential for human exposure, and the toxicity of the dredged
materials.
Public exposure to settling pond sediments in this Varney Pond evaluation, is only assumed to
occur when the sediments are dredged and deposited on land. When this occurs, exposure
pathways are equivalent to soil exposure pathways, and risks are evaluated as exposures to
contaminants in soil. Therefore, comparison of stormwater sediment contamination and MPCA
soil reference values (SRVs) are appropriate. Stormwater settling ponds cannot be assumed to
be safe for recreation due to the potential exposure to contamination in the sediments. Use of
SRVs for evaluation of health risks from sediments in situ is not appropriate. Exposure to
sediment contaminants in situ may be much greater than exposures to contaminants in soil due to
mixing of sediments in the water column, and the potential for ingestion of suspended sediments,
dermal exposures, exposures to dissolved contaminants, and indirect exposure by consumption
of fish that may have accumulated contaminants. This document does not consider in situ
exposures.
2. Chemical Contaminants in Stormwater Settling Pond Sediments
Heavy metals and polycyclic aromatic hydrocarbons (PAHs) are typically the contaminants of
most concern in stormwater settling ponds. However, if there are specific potential sources of
contamination (e.g. agricultural or industrial chemicals) near a settling pond, additional
chemicals may need to be considered.
Heavy metals that may be found in settling pond sediments include chromium, lead, zinc,
arsenic, copper, and silver. Historically, lead levels in stormwater settling pond sediments were
well above background levels because of the use of leaded gasoline in motor vehicles. However,
with the curtailment of use in the 1980s, lead levels in stormwater settling ponds have decreased
significantly.
2
PAH concentrations may be substantially elevated above background levels in stormwater pond
sediments. This is presumed to be because PAHs are a component of asphalt and pavement
treatments, motor vehicle exhaust, home, commercial and industrial heating exhaust, incinerator
emissions and emissions from any form of fossil fuel combustion.
B. Varney Pond
1. General Information
Varney Pond, in urban White Bear Lake (Figure 1), was constructed to act as a stormwater
retention pond (stormwater settling pond) after a large storm in 1980 resulted in significant
erosion and localized flooding (Donald Berger, MPCA, personal communication, October 25,
2011). Varney Pond covers about 62,000 square meters. White Bear Lake has a population of
about 24,325 (2000 census). Access to Varney Pond, or the city-owned land around it, is not
restricted. Numerous residential yards back up on the Pond. Apparently, some residents have
docks and boats in the Pond. White Bear Lake Area High School, South Campus, is north and
northeast of Varney Pond. The Minnesota County Well Index (Ramsey County) shows 3 wells
within 500 meters of the Pond. It is not known if these wells are actively used, as city water is
available to residents and businesses.
Figure 1: Aerial View of Varney Pond
http://services.arcgisonline.com/arcgis/services
Private wells – Ramsey County Well Index
3
2. Sediment Data
In 2008 Braun Intertec evaluated the sediments in Varney Pond for the City of White Bear Lake
(Braun Intertec, 2008). The pond was evaluated because it had been selected for improvement –
restoration of pond capacity and water quality improvement. In the spring of 2008, a total of 7
sediment samples were taken from the pond and analyzed for contaminants: 19 polynuclear
aromatic hydrocarbons (PAHs), including 7 carcinogenic PAHs (cPAH7); total arsenic; and total
copper (see Attachment 1). PAH data in Table 1 are in units of benzo[a]pyrene potency
equivalents (B[a]P PEQ) which is a measure of cancer potency of a mixture of PAHs obtained by
adding potency equivalents for individual PAHs (see “Evaluating the carcinogenic potency of
environmental PAH mixtures” below). Table 1 also includes MPCA residential (Level 1) and
industrial (Level 2) Soil Reference Values (SRVs) for arsenic, copper and PAHs (B[a]P). The
PAH SRVs are based on the potency of B[a]P and can be used to evaluate cPAHs whose potency
has been normalized to B[a]P PEQs. In accordance with MDH recommendations
(http://www.health.state.mn.us/divs/eh/risk/guidance/pahmemo.html), MPCA (MPCA, 2011)
recommends evaluating 25 cPAHs at:


Sites where stormwater pond sediments are being characterized for potential reuse. These sediments may contain extended list cPAHs due to the prevalence of coal‐tar based products used to seal coat parking lots and other paved surfaces; Sites where a formal human health risk assessment is being conducted in response to cPAHs being identified as a contaminant of concern, or sites where extended list cPAHs have been previously identified. In these situations, it is recommended that MPCA and/or MDH risk assessment staff be consulted to determine if analysis of the extended list of cPAHs is necessary. Table 1: Sediment Contaminant Data (dry weight)
Location
Sample #
Varney Pond
1
1
2
3
3
4
4
Sample
PAHs
Arsenic Copper
Depth
(B[a]P PEQ
(mg/kg) (mg/kg)
(feet)
- mg/kg)
0-2
2-4
0-2
0-2
2-4
0-2
2-4
<1.1
1.5
0.98
1.9
1.6
1.2
<1.3
19
11
28
22
12
15
15
5.8 *¥
0.5 *¥
1.6 *¥
7.3 *
3.7 *
6.7 *
4.8 *
(data from Braun Spreadsheet - BL-08-00749 0801278 - Varney Data (raw ); Attachment 1)
MPCA Soil
Residential †
Reference Values Industrial ‡
9
100
2¤
20
9000 §
3¤
* B[a]P PEQ analysis limited to 7 cPAHs (shaded in Table 2, below)
¥ Failed QA/QC (Matrix Spike or Duplicate Matrix Spike Recovery)
† http://www.pca.state.mn.us/index.php/view-document.html?gid=3153
‡ http://www.pca.state.mn.us/index.php/view-document.html?gid=3154
§ not protective of shortterm exposure
¤ B[a]P PEQ evaluation based on sample analysis for 25 cPAHs (see below)
Data from the Varney Pond suggest arsenic and copper levels in these sediments are similar to
typical Minnesota soil background levels (Boerngen and Shacklette, 1981). If dredged sediments
are applied to soil, MPCA residential and industrial SRVs for arsenic and copper should not be
4
exceeded. However, all 4 PAH samples (passing laboratory QA/QC) exceeded the residential
and industrial B[a]P PEQMDH SRV. In addition, note that only 7 of the recommended 25
recommended cPAHs were analyzed in each sample. Therefore the B[a]P PEQs from Varney
Pond sediment data are likely biased low.
III. Chemical of Interest: Polycyclic Aromatic Hydrocarbons
A. Evaluating the carcinogenic potency of environmental PAH
mixtures
PAHs in the environment are always found in mixtures. Whole mixture potency information
from human epidemiological studies or animal studies should provide the best cancer potency
estimates (US EPA, 2002; 2010). Site or source-specific mixture potency data are not available
for stormwater pond sediments or for Varney Pond sediments. If experimental or
epidemiological potency data are not available for a site-specific mixture, the potency of a
similar, surrogate mixture may provide a reasonable estimate of the potency of the mixture of
interest. However, environmental mixtures of PAHs vary greatly across different source types
and individual sources, and cancer potency data are not available for most environmental PAH
mixtures. As a result, a third method may also be used. This method estimates the combined
potency of different cPAHs (carcinogenic PAHs) in a mixture by multiplying the concentration
of each individual cPAH by its potency, converting the result to a standard metric (a B[a]P
equivalent; B[a]P PEQ) and adding the results. Relative potency factors (RPFs) for cPAHs,
sometimes called potency equivalent factors (PEFs) are shown in Table 2.
MDH recommends calculating B[a]P PEQs using the following equation:
B[a]P PEQMDH = Σ(Ci * PEFi)
Where:
for i = each of 25 cPAHs with
a cPAH PEFMDH
Equation 1.
Ci = the sample concentration for a cPAH compound (mg/kg)
PEFi = the MDH preferred Potency Equivalence Factor (PEFMDH) for each cPAH
compound (Table 2)
The US EPA (2010) utilizes a similar approach for calculating a cancer risk estimate from (draft)
relative potency factors (RPFEPA). RPFEPA are used to scale potency of 24 non-heterocyclic,
non-alkylated cPAHs to the potency of B[a]P, the index cPAH.
5
Table 2: Varney Pond Sediment PAHs Analyzed, Required US EPA PAH18,
PEFMDH and Draft RPFEPA
PAH
Acenaphthene
Acenaphthylene
Anthanthrene
Anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo[c]fluorene
Benzo(e)pyrene
Benzo(g,h,i)perylene
Benzo(j)fluoranthene
Benzo(k)fluoranthene
Benz(a)anthracene
11H-Benz[b,c]aceanthrylene
Benz[e]aceanthrylene
Benz[j]aceanthryIene
Benz[l]aceanthrylene
Carbazole
Chrysene
Cyclopenta[c,d]pyrene
4H-Cyclopenta[d,e,f|chrysene
Dibenzo(a,h)anthracene
Dibenzofuran
Dibenz[a,h]acridine
Dibenz[a,j]acridine
cPAHs - cPAHs - EPA
B[a]P Draft B[a]P
PEFMDH †
RPFEPA§
Varney
Pond*
EPA18
X
X
X
X
X
X
X
X
1
1
X
X
0.1
0.8
‡
PAH
0.4
20
X
X
0.009
X
0.1
0.3
X
X
0.1
0.03
X
X
0.1
0.2
0.05
0.8
60
5
X
X
X
0.01
0.1
0.4
0.3
X
X
0.6
X
0.1
0.1
10
PAH
Dibenzo[a,e]fluoranthene
Dibenzo[a,e]pyrene
Dibenzo[a,h]pyrene
Dibenzo[a,i]pyrene
Dibenzo[a,l]pyrene
7H-Dibenzo[c,g]carbazole
7,12-Dimethylbenz[a]anthracene
1,6-Dinitropyrene
1,8-Dinitropyrene
Fluoranthene
Fluorene
Indeno(1,2,3-c,d)pyrene
3-Methylcholanthrene
5-Methylchrysene
2-Methylnaphthalene
Naphthalene
Naphtho[2,3-e]pyrene
5-Nitroacenaphthene
6-Nitrochrysene
2-Nitrofluorene
1-Nitropyrene
4-Nitropyrene
Phenanthrene
Pyrene
Varney
Pond*
EPA18
‡
PAH
cPAHs - EPA
B[a]P
† Draft B[a]P
PEFMDH
RPFEPA§
0.9
1
0.4
10
0.9
10
0.6
10
30
1
30
10
1
X
X
X
X
X
X
0.08
0.1
0.07
3
1
X
X
X
X
0.3
0.02
10
0.01
0.1
0.1
X
X
X
X
Shaded cells show cPAHs analytes for Varney Pond data (Braun Intertec, 2008)
* Varney Pond PAH data in Attachment 1
‡ Required US EPA PAH analytes, used since the 1980s to characterize contaminated
soils
† MDH recommended B[a]P potency equivalent factors
http://www.health.state.mn.us/divs/eh/risk/guidance/pahmemo.html
§ Draft US EPA B[a]P relative potency factors
http://oaspub.epa.gov/eims/eimscomm.getfile?p_download_id=494851
B[a]P potency, and both the whole mixture and PEQ evaluations adding potencies of individual
cPAHs (i.e. PEFs) found in mixture are described in further detail below. Their application to
Varney Pond sediment data is also described.
1. B[a]P potency
Relative cancer potency for cPAHs other than B[a]P are typically determined in studies that also
test B[a]P potency. As a result, individual cPAH potencies can be normalized to B[a]P, and
PEFs can be easily calculated. This makes it easy to compare different studies with different
exposures or compare studies in species with different sensitivities. Because all cPAH potency
studies are normalized to B[a]P, adjustments or use of alternative B[a]P potency estimates will
not only change the B[a]P potency, but will also impact the estimated potency of other cPAHs.
6
Three different cancer slope factors (CSFs) are generally used to quantify the potency of B[a]P.
US EPA Integrated Risk Information System (US EPA IRIS;
http://www.epa.gov/iris/subst/0136.htm) recommends an oral CSF of 7.3 (mg/kg/d)-1 based on
the geometric mean of studies last reviewed November, 1994. This value was used to develop
the MDH Multimedia Health Risk Value for B[a]P (MDH, 2001), and in the MPCA SRVs
http://www.pca.state.mn.us/index.php/waste/waste-and-cleanup/cleanup-programs-andtopics/topics/risk-based-site-evaluation-process-guidance-documents.html?menuid=&redirect=1.
California’s Office of Health Hazard Assessment (OEHHA) Hot Spots Program (CA OEHHA,
2009) recommends an oral CSF of 12(mg/kg/d)-1 developed in 1993 from a 1967 study by Neal
and Rigdon. Recently, California OEHHA Public Health Goal (PHG) evaluation of drinking
water developed a CSF of 1.7 (mg/kg/d)-1 based on a study by Culp et al. (1998) (CA OEHHA,
2010).
MDH, along with the US EPA and other public health agencies in the United States, recognizes
that children are more sensitive to carcinogens than adults. MDH has developed guidance for the
application of an early-life sensitivity adjustment to cancer risk evaluations
(http://www.health.state.mn.us/divs/eh/risk/guidance/adafrecmd.pdf ). None of the CSFs cited
above contain an early-life sensitivity adjustment, although the final OEHHA PHG for drinking
water does incorporate a factor of 1.7 as an early-life sensitivity adjustment applied to 70 years
of exposure (resulting in a final CSF of 2.9 (mg/kg/d)-1). Early-life exposures to soils are also
greater than those later in life. Therefore, final B[a]P and B[a]P PEQ exposure guidance should
include early-life sensitivity adjustments that are matched with early-life exposure estimates.
2. Estimating the cPAH potency of a mixture using a whole mixture potency
approach
If appropriate data are available, MDH recommends using the cancer potency of a whole
environmental PAH mixture (or a reasonable surrogate mixture) when assessing risk. Two types
of information are necessary to apply a whole mixture potency approach:
1) The cancer potency of the mixture or surrogate must be available.
2) Fingerprints of the toxicity tested mixture and mixture of interest should be similar, with
the mixtures being from the same source or source type.
With mixtures having similar fingerprints, a common index PAH (typically B[a]P) is chosen and
the potency of the comparable whole mixture can be determined relative to the B[a]P
concentration. The potency of individual environmental samples can be calculated using
potency of the whole mixture and the B[a]P concentration in each sample.
Where:
B[a]P PEQmix = B[a]Pmix x CSFmix / CSFB[a]P
Equation 2.
B[a]P PEQmix is the B[a]P concentration (mg/kg) that is estimated to have equal cancer
potency as the cancer potency of the total mixture.
B[a]Pmix is the concentration of B[a]P in the sample.
CSFmix, CSFB[a]P are cancer slope factors for the total mixture and B[a]P, respectively.
3. Estimating the cPAH potency of a mixture by addition of individual cPAH
potencies
MDH recommends using the cancer potency of a whole environmental PAH mixture (or a
reasonable surrogate) when assessing risk (as described above). However if these data are not
7
available, MDH recommends analyzing an extended list of cPAHs, and using the relative
potency of cPAHs analyzed (B[a]P PEFs) to determine a B[a]P PEQ as an estimate of mixture
potency (Equation 1).
Historically cPAH potency of a mixture has been estimated using the benzo[a]pyrene
concentration in a mixture, the sum of the concentrations of the 7 cPAHs (cPAH7) typically
analyzed in the US EPA recommended suite of 18 PAHs, or a sum of the potency equivalents of
the cPAH7. These estimates have resulted in an underestimation of the potency of cPAHs in a
mixture (US EPA, 2010).
The World Health Organization (IARC, 2010) discusses the importance of considering potent
carcinogens when evaluating cPAH risk.
“Although benzo[a]pyrene is the marker of PAH exposure that is most often used, there
is evidence that a few PAH congeners, for example, dibenzo[a,l]pyrene, are more potent
in their ability to induce lung cancer or skin cancer in experimental systems. These
potent congeners should be measured in environmental and biological samples, as they
may contribute substantially to the risk of human cancer attributable to PAH mixtures.”
B[a]P is the most potent cPAH7, whereas there are numerous PEFMDH and RPFEPAwith potencies
greater than B[a]P (see Table 2). While the cPAH7 have been recommended for analyses by the
US EPA since the 1980s, analysis of an additional 18 cPAHs (cPAH25) has been generally
recommended since 2002 by MDH and MPCA (MPCA, 2002; 2011). Note the US EPA is in the
process of revising and expanding their list of cPAHs to include many cPAHs on the MDH list.
In total, the US EPA Draft Proposed Guidance (US EPA, 2010) identifies 24 non-heterocyclic
and non-alkylated cPAHs (draft RPFEPA); 12 of these are additional cPAHs, are not evaluated
using current MDH Guidance.
B. Analytical and cost considerations for cPAH analyses
cPAH potency is likely underestimated for environmental mixtures when the analysis is limited
to cPAH7. Therefore, using cPAH7 data to evaluate the cancer potency of a PAH mixture is not
likely to be health protective. Chemical analyses of additional cPAHs beyond cPAH7 are not
typically performed in analytical laboratories, nor are there US EPA approved methods for
analysis of all identified cPAHs. Some commercial laboratories in the US and Canada analyze
an extended list of cPAHs with mixed success (see MDH, 2006 for an example of problems
encountered). Laboratory quality assurance and quality control (QA/QC) are important, as is
splitting samples between different laboratories to assure acceptable cPAH data. The MDH
Public Health Laboratory and a number of laboratories in the European Union (EU) appear to
have developed methods for many of the important analytes. EU labs have developed methods
capable of detection as low as 0.1 parts per billion (ppb) for many cPAHs found in food. This
detection limit is sufficiently low for analyzing cPAHs in sediments or soil. Analytes detected
using these methods include benzo[c]fluorene, and the dibenzopyrenes that appear to be some of
the most potent cPAHs; presently, benzo[c]fluorene is not included in MDH’s recommended list
of 25 cPAHs.
Individual PAH sources have PAH signatures, also called fingerprints, that can be used to
determine individual source contributions to PAH mixtures found in a local environment (one
technique reviewed in Wang et al., 1999). Analyses of only a few samples of a known source
8
can be used to identify the signature of the source, and to develop a B[a]P PEQ : B[a]P ratio
from Equation 1. Note, from Equation 2, B[a]P PEQmix / B[a]P = CSFmix / CSFB[a]P which is the
relative potency of the mixture to the potency of B[a]P. For each sample from the same known
source, the concentration of B[a]P and relative potency of the mixture are entered into Equation
2, and the resulting B[a]P PEQ is the potency of the individual sample in B[a]P equivalents.
Using this technique, only a few samples in a given area need to be analyzed for a long list of
cPAHs - using more difficult and costly methods. Yet if PAH mixture homogeneity can be
shown, the extent and the magnitude of the contamination throughout the site can be determined
by applying the fingerprint to many samples with limited PAH analytical data from across the
site.
C. Estimating the cPAH potency of land-applied Varney Pond
Sediments
1. Application of a whole mixture potency analysis to Varney Pond
Recent nationwide research of 50 lakes by the US Geological Survey determined that coal tarbased sealant dust was the most important source of PAHs in lake sediments, especially east of
the Rockies (Van Metre and Mahler, 2010). MPCA analysis of the Varney Pond sediment data
suggests that about 70% of the PAH fingerprint is from coal tar dust and coal tar scrapings based
on the source profiles used by Van Metre and Mahler (Van Metre and Mahler, 2010) in the
EPA’s Contaminant Mass Balance model (Crane, 2011). However, due to the limited number of
PAHs measured in Varney Pond (which didn’t fully account for petrogenic and diagenic PAHs)
and QA/QC issues with the data, the percentage of PAHs attributable to coal tar-based sealants in
Varney Pond may be closer to 60%--this would be consistent with findings of a recent MPCA
metro-wide study of 15 stormwater pond sediments (Judy Crane, MPCA, personal
communication, October 28, 2011).
Cancer potency data on coal tar mixtures, calculated relative to the B[a]P concentration in the
mixture, are available from a National Toxicology Program (NTP) two-year chronic study with
B6C3F1 mice (Schneider et al., 2002). The upper limit cancer slope factor for ingested coal tar
(CSFCT) was calculated to be 11.5 (mg B[a]Pmix/kg/d)-1. Data from the same NTP study, for
B[a]P alone were used by different authors to calculate a CSF for B[a]P (CSFB[a]P). The CSFB[a]P
in this laboratory species (B6C3F1 mice) was calculated, using comparable methods, to be 1.2
(mg/kg/d)-1 (Gaylor et al., 2000). These data suggest that the cancer potency of coal tar in the
NTP study, measured in B[a]P PEQmix is 10 times more potent than B[a]P.
Coal tar from different sources, and coal tar that has been treated or weathered are likely to have
somewhat different signatures. Furthermore coal tar pitch, which is used in coal tar sealants, is a
product derived from coal tar by removing some coal tar volatiles. It is expected that there are
some differences between PAH signatures of these coal tar products, as well as between different
coal tar-based sealants.
In Figure 2, 15 PAHs analyzed in Varney Pond sediment and 2 additional stormwater settling
ponds in Minnesota are compared with the two mixtures of coal tar that were used in the NTP
mouse cancer study (Culp et al., 1998). Table 3 shows the correlation coefficients between the
plotted data sets. Note that the correlation between the 2 coal tar mixtures used by the NTP is
quite good (0.98), as is the correlation between the sediment pond data and Varney Pond data
9
(0.97). The correlations between the NTP data and the 2 groups of Minnesota data are not as
good (0.58 – 0.72). Some of the differences between coal tar and stormwater settling pond
sediments may be the result of weathering. The 4-6 ring PAH fractions of stormwater settling
pond sediments is considerably greater than the 4-6 ring PAH fraction found in coal tar (Figure 2
and Table 3) (fluoranthene, a 3-ring PAH, is also increased). This may suggest that the PAHs in
the sediment have weathered.
Figure 2: Fingerprint comparison (15 PAHs) of Coal Tar Mixtures and
Settling Pond Sediment Data
0.25
0.2
0.15
0.1
CT Mixture #1
0.05
CT Mixture #2
Varney Pond
0
Sediment Pond Data
CT (Coal Tar) Mixtures from Culp et al. (1998)
Sediment Pond Data: means of 12 samples from 2 ponds (source: MPCA PAH database)
Table 3: Correlations between PAHs in Coal Tar and Sediment Data
Coal Tar Mixture
#1
Coal Tar Mixture
#1
Coal Tar Mixture
#2
Varney Pond
Sediment
Stormwater
Sediment Pond
Data
Coal Tar Mixture
#2
Varney Pond
Sediment
Stormwater
Sediment Pond
Data
1
% 4-6 ring
PAHs
44%
0.98
1
0.69
0.72
1
0.58
0.62
0.97
48%
61%
1
65%
While Varney Pond and other analyzed Minnesota stormwater settling pond sediments are
similar, and while they have been generally characterized by the MPCA and the USGS as
containing a large fraction that is attributable to coal tar (or coal tar dust), their PAH signature
appears to be somewhat different than the coal tar mixtures that have been used to characterize
coal tar cancer potency. Weathering may account for some of this difference. However, due to
the lack of data on important cPAHs in both mixtures, it is not clear whether cPAHs in Varney
Pond sediments are more potent or less potent than cPAHs in coal tar. Use of a whole mixture
10
toxicity approach for characterizing Varney Pond data therefore has limitations. However, it still
may be a reasonable first estimate of the potency of PAHs in Varney Pond sediments. The
whole mixture approach suggests that the cancer potency of Varney Pond cPAHs is about 10
times the potency of the B[a]P sediment concentration.
2. Application of B[a]P PEQ analyses to Varney Pond
Seven cPAHs were analyzed in 2008 sediment samples from Varney Pond (see Table 2). The
mean B[a]P fraction of the total B[a]P PEQMDH from these data is 0.80, suggesting that the total
cPAH potency of the sediment mixture is 1.25 times (i.e. 1 / 0.8) the potency of B[a]P.
However, this is bias low, because many potent cPAHs were not analyzed in these samples.
While the limited set of cPAH sediment data from Varney Pond exceeded soil screening values,
further characterization of the magnitude of contamination is necessary to assure that disposal of
dredged sediment in soil is protective of public health. Analyses of additional cPAHs in Varney
Pond sediment samples would likely result in higher potency estimates and a greater calculated
risk to public health. Additional cPAH data are not available for Varney Pond, but it is
reasonable to use cPAH data from other settling ponds sediments as surrogate data if their PAH
fingerprints are similar to Varney Pond sediments.
MDH reviewed MPCA analytical data from 2 additional stormwater settling ponds in the Twin
Cities that appear to have similar total PAH fingerprints as Varney Pond PAH data (Figure 2).
PAH fingerprints of matching PAHs in these 2 data sets are compared in Table 3. There are data
on 9-16 cPAHs from 8 of the comparison stormwater settling pond samples. The mean B[a]P
fractions of the total B[a]P PEQMDH from these data are 0.075 to 0.156 depending on the
treatment of no detects for cPAHs found in at least 1 sample (see Attachment 2). These data
suggest 7.5 – 16 % of the B[a]P PEQMDH is attributable to B[a]P. If this fingerprint is used to
characterize the sediment mixture, the cancer potency of individual samples is estimated to be
between 6.4 and 13.3 (or 1/0.16 and 1/0.075) times the B[a]P concentration in the sample. These
data suggest that Varney Pond cPAHs are 6.4 to 13.3 times more potent than the B[a]P content
of sediment samples suggests.
Upon inspection of the MPCA settling ponds sediment data (Attachment 3), MDH believes that
these comparison data are not good quality analytical data because of the variance in cPAH
signature between individual samples, possibly due to variable detection limits. However, these
data do not contradict and may support the whole mixture potency estimate of 10 times the B[a]P
potency as the cPAH potency of Varney Pond sediment samples.
3. Uncertainties and data gaps; and information that could decrease uncertainty
and increase confidence in risk estimates
B[a]P Cancer Slope Factor
Changes to the B[a]P CSF will affect the overall cancer potency evaluation of environmental
PAH mixtures. MDH is planning to evaluate the B[a]P oral CSF as part of our regular
evaluation of chemicals for MDH Health Risk Limits. In the meantime the data from the NTP
mouse study are preferred and will be included in any B[a]P evaluation conducted by MDH.
Adjustment of lifetime B[a]P CSF for early-life sensitivity during less-than-life exposures
Increased early-life sensitivity to carcinogens has not been considered in evaluations of Varney
Pond PAH data. MDH recommends applying a default early-life sensitivity adjustment to
11
carcinogens for which there are not specific early-life sensitivity data available. The
recommended default early-life sensitivity adjustments are 10 times and 3 times the adult
sensitivity for children to 2 years and 16 years of life, respectively. The OEHHA PHG CSF
(CSF70yr; 2.9 (mg/kg/d)-1) includes an early-life sensitivity adjustment that is calculated for
application to the lifetime (70 year) drinking water exposure estimate. MPCA SRVs assume
exposure to carcinogens in the soil occurs for 33 years. If exposure is limited to the first 33 years
of life, the CSF adjustment will be greater than if it is applied to 70 years. Application of earlylife sensitivity CSF adjustment over the first 33 years of life suggests a 2.1 to 2.4 times increase
to the adult CSF (depending on anticipated exposure during an infant’s first year). This results in
a CSF33yr of 3.6 – 4.1 (mg/kg/d)-1.
MPCA SRVs generally consider a childhood ingestion rate of 100 milligrams (mg) daily of soil
for a 15 kilogram (kg) child, and 50 mg daily for a 70 kg adult. Improved less-than-life CSF
estimates would also require matching soil exposure and carcinogen sensitivity age groups. Use
of the CSF33yr or the OEHHA PHG CSF70yr would be appropriate until a full analysis of early-life
sensitivity and exposure is undertaken.
What happens when or if the US EPA draft Relative Potency Guidance is approved?
Approval of the proposed draft RPF Guidance (US EPA, 2010) by the US EPA will not impact a
whole mixture evaluation of cPAHs in dredged sediments, but will establish potency equivalents
for use in environmental PAH contamination evaluations, and standardize RPFEPA for nonheterocyclic, non-alkylated PAHs. Other classes of PAHs (heterocylic and/or alkylated) will
remain underevaluated, but many potent cPAHs will likely be recommended for analysis by US
EPA. It is possible that cPAH potency calculated using the RPFEPA will be either greater or less
than those calculated using PEFMDH. If (draft) RPFEPA were used to evaluate the 8 MPCA
settling pond sediment samples with extended cPAH data (Attachment 3), the RPFEPA evaluation
suggests a 1.9 (standard deviation 1.1) times greater potency than the PEFMDH evaluation. The
correlation of sample potencies between the PEFMDH and RPFEPA evaluations is quite good
(0.96). Note that a number of potent cPAHs for which there are RPFEPA (e.g. benzo(c)fluorene)
were not analyzed in MPCA’s 8 samples.
Validation of relative potency or potency equivalence approach for evaluating PAH cancer
potency
Attempting to validate the use of potency additivity in mixtures, numerous studies have
investigated the cancer potency of binary and multiple PAH mixtures (reviewed in US EPA,
2010). Mixture cancer potencies seen in these studies have been additive, synergistic or
antagonistic – likely dependent on the induction or inhibition of activating enzymes and on
interaction of carcinogenic mechanisms. Similarly, cancer potency of complex environmental
mixtures may appear greater than, equivalent to or even less than the additive potencies of
specific cPAHs in the mixtures (US EPA, 2010, pg 52-54). This is likely due to exclusion of
some potent cPAHs from consideration, interactions between different PAHs, or between PAHs
and other constituents of the mixture (e.g. carbon, the sediment matrix).
Potency evaluations of mixtures have additional complexity because different cPAHs, applied in
the same manner, may cause different types of cancer. Ingested B[a]P appears to be a potent
gastro-intestinal carcinogen, but it has not been shown to induce lung cancer. On the other hand,
dibenzo[a,l]pyrene (IARC, 2010) and benzo[c]fluorene (Koganti et al., 2000) appear to be potent
lung carcinogens when ingested. Neither of these carcinogens were included in early cPAH PEQ
12
evaluations. However, MDH guidance (and California B[a]P PEQ guidance on which it was
based) includes a dibenzo[a,l]pyrene relative potency, and US EPA’s Draft Proposed Guidance
includes relative potencies for both dibenzo[a,l]pyrene and benzo[c]fluorene.
US EPA Draft Relative Potency Factor guidance (2010; pg 42-52) contains a review of the
history of various RPF approaches to cPAH evaluation. Additivity is the general assumption in
current potency equivalent evaluations of cPAH carcinogenicity, and at this time it appears to be
the best method for estimating mixture potency from constituent cPAH data.
Would additional data from Varney Pond result in a better potency evaluation?
Estimates from surrogate whole mixture (coal tar) potency data and MPCA surrogate stormwater
settling pond sediment data suggest a reasonable potency estimate of 10 times the potency of
B[a]P concentration for Varney Pond and other settling pond sediments that will be land applied.
High quality analyses of more cPAHs in Varney Pond sediment samples could result in higher
potency estimates. It is not clear whether additional data for B[a]P PEQMDH analyses would
result in an evaluation that would be more acceptable than the whole mixture analysis discussed
in this document. A whole mixture potency evaluation will generally provide a better potency
characterization than a sum of potency equivalents.
Generally, it would be useful to have a good fingerprint of stormwater settling pond PAHs so
that there is a good database of potent constituent cPAHs in this environmental mixture. Once a
good fingerprint is established for a source or source-type, the number of PAH analytes for
environmental samples from the same source can be minimized.
IV. Conclusions

Disposal of Varney Pond sediments in a properly constructed and maintained berm or hill
near the Pond should not result in additional significant PAH exposures to nearby
residents if:
o all sediments with greater than 1/10th of the MPCA B[a]P SRV are covered
according to guidance developed by the MPCA;
o buried sediments are assumed to have a potency equivalent to 10 times the B[a]P
concentration in the sediment.

Updating the MPCA SRV with a more current cancer slope factor that incorporates early
life sensitivity to carcinogens and by matching early life sensitivity with early life
exposure estimates will make the B[a]P SRV more defensible – but is unlikely to lead to
a large change from the current SRV.

MDH has not evaluated exposures to in-place sediments in Varney Pond. However,
MDH has looked at recreational exposure to sediments at other locations and found that
direct exposures to PAHs in sediments may result in skin irritation; and longterm
exposures could result in additional health impacts. Residents with access to Varney
Pond and others, possibly including students from the adjacent White Bear Lake High
School, appear to use Varney for recreation. If they are wading or swimming in the
Pond, they may be exposed to contaminants above levels of concern. No data are
available on possible fish contamination.
13
o Varney Pond is a stormwater settling pond, intended to collect sediments and
contamination from stormwater runoff. It was not designed to be a recreational
lake.
o There may be chemicals in addition to those tested that may be of interest if
exposure is to in-place contaminants.

Assuming the lack of site-specific experimental or epidemiological cPAH potency data,
there are 2 methods for estimating the carcinogenic potency of an environmental PAH
mixture: a whole mixture potency method which assumes that the known potency of a
surrogate mixture is similar to the potency of the environmental mixture of interest; or
adding the potencies of individual cPAHs found in the environmental mixture of interest.
Currently, the best estimate of the potency of Varney Pond sediment was developed using
the whole mixture potency approach, assuming that coal tar is a reasonable surrogate
PAH mixture.

A cPAH potency estimate for Varney Pond sediments that is likely to be protective of
public health is 10 times the potency of the B[a]P in individual samples.

It is unlikely that additional cPAH fingerprint data from Varney Pond would lead to a
better potency estimate. However, additional stormwater sediment cPAH data could be
helpful for establishing a signature for urban stormwater pond sediments that can be
compared with other environmental PAH signatures.

Acceptable B[a]P cancer slope factors (CSFs) for evaluating Varney Pond, site-specific
ingestion and dermal exposure range between the US EPA IRIS CSF (7.3 (mg/kg/d)-1)
and the California age-adjusted CSF used in the drinking water Public Health Goal (2.9
(mg/kg/d)-1).

The California B[a]P PHG CSF early-life adjustment of 1.7 was specific for drinking
water intake over a 70 year lifetime. Another appropriate CSF adjustment based on a 33
year (soil) exposure may be 2.1-2.4. In addition, MPCA SRVs currently do not match
early-life sensitivity to carcinogens with exposure criteria for similarly aged individuals.

Analytical data for a few potent cPAHs are likely to drive B[a]P PEQ potency estimates.
For evaluating the cancer risk from environmental PAH mixtures (including stormwater
settling pond sediments) using a potency equivalence method, targeted cPAH analytes in
the future are likely to include the following 17 cPAHs from MDH cPAH and EPA Draft
cPAH lists:
benzo[a]pyrene
dibenzo[a,e]pyrene
1,6-dinitropyrene
benzo[b]fluoranthene
dibenzo[a,h]pyrene
1,8-dinitropyrene
benzo[c]fluorene
dibenzo[a,i]pyrene
3-methylcholanthrene
cyclopenta[c,d]pyrene
dibenzo[a,l]pyrene
5-methylchrysene
dibenz[a,h]anthracene
7H-dibenzo[c,g]carbazole
6-nitrochrysene
dibenzo[a,e]fluoranthene
7,12-dimethylbenz[a]anthracene
Additional cPAHs either have low potency, unresolved analytical encumbrances, or have
limited potency testing data. However, including additional PAH analytes (such as
standard non-carcinogenic PAHs and alkylated PAHs) may be important for developing a
PAH signature (fingerprint) of contamination (for environmental forensics or for source
14
apportionment), for establishing ecological risk, for developing non-cancer potency
estimates or for regulatory compliance.

Populating and maintaining a database of cPAHs from different sites and source-type
should simplify cPAH screening of sites with similar cPAH sources in the future.

If US EPA Draft RPF Guidance becomes recommended policy, potency estimates for
some individual cPAHs and for PAH mixtures may change.
V. Recommendations

Varney Pond sediments that are kept on-site and contain B[a]P at concentrations greater
than 1/10th of the MPCA SRV should be covered. Buried sediments should be assumed
to have a potency equivalent to 10 times the B[a]P concentration in the sediment.

Use of a site-specific B[a]P CSF of 2.9 - 4.1 (mg/kg/d)-1 (which include age dependent
sensitivity adjustments) is preferred by MDH until our B[a]P review is complete.

Residents with access to Varney Pond should be informed of the potential hazards
associated with exposure to in-place contaminants in the Pond, and discouraged from
exposing themselves to pond sediments. Data on contamination in fish are not available,
so MDH does not have specific fish consumption advice for Varney Pond.
VI. Public Health Action Plan

MDH will review environmental data and stormwater sediment remediation guidance as
requested by the MPCA.

MDH will continue developing newer guidance on B[a]P.

MDH will be reviewing cPAH guidance in the future to assure consistency with US EPA
guidance.
15
VII. References
Boerngen, J.G. and H.T. Shacklette (1981). Chemical analysis of soils and other surficial
materials of the conterminous United States. U.S. Geological Survey Open-File Report
81-197: 143.
Braun Intertec Corporation (2008). Pond Evaluations: Heiner's Pond, Oak Knoll Pond, Pepper
Tree Pond and Varney Pond. Prepared for City of White Bear Lake. May 20, 2008.
California Office of Environmental Health Hazard Assessment (2010). Public Health Goals For
Chemicals In Drinking Water: (Draft) Benzo[a]pyrene. July 2010.
California Office of Environmental Health Hazard Assessment (2009). Appendix B. Chemicalspecific summaries of the information used to derive unit risk and cancer potency values.,
Air Toxics Hot Spots Risk Assessment Guidelines Part II: Technical Support Document
for Cancer Potency Factors. May 2009.
Crane, J. (2011). email to Thompson, D. and D. Berger, EAO Technical Assistance to
Stormwater Program on Varney Pond Pilot Project. Minnesota Pollution Control Agency,
St. Paul. January 10, 2011.
Culp, S., D. Gaylor, W. Sheldon, L. Goldstein and F. Beland (1998). A comparison of the tumors
induced by coal tar and benzo [a] pyrene in a 2-year bioassay. Carcinogenesis 19(1): 117.
Gaylor, D., S. Culp, L. Goldstein and F. Beland (2000). Cancer Risk Estimation for Mixtures of
Coal Tars. Risk Analysis 20(1): 81-86.
International Agency For Research On Cancer (2010). Some Non-heterocyclic Polycyclic
Aromatic Hydrocarbons and Some Related Exposures. In: IARC Monographs on the
Evaluation of the Carcinogenic Risks to Humans. Lyon, France, World Health
Organization,. V. 92.
Koganti, A., R. Singh, K. Rozett, N. Modi, L. Goldstein, T. Roy, F. Zhang, R. Harvey and E.
Weyand (2000). 7H-benzo [c] fluorene: a major DNA adduct-forming component of coal
tar. Carcinogenesis 21(8): 1601.
Minnesota Department of Health (2006). Technical review of discrepancies in 2002 Laser
Induced Fluorescence data, and 2003 and 2004 analytical data, St. Paul, MN. Health
Consultation Site Assessment and Consultation Unit, Environmental Health Division.
June 30, 2006.
Minnesota Department of Health (2001). Health Risk Values: Statement of Need and
Reasonableness. St. Paul, MN. August 10, 2001.
http://www.health.state.mn.us/divs/eh/risk/rules/air/hrvsonar.pdf
Minnesota Pollution Control Agency (2011). Remediation Division Policy on Analysis of
Carcinogenic Polynuclear Aromatic Hydrocarbons (cPAH). Information Sheet. St. Paul.
August 8, 2011. http://www.pca.state.mn.us/index.php/view-document.html?gid=16052
Minnesota Pollution Control Agency (2002). Carcinogenic Polynuclear Aromatic Hydrocarbons
(cPAHs). Gary Pulford, MPCA, St. Paul. Memo To VIC and Superfund Staff. October
29, 2002.
Schneider, K., M. Roller, F. Kalberlah and U. Schuhmacher-Wolz (2002). Cancer risk
assessment for oral exposure to PAH mixtures. Journal of Applied Toxicology 22(1): 7383. http://dx.doi.org/10.1002/jat.828
U.S. Environmental Protection Agency (2010). [DRAFT] Development Of A Relative Potency
Factor (Rpf) Approach For Polycyclic Aromatic Hydrocarbon (Pah) Mixtures. Office of
16
Research and Development, National Center for Environmental Assessment. EPA/635/R08/012A, February, 2010.
U.S. Environmental Protection Agency (2002). Peer Consultation Workshop on Approaches to
Polycyclic Aromatic Hydrocarbon (PAH) Health Assessment. U.S. Environmental
Protection Agency, National Center for Environmental Assessment, Office of Research
and Development,, Washington, DC. EPA/635/R-02/005, January 2002.
Van Metre, P. and B. Mahler (2010). Contribution of PAHs from coal-tar pavement sealcoat and
other sources to 40 US lakes. Science of The Total Environment.
Wang, Z., M. Fingas and D.S. Page (1999). Oil spill identification. Journal of Chromatography A
843(1-2): 369-411.
http://www.sciencedirect.com/science/article/pii/S002196739900120X
17
Attachment 1
Braun Laboratory Spreadsheet (BL-08-00749 0801278.xls - Varney Data (raw)) - - (unedited - received by MDH 2/4/2011)
CAS No.
Compound/Parameter
Semivolatile Organic Compounds(mg/kg dry)
2-Methylnaphthalene
Acenaphthene
Acenaphthylene
Anthracene
Benz(a)anthracene
Benzo(a)pyrene
Benzo(b)fluoranthene
Benzo(g,h,i)perylene
Benzo(k)fluoranthene
Carbazole
Chrysene
Dibenz(a,h)anthracene
Dibenzofuran
Fluoranthene
Fluorene
Indeno(1,2,3-cd)pyrene
Naphthalene
Phenanthrene
Pyrene
BaP Equivalent**
Metals(mg/kg dry)
Arsenic, Total
Copper, Total
Other Parameters
% Solids(% Wt )
Sample Identifier Sample Identifier Sample Identifier Sample Identifier Sample Identifier Sample Identifier Sample Identifier Residential Industrial Tier I Soil
Soil
Soil
Leaching
Varney 1 0-2'
Varney 1 2-4'
Varney 2 0-2'
Varney 3 0-2'
Varney 3 2-4
Varney 4 0-2'
Varney 4 2-4'
Reference Reference
Value
91-57-6
83-32-9
208-96-8
120-12-7
56-55-3
50-32-8
205-99-2
191-24-2
207-08-9
86-74-8
218-01-9
53-70-3
132-64-9
206-44-0
86-73-7
193-39-5
91-20-3
85-01-8
129-00-0
<0.12
0.34
<0.12
1.5
3.6
3.8
3.3
2.4
4.4
1.1
4.2
0.96
0.23
12
0.55
2.1
<0.12
7.8
10
<0.12
<0.12
<0.12
0.20
0.41
0.35
0.37
0.19
0.38
<0.12
0.47
<0.12
<0.12
1.2
<0.12
0.18
<0.12
0.89
0.96
<0.11
0.11
< 0.11
0.49
1.1
1.1
1.1
0.79
1.1
0.27
1.2
0.23
<0.11
3.0
0.17
0.66
<0.11
2.0
3.1
<0.32
0.42
< 0.32
1.2
4.2
5.4
7.6
0.80
5.7
0.90
5.8
<0.32
<0.32
14
0.63
0.90
< 0.32
9.0
12
7.48
<0.20
0.23
<0.20
0.67
2.4
2.7
3.0
0.51
2.7
0.51
2.9
0.21
< 0.20
9.5
0.37
0.58
<0.20
5.2
5.7
3.71
<0.19
0.39
<0.19
1.2
4.2
4.9
6.8
0.62
5.9
0.96
5.8
<0.19
0.22
13
0.52
0.78
<0.19
9.2
9.4
6.83
<0.22
0.22
<0.22
0.76
2.9
3.5
4.7
0.62
4.2
0.67
4.1
<0.22
<0.22
9.6
0.31
0.71
<0.22
5.9
7.8
4.92
100
1200
NE
7880
***
***
***
NE
***
700
***
***
104
1080
850
***
10
NE
890
2
369
5260
NE
45400
***
***
***
NE
***
1310
***
***
810
6800
4120
***
28
NE
5800
3
NE
50
NE
942
***
***
***
NE
***
NE
***
***
NE
295
47
***
7.5
NE
272
10.2
7440-38-2
7440-50-8
<1.1
19
1.5
11
0.98
28
1.9
22
1.6
12
1.2
15
<1.3
15
5
11
20
9000
15.1
400
NA
83
83
91
50
82
82
74
Notes:
[2]
The spike recovery is outside of laboratory control limits for the matrix spike (MS) and/or the matrix spike duplicate (MSD).
[3]
The method reporting limits (MRLs) are elevated due to adjustments of the sample preparation amounts. This was necessary because of the sample matrix. (all SVOCs analyzed)
[4]
The method reporting limit (MRL) was raised for one or more analytes; a dilution of the sample was necessary due to high analyte levels and/or matrix interferences.
mg/kg = Milligrams per kilogram.
< = Less than the reporting limit indicated in parentheses.
NE =Not Established
SRV - Soil Reference Value established by the Minnesota Pollution Control Agency; 1999, revised 2005
SLV - Soil Leaching Value established by the Minnesota Pollution Control Agency; 1999, revised 2005
** = Benzo(a)pyrene (BaP) equivalent is calculated based on the concentration and weighted toxicity of carcinogenic PAHs (cPAH); Minnesota Pollution Control Agency, 2002.
*** = cPAH. Individual SRV or SLV not established. Included in BaP equivalent calculation.
Attachment 2(a)
0.9
9
0.8
8
0.7
7
0.6
6
0.5
5
0.4
4
0.3
3
0.2
2
0.1
1
0
0
[ ] Aqua columns historically analyzed cPAHs
[ ] Maroon columns cPAHMDH
Sum of B[a]P PEQ fractions = 1
Total of 8 samples were considered in analysis (non shaded data from Attachment 3)
Number of sample detections for each analyte on right vertical axis and in dotted, clear
columns.
Detected in n samples
PEQ fraction
cPAH Potency Equivalence (B[a]P-PEQ) Signature:
Non-detects = 0 in calculations of analyte PEQ fraction means
MPCA Stormwater Pond Sediment Data (from Attachment 3)
Attachment 2(b)
0.9
9
0.8
8
0.7
7
0.6
6
0.5
5
0.4
4
0.3
3
0.2
2
0.1
1
0
0
[ ] Aqua columns historically analyzed cPAHs
[ ] Maroon columns cPAHMDH
Total of 8 samples were considered in analysis (non shaded data from Attachment 3)
Number of sample detections for each analyte on right vertical axis and in dotted, clear
columns.
Sum of B[a]P PEQ fractions = 2.08
Error bars show standard deviation of signature fraction (between samples) for detections
only
Detected in n samples
PEQ fraction
cPAH Potency Equivalence (B[a]P-PEQ) Signature:
Non-detects ignored in calculations of analyte PEQ fraction means
MPCA Stormwater Pond Sediment Data (from Attachment 3)
Attachment 3
M-1
RLE-2
RLP-2
HA-1-01
HA-1-02
HA-1-03
HA-2-04
HA-2-05
HA-2-06
HA-3-07
HA-3-08
HA-3-09
3.49
8.52
3.07
0.029
0.019
0.06
0.002
2.3
0.32
8.5
0.22
0.043
0.053
0.032
0.071
0.003
2.7
3.9
8.7
0.31
0.057
7.22
19.5
7.09
0.085
0.056
0.12
0.005
4.9
7
16
0.56
0.11
1.81 0.495
4.45
4.67
1.28
10.3
1.74 0.417
4.43
0.005 0.042 0.005
0.005 0.027
0.01 0.074
0.002
0.76
2.8 0.065
0.48
3.9
0.06
1.9
8.9
0.13
0.043
0.28
0.009 0.061
Benzo-a-anthracene
Benzo(j & k)fluoranthene
Benzo(g,h,i)perylene
Benzo(e)pyrene
Benzo(b,j,k)fluoranthene
0.422
0.378
10.4
1.77
1.06 0.391
0.65
25.4 0.828
4.02
0.596 0.284 0.336
9.1
1.83
0.007
0.017 0.002 0.087 0.003 0.022
0.005
0.012 0.001
0.06 0.002 0.015
0.01
0.007 0.005
0.15 0.008 0.031
0.005
0.002
0.48 0.024 0.036
0.02 0.013
1.3 0.097
8.5
0.23
1.4
0.64 0.019 0.024
0.071
0.14
10
0.37
2.1
1.6
0.075 0.054 0.031
3.5
0.81
25
1.8
4.4
0.03
0.026 0.022
0.61 0.034
0.09
0.009
0.14 0.015 0.016
0.518
0.881
0.396
0.007
Shaded data not used in cPAH analyses due to small number of cPAH and cPAHMDH analytes or detects
0.006
0.025
0.086
0.16
0.019
0.013
Pyrene
Phenanthrene
Naphthalene
Indeno-1,2,3,-c,d-pyrene
Fluorene
Fluoranthene
Dibenzo-a-l-pyrene
Dibenzo-a-i-pyrene
Dibenzofuran
Anthracene
Acenaphthylene
Benzo(b & j)fluoranthene
2.97
1.74
2.97
7.27
4.01
8.08
3
1.94
2.43
0.031 0.035 0.032
0.02
0.021 0.023 0.023 0.013
0.055 0.032 0.051 0.038
0.002
1.8
1.6
2.2
2.2
2.7
2.3
3.1
2.4
5.7
5.3
7
7.7
0.21 0.096
0.25
0.15
0.039 0.015 0.049 0.035
0.038
0.65
0.079
0.61
0.096
3.1
0.019 0.029
0.007
0.01
Dibenzo-a-h-pyrene
Dibenz-a-h-anthracene
Dibenz-a-h-acridine
Chrysene
0.15
0.083
Carbazole
Benzo-k-fluoranthene
0.007
0.15
0.17
1.3
0.021
0.008
Dibenzo-a-e-pyrene
0.022
0.032 0.017
0.045
Dibenz-a-j-acridine
0.071
0.097
Benzo-j-flouranthene
Benzo-b-j-k-fluoranthene (total)
0.19 0.047
0.34 0.041
0.5
0.14
0.04
0.06
Acenaphthene
7H-Dibenzo_c-g_carbazole
7-12 Dimethylbenzanthracene
6-Nitrochrysene
5-Nitroacenaphthene
5-Methylchrysene
4-Nitropyrene
3-Methylcholanthrene
2-Nitrofluorene
1,8-Dinitropyrene
1-Nitropyrene
0.073
0.12
5.41
14.8
5.35
0.559
0.027
0.019
0.026
Benzo-b-fluoranthene
3/5/2009
3/5/2009
3/5/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
0.546
1.94
0.397
0.002
0.004
0.002
0.003
0.003 0.002 0.008
0.708
0.456
Benzo-a-pyrene
M-1
RLE-2
RLP-2
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
1,6-Dinitropyrene
Total Of Result ppm
56.81
145.2
52.33
0.606
0.409
1.019
0.027
45.12
53.12
149.4
3.956
0.892
SampleID
ncPAH-MDH(not old EPA)=
2
4
4
4
3
3
0
10
10
8
5
1
Sampling Date
Round Lake Ponds
Round Lake Ponds
Round Lake Ponds
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
8
10
10
10
8
9
4
16
16
14
11
6
StationID
M-1
RLE-2
RLP-2
HA-1-01
HA-1-02
HA-1-03
HA-2-04
HA-2-05
HA-2-06
HA-3-07
HA-3-08
HA-3-09
ncPAH =
3/5/2009
3/5/2009
3/5/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
4/24/2009
SampleID
Sampling Date
M-1
RLE-2
RLP-2
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
ProjectName
Round Lake Ponds
Round Lake Ponds
Round Lake Ponds
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
Rupp Pond
StationID
ProjectName
PAHs in Stormwater Pond Sediments (MPCA)
4.78
7.44
10.4
19.9
3.18
6.29
0.03 0.062
0.027 0.044
0.068
0.11
0.003 0.004
4.3
6.2
4.5
7.5
17
20
0.23
0.45
0.072
0.1
Preparers of the Report:
Carl Herbrandson, PhD
Toxicologist, Minnesota Department of Health
CERTIFICATION
This Varney Pond: Stormwater Settling Pond Sediments Health Consultation was prepared by
the Minnesota Department of Health (MDH) with support from the Agency for Toxic Substances
and Disease Registry (ATSDR). It is in accordance with approved methodology and procedures
existing at the time the health consultation was begun. This document has not been reviewed
and cleared by ATSDR. Editorial review was completed by additional programs of MDH.
____________________________________
Rita B. Messing, PhD, Supervisor
Site Assessment and Consultation Unit, Environmental Assessment and Surveillance Section,
Division of Environmental Health, Minnesota Department of Health
18