State of Oregon
Department of Environmental Quality
To:
Memorandum
File, Boise Cascade Minto-Brown Site (ECSI 355) Date: July 1,2010
S5,v\J1
./
From:
Susan Turnblom
Cleanup Program 'Toxicologist
Subject:
Evaluation of Upland Risk Screening and Potential Risks to the Willamette River and
Slough, Boise Cascade Minto-Brown Site
Boise Cascade Corporation had been participating in our Independent Cleanup Program to evaluate
envirolilllental contamination at the Boise Cascade Minto-Brown island site. This site was formerly
used as the treatment facility for the Boise Cascade paper plant which was located on the adjacent
Salem water front. Boise Cascade withdrew from the Independent Cleanup Program in February
2008.
This memo provides DEQ's review of the Supplemental Risk Evaluation, Boise Cascade, Minto
Island report prepared by CH2MHill for Boise Cascade [CH2M Hill, June 4, 2007]. Their report
presented a focused human health risk screening for recreational users and occupational workers and
a focused wildlife risk screening. Their report does not, however, address potential impacts to the
adjacent Willamette River and Willamette Slough for human health or ecological receptors. Its
scope is limited to the upland portion of the island.
Since the CH2M Hill Supplemental Risk Evaluation did not address potential impacts to the river or
slough, this memo also includes DEQ preliminary evaluation of potential human health and
ecological risk from contaminants detected on the island that may have been discharged into the
Willamette River or Willamette Slough. DEQ used published data and studies, since no site-specific
data has been collected.
The overall purpose ofDEQ's review is to assist the DEQ Cleanup Manager in determining the
priority for fmiher action at the site.
Supplemental Risk Evaluation for Uplands
Human Health - The Supplemental Risk Evaulation evaluated a recreational user and future
occupational worker in the human health risk screening. Only exposure to contaminants on the
upland pOliion of the island was considered in the risk screening, and only samples from a very
limited and focused area on the island (that of a proposed recreational walking paths) were included
in Boise's evaluation.
DEQ concurs that the exposure assumptions developed for the site are reasonably conservative and
protective, and that the calculations were completed correctly. However, only PAHs and dioxins
were evaluated, and only samples collected in 2000 and 2007 were included in the calculations. No
metals or VOCs were assessed. The evaluation showed that cancer risks to both the recreational user
and future occupational worker are below 1 X 10. 6, and hazard indices are below one, which meets
cleanup standards.
Since the sample set of data used for calculating these risks is so limited, and may not be
representative of site-wide conditions, additional samples should be collected from other areas on the
island to be included in future risk calculations.
Status for Human Health Exposure - DEQ had determined that the conditional NFA for industrial
use including maintaining caps and restriction of site access to proposed recreational walking path is
protective for the recreational user and hypothetical fhture occupational worker.
Ecological Receptors - In the Supplemental Risk Evaluation, Boise Cascade, Minto Island CH2M
Hill also performed a Wildlife Risk Screening using soil, sediment and surface water samples that
were collected from the upland pOltion of the island.
For surface water (that is, surface water in the 15 million-gallon (MG) pond on the island), none of
the detected concentrations exceeded DEQ screening level values (SLVs) for wildlife.
For soil, all chemical exposure point concentrations (EPCs) were below mammalian and bird
population SLVs. DDT and barium exceeded SLVsfor individual birds.
For sediment (collected from the upland 50 MG pond), the dioxin/furan SLVs for individual birds
and mammalian populations were exceeded.
Status for Ecological Receptors Exposllre - Based on these findings alone, further investigation of
ecological risk should be conducted, starting with a Level I Ecological Scoping Assessment to
identify appropriate ecological receptors and habitats. The Level I Ecological Scoping Assessment
should look at amphibians, crayfish, clams, bass, and sculpin as potential receptors, the largescale
sucker as a pathway to osprey, and possibly carp as a pathway to humans.
Potential Risl<s to Willamette River and Willamette Slough
Historical wastewater discharges from the fonner Boise Cascade paper mill are known to have
occurred directly to the Willamette Slough and also to the wastewater treatment facility on MintoBrown Island. Historical reports indicate leachate from the wastewater treatment facility on the
island discharged through groundwater into the Willamette River and Willamette Slough.
No site-specific data are available (e.g., sediment or fish tissue samples neal' the historical
wastewater and leachate discharge locations) with which to evaluate the potential impacts from the
paper plant to the river and slough. DEQ reviewed available regional data for two purposes. First,
to evaluate whether the regional data indicate the paper plant and treatment facility likely have
impacted the river and slough. And secondly to see if there are sufficient regional data to help
determine the priority for further action at the site under using the DEQ Site Assessent Prioritization
System (SAPS)l and the Western Region risk-based supplemental priority system 2 .
1 Site
Assessment Prioritization System (SAPS) Version #6, December 2003.
DEQ estimated risk to humans eating fish caught recreationally in the Willamette River. Since no
site-specific data was available, risks were calculated using regional fish tissue data published in
Bioll1agnification Factors (Fish to Osprey Eggs ji-OIl1 Willamette River, Oregon, USA) for PCDDs,
PCDFs, PCBs and OC Pesticides published in Environmental Monitoring and Assessment 84: 275315, 2003. This study published fish tissue concentrations for largescale sucker and northern
pikeminnow sampled between Willamette river miles 54 (south of Newberg) and 170 (south of
Junction City). Please see attached graphical presentation of this fish tissue data.
The Boise Cascade Minto Island site is at River Mile 85. Fish were collected and sampled from
River Mile 88 (tlU'ee miles upstream from Minto Island) and 77 (eight miles downstream from Minto
Island). DEQ used the fish tissue data collected from RM 77 for two reasons: first, the location is
downstream from Boise Cascade and would be more likely to include contributions from Boise
Cascade than samples collected upstream and, second, these fish tissue concentrations are higher
(than the upstream RM 88 fish tissue concentrations) and using them provide the most conservative
estimates of risk.
Using total dibenzo-p-dioxin (PCDD) TEQ data from largescale sucker fish (bottom feeders) caught
at RM 77, the risk to a subsistence fisherperson was calculated to be 1.6 x 10'4, and the risk to a
general/recreational fisherperson was 2 x 10'5.
Using total PCDD TEQ data from northern pikemilIDow caught at RM 77, the risk to a subsistence
fisherperson was calculated to be 1 X 10,4, and the risk to a general/recreational fisherperson was 1
X 10,5.
All of these risks were calculated by comparing Acceptable Tissue Levels (ATLs) in Table A-3 of
DEQ's sediment guidance document with the measured tissue levels in the fish collected for the
biomagnification study. A ratio of the tissue levels was calculated and then the ratio was multiplied
by I X 10'6, which is the risk level at which the ATLs are set.
Limitation of Evaluation - None of the fish sampled were collected from water at the site. They
were either from 3 miles upstream or 7 miles downstream. The higher total PCDD TEQ
concentrations for both fish species (largescale sucker and nOithern pikeminnow) are from the
downstream sampling locations. This introduces the uncertainty that risk from eating fish caught at
or near the site could be either higher or lower, depending on contaminant levels in fish living closer
to the site. There is additional unceltainty in these risk levels because humans are not likely to catch
and eat largescale suckers or northern pikeminnow. These fish were sampled for the
biomagnification study because they comprise a significant portion of the osprey diet. Bass, for
example, are a much more likely food source for humans, and because they are a predatory fish, it is
possible that total PCDD TEQ could be even higher than the existing data, and, thus, human health
risk could be higher.
2 Western Region Supplemental Risk-Based Prioritization System, developed by Paul S. (Max) Rosenberg, Cleanup
Manager, dated JanualY 16,2006.
Statns for Human Health and Ecological Receptors Exposure - Dioxins and furans are clearly
present in the environment and entering into the ecosystem and biomagnifying up the food chain. It
is possible that Boise Cascade's Minto-Brown Island operations have contributed to this
environmental contamination. The regional data in the publised rep0l1 are insufficient to show that
contamination is present because of Boise Cascade. Additional sampling in the river and slough
should be conducted to evaluate any potential contribution from the former Boise Cascade paper
plant.
According to the Western Region Prioritization System for evaluating the Willamette River and
Willamette Slough, is considered a medium priority. There is potential for exposure to human health
above 10-6 risk for consumption of fish.
Conclusions and Recommendations
No samples were collected from or near the Willamette River or the Willamette Slough. This is a
data gap that needs to be addressed. Sediment and pore water samples should be collected from near
shore on both sides of the island, since it is documented that there has been regular flooding of the
island while the ponds were in use, and documented descriptions of black liquor visible in aerial
photos of the slough until 1996.
Benthic invertebrates are likely to be impacted by any historical and ongoing releases of ammonia,
which has been detected in upland sludge samples, and should be investigated further to determine
whether it is an ongoing source of contamination the river and slough. Fish such as sculpin should
be caught and sampled because they have a small home range and would be likely to be repositories
of dioxins and furans. Bass are the fish most likely to be caught and eaten by recreational fishing,
and their home range varies between one-quarter mile and one mile. If caught near the site, it could
provide information on contaminant contributions to the river from Boise Cascade's operations.
Bass tend to like riprap and piers, and could be sampled/collected in the Willamette Slough.
As mentioned previously, a Level I Ecological Scoping Assessment should be completed, and, most
likely, a Level II Ecological Screening Risk Assessment as well.
References
Middle Willamette River Fish Consumption Study
Guidance for Assessing Bioaccumulative Chemicals of Concern in Sediment, 2007
Biomagnification Factors (Fish to Osprey Eggs from Willamette River, Oregon, USA) for PCDDs,
PCDFs, PCBs and OC Pesticides, Environmental Monitoring and Assessment 84: 275-315,2003.
Fish Data
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