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Allied Paper Ecological Risk Assessment
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Site Background
Due to the PCB contamination, in August 1990 the site was placed on the Superfund or National Priorities List (NPL). The NPL Study Area (API/KR/PC) includes 3 miles of Portage Creek, from Cork Street to its confluence with the Kalamazoo River, and 80 miles of the Kalamazoo River, from Morrow Lake Dam downstream to Lake Michigan. Also included in the site are five paper residual disposal areas and five paper mill properties.
The Michigan Department of Community Health has issued a species-specific no consumption fish advisory annually since 1977 for the Kalamazoo River portion of this site due to PCB contamination. The Kalamazoo River and Portage Creek have been designated a site of environmental contamination under Part 201, Environmental Remediation, of the Natural Resources and Environmental Protection Act, 1994 PA 451, as amended (NREPA), due to PCB contamination. The Kalamazoo River and Portage Creek have also been identified as an Area of Concern by the International Joint Commission on the Great Lakes due to the detrimental impact the ongoing release of PCBs has on Lake Michigan.
Null hypotheses:
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The null hypotheses for the API/PC/KR are defined as follows:
- The levels of PCBs in water, sediment, and biota are not sufficient to adversely affect the structure or function of the fish populations in the Kalamazoo River and Portage Creek System
- The levels of PCBs in water, sediment, and biota are not sufficient to adversely affect the survival, growth, and reproduction of aquatic plant and animal receptors utilizing the Kalamazoo River and Portage Creek system
- The levels of PCBs in water, sediment, and biota are not sufficient
to adversely affect the survival, growth, and reproduction of semi-aquatic
and terrestrial
mammalian receptors utilizing the Kalamazoo River and Portage Creek system - The levels of PCBs in water, sediment, and biota are not sufficient to adversely affect the survival, growth, and reproduction of omnivorous and carnivorous avian receptors utilizing the Kalamazoo River and Portage Creek system
Discussion/Conclusions
The ecosystem associated with the Allied Paper, Inc. / Portage Creek / Kalamazoo River portion of the Kalamazoo River has been and is currently being adversely affected by PCBs originating from past industrial activities. This evidence by the distribution of PCBs in biota at all trophic levels within the Allied Paper, Inc. / Portage Creek / Kalamazoo River.
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Multiple lines of evidence are used to reach the above conclusions.
- Most aquatic biota such as invertebrates and fish are unlikely to be adversely affected by direct contact with and ingestion of surface water because of relatively low PCB toxicity to most aquatic biota. Bioaccumulation of PCBs is not considered at this stage.
- PCB contamination of surface water and streambed sediment is likely to adversely affect sensitive piscivorous predators, such as mink, through consumption of PCBcontaminated prey, especially fish.
- Impaired reproduction of mink and ultimately decreases in mink populations are the most likely effects of PCB contamination in aquatic prey. There is qualitative evidence that mink populations are declining or are reduced.
- Other piscivorous predators, such as bald eagles, are at substantial risk based on assumptions about diet (e.g., fish are the predominant prey item consumed) and exposure (e.g., foraging takes place mostly within contaminated aquatic areas). Preliminary data suggest both these assumptions are valid. Field investigations of bald eagles by U.S. Fish and Wildlife suggest there has been a loss of reproductive capacity and decrease in the populations of bald eagles within the site boundaries.
- Terrestrial and semi-aquatic biota may be at risk from PCB-contaminated floodplain sediment and surface soil, depending on life history (e.g., foraging behavior, diet, mobility) and sensitivity to PCBs. Such risk is in general considered to be low to moderate, depending on species.
- Omnivorous birds (represented by the robin) that consume a substantial amount of soil invertebrates (e.g., earthworms) would be at significant risk if foraging takes place in mostly contaminated areas.
- Carnivorous terrestrial mammals (represented by the red fox) may be at some risk if foraging is concentrated in riparian areas with contaminated floodplain sediment and diet consists of prey that (1) reside in PCB-contaminated areas, and (2) have taken up substantial amounts of PCBs.
- Carnivorous birds (represented by great horned owl) may be at significant
risk, depending on diet. Relatively high risks were calculated in association
with high PCB concentrations in eggs, while risk estimates generated
as a result of food web modeling were comparatively low. Uncertainties
with actual diet of great horned owls in the Allied Paper, Inc. / Portage
Creek / Kalamazoo River area and discrepancies between estimated risks
to owls, based on the two different methods mentioned previously, cannot
be resolved with available data. - Omnivorous terrestrial species (represented by mice) are unlikely to be at
significant risk unless they reside in the most contaminated areas. PCB uptake in mice appears to be relatively low. - Semi-aquatic herbivorous mammals (represented by muskrat) may be at risk from PCB contamination because estimated dietary doses exceed recommended threshold values for rats. This conclusion is based on the assumption that laboratory rats and muskrats are equally sensitive to PCBs via ingestion. Muskrats contaminated with PCBs may also cause adverse effects to muskrat predators because some muskrats contain PCBs in excess of recommended dietary limits for PCB-sensitive predators such as mink.
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This ERA presents overwhelming evidence that, despite uncertainties
identified and discussed in the ERA, two and possibly three of the four
proposed null hypotheses can be rejected with little reservation.
- The first null hypothesis is accepted because there is no direct evidence that fish communities are being affected by PCB contamination. The impaired fish community of Lake Allegan is comprised primarily of stunted and often malformed carp. The cause of these findings cannot be determined from the available data. It is noted, however, that PCBs cause a wasting syndrome in several mammalian species. There is insufficient site-specific data to determine if fish communities in the Kalamazoo River are being directly affected by PCB contamination.
- The second null hypothesis is conditionally rejected. This is based on the finding that at some locations the maximum detected surface water PCB concentrations exceed or closely approach the lowest chronic value for freshwater fish or aquatic plants.
- The last two null hypotheses are rejected because risks to mammalian (e.g., mink) and avian predators (e.g., bald eagle), especially those that consume fish, are unacceptable. These conclusions are based primarily on the very high levels of PCB concentrations in fish, other biota, and abiotic media (e.g., floodplain sediments).