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Site Background
The Anaconda Smelter site in Deer Lodge County, Montana, encompasses over 100 square miles that have been affected by 100 years (1880s to 1980s) of milling and smelting operations. Aerial stack emissions and stream discharges, as well as wind dispersal, have transported metal-contaminated wastes, over a wide area. These wastes include approximately 230 million cubic yards of concentrated mine tailings, 30 million cubic yards of furnace slags, 500,000 cubic yards of flue dust, and many square miles of contaminated soils (CDM 1997). The site was placed on the National Priorities List (NPL) and under the authority of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) in 1983.
The contaminants of concern (COCs) at the site are a variety of forms and concentrations of arsenic, cadmium, copper, lead and zinc.
Ecological effects at the Anaconda site are predominated by extensive phytotoxicity which has left vast areas (approximately 18 square miles) either denuded of vegetation or severely stressed in their vegetative components. Risks to vegetation were documented in the US Environmental Protection Agency's (EPA's) Baseline Environmental Risk Assessment (BERA) for the Anaconda Smelter Site (Site).
Significant remedial action has been planned in response to hazards posed to vegetation by metal and metalloid contamination. The BERA for the Site also identified several wildlife receptors having the potential for deleterious exposures to the same contaminants. Excess risk to wildlife has been suggested based on modeling exercises evaluating contaminant uptake from
foraging, food chain movement, drinking water and direct ingestion of contaminated soils. Modeled species, selected as representatives of feeding and habitat guilds, were white-tailed deer (Odocoileus virginianus), deer mouse (Peromyscus maniculatus), American robin (Turdus migratorius), red fox (Vulpes vulpes) and American kestrel (Falco sparverius). Direct assessment of wildlife has been limited. Investigations conducted on the Anaconda Smelter Site have not included studies of actual health effects endpoints in wildlife inhabiting areas impacted. Currently, risk management decisions have been focused on soil amendments to reduce the exposure of metals and metalloids to vegetation and it is anticipated that these techniques would also indirectly reduce exposure to wildlife receptors. No remedial action, however, has been planned to directly reduce potential metal exposure to wildlife.
It is, therefore, important to collect pertinent biological data, both to validate risk models used in the BERA to predict the geographical extent of current wildlife risk, and to determine the most pertinent and cost effective long term data collections to ensure protection of wildlife species.
Current Study
The study under way at Anaconda strives to investigate wildlife health effects on the Anaconda Smelter Site. Through this assessment, pertinent issues of exposure and effects can be identified for consideration for more long-term analyses.
The overall goal of this study is to provide wildlife health effects information to:
1) more accurately understand the geographic extent of wildlife risk by validating existing models used in the Site BERA for predicting site-associated hazards to wildlife, and
2) aid in the development of a wildlife biomonitoring plan to evaluate the extent of residual risk after remedy completion. The biomonitoring data will be used for the Site's 5-year review.
The current investigation assesses the survival, reproduction and general health of American kestrels, European starlings and several passerine species as well as small mammal populations, in areas on and adjacent to the Anaconda Smelter Site. As studies are ongoing, we will update this site periodically as new data become available.
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