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    Author(s): A. Dennis Lemly
    Date: 2001
    Source: Coldwater Fisheries Research Unit, Blacksburg, Virginia
    Publication Series: Scientific Journal (JRNL)
    PDF: Download Publication  (617 KB)


    Beginning in 1996, selenium associated with phosphate mining on Caribou National Forest (CNF) was implicated as the cause of death to horses and sheep grazing on private land adjacent to the national forest. In response to these concerns, the Forest Service began a monitoring study to determine selenium concentrations in and around the mine sites. By 1998, the study revealed that elevated concentrations of selenium were present in water, sediment, and biota at many locations. In late 1998, CNF staff contacted me and asked if I would interpret the selenium levels and evaluate the toxic threat to fish and wildlife resources. I reviewed the monitoring data, traveled to CNF and conducted an on-site inspection of the mining operations, and prepared a risk assessment report (Lemly, 1999a). The report concluded that there were significant threats to major populations of Yellowstone cutthroat trout and other species that have high management priority with the State of Idaho and the U.S. Fish and Wildlife Service (e.g., rainbow trout, elk, migratory waterfowl, whooping crane, etc.). Concurrent with my involvement, the U.S. Geological Survey began studies to assess the location and geological nature of the selenium sources. By late 1999, it was clear that selenium leaching from phosphate mine wastes on CNF was indeed responsible for the livestock poisonings, and had also contaminated a large part of the Blackfoot River Watershed. The level of contamination in some mine-spoils was great enough to be designated hazardous waste, and caused the U.S. Environmental Protection Agency (EPA) and the U.S. Department of Justice (DOJ) to begin taking action under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, also known as Superfund). The USFWS has taken an active role in the Caribou problem because of risks to migratory waterfowl and whooping crane, which invokes their management responsibilities under the Migratory Bird Treaty Act and the Endangered Species Act. Also, the State of Idaho (State) is designating the Blackfoot River and Blackfoot Reservoir as "impaired water bodies", which triggers federal regulatory actions for remediating water pollution under Section 303(d) of the Clean Water Act. Thus, by 2000, what was initially viewed by some to be a local environmental problem for Region 4 of the Forest Service had escalated into a national, interagency issue, and was identified as one of the most important emerging selenium contamination issues in the USA (Lemly, 1999b).

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    Lemly, A. Dennis. 2001. A technical framework for implementing aquatic ecosystem loading limits (TMDLs) to reduce selenium pollution from phosphate mining wastes on Caribou National Forest, Idaho. Coldwater Fisheries Research Unit, Blacksburg, Virginia

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