Funding Program: Contaminant Biology
Statement of Problem: The upper Tennessee and Cumberland River basins support one of the most diverse assemblages of freshwater mussels in the world. Sixty freshwater mussel species occur in these basins and 30 are federally protected; no other faunal group in the United States approaches this level of imperilment. Coal mining may be a major factor in the contribution of toxic constituents to the upper Tennessee and Cumberland River basins, increasing the likelihood that several endangered mussel species may become extirpated. More than 66,000 documented sources of coal mining-related discharges and abandoned mine drainages are reported for Appalachia (Cohen and Gorman 1991). These discharges and runoff, which contain metals, hydrocarbons, surfactants and other pollutants, enter more than 17,000 miles of streams and rivers in these basins. Toxic substances were cited as one of the top stressors limiting freshwater mussel recruitment (Richter et al. 1997) Knowledge of the toxicity and sub-lethal effects of coal mining-related effluents to freshwater mussels is extremely limited. Some contaminants (e.g., copper, ammonia) have been demonstrated to be highly toxic to mussels at concentrations below the USEPA aquatic life criteria. Limited data from a study of coal preparation plant effluents showed some toxicity to early life stages of two mussel species (FWS 2004). Microscopic evaluations of histologically-prepared tissues have provided documentation of adverse, sub-lethal cellular effects in mollusks resulting from exposure to metals and organic contaminants (Byrne and O’Halloran 2001; Moore and Allen 2002; Lajtner et al. 2003; Aarab et al. 2004; Kim and Powell 2004; Werner et al. 2004; Spoljar et al. 2005; Tanhan et al. 2005; Ortiz-Zarragoitia and Cajaraville 2006). This study will augment previous work performed by USGS on sediment toxicity in the basins and the information will be of direct significance to the Fish and Wildlife Service, National Park Service, and Office of Surface Mining, and state regulatory agencies. By assessing multiple effects endpoints with mussels, this study will provide a scientifically sound basis upon which the Service can make informed decisions for mussel recovery efforts in the upper Tennessee and Cumberland River basins and provide recommendations to state regulatory agencies. Results of this research will enhance the recovery of 30 federally listed aquatic mollusks.
1. Assess acute and chronic toxicity of treated mine waters, coal preparation plant effluents, and slurries to standard bioassay organisms and juvenile freshwater mussels.
2. Characterize the constituents of the waters, effluents, and slurries used for toxicity testing under Objective 1.
3. Assess surviving juvenile mussels for sub-lethal effects, observed as histological anomalies following exposure during the toxicity testing conducted under Objective 1.