EFFECTS OF COAL MINING ON FRESHWATER MUSSELS IN THE NEW RIVER BASIN: A TEST USING CORBICULA AS BIOMONITORS

The New River Basin (NRB) of Tennessee is home to a number of rare endemic aquatic communities. One such community of particular importance to the area, experiencing a precipitous population decline due to the fouling and pollution of their freshwater systems, is that of freshwater mussels (Bogan 2006). This study in the NRB involves measuring the mortality rates of live Asian clam (Corbicula fluminea) assemblages. A common property of aquatic systems influenced by anthropogenic activity is increased conductivity (a proxy correlated to the ability of water to pass an electric current because of increased metal and dissolved solids concentrations) which studies show may impair clam health. Our study of five, coal surface mining, impacted streams within the NRB and a control stream of similar geology tests this correlation. Silos containing live Corbicula fluminea were placed in several localities in streams of the NRB that receive mining drainage as mine drainage is commonly associated with elevated conductivity. The growth rates of these specimens were periodically measured, over the course of 120 days, to determine the effect of water resistivity on clam health. We found that growth and mortality rates of the life assemblages are correlated with conductivity and water temperature level. Specifically, growth rate increased with temperature but growth rate decreased with conductivity, after temperature was accounted for. Overall mortality was low so our findings imply that mining is not immediately lethal to these mussels but does have a negative health impact on them.