Validation of Corbicula fluminea Growth Reductions Induced by Copper in Artificial Streams and River Systems

Abstract

Studies designed to evaluate impacts of copper (Cu) on Asiatic clams, Corbicula fluminea, in artificial stream and field environments were conducted. Adult and juvenile responses (survival and growth) to Cu, relevance to Cu bioaccumulation, site-specific comparisons, and the relation to observed densities of resident clams at an impacted site were assessed. Juveniles were more sensitive than adults; however, clam tissue and shell growth were significantly impaired (p < 0.001) for both juveniles and adults at 8.4–26.7 μg Cu/L in artificial streams. Tissue levels of Cu were 2.5–6 times greater at 8.4–26.7 μg/L exposure concentrations compared with background body burdens in unexposed clams. In studies conducted at the Clinch River, Virginia power plant, clam growth was reduced at 22.5–104.8 μg/L at a water hardness (180 mg/L) that was more than two times the hardness in artificial streams. Clam population densities in the river were well correlated with outcomes of field growth studies. Corbicula fluminea growth patterns are a clear and interpretable indicator of Cu contamination in natural and artificial streams and represent a viable alternative to contemporary chronic testing protocols.