THE EFFECTS OF LAND USE ON THE BIOACCUMULATION OF HEAVY METALS IN ASIAN CLAMS: AN INDICATION OF STREAM HEALTH

Heavy metal contamination of waterways has increased due to anthropogenic alterations of natural environments through urbanization and other land-use changes. As such, assessing the fate of heavy metals in aquatic environments has become paramount in determining changes in biogeochemical cycling of heavy metals. Recently, freshwater clams such as the invasive Asian Clam (Corbicula fluminea), have been utilized to determine the bioaccumulation of pollutants and as an indicator of stream vitality. Here we attempted to determine the potential impacts of land use change on the health of the east branch of the Brandywine Creek in Southeastern Pennsylvania using heavy metal concentrations of Asian Clams. In July 2014 we sampled 8 sites differing in their land use patterns; 6 were along the Brandywine creek and 2 sites from a tributary. At each site 10 clams were collected, along with water samples and stream flow. Whole clam soft tissues were digested using nitric acid and analyzed using an inductively coupled plasma mass spectrometer (ICP-MS) for concentrations of Ni, Cu, As, Cd, and Pb. Ni and Cu were the most present metals at each site while Cd was present in the lowest concentrations. Clams from the tributary, Beaver Creek, exhibited the least bioaccumulation of metals while the highest concentrations of heavy metals were found at sites located in close proximity to highly developed and urbanized areas. Overall, this study suggests that an increase in urbanization around the Brandywine Creek will increase heavy metal loading in aquatic organisms and their surrounding environment.