Justin T. Hanna

Advisor:  Dr. Carrie Johns

SLU Festival of Science 2001 Poster Presentation

Total Copper Concentrations in Dreissena polymorpha at Selected Sites
In Northern New York

Since its accidental introduction into the Laurentian Great Lakes in the 1980s, the zebra mussel, Dreissena polymorpha, spread rapidly throughout eastern North America.  Bivalves are widely used to monitor biologically available contaminants in aquatic ecosystems because they are sedentary, relatively large sized, and bio-accumulate both metals and hydrophobic contaminants proportional to levels in the environment. By assimilating contaminants from water and food, mussels integrate levels of contamination through time. The zebra mussel, specifically, has been used as a bio-monitoring organism in Europe and has been added to the N.O.A.A. Mussel Watch Program in Lake Erie and Lake Ontario.  The Great Lakes system has historically been contaminated with industrial wastewater discharges as well as urban and agricultural runoff.  We sampled zebra mussels from seven sites: five sites along the St. Lawrence Seaway, one site on Lake Ontario, and one comparison site on Keuka Lake in the Finger Lakes region. We hypothesized that copper concentrations in the mussels would be higher at sites along the Seaway. In the lab, mussels underwent depuration, were sorted into five groups based on shell length, and the soft tissues pooled for analysis by size group. After hot acid reflux in nitric acid, samples were made to final volume and analyzed by flame atomic absorption spectroscopy.  One-way analysis of variance showed that mean size of mussels did not vary significantly among sites. However, mean copper concentrations did vary significantly among sites and were highest at the site at the outflow of Lake Ontario. Copper concentrations were significantly correlated to shell length at only two of seven sites. Comparison to concentrations reported in the literature suggest that copper concentrations in mussels at all sites were elevated compared to mussels from relatively uncontaminated systems.  Our results suggest low level contamination by copper is widespread amongst the sites we sampled, even in mussels from Keuka Lake which we had hypothesized would show lower levels due to the lack of industrial inputs to the lake.