Increased deposition of organic matter, polychlorinated biphenyls, and cadmium by zebra mussels (Dreissenapolymorpha) in western Lake Erie

Biodeposition of organic matter, polychlorinated biphenyls (PCBs), and cadmium (Cd) by zebra mussels (Dreissena polymorpha) was investigated at five stations in the western basin of Lake Erie during the summer of 1992. Biodeposition rates at the five stations were determined by using sediment traps and converted to per unit area values to facilitate comparisons with natural sedimentation rates. Biodeposition of suspended material by zebra mussels was up to 8 times greater than sedimentation in the traps. Concentrations of organic matter, PCBs, and Cd were determined for the biodeposits and the sedimented material. There were no significant differences in concentration of organic matter, PCBs, or Cd between the two types of material. Biodeposition rates per unit area of organic matter, PCBs, and Cd were 8-10 times greater than corresponding values for natural sedimentation; therefore, the natural sedimentation processes of these factors appear to be greatly accelerated in the presence of zebra mussels. Results support the possibility that zebra mussels are altering contaminant movement in western Lake Erie, as well as clarifying the water column by removing suspended material.