Elimination rate constants of 36 PCBs in zebra mussels (Dreissena polymorpha) and exposure dynamics in the Lake St Clair Lake Erie corridor

The elimination kinetics of 36 PCB congeners, ranging in log octanol-water partition coefficients (log K-ow) from 5.60 to 7.50, were determined in zebra mussels (Dreissena polymorpha) with shell lengths from 1.0 to 1.5 cm. Elimination rate constants, based on lipid-normalized data, ranged from 0.172 to 0.042 day(-1) and exhibited a significant negative regression with log K-ow. Time to 95% steady state ranged from 17.5 to 71.0 days and was used to determine the period over which mussels integrated exposure concentrations. Bioavailable PCB congener concentrations, calculated with a steady-state model, were determined from mussels collected offshore of Middle Sister Island in western Lake Erie. Chemical concentrations in water, estimated using mussels, were within an order of magnitude of direct Measurements for congeners with log K-ow < 6.6. The rapid elimination kinetics of zebra mussels suggests that these organisms can closely track temporal fluctuations in ambient chemical concentrations, and therefore have the potential to regulate contaminant cycling in aquatic ecosystems.