Comparison of polycyclic aromatic hydrocarbon and polychlorinated biphenyldynamics in benthic invertebrates of Lake Erie, USA

The distribution patterns of polycyclic aromatic hydrocarbons (PAHs) and po lychlorinated biphenyls (PCBs) were determined in four benthic invertebrate species of western Lake Erie, USA, to assess and compare the processes gov erning the exposure dynamics of these two classes of contaminants. Signific ant differences in the sum of 17 PAH compounds were observed among the four species, with mayflies containing the highest PAH body burden, followed by dreissenid mussels, amphipods, and crayfish. For PCBs, mayflies contained significantly higher concentrations of the sum of 39 PCB congeners than the other organisms, and dreissenids had higher levels than crayfish. No signi ficant differences were found in the Sigma PCB levels between dreissenids a nd amphipods or between amphipods and crayfish. For PCBs, the relationship between biota-sediment accumulation factors (BSAFs) and log K-ow followed a parabolic pattern indicative of selective bioaccumulation. In contrast, BS AFs for PAHs were inversely related to log K-ow, suggesting that metabolism of the higher K-ow compounds was occurring. These results support the conc lusion that mayflies and dreissenids play major roles in the transfer of PA Hs and PCBs to upper trophic levels, and they demonstrate that the exposure dynamics of PAHs and PCBs are different in the benthic components of aquat ic food webs.