Evaluation of Persistent Contaminant Levels in Great Lakes Salmon Eggs

Abstract

Chinook, coho, and steelhead eggs collected in 2006 from Lake Ontario, L. Erie, L. Michigan, and L. Superior were analyzed by gas chromatography for congener-specific polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and select organochlorine pesticides (OCs). Across lake comparisons for total PCB, total DDT, and total PBDE indicated a consistent trend in contaminant concentrations in which Lake Michigan > Lake Ontario > Lake Erie > Lake Superior. The contaminants Mirex and octachlorostyrene (OCS) were found not to be consistent with this trend, but were instead found to exist in higher concentrations in Lake Ontario in relation to the other Great Lakes. PCB chlorination patterns, as indicated by the average number of chlorines per biphenyl (Avg Cl/BP) were compared within species. The PCB chlorination pattern in chinook eggs was found to be similar for both Lake Michigan (5.47) and Lake Ontario (5.43). The PCB chlorination pattern in coho eggs was notably different in Lake Superior (5.78) than in Lake Ontario (5.41).