Polychlorinated Biphenyl Congeners and Chlorinated Pesticides in Fish from the Yamaska River Basin, Quebec

Abstract Bottom-feeding fish from the Yamaska River in Quebec and its major tributary, the Noire River (5 female specimens from each site), were analyzed for residues of organochlorine pesticides and PCB congeners in liver, spleen, gonad, kidney, gall bladder, visceral fat and dorsal muscle. Significant quantities of target chemicals were found in the basic extracts as well as the acidic extracts of these fish tissues, suggesting that acidic digestion followed by saponification and extraction with an organic solvent may provide a more complete recovery of organic contaminants residues from biological tissues than conventional techniques. Residues were highest and least variable in fat, therefore this tissue was used to compare patterns of contamination between sites. Fish from the Noire River contained 6X as much ZDDT and 3X as much ZPCBs in their fat than fish from the Yamaska River (2800 versus 440 ng/g and 1700 versus 500 ng/g wet weight, respectively), but no differences between sites were observed for dieldrin, lindane or heptachlor epoxide. Noire River fish exhibited a less degraded pattern of PCB contamination, with proportionately more penta- (15% versus 4%) and less hexa- and heptachlorobiphenyls (70% versus 81%) plus nine more congeners in their fat. They also contained a higher proportion of the toxic congeners (28% versus 17%), had lower lipid contents and were in poorer condition. Thus, further investigation of the sources and effects of persistent organic contaminants in the Noire River basin may be warranted.