Biochemical responses based on cytochrome P450 induction in chinook salmon (Oncorhynchus tshawytscha) exposed to bleached kraft mill effluent on the Fraser River

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1996

Authors

Wilson, Joanna Yvonne

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Abstract

Juvenile chinook salmon were collected from sites on the upper Fraser River downstream of bleached kraft pulp mills and municipal outfalls. Ethoxyresorufin-O-deethylase activity (EROD), CYP I Al density, and DN A adduct concentrations were measured in liver tissue. Liver histopathology was performed. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) were measured in carcasses. Polyaromatic hydrocarbon (PAH) metabolites were measured in bile. Biochemical, but not histopathological, responses were significantly different from those in controls at nearly all sites. Biochemical responses were not correlated with any of the contaminants analyzed. Fish sampled closest to effluent discharge showed the weakest responses. In fish experimentally exposed to effluent, significant increases in biological effects were seen at 2% (and higher) effluent concentrations. These results indicate that fish at this site may not be exposed to effluent concentrations previously thought, perhaps suggesting that chinook are mobile during winter months. Biological responses are not caused by the organic contaminants measured.

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