IMPAIRED INDUCIBILITY OF XENOBIOTIC AND ANTIOXIDANT RESPONSES IN RAINBOW-TROUT EXPOSED TO POLYCHLORINATED BIPHENYL CONTAMINATED SEDIMENTS IN THE ST-LAWRENCE-RIVER

The uptake of polychlorinated biphenyl (PCB) congeners was monitored i n rainbow trout caged during the dredging operation of General Motors at its Superfund site in Massena, New York. Trout were caged at the GM site and at a reference (control) site for two time periods (21 and 4 2 days). The PCB loading was compared with the inducibility of phase I and II enzymes and antioxidant defenses in the fish tissues. Muscle t otal PCB loading resulted in 117- (21 d) and 34-fold (42 d) difference s between trout from the GM and control sites. Hepatic and renal ethox yresorufin O-deethylase (EROD) activities remained unchanged in trout caged at the different sites. A decrease in hepatic glutathione S-tran sferase was noted in fish caged at the GM site after 42 days. Total gl utathione (TGSH) and antioxidant enzymes demonstrated insignificant ch anges in trout tissues from the different sites, although muscle TGSH content was significantly lower in trout caged at the GM than at the c ontrol site after 42 days. These observations suggest that continuous PCB exposure results in impaired inducibility of biochemical detoxicat ion parameters and no adaptive response in rainbow trout. Copyright (C ) 1996 Elsevier Science Ltd