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

摘要

The uptake of polychlorinated biphenyl (PCB) congeners was monitored in 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 42 days). The PCB loading was compared with the inducibility of phase Ⅰ and Ⅱ enzymes and antioxidant defenses in the fish tissues. Muscle total PCB loading resulted in 117- (21 d) and 34-fold (42 d) differences between trout from the GM and control sites. Hepatic and renal ethoxyresorufin O-deethylase (EROD) activities remained unchanged in trout caged at the different sites. A decrease in hepatic glutathione S-transferase was noted in fish caged at the GM site after 42 days. Total glutathione (TGSH) and antioxidant enzymes demonstrated insignificant changes in trout tissues from the different sites, although muscle TGSH content was significantly lower in trout caged at the GM than at the control site after 42 days. These observations suggest that continuous PCB exposure results in impaired inducibility of biochemical detoxication parameters and no adaptive response in rainbow trout.