The use of selected physiological parameters as indicators of polychlorinated biphenyl exposure of rainbow trout, Oncorhynchus mykiss.

Abstract

Hatchery reared rainbow trout (Oncorhynchus mykiss) were caged at two locations in the St. Lawrence river near Cornwall, Ontario. One cage was anchored in an area of high polychlorinated biphenyl (PCB) contamination, within an iron enclosure near the General Motors Foundry at Massena, N.Y. during a dredging operation designed to remove PCB contaminated sediments from the river. A second control cage was placed in the Snye channel, known to have low PCB concentrations. Hatchery fish were sampled to provide a time 0 control, and fish from each site were collected following 21 and 41 day exposure. Plasma, muscle, bone, and liver were harvested and assayed to determine muscle PCB levels, plasma cortisol, electrolyte, lactate and glucose concentrations, bone calcium, muscle water and the activity of a variety of liver enzymes. Total PCB levels were significantly higher in fish muscle from the General Motors site but few differences were found in any of the physiological parameters. Levels of bone calcium decreased in fish exposed to high PCB levels, suggesting an effect of PCBs on either the thyroid or ultimobranchial bodies. Pyruvate kinase activity in the liver of PCB exposed fish suggests a shift in energy metabolism to a greater reliance on glycogenolysis. Both parameters require further study to determine the feasibility of their use as bioindicators of PCB stress.