Subchronic effects of five di-ortho PCB congeners on survival, growth and reproduction in the fathead minnow Pimephales promelas

The effects of five di-ortho polychlorinated biphenyl (PCB) congeners (International Union of Pure and Applied Chemists numbers 52, 101, 138, 153, 180) on survival, growth, and reproduction in the fathead minnow, Pimephales promelas, were determined. Fish were exposed to one of two nominal concentrations (2.5 mu g/L [low] and 25.0 mu g/L [high]) of each congener for a total of 13 weeks (7-week prespawning period plus 6-week spawning period) under flow-through conditions using methanol as a carrier solvent. At termination, P. promelas survival was high (92.6-100%) in all PCB congener treatments. PCB congeners had no significant (p <0.05) sublethal effects on reproductive success within the concentration range examined. The total number of eggs, clutch size, number of clutches, percent hatchability, and presence of terata in offspring were not significantly affected. Reproductive success was slightly but not significantly enhanced in the solvent control and high (25 mu g/L) treatment concentrations for congeners 52, 101, 138, and 153. Growth expressed as wet weight was not affected for both adult males or females. Male lengths were not significantly affected but female lengths were significantly reduced when exposed to congeners 101, 138, 153, and 180. Pimephales promelas accumulated substantial amounts of all PCBs, with tissue concentrations ranging from 13 to 183 mg/kg wet weight at termination in PCB-exposed fish. These tissue residues are one to several orders of magnitude greater than those reported for these congeners in aquatic biota previously collected in industrial waterways of the Great Lakes, Several di-ortho PCB congeners frequently found in aquatic biota showed minimal adverse effects on fathead minnow survival, growth, and reproduction even though bioaccumulation of these congeners was substantial.