Bioaccumulation of polychlorinated biphenyls in ranid frogs and northern water snakes from a hazardous waste site and a contaminated watershed

Livers of bullfrogs (Rana catesbeiana) from a polychlorinated biphenyl (PCB ) contaminated watershed and hazardous waste site located in Pickens County , South Carolina, contained significantly higher concentrations of PCBs (2. 33 and 2.26 ppm, respectively) than those from a reference site (0.05 ppm). Green frogs (R. clamitans) from the two contaminated sites also accumulate d higher levels of PCBs (2.37 and 3.88 ppm, respectively) than those from t he reference site (0.02 ppm). No temporal variation was observed in PCB con centrations of bullfrogs or green frogs from the contaminated sites between 1992 and 1993. Levels of PCBs in the livers of northern water snakes (Nero dia sipedon) were significantly higher in snakes from the contaminated wate rshed (13.70 ppm) than in those from the waste site (2.29 ppm) and two refe rence sites (2.50 and 1.23 ppm). When compared to frogs, significantly high er bioaccumulation occurred in water snakes from the contaminated watershed . No significant differences in PCB levels were found with respect to sex o r body size (snout-vent length (SVL) or body mass) for frogs or snakes. PCB s were detected also in eggs of both frogs and snakes. Results of this stud y provide baseline data and document the bioaccumulation of PCB residues in frog and snake tissues; however, the significance of these tissue residues to reproduction, survival, growth/development, and population dynamics in contaminated habitats is unknown. (C) 2000 Elsevier Science Ltd. All rights reserved.