Chemical exposure dynamics of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) in green frog (Rana clamitans ) and bullfrog (Rana catesbeiana) tadpoles

Studies were conducted to determine the effects of different environments and temperatures on chemical exposure dynamics in tadpoles. In the first study, green frog tadpoles (Rana clamitans) were dosed with Performance Reference Compound polychlorinated biphenyls (PRC PCBs) and placed into agricultural, municipal and reference watersheds near Windsor, Ontario, Canada. PRC PCBs were eliminated significantly faster than in previous laboratory studies, with elimination rate coefficients between 0.200 and 1.295 day-1. Tadpoles reached steady state within 23 days and tracked differences in chemical bioavailability among sites. The elimination of PRC PCBs and DDT were evaluated in green frog and bullfrog (Rana catesbeiana) tadpoles at two temperatures (18 and 25°C). Temperature had no effects on elimination of PRCs or DDT. These results indicate that tadpoles are tolerant of moderate temperature changes in this range. Green frogs eliminated PRCs and DDT faster than bullfrogs (e.g. PRC 43 at 1.278 versus 0.421 day-1)