Uptake of organochlorines (chlorobiphenyls, dieldrin; total PCB & DDT) in bottlenose dolphins (Tursiops truncatus) from Cardigan Bay, West Wales

High concentrations of organochlorine compounds (particularly PCB and chlorobiphenyls) have been found in three bottlenose dolphins from the vicinity of New Quay in West Wales. Although few in number, the animals ranged in age from 10 months to 23 years. The occurrence of high contaminant concentrations in all of these animals suggests that a high level of uptake of these compounds occurs in food after weaning as well as by transfer from mother to calf. In order to investigate this further we have tried to model the uptake using a bioenergetics-based approach. Using estimates of feeding rate we have calculated the concentrations of these contaminants in average prey items necessary to maintain the dolphin′s body burden during the juvenile growth stage. The data available to date are too few for a rigorous test of this approach, however these preliminary studies suggest that the contaminant concentrations in local food items analysed to date are not sufficiently high to explain the high concentrations found in dolphin blubber. Further information is needed on the contaminant burdens of bottlenose dolphins in Cardigan Bay, and of their relationship diet (including seasonal and migratory components), in order to validate this approach.