ANALYSIS OF GULF-OF-MEXICO BOTTLE-NOSED DOLPHINS FOR ORGANOCHLORINE PESTICIDES AND PCBS

Organochlorine concentrations were determined in blubber samples from 33 Tursiops truncatus stranded on the Texas and Florida coastlines. Al l tissues had measurable concentrations of 4,4'-DDE (0.18-70.7 mu g/g lipid weight) and Sigma PCB (4.1-149 mu g/g lipid weight). Pesticide a nd PCB concentrations were similar to those reported in Tursiops trunc atus from the Atlantic coast of the United States and the southeast co ast of Africa. Organochlorine concentrations were highest in mature ma les, and differences in the Sigma PCB/Sigma DDT ratios between mature and immature males suggests a recent decrease in DDT uptake, related t o the commercial DDT ban in the US in 1971, as well as dietary differe nces between younger and older animals. Analysis of a female and her c alf indicate that females reduce their own organochlorine body burden through transplacental transfer. However, no reduction of some higher molecular weight PCBs was found. Transplacental transfer rates of 5-1% for Sigma DDT and 3.7% for Sigma PCB were determined based on a stran ded female and her full term, unborn calf: Predictions of uptake and d epuration rates of organochlorines based on gender in Tursiops truncat us agree with clearance rates from previous studies.