Polychlorinated biphenyls, organochlorine pesticides, tris (4-chlorophenyl)methane, and tris(4-chlorophenyl)methanol in livers of small cetaceans stranded along Florida coastal waters, USA

Concentrations of polychlorinated biphenyl congeners (PCBs) and organochlor ine pesticides were determined in the livers of bottlenose dolphins, Atlant ic spotted dolphins, and pygmy sperm whales found stranded along the coasta l waters of Florida, USA, during 1989 to 1994. The PCBs were the most predo minant contaminants followed in order by DDTs, chlordanes, tris(4-chlorophe nyl)methane (TCPMe), tris(4-chlorophenyl)methanol (TCPMOH), hexachlorobenze ne, and hexachlotocyclohexane isomers. Among the cetaceans analyzed, organo chlorine concentrations were greatest in bottlenose dolphins followed by At lantic spotted dolphins and pygmy sperm whales. Hexa- and heptachlorobiphen yls were the predominant PCB congeners found in the livers of dolphins. Pat terns of relative concentrations of PCB congeners varied among individual b ottlenose dolphins. A few individuals contained predominant concentrations of octa- (CB-199, 196/201) and nonachlorobiphenyl (CB-206, 208) congeners, which suggested exposure to the highly chlorinated PCB formulation, Aroclor ((R)) 1268, a contaminant at a coastal site in Georgia bordering northern F lorida. The estimated 2,3,7,8-tetrachlorodibenzo-p-dioxin toxic equivalents (TEQs) of coplanar PCBs in bottlenose dolphins were 170 to 18,000 pg/g, li pid weight (mean: 5,400 pg/g) with mono-ortho congeners 118, 105, and 156 c ontributing more than 80% of the TEQs. The ratios of CB-169 to CB-126 in ce tacean livers were linearly related to total PCB concentrations, which sugg ested a strong induction of microsomal monooxygenase enzymes in the liver. The hepatic concentrations of TCPMe and TCPMOH in bottlenose dolphins and A tlantic spotted dolphins were greater than those in the blubber of marine m ammals of various regions, which suggested the presence of sources for thes e chemicals along the Atlantic coast of Florida.