Transplacental Transfer of PCBs and Chlorinated Hydrocarbon Pesticides from the Pregnant Striped Dolphin (Stenella coeruleoalba) to Her Fetus

Abstract

Transplacental transfer of chlorinated hydrocarbons such as PCBs, DDT compounds, HCH isomers and HCB was determined in a pregnant striped dolphin just before parturition. The transfer rates of chlorinated hydrocarbons in the striped dolphin through parturition were estimated as follows: PCBs 4.0%, ΣDDT 4.7%, ΣHCH 8.9% and HCB 9.4%. The concentration ratios of chlorinated hydrocarbons in the blubber of the fetus to that of the mother dolphin were found to be in the order of HCB > HCH isomers > DDT compounds > PCBs. Especially in PCB congeners, these ratios gradually decreased with the increase of chlorine atoms substituted in biphenyls. These observations indicate that the more lipophilic chemicals, such as higher chlorinated biphenyls and DDT compounds, are less transferable from mother to fetus. The transfer characteristics of chlorinated hydrocarbons can be explained by their equilibrium partitionings between blood and blubber, resulting from the differences of lipid compositions in each.