Transplacental transfer of organochlorines in California sea lions (Zalophus californianus)

The transplacental transfer of organochlorines (OCs) in California sea lions (Zalopluts californianus) was investigated by analyzing blubber samples from 20 female sea lions and their fetuses during the last trimester of pregnancy. A rapid, high-performance liquid chromatographic, photodiode-array method was used to measure blubber concentrations of polychlorinated biphenyls (PCBs), including dioxin-like congeners, as well as DDTs and hexachlorohenzene. Summed values of PCBs (Sigma PCBs), of DDTs (Sigma DDTs), and of PCB toxic equivalents (Sigma PCB TEQs) were calculated from these data. The ratios of mean blubber concentrations of fetal IPCBs to maternal blubber concentrations of Sigma PCBs were 0.45 by wet weight and 0.97 by lipid weight, but these ratios varied widely among, mother-fetus pairs. Mean ratios of fetal Sigma DDTs to maternal Sigma DDTs were 0.53 by wet weight and 1.12 by lipid weight. Fetuses were classified into two age group, based on date of recovery, to examine differences it OC transfer because of gestational age. Fetal to maternal ratios for individual PCB congeners. DDT compounds, and Sigma PCBs, Sigma DDTs, and Sigma PCB TEQs were lower among premature compared with late-term fetuses. These ratios increased for both groups as the logarithmic n-octanol/water partition coefficient (log K-ow) for each compound decreased. Linear predictions for Sigma PCB and Sigma DDT concentrations in fetal blubber Could he obtained using the Sigma PCB and Sigma DDT concentrations in maternal blubber, maternal and fetal blubber lipid content. maternal mass, and maternal age. Fetal TEQ was explained by maternal TEQ and maternal age. The ability to predict contaminant concentrations in fetal blubber front maternal parameters is important for developing risk assessment models for marine mammals.