ARS | Publication request: Organic halogenated contaminants in mother-fetus pairs of harbor seals (Phoca vitulina richardii) from Alaska, 2000-2002

Submitted to: Journal of Hazardous Materials
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 21, 2012
Publication Date: April 28, 2012
Citation: Wang, D., Atkinson, S., Hoover-Miller, A., Shelver, W.L., Li, Q.X. 2012. Organic halogenated contaminants in mother-fetus pairs of harbor seals (Phoca vitulina richardii) from Alaska, 2000-2002. Journal of Hazardous Materials. 223-224:72-78.

Interpretive Summary: In this study, six pregnant harbor seals were hunted and harvested in the northern Gulf of Alaska. The more numerous juvenile, male, or non-pregnant harvested animals could not be part of this study. The small number of animals in this study is due to the difficulty of collecting the required pregnant females from the wild during a relatively short hunting season. The focus of the study was to examine how certain pollutants were distributed to the fetus. Liver, placenta, and fat samples were collected from the mother and liver, brain, and fat were collected from the corresponding fetus. A group of pollutants were measured in these tissues using an instrument called GC-MS (Gas chromatography- mass spectrometry) that allows separation of many compounds that are individually identified and the amounts present measured. Our results showed that nearly all of the industrial chemicals we studied were transferred from the mother to the fetus during pregnancy although the precise amount varied dependent on the tissue as well as the chemical class of the compound.

Technical Abstract: Environmental stressors may interfere with foraging, survival and reproduction of marine mammals resulting in marine mammal population decline. In this study, organic halogenated pollutants [OHs, including organochlorine pesticides, polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs) and polybrominated diphenyl ethers (PBDEs)] were measured in tissues of six harbor seal mother–fetus pairs that were hunted for subsistance from the Northern Pacific Ocean. The average concentration of OHs (n=6) was 309.3 ng/g ww in maternal blubber, 11.6 ng/g ww in maternal liver, 130 ng/g ww in placenta, 11.4 ng/g ww in fetal liver, and 11.0 ng/g ww in fetal brain. The data suggest that significant amounts of these contaminants were transferred from mother harbor seals to fetuses during pregnancy and distributed among fetal organs. Breakdown of OHs into components demonstrated the distribution into the tissues depended on the chemical group and sometimes on the specific compound in the group as well as the target organ. Hexachlorocyclohexane (HCH), hexachlorobenzene (HCB), and low chlorinated congeners of PCBs showed increased concentrations in fetuses compared to p,p'-DDE, PCNs, PBDEs and highly chlorinated congeners of PCBs which were retained in the mother to a greater extent. Prenatal transfer of OHs could pose a threat to the critical early development of the fetuses; whereas the retention of toxic congeners in the mother seals may reflect the protective role of the placenta.