title: Transplacental Transfer of Polychlorinated Biphenyls, Polybrominated Diphenylethers, and Organochlorine Pesticides in Ringed Seals (Pusa hispida).
abstract: The transplacental transfer of persistent organic pollutants in marine mammals takes place at a formative developmental period, thereby exposing the fetus to endocrine-disrupting compounds. We evaluated the transplacental transfer of polychlorinated biphenyls (PCBs), polybrominated diphenylethers (PBDEs), and organochlorine pesticides (OCPs) in five pregnant ringed seals in Northern Labrador, Canada. PCBs, PBDEs, and OCPs were transferred from the mother to the fetus with average concentrations in the fetuses ranging from 0.3 ng/g lipid weight (lw) of mirex to 94 ng/g lw of PCBs. The average percent transferred to the blubber in the fetus was very low with <0.02 % for each of the compounds studied. Based on relationships observed, transfer for full-term fetuses is estimated to range from 0.03 to 0.27 %. Log K(ow) explained the transfer of PCBs (r (2) = 0.67, p < 0.001) and OCPs (r (2) = 0.62, p < 0.001) with those PCB congeners and OCP compounds having a log K(ow) of <6.0 and 4.6, respectively, because they are preferentially transferred to the fetus. Adult females transferred a contaminant mixture to their fetuses, which correlated with estimated fetal age (p < 0.001; r (2) = 0.697), with younger fetuses showing a greater proportion of compounds with low K(ow) compared with later-term fetuses. The implications for the prenatal exposure to these developmental toxicants remains unknown because current toxicity thresholds in marine mammals have only been derived from juveniles or adults.
authors.affiliation: Raincoast Conservation Foundation, P.O. Box 2429, Sidney, BC, V8L 3Y3, Canada. tanya@raincoast.org.|Memorial University of Newfoundland, St. John's, NL, A1B 3X9, Canada. tanya@raincoast.org.
authors.forename: T M
authors.initials: TM
authors.lastname: Brown
authors.affiliation: Ocean Pollution Research Program, Vancouver Aquarium Marine Science Center, P.O. Box 3232, Vancouver, BC, V6B 3X8, Canada.
authors.forename: P S
authors.initials: PS
authors.lastname: Ross
authors.affiliation: Environmental Sciences Group, Royal Military College of Canada, P.O. Box 17000, Stn Forces, Kingston, ON, K7K 7B4, Canada.
authors.forename: K J
authors.initials: KJ
authors.lastname: Reimer
mesh_terms: D000818:Animals; D052244:Endocrine Disruptors / Q000378:metabolism; D004784:Environmental Monitoring; D005260:Female; D006843:Hydrocarbons, Chlorinated / Q000378:metabolism*; D008431:Maternal-Fetal Exchange; D009523:Newfoundland and Labrador; D010575:Pesticides / Q000378:metabolism*; D011075:Polybrominated Biphenyls / Q000378:metabolism; D011078:Polychlorinated Biphenyls / Q000378:metabolism*; D011247:Pregnancy; D046048:Seals, Earless; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D052244:Endocrine Disruptors; D006843:Hydrocarbons, Chlorinated; D010575:Pesticides; D011075:Polybrominated Biphenyls; D014874:Water Pollutants, Chemical; D011078:Polychlorinated Biphenyls