title: Blood and Hair Mercury Concentrations in the Pacific Harbor Seal (Phoca vitulina richardii) Pup: Associations with Neurodevelopmental Outcomes.
abstract: Monomethylmercury (MeHg(+)) is an environmental pollutant, which at sufficiently high exposures, has induced neurotoxicosis in several animal species, including humans. Adverse neurological effects due to gestational exposure are of particular concern as MeHg(+) readily crosses the blood-brain and placental barriers. The degree to which environmental concentrations in marine prey affect free-living piscivorous wildlife, however, remains largely undetermined. We examined associations of gestational exposures to mercury on neurodevelopment and survival using hair and blood concentrations of total mercury ([THg]) in a stranded population of Pacific harbor seal pups from central California. A positive association was determined for the presence of abnormal neurological symptoms and increasing [THg] in blood (P = 0.04), but not hair. Neither hair nor blood [THg] was significantly associated with survival, or the neurodevelopmental milestone 'free-feeding', which was measured from the onset of hand-assisted feeding to the time at which pups were able to consume fish independently. Both hair and blood [THg] exceeded threshold values considered potentially toxic to humans and other mammalian wildlife species. The higher [THg] in blood associated with abnormal neurological symptoms may indicate an adverse effect of this pollutant on neurodevelopment in harbor seal pups. These data have broader implications with respect to human health and public policy as harbor seals and humans consume similar fish species, and it is possible that safeguard levels established for marine mammals could also extend to human populations that regularly consume fish.
authors: School of Public Health, University of Minnesota, 420 Delaware St SE Mmc88, Minneapolis, MN, 55455, USA. sammyv@mninter.net.|, 8601 Lincoln Blvd. #3317, Los Angeles, CA, 90045, USA. sammyv@mninter.net.
authors: Samala
authors: S
authors: Van Hoomissen
authors: The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, CA, 94965, USA.
authors: Frances M D
authors: FM
authors: Gulland
authors: The Marine Mammal Center, 2000 Bunker Road, Fort Cronkhite, Sausalito, CA, 94965, USA.
authors: Denise J
authors: DJ
authors: Greig
authors: Department of Veterinary Medicine, College of Natural Science and Mathematics, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
authors: J Margaret
authors: JM
authors: Castellini
authors: Department of Veterinary Medicine, College of Natural Science and Mathematics, University of Alaska Fairbanks, Fairbanks, AK, 99775, USA.
authors: Todd M
authors: TM
authors: O'Hara
mesh_terms: D000818:Animals; D002140:California; D005260:Female; D006197:Hair / Q000737:chemistry; D018811:Maternal Exposure / Q000009:adverse effects*; D008628:Mercury / Q000032:analysis* / Q000097:blood; D020262:Mercury Poisoning, Nervous System / Q000662:veterinary*; D046049:Phoca; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000633:toxicity*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury
keywords: harbor seal pup; mercury; neurodevelopment; rehabilitation; toxicological thresholds