title: Mercury Accumulation in Harbour Seals from the Northeastern Pacific Ocean: The Role of Transplacental Transfer, Lactation, Age and Location.
abstract: Mercury (Hg) bioaccumulates in the aquatic food chain in the form of methylmercury, a compound well known for its neurotoxicity. We analyzed total mercury (THg) in hair collected from 209 harbour seals captured at 10 sites in British Columbia (Canada) and Washington State (USA) between 2003 and 2010. In addition, laser ablation inductively-coupled plasma mass spectrometry (LA-ICP-MS) allowed for a highly refined analysis of THg accumulation over time by examining nine whiskers taken from 4- to 6-week-old pups. We estimate that THg concentrations in pups increased sharply at a point corresponding to mid- to late gestation of their time in utero (4.7 ± 0.8 and 6.6 ± 1.3 µg/g dry weight (dw), respectively), and then again at the onset of nursing (8.1 ± 1.3 µg/g dw). These abrupt changes highlight the importance of both pre- and post-natal THg transfer from the mother to the growing fetus and the newborn pup. While THg levels varied among sites, hair analyses from seals collected at the same site demonstrated the influence of age in THg accumulation with pups (5.3 ± 0.3 µg/g) and juveniles (4.5 ± 0.5 µg/g) having lower levels than those in adults (8.3 ± 0.8 µg/g). Our results revealed that 33 % of the pups sampled (n = 167) had THg levels that surpassed a mammalian hair threshold for neurochemical alterations. This study suggests that Hg could represent a health concern to marine wildlife, especially as atmospheric emissions of this toxic element from human activities in the Pacific Rim and worldwide continue.
authors.affiliation: School of Earth and Ocean Sciences, University of Victoria, Victoria, BC, V8W 3P6, Canada.|Ocean Pollution Research Program, Coastal Ocean Research Institute, Vancouver Aquarium Marine Science Center, P.O. Box 3232, Vancouver, BC, V6B 3X8, Canada.
authors.forename: Marie
authors.initials: M
authors.lastname: Noël
authors.affiliation: Washington Department of Fish and Wildlife, 7801 Philips Road, Lakewood, WA, 98498, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Jeffries
authors.affiliation: Washington Department of Fish and Wildlife, 7801 Philips Road, Lakewood, WA, 98498, USA.
authors.forename: Dyanna M
authors.initials: DM
authors.lastname: Lambourn
authors.affiliation: School of Earth and Ocean Sciences, University of Victoria, Victoria, BC, V8W 3P6, Canada.|Artisanal Gold Council, 101-732 Cormorant St., Victoria, BC, V8W 4A5, Canada.
authors.forename: Kevin
authors.initials: K
authors.lastname: Telmer
authors.affiliation: Institute of Ocean Sciences, Fisheries and Oceans Canada, P.O. Box 6000, Sidney, BC, V8L 4B2, Canada.
authors.forename: Robie
authors.initials: R
authors.lastname: Macdonald
authors.affiliation: Ocean Pollution Research Program, Coastal Ocean Research Institute, Vancouver Aquarium Marine Science Center, P.O. Box 3232, Vancouver, BC, V6B 3X8, Canada. Peter.Ross@VanAqua.org.
authors.forename: Peter S
authors.initials: PS
authors.lastname: Ross
mesh_terms: D000818:Animals; D001955:British Columbia; D004784:Environmental Monitoring; D005260:Female; D006197:Hair / Q000737:chemistry; D007774:Lactation; D008297:Male; D008431:Maternal-Fetal Exchange; D008628:Mercury / Q000032:analysis / Q000378:metabolism*; D010140:Pacific Ocean; D046049:Phoca; D011247:Pregnancy; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury