title: Determination of monomethylmercury and dimethylmercury in the Arctic marine boundary layer.
abstract: Our understanding of the biogeochemical cycling of monomethylmercury (MMHg) in the Arctic is incomplete because atmospheric sources and sinks of MMHg are still unclear. We sampled air in the Canadian Arctic marine boundary layer to quantify, for the first time, atmospheric concentrations of methylated Hg species (both MMHg and dimethylmercury (DMHg)), and, estimate the importance of atmospheric deposition as a source of MMHg to Arctic land- and sea-scapes. Overall atmospheric MMHg and DMHg concentrations (mean ± SD) were 2.9 ± 3.6 and 3.8 ± 3.1 (n = 37) pg m(-3), respectively. Concentrations of methylated Hg species in the marine boundary layer varied significantly among our sites, with a predominance of MMHg over Hudson Bay (HB), and DMHg over Canadian Arctic Archipelago (CAA) waters. We concluded that DMHg is of marine origin and that primary production rate and sea-ice cover are major drivers of its concentration in the Canadian Arctic marine boundary layer. Summer wet deposition rates of atmospheric MMHg, likely to be the product of DMHg degradation in the atmosphere, were estimated at 188 ± 117.5 ng m(-2) and 37 ± 21.7 ng m(-2) for HB and CAA, respectively, sustaining MMHg concentrations available for biomagnification in the pelagic food web.
authors.affiliation: Environmental & Life Sciences Graduate Program, Trent University , 1600 West Bank Drive, Peterborough, Ontario, K9J 7B8, Canada.
authors.forename: Pascale A
authors.initials: PA
authors.lastname: Baya
authors.forename: Michel
authors.initials: M
authors.lastname: Gosselin
authors.forename: Igor
authors.initials: I
authors.lastname: Lehnherr
authors.forename: Vincent L
authors.initials: VL
authors.lastname: St Louis
authors.forename: Holger
authors.initials: H
authors.lastname: Hintelmann
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001110:Arctic Regions; D001272:Atmosphere; D002170:Canada; D020387:Food Chain; D046448:Ice Cover / Q000737:chemistry*; D008628:Mercury / Q000032:analysis; D008767:Methylmercury Compounds / Q000032:analysis*; D012621:Seasons; D012623:Seawater; D014874:Water Pollutants, Chemical / Q000032:analysis
chemical_list: D000393:Air Pollutants; D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; C073972:dimethyl mercury; D008628:Mercury