title: Bioavailable mercury cycling in polar snowpacks.
abstract: Polar regions are subject to contamination by mercury (Hg) transported from lower latitudes, severely impacting human and animal health. Atmospheric Mercury Depletion Events (AMDEs) are an episodic process by which Hg is transferred from the atmospheric reservoir to arctic snowpacks. The fate of Hg deposited during these events is the subject of numerous studies, but its speciation remains unclear, especially in terms of environmentally relevant forms such as bioavailable mercury (BioHg). Here, using a bacterial mer-lux biosensor, we report the fraction of newly deposited Hg at the surface and at the bottom of the snowpack that is bioavailable. Snow samples were collected over a two-month arctic field campaign in 2008. In surface snow, BioHg is related to atmospheric Hg deposition and snow fall events were shown to contribute to higher proportions of BioHg than AMDEs. Based on our data, AMDEs represent a potential source of 20 t.y(-1) of BioHg, while wet and dry deposition pathways may provide 135-225 t.y(-1) of BioHg to Arctic surfaces.
authors.affiliation: Laboratoire de Glaciologie et Géophysique de l'Environnement, CNRS - Université Joseph Fourier Grenoble, 54 Rue Molière, 38400 St Martin d'Hères, France.
authors.forename: Catherine
authors.initials: C
authors.lastname: Larose
authors.forename: Aurélien
authors.initials: A
authors.lastname: Dommergue
authors.forename: Nicolas
authors.initials: N
authors.lastname: Marusczak
authors.forename: Jacques
authors.initials: J
authors.lastname: Coves
authors.forename: Christophe P
authors.initials: CP
authors.lastname: Ferrari
authors.forename: Dominique
authors.initials: D
authors.lastname: Schneider
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry*; D000397:Air Pollution / Q000706:statistics & numerical data; D001110:Arctic Regions; D055669:Ecological and Environmental Phenomena; D004784:Environmental Monitoring; D008628:Mercury / Q000032:analysis / Q000737:chemistry*; D012914:Snow / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D008628:Mercury