title: Importance of open marine waters to the enrichment of total mercury and monomethylmercury in lichens in the Canadian High Arctic.
abstract: Caribou, which rely on lichens as forage, are a dietary source of monomethylmercury (MMHg) to many of Canada's Arctic Aboriginal people. However, little is understood about the sources of MMHg to lichens in the High Arctic. We quantified MMHg, total mercury (THg) and other chemical parameters (e.g., marine and crustal elements, δ(13)C, δ(15)N, organic carbon, calcium carbonate) in lichen and soil samples collected along transects extending from the coast on Bathurst and Devon islands, Nunavut, to determine factors driving lichen MMHg and THg concentrations in the High Arctic. Lichen MMHg and THg concentrations ranged from 1.41 to 17.1 ng g(-1) and from 36.0 to 361 ng g(-1), respectively. Both were highly enriched over concentrations in underlying soils, indicating a predominately atmospheric source of Hg in lichens. However, MMHg and THg enrichment at coastal sites on Bathurst Island was far greater than on Devon Island. We suggest that this variability can be explained by the proximity of the Bathurst Island transect to several polynyas, which promote enhanced Hg deposition to adjacent landscapes through various biogeochemical processes. This study is the first to clearly show a strong marine influence on MMHg inputs to coastal terrestrial food webs with implications for MMHg accumulation in caribou and the health of the people who depend on them as part of a traditional diet.
authors: †Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors: K A
authors: KA
authors: St Pierre
authors: †Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors: V L
authors: VL
authors: St Louis
authors: ‡Aquatic Ecosystem Protection Research Division, Environment Canada, Burlington, Ontario L7R 4A6, Canada.
authors: J L
authors: JL
authors: Kirk
authors: §Department of Geography, University of Toronto Mississauga, Mississauga, Ontario L5L 1C6, Canada.
authors: I
authors: I
authors: Lehnherr
authors: †Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors: S
authors: S
authors: Wang
authors: †Department of Biological Sciences, University of Alberta, Edmonton, Alberta T6G 2E9, Canada.
authors: C
authors: C
authors: La Farge
mesh_terms: D001110:Arctic Regions; D004784:Environmental Monitoring; D062312:Islands; D008011:Lichens / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D008767:Methylmercury Compounds / Q000032:analysis; D020957:Nunavut; D025341:Principal Component Analysis; D012623:Seawater / Q000737:chemistry*; D012987:Soil / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008767:Methylmercury Compounds; D012987:Soil; D014874:Water Pollutants, Chemical; D008628:Mercury