Mercury in Arctic marine ecosystems: Sources, pathways and exposure

Environment Canada, Aquatic Contaminants Research Division, 867 Lakeshore Dr, Burlington, ON, Canada L7R 4A6. Electronic address: .
Environmental Research (Impact Factor: 4.37). 10/2012; 119. DOI: 10.1016/j.envres.2012.08.012
Source: PubMed


Mercury in the Arctic is an important environmental and human health issue. The reliance of Northern Peoples on traditional foods, such as marine mammals, for subsistence means that they are particularly at risk from mercury exposure. The cycling of mercury in Arctic marine systems is reviewed here, with emphasis placed on the key sources, pathways and processes which regulate mercury levels in marine food webs and ultimately the exposure of human populations to this contaminant. While many knowledge gaps exist limiting our ability to make strong conclusions, it appears that the long-range transport of mercury from Asian emissions is an important source of atmospheric Hg to the Arctic and that mercury methylation resulting in monomethylmercury production (an organic form of mercury which is both toxic and bioaccumulated) in Arctic marine waters is the principal source of mercury incorporated into food webs. Mercury concentrations in biological organisms have increased since the onset of the industrial age and are controlled by a combination of abiotic factors (e.g., monomethylmercury supply), food web dynamics and structure, and animal behavior (e.g., habitat selection and feeding behavior). Finally, although some Northern Peoples have high mercury concentrations of mercury in their blood and hair, harvesting and consuming traditional foods have many nutritional, social, cultural and physical health benefits which must be considered in risk management and communication.

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    • "This finding extends the geographic limits of the trend previously observed in multiple tissues of different bird species in the Arctic (e.g., Braune et al., 2002; Akearok et al., 2010; Øverjordet et al., 2015). Increasing Hg in eggs of marine birds at higher latitudes is driven by complex environmental factors including source Hg from local geology, global atmospheric deposition patterns, air and ocean circulation patterns , and climate-influenced retention of Hg in Arctic ice reservoirs (see Kirk et al., 2012, and references therein). Despite that Hg represents an issue for wildlife health in the northeastern USA and Nova Scotia regions (e.g., Goodale et al., 2008), the maximum level of Hg in Nova Scotia eider eggs (0.16 μg/g ww) was similar to that found in Maine (0.18 μg/g ww; Mierzykowski et al., 2005) and was 60% lower than the " no adverse effect " level (0.4 μg/g ww) determined for a variety of bird species (Shore et al., 2011). "
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    ABSTRACT: We provide the first report on trace element concentrations in eggs of common eiders (Somateria mollissima), a coastal benthic foraging sea duck, from Nova Scotia, Canada, and compare those to known values from this species elsewhere. Most trace elements of toxicological concern (Hg, Se, Cd, Cu, Zn) were lower in eider eggs from Nova Scotia than from eider eggs collected farther north in Canada, although As was elevated. Our data provide strong support for a pattern of increasing Hg at higher latitudes for this species.
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    • "The presence of persistent organic pollutants (POPs) and metals in the blood and other tissues of people from the Canadian Arctic and other circumpolar nations is well documented. Although there are natural and point sources of these chemicals (Kirk et al., 2012), global pollution and long-range atmospheric transportation are the main sources in the Arctic (Macdonald et al., 2000). Because of their physical–chemical properties, these chemicals can biomagnify through the marine food web system and can reach high concentrations in predatory species such as marine mammals (Borgå et al., 2004; Braune et al., 2005). "
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    ABSTRACT: Aboriginal peoples in the Canadian Arctic are exposed to persistent organic pollutants (POPs) and metals mainly through their consumption of a traditional diet of wildlife items. Recent studies indicate that many human chemical levels have decreased in the north, likely due to a combination of reduced global chemical emissions, dietary shifts, and risk mitigation efforts by local health authorities. Body burdens for chemicals in mothers can be further offset by breastfeeding, parity, and other maternal characteristics. We have assessed the impact of several dietary and maternal covariates following a decade of awareness of the contaminant issue in northern Canada, by performing multiple stepwise linear regression analyses from blood concentrations and demographic variables for 176 mothers recruited from Nunavut and the Northwest Territories during the period 2005-2007. A significant aboriginal group effect was observed for the modeled chemicals, except for lead and cadmium, after adjusting for covariates. Further, blood concentrations for POPs and metals were significantly associated with at least one covariate of older age, fewer months spent breastfeeding, more frequent eating of traditional foods, or smoking during pregnancy. Cadmium had the highest explained variance (72.5%) from just two significant covariates (current smoking status and parity). Although Inuit participants from the Northwest Territories consumed more traditional foods in general, Inuit participants from coastal communities in Nunavut continued to demonstrate higher adjusted blood concentrations for POPs and metals examined here. While this is due in part to a higher prevalence of marine mammals in the eastern Arctic diet, it is possible that other aboriginal group effects unrelated to diet may also contribute to elevated chemical body burdens in Canadian Arctic populations. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.
    Full-text · Article · May 2015 · Science of The Total Environment
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    • "Sediments collected in the Barents Sea contained little total mercury (3–5 ng/g d.w.), which corresponds to the lowest values observed in the Beaufort Shelf (1–130 ng/g) and along the Greenland coast (4–280 ng/l) (Asmund and Nielsen, 2000; Kirk et al., 2012 "
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    ABSTRACT: The European Arctic, including the Svalbard archipelago, receives mercury loads due to long range atmospheric transport, local contamination, melting of glaciers and as a result of bedrock weathering. Few studies have been devoted to the contamination history and sources of sedimentary mercury in the Svalbard area. This knowledge gap is addressed in this study. Concentrations of total mercury (10-80ng/g), fractions of mercury differing with affinity to the sediment matrix (88-97% refractory, 3-12% mobile), organic and methyl mercury (100-500pg/g) were measured in surface and subsurface sediments in the Spitsbergen fjords and in the Barents Sea off Svalbard. The atmospheric mercury signal can be observed in the Barents Sea, while in the Svalbard fjords it is strongly modified by supply of mercury from natural sources that may include weathering of rocks and glaciers melting, all modified by organic matter supply. Sedimentary methyl mercury concentrations seem to be dependent on environmental factors affecting mercury methylation rather than on location of sampling stations. Copyright © 2014 Elsevier Ltd. All rights reserved.
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