Spatial Trends and Historical Deposition of Mercury in Eastern and Northern Canada Inferred from Lake Sediment Cores

Muir, Derek C.G.; Wang, X.; Yang, Fan; Nguyen, Ngoc Thang; Jackson, Togwell A.; Evans, Marlene S.; Douglas, Marianne S. V.; Köck, Günter; Lamoureux, Scott F.; Pienitz, Reinhard; Smol, John P.; Vincent, Warwick F.; Dastoor, Ashu

doi:10.1021/es8035412

Cited by 190 publications

(209 citation statements)

References 42 publications

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“…In freshwater, however, significant increases in THg fluxes to sediments during the 20th century indicate that deposited atmospheric Hg has had an effect on Hg levels in lake sediments and, by extension, on freshwater Hg budgets in the Arctic. [21][22][23] Results from a recent study of marine sediments from Hudson Bay indicate THg concentrations increased during the 20th century. [24] Deposited Hg either enters aquatic environments (marine systems, melt ponds on sea ice, lakes or rivers) or remains in soils or the multi-year snow and ice found on glaciers and ice sheets (Fig.…”

Section: Since 1993 Prof Henrik Skov Has Worked As Principal Scientimentioning

confidence: 99%

“…Organic matter, which strongly binds Hg, [67] occurs at low concentrations in nearshore and deep-water sediments of High Arctic lakes (typically less than 10 % dry weight (DW), total organic carbon). [23,67,68] Spatial variations in sediment concentrations of THg and MeHg are in general strongly correlated with organic carbon content. [62,68,69] In Alaskan lakes, sediment MeHg concentrations were found to be strongly correlated with organic carbon content whereas inorganic Hg concentrations were related primarily to the focussing of fine-grained inorganic soil particles.…”

Section: Since 1993 Prof Henrik Skov Has Worked As Principal Scientimentioning

confidence: 99%

“…This finding is consistent with a synoptic scale study that reconstructed atmospheric Hg deposition rates from the sediments of many lakes across Arctic Canada and found no evidence for significant AMDE Hg loading in coastal lakes compared with those further inland. [23] The rate of long-term sequestration of mercury through burial in arctic sediment, soil, peat and ice archives For the purposes of this assessment, 'long-term' sequestration is defined as the removal of Hg from the biogeochemically active environment for periods likely to exceed several centuries. Over longer periods, from millennia to geological time scales, reworking of terrestrial archives, shallow coastal sediments and even deep ocean sediments by geomorphological processes associated with glacial and inter-glacial cycles and tectonic activity may remobilise long-term sequestered Hg.…”

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

“…The balance between increased Hg inputs and increased sequestration implies that most of the modern increase in Hg inputs to Hudson Bay was ultimately captured and buried in sediments. [253] For freshwater sediments, estimates of focus-corrected modern Hg fluxes, averaged over recent decades, are available for 76 lakes from Northern Canada, [23,261] Alaska, [21,262] West Greenland, [263,264] Northern Sweden (above 608N), Finland (above 608N) and Russia. [262] These lakes gave an overall median modern Hg flux of 11.5 mg m À2 year À1 (mean AE s.d., 20.3 AE 22.3 mg m À2 year À1 ; geometric mean ¼ 12.7 mg m À2 year À1 ).…”

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

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The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

124

147

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Environmental context. Mercury, in its methylated form, is a neurotoxin that biomagnifies in marine and terrestrial foodwebs leading to elevated levels in fish and fish-eating mammals worldwide, including at numerous Arctic locations. Elevated mercury concentrations in Arctic country foods present a significant exposure risk to Arctic people. We present a detailed review of the fate of mercury in Arctic terrestrial and marine ecosystems, taking into account the extreme seasonality of Arctic ecosystems and the unique processes associated with sea ice and Arctic hydrology.Abstract. This review is the result of a series of multidisciplinary meetings organised by the Arctic Monitoring and Assessment Programme as part of their 2011 Assessment 'Mercury in the Arctic'. This paper presents the state-of-the-art knowledge on the environmental fate of mercury following its entry into the Arctic by oceanic, atmospheric and terrestrial pathways. Our focus is on the movement, transformation and bioaccumulation of Hg in aquatic (marine and fresh water) and terrestrial ecosystems. The processes most relevant to biological Hg uptake and the potential risk associated with Hg exposure in wildlife are emphasised. We present discussions of the chemical transformations of newly deposited or transported Hg in marine, fresh water and terrestrial environments and of the movement of Hg from air, soil and water environmental compartments into food webs. Methylation, a key process controlling the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between ecosystem trophic processes and biologic Hg levels. We examine whether atmospheric mercury depletion events (AMDEs) contribute to increased Hg levels in Arctic biota and provide information on the links between organic carbon and Hg speciation, dynamics and bioavailability. Long-term sequestration of Hg into non-biological archives is also addressed. The review concludes by identifying major knowledge gaps in our understanding, including:(1) the rates of Hg entry into marine and terrestrial ecosystems and the rates of inorganic and MeHg uptake by Arctic microbial and algal communities; (2) the bioavailable fraction of AMDE-related Hg and its rate of accumulation by biota and (3) the fresh water and marine MeHg cycle in the Arctic, especially the marine MeHg cycle.

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Section: Since 1993 Prof Henrik Skov Has Worked As Principal Scientimentioning

confidence: 99%

Section: Since 1993 Prof Henrik Skov Has Worked As Principal Scientimentioning

confidence: 99%

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

Section: Eastern Beaufort Sea Belugamentioning

confidence: 99%

See 2 more Smart Citations

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

124

147

View full text Add to dashboard Cite

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“…We therefore propose to use high precision of Ag isotope ratio analysis by MC-ICP-MS as a novel approach for fingerprinting sources of this element in the environment and for studying a wide variety of chemical and biological processes relating to Ag in nature. Notably, silver isotopic composition in the environment has not been studied in depth compared to other heavy metal pollutants such as Hg [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] . Only recently, Yang et al.…”

Section: Introductionmentioning

confidence: 99%

Accurate and Precise Determination of Silver Isotope Fractionation in Environmental Samples by Multicollector-ICPMS

et al. 2010

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High precision silver isotope ratios in environmental s amples were determined by multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS). Purification of Ag from sample matrices was performed by a two stage tandem column setup with use of anion and cation exchange resin, sequentially. It was found that a 1 % HNO 3 and 3 % HCl was efficient to stabilize Ag in the final purified sample digests prior to MC-ICP-MS determination. Pd at 2 µg g -1 was added to both sample and Ag standard solution as a common doping matrix as well as an internal s tandard for mass bias correction. Mass discrimination and instrument drift were corrected by a combination of internal normalization with Pd and standard-sample-standard bracketing, without assuming identical mass bias for Pd and Ag. NIST SRM 978a (silver isotopic standard reference material) was used for method validation and subjected to column separation and sample preparation processes. A value of -0.003±0.010 ‰ for  107/109 Ag (mean and 2SD, n=4) was obtained, confirming accurate results can be obtained using the proposed method.To the best of o ur knowledge, this is the first report on  107/109 Ag variations in environmental samples. Significant differences in Ag isotope ratios were found among NIST SRM 978a standard, sediment CRM PACS-2, domestic sludge SRM 2781, industrial sludge 2782 and the fish liver CRM DOLT-4. The sediment CRM PACS-2 has very small negative High precision of better than ±0.015 ‰ (2SD, n=4) obtained in real sample matrices makes the present method well suited for monitoring small Ag isotope fractionation in nature.

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Screening‐level risk assessment of methylmercury for non‐anadromous Arctic char (Salvelinus alpinus)

Barst

Drevnick

Muir

et al. 2019

Enviro Toxic and Chemistry

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Non‐anadromous forms of Arctic char (Salvelinus alpinus), those that are restricted to lakes and rivers, typically have higher mercury (Hg) concentrations than anadromous forms, which migrate to and from the sea. Using tissue burden data from the literature and our own analyses, we performed a screening‐level risk assessment of methylmercury (MeHg) for non‐anadromous Arctic char. Our assessment included 1569 fish distributed across 83 sites. Site‐specific mean total Hg concentrations in non‐anadromous Arctic char muscle varied considerably from 0.01 to 1.13 µg/g wet weight, with 21% (17 of 83 sites) meeting or exceeding a threshold‐effect level in fish of 0.33 µg/g wet weight, and 13% (11 of 83 sites) meeting or exceeding a threshold‐effect level in fish of 0.5 µg/g wet weight. Of the sites in exceedance of the 0.33‐µg/g threshold, 7 were located in Greenland and 10 in Canada (Labrador, Nunavut, and Yukon). All but one of these sites were located in interfrost or permafrost biomes. Maximum total Hg concentrations exceeded 0.33 µg/g wet weight at 53% of sites (40 of the 75 sites with available maximum Hg values), and exceeded 0.5 µg/g wet weight at 27% (20 of 75 sites). Collectively, these results indicate that certain populations of non‐anadromous Arctic char located mainly in interfrost and permafrost regions may be at risk for MeHg toxicity. This approach provides a simple statistical assessment of MeHg risk to non‐anadromous Arctic char, and does not indicate actual effects. We highlight the need for studies that evaluate the potential toxic effects of MeHg in non‐anadromous Arctic char, as well as those that aid in the development of a MeHg toxic‐effect threshold specific to this species of fish. Environ Toxicol Chem 2019;38:489–502. © 2018 SETAC

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Spatial Trends and Historical Deposition of Mercury in Eastern and Northern Canada Inferred from Lake Sediment Cores

Cited by 190 publications

References 42 publications

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Accurate and Precise Determination of Silver Isotope Fractionation in Environmental Samples by Multicollector-ICPMS

Screening‐level risk assessment of methylmercury for non‐anadromous Arctic char (Salvelinus alpinus)

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