Hydrochemistry and mercury cycling in a High Arctic watershed

Semkin, R. G.; Mierle, Greg; Neureuther, R.

doi:10.1016/j.scitotenv.2004.12.047

Cited by 56 publications

(73 citation statements)

References 53 publications

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“…Total mercury (THg) concentrations in surface water have been reported in levels ranging from subnanogram to more than 1 nanogram per litre in the North Atlantic Ocean , Arctic Russian estuaries (Coquery et al, 1995b) and a high Arctic watershed (Semkin et al, 2005). Maximum concentrations have been measured around 10 (Loseto et al, 2004b;St.…”

Section: Total Mercury In Water Samplesmentioning

confidence: 99%

“…Pre-concentration of Hg onto gold traps by sparging the sample to release Hg(0) from the solution follows this reduction and the Hg contained in this sample is then detected using CVAFS (Loseto et al, 2004a;Aspmo et al, 2006;Hammerschmidt et al, 2006b). Semkin et al (2005) used hydrogen peroxide for oxidative digestion and both Semkin et al (2005) and Coquery et al (2005) reduced Hg(II) species with sodium borohydride. Detection limits ranging from 0.01 to 0.25 ng/L are reported in the aforementioned papers.…”

Section: Total Mercury In Water Samplesmentioning

confidence: 99%

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A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow

Steffen

Douglas

Amyot³

et al. 2008

Atmos. Chem. Phys.

436

439

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Abstract. It was discovered in 1995 that, during the spring time, unexpectedly low concentrations of gaseous elemental mercury (GEM) occurred in the Arctic air. This was surprising for a pollutant known to have a long residence time in the atmosphere; however conditions appeared to exist in the Arctic that promoted this depletion of mercury (Hg). This phenomenon is termed atmospheric mercury depletion events (AMDEs) and its discovery has revolutionized our understanding of the cycling of Hg in Polar Regions while stimulating a significant amount of research to understand its impact to this fragile ecosystem. Shortly after the discovery was made in Canada, AMDEs were confirmed to occur throughout the Arctic, sub-Artic and Antarctic coasts. It is now known that, through a series of photochemically initiated reactions involving halogens, GEM is converted to a Correspondence to: A. Steffen (alexandra.steffen@ec.gc.ca) more reactive species and is subsequently associated to particles in the air and/or deposited to the polar environment. AMDEs are a means by which Hg is transferred from the atmosphere to the environment that was previously unknown. In this article we review Hg research taken place in Polar Regions pertaining to AMDEs, the methods used to collect Hg in different environmental media, research results of the current understanding of AMDEs from field, laboratory and modeling work, how Hg cycles around the environment after AMDEs, gaps in our current knowledge and the future impacts that AMDEs may have on polar environments. The research presented has shown that while considerable improvements in methodology to measure Hg have been made but the main limitation remains knowing the speciation of Hg in the various media. The processes that drive AMDEs and how they occur are discussed. As well, the role that the snow pack and the sea ice play in the cycling of Hg is presented. It has been found that deposition of Hg from AMDEs occurs at marine coasts and not far inland and that a fraction of the Published by Copernicus Publications on behalf of the European Geosciences Union. deposited Hg does not remain in the same form in the snow. Kinetic studies undertaken have demonstrated that bromine is the major oxidant depleting Hg in the atmosphere. Modeling results demonstrate that there is a significant deposition of Hg to Polar Regions as a result of AMDEs. Models have also shown that Hg is readily transported to the Arctic from source regions, at times during springtime when this environment is actively transforming Hg from the atmosphere to the snow and ice surfaces. The presence of significant amounts of methyl Hg in snow in the Arctic surrounding AMDEs is important because this species is the link between the environment and impacts to wildlife and humans. Further, much work on methylation and demethylation processes has occurred but these processes are not yet fully understood. Recent changes in the climate and sea ice cover in Polar Regions are likely to have strong effects on the cycling of Hg in this envir...

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Section: Total Mercury In Water Samplesmentioning

confidence: 99%

Section: Total Mercury In Water Samplesmentioning

confidence: 99%

A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow

Steffen

Douglas

Amyot³

et al. 2008

Atmos. Chem. Phys.

436

439

View full text Add to dashboard Cite

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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%

“…The snow-associated Hg, which is largely of atmospheric origin, flows in meltwater over soils early in the season when they are largely still frozen, and is eventually transported to lakes. [22] Thus the integration of this atmospheric Hg into ecosystem soils and vegetation may be limited. Erosion of thawed soils during summer, a process that seems to be accelerated by climate change, provides an important source of inorganic Hg to lakes in Alaska [21] and possibly elsewhere in the Arctic.…”

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

confidence: 99%

“…[76] In Amituk Lake in the Canadian High Arctic, snowmelt delivered the most THg during spring in June and early July [22,77] but 59 % of the THg delivered to Amituk Lake during the snowmelt period was directly discharged through lake outflow because of the limited mixing between surface and underlying water. [22] In Arctic regions, melt water concentrations of MeHg and THg were found to be elevated above full-column snowpack values at the onset of snow melt in some locations, [20,[77][78][79] but not all. [28] A summary of meltwater THg concentrations reported by six studies at nine sites across the Canadian and Greenland Arctic revealed a range from 0.3 to 10 ng L À1 with an average of ,3 ng L À1 .…”

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

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.

119

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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Mercury concentrations in landlocked Arctic char (Salvelinus alpinus) from the Canadian Arctic. Part I: Insights from trophic relationships in 18 lakes

Gantner

Power

Iqaluk³

et al. 2010

Enviro Toxic and Chemistry

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Concentrations of mercury (Hg) have increased slowly in landlocked Arctic char over a 10- to 15-year period in the Arctic. Fluxes of Hg to sediments also show increases in most Arctic lakes. Correlation of Hg with trophic level (TL) was used to investigate and compare biomagnification of Hg in food webs from lakes in the Canadian Arctic sampled from 2002 to 2007. Concentrations of Hg (total Hg and methylmercury [MeHg]) in food webs were compared across longitudinal and latitudinal gradients in relation to delta(13)C and delta(15)N in periphyton, zooplankton, benthic invertebrates, and Arctic char of varying size-classes. Trophic magnification factors (TMFs) were calculated for the food web in each lake and related to available physical and chemical characteristics of the lakes. The relative content of MeHg increased with trophic level from 4.3 to 12.2% in periphyton, 41 to 79% in zooplankton, 59 to 72% in insects, and 74 to 100% in juvenile and adult char. The delta(13)C signatures of adult char indicated coupling with benthic invertebrates. Cannibalism among char lengthened the food chain. Biomagnification was confirmed in all 18 lakes, with TMFs ranging from 3.5 +/- 1.1 to 64.3 +/- 0.8. Results indicate that TMFs and food chain length (FCL) are key factors in explaining interlake variability in biomagnification of [Hg] among different lakes.

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Hydrochemistry and mercury cycling in a High Arctic watershed

Cited by 56 publications

References 53 publications

A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow

A synthesis of atmospheric mercury depletion event chemistry in the atmosphere and snow

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

Mercury concentrations in landlocked Arctic char (Salvelinus alpinus) from the Canadian Arctic. Part I: Insights from trophic relationships in 18 lakes

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