Mercury transformations and fluxes in sediments of a riverine wetland

Goulet, Richard R.; Holmes, Jonathan A.; Page, Bryan; Poissant, Laurier; Siciliano, Steven D.; Lean, D. R. S.; Wang, Fei; Amyot, Marc; Tessier, André

doi:10.1016/j.gca.2007.04.032

Cited by 58 publications

(49 citation statements)

References 66 publications

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“…It is difficult to compare these MeHg consumption rate values directly with published rates because MeHg consumption likely includes both demethylation and sorption, Goulet et al (2007) reported net demethylation rates ranging from 0.4 to 12.4 3 10 221 mol cm 23 s 21 . In most of their porewater MeHg profiles, however, net MeHg production was observed at the SWI.…”

Section: Resultsmentioning

confidence: 99%

“…PROFILE models of pore-water dynamics assume the absence of a significant advective flux and that the system is, at least, at quasi-steady state (i.e., LC Lt < 0). Although steady-state assumptions may not be strictly valid for environments subject to variations in salinity, bottomwater dissolved O 2 , or temperature, diagenetic models such as PROFILE have allowed exploration of the depthspecific parameters that facilitate either sequestration or mobilization of sediment contaminants (Gallon et al 2004;Goulet et al 2007;Merritt and Amirbahman 2007).…”

Section: Methodsmentioning

confidence: 99%

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Methylmercury cycling in estuarine sediment pore waters (Penobscot River estuary, Maine, USA)

Merritt

Amirbahman

2008

Limnology & Oceanography

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Methylmercury cycling in estuarine sediment pore waters (Penobscot River estuary, Maine, USA)

Merritt

Amirbahman

2008

Limnology & Oceanography

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“…A fraction of the mercury that is deposited onto snowpacks is revolatilized rapidly (Lalonde et al, 2002). The fraction of mercury retained by snowpacks may be transported by the snowpack meltwater runoff to aquatic environments such as oceans, freshwater wetlands and peatlands where methylation can occur (Loseto et al, 2004;Goulet et al, 2007;Mitchell et al, 2008a;Sunderland et al, 2009). Since methylmercury is a potent bioaccumulating neuro-toxin and since a high proportion of the Aboriginal peoples' diet in Arctic countries consists of country foods that include large marine mammals and fish (Van Oostdam et al, 2005), the fate of mercury deposited onto snowpacks is an issue of great concern.…”

Section: Introductionmentioning

confidence: 99%

How relevant is the deposition of mercury onto snowpacks? – Part 2: A modeling study

Durnford¹,

Dastoor

Ryzhkov

et al. 2012

Atmos. Chem. Phys.

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Abstract. An unknown fraction of mercury that is deposited onto snowpacks is revolatilized to the atmosphere. Determining the revolatilized fraction is important since mercury that enters the snowpack meltwater may be converted to highly toxic bioaccumulating methylmercury. In this study, we present a new dynamic physically-based snowpack/meltwater model for mercury that is suitable for large-scale atmospheric models for mercury. It represents the primary physical and chemical processes that determine the fate of mercury deposited onto snowpacks. The snowpack/meltwater model was implemented in Environment Canada's atmospheric mercury model GRAHM. For the first time, observed snowpack-related mercury concentrations are used to evaluate and constrain an atmospheric mercury model. We find that simulated concentrations of mercury in both snowpacks and the atmosphere's surface layer agree closely with observations. The simulated concentration of mercury in both in the top 30 cm and the top 150 cm of the snowpack, averaged over 2005-2009, is predominantly below 6 ng L −1 over land south of 66.5°N but exceeds 18 ng L −1 over sea ice in extensive areas of the Arctic Ocean and Hudson Bay. The average simulated concentration of mercury in snowpack meltwater runoff tends to be higher on the Russian/European side (>20 ng L −1 ) of the Arctic Ocean than on the Canadian side (<10 ng L −1 ). The correlation coefficient between observed and simulated monthly mean atmospheric surface-level gaseous elemental mercury (GEM) concentrations increased significantly with the inclusion of the new snowpack/meltwater model at two of the three stations (midlatitude, subarctic) studied and remained constant at the third (arctic). Oceanic emissions are postulated to produce the observed summertime maximum in concentrations of surface-level atmospheric GEM at Alert in the Canadian Arctic and to generate the summertime volatility observed in these concentrations at both Alert and Kuujjuarapik on subarctic Hudson Bay, Canada. We find that the fraction of deposited mercury that is revolatilized from snowpacks increases with latitude from 39 % between 30 and 45°N, to 57 % from 45 to 60°N, 67 % from 60 to 66.5°N, and 75 % polewards of 66.5°N on an annual basis. Combining this latitudinal gradient with the latitudinally increasing coverage of snowpacks causes yearly net deposition as a fraction of gross deposition to decrease from 98 % between 30 and 45°N to 89 % between 45 and 60°N, 73 % between 60 and 66.5°N, and 44 % within the Arctic Circle. The yearly net deposition and net accumulation of mercury at the surface within the Arctic Circle north of 66.5°N are estimated at 153 and 117 Mg, respectively. We calculate that 58 and 50 Mg of mercury are deposited annually to the Arctic Ocean directly and indirectly via melting snowpacks, respectively. For terrestrial surfaces within the Arctic Circle, we find that 29 and 16 Mg of mercury are deposited annually directly and indirectly via melting snowpacks, respectively. Within the Arctic Circle, multi-s...

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“…Once deposited, mercury can be converted to highly toxic bioaccumulating methylmercury. Methylation can occur in aqueous environments such as oceans (Sunderland et al 2009), freshwater wetlands (Loseto et al 2004;Goulet et al 2007) and peatlands (Mitchell et al 2008). It is speculated that factors affected by climate change, such as earlier ice breakup, increased snowmelt and warmer temperatures, may influence these conversion processes and, thus, the overall input of Hg to the Arctic environment and the bioaccumulation in wildlife and humans.…”

Section: Atmospheric Transport and Behaviour Of Toxic Pollutants In Tmentioning

confidence: 99%

Selected topics in arctic atmosphere and climate

et al. 2012

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This paper summarizes the main elements of four IPYprojects that examine the Arctic Atmosphere. All four projects focus on present conditions with a view to anticipating possible climate change. All four investigate the Arctic atmosphere, ocean, ice, and land interfacial surfaces. One project uses computer models to simulate the dynamics of the Arctic atmosphere, storms, and their interactions with the ocean and ice interface. Another project uses statistical methods to infer transports of pollutants as simulated in large-scale global atmospheric and oceanic models verifying results with available observations. A third project focuses on measurements of pollutants at the ice-ocean-atmosphere interface, with reference to model estimates. The fourth project is concerned with multiple, high accuracy measurements at Eureka in the Canadian Archipelago. While these projects are distinctly different, led by different teams and interdisciplinary collaborators, with different technical approaches and methodologies, and differing objectives, they all strive to understand the processes of the Arctic atmosphere and climate, and to lay the basis for projections of future changes. Key findings include:• Decreased sea ice leads to more intense storms, higher winds, reduced surface albedo, increased surface air temperature, and enhanced vertical mixing in the upper ocean. • Arctic warming may affect toxic chemicals by remobilizing persistent organic pollutants and augmenting mercury deposition/retention in the environment.• Changes in sea ice can dramatically change processes in and at the ice surface related to ozone, mercury and bromine oxide and related chemical/physical properties.• Structure and properties of the Arctic atmospheric-troposphere to stratosphere-and tracking of transport of pollution and smoke plumes from mid-latitudes to the poles.

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Mercury transformations and fluxes in sediments of a riverine wetland

Cited by 58 publications

References 66 publications

Methylmercury cycling in estuarine sediment pore waters (Penobscot River estuary, Maine, USA)

Methylmercury cycling in estuarine sediment pore waters (Penobscot River estuary, Maine, USA)

How relevant is the deposition of mercury onto snowpacks? – Part 2: A modeling study

Selected topics in arctic atmosphere and climate

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