Atmospheric mercury concentrations: measurements and profiles near snow and ice surfaces in the Canadian Arctic during Alert 2000

Steffen, Alexandra; Schroeder, W. H.; Bottenheim, J. W.; Narayan, J.; Fuentes, José D.

doi:10.1016/s1352-2310(02)00112-7

Cited by 141 publications

(139 citation statements)

References 12 publications

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“…When the concentration of GEM in ambient air decreased below 1.5 ng sm À3 , the GEM concentration in pyrolyzed air exceeded those measured in the ambient air indicating there are measurable quantities of other mercury species present, which can account for 50% or more of the depleted mercury. It is postulated that the remaining Hg (II) has been lost from the atmosphere by deposition to the snowpack [Lu et al, 2001;Steffen et al, 2002]. The similarity in GEM concentrations seen in Figure 9 at the surface at Alert and at altitudes up to 1 km, together with the vertical mixing suggested by the profiles of Figure 5b indicates that it is possible that 50% of the mercury depletion seen can be accounted for by Hg(II) present in the air but not detected.…”

Section: Processes Influencing the Concentration Of Gem In The Arcticmentioning

confidence: 88%

“…Figure 5b indicates an almost linear relationship on average between GEM and altitude up to 1 km, suggesting that vertical mixing processes in the atmosphere are playing a role in the redistribution of undepleted air from aloft and mercurydepleted air from the surface. While the mechanism by which the depletion of GEM is occurring is currently the subject of research [Lindberg et al, 2000;Steffen et al, 2002], some aspects of the depletion are discussed below.…”

Section: Winter and Spring 1997-1998mentioning

confidence: 99%

“…Measurements were made at the surface at Alert between March and May, 1998 with an Arctic Pyrolysis Unit to provide further insight into the depletion of GEM for the time period of the aircraft study. The operation of this unit, which converts reactive gaseous and particulate forms of mercury to GEM, is described by Steffen et al [2002]. Figure 13 shows results obtained between April 10 and April 20, 1998.…”

Section: Processes Influencing the Concentration Of Gem In The Arcticmentioning

confidence: 99%

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Vertical distribution of gaseous elemental mercury in Canada

Banic¹,

Beauchamp²,

Tordon³

et al. 2003

J. Geophys. Res.

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[1] Measurements of gaseous elemental mercury (GEM) were made in three locations in Canada at altitudes from 0.1 to 7 km. In the summer in southeastern Canada, northwesterly winds bring air with a constant mixing ratio of GEM at altitudes up to 7 km, with a concentration near 1.5 nanograms per standard cubic meter of air (ng sm À3 ). In the winter in southern and central Ontario the mixing ratio is still approximately constant with altitude, but the concentration is 1.7 ng sm À3 . In the spring in the Arctic the concentration of gaseous elemental mercury at altitudes above 1 km is near 1.7 ng sm À3 ; however, there is evidence of episodic depletion of elemental mercury near the surface with mixing of depleted air to altitudes of 1 km. Measurements of GEM in cloud interstitial air and of mercury in cloud water indicate that the influence of a single cycling of air through cloud has little effect on the concentration of GEM. The GEM in air masses transported over the relatively unpopulated terrain of northern Canada during the summer indicates a lower limit of 5000 ng m À2 for an atmospheric column from the surface to 5 km. This gives a global burden of at least 2500 t for that altitude range. These data demonstrate the existence of a vast pool of mercury aloft, provide evidence for a long atmospheric lifetime, and illustrate the potential for long-range atmospheric transport of this metal at altitudes up to at least 7 km.

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Section: Processes Influencing the Concentration Of Gem In The Arcticmentioning

confidence: 88%

Section: Winter and Spring 1997-1998mentioning

confidence: 99%

Section: Processes Influencing the Concentration Of Gem In The Arcticmentioning

confidence: 99%

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Vertical distribution of gaseous elemental mercury in Canada

Banic¹,

Beauchamp²,

Tordon³

et al. 2003

J. Geophys. Res.

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“…This is generally lower than Hg concentrations in interior Arctic sites reported by Douglas and Sturm (2004) (i.e., Hg diss concen- trations between 0.5 and 1.7 ng L −1 ) and at the low end of concentrations found in Arctic studies along the coastal zone (0.14-820 ng L −1 , for both Hg diss and Hg tot ; Douglas et al, 2005;Douglas and Sturm, 2004;Ferrari et al, 2004Ferrari et al, , 2005Kirk et al, 2006;Nerentorp Mastromonaco et al, 2016;St. Louis et al, 2005;Steffen et al, 2002). The low concentrations we measured result in very small pool sizes of Hg diss stored in the snowpack during wintertime compared to temperate studies (Pearson et al, 2015).…”

Section: Snowbound Mercury In the Interior Arctic Snowpack 331 Spatmentioning

confidence: 66%

“…AMDEs are considered to be initiated by halogens Steffen et al, 2008), such as bromine and chlorine radicals released from sea salt by photochemical processes (Simpson et al, 2007). AMDEs have been mainly observed along the coasts, e.g., at Barrow in Alaska , Alert in Canada (Steffen et al, 2002), Ny-Ålesund in Svalbard , McMurdo in Antarctica , and directly over the sea ice Nerentorp Mastromonaco et al, 2016). The impact of AMDEs at inland sites is reduced with increasing distance from the coast (Douglas and Sturm, 2004;Obrist et al, 2017;Van Dam et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Mercury in the Arctic tundra snowpack: temporal and spatial concentration patterns and trace gas exchanges

Agnan¹,

Douglas²,

Helmig³

et al. 2018

The Cryosphere

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Abstract. In the Arctic, the snowpack forms the major interface between atmospheric and terrestrial cycling of mercury (Hg), a global pollutant. We investigated Hg dynamics in an interior Arctic tundra snowpack in northern Alaska during two winter seasons. Using a snow tower system to monitor Hg trace gas exchange, we observed consistent concentration declines of gaseous elemental Hg (Hg 0 gas ) from the atmosphere to the snowpack to soils. The snowpack itself was unlikely a direct sink for atmospheric Hg 0 gas . In addition, there was no evidence of photochemical reduction of Hg II to Hg 0 gas in the tundra snowpack, with the exception of short periods during late winter in the uppermost snow layer. The patterns in this interior Arctic snowpack thus differ substantially from observations in Arctic coastal and temperate snowpacks. We consistently measured low concentrations of both total and dissolved Hg in snowpack throughout the two seasons. Chemical tracers showed that Hg was mainly associated with local mineral dust and regional marine sea spray inputs. Mass balance calculations show that the snowpack represents a small reservoir of Hg, resulting in low inputs during snowmelt. Taken together, the results from this study suggest that interior Arctic snowpacks are negligible sources of Hg to the Arctic.

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Bromide and chloride distribution across the snow‐sea ice‐ocean interface: A comparative study between an Arctic coastal marine site and an experimental sea ice mesocosm

Tenuta

Wang

2016

JGR Oceans

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During springtime in the Arctic, bromine explosion events occur when high concentrations of reactive bromine species are observed in the boundary layer with the concurrence of ozone depletion events and mercury depletion events. While a variety of substrates including snow, sea ice, frost flowers, and aerosols have been proposed to be the substrate and/or source of bromine activation in the Arctic, recent studies have highlighted the role of snow. Here we report concentration profiles of halides (Br− and Cl−), Na+, and mercury across the snow‐sea ice‐seawater interface at a coastal marine site in the Canadian Arctic Archipelago in March and June 2014, as well as in an experimental sea ice mesocosm in Winnipeg in January and February 2014. The occurrence of bromine activation at the Arctic site in March was indicated by the high mercury concentrations in snowpack. At both the Arctic and mesocosm sites, the molar ratios of Br−/Na+ were nearly constant throughout the sea ice depth, but highly variable in the upper layer of the overlying snowpack, revealing that bromine activation takes place in the sunlit snow instead of sea ice. This is supported by calculations showing that the loss of Br– from the upper layer of the snowpack is large enough to produce the observed concentrations of reactive bromine in the atmospheric boundary layer. However, the upper layer of the Arctic snowpack tends to be generally enriched in Br– due to the net addition of Br–‐containing gases and nonsea‐salt aerosols.

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Atmospheric mercury concentrations: measurements and profiles near snow and ice surfaces in the Canadian Arctic during Alert 2000

Cited by 141 publications

References 12 publications

Vertical distribution of gaseous elemental mercury in Canada

Vertical distribution of gaseous elemental mercury in Canada

Mercury in the Arctic tundra snowpack: temporal and spatial concentration patterns and trace gas exchanges

Bromide and chloride distribution across the snow‐sea ice‐ocean interface: A comparative study between an Arctic coastal marine site and an experimental sea ice mesocosm

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