Gaseous elemental mercury (GEM) emissions from snow surfaces in northern New York.

J Alexander Maxwell,Thomas M Holsen,Sumona Mondal

doi:10.1371/journal.pone.0069342

J Alexander Maxwell, Thomas M Holsen + Show 1 more

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https://doi.org/10.1371/journal.pone.0069342

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Journal: PloS one	Publication Date: Jul 12, 2013
Citations: 29	License type: CC BY 4.0

Affiliation: Clarkson University

Abstract

Snow surface-to-air exchange of gaseous elemental mercury (GEM) was measured using a modified Teflon fluorinated ethylene propylene (FEP) dynamic flux chamber (DFC) in a remote, open site in Potsdam, New York. Sampling was conducted during the winter months of 2011. The inlet and outlet of the DFC were coupled with a Tekran Model 2537A mercury (Hg) vapor analyzer using a Tekran Model 1110 two port synchronized sampler. The surface GEM flux ranged from −4.47 ng m−2 hr−1 to 9.89 ng m−2 hr−1. For most sample periods, daytime GEM flux was strongly correlated with solar radiation. The average nighttime GEM flux was slightly negative and was not well correlated with any of the measured meteorological variables. Preliminary, empirical models were developed to estimate GEM emissions from snow surfaces in northern New York. These models suggest that most, if not all, of the Hg deposited with and to snow is reemitted to the atmosphere.

Highlights

Hg is a potent neurotoxin and regulated by the U.S EPA [1], European Union Restriction of Hazardous Substances Directive (RoHS) [2], and other government agencies worldwide as a hazardous pollutant
Daytime fluxes were strongly correlated with solar radiation (PPMC value = 0.684, p-value = 0.000,0.050) and to a lesser extent temperature and relative humidity (PPMC value = 0.103, p-value = 0.035,0.050 and PPMC value = 20.385, p-value = 0.000,0.050 respectively) (Table 2)
This strong correlation with solar radiation suggests that the daytime Hg emissions from the snow surface are a result of the photoreduction of GOM associated with the snow to Gaseous elemental mercury (GEM)

Summary

Introduction

Hg is a potent neurotoxin and regulated by the U.S EPA [1], European Union Restriction of Hazardous Substances Directive (RoHS) [2], and other government agencies worldwide as a hazardous pollutant. Gaseous elemental mercury (GEM) is emitted into the atmosphere from both natural and anthropogenic sources, and has an atmospheric residence time of 0.5–2 years, allowing it to be transported over great distances [4,5,6]. Anthropogenic sources can emit Hg in the form of gaseous oxidized Hg (GOM) and particulate bound Hg (PBM), which have shorter atmospheric lifetimes on the order of days to weeks [4]. GOM is fairly soluble in water, allowing it to be readily deposited to terrestrial surfaces through wet deposition, including snow [4,5,6]. Deposited Hg has been shown to preferentially revolatilize, depending on the deposition surface, in a process known as prompt recycling [7]

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