Atmospheric Mercury Concentrations Associated with Geologically and Anthropogenically Enriched Sites in Central Western Nevada

Abstract

This paper documents the atmospheric mercury concentrations above anthropogenically contaminated and naturally enriched sites in central western Nevada. Atmospheric mercury concentrations were measured at five representative regional sites (1.2−7.5 ng/m3) and two anthropogenically contaminated areas (13−866 ng/m3) in the Carson River Superfund Site. The highest regional concentrations were measured at the Steamboat Geothermal area, where mercury mineralization occurs naturally. Concurrent with atmospheric sampling, environmental conditions were monitored to assess their covariance with mercury concentrations. Atmospheric mercury concentrations were influenced by multiple factors with dominance exerted by substrate mercury concentration, site surface characteristics, and local and synoptic scale air masses. A mercury flux of 5−125 (±50%) μg of mercury m-2 h-1 was estimated via modified K-theory for a contaminated location. This flux was scaled up to estimate the contribution of atmospheric mercury from mine wastes within the Carson River Superfund Site. The estimated annual flux (150−400 kg/yr) is comparable to that from a 1000 MW coal-fired power plant (300 kg/yr). The projected longevity of this diffuse source exceeds 104 years, so the cumulative contribution over time from this region far exceeds the corresponding contribution of a coal-fired power plant whose life time is measured in decades.

Atmospheric Mercury Emissions and Speciation at the Sulphur Bank Mercury Mine Superfund Site, Northern California

“…Seigneur et al (44) suggested that reactions with gaseous sulfur species were also possible. The geothermal brines at the SBMM contain high concentrations of SO4, chloride, and bromide (34), and HCl was measured in the air at the site (21). In addition, high emissions of H2S and NH3 have been reported in gases at the site (24).…”

Increases in mercury emissions from desert soils in response to rainfall and irrigation

“…We assumed that meteorological effects are slight inside an enclosed flux chamber and estimated the contribution of the soil gas Hg ø which was displaced by the rain water as follows: It is more likely that the second process listed above has a major contribution. The soil analyses [Gustin, et al, 1996, this issue (a)] show that most of the soil plots contained a large proportion of total Hg as Hg ø, ---30-50%. Since the soil mer---2 cury flux over prerain dry soils was relatively low (---40 ng m h-•), we propose that before the rain, most of the Hg ø in the soils was adsorbed to dry soil particle surfaces and not directly available for emission.…”

“…Mercury exists in soils in several forms, many of which (particularly Hg ø) exhibit relatively high elevated vapor pressures at background temperature. The primary sources of Hg in soils which have not been with temperature, and many studies have reported exponential relationships between temperature and emission rates for background, contaminated, and geologically enriched soils as well as buried wastes [e.g., Lindberg and Turner, 1977;Lindberg et al, 1979;Xiao et al, 1991;Lindberg et al, 1995;Gustin et al, 1996]. Because of the strong temperature effect, few other relationships have been as well documented, and the recent suggestions of a direct effect of solar radiation on fluxes are complicated by indirect temperature effects frdm soil heating [Gustin et al, 1996;Carpi and Lindberg, 1998].…”

A laboratory based experimental study of mercury emission from contaminated soils in the River Idrijca catchment

“…In recent years, considerable progress in understanding mercury geochemistry at such sites has been made with the development of interfacial mercury flux measurement technology (Ferrara et al, 1998a;Ferrara et al, 1998b;Gustin et al, 1996;Nacht et al, 2004;Gustin, 2003;Engle et al, 2001). Mercury emission rates from these Hg-enriched areas were found to be greater than previously estimated, indicating that these sources may be more significant contributors of mercury to the atmosphere than previously realized (Gustin et al, 2000;Gustin, 2003;Engle et al, 2001;Wang et al, 2005, Wang et al, 2007a, Wang et al, 2007bCoolbaugh et al, 2002;Feng et al, 2005).…”