The Case for Atmospheric Mercury Contamination in Remote Areas

Abstract

Elevated levels of mercury in aquatic environments remote from industrial sources have been broadly attributed to long-range atmospheric transport and deposition of anthropogenic Hg. Evidence in support of this prevailing scientific viewglobal biogeochemical Hg models, sedimentary archives of historic Hg fluxes, and geographic trends in soil Hghave been challenged as being insuf ficiently rigorous to rule out the alternative explanation that natural geologic sources are the principal contributors of Hg in remote locations. In this review, we examine the weaknesses in interpretation and the choice of information that has been used to argue against atmospheric Hg contamination. Analytical advances in measuring trace levels of environmental Hg have greatly narrowed estimates of natural Hg fluxes, providing a clear measure of the relative magnitude of anthropogenic Hg emissions and deposition. Recent experimental results indicate that diagenetic processes cannot explain the mounting number of lake sediment and peat profiles showing substantial increases in Hg flux during the past century. Geologic sources of Hg may be important in specific localities but cannot explain corresponding geographic trends in soil Hg and industrial emission sources. Despite uncertainties in current understanding, there is a broad and geochemically consistent data base indicating that, over large regions of the globe, human-related Hg emissions have increased relative to natural sources since the onset of the industrial period.

Mercury Cycling in Stream Ecosystems. 1. Water Column Chemistry and Transport

“…We assumed that Hg inputs to all streams were predominantly via wet and dry atmospheric deposition (2). Within each state, one urban basin and one or two nonurban basins were studied.…”

“…Hg contamination in fish is now the most common reason for human-health-related fish-consumption advisories (1). Atmospheric deposition of Hg originating from both natural and anthropogenic sources is the predominant Hg input to most aquatic ecosystems (2). Emissions from coal-fired power plants remain the largest single source of unregulated anthropogenic Hg in the U.S. (3), and federal and state governments are currently considering options to reduce these emissions.…”

Atmospheric mercury monitoring survey in Beijing, China

“…Due to its volatility and chemical stability, elemental mercury emissions can circulate in the atmosphere for 1-2 years, allowing its wide dispersion and long-distance transportation (Lin and Pehkonen, 1999). Atmospheric Chemosphere 48 (2002) [97][98][99][100][101][102][103][104][105][106][107] www.elsevier.com/locate/chemosphere mercury originates from natural and anthropogenic sources (Fitzgerald et al, 1998). Natural sources include volcanoes, natural mercury deposits, and volatilization from the oceans.…”

Mercury affects the phylloplane fungal community of blueberry leaves to a lesser extent than plant age

“…Once Hg enters the atmosphere, it may circulate the globe over the course of its 1-year residence time (Schroeder and Munthe 1998). It is thus considered a global pollutant because it reaches areas remotely located from Hg sources through wet and dry deposition from the atmosphere (Fitzgerald et al 1998; Morel et al 1998; Selin 2009). In terrestrial systems, some of the deposited Hg interacts with vegetation and plants that serve as a sink for atmospheric Hg (Stamenkovic and Gustin 2009).…”