| Title: | Geochemical Factors Controlling Dissolved Elemental Mercury and Methylmercury Formation in Alaskan Wetlands of Varying Trophic Status |
| Author(s): | Poulin BA; Ryan JN; Tate MT; Krabbenhoft DP; Hines ME; Barkay T; Schaefer J; Aiken GR; |
| Address: | "U.S. Geological Survey , Boulder , Colorado 80303 , United States. Department of Civil, Environmental, and Architectural Engineering , University of Colorado Boulder , Boulder , Colorado 80309 , United States. U.S. Geological Survey , Middleton , Wisconsin 53562 , United States. Department of Biological Sciences , University of Massachusetts Lowell , Lowell , Massachusetts 01854 , United States. Department of Biochemistry and Microbiology , Rutgers University , New Brunswick , New Jersey 08901 , United States. Department of Environmental Sciences , Rutgers University , New Brunswick , New Jersey 08901 , United States" |
| ISSN/ISBN: | 1520-5851 (Electronic) 0013-936X (Linking) |
| Abstract: | "The transformations of aqueous inorganic divalent mercury (Hg(II)(i)) to volatile dissolved gaseous mercury (Hg(0)((aq))) and toxic methylmercury (MeHg) govern mercury bioavailability and fate in northern ecosystems. This study quantified concentrations of aqueous mercury species (Hg(II)(i), Hg(0)((aq)), MeHg) and relevant geochemical constituents in pore waters of eight Alaskan wetlands that differ in trophic status (i.e., bog-to-fen gradient) to gain insight on processes controlling dark Hg(II)(i) reduction and Hg(II)(i) methylation. Regardless of wetland trophic status, positive correlations were observed between pore water Hg(II)(i) and dissolved organic carbon (DOC) concentrations. The concentration ratio of Hg(0)((aq)) to Hg(II)(i) exhibited an inverse relationship to Hg(II)(i) concentration. A ubiquitous pathway for Hg(0)((aq)) formation was not identified based on geochemical data, but we surmise that dissolved organic matter (DOM) influences mercury retention in wetland pore waters by complexing Hg(II)(i) and decreasing the concentration of volatile Hg(0)((aq)) relative to Hg(II)(i). There was no evidence of Hg(0)((aq)) abundance directly limiting mercury methylation. The concentration of MeHg relative to Hg(II)(i) was greatest in wetlands of intermediate trophic status, and geochemical data suggest mercury methylation pathways vary between wetlands. Our insights on geochemical factors influencing aqueous mercury speciation should be considered in context of the long-term fate of mercury in northern wetlands" |
| Keywords: | "Ecosystem *Mercury *Methylmercury Compounds *Water Pollutants, Chemical Wetlands;" |
| Notes: | "MedlinePoulin, Brett A Ryan, Joseph N Tate, Michael T Krabbenhoft, David P Hines, Mark E Barkay, Tamar Schaefer, Jeffra Aiken, George R eng Research Support, Non-U.S. Gov't 2019/05/16 Environ Sci Technol. 2019 Jun 4; 53(11):6203-6213. doi: 10.1021/acs.est.8b06041. Epub 2019 May 15" |
