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Environ Sci Technol

Title:		Geochemical controls on the production and distribution of methylmercury in near-shore marine sediments
Author(s):		Hammerschmidt CR; Fitzgerald WF;
Address:		"Department of Marine Sciences, University of Connecticut, Groton, Connecticut 06340, USA. chad.hammerschmidt@uconn.edu"
Journal Title:		Environ Sci Technol
Year:		2004
Volume:		38
Issue:		5
Page Number:		1487 - 1495
DOI:		10.1021/es034528q
ISSN/ISBN:		0013-936X (Print) 0013-936X (Linking)
Abstract:		"We examined temporal differences in sedimentary production of monomethylmercury (MMHg) at three sites in Long Island Sound (LIS). Sediment-phase concentrations of Hg species decreased from west to east in LIS surface sediments, following the trend of organic matter. However, Hg methylation potentials, measured by incubation with an isotopic tracer (200Hg), increased from west to east. 200Hg methylation potentials were enhanced in August relative to March and June, attributable to differences in activity of sulfate-reducing bacteria. Organic matter and acid-volatile sulfide influenced the distribution coefficient (KD) of inorganic Hg (Hg(II) = total Hg - MMHg) and inhibited 200Hg methylation in surface sediments. 200Hg methylation varied inversely with the KD of Hg(II) and positively with the concentration of Hg(II), mostly as HgS0, in LIS pore waters. Accordingly, we posit that a principal control on MMHg production in low-sulfide, coastal marine sediments is partitioning of Hg(II) between particle and dissolved phases, which regulates availability of Hg substrate to methylating bacteria. Most of the partitioning in LIS sediments is due to Hg-organic associations. This suggests that reductions in the organic content of coastal sediment, a potential result of nutrient abatement programs intended to inhibit eutrophication of near-shore waters, could enhance MMHg production by increasing the bioavailability of the large reservoir of 'legacy Hg' buried within the sediment"
Keywords:		Biological Availability *Eutrophication Geologic Sediments/*chemistry Geological Phenomena Geology Mercury/*chemistry/pharmacokinetics Methylmercury Compounds/*analysis/*chemistry New York Particle Size Solubility;
Notes:		"MedlineHammerschmidt, Chad R Fitzgerald, William F eng Research Support, U.S. Gov't, Non-P.H.S. 2004/03/30 Environ Sci Technol. 2004 Mar 1; 38(5):1487-95. doi: 10.1021/es034528q"