Mercury cycles

Volatilization is also a dominant transport mode for mercury, which is the most volatile metal in its elemental state. As with lead, a key reaction that can increase the volatility of mercury is formation of an organometallic compound. In this case, the reactions take place in water and are primarily biological, being mediated by bacteria commonly found in the upper levels of sediments. These reactions and their importance in the global mercury cycle are discussed in some detail later in the chapter. 

Fig. 15-8 The mercury cycle, demonstrating the bioaccumulation of mercury in fish and shellfish. Reprinted with permission from An Assessment of Mercury in the Environment" (1978) by the National Academy of Sciences, National Academy Press, Washington, DC.

FIGURE 1.1 Conceptual diagram of mercury cycling and bioaccumulation in the environment. 

Policy makers would benefit from a combination of strong field evidence of trends and well-established models to draw upon when assessing the benefits of past or future policy decisions. Models of mercury cycling and bioaccumulation are not yet adequately predictive across a range of conditions and landscapes. Results from a national mercury monitoring program, if carefully designed, offer the potential to... 

Hudson RJM, Gherini SA, Watras CJ, Porcella DB. 1994. Modeling the biogeochemical cycle of mercury in lakes the Mercury Cycling Model (MCM) and its application to the MTL study lakes. In Watras CJ, Huckabee JW, editors. Mercury pollution integration and synthesis. Boca Raton (FL) Lewis Publishers, CRC Press Inc., p. 473-523. 

Pirrone N, Ferrara R, Hedgecock IM, Kallos G, Mamane Y, Munthe J, Pacyna JM, Pytharoulis I, Sprovieri F, Voudouri A, Wangberg 1.2003b. Dynamic processes of mercury over the Mediterranean region results from the Mediterranean Atmospheric Mercury Cycle System (MAMCS) project. Atmos Environ 37(Sl) 21-39. 

Krabbenhoft DP, Babiarz CL. 1992. The role of groundwater transport in aquatic mercury cycling. Water Resources Res 28 3119-3128. 

Krabbenhoft DP, Beniot JM, Babiarz CL, Hurley JP, Andren AW. 1995. Mercury cycling in the AUequash Creek Watershed Water Air Soil Pollut 80 425M33. 

Fitzgerald WF, Mason RP. 1996. The global mercury cycle oceanic and anthropogenic aspects. In Baeyens W, Ebinghaus R, Vasihev O, editors. Global and regional mercury cycles sources, fluxes and mass balances, Dordrecht, the Netherlands Kluwer Academic Publishers, p. 85-108. 

Zillioux EJ, Porcella DB, Benoit JM. 1993. Mercury cycling and effects in freshwater wetland ecosystems. Environ Toxicol Chem 12 2245-2264. 

Griepink B eds.. Quality Assurance for Environmental Analysis, pp 89-110. Elsevier, Amsterdam. Horvat M (1996) Mercury speciation and analysis. In Global and Regional Mercury Cycles Sources. Fluxes and Mass Balances, Baeyens W, Ebinghaus R and Vasiliev O, eds. pp 1-31. Kluwer Academic Publishers, The Netherlands. 

High body burdens of mercury normally encountered in some species of fish and wildlife from remote locations emphasize the complexity of natural mercury cycles and human impacts on these cycles... 

Allard, B. and I. Arsenie. 1991. Abiotic reduction of mercury by humic substances in aquatic system — an important process for the mercury cycle. Water Air Soil Pollut. 56 457-464. 

Chasar, L.C., Scudder, B.C., Stewart, A.R., Bell, A.H., Aiken, G.R. 2009. Mercury Cycling in Stream Ecosystems. 3. Trophic Dynamics and Methylmercury... 

Meng, F., Arp, P., Sangster, A., Brun, G.I., Rencz, A., Hall, G., Holmes, J., Lean, D., Clair, T. 2005. Modeling dissolved organic carbon, total and methyl mercury in Kejimkujik freshwaters. In Mercury Cycling in a Wetland Dominated Ecosystem A Multidisciplinary Study. Society of Environmental Toxicology and Chemistry, Pensacola, FL, 267-284. 

Natural emission and re-emission processes are particularly important for the mercury cycle in the environment. The distribution of mercury re-emission from soil in Europe is illustrated in Figure 4. The most significant re-emission fluxes are in Central Europe... 

Marine mercury cycle. All fluxes are in units of Mmol/y. Preindustrial fluxes are in parentheses. The marine boundary layer is the iower part of the troposphere in which mercury transformations associated with the air-sea interface occur. Source After Mason, R. R, and G.-R. Sheu (2002). Global Blogeochemical Cycles 16, GB001440. 

The third section focuses on the behavior of trace metals, with an emphasis on processes that control their solubility and transport. It includes a chapter on mercury cycling in softwater lakes and two chapters that examine the solubility and transport of trace metals in two very different environ-... 

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