大気中の水銀に関する研究の現状

概要

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This review presents the conclusions of recent international studies pertaining to the speciation, emission sources, and fate of mercury in the atmosphere. The background level of total gaseous mercury concentration in the air is 1-3 ng m^<-3>. Mercury takes various physical and chemical forms in the atmosphere, mainly gaseous elemental mercury [Hg (0)], gaseous divalent mercury [Hg (II)], particulate mercury [Hg (p)]. Hg (0) is the dominant form of mercury in the atmosphere and the concentrations of Hg (II) and Hg (p) are generally only a few percent of the total concentration of airborne mercury. Because these three species have different characteristics with respect to transport, deposition, and influences on ecosystems, mercury speciation measurements are of great importance. Mercury is emitted from natural and anthropogenic sources. Natural sources include volcanic activity and evasion from sea, soil and vegetation surfaces. Anthropogenic sources include coal combustion, waste incineration, and non-ferrous metal refining and smelting. Mercury emitted from these sources into the atmosphere is removed by wet and dry deposition. Wet deposition is the main process of mercury removal from the atmosphere. In this process, atmospheric oxidation processes in which Hg (0) is converted to Hg (II) by O_3, H_2O_2, and Cl_2 play important roles.
日本地球化学会の論文
2000-06-10