 and Chemistry
The chemical form of mercury affects its emissions, atmospheric transport, and fate. Elemental mercury is relatively unreactive and only sparingly soluble in water, so it is difficult to capture in emission control devices and once emitted can be transported to remote regions of the world. Oxidized forms of mercury, such as mercuric chloride, are quite soluble, more easily captured before emission, and more easily removed from the air by precipitation. The first of Battelle’s studies involves testing instruments that continuously monitor the chemical forms of mercury in combustion flue gas. These mercury continuous emission monitors (CEMs) were tested under Battelle’s Advanced Monitoring Systems Center, part of the U.S. Environmental Protection Agency's (EPA) Environmental Technology Verification (ETV) Program. In that effort, conducted in collaboration with the EPA and the Massachusetts Department of Environmental Protection, four commercial mercury CEMs were tested with diverse flue gas compositions and mercury levels at an EPA pilot-scale incinerator in Research Triangle Park, N.C. Ten performance parameters were evaluated. Battelle’s other program, carried out with the support and collaboration of the Florida Department of Environmental Protection and the EPA, will explore chemical reactions that interconvert the chemical forms of atmospheric mercury. These reactions are important to understand because the form of mercury in the atmosphere can have a major influence on its lifetime and the location of its deposition. Battelle will use a 17m3 environmental chamber and a host of sophisticated measurement tools to study reactions of potential importance to mercury’s atmospheric persistence and fate. The results from these experiments will improve our understanding of atmospheric mercury transformations and may be used as input in models of the atmospheric mercury cycle. For information about the mercury chemical kinetics studies, contact Chet Spicer at (614) 424-5319, spicerc@battelle.org. 
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Mercury is one of the most widely distributed environmental pollutants and one of the most difficult to control. It is released into the air from both man-made sources such as incinerators and natural sources, including the oceans, soils, vegetation, and volcanoes. Battelle is conducting two distinct programs addressing mercury emissions and chemistry. The studies will allow better mercury monitoring technology and improved understanding of the atmospheric mercury cycle. 
As a result of its chemistry, oxidized mercury tends to be deposited relatively near its emission source, whereas elemental mercury is transported globally. Once deposited back to earth, mercury may undergo chemical conversion to form highly toxic methyl mercury, which accumulates through the food chain. Human exposure results through consumption of contaminated fish. 
Performance reports will be available on the ETV Web site, 