Friday, 13 November 2009
The element mercury is a dangerous pollutant of the environment. Mercury may be transported by air and water throughout the earth. Through accidents throughout the world, the adverse health effects have come to public attention. There are several manufactured uses of mercury. Everyone is exposed to small amounts of mercury. Although mercury can occur naturally from the erosion of mineral deposits and volcanoes, human activities will lead to the pollution of the environment. Natural sources contribute two-thirds of the mercury in the environment and one-third were result of human activity. Human activities such as metal smelting, coal production, chemical synthesis and use, and waste deposal will contribute to the pollution. Mercury compounds will transfer between soil, the atmosphere, and surface waters during the cycle of mercury in the environment. The three main forms of mercury that exist in the environment are elemental mercury, inorganic mercury, and organic mercury, which include methylmercury. Each form of mercury has a different solubility, reactivity, biological effects, and toxicity. The toxicity is dependent on the specific compound, route of exposure, dose, and age of the person. Methylmercury is formed by microorganisms from elemental mercury. The main route of exposure to methylmercury is fish consumption. There are significant differences in mercury concentrations in fish species. Methylmercury is demethylated to Hg2+ within tissues. Adults may be less sensitive than children may be to mercury exposure. Sediment, fish tissue, and water systems are all affected by mercury pollution. Consumption advisories are based on consumption patterns and contaminant levels for lakes and rivers.
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