Mercury

Mercury is a naturally occurring metal that exists in several physical and chemical forms. Inorganic mercury refers to compounds formed after the combining of mercury with elements such as chlorine, sulfur, or oxygen. After combining with carbon by covalent linkage, the compounds formed are called organic mercury compounds or organomercurials. The most common forms of mercury in the environment are elemental mercury, mercuric sulfide (cinnabar ore, from which elemental mercury is refined by heating), mercuric chloride, and the organic mercury compound methylmercury. In the environment, methylmercury is produced by the methylation of inorganic mercury by microorganisms. This form of mercury may enter and accumulate in the aquatic food chain [1]. Major methylmercury poisonings occurred in Minamata Bay, Japan, in the 1950s after the consumption of contaminated seafood following severe industrial mercury discharge into the bay. Another mass tragedy occurred in Iraq in 1971–1972 after the consumption of bread contaminated with methylmercury used as a fungicide on seed grain [2]