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, sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death follow within weeks of the onset of symptoms. A congenital form of the disease can also affect fetuses in the womb. Minamata disease was first discovered in Minamata city in Kumamoto prefecture, Japan, in 1956. It was caused by the release of methylmercury in the industrial wastewater from the Chisso Corporation's chemical factory, which continued from 1932 to 1968. This highly toxic chemical bioaccumulated in shellfish and fish in Minamata Bay and the Shiranui Sea, which, when eaten by the local populace, resulted in mercury poisoning. While cat, dog, pig, and human deaths continued for 36 years, the government and company did little to prevent the pollution. The animal effects were severe enough in cats that they came to be named as having "dancing cat fever".〔Stephen J. Withrow, David M. Vail, ''Withrow and MacEwen's Small Animal Clinical Oncology'', Elsevier: 2007, ISBN 0721605583, p. 73-4.〕 As of March 2001, 2,265 victims had been officially recognised as having Minamata disease (1,784 of whom had died)〔Official government figure as of March 2001. See ("Minamata Disease: The History and Measures, ch2" )〕 and over 10,000 had received financial compensation from Chisso.〔See ("Minamata Disease Archives" ), Frequently asked questions, Question 6 〕 By 2004, Chisso Corporation had paid $86 million in compensation, and in the same year was ordered to clean up its contamination.〔Jane Hightower (2008). ''Diagnosis Mercury: Money, Politics and Poison'', Island Press, p. 77.〕 On March 29, 2010, a settlement was reached to compensate as-yet uncertified victims.〔("Agreement reached to settle Minamata suit" ), ''Asahi Shimbun'' news, 31 March 2010, retrieved 1 April 2010〕 A second outbreak of Minamata disease occurred in Niigata Prefecture in 1965. The original Minamata disease and Niigata Minamata disease are considered two of the four big pollution diseases of Japan. == 1908–1955 == The Chisso Corporation first opened a chemical factory in Minamata in 1908. Initially producing fertilisers, the factory followed the nationwide expansion of Japan's chemical industry, branching out into production of acetylene, acetaldehyde, acetic acid, vinyl chloride, and octanol, among others. The Minamata factory became the most advanced in all of Japan, both before and after World War II. The waste products resulting from the manufacture of these chemicals were released into Minamata Bay through the factory wastewater. These pollutants had an environmental impact. Fisheries were damaged in terms of reduced catches, and in response, Chisso reached two separate compensation agreements with the fishery cooperative in 1926 and 1943.〔Harada, p15〕 The rapid expansion of the Minamata factory spurred on the local economy and as Chisso prospered, so did Minamata. This fact, combined with the lack of other industry, meant that Chisso had great influence in Minamata. At one point, over half of the tax revenue of Minamata City authority came from Chisso and its employees, and the company and its subsidiaries were responsible for creating a quarter of all jobs in Minamata.〔George, pp35-36〕 Minamata was even dubbed Chisso's "castle town", in reference to the capital cities of feudal lords who ruled Japan during the Edo period.〔George, p26〕 The Chisso Minamata factory first started acetaldehyde production in 1932, producing 210 tons that year. By 1951, production had jumped to 6,000 tons per year and reached a peak of 45,245 tons in 1960.〔Report of the Social Scientific Study Group on Minamata Disease, ''(In the Hope of Avoiding Repetition of a Tragedy of Minamata Disease )'', National Institute for Minamata Disease, p. 13.〕 Throughout, the Chisso factory's output amounted to between a quarter and a third of Japan's total acetaldehyde production. The chemical reaction used to produce the acetaldehyde used mercury sulfate as a catalyst. Starting August 1951, the co-catalyst was changed from manganese dioxide to ferric sulfide.〔Eto et al. (2010)〕 A side reaction of this catalytic cycle led to the production of a small amount of an organic mercury compound, namely methylmercury.〔For further information on the chemistry of the reaction that lead to the production of methylmercury see ("Information on Mercury" ) by Mercury Technology Services, retrieved around the 24 October 2006〕 This highly toxic compound was released into Minamata Bay from the change of the co-catalyst in 1951 until 1968, when this production method was discontinued.〔Gilhooly, Rob, "(Mercury rising: Niigata struggles to bury its Minamata ghosts )", ''Japan Times'', 13 June 2015〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Minamata disease」の詳細全文を読む スポンサード リンク
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