case study

Topics: Minamata disease, Mercury, Mercury poisoning Pages: 10 (3529 words) Published: December 3, 2013


Minamata disease, sometimes referred to as Chisso-Minamata disease, is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of 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. 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 (point source pollution) 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 over more than 30 years, the government and company did little to prevent the pollution. As of March 2001, 2,265 victims had been officially recognized (1,784 of whom had died) and over 10,000 had received financial compensation from Chisso. By 2004, Chisso Corporation had paid $86 million in compensation, and in the same year was ordered to clean up its contamination. Lawsuits and claims for compensation continue to this day. A second outbreak of Minamata disease occurred in Niigata Prefecture in 1965. Both the original Minamata disease and Niigata Minamata disease are considered two of the Four Big Pollution Diseases of Japan.In this case study we are going to analyse the origin and some solutions to the problem.

ORIGIN OF THE DISEASE :-The Chisso Corporation first opened a chemical factory in Minamata in 1908. Initially producing fertilizers, 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 Japan, both before and after World War II. The waste products resulting from the manufacture of these chemicals were released into Minamata Bay in the factory wastewater. Inevitably, 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. The ChissoMinamata factory first started acetaldehyde production in 1932, producing 210 tons that year. By 1951 production had jumped to 6,000 tons per year: over 50% of Japan's total output. The chemical reaction used to produce the acetaldehyde used mercury sulfate as a catalyst. A side reaction of the catalytic cycle led to the production of a small amount of an organic mercury compound, namely methyl mercury. This highly toxic compound was released into Minamata Bay from the start of production in 1932 until 1968 when this production method was discontinued. On April 21, 1956, a five year-old girl was first affected by this disease.Doctors were unable to identify the diseaseTo investigate the epidemic, the city government and various medical practitioners formed the Strange Disease Countermeasures Committee at the end of May 1956. Owing to the localized nature of the disease, it was suspected to be contagious and as a precaution patients were isolated and their homes disinfected. Unfortunately, this contributed to the stigmatisation and discrimination experienced by Minamata victims from the local community. During its investigations, the committee uncovered surprising anecdotal evidence of the strange behavior of cats and other wildlife in the areas surrounding patients' homes. From around 1950 onwards, cats had been seen...

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