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Outbreak of Minamata Disease
In 1908, Chisso Corporation's factory began producing chemical fertilizers, later becoming a major chemical factory in Japan. The development of the factory was paralleled by the development of the city of Minamata. Minamata, which was just a village, increased its population, becoming an industrial city, and the public of Minamata began working at the Chisso factory. -
Minamata Disease Started
When acetaldehyde is produced, methyl mercury with severe toxicity is generated. The methyl mercury flowed into the sea with discharged water, and sludge containing a large amount of mercury accumulated at the bottom of the sea. However by 1950 shellfish started to die as well as fish with their bellies up, and seaweed stopped growing. -
Discovered The disease
In 1956, it was confirmed for the first time that a disease of unknown cause was affecting people. Because the cause was unknown, doctors did not know what treatment to use at the hospitals. The patients were sterilized or isolated because it was mistaken for a contagious disease. -
Later During the Disease
Later, the theory of organic mercury was researched, and in 1963 a research group from Kumamoto University released its findings that organic mercury was detected from factory discharged water -
Finally Recognized
In 1968, Minamata disease was finally recognized by the government as a pollution disease caused by methylmercury discharged from the Chisso Minamata Factory. -
Water Popallutaion
The methylmercury mixed in the factory discharged water and flown into the sea was absorbed by plankton and got into the bodies of small fish eating the plankton. Smaller fish passed it on to larger fish, finally ending up in people who ate these fish. -
Mnamata Syompthus
Symptoms of Minamata disease include numbness in the limbs, difficulty in moving the hands and legs, a narrowed visual field, language disorders, difficulty in hearing, disorders of the sense of equilibrium, hand and leg tremors, and movement disorders of the eyeballs, etc. In severe cases, people could become mad or unconscious, leading to death. Even in mild cases, symptoms such as headache, fatigue, and difficulty in tasting and smelling, etc. occur, bringing about obstacles in daily life.
