Minamata disease (水俣病) is a neurological syndrome which affected in in the central
nervous system. It is a form of poisoning caused by severe mercury assembled in human’s
body.
The symptoms of Minamata Disease 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 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 (チッソ) 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
didn’t take immediate measures to rescue local victims and prevent the pollution.