Understanding minamata disease and strategies to prevent further environmental contamination by methylmercury

Abstract

Minamata disease is a neurological disorder caused by methylmercury poisoning which originated from the discharge of wastewater containing methylmercury from chemical plants in Japan. Residents in the area who consumed large amounts of fish and other seafoods suffered from the disease. The main symptoms consist of sensory disturbance, ataxia, restriction of visual field and hearing impairment. Various measures have been taken to deal with Minamata disease, including environmental pollution control, treatment for patients, and promotion of research activities. Through the compensation law, 2,952 persons have been certified as Minamata disease patients, and a total of approximately 144 billion yen had been paid in compensation by the responsible companies as of March, 1999. Meanwhile, people who were not certified as patients have filed suits against the Japanese Government and local government challenging the diagnostic criteria. The Japanese Government, patients and their supporters reached an agreement in 1996, and Minamata disease legal issues were finally resolved, 40 years after the outbreak. The Minamata experience has left us with an invaluable understanding of the importance of taking thoroughgoing measures to prevent health damage from environmental pollution.