Health Damages

In Minamata City, Japan Carbide & Co., which was succeeded by the Nippon Chisso Hiryo (Chisso Corporation), established its Minamata Factory in 1908. Since then wastewater, with residue of carbide, was discharged into the coastal water, which caused water pollution. By 1955, fish were observed floating on the sea surface in Minamata Bay, and even the local cats and pigs began to show signs of health problems any many died. In 1956, the hospitalization of a patient with brain damage from an unknown cause was reported to the Minamata Public Health Center in Kumamoto Prefecture. From this, Minamata disease was officially identified. Minamata disease is caused by the ingestion of fish and shellfish from accumulates in humans (and animals) when the fish are eaten. Mercury damages the nervous system. Minamata disease is well known worldwide because of its tragic nature. It took a long time to ascertain the cause of this disease. Patients were discriminated against due to the suspicion that they infected with an epidemic disease. Persons engaged in small-scale local fishery were suddenly out of work due to Minamata disease. Minamata disease caused not only physical pain to its victims, but also mental and economic disaster to them and their families. This led to serious social problems. Lack of appropriate attention to environmental protection by another chemical company caused another occurrence of Minamata disease along the Agano River about 1965.

Water of Jinzu River containing metals such as cadmium, lead and zinc flowed into rice paddy fields since the Taisho era. This caused damage to local agriculture. Patients with strange symptoms began to appear in this area about 1955. They suffered from severe pain, and even small body movement led to bone fractures. They cried “itai-itai, or ouch-ouch” in the midst of intolerable pain, and this disease was called “Itai-itai disease”. The Itai-itai disease was reported to the medical academy in 1955, and was followed by intensive research. In 1968, it was officially announced that cadmium contained in wastewater from the mineral mining company upstream was the cause of this disease.

< back