Minamata Outbreak

Minamata disease is a disease of the nervous system that is caused by consuming a large amount of seafood such as fish and shellfish that were contaminated with methylmercury compounds.

On the 1st of May 1956, the patient zero was a 5 years old girl who suffered from unusual neurological symptoms that showed speech disorders and loss of balance so that she could not walk. The following patients were her sister and 4 of her neighbors and the disease was later referred as the minamata disease or the chisso-minamata disease. A massive number of researches lead up into finding a variety of symptoms depending on the exposure level of the chemical. In relatively mild cases the symptoms were barely discernible from other illnesses such as headaches, fatigue, failure of memory, insomnia and could not distinguish taste and smell. While in severe cases, the complaints are conditioned as Hunter-Russell syndrome which characterized by paresthesia, cerebellar ataxia (difficulty in coordinating movement), impaired speech and vision, tremors as well as sensory disturbances in the distal portions of extremities ( disorders of the special sense). As for newborn babies, they may get cerebral palsy if the mercury proceeds to enter to the fetus.

In 1968, the government recognized where the pollution came from and the Chisso Chemical Company took the blame, for the sole reason the Minamata epidemic occurred is because the company discharged a vast amount of acetaldehyde waste, methylmercury into the Yatsushiro sea. Originally, the drainage channel was the waste outfall of Minamata Bay which suited well for discharging but due to the high demand of raw material of octanol, the production of acetaldehyde increase and so the drainage change into the mouth of Minamata river that goes straight into Yatsushiro sea which the company thought was fine. The estimated number of waste that was disposed was around 400 thousand to 1.2 million pounds. But much to their dismay, the toxic contained in the waste did not get eliminated by dilution of the amount of seawater and that's where the methylmercury poisoning came in. The sea creatures such as fish and shellfish absorbed the methylmercury through their gills and when the people who lived nearby consumed the seafood, they got contaminated by the methylmercury compound. The outbreak of the disease expanded along the Yatsushiro coast.

There were a total of 2265 victims including 1178 in Minamata prefecture and 490 in Kagoshima prefecture, thus 900 of the diseased died. The victims and fishermen who signed reconciliation with Chisso received their compensation. Years after the incident, the officials have found ways of preventing the Minamata disease such as recommending women who had mercury levels of 50 ppm or higher to use contraception to prevent fatalities and reducing one's consumption of fish caught from bodies of water that are contaminated with high concentration of mercury. But there was no fundamental cure for those who are already poisoned, so the temporary relief treatments for mild cases are through rehabilitation such as physiotherapy and medication, whereas the severe cases are too complicated to be cured since the nerve cells cannot be regenerated once it dies.

To reminisce and disseminate about the tragedy as a warning to future generations, the town of Minamata established the Minamata Disease Municipal Museum and built Minamata Memorial as a place for a moment of silence for the victims and as a prayer so there would be no repetition of such tragedies and disasters in the future.