Haritima : The Environmental Society Of Hansraj College

Minimata Disease


Since the 1960s, Japan has been working on developing an environmental conservation system, and there are now a variety of environmental conservation measures available. However, because the previous time was characterised by rapid economic growth, different sorts of pollution-related damages, including harm to human health, were produced by productive activities that did not pay adequate attention to the environment.

Minamata Disease is a classic example of pollution-related devastation in Japan, in which the environment was devastated, human health was harmed, and the community was heavily influenced as a result of the chemical plant’s drainage. On the other hand, the importance of pollution problems became widely recognised in Japan as a result of the occurrence of Minamata Disease, and pollution measures developed dramatically as a result. As a result, it was the opportunity for the environmental conservation measures that we have today to develop.


In 1956, in Minamata City located on the Yatsushiro Sea coast in Kumamoto Prefecture, the first Minamata Disease patient was reported as a patient suffering from neurological symptoms of unknown cause. Following the initial patient’s disclosure, Minamata City formed the Committee on Unknown Disease to take prompt action against the patients and investigate the reason. The inquiry was primarily carried out by Kumamoto University, which announced in November 1956 that the ailment is a sort of heavy metal poisoning transmitted through fish and shellfish. However, because knowledge and experience concerning environmental pollution were lacking at the time, as was equipment for analysing very minute amounts of chemical substances, it took a long time to figure out what was causing the problem. By the end of March 2001, 2,265 people on the Yatsushiro Sea coast and 690 people in the Agano River basin had been certified as Minamata Disease patients, thanks to the relief mechanism outlined subsequently. Even today, only a few people have been certified, but they all developed the sickness in the past, and according to several investigations, no conditions exist for a new occurrence of Minamata Disease since the early 1970s.


Minamata Condition is a poisoning disease in which methylmercury damages the nervous system, particularly the central nervous system. It has been shown that the sickness is distinct from inorganic mercury poisoning, which destroys kidneys and other organs, and that it does not harm organs other than the nervous system.

Sensory disturbance in the distal portions of the four extremities, cerebellar ataxia, bilateral concentric contraction of the visual field, disturbed ocular movement caused by the central nervous system (CNS), hearing impairment caused by the CNS, and equilibrium disturbance caused by the CNS are among the main signs and symptoms. Also documented is foetal Minamata Disease, which exhibits symptoms similar to cerebral infantile paralysis and is caused by the mother’s exposure to methylmercury during pregnancy.

There were patients who had all of the key signs and symptoms during the early stages of the Minamata Disease outbreak, and some cases resulted in death. Many patients, on the other hand, do not shave all of their primary signs and symptoms at the same time.


  • Closing down of the pollutant sources : In the case of Chisso Co., Ltd.’s Minamata plant, water effluent containing methylmercury compound had not been discharged outside of the plant in principle since the completion of the perfect circulation system in 1966, and the pollutant source had been eliminated since the cessation of acetaldehyde production in 1968. Before Minamata Disease was found, the process of manufacturing acetaldehyde in the Agano River watershed had already shut down.
  • Effluent control : The factory wastewater containing methylmercury was regutted to Minamata Bay in 1969. The Water Pollution Control Law was enacted in 1970, requiring the control of effluent discharge in all water regions in Japan in respect to harmful compounds such as mercury and cadmium. Furthermore, other than Chisso and Showa Denko facilities, conversion of the production process was suggested against caustic soda plants that might dump mercury.

Restoration of the environment : Because methylmercury remained a significant concentration in bottom sediment of related water areas even after the discharge of the methylmercury compound was stopped, Kumamoto Prefecture carried out a project from 1974 to 1990 to deal with about 1,500,000 cubic metres of bottom sediment of Minamata Bay that contained mercury in excess of the remo (of this total, the responsible company bore 30.5 billion yen).


Toxic substances pollute the environment, causing major consequences such as health problems and the degradation of the living environment.

In the instance of Minamata Disease, an agreement was reached between patient organisations and companies, and lawsuits were settled through a compromise between plaintiffs and companies, as well as the withdrawal of plaintiffs between the nation and plaintiffs, resulting in less social problems. However, in the places where the sickness occurred, certified patients are still experiencing symptoms, and the reality is that residents’ health fears have not yet been alleviated.

From the Minamata Disease, Japan has learned that activities that prioritise economic interests while ignoring environmental concerns cause a variety of serious consequences, including health problems, and that it is difficult to recover from these consequences later. From an economic sense, it is evident that these actions are not an economical decision because the steps to mitigate these damages require a significant amount of money and time in compared to the cost of taking measures to prevent pollution from occurring.

With the devastating effects of pollution, especially the Minamata Disease concerns, as a turning point, environmental protection measures in Japan have made significant progress, but the sacrifices made along the way have been enormous. We hope that it will be recognised once more how essential environmental consideration is, and that efforts will be taken to prevent environmental pollution without a devastating pollution experience, using Japan’s experience as a lesson in other nations.

error: Content is protected !!