Minamata disease: causes, symptoms, and historical impact

Environmental Science

Minamata Disease

This is a paper on Minamata Disease. There are six references used for this paper.

There are a number of diseases which have had profound affects on people throughout the world. It is important to examine Minameta Disease and determine how it was discovered, its causes, how it was settled, the roles played by the government in settling the event and the things which are still unsettled.

Discovering Minameta Disease

The first case of Minameta Disease was reported in 1956, "in Minamata City located on the Yatsushiro Sea coast in Kumamoto Prefecture, in a patient suffering from neurological symptoms of unknown cause (http://www.env.go.jp/en/topic/minamata2002/ch2.html)." This case led Minameta City to immediately develop the "Committee on Unknown Disease to take measures against the patients and investigate to find the cause. The investigation was conducted mainly by Kumamoto University, and in November 1956, the university reported that the disease is a certain type of heavy metal poisoning transmitted via fish and shellfish. Since knowledge and experience about environmental pollution were not enough at that time and technology for analysis of very small amounts of chemical substances was insufficient, a great deal of time was required until the cause was made clear (http://www.env.go.jp/en/topic/minamata2002/ch2.html)."

In 1965, the Agano River basin in Niigata Prefecture reported its first case of Minamata Disease. The government finished interpreting the data collected and in 1968 announced its viewpoint on the disease. They believed that "Minamata Disease was a poisoning disease of the central nervous system caused by methylmercury compound, which was produced as a by-product in the process of manufacturing acetaldehyde at Chisso Co., Ltd. In Minamata City and Showa Denko Co., Ltd. located upstream of Agano River. It was discharged with the factory effluent and polluted the environment, and then, through the food chain, it was accumulated in fish and shellfish. Consequently Minamata Disease occurred when the inhabitants ate high amounts of these seafoods (http://www.env.go.jp/en/topic/minamata2002/ch2.html)."

Deadly Disease

The disease was first seen in May 1956, however by end of the year the "number of identified patients reached 53, of which 17 had already died (http://www.nimd.go.jp/archives/english/tenji/a_corner.html)." The disorder was officially given the name of Minamata Disease in 1957. Although the first cases in the Agano river basin were noted in May 1965, in just two months time the number of cases reported rose to 26 which included 5 patients whose deaths were due to the disease.

Significant First

The poisoning cases in 1956 and 1965 "with organic mercury poisoning were the first to take place in the world through the food chain transfer of its environmental pollution. The cases of organic mercury poisoning that had been known prior to Minamata Disease occurred as the result of the direct poisoning of those who were engaged in organic-mercury handling occupations or those who took it in accidentally (http://www.einap.org/envdis/Minamata.html)."

Understanding the Disease

Minamata Disease is an "encephalopathy and peripheral neuropathy caused by daily intake of fish and shellfish contaminated by methylmercury. Through gills and gastrointestinal tracts, fishery products such as fish, shrimp, crabs, and shellfish take in methylmercury discharged from chemical plants into rivers and seas. Flesh-eating fish that eat those contaminated fish also accumulate the toxic substance. Thus accumulated methylmercury in sea food intoxicates people who have eaten a lot of such sea food daily (http://www.nimd.go.jp/archives/english/tenji/a_corner.html)."

Mercury Debates

In 1957, cats became intoxicated when they were "fed fish and shellfish from Minamata Bay by Dr. Ito, the Head of the Minamata Public Health Center, and Dr. Takeuchi. Drs. Takeuchi, Tokuomi and Kitamura of Kumamoto University determined the cause of Minamata disease was organic mercury in fish and shell fish from the bay, and reported it on July 22, 1959. They met objections that methylmercury could not be in the bay because inorganic mercury, not organic mercury, was used in the suspected factory (http://www.nimd.go.jp/archives/english/tenji/b_corner.html)."

The doctor's conclusions were proven in November 1961 when methylmercury was found in Minamata Bay shellfish. Further proof was provided in August 1962 when "Dr. Irukayama extracted methylmercury compound from the waste catalyst taken at the acetaldehyde production plant (http://www.nimd.go.jp/archives/english/tenji/b_corner.html)."

Governmental Involvement

In 1968, the issue of Minamata Disease was finally addressed by the "Japanese government (Ministry of Health and Welfare) when it issued an official statement that 'the cause of Minamata Disease was methylmercury produced during the acetaldehyde production process of the Chisso Minamata factory' (http://www1.odn.ne.jp/~aah07310/english/politicsp.html)." Although the government was made aware of the dangers as early as 1963, it did not address the issue until after the factory had been closed when "the production process which used mercury as a catalyst became outmoded, and demand for acetaldehyde was fully met by petroleum technology (http://www1.odn.ne.jp/~aah07310/english/politicsp.html)." The Japanese government in effect put the needs of the factory above the well-being of its citizens and environment.

It wasn't until February 1969 that the area was "designated a protected marine area by the government, thereby requiring that no wastewater containing methylmercury be released into it, well after the polluting production process had been shut down (http://www1.odn.ne.jp/~aah07310/english/politicsp.html)."

Political Settlements

There was a settlement plan developed in 1973 known as the "Compensation Agreement, which was based on the Compensation Law. However, there have been administrative and administrative litigation appeals against rejections of the applications for Minamata Disease certification, and there have been damage suits and direct negotiations conducted mainly by those who rejected the certification (http://www.env.go.jp/en/topic/minamata2002/ch5.html)." These issues have not yet been settled.

The final settlement plan was submitted in September, 1995 by "three ruling coalition parties (Liberal Democratic Party, Socialist Party (now, Social Democratic Party) and New Party Sakigake). All the parties concerned declared to accept the settlement by December 1995, and the agreement based on the final plan for settlement by three ruling coalition parties was concluded through direct negotiation between patients' group and Showa Denko Co., Ltd. ()."

In December 1995, the Government took measures to finalize the Minamata Disease settlement by holding a "meeting of the members of the Cabinet concerned for the Minamata Disease, and made the arrangement with 'On the Measures against Minamata Disease', whose content was to resume to accept applications of the Task of Medicine of the Comprehensive Measures for Minamata Disease and to forward and support the measures to recover and promote the region.

On the same day, it made the agreement of the Cabinet meeting about it, etc., and also made the decision of the Cabinet meeting for 'Prime Minister's Announcement for the settlement of Minamata Disease issues', and the Government implemented these measures (http://www.env.go.jp/en/topic/minamata2002/ch5.html)."

Continuing Lawsuit

In May 2001, an appeal was filed in the Supreme Court of Japan by "national and Kumamoto Prefectural governments to the April 27 Osaka Court of Appeals verdict which acknowledged the responsibility for the nation and Kumamoto Prefecture to Minamata disease. On July 7, 2001, the plaintiffs formed the 'National Network Seeking Withdrawal of Governmental Appeal of Minamata Disease Lawsuit and started a nationwide movement seeking withdrawal of the appeal by the national and Kumamoto Prefectural governments (http://www1.odn.ne.jp/~aah07310/english/index-e.html)."