The Minamata disaster, caused by mercury pollution from the Chisso Corporation's chemical factory in Japan, led to severe health effects, including Minamata disease, characterized by neurological symptoms and congenital conditions. Despite initial investigations identifying mercury as the cause, Chisso resisted cooperation and delayed compensation, resulting in prolonged suffering and social stigma for affected communities. Regulatory measures were eventually established, including the Water Pollution Control Law, aimed at preventing similar environmental catastrophes in the future.

1. MINAMATA
DISASTER
B.T.SIDHAARTH
2013111118

2. Outline
• The History(1908-1955)
• 1956-1959
– Finding the cause/Identification of Mercury
• 1959
– Compensation/waste water treatment
• “Ten years of Silence”
– Continued pollution
– Congenital Minamata Disease
• Mercury Poisoning and Control Response
• Measures against Minamata Pollution
– The Water Pollution Control Law
– Restoration of the Environment
– Environmental Impact on Minamata Pollution

3. The History(1908-1955)

4. The History(1908-1955)
• The Chisso Corporation opened a chemical factory in Minamata in
1908.
• Minamata is a city located Kumamoto prefecture, Japan.
• Chisso chemical factory initially produced fertilizers.
• Following the nationwide expansion of Japan’s chemical industry, the
company branched out into the production of acetylene, acetaldehyde,
acetiv acid, vinyl chloride and octanol.
• The Minamata factory became the most advanced in all of Japan.

5. The History(1908-1955)
•The rapid expansion of the Minamata factory spurred on the local
economy.
•Chisso prosperred, so did Minamata.
•Chisso had great influence on Minamata.
•In 1932, Chisso Minamata factory first started acetaldehyde production.
–Producing 210 tons per year.
•By 1951, production had jumped to 6000 tons per year.
–Over half of japan’s total output.

6. The History(1908-1955)
• The chemical reaction used to produce the acetadehyde used
mercury sulphate as catalyst.
• A side reaction of the catalytic cycle led to the production of methyl
mercury.
• Methyl mercury is an organic mercury compound.
• Methyl mercury is a highly toxic component.
• Waste water from Chisso factory were released into Minamata Bay.

7. 1956 - 1959

8. 1956 - 1959
• April 21, 1956, a five year old girl was examined at Chisso’s factory
hospital in Minamata.
• Physicians were puzzled by her symptoms:
– Difficulty in walking, speaking and convulsions.
• Few days later, eight years old girl in the neighbourhood was found
experiencing the similar problrms.
• On May 1, 1956, discovery of an “epidemic of unknown disease of
the central nervous system” was reported to the local public health.
• Patients were isolated – leading to stigmatization and discrimination.

9. 1956 - 1959
• Cats were also seen to have convulsions,
go mad and die.
– This disease in cats were commonly called
as dancing cat fever.
• Crows fell from the sky.
• Fishes floated dead on the sea shore.
• The Kumamoto University Research Group
was formed.
• The disease developed without prior
warning.
• Patients lost sensation, and complained of
numbness in hands and feet.
• By October, 1956, 40 patients were
discovered(14 dead).

10. 1956 - 1959
• The researchers figured the following:
• Staple food of the victims were fish and shellfish from Minamata
Bay.
• Food poisoning by heavy metals.
• Initially, manganese was thought to be the cause substance.
• British neurologist Douglas McAlpine suggested the Minamata
symptoms resembled to those of organic mercury.
• Focus of investigation shifted and centered mercury.

11. 1956 - 1959
• In February, 1959, mercury distribution in Minamata Bay was
investigated.
• Large quantities of mercury detected in fishes from the bay.
• The highest concentration centered around the factory wastewater
canal in Hyakken harbour.

12. 1956 - 1959
• Hair samples of victims and Minamata residents were taken for test.
• The maximum mercury level recorded was 705 ppm.
• This compared to to an average level of 4 ppm for non – minamata
residents.

13. 1959

14. 1959
• Chisso came under close scrutiny.
• In order to deflect criticism, wastewater route was changed.
• It discharged waste water directly into Minamata river.
• Now victims began to appear in other fishing villages up and down
the coast of the Shirauni Sea.

15. 1959
• Chisso did not co-operate with the Kumamoto Research Team.
• Withheld information on its industrial processes.
• Chisso factory’s hospital director, Hajime Hosokawa carried out his
own experiment on Minamata disease.
• He confirmed that it was organic mercury poisoning.
• The company did not reveal the result to the investigators.
• The company orederd Hosokawa to stop the research.

16. 1959
• Compensation for fishermen and patients.
• The agreements were formulated outside the legal system by ad-
hoc mediation committees.
• Final agreements were weighed in favor of Chisso.
• Punitive clauses in the agreements include:
“Representative groups of fishermen and Minamata disease
patients could not make future claims for compensation against the
company”.

17. 1959
WASTEWATER TREATMENT SYSTEM
• On October, 21, Chisso was ordered to switch back its wastewater
drainage to Hyakken Harbour.
• Installed a cyclator purification system with a special ceremony.
• Chisso’s president drank a glass of water supposedly treated to
demonstrate it was safe.
• But wastewater from acetaldehyde plant still contained mercury.
• Deception that company’s wastewater has been made safe.
• In people’s, the issue of Minamata disease was resolved…

18. 1959 – 1969
Ten years of silence

19. 1959 - 1969
• The period between the first set of agreements in 1959 to the first
legal action taken against Chisso in 1969 are is called as the “Ten
years of silence”
• By late 1960, the Kumamoto and Kagoshima perfectural
government continued a joint survey in the hairs of the people living
around the Shiranui sea.
• Results showed that organic mercury had spread all around the
inland sea.

20. 1959 - 1969
CONTINUED POLLUTION
• Contaminated fish still poisoned people.
• 50 ppm of mercury in people’s hair were discovered.
• Highest recorded level was 920 ppm
• The perfectural government did not publish the results, nor did
anything in response to the survey.
• A follow-up study ten years later discovered that many had died
from “unknown causes”

21. 1959 - 1969
CONGENITAL MINAMATA DISEASE
• Local doctors noticed for a long time
an abnormal high frequency of
cerebral palsy.
• A re-examination of children
diagnosed with cerebral palsy was
carried out.
• The symptoms of the children
closely mirrored those of adult
Minamata disease patients.
• However, many of their mothers did
not exhibit symptoms.
• After several years of study and
autopsy of two children, the doctors
diagnosed an unrecognized
congenital form of Minamata
disease.

22. 1959 - 1969
OFFICIAL GOVERNMENT RECOGNITION
• On 26 September 1968, the government finally issued an official
conclusion as to the cause of Minamata disease.
“Minam ata dise ase is a dise ase o f the ce ntralne rvo us syste m , a
po iso ning cause d by lo ng -te rm co nsum ptio n, in larg e am o unts, o f fish and
she llfish fro m Minam ata Bay. The causative ag e nt is m e thylm e rcury.
Me thylm e rcury pro duce d in the ace talde hyde ace tic acid facility o f Shin
Niho n Chisso 's Minam ata facto ry was discharg e d in facto ry waste wate r. . .
Minam ata dise ase patie nts last appe are d in 1 9 6 0 , and the o utbre ak has
e nde d. This is pre sum e d to be be cause co nsum ptio n o f fish and she llfish
fro m Minam ata Bay was banne d in the fallo f 1 9 57 , and the fact that the
facto ry had waste -tre atm e nt facilitie s in place fro m January 1 9 6 0 . "

23. Mercury poisoning

24. Mercury poisoning
• Methyl mercury compound, a inorganic compound which is highly
toxic.
• It is a bi-product during the production of mercury sulphate.

25. Mercury cycle

26. Mercury poisoning
Methylmercury is absorbed 100% into the system through the
intestines with oral intake.

27. Mercury poisoning
SYMPTOMS OF MINAMATA DISEASE
GENERAL
• Muscle weakness
• Damage to hearing, vision and speech
• Crippling hands and feet
EXTREME CASES
• Paralysis
• Coma
• Death

28. Measures against
Minamata pollution

29. Measures against Minamata Pollution
• Temporal variations in acetaldehyde production.
• Final shut down of pollutant sources, by total circulation system
adopted in 1966.

30. Measures against Minamata Pollution
Effluent Control
• Drainage of the Chisso’s factory effluent (containing methylmercury)
to Minamata Bay got regulated.
• In 1970, “Water Pollution Control Law” was enacted.
• The law enforced control of discharge of effluent in all water areas in
Japan, in relation to toxic substances.
• Conversion of production method was advised against caustic soda
plants that might discharge mercury.

31. Measures against Minamata Pollution
The Water Pollution Control Law
The objective of the law is to:
• Prevent pollution of water in the public water areas.
• Regulate effluent discharge by factories into public water areas.
• Protect human health and preserve the living environment.
• Protect sufferers, by incorporating provisions for compensation for
damages.

32. Measures against Minamata Pollution
Restoration of the Environment
• Bottom Sludge treatment
program.
• Reclamation and dredging.
• Mercury concentration reduced to
4.69 ppm.

33. Summary

34. Summary
Root cause Assessment of Minamata Pollution
• Indiscriminate dumping of wastewater.
• Absence of wastewater treatment facility.
• Economic clout of Chisso Corporation.
• Government apathy about the severity of the disease.

35. Summary
Environmental Impact of Minamata Pollution
• Huge quantities of Mercury detected in fish and shellfish in
Minamata Bay.
• Ecology of the Minamata Bay was severely affected.
• Dredging and reclamation done to remove toxic sludge from the
Minamata Bay.

36. Summary
Economic Impact of Minamata Pollution
• Drastic drop in fishing sales, causing loss of livelihood.
• Joblessness leading to high poverty rate.
• Compensation leaves Chisso Corporation in huge debt.

37. Summary
Social Impact of Minamata pollution
• Stigmatization and discrimination against patients.
• Negative image – “The city of Pollution”
• Riot and social unrest.
• Social awareness about the disease.

38. Minamata Photo
Gallery

39. In Japanese, “Chisso” means nitrogen.
Pouring its wastes into the air as well as waters, the
Chisso chemical complex dominates the city of
Minamata.

40. Waste chemicals dumped into the bay, worked their
way up the food chain to the people of the city and
caused the Minamata Disease.

41. Here, fishing on the bay of Minamata. This scene
has changed very little over the centuries. However,
the pollution has changed the relationship that the
people of Minamata had with the sea and fishes.

42. Chisso’s president Shimada, performed Japanese
ritual of shame and apology by touching his
forehead on the ground.

43. Signing of agreement between Patients’ association
and Chisso

44. People demonstrate with photos of the dead on the
last day of the trial in October of 1972

45. References
• Fumikazu Yoshida (2006) “Environmental restoration of Minamata:
New thinking brings new advances”. Integrated research system for
Sustainability Science and Springer, 2:85 – 93.
• Ministry of the Environment, Government of Japan
http://www.env.go.jp/en/
• SOSHISHA, The Supporting Centre For Minamata Disease
http://soshisha.org/english/index_e.htm
• http://en.wikipedia.org/wiki/Minamata_disease

46. Thank You