The document discusses the Minamata mercury pollution incident that occurred in Japan between 1908 and 1959. It summarizes that: 1) A chemical factory began dumping mercury-laced wastewater into Minamata Bay in 1908, poisoning the local fishing community through the food chain over decades. 2) "Minamata disease" was discovered and linked to methylmercury poisoning in 1956 when residents developed neurological symptoms. 3) It took until 1959 to officially identify the factory as the source of pollution and order wastewater treatment, by which time many had died or suffered permanent injury from mercury exposure.

1. Minamata Mercury Pollution
Obianuju Ifesiokwu | Emmanuel Mogbo | Cyril Iyasele | Abena Hagan
November 23, 2010

2. Outline
 The History (1908-1955)
 1956-1959
 Finding the cause / identification of mercury
 1959
 Compensation / waste water treatment
 “Ten years of silence” (1959-1969)
 Continued pollution
 Congenital Minamata disease
 Mercury Poisoning and Control Responses
 Measures against Minamata Pollution
 The Water Pollution Control Law
 Restoration of the Environment
 Socio-Economic / Environmental Impact of 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 in 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, acetic 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 prospered, so did Minamata
 Chisso had great influence in Minamata
 In 1932, Chisso Minamata factory first started
acetaldehyde production
 Producing 210 tons per year
 By 1951, production had jumped to 6,000 tons
per year
 Over half of Japan’s total output

6. The History (1908-1955)
 The chemical reaction used to produce the
acetaldehyde used mercury sulfate as a catalyst
 A side reaction of the catalytic cycle led to production
of methylmercury
 Methylmercury is an organic mercury compound
 Methylmercury is a highly toxic compound
 Wastewater from the 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 walking, speaking and convulsions
 Few days later, eight other girls in the neighborhood were
found experiencing similar problem
 On May 1, 1956, a 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
 Crows fell from the sky
 Fish floated dead on the sea surface
 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 had been discovered, 14 had died

10. 1956-1959
 The researchers figured the following:
 staple food of victims was fish and shellfish from Minamata Bay
 food poisoning by heavy metal
 contaminated fish and shellfish as prime suspect
 Waste water from Chisso factory was suspected as the origin
 Initially, manganese was thought to be the causal substance
 British neurologist Douglas McAlpine suggested the Minamata
symptoms resembled those of organic mercury
 Focus of investigation was shifted and centered
on mercury

11. 1956-1959
 In February 1959, mercury distribution in Minamata Bay was investigated
 Large quantities of mercury detected in fish, shellfish and sludge 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 tests
 The maximum mercury level recorded was 705 ppm
 This compared to an average level of 4 ppm for non-
Minamata residents

13. 1959

14. 1959
 Chisso came under closer scrutiny
 In order to deflect criticism, wastewater route was changed
 It discharged wastewater directly into Minamata River
 Minamata disease victims began to appear in other fishing villages up and down
the coast of the Shiranui 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
experiments into Minamata disease
Food to which factory wastewater had been added was fed to healthy cats
 He confirmed a diagnosis of organic mercury poisoning
 The company did not reveal this significant result to the
investigators
 The company ordered Hosokawa to stop his research

16. 1959
Compensation of fishermen and patients
 Minamata disease compensation agreements of 1959
 The agreements were formulated outside the legal system by
ad-hoc mediation committees
 Final agreements were weighted 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 at the factory
 On December 19, Chisso opened its purification system with a
special ceremony
 Chisso’s president drank a glass of water supposedly treated to
demonstrate it was safe
 But waste water from acetaldehyde plant still contained
mercury
 Deception that the factory’s wastewater had been made safe
was successful
 In people’s mind, the issue of Minamata disease had been
resolved

18. 1959 - 1969
"Ten years of silence"

19. 1959 - 1969
 The years between the first set of agreements in 1959 and the start of the first legal
action to be taken against Chisso in 1969 are often called the “ten years of silence”
 By late 1960, the Kumamoto and Kagoshima prefectural governments continued a joint
survey into the level of mercury in the hairs of 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
 A highest recorded level was 920 ppm
 The prefectural governments 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:
“Minamata disease is a disease of the central nervous system, a poisoning caused by
long-term consumption, in large amounts, of fish and shellfish from Minamata Bay. The
causative agent is methylmercury. Methylmercury produced in the acetaldehyde acetic
acid facility of Shin Nihon Chisso's Minamata factory was discharged in factory
wastewater... Minamata disease patients last appeared in 1960, and the outbreak has
ended. This is presumed to be due to the fact that consumption of fish and shellfish from
Minamata Bay was banned in the fall of 1957, and the fact that the factory had waste-
treatment facilities in place from January 1960."

23. Mercury Poisoning

24. Mercury Poisoning
 Methylmercury compound, inorganic compound consist of methyl and mercury
 It is a highly toxic substance
 It is a by-product produced from mercury sulfate
Figure 1: Acetaldehyde manufacturing process using mercury

26. Mercury Poisoning
Effect of Methylmercury Compound on Human Health
 Methylmercury is absorbed 100% into the system through the intestines
with oral intake
Figure 3: Methyl mercury accumulation and its effect on human body

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
Control measures
 Temporal variations in acetaldehyde production
 Final shut down of pollutant sources, by the total circulation system adopted in
1966
Figure 2: Changes in acetaldehyde production, mercury discharge, and Minamata
disease cases

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 conc. reduced to
4.69ppm

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, shellfish and sludge in
Minamata bay
 Ecology of the Minamata bay area
severely affected
 Dredging and reclamation done to
remove the 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 rates
 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”
 Rioting and social unrest
 Social awareness of the disease

38. Minamata Photo
Gallery

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

40. Waste chemicals, dumped into the bay, worked their way up the food chain to the
people of the city and caused what has come to be known as Minamata Disease

41. Here we see an image of an outwardly healthy mother bathing her fetal-poisoned 16 year old
daughter, Tomoko Uemura, physically crippled since birth due to environmental industrial
mercury poisoning in the local Minamata, Japan, water supply

42. 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 have with the
sea and their mainstay of fish

43. Already lame with Minamata disease, Yae Sato carries fresh fish home
for her family's evening meal

44. The signing of an agreement between patients’ associations and Chisso

45. Plaintiffs demonstrate with photos of their dead on the last day of the trial
in October of 1972

46. An aid mops the brow of Chisso's - then President - Shimada, after he
performed the Japanese ritual of shame and apology: touching his
forehead to the ground, at the close of a grueling day in court

47. 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/
• Hirokatsu, A., P. Grandjean, Y. Takizawa and P. Weihe (1997) " Methylmercury Dose Estimation from Umbilical Cord
Concentrations in Patients with Minamata Disease." Environmental Research, Section A 77 98-103
• Osaka, Eri. (2006) "Reevaluating the role of tort liability system in Japan".
• International Center For Environmental Technology Transfer, Japan
http://www.icett.or.jp/lpca_jp.nsf/499529f1186bd4d4492567ca000d587b?OpenView
• Bondy, S.C., 2005. “Minamata” University of California, Irvine, CA, USA
• Tomiyasu, T., et al.,(2005) “Spatial variations of mercury in sediment of Minamata Bay” Japan
• SOSHISHA, The Supporting Center for Minamata Diesease
http://soshisha.org/english/index_e.htm
• http://en.wikipedia.org/wiki/Minamata_disease
• http://www.waterlink.net/jp/history_jp.htm
• http://www.env.go.jp/en/water/wq/pollution/index.html
• http://www.gec.jp/CTT_DATA/WMON/CHAP_1/html/Wmon_007.html
• http://www.masters-of-photography.com/S/smith/smith.html
• http://www.hamline.edu/personal/amurphy01/es110/eswebsite/ProjectsSpring03/ebarker/Minamata%20Web%20Page.htm

48. Thank You