Niigata Minamata disease
Encyclopedia
is a neurological syndrome caused by severe mercury poisoning
. Identical in symptoms to the original outbreak of Minamata disease
in Kumamoto Prefecture
, the second outbreak in Niigata Prefecture
was confirmed with the same name in 1965. The disease was caused by severe mercury poisoning
, the source of which was methylmercury
released in the wastewater
from mercury sulfate
-catalysed acetaldehyde
production at the Showa Electrical Company
's chemical plant in Kanose village
. This highly toxic compound was released untreated into the Agano River
where it bioaccumulated up the food chain, contaminating fish
which when eaten by local people caused symptoms including ataxia
, numbness in the hands and feet, general muscle weakness
, narrowing of the field of vision and damage to hearing and speech.
690 people from the Agano River
basin have been certified as patients of Niigata Minamata disease.
Since the Niigata outbreak was the second recorded in Japan
and occurred in the Lower Agano River
Basin, it is sometimes called or . It is one of the Four Big Pollution Diseases of Japan
.
in Niigata Prefecture
was discovered in a very similar way to the original outbreak in Kumamoto Prefecture
. From the autumn of 1964 to the spring of 1965, cats living along the banks of the Agano River
had been seen to go mad and die: "...one cat ran into a small clay cooking stove containing burning charcoal. With the pupils of its eyes dilated, salivating, convulsing and uttering a strange cry, the cat breathed its last breath". These strange symptoms eventually began to appear in people too. Professor Tadao Tsubaki of Niigata University
examined two patients in April and May 1965 and suspected Minamata disease. One patient's hair was found to have a mercury level of 390 ppm. On 31 May he reported an outbreak of organic
mercury poisoning
in the Agano River
basin to the prefectural government and made his findings public on 12 June.
Research Group (that had been set up to investigate the original outbreak) and Dr. Hajime Hosokawa
(the former Chisso
hospital director) brought their significant experience from Minamata and applied it to the Niigata outbreak. Many lessons were learned from Minamata and the investigation into the cause of the outbreak proceeded much more smoothly than it had in Minamata. The prefectural government, Niigata University, citizen's organisations and local people all worked together to uncover the cause. In March 1966 it was reported that factory plant wastewater
was suspected as the source of pollution and in September the Ministry of Health and Welfare announced that it had discovered methylmercury
in moss
at the outlet of the Showa Denko
factory in Kanose village
.
had responded in Minamata
: by attempting to discredit the researchers while proposing their own theory. The company issued information leaflets that rejected their wastewater as the cause of the disease and suggested that the cause might have been an "agricultural chemical run-off" that entered the river after the 1964 Niigata earthquake
.
On 26 September 1968, the government announced its official conclusion as to the cause of Niigata Minamata disease. The report said that although "the circumstances of the poisoning are extremely complex, and they are difficult to reproduce", the mercury had probably been discharged from the Kanose plant over a long period of time. However the report did not rule out other causes and Showa Denko's president Masao Yasunishi insisted that the company was not the cause of the outbreak.
The Niigata lawsuit was ultimately successful and on 29 September 1971 the court found Showa Denko guilty of negligence. Families of deceased and congenital patients received JPY10 million, surviving patients were awarded between JPY1 million and JPY10 million depending on symptoms, JPY400,000 to those contaminated by mercury and JPY300,000 was awarded to pregnant women who had been told to have abortions due to the danger posed to their unborn children.
A family-member of the deceased patient testified in court, "My father was crazed like a wild beast and then died—agonized, in pain... like a dog."
The events in Niigata catalysed a change in response to the original Minamata incident. The scientific research carried out in Niigata forced a re-examination of that done in Minamata and the decision of Niigata patients to sue the polluting company allowed the same response to be considered in Minamata. Masazumi Harada
has said that "It may sound strange, but if this second Minamata disease had not broken out, the medical and social progress achieved by now in Kumamoto... would have been impossible."
Mercury poisoning
Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...
. Identical in symptoms to the original outbreak of Minamata disease
Minamata disease
', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...
in Kumamoto Prefecture
Kumamoto Prefecture
is a prefecture of Japan located on Kyushu Island. The capital is the city of Kumamoto.- History :Historically the area was called Higo Province; and the province was renamed Kumamoto during the Meiji Restoration. The creation of prefectures was part of the abolition of the feudal system...
, the second outbreak in Niigata Prefecture
Niigata Prefecture
is a prefecture of Japan located on the island of Honshū on the coast of the Sea of Japan. The capital is the city of Niigata. The name "Niigata" literally means "new lagoon".- History :...
was confirmed with the same name in 1965. The disease was caused by severe mercury poisoning
Mercury poisoning
Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...
, the source of which was methylmercury
Methylmercury
Methylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...
released in the wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
from mercury sulfate
Mercury(II) sulfate
Mercury sulfate, commonly called mercuric sulfate is the chemical compound Hg S O4. It is an odorless solid that forms white granules or crystalline powder...
-catalysed acetaldehyde
Acetaldehyde
Acetaldehyde is an organic chemical compound with the formula CH3CHO or MeCHO. It is one of the most important aldehydes, occurring widely in nature and being produced on a large scale industrially. Acetaldehyde occurs naturally in coffee, bread, and ripe fruit, and is produced by plants as part...
production at the Showa Electrical Company
Showa Denko
is a leading Japanese chemical engineering firm.Formed in 1939 by the merger of Nihon Electrical Industries and Showa Fertilizers, Showa Denko K.K. manufactures chemical products and industrial materials. SDK's products serve a wide array of fields ranging from heavy industry to the electronic...
's chemical plant in Kanose village
Kanose, Niigata
was a town located in Higashikanbara District, Niigata, Japan.As of 2003, the town had an estimated population of 2,753 and a density of 10.68 persons per km²...
. This highly toxic compound was released untreated into the Agano River
Agano River
The Agano River is a river which flows from Fukushima Prefecture to Niigata Prefecture in Japan. It is called the Aga River or the Ōkawa River in Fukushima. It is 210km long with 7,710km² watershed....
where it bioaccumulated up the food chain, contaminating fish
Mercury in fish
Fish and shellfish concentrate mercury in their bodies, often in the form of methylmercury, a highly toxic organic compound of mercury. Fish products have been shown to contain varying amounts of heavy metals, particularly mercury and fat-soluble pollutants from water pollution...
which when eaten by local people caused symptoms including ataxia
Ataxia
Ataxia is a neurological sign and symptom that consists of gross lack of coordination of muscle movements. Ataxia is a non-specific clinical manifestation implying dysfunction of the parts of the nervous system that coordinate movement, such as the cerebellum...
, numbness in the hands and feet, general muscle weakness
Muscle weakness
Muscle weakness or myasthenia is a lack of muscle strength. The causes are many and can be divided into conditions that have true or perceived muscle weakness...
, narrowing of the field of vision and damage to hearing and speech.
690 people from the Agano River
Agano River
The Agano River is a river which flows from Fukushima Prefecture to Niigata Prefecture in Japan. It is called the Aga River or the Ōkawa River in Fukushima. It is 210km long with 7,710km² watershed....
basin have been certified as patients of Niigata Minamata disease.
Since the Niigata outbreak was the second recorded in Japan
Japan
Japan is an island nation in East Asia. Located in the Pacific Ocean, it lies to the east of the Sea of Japan, China, North Korea, South Korea and Russia, stretching from the Sea of Okhotsk in the north to the East China Sea and Taiwan in the south...
and occurred in the Lower Agano River
Agano River
The Agano River is a river which flows from Fukushima Prefecture to Niigata Prefecture in Japan. It is called the Aga River or the Ōkawa River in Fukushima. It is 210km long with 7,710km² watershed....
Basin, it is sometimes called or . It is one of the Four Big Pollution Diseases of Japan
Four Big Pollution Diseases of Japan
The were a group of manmade diseases all caused by environmental pollution due to improper handling of industrial wastes by Japanese corporations. Although some cases of these diseases occurred as early as 1912, most occurred in the 1950s, 1960s, and 1970s....
.
Discovery
The second outbreak of Minamata diseaseMinamata disease
', sometimes referred to as , is a neurological syndrome caused by severe mercury poisoning. Symptoms include ataxia, numbness in the hands and feet, general muscle weakness, narrowing of the field of vision and damage to hearing and speech. In extreme cases, insanity, paralysis, coma, and death...
in Niigata Prefecture
Niigata Prefecture
is a prefecture of Japan located on the island of Honshū on the coast of the Sea of Japan. The capital is the city of Niigata. The name "Niigata" literally means "new lagoon".- History :...
was discovered in a very similar way to the original outbreak in Kumamoto Prefecture
Kumamoto Prefecture
is a prefecture of Japan located on Kyushu Island. The capital is the city of Kumamoto.- History :Historically the area was called Higo Province; and the province was renamed Kumamoto during the Meiji Restoration. The creation of prefectures was part of the abolition of the feudal system...
. From the autumn of 1964 to the spring of 1965, cats living along the banks of the Agano River
Agano River
The Agano River is a river which flows from Fukushima Prefecture to Niigata Prefecture in Japan. It is called the Aga River or the Ōkawa River in Fukushima. It is 210km long with 7,710km² watershed....
had been seen to go mad and die: "...one cat ran into a small clay cooking stove containing burning charcoal. With the pupils of its eyes dilated, salivating, convulsing and uttering a strange cry, the cat breathed its last breath". These strange symptoms eventually began to appear in people too. Professor Tadao Tsubaki of Niigata University
Niigata University
is a national university in Niigata, Niigata Prefecture, Japan. It was established in 1949 and has its major origins in Niigata Medical College and in Niigata Higher School . It is one of the largest Japanese national universities on the Sea of Japan.The university comprises nine faculties and...
examined two patients in April and May 1965 and suspected Minamata disease. One patient's hair was found to have a mercury level of 390 ppm. On 31 May he reported an outbreak of organic
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
mercury poisoning
Mercury poisoning
Mercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...
in the Agano River
Agano River
The Agano River is a river which flows from Fukushima Prefecture to Niigata Prefecture in Japan. It is called the Aga River or the Ōkawa River in Fukushima. It is 210km long with 7,710km² watershed....
basin to the prefectural government and made his findings public on 12 June.
Investigation
Throughout 1965 and 1966 researchers from the Kumamoto UniversityKumamoto University
is a university located in Kumamoto, Japan. It was established on May 31, 1949, at which time the following institutions were subsumed into it; Kumamoto Teachers College , Kumamoto Pharmaceutical College , The Fifth High School , Kumamoto Medical College , and Kumamoto Technical College ....
Research Group (that had been set up to investigate the original outbreak) and Dr. Hajime Hosokawa
Hajime Hosokawa
' was director of the company hospital attached to the Chisso corporation's chemical factory in Minamata, Kumamoto prefecture, Japan. He was the first doctor to discover and treat patients of the massive outbreak of mercury poisoning that occurred in the town which became known as Minamata...
(the former Chisso
Chisso
The is a Japanese chemical company. It is particularly well known as a supplier of liquid crystal used for LCD displays.Chisso is also known for its thirty-four year long contamination of the water supply in Minamata, Japan that led to thousands of deaths and victims of disease...
hospital director) brought their significant experience from Minamata and applied it to the Niigata outbreak. Many lessons were learned from Minamata and the investigation into the cause of the outbreak proceeded much more smoothly than it had in Minamata. The prefectural government, Niigata University, citizen's organisations and local people all worked together to uncover the cause. In March 1966 it was reported that factory plant wastewater
Wastewater
Wastewater is any water that has been adversely affected in quality by anthropogenic influence. It comprises liquid waste discharged by domestic residences, commercial properties, industry, and/or agriculture and can encompass a wide range of potential contaminants and concentrations...
was suspected as the source of pollution and in September the Ministry of Health and Welfare announced that it had discovered methylmercury
Methylmercury
Methylmercury is an organometallic cation with the formula . It is a bioaccumulative environmental toxicant.-Structure:...
in moss
Moss
Mosses are small, soft plants that are typically 1–10 cm tall, though some species are much larger. They commonly grow close together in clumps or mats in damp or shady locations. They do not have flowers or seeds, and their simple leaves cover the thin wiry stems...
at the outlet of the Showa Denko
Showa Denko
is a leading Japanese chemical engineering firm.Formed in 1939 by the merger of Nihon Electrical Industries and Showa Fertilizers, Showa Denko K.K. manufactures chemical products and industrial materials. SDK's products serve a wide array of fields ranging from heavy industry to the electronic...
factory in Kanose village
Kanose, Niigata
was a town located in Higashikanbara District, Niigata, Japan.As of 2003, the town had an estimated population of 2,753 and a density of 10.68 persons per km²...
.
Response of Showa Denko
Showa Denko responded to the outbreak of Niigata Minamata Disease in a similar way that ChissoChisso
The is a Japanese chemical company. It is particularly well known as a supplier of liquid crystal used for LCD displays.Chisso is also known for its thirty-four year long contamination of the water supply in Minamata, Japan that led to thousands of deaths and victims of disease...
had responded in Minamata
Minamata, Kumamoto
is a city located in Kumamoto prefecture, Japan. It is on the west coast of Kyūshū. The city was founded on April 1, 1949.As of 2008, the city has an estimated population of 27,856 and the density of 171 persons per km²...
: by attempting to discredit the researchers while proposing their own theory. The company issued information leaflets that rejected their wastewater as the cause of the disease and suggested that the cause might have been an "agricultural chemical run-off" that entered the river after the 1964 Niigata earthquake
1964 Niigata earthquake
The 1964 Niigata earthquake struck at 13:01 local time on 16 June. The epicenter was on the continental shelf off the northwest coast of Honshu in Niigata Prefecture, about 50 km north of the city of Niigata...
.
Patients' lawsuit
Unlike their counterparts in Minamata, the victims of Showa Denko's pollution lived a considerable distance from the factory and had no particular link to the company. As a result the local community was much more supportive of patients' groups and a lawsuit was filed against the company in March 1968. The Niigata lawsuit was filed only three years after the outbreak had been made public in 1965. In contrast the first lawsuit filed in Minamata happened in 1969, thirteen years after the original outbreak was discovered.On 26 September 1968, the government announced its official conclusion as to the cause of Niigata Minamata disease. The report said that although "the circumstances of the poisoning are extremely complex, and they are difficult to reproduce", the mercury had probably been discharged from the Kanose plant over a long period of time. However the report did not rule out other causes and Showa Denko's president Masao Yasunishi insisted that the company was not the cause of the outbreak.
The Niigata lawsuit was ultimately successful and on 29 September 1971 the court found Showa Denko guilty of negligence. Families of deceased and congenital patients received JPY10 million, surviving patients were awarded between JPY1 million and JPY10 million depending on symptoms, JPY400,000 to those contaminated by mercury and JPY300,000 was awarded to pregnant women who had been told to have abortions due to the danger posed to their unborn children.
A family-member of the deceased patient testified in court, "My father was crazed like a wild beast and then died—agonized, in pain... like a dog."
The events in Niigata catalysed a change in response to the original Minamata incident. The scientific research carried out in Niigata forced a re-examination of that done in Minamata and the decision of Niigata patients to sue the polluting company allowed the same response to be considered in Minamata. Masazumi Harada
Masazumi Harada
is a Japanese doctor and medical researcher. His most famous work has been into the effects of Minamata disease, a type of severe mercury poisoning that occurred in the city of Minamata, Kumamoto Prefecture during the 1950s and 1960s...
has said that "It may sound strange, but if this second Minamata disease had not broken out, the medical and social progress achieved by now in Kumamoto... would have been impossible."
See also
- Ontario Minamata diseaseOntario Minamata diseaseOntario Minamata disease is a neurological syndrome caused by severe mercury poisoning. It occurred in the Canadian province of Ontario in 1970 and severely affected two First Nation communities located in Northwestern Ontario following consumption of local fish that were contaminated with mercury...
- Heavy metal poisoningHeavy Metal PoisoningHeavy Metal Poisoning is a song by American rock band Styx. It was included as the fifth track on their 1983 studio album Kilroy Was Here.The song in the story of Kilroy Was Here has the character of Dr Righteous preaching the evils of rock and roll...
- Mercury poisoningMercury poisoningMercury poisoning is a disease caused by exposure to mercury or its compounds. Mercury is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses...
, a disease caused by exposure to the element mercury or its toxic compounds