The were a group of man-made
disease
A disease is a particular abnormal condition that negatively affects the structure or function of all or part of an organism, and that is not immediately due to any external injury. Diseases are often known to be medical conditions that a ...
s all caused by
environmental pollution
Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, th ...
due to improper handling of
industrial wastes by
Japanese
corporation
A corporation is an organization—usually a group of people or a company—authorized by the state to act as a single entity (a legal entity recognized by private and public law "born out of statute"; a legal person in legal context) and ...
s.
The first occurred in 1912, and the other three occurred in the 1950s and 1960s.
Despite the moniker of 'four' becoming the prominent way to refer to the events,
Minamata disease
Minamata disease is a neurological disease caused by severe mercury poisoning. Signs and symptoms include ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In extrem ...
and
Niigata Minamata disease
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 ...
were the same pollution disease spread by the same poison, just in different locations.
Due to
lawsuits,
publicity, and other actions against the corporations responsible for the pollution, as well as the creation of the
Environmental Agency in 1971, increased public awareness, and changes in industrial practices, the incidence of these kinds of diseases declined after the 1970s. These cases also set precedents for private
tort law
A tort is a civil wrong that causes a claimant to suffer loss or harm, resulting in legal liability for the person who commits the tortious act. Tort law can be contrasted with criminal law, which deals with criminal wrongs that are punishabl ...
and
civil law in issues of compensation for technology-related mass damage which continue to have repercussions in legal cases in Japan today.
Itai-itai disease
Itai-itai disease first occurred in 1912 within
Toyama Prefecture
is a prefecture of Japan located in the Chūbu region of Honshu. Toyama Prefecture has a population of 1,044,588 (1 June 2019) and has a geographic area of 4,247.61 km2 (1,640.01 sq mi). Toyama Prefecture borders Ishikawa Prefecture to the ...
. This disease was given the name "itai-itai" because this was the phrase affected people would frequently cry out; it translates into "it-hurts it-hurts disease".
Cause of itai-itai
The cause of itai-itai disease was determined to be
cadmium poisoning
Cadmium is a naturally occurring toxic metal with common exposure in industrial workplaces, plant soils, and from smoking. Due to its low permissible exposure in humans, overexposure may occur even in situations where trace quantities of cadmium ...
in the
drinking water
Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
from the
Jinzū River
The is a river that flows from Gifu Prefecture to Toyama Prefecture in Japan. It is called Miya River (宮川 ''Miya-gawa'') in Gifu. It is in length and has a watershed of .
Geography
The river flows from Mount Kaore in Gifu and meets the Tak ...
basin. The source of cadmium was discovered to be from
Mitsui Mining and Smelting Company. Mitsui Mining began to discharge cadmium into the Jinzū River in 1910. The cadmium poisoned the river, thus poisoning locals' source of water. Any person who drank that water or ate food that was grown with the contaminated water, such as rice, would be likely to show signs of itai-itai disease.
Symptoms of itai-itai
The first symptoms were spine and leg pain. However, as the disease progresses symptoms include:
*debilitating
pain
*
bone fractures
A bone fracture (abbreviated FRX or Fx, Fx, or #) is a medical condition in which there is a partial or complete break in the continuity of any bone in the body. In more severe cases, the bone may be broken into several fragments, known as a '' ...
from mild traumas or activities (e.g., coughing or walking)
*skeletal deformities
*
anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
*
kidney disorders
The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; bloo ...
Aftermath of itai-itai
Most people with itai-itai disease were confined to bed because walking caused severe pain. Residents of the surrounding area that were harmed by this disease filed a lawsuit against Mitsui Mining & Smelting Company in 1968. Residents won this lawsuit and began to conduct negotiations. Mitsui Mining formally admitted that itai-itai disease was caused by their discharge of cadmium into the Jinzū River. Mitsui Mining was also obliged to pay recovery costs for the land. This meant that they had to ensure the poisoned land was returned to a safe and cultivable state.
Minamata disease
The first report of
Minamata disease
Minamata disease is a neurological disease caused by severe mercury poisoning. Signs and symptoms include ataxia, numbness in the hands and feet, general muscle weakness, loss of peripheral vision, and damage to hearing and speech. In extrem ...
originated in
Minamata in
Kumamoto Prefecture
is a prefecture of Japan located on the island of Kyūshū. Kumamoto Prefecture has a population of 1,748,134 () and has a geographic area of . Kumamoto Prefecture borders Fukuoka Prefecture to the north, Ōita Prefecture to the northeast, M ...
in the year 1956. Many of the earliest patients became insane from the symptoms and in some cases died within a month of being affected. After an extensive investigation, the Minamata disease was identified as a heavy metal poisoning, specifically
methylmercury poisoning, transmitted by the ingestion of contaminated fish from
Minamata Bay. The
methylmercury inside the contaminated fish attacked the affected patient's
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...
, which caused a variety of symptoms.
Symptoms of Minamata disease
*numbing in the arms and legs
*impairment of balance
*fatigue
*
ringing in the ears
*
tunnel vision
Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.
Causes
Tunnel vision can be caused by:
Eyeglass users
Eyeglass users experience tunnel vision t ...
*
loss of hearing
*decrease in communication skills (slurred speech)
Most patients exhibited combinations of symptoms and did not show all symptoms.
Chisso Corporation
The cause of this contamination in Minamata bay was then traced back to
Chisso Corporation
The , since 2012 reorganized as JNC (Japan New Chisso), is a Japanese chemical company. It is an important supplier of liquid crystal used for LCDs, but is best known for its role in the 34-year-long pollution of the water supply in Minamata, Ja ...
's dumping of
methylmercury into Minamata Bay. Chisso Corporation produced
acetaldehyde using
water
Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
,
acetylene,
mercury(II) sulfate
Mercury(II) sulfate, commonly called mercuric sulfate, is the chemical compound Hg S O4. It is an odorless solid that forms white granules or crystalline powder. In water, it separates into an insoluble sulfate with a yellow color and sulfuric a ...
as a catalyst and
manganese dioxide or since August 1951,
ferric sulfide as a co-catalyst.
Acetaldehyde reacts with
acetic anhydride in order to produce
ethylidene diacetate
Ethylidene diacetate is an organic compound with the formula (CH3CO2)2CHCH3. A colorless low-melting solid, it once served as a precursor to vinyl acetate.
Preparation
A major industrial route involves the reaction of acetaldehyde and acetic anhy ...
, which is heated to produce
vinyl acetate
Vinyl acetate is an organic compound with the formula CH3CO2CH=CH2. This colorless liquid is the precursor to polyvinyl acetate and ethene-vinyl acetate copolymers, important industrial polymers.
Production
The worldwide production capacity of v ...
.
Acetaldehyde was also used to produce
acetic acid by oxidizing acetaldehyde and
vinyl chloride
Vinyl chloride is an organochloride with the formula H2C=CHCl. It is also called vinyl chloride monomer (VCM) or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC ...
,
which is
polymerized
In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are many for ...
to make
PVC; however, the use of ferric sulfide had a downside: methylmercury (or organic mercury) was a by-product in the making of these chemicals due to its use. The methylmercury was then dumped into Minamata Bay as chemical waste. Chisso decided not to stop the use of the mentioned catalysts or the dumping of their byproducts into the bay until 1966. Today, Chisso makes compensation payments to all certified (recognized) patients of Minamata disease. Over 50 hectares of the bay were reclaimed, using the contaminated sludge from the bottom of the bay with a non-contaminated layer of soil on top.
Aftermath of Minamata disease
In 1970, the
Japanese Water Pollution Control Act, which states that all factories are required by law to regulate disposal of dangerous chemicals, was enacted. In 1977, the Japanese government took on the task of cleaning Minamata Bay by vacuuming out 1.5 million cubic metres of methylmercury-contaminated sludge from the bottom of the bay and using them to reclaim over 50 hectares of the bay along with non-contaminated soil on top. Then in 1997, after fourteen years and $359 million, the Governor of Kumamoto Prefecture deemed Minamata Bay safe.
Niigata Minamata disease
In 1965, a number of patients in
Niigata Prefecture
is a prefecture in the Chūbu region of Honshu of Japan. Niigata Prefecture has a population of 2,227,496 (1 July 2019) and is the fifth-largest prefecture of Japan by geographic area at . Niigata Prefecture borders Toyama Prefecture and ...
exhibited signs of Minamata disease. Niigata Minamata was caused by
methylmercury poisoning in the Agano River basin. However, this second outbreak of Minamata disease was discovered early on. The degree of this outbreak was minimal compared to that of the first Minamata disease that took place in
Kumamoto prefecture
is a prefecture of Japan located on the island of Kyūshū. Kumamoto Prefecture has a population of 1,748,134 () and has a geographic area of . Kumamoto Prefecture borders Fukuoka Prefecture to the north, Ōita Prefecture to the northeast, M ...
. Investigation of the cause of the disease was given to the
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 (established in 1922) and in Niigata Higher School (established in 1919). It is one of the largest Jap ...
medical department. There were a number of factors that could be the cause of this outbreak. Along the Agano River basin there were several plants that used mercury in production, agricultural chemicals were widely used in the area, and the last possible cause of the outbreak was said to be the cause of an earthquake that took place a year before the disease was discovered in Niigata.
Symptoms of Niigata Minamata disease
As the name implies, Niigata Minamata disease is similar to Minamata disease; they both share the similar symptoms:
* numbness in the arms and legs
* impairment of balance
* fatigue
* ringing in the ears
* tunnel vision
* loss of hearing
* decrease in communication skills
Showa Denko
In the spring of 1966, the research team determined the most likely cause to the dumping of methylmercury from
Showa Denko
, founded in 1939 by the merger of Nihon Electrical Industries and Showa Fertilizers, both established by a Japanese entrepreneur Nobuteru Mori, is a Japanese chemical company producing chemical products and industrial materials.
SDK's products ...
Corporation factory. Showa Denko was located upstream on the Agano River and, just like the Chisso corporation, produced methylmercury as a by-product and then dumped it into the Agano river. Much like Chisso corporation, Showa Denko declined all charges that they were at fault for the Niigata Minamata outbreak.
Aftermath of Niigata Minamata disease
After much controversy, Showa Denko was found guilty of negligence and was then forced to pay compensation payments to all those affected by Niigata Minamata disease. In the year that Niigata Minamata was discovered, 26 people were designated disease patients, and five died as a result of the methylmercury poisoning.
Yokkaichi asthma
Yokkaichi
is a city located in Mie Prefecture, Japan. , the city had an estimated population of 310,259 in 142162 households and a population density of 1500 persons per km². The total area of the city is .
Geography
Yokkaichi is located in north-centra ...
is a city in the center of Japan in
Mie Prefecture
is a prefecture of Japan located in the Kansai region of Honshu. Mie Prefecture has a population of 1,781,948 () and has a geographic area of . Mie Prefecture is bordered by Gifu Prefecture to the north, Shiga Prefecture and Kyoto Prefectur ...
; known as the "town of petroleum" as it produces almost a quarter of the total petroleum in Japan. Construction of the first
oil refinery
An oil refinery or petroleum refinery is an industrial process plant where petroleum (crude oil) is transformed and refined into useful products such as gasoline (petrol), diesel fuel, asphalt base, fuel oils, heating oil, kerosene, lique ...
in this area first began in 1955 and after construction many respiratory diseases emerged within the city and among neighboring districts.
Cause of Yokkaichi asthma
In the middle of this city was the largest heavy oil-fired
power station
A power station, also referred to as a power plant and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Power stations are generally connected to an electrical grid.
Many ...
and refinery in Japan during this time period. Unfortunately, this refinery was not equipped with machines that could lower
sulfur dioxide emissions before releasing them into the air. In the early 1960s, respiratory diseases began to emerge in the general population of Yokkaichi and even in some neighboring districts. This increase in respiratory problems was then specified as
Yokkaichi asthma. This form of
asthma
Asthma is a long-term inflammatory disease of the airways of the lungs. It is characterized by variable and recurring symptoms, reversible airflow obstruction, and easily triggered bronchospasms. Symptoms include episodes of wheezing, co ...
was prevalent within Yokkaichi—5–10% of inhabitants aged 40 in Yokkaichi were reported to have chronic bronchitis, whereas less than 3% had the same disease in non-polluted areas.
Yokkaichi asthma relief system
To offer support for many of the people affected by disease, a public release system for air pollution was established in 1965. This set forth that all people in the Yokkaichi area who met the following criteria were paid by the program:
#Specific diseases such as bronchial asthma, chronic bronchitis, pulmonary emphysema, and their complications.
#In specific areas where the prevalence of that disease has increased.
#Three years of residence within the specified area.
Today, there are many laws regulating the amount of sulfur dioxide a factory can release into the air. These laws help keep the disaster of Yokkaichi Asthma from happening once again within Japan's borders.
See also
*
Environmental issues in Japan
*
Nitrogen oxide
*
Toroku arsenic disease
*
Yushō disease
was a mass poisoning by polychlorinated biphenyls (PCBs) which occurred in northern Kyūshū, Japan, in 1968. In January 1968, rice bran oil produced by Kanemi Company in Kyushu was contaminated with PCBs and polychlorinated dibenzofurans (PCDF ...
An-naka zinc refinery and cadmium pollution, Japan
References
{{Authority control
Environmental disasters in Japan
Health in Japan
Pollution in Japan
*
Mass poisoning
Water pollution in Japan
Corporate scandals