The itai-itai disease (Japanese:イタイイタイ病, literally: ouch-ouch-disease) was the first cadmium poisoning in the world in Toyama prefecture, Japan in 1950. The cadmium poisoning caused softening of the bones and kidney failures. The name of the disease comes from the painful screams (Japanese: 痛い itai) due to the severe pain in the joints and the spine. The cadmium was released in the rivers by mining companies in the mountains. The mining companies were successfully sued for the damage.
The itai-itai disease was caused by cadmium poisoning due to mining in the Toyama prefecture. Earliest records of mining for gold in the area date back to 710. Regular mining for silver started in 1589, and soon thereafter for lead, copper, and zinc. Increase demand of raw material for the Russo-Japanese War and World War I and new mining technologies from Europe increased the output of the mines, putting the Kamioka Mines among the worlds top mines. Production increased even more before World War II. Cadmium was released in significant quantities starting from 1910 to about 1945, and the disease first appeared around 1912. Prior to World War II the mining, controlled by the Mitsui Mining and Smelting Co., Ltd, increased to satisfy the wartime demand. This subsequently increased the pollution of the Jinzu river and the rivers leading into the Jinzu river. The river was used mainly for irrigation of the rice fields, but also drinking, washing, fishing, and other uses by the downstream population.
Due to the cadmium poisoning, the fish in the river started to die, and the rice irrigated with river water did not grow well. The cadmium and other heavy metals accumulated at the bottom of the river and in the water of the river. This water was then used to irrigate the rice fields. The rice absorbed all heavy metals, but especially the cadmium. The cadmium accumulated in the people eating contaminated rice. The population complained to the Mitsui Mining and Smelting company about the pollution, which subsequently built a basin to store the mining waste water before leading it into the river. This, however, was too little too late, and many people already were very sick. The causes of the poisoning were not well understood, and up to 1946 it was thought to be simply a regional disease, or possible a bacteria. Medical test started in the 1940s and 1950s, searching for the cause of the disease. Initially, it was expected to be lead poisoning due to the lead mining upstream. Only in 1955 did Dr. Ogino and his colleagues suspect cadmium as the cause of the disease. Dr. Ogino also coined the term itai-itai disease. The Toyama prefecture also started an investigation in 1961, determining that the Kamioka Mining Station of the Mitsui Mining and Smelting company caused the cadmium pollution, and that the worst affected areas were 30 km downstream of the mine. In 1968 the Ministry of Health and Welfare issued a statement about the symptoms of the itai-itai disease caused by the cadmium poisoning.
The reduction of the levels of cadmium in the water supply reduced the number of new disease victims, and no new victim has been recorded since 1946. However, while the victims with the worst symptoms came from the Toyama prefecture, the government also found victims in five other prefectures. The mines are still in operation today.
There are a number of symptoms associated with cadmium poisoning. The two main organs affected are the bones and the kidneys. The bones get soft (osteomalacia) and lose bone mass and become weaker (Osteoporosis). This causes the pain in the joints and the back, and also increases the risk of fractures. In extreme cases of cadmium poisoning the body weight alone might cause a fracture.
The second affected organ is the kidney, which loses its function to remove acids from the blood, a so called proximal renal tubular dysfunction. The kidney damage due to cadmium poisoning is irreversible and does not heal over time, and the victims of the itai-itai disease still have this disorder. The proximal renal tubular dysfunction creates low phosphate levels in the blood hypophosphatemia, causing muscle weaknesses and coma. The dysfunction also causes Gout, a form of arthritis due to the accumulation of sodium urate crystals in the joints because of high blood levels of uric acid (hyperuricemia). Another side effect are increased levels of chloride in the blood (hyperchloremia). The kidneys can also shrink up to 30%.
The liver will also be affected by cadmium poisoning.
Overall, the disease limited the movement of the victims and caused great pain and sometimes death. Many of the victims were women past their menopause, where the bones have a natural tendency to become brittle, which aggregated the effect of the disease.
29 plaintiffs, consisting of nine victims and 20 family members of the victims sued the Mitsui Mining and Smelting Co. in 1968 at the Toyama prefecture court. In the verdict in June 1971 the court found the Mitsui Mining and Smelting Co. guilty. Subsequently, the company appealed to the Nagoya Supreme Court in Kanazawa, but the appeal was rejected in August 1972. The Mitsui Mining and Smelting Co. agreed to pay for the medical care of the victims, finance the monitoring of the water quality performed by the residents, and paid reparations to the victims of the disease.
People who consider themselves victims of the itai-itai disease have to contact the Japanese ministry of health to have their claims assessed. However, many victims were not satisfied with the government actions, and demanded a change in the official procedures. This caused the government to review the criteria for recognizing a victim legally and also the treatment against the disease. A person is considered to have the itai-itai disease if he or she lived in the contaminated areas, has kidney dysfunctions, softening of the bones, but no related heart problems. 184 victims have been legally recognized since 1967, of which 54 were recognized in the period from 1980 to 2000. However, only 15 victims were still alive in 1993.
In 1992, the average annual health expense compensation was 743 million yen. Agricultural damage was compensated with 1.75 billion yen per year, or a total of annually 2.518 billion yen. Another 620 million yen were invested annually to reduce further pollution of the river.
- Environmental Sciences in Japan (http://ltm.agriculture.purdue.edu/esj/)
- Additional Information on Itai-Itai Disease (http://www.kanazawa-med.ac.jp/~pubhealt/cadmium2/itaiitai-e/itai01.html)
- Preventative Measures Against Water Pollution (http://www.icett.or.jp/lpca_jp.nsf/a21a0d8b94740fbd492567ca000d5879?OpenView)