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was the name given to the mass cadmium poisoning of Toyama Prefecture, Japan, starting around 1912. The term "''itai-itai'' disease" was coined by locals〔ICETT Itai-itai disease (1998) http://www.icett.or.jp/lpca_jp.nsf/a21a0d8b94740fbd492567ca000d5879/b30e2e489f4b4ff1492567ca0011ff90?OpenDocument〕 for the severe pains (Japanese: 痛い ''itai'') victims felt in the spine and joints. Cadmium poisoning can also cause softening of the bones and kidney failure. The cadmium was released into rivers by mining companies in the mountains, which were successfully sued for the damage. Itai-itai disease is known as one of the Four Big Pollution Diseases of Japan. ==Cause== Itai-itai disease was caused by cadmium poisoning due to mining in Toyama Prefecture. The earliest records of mining for gold in the area date back to 1710. Regular mining for silver started in 1589, and soon thereafter, mining for lead, copper, and zinc began. Increased demand for raw materials during the Russo-Japanese War and World War I, as well as new mining technologies from Europe, increased the output of the mines, putting the Kamioka Mines in Toyama among the world's top mines. Production increased even more before World War II. Starting in 1910 and continuing through 1945, cadmium was released in significant quantities by mining operations, and the disease first appeared around 1912.〔 Prior to World War II, the mining, controlled by the Mitsui Mining & Smelting Co., Ltd., increased to satisfy the wartime demand. This subsequently increased the pollution of the Jinzū River and its tributaries. The river was used mainly for irrigation of rice fields, but also for drinking water, washing, fishing, and other uses by downstream populations.〔 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 heavy metals, especially the cadmium. The cadmium accumulated in the people eating contaminated rice. When the population complained to Mitsui Mining & Smelting Co. about this pollution, the company built a basin to store the mining waste water before leading it into the river. This proved ineffective, and many had already been sickened. The causes of the poisoning were not well understood and, up to 1946, it was thought to be simply a regional disease or a type of bacterial infection.〔 Medical tests 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. Hagino and his colleagues suspect cadmium as the cause of the disease.〔 Toyama Prefecture also started an investigation in 1961, determining that the Mitsui Mining and Smelting's Kamioka Mining Station 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 ''itai-itai'' disease caused by the cadmium poisoning.〔Itai-itai disease http://www.kanazawa-med.ac.jp/~pubhealt/cadmium2/itaiitai-e/itai01.html〕 The reduction of the levels of cadmium in the water supply reduced the number of new disease victims; no new victim has been recorded since 1946. While the victims with the worst symptoms came from Toyama prefecture, the government found victims in five other prefectures. The mines are still in operation and cadmium pollution levels remain high, although improved nutrition and medical care has reduced the occurrence of itai-itai disease.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Itai-itai disease」の詳細全文を読む スポンサード リンク
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