Toyama Prefecture no relation cadmium
History
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.In the 1920s, levels of contaminated tailing waste increased after the creation of new froth flotation processes that boosted zinc production. Fine powdered mineral particles formed in the frothing process escaped and drifted downriver. These particles were subsequently oxidized into ions that were absorbed by aquatic plants, rice crops, fish, and subsequently, humans. Sphalerite, the main zinc containing ore in Komioka, is almost always coupled with greenockite, the only major cadmium-containing mineral in the world. Because of this, cadmium is a regular by-product of the zinc ore mining process. Up until 1948, cadmium was discarded as waste into the Jinzū River due to it being of no industrial value, exacerbating the levels of the element's release into the waterbody.Prior to World War II, the mining, controlled by the Mitsui Mining & Smelting Co., Ltd., increased to satisfy 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.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 kilometres (19 mi) 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.The reduction of the levels of cadmium in the water supply reduced the number of new cases; no new case has been recorded since 1946. While the people with the worst symptoms came from Toyama prefecture, the government found patients with itai-itai disease in five other prefectures.
After the first reports of Itai-Itai in 1912, it took 55 years for the epidemiological investigation to discover that the disease was due to cadmium poisoning. Delayed bureaucratic response was a common thread in the Four Big Pollution Diseases of Japan.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.Cadmium pollution in Jinzū river
Over time, the cadmium that was released as industrial waste began to accumulate in the soil, algae and river organisms. This resulted in the local phytoplankton and algal species absorbing it in high quantities. Cadmium was subsequently passed through the food web to fish consumers. Fish also bioaccumulated cadmium through passive transport in the gills. Cadmium adversely affected fish, causing endocrine disruption and inhibited reproduction, and sometimes mortality.Due to the residents being unaware of the cadmium and its dangers, they used the water from the Jinzū to irrigate their rice fields. Cadmium is highly water-soluble and the rice paddies' prolonged exposure led to the rice quickly becoming contaminated and toxic. The local resident's consumption of this rice and drinking water then resulted in elevated cadmium body burdens – leading directly to symptoms characteristic of itai-itai disease. Cadmium is now considered one of the most dangerous toxic metals due to its ability to threaten food safety through being easily be absorbed into the rice paddies, then subsequently the rice.
no relation