Notable case, Toyama, Toyama Prefecture, Japan
Jinzū River basin (itai-itai disease)
神通川
The rice paddies along the lower Jinzū, irrigated for decades with water carrying cadmium from the Kamioka zinc and lead mine. People who ate the rice developed itai-itai ("ouch-ouch") disease, a severe disorder of bones and kidneys.
At a glance
- Status
- Remediated
- Area
- 1,686 ha on land1
- Activity
- 1910–1945
- People affected
- 196 (2012)2
- Media
- soil, surface water, sediment, living organisms
- Kind of site
- mining, smelter
- Area. 1,686 hectares of rice paddies covered by Toyama Prefecture's restoration plan; 863 hectares restored by the public programme and a further 120 by farmers themselves (2012 figures). The map point is the river mouth; the Kamioka mine lies about 40 km upstream, in Gifu Prefecture.
- People affected. People recognised as itai-itai victims up to 2012 (Japan for Sustainability).
Contaminants
Status
Remediated
Restoration of the paddies ended in March 2012 after 33 years. Discharges from the Kamioka mine have been checked since 1972 through yearly inspections in which residents take part; cadmium discharge fell from 35 kg a month in 1972 to 3.8 kg a month in 2010 (Wikipedia, citing Kaji 2012).
Story
The Kamioka mine, owned by Mitsui Mining and Smelting, extracted zinc, lead and silver in the upper Jinzū valley, in Gifu Prefecture. From 1910 to 1945 its processing plant released cadmium into the river. Downstream, on the Toyama plain, the water was used to irrigate rice and for household needs: cadmium built up in the soil and in the rice.
The first cases of the disease date from about 1912. In 1955 the physician Noboru Hagino and colleagues named cadmium as the cause; in 1968 the Ministry of Health and Welfare confirmed it officially. That year 29 people sued Mitsui: the court found for them in June 1971 and the company's appeal was rejected in August 1972. Since then residents have had the right to inspect the mine every year.
In 1979, after cadmium had been found in brown rice, Toyama Prefecture began restoring the paddies by replacing or covering the cultivated layer with clean soil. Work ended in March 2012: 863 hectares restored out of the 1,686 in the plan, at a cost of 40.7 billion yen shared between Mitsui, the state, the prefecture and the city of Toyama.
Timeline
- 1910Cadmium release from the Kamioka mine into the river begins (until 1945).
- 1912First cases of the disease, around this date.
- 1955Hagino and colleagues name cadmium as the cause.
- 1968Official recognition as a pollution-caused disease; 29 people sue Mitsui.
- 1972The company's appeal is rejected; yearly inspections of the mine begin.
- 1979Toyama Prefecture starts restoring the paddies.
- 201217 March: ceremony marking the end of the restoration works.
Health
Itai-itai is osteomalacia with kidney damage from long-term cadmium exposure; it is named after the severe pain in bones and spine. By 2012, 196 people had been recognised as victims (Japan for Sustainability).
Remediation
- 1972source controlControl of mine discharges with yearly inspections attended by residents; more than 20 billion yen spent on source measures and 75 hectares reforested (2011 figures, Toyama Prefecture).
- 1979soil replacementReplacement or covering of the cultivated layer of the paddies with soil brought from elsewhere: 863 hectares between 1979 and 2012, cost 40.7 billion yen.
From the literature
Species that acted on one of this site's contaminants in at least one study. The list is automatic and takes no account of this site's soil, concentrations or climate.
Plants
- Agrostis capillarisCommon bentEvidence: field
- Arabidopsis halleriHaller's rockcressEvidence: field
- Cannabis sativaIndustrial hempEvidence: field
- Festuca rubraRed fescueEvidence: field
- Noccaea caerulescensAlpine pennycressEvidence: field
- Ricinus communisCastor beanEvidence: field
Fungi
- Paxillus involutusBrown roll-rimEvidence: greenhouse
- Rhizophagus irregularisEvidence: greenhouse
- Agaricus bisporusButton mushroomEvidence: laboratory
- Aspergillus nigerBlack mouldEvidence: laboratory
- Mucor circinelloidesEvidence: laboratory
- Oidiodendron maiusEvidence: laboratory
The rest are on the contaminant pages.
Nearby
Sources
- Taking back the beautiful water and land by the countermeasures against environmental damage, Toyama Prefectural Itai-itai Disease Museum
- Toyama Prefecture Completes Restoration Project for Cadmium-Contaminated Rice Paddies along Jintsu River, Japan for Sustainability, 2012
- Itai-itai disease, Wikipedia, 2026
- Jinzū River, Wikipedia, 2026
Draft compiled from public sources, not yet reviewed.