Itai-itai disease

The symptoms of Itai-Itai disease were first observed in 1913 and characterized between 1947 and 1955; it was 1968, however, before the Japanese Ministry of Health and Welfare officially declared that the disease was caused by chronic cadmium poisoning in conjunction with other factors such as the stresses of pregnancy and lactation, aging, and dietary deficiencies of vitamin D and calcium. The name arose from the cries of pain, "itai-itai" (ouch-ouch) by the most seriously stricken victims, older Japanese farm women. Although men, young women, and children were also exposed, 95% of the victims were post-menopausal women over 50 years of age. They usually had given birth to several children and had lived more than 30 years within 2 mi (3 km) of the lower stream of the Jinzu River near Toyama.

The disease started with symptoms similar to rheumatism, neuralgia, or neuritis. Then came bone lesions, osteomalacia, and osteoporosis, along with renal disfunction and proteinuria. As it escalated, pain in the pelvic region caused the victims to walk with a duck-like gait. Next, they were incapable of rising from their beds because even a slight strain caused bone fractures. The suffering could last many years before it finally ended with death. Overall, an estimated 199 victims have been identified, of which 162 had died by December 1992.

The number of victims increased during and after World War II as production expanded at the Kamioka Mine owned by the Mitsui Mining and Smelting Company. As 3,000 tons of zinc-lead ore per day were mined and smelted, cadmium was discharged in the wastewater . Downstream, farmers withdrew the fine particles of flotation tailings in the Jinzu River along with water for drinking and crop irrigation . As rice plants were damaged near the irrigation inlets, farmers dug small sedimentation pools that were ineffective against the nearly invisible poison.

Both the numbers of Itai-Itai disease patients and the damage to the rice crops rapidly decreased after the mining company built a large settling basin to purify the wastewater in 1955. However, even after the discharge into the Jinzu River was halted, the cadmium already in the rice paddy soils was augmented by airborne exhausts. Mining operations in several other Japanese prefectures also produced cadmium-contaminating rice, but afflicted individuals were not certified as Itai-Itai patients. That designation was applied only to those who lived in the Jinzu River area.

In 1972 the survivors and their families became the first pollution victims in Japan to win a lawsuit against a major company. They won because in 1939 Article 109 of the Mining Act had imposed strict liability upon mining facilities for damages caused by their activities. The plaintiffs had only to prove that cadmium discharged from the mine caused their disease, not that the company was negligent. As epidemiological proof of causation sufficed as legal proof in this case, it set a precedent for other pollution litigation as well.

Despite legal success and compensation, the problem of contaminated rice continues. In 1969 the government initially set a maximum allowable standard of 0.4 parts per million (ppm) cadmium in unpolished rice. However, because much of the contaminated farmland produced grain in excess of that level, in 1970 under the Foodstuffs Hygiene Law this was raised to 1 ppm cadmium for unpolished rice and 0.9 ppm cadmium for polished rice. To restore contaminated farmland, Japanese authorities instituted a program in which, each year, the most highly contaminated soils in a small area are exchanged for uncontaminated soils. Less contaminated soils are rehabilitated through the addition of lime, phosphate, and a cadmium sequestering agent, EDTA.

By 1990 about 10,720 acres (4,340 ha), or 66.7% of the approximately 16,080 acres (6,510 ha) of the most highly cadmium contaminated farmland had been restored. In the remaining contaminated areas where farm families continue to eat homegrown rice, the symptoms are alleviated by treatment with massive doses of vitamins B1, B12, D, calcium, and various hormones. New methods have also been devised to cause the cadmium to be excreted more rapidly. In addition, the high costs of compensation and restoration are leading to the conclusion that prevention is not only better but cheaper. This is perhaps the most encouraging factor of all.

See also Bioaccumulation; Environmental law; Heavy metals and heavy metal poisoning; Mine spoil waste; Smelter; Water pollution

[Frank M. D'Itri ]

RESOURCES

BOOKS

Kobayashi, J. "Pollution by Cadmium and the Itai-Itai Disease in Japan." In Toxicity of Heavy Metals in the Environment, Part 1, edited by F. W. Oehme. New York: Marcel Dekker, 1978.

Kogawa, K. "Itai-Itai Disease and Follow-Up Studies." In Cadmium in the Environment, Part II, edited by J. O. Nriagu. New York: Wiley, 1981.

Tsuchiya, K., ed. Cadmium Studies in Japan: A Review. Tokyo, Japan, and Amsterdam, Netherlands: Kodansha and Elsevier/North-Holland Biomedical Press, 1978.