Abstract
Cause of the strange osteomalacia “itai-itai” disease which appeared in the Jinzu River basin, Toyama Prefecture, was concluded to be a public hazard induced by cadmium in the waste water from a mine.
In Annaka City, Gunma Prefecture, where the largest zinc refinery of Japan is located, many samples of agricultural products and soils were collected in October 1968 and June 1969 and analyzed to verify actual conditions of pollution by the refinery.
As a result, it was found that the content of cadmium and other metals in mulberry leaves for silk worm or wheat flour is remarkably related to the distance (220-2, 500m) from the refinery chimney, and further, that the content of cadmium and other metals is remarkably higher in leaf vegetables such as cabbages (Cd 60-3ppm, Zn 7, 000-300ppm, Pb 370-4ppm in dry matter) compared with root vegetables (potato, carrot, radish), fruit vegetables (tomato, squash, eggplant), or cereals (barley, wheat, rice, corn). Nevertheless, the pollution of the latter has to be considered. Thus, it was made clear that principally the hilly regions are polluted by metal contained air, and that lower rice field regions are also affected by polluted air as well as waste water.
