Significance of urinary cadmium concentration in a Japanese population environmentally exposed to cadmium.

An epidemiological study was performed on 1,815 cadmium-exposed and 240 nonexposed inhabitants of the Kakehashi River basin in Ishikawa, Japan. The significance of urinary cadmium concentration as an indicator of internal dose in a general environment polluted by cadmium was investigated. The mean urinary cadmium concentration (Cd-U) increased in a dose-related manner when the subjects were classified according to the average cadmium concentration in their village rice and according to their period of residence in the polluted area. As total cadmium intake increased, Cd-U also increased, and strong correlations were found (r = .93 in men and r = .88 in women). Therefore, it was concluded that, on a group basis, Cd-U is a useful indicator of the internal dose of environmental cadmium exposure.