Search

A review of the epidemiological literature on the potential effects of land contamination shows that the largest body of contaminant-specific research relates to cadmium (Cd). First, a brief outline of the key issues related to the study of health impact of land contamination is presented. The recent literature is then reviewed for evidence of associations and possible causal relationships between exposure to Cd from land contamination and health impact. A large number of studies focusing on Cd arise because of the ready availability of biomarkers of exposure and effect and the demonstrated link between soil Cd and itai-itai disease (severe renal and bone disorders) via dietary exposure in Japan and China. Where dietary differences yield lower exposures, links have been established between Cd in soil and biomarkers of renal or bone dysfunctions, but not to health impacts per se. Potential effects of Cd exposure were also investigated for other health outcomes, including hypertension, cancer incidence, preterm delivery, and semen parameters. In contrast to renal and bone disorders, results are generally inconsistent and require further lines of evidence. Residence in locations with elevated concentrations of Cd in soil is a poor surrogate for exposure, and there are examples where residents in locations with elevated concentrations of Cd in soil did not appear to suffer serious health consequences.

Objectives: To assess and compare the background exposure of the general population to lead (Pb) and cadmium (Cd) in China and in Japan., Methods: Food duplicates and peripheral blood samples were collected from nonoccupationally exposed subjects, viz 202 Chinese women in four Chinese cities (Beijing, Shanghai, Nanning, and Tainan) and 72 Japanese women in three Japanese cities (Tokyo, Kyoto, and Sendai) in the years 1993-1995. Wet-ashing and graphite furnace atomic absorption spectrometric methods were used for the determination of Pb and Cd levels in food and blood samples., Results: Geometric mean (GM) dietary Pb intake (25.8 micrograms/day) and the GM Pb concentration in blood (56.7 micrograms/l) in Chinese were significantly higher than in Japanese women (11.6 micrograms/day in food and 32.1 micrograms/l in blood), whereas Cd in food (32.1 micrograms/day) and Cd in blood (1.92 micrograms/l) in Japanese were significantly higher than in Chinese women (9.9 micrograms/day in food and 1.07 micrograms/l in blood). The intake of Pb and Cd via boiled rice accounted for 3.6% and 31.1% of the total dietary burden in Chinese, and 12.1% and 32.7% in Japanese, respectively. The Cd burden was acquired almost exclusively through the dietary route, whereas the Pb burden came from both air and food, especially in the case of the Chinese population., Conclusions: The background Pb exposure in the Chinese population was higher than that in the Japanese population, whereas Cd exposure was lower in Chinese women than in their Japanese counterparts.