CONCENTRATION OF CADMIUM IN RICE AND URINARY INDICATORS OF RENAL DYSFUNCTION

Objectives-(1) To examine the relation between concentrations of cadmi um (Cd) in rice and urinary concentrations of indicators of renal dysf unction and the prevalence of abnormalities in urine in areas polluted by Cd. (2) To establish the maximum allowable concentration of Cd in rice from these findings. Methods-The target population consisted of 1 703 inhabitants (832 men and 871 women) aged over 50 years who consume d home grown rice and had lived in the same hamlet in areas polluted b y Cd in the Kakehashi River basin in Ishikawa Prefecture, Japan for at least 30 years. The correlation coefficients between concentrations o f Cd in rice and several urinary substances, the prevalence of abnorma lities in urine and sex in hamlets polluted by Cd were calculated. Fin ally, regression analysis was performed for significant indicators to calculate the maximum allowable concentration of Cd in rice based on v alues in a control group. Conclusions-Significant correlations between concentration of Cd in rice and concentrations of urinary beta(2)-mic rogobulinuria, metallothioneinuria, glucosuria, proteinuria, proteinur ia with glucosuria, and aminonitrogenuria. The highest maximum allowab le concentration of Cd in rice calculated for these indicators was 0.3 4 ppm/l and 0.29 ppm/g creatinine. Both values are lower than 0.4 ppm, the tentative limit prescribed by the Japanese government.