EVALUATION OF URINARY CADMIUM AND LEAD AS MARKERS OF BACKGROUND EXPOSURE OF MIDDLE-AGED WOMEN IN KOREA

Objective: The present study was initiated to investigate the validity of cadmium (Cd) and lead (Pb) in urine in comparison with the metals in blood as a biological marker of nonoccupational exposure of general populations to these metals as environmental pollutants. Design: Peri pheral blood samples, morning spot-urine samples, and 24-h total food duplicate samples were collected from 107 nonsmoking women (aged 30-59 years) in four urban and rural survey sites in Korea. Methods: Portio ns of the samples were digested by heating in the presence of mineral acids, and the digests were analyzed for Cd and Pb by graphite furnace atomic absorption spectrophotometry. The metal concentrations in urin e were adjusted for creatinine concentration and a specific gravity of 1.016. The analyte levels were evaluated on an individual basis (n = 107) and also on a group basis, i.e., in terms of geometric means for the survey sites (n = 4). Results: Cd in urine correlated with Cd in b lood on an individual as well as survey-site basis and tended to corre late with Cd in food duplicates on a group basis. The correlation of P b in urine with Pb in blood was weaker than that of Cd in urine with C d in blood when evaluated on an individual and survey-site basis. Pb i n urine correlated with Pb in food duplicates either weakly or even ne gatively when examined on a survey-site basis. Conclusions: Cd in urin e proved to be valid as a biological marker of environmental exposure of general populations, whereas less support was obtained for Pb in ur ine as an exposure marker.