Integrated index of occupational exposure to cadmium as a predictor of kidney dysfunction

In a study carried out in an alkaline battery factory, the study group consisted of 141 factory workers exposed to cadmium, while 206 workers in the textile industry constituted the control group. Cadmium in blood (Cd-B), cadmium in urine (Cd-U) as well as beta 2-microglobulin and retinol-binding protein (RBP) in urine were determined. Exposure to cadmium in the factory was high. In 1988, Cd-B concentrations in different departments averaged 11.2-29.9 micrograms/l. To evaluate the admissible period of occupational exposure to cadmium, an integrated exposure index [Cd-B (micrograms/l) x years of exposure] is proposed. According to the dose-response relationship, an increase in low molecular weight protein excretion in urine can be expected in 10% of subjects at an integrated exposure index of about 300 micrograms/l x years of exposure. The data obtained confirmed the validity of the recommended health-based limits for occupational exposure of 10 micrograms/l and 10 micrograms/g creatinine for Cd-B and Cd-U respectively.