Occupational Exposure to Cadmium and Kidney Dysfunction

Investigations were carried out in an alkaline battery factory. The study group consisted of 102 persons and the control group of 85 persons. Cadmium in blood (Cd-B) and cadmium in urine (Cd-U), as well as beta 2-microglobulin (B2-M), retinol binding protein (RBP), amino acids in urine were determined. Exposure to cadmium was high; Cd-B and Cd-U concentrations were higher than recommended, 10 micrograms/l and 10 micrograms/g creat. In 65% and 56% of workers, respectively. Excretion of B2-M and RBP in urine was higher than the accepted upper limits of 380 and 130 micrograms/g creat. in about 20% of the workers. A significant correlation was observed between: log Cd-U.log Cd-B (r = 0.85), log B2-M.log RBP (r = 0.66), log Cd-U.log B2-M (r = 0.52), and log Cd-U.log RBP (r = 0.55). To evaluate the admissible period of occupational exposure to cadmium, an integrated exposure index (Cd-B x years of exposure) is proposed. According to the dose-response relationship, an increase of low molecular protein excretion in urine can be expected in 10% of the cases at Cd-U amounting to 10 to 15 micrograms/g creat. and Cd-B x years of about 300 to 400.