Association between urinary indicators of renal dysfunction and metal concentrations in workers chronically co-exposed to cadmium, zinc and lead

The study was carried out in 31 workers co-exposed to cadmium, lead and zin c fumes and dusts in a zinc ore refinery. Urinary cadmium, lead, zinc, beta (2)-M levels and NAG activities were determined to evaluate the possible d ose-effect relationship between these parameters. A correlation was found b etween urinary cadmium, lead and zinc concentrations, and urinary beta (2)- M levels and NAG activities of the exposed group. A statistically significa nt increase was also observed for urinary NAG activity in exposed workers w ho had urinary cadmium concentrations >2 mug g(1) creatinine. However, in t he same exposed group, the increment of beta (2)-M was not statistically si gnificant. In conclusion, the present study thus confirms the earlier obser vations and may suggest the notion that the urinary NAG seems to be a more sensitive indicator than urinary beta (2)-M level in early stages of renal injury of moderately cadmium co-exposure with lead and zinc even at urinary cadmium concentration as low as 2 mug g(1) creatinine. When the earlier st udies on the irreversibility of cadmium-induced tubular dysfunction and the present results were taken into consideration, the present health-based bi ological limit proposed by the WHO (5 mug g(1) creatinine) seems to be high for the occupational exposure to cadmium.