Chromium-induced early changes in renal function among ferrochromium-producing workers

Abstract

Urinary biochemical indicators of renal injury were examined in 84 male and 38 female ferrochromium-producing workers exposed to water-soluble chromium compounds [Cr(VI)]. The indicators examined included urinary chromium (U-Cr), alkaline phosphatase (ALP), gamma-glutamyl transferase (γ-GT), glutamic-oxalacetic and glutamic-pyruvic transaminases (GOT & GPT), lactate dehydrogenase (LDH), N- acetyl-β- d- glucosaminidase (NAG), total protein (TPr) and β 2-microglobulin ( β 2-MG). The U-Cr levels in the exposed group were approximately 1.8 times that of the control group. Compared to controls, the activities of γ-GT, NAG, ALP, GOT and LDH in the urine of workers were significantly increased whenever U-Cr concentration exceeded 45 μg/g creatinine. The activities of γ-GT, GOT and NAG were elevated in workers employed for longer than ten years. However, no clear dose-response relationships nor time-effect relationships were found. The present results suggest that long-term exposure to water-soluble chromium [Cr(VI)] produces chronic renal injury. The site of the injury appears to mainly involve the proximal tubule. U-Cr concentrations of > 15 μg/g creatinine can be proposed as a threshold dosage for nephrotoxicity, and γ-GT, NAG and ALP are early sensitive indicators of the most valuable for evaluating the renal injury.