Occupational Exposure to Cobalt and Nickel: Biological Monitoring

Abstract

Abstract Cobalt and nickel are industrially important metals which bear the risk of occupational cancer. In the health surveillance of workers biological monitoring provides a helpful means. For urine, we apply a complexation and extraction of the metals in an organic solvent with subsequent ETAAS determination. Clean-up and enrichment steps result in sensitive procedures whose accuracy has been proven, e.g. by voltammetry. Metal excretions of occupationally unexposed persons have been measured (Ni, n=123; m= 0.6 μg/L; 95%<1.8 μg/L; Co, n=123; m= 0.07 μg/L; 95%<0.71 μg/L). For blood and its compartments we minimized interferences by an eightfold dilution and by multistep decomposition before ETAAS determination. So we obtained simple and accurate direct procedures sensitive enough to monitor even low occupational exposures. Forty workers of a cobalt foundry were investigated. Average air concentrations at different working places ranged between 49 and 1046 μg/m3 which led to mean cobalt levels in whole blood between 4.9 and 47.9 μg/L and 18.9 and 438.4 μg/L urine, respectively. Between the individual blood (x) and urine levels (y) a significant linear correlation could be established (r= 0.862; y= 7.52x–11.2). In whole blood specimens, cobalt was bound not only to serum proteins but also to hemoglobin. A second study was performed for 103 stainless steel welders. The external nickel exposure did not exceed two-thirds of the German Technical Guiding Concentration of 500 μg/m3. The median nickel levels in body fluids were 3.9 μg/L (plasma) and 10.2 μg/L, respectively (urine). In none of the isolated individual erythrocyte fractions could nickel be quantified.