Occupational chronic exposure to metals. II. Nickel exposure of stainless steel welders--biological monitoring.

Stainless steel welders (n = 103) were examined. To estimate external exposure, personal air sampling was used. Internal exposure was quantified by the determination of nickel levels in erythrocytes, plasma and urine. Men and women (n = 123) were examined for control purposes. In the plasma and erythrocytes of the controls the nickel concentration was below the level of detection (less than 1.8 micrograms/l). The element concentrations in urine were between less than 0.1 and 13.3 micrograms/l. Of the controls 95% showed nickel levels in urine below 2.2 micrograms/l (reference value). The average concentration of nickel in the air was 93 +/- 81 micrograms/m3. The average concentration of nickel in the plasma samples was 4.9 +/- 4.0 micrograms/l (95th percentile 12.8 micrograms/l). In erythrocytes nickel could not be detected. The nickel concentrations in the urine of the welders were 18.5 +/- 28.5 micrograms/l on average (95th percentile 52.5 micrograms/l). Only a weak correlation between the nickel levels of plasma and urine could be detected (Curine = 2.07 + 8.45 Cplasma; r = 0.294; p less than 0.01). Based on our results and on the reported literature a future limit value for the nickel concentration in urine should lay between 30 and 50 micrograms/l. This value corresponds to an external exposure of 500 micrograms nickel per cubic metre.