Urinary chromium as an indicator of the exposure of welders to chromium.

Abstract

Welders (5) working with high alloy Cr-Ni steel and 1 working with mild steel were followed during 1 work week. The Cr concentration in air was measured concomitantly with urinary Cr determinations. The water-soluble Cr concentrations in air exceeded 0.05 mg/m3 during welding with coated electrodes, but metal inert-gas (MIG) welding produced much lower concentrations. The proportion of water-soluble hexavalent Cr in the air was usually more than 50% of the total Cr concentration during welding with coated electrodes; less than 10% of the Cr produced during MIG welding was in a water-soluble form. Since water-soluble Cr (hexavalent) is the more important biologically, the determination of both water-soluble and water-insoluble Cr concentrations is emphasized instead of the measurement of the total concentration. The urinary Cr concentration was a good indicator of short-term exposure to water-soluble Cr when exposure was above the current threshold limit value of 0.05 mg/m3, concentrations of more than 30 .mu.g/g of creatinine representing an exposure level higher than the threshold limit value.