Exposure to Solid Aerosols During Regular MMA Welding and Grinding Operations on Stainless Steel

Abstract

Tests of air concentrations of solid aerosols during manual metal arc (MMA) welding on stainless steel were carried out at three working sites. In addition to a detailed description of the work situation, samples of welding fume were collected from both the breathing zone and the general air. Air concentrations of total solid aerosols were determined gravimetrically. Total amounts of metal compounds (i.e., nickel (Ni), chromium (Cr), iron, and manganese) and water-soluble hexavalent chromium (CrVI), were determined. The mean fume concentrations during MMA welding were 5.4 mg/m3 inside a ship section, 3.0 mg/m3 at an offshore module, and 2.0 mg/m3in welding shops. The highest concentrations of CrVI were found during MMA welding inside the ship section, with a mean concentration of 140 µg/m3 (range 4–640 µg/m3). CrVIcomprised about 50% of the total Cr by weight. Though the base material contained approximately 20% Cr and 10% Ni, the Cr and Ni contents (µg/mg welding fumes) varied greatly among the different welding sites. Grinding generated a mean concentration of 11 mg/m3, of which Cr was about 10% of the total solid aerosol.