| Summary: | 碩士 === 國立高雄第一科技大學 === 環境與安全衛生工程研究所 === 100 === This study was conducted to investigate the characteristics and occupational health impacts of particle matter emitted from inert-gas metal-arc welding process in a steel tank manufacturing factory. Welding fumes were collected in different process areas (welding, assembly and polishing) by a nano micro-orifice uniform-deposit impact (nano-MOUDI) for particle size distributions and by personal environmental monitor (PEM2.5) for exposure determination. Collected welding fumes samples were analysed for heavy metals (Fe, Zn, Mn, Ca, Mg, Cu, Al, Cr, Ni, Sn and Ti) by ICP-OES.
The health risk for employee exposure to heavy metals in the factory was further estimated based on the results of exposure assessment. Results obtained from nano-MOUDI sampling show that the highest PM concentrations in welding, assembly and polishing areas were observed in the cut-size diameters of 180(0.09 mg/m3) & 8nm (0.08 mg/m3), 100(0.07 mg/m3) & 32 nm(0.06 mg/m3), and 100(0.07 mg/m3) & 32 nm(0.06 mg/m3), respectively. In welding area, the most abundant metals measured in differenr size ranges were Fe (32-1000 nm), Zn (1800-3200 nm) and Ca (10-18 nm), respectively. The most abundant metals found in assembly and polishing areas were also Fe (assembly: 32-3200 nm, polish: 100-3200 nm) and Ca (assembly: 10-18 nm, polish: 10-56 nm). Results obtained from personal PM2.5 sampling in the welding, assembly and polishing areas were 6.49, 1.85 and 0.91 mg/m3, respectively.
The cancer risk of inhalation exposure to metals for the workers in welding, assembly and polishing processes were 2.05E-02, 8.61E-03 and 6.11E-03, respectively. The key metal pollutants that contributed most to the overall cancer risks were Cr and Ni.
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