Characterization of welding fume and airborne heavy metals in electronic manufacturing workshops in Hangzhou, China: implication for occupational population exposure

Abstract

Occupational exposure to contaminants created by electronic manufacturing process is not well characterized. The aim of this study was to carry out risk assessments of exposure to welding fume and airborne heavy metals (HMs) in electronic manufacturing workshops. Seventy-six air samples were collected from five sites in Hangzhou, China. In welding workshops, the most abundant contaminant found was welding fume, followed by Fe, Mn, Zn, Cu, Pb, Cd and Cr. The concentration of Mn was positively correlated with Fe (r = 0.906). When compared with non-welding workshops, the Fe content in the air of welding workshops increased significantly (P<0.05), while the Cu content decreased significantly (P<0.05). Singapore semi-quantitative health risk assessment model and EPA inhalation risk assessment model were applied to assess the occupational exposure. In welding workshops, the levels of 8h-TWA calculated for welding fume (range 0.288~6.281 mg/m 3 ), Mn (range Nd~0.829 mg/m 3 ) and Fe (range 0.027~2.234 mg/m 3 ) partly exceeded the permissible limits. While, in non-welding workshops, the average of 8h-TWA for Cu (0.411 mg/m 3 ) was higher than the limit. The risk rates (RR) assessed for Pb (2.4 vs 1.7). Mn (2.0 vs 1.4) and Fe (1.4 vs 1.0) were higher in welding workshops than that in non-welding workshops, but Cu (1.0 vs 2.2) were lower. The mean excess lifetime cancer risks (ELCR) in welding (5.59E-06 per 1000 people) and non-welding (1.88E-06 per 1000 people) workshops were acceptable. The mean non-cancer risks (HQ) estimated for Mn was greater than 10 in both welding (HQ=164) and non-welding (HQ=11.1) workshops. These results indicate that there was a risk of occupational exposure implication in the electronic manufacturing workshops. It's thus suggested reducing contaminant exposure through engineering controls and management strategies, such as efficient ventilation and reducing exposure hours.