Abstract:
The objective of this research was to evaluate the risk of inhalation exposure to heavy metals and polychlorinated biphenyls (PCBs) in electronic waste dismantling workers. The highest average exposure concentrations of total heavy metals in PM2.5-10 and PM2.5 were found to be 5.45±0.94 and 10.42±1.17 µg/m3, respectively. The concentration obtained from the workers involved with wire burning was significantly higher than those of other activities, including dismantling large, small, and internal parts of e-waste, approximately 1.5 to 2.7 and 1.9 to 8.2-folds for PM2.5-10 and PM2.5, respectively. Whilst, the average exposure concentrations of total PCBs in PM2.5-10, PM2.5, and gas were found at 53.17±23.64, 63.53±22.64, and 81.90±84.85 ng/m3, respectively. The highest exposure concentration of total PCBs in PM2.5-10 could be measured from dismantling internal parts of e-waste with the value of 86.09±6.39 ng/m3, while those of PM2.5 and gas released from wires burning were found to be the highest at 86.90±23.39 and 213.35±61.83 ng/m3, respectively. Comparing dismantling activities, exposure to the total gaseous PCBs from wire burning was approximately 3.7 to 7.1-folds higher than those of the others. Regarding the assessment for non-carcinogenic risk, the 95% confidence interval (CI) of hazard quotient (HQ) of exposure to As in PM2.5-10 and PM2.5 were 1.62-2.28 and 1.51-2.89, respectively, which were over the acceptable level (HQ ≤1). Considering the total lifetime cancer risk (TLCR) of all worker groups who dismantle for 30 years approximately, the 95% CIs of exposure to As, Cd, Cr, Ni, and Pb in PM2.5-10 and PM2.5 were totally estimated at unacceptable risk (TLCR > 10-6), in particular, the highest risk was found for the workers involving with wire burning. Similarly, the highest TLCR of exposure to PCBs was assessable in the group of wire burning with the 95% CI of 1.32-1.96 x 10-5 indicating this worker group has a greater potential of carcinogenic effects than the others.