The Release And Exposure Risk Assessment Of PAHs And PCBs During WPCB Heating Process

One of e-waste dismantling plants in Shanghai where wiring printed circuit boards?WPCB?were dismantled by workers was taken as research object in this study.Polycyclic Aromatic Hydrocarbons?PAHs?and polychlorinated biphenyls?PCBs?were released from WPCB during thermal process,some PAHs and PCBs were released to air,while others went through the flue pipe,which were collected by cyclone dust collector.In order to detect PAHs concentration,PUF plugs,linen and yarn were exposed to PWB-heating workshop to absorb PAHs naturally.It turned out that with the exposure time increasing,the variety of individual PAHs increased whose concentrations basically rose except Nap.That's because Nap probably was converted to other individuals.In addition,PAHs concentrations adsorbed by PUF plugs within 14 days were linearly related with exposure time,and based on linear analysis the rate of adsorption by PUF plugs is 6.684 mg.m^-3.d^-1.Linen and yarn which were also exposured to PWB-heating workshop both preferred to adsorb 3,4-ring PAHs,and low molecular PAHs were easily adsorbed on linen while high molecular PAHs were easier to adsorbed on yarn.To further investigate the release and adsorption mechanisms of PAHs as well as PCBs,the dust collected from cyclone dust collector was heated in a quartz tube furnace.The results showed that the potential maximum adsorption concentrations of PAHs at 200 and 250^oC were 556and 391ng/g repectively,and that of PCBs at 200 ^oC was 24236.8ng/g.with temperature going up,the number of individual PAHs decreased and some of high molecular PCBs were degraded to low molecular PCBs.Besides,the heating process of dust led to two outputs,one was residual PAHs and PCBs in dust,the other was PAHs and PCBs emission.96%⁹9%PAHs were emitted and the percentage of PCBs emission were89%⁹4%from the heating dust.Furthermore,as temperature rose,the emission of them gradually increased.According to the research of PCBs adsorbed by cotton,linen and yarn,the order of adsorption effects was cotton<linen<yarn,and high molecular PCBs preferred to be adsorbed by yarn.Therefore,clothes made of cotton were suggested to be worn by workers.Based on PM2.5 and TSP samples collected from different functional areas in the diamantling plant,average daily exposure was calculated and health risk was evaluated including cancer risk and non-cancer risk.The results demonstrated that There didn't exist cancer risk in all of the function districts,while non-cancer risk existed in workshop.Moreover,since there exists high concentration of PCBs in air,they are suggested wearing particulate respirators.