| With the rapid development of the electronics industry,the e-waste dismantling industry has emerged in southern and eastern China,and has been in the history of dismantling for about 30 years.Under the conditions of family workshopso for the cost-saving,original backward method causes serious emission of heavy metal and organic pollutants as well as adverse effects on local resident in the dismantling areas of southern and eastern China.Under China's Western Development Strategy,the e-waste recycling industry had also been moved to Northwest China with smaller population and from the relatively developed southern and eastern regions of China in order to reduce the emissions of toxic chemicals from dismantling process of E-waste.As a region with relatively backward economy and a fragile ecological environment,it have to bear the impact of the emission derived from toxic and hazardous chemicals during the industrial production process on the local ecosystem and the health of residents when harvesting the development opportunities by the western migration of the national industry.In the present thesis study,total 100 samples of atmospheric particle samples?PM1.0?PM2.5?PM10?were collected from three sampling sites?indoor and outdoor workplace of an formal E-waste dismantling plant,and a farmyard located at upwind area away five kilometers from the plant?during a period of continuous 10 Day in an formal E-waste dismantling plant in arid area of Northwest China.The contents of Polybrominated Diphenyl Ethers?PBDEs?and six heavy metals?Cd,Cr,Cu,Ni,Pb,and Zn?were analyzed by GC-MS and ICP-OES,respectively.Based on the observed data,the concentration levels,size distribution characteristics,emissions,and occupational exposure risks of heavy metals at indoor and outdoor dismantlingworkplaces were studied.The results were as followed: 1.PBDEs:?1?PBDEs concentration level: The ambient mean concentrations of ?9PBDEs in particle and gas phase over the sampling period followed a sequence of indoor > outdoor> background.The highest level of ?9PBDEs in PM2.5 at the indoor site was 1978.58 pg/m3.The highest concentration of ?9PBDEs in gas phase also occurred at the indoor site at 7.33 pg/m3,followed by the outdoor site?4.10 pg/m3?,and the control site?0.701 pg/m3?,indicating that the dismantling activities of e-waste dismantling plant still was an important emission sources of PBDEs.?2?PBDEs particle size distribution characteristics and congener profiles and gas-particle distribution: PBDEs in both indoor and outdoor of the dismantling workshop were mainly adsorbed on the particle phase,especially in PM2.5.BDE-209?50%-72%?was the most important congener in the particle phase of the dismantling workshop indoors,and BDE-28?45%-88.7%?was the most important congener in the gas phase.The percentage of high-bromined congener in the particulate phase was greater than that of the low-bromined congener,and the proportion of low-bromined congener?tribromo-BDE,tetrabromide-BDE?in the gas phase was greater than that of the high-bromined congener.The gas particle distribution behavior of the PBDEs in the indoor and outdoor of the dismantling workshop,it was prone to be absorbed in the particle phase both indoor and outdoor of dismantling workshop.?3?Emissions of PBDEs: The indoor environmental emissions of the E-waste dismantling workshop are estimated to be 0.081 to 5.15 g/d,which was 1-2 orders of magnitude lower than that of the southeastern and southern dismantling plants of China,and the emissions are relatively low.It shows that the management procedures for the standardized dismantling of the large-scale electronic waste dismantling plant can effectively reduce the pollutant discharge in the dismantling production activities.?4?PBDEs Occupational environmental inhalation exposure risk: The results show all detected PBDEs exposure risk values and total exposure risk values during the sampling period did not exceed the reference dose level.However,the flux of PBDEs deposited into the respiratory system indicates that PBDEs in fine particles are more likely to deposit in the alveolar region.Therefore,the long-term exposure to low doses is not a negligible health hazard for occupational workers.2.Heavy metals:?1?Heavy metal concentration level: Zn(4890 ng·m-3 in indoor,1245 ng·m-3 in outdoor)?Pb(indoor 1201 ng·m-3,outdoor 240 ng·m-3)and Cu(indoor 1200 ng·m-3,outdoor 110 ng·m-3)in the particles shown higher pollution level at indoor and outdoor of the dismantling workplace.Moreover,the indoor concentration was much higher than that of the outdoor,indicating that the dismantling activities were the main cause of high level of heavy metal contamination.The indoor and outdoor air pollution characteristics were closely related to the types of electronic waste dismantled.Particle size distribution characteristics: Heavy metals in the ambient environment of the dismantling workshop were mainly adsorbed in PM2.5,Followed by PM1.0,showed that heavy metals were easily adsorbed on fine particles.Heavy metals were mainly enriched in PM10 in the outdoor of the dismantling workshop,followed by absorbtion on PM2.5.?2?Heavy metal occupational exposure risk: Cr caused the greatest carcinogenic.The total non-carcinogenic hazard quotient?HQ?of indoor and outdoor dismantling workshops and the carcinogenic risk values were still far below the limits?1.0?and acceptable ranges(1×10-6)stipulated by U.S.EPA,indicating that the health risks caused by heavy metals were minor or negligible.?3?Characteristics of particulate heavy metals in the respiratory system: The sedimentation characteristics of particulate heavy metals in different organs of the human respiratory system exhibited that the smaller the particle size was,the greater the proportion of deposition in the depth of the respiratory system was.The results of this dissertation show that the heavy metals emitted by the E-waste dismantling plant that is built according to the national environmental protection requirements have relatively low health risks to occupational workers. |
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