【作者】 马静；

【导师】 王文华； Kurunthachalam Kannan；

【作者基本信息】 上海交通大学 ， 环境科学， 2009， 博士

【摘要】 随着电子信息等高科技产业的迅猛发展,废弃电子电器(又称电子垃圾)成为了增长速度最快的固体废物。每年全世界大约有2～5千万吨的电子垃圾产生,其中70%被运至中国拆解回收,而就中国自身而言,每年还要废弃大约4百万台电脑。浙江台州已成为国内目前最大的电子垃圾拆解基地之一,年拆解量超过2百万吨,约4万人从事拆解工作。废弃电子电器在国内的不当拆解,导致持久性有毒污染物经各种途径的排放不断上升,污染状况呈现恶化趋势,因排放量、暴露计量的增加造成的环境安全和健康问题日趋严重,已引起国内外各界的高度关注。然而目前对于台州地区电子垃圾不当拆解造成的污染水平、污染特征以及拆解工人暴露危害的状况还缺乏系统的研究。为了全面了解台州地区电子垃圾拆解基地对周边环境造成的污染水平、污染特征以及拆解工人的暴露危害状况,本论文建立并优化了多种痕量、超痕量持久性有毒有机污染物在多介质样品中的前处理技术,实现了少溶剂高回收率的多组分同步净化。突破了高溴取代物质仪器分析的瓶颈,采用GC/MS、HRGC/HRMS和GC-ECD仪器检测方法的结合,研究了浙江台州废弃电子电器拆解地区多环境介质(表层土壤、灰尘、植物叶片和电子垃圾碎屑)以及拆解工人头发样品中持久性有毒卤代烃(包括多溴联苯醚(PBDEs)、氯代二噁英(PCDD/Fs)、溴代二噁英(PBDD/Fs)、氯代多环芳烃(ClPAHs)和母体多环芳烃(PAHs))的浓度水平、污染特征、来源解析;同时选取背景对照点(农业地区)和不同功能区对照点(传统化工区)的土壤样品进行比较。主要研究结果与结论如下:PBDEs在废弃电子电器拆解地各环境介质中100%检出,平均最高浓度出现在拆解过的电子垃圾碎屑中,最高浓度甚至达到了163000 ng/g dw。拆解地区土壤中∑PBDEs高出化工区和农业背景对照点土壤浓度约2～3个数量级。PBDEs浓度指纹图谱与商用多溴联苯醚混合物deca-BDE和penta-BDE的浓度指纹相似程度较高,从而推断电子电器及其包装材料中使用的添加型商用溴代阻燃剂,在不当的拆解过程中大量释放到周围环境中,成为PBDEs主要的潜在释放源。PCDD/Fs在电子垃圾拆解地各环境介质中100%检出,∑PCDD/Fs最高平均值出现在拆解车间地面灰尘中(最高达到111000 pg/g dw)。拆解地土壤中浓度约为化工和农业对照点土壤浓度的12倍和200倍。PCDD/Fs同系物/同族体指纹图谱与文献报道的PCDD/Fs释放源指纹图谱相似。且土壤中浓度超过了欧美等国规定的土壤中PCDD/Fs最大允许阈值,存在一定的环境污染风险。PBDD/Fs仅在电子垃圾拆解地各环境介质中检出,对照点未检出;其污染特征与氯代二噁英相似,但大部分样品中PBDD/Fs的毒性当量高于相应的PCDD/Fs的毒性当量。由此表明废弃电子电器的不当拆解已成为氯代及溴代二噁英的主要释放源,且溴代二噁英被认为是在电子垃圾不当拆解过程中产生的新的特征性持久性有机污染物。对废弃电子电器拆解地3环以上ClPAHs的首次研究发现拆解地各环境介质中ClPAHs100%检出,拆解地土壤中浓度高出农业背景对照点土壤浓度约178倍,传统化工区土壤中ClAPHs浓度处于和电子垃圾拆解地各环境介质中相当的浓度。母体PAHs在电子垃圾拆解地各环境介质中浓度分布为150～49700 ng/g dw,且∑ClPAHs和∑PAHs之间,6-ClBaP和BaP之间均具有显著相关性。结合QSAR和多介质逸度模型对ClPAHs的预测发现,随着氯原子取代数的增加,ClPAHs的毒性可能会有所增加,且在环境中更趋向富集于土壤和底泥中。部分样品中ClPAHs的毒性当量要大于相应的PCDD/Fs和PBDD/Fs毒性当量。由此表明废弃电子电器拆解地和传统化工区一样是ClAPHs的主要释放源,且区域污染特征明显。其ClPAHs和母体PAHs相关性的研究表明ClPAHs,尤其是6-BaP,很可能是由BaP氯化产生;ClPAHs具有和二噁英类似的环境行为。超过90%的拆解工人头发中有PBDEs和PCDD/Fs的检出,且PBDEs和PCDD/Fs的浓度高出普通居民头发中浓度4倍和18倍,工人头发与植物叶片中PBDEs和PCDD/Fs的指纹图谱分别相吻合,从而表明头发中的PBDEs和PCDD/Fs主要来自外源污染。综合比较5种持久性有毒卤代烃浓度、毒性当量和相关性发现,废弃电子电器拆解地受5种持久性有毒卤代烃的污染程度大于传统化工园区和农业背景区域;PCDD/Fs、PBDD/Fs和ClPAHs的浓度低于PBDEs和PAHs,但其毒性当量浓度却占5种持久性有毒卤代烃总毒性当量的主要份额;各污染物之间存在显著相关性。由此表明电子垃圾不当拆解已成为持久性有毒污染物更为严重的释放源;长期在高毒性有机污染物暴露下的拆解工人具有较高的健康风险;各污染物之间相关性显著,表明它们之间存在相互影响,可能存在复合污染效应。采用VlIER-HUMAAN暴露模型,估算了五种持久性有毒卤代烃在土壤/灰尘的摄入、皮肤接触和吸入大气中可吸入颗粒物的三种非膳食性暴露途径下的日摄入量,结果表明非膳食性摄入为主的暴露途径符合职业暴露的特点。结合文献数据得出对PCDD/Fs的总日摄入量接近世界卫生组织(WHO)1998年制定的TCDD每日耐受量上限(TDI,1～4 pg TEQ/kg bw/day),PBDD/Fs的总日摄入量高出该耐受上限的2倍。BDE 99的最大允许摄入量高出文献报道最大允许摄入量的2倍;ClPAHs和PAHs的初步致癌风险评估表明均在可接受的风险等级。由此表明拆解工人存在一定的职业暴露危险。更多还原

【Abstract】 Electrical and electronic waste (E-waste) has become the fastest growing stream among all the solid waste around the worldwide with the development of the electronic information technology. Environmental pollution arising from e-waste disposal and recycling facility has received considerable attention in recent years in China. Approximately, 20-50 million metric tons of e-wastes are produced worldwide every year, if which 70% is exported to China for recycling. Taizhou has become one of the largest recycling centers in China which employes around 40000 people for recycling, and approximately 2.2 minllion metric tons of e-wastes are dismantled there annually. Treatment, at low temperatures, of e-waste, that contain polyvinylchloride and related polymers can release persistent halogenated hydrocarbons (PHHs), such as polybrominated diphenyl ethers (PBDEs), polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs), polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/Fs), chlorinated polycyclic aromatic hydrocarbons (ClPAHs) and parent polycyclic aromatic hydrocarbons (PAHs). Nevertheless, little is known about the concentrations, profiles, and estimated human exposures for these PHHs from e-waste recycling facility in China.In this study, reliable analysis and instrument methods were built up. Electronic shredder waste, workshop-floor dust, leaves, surface soil and human hair sample of the recycling workers collected from a large scale e-waste recycling facility in Taizhou, eastern China, were analyzed for these PHHs. At the same time, surface soils from agricultural areas in eastern and central China were also collected as the background comparison, and surface soils from an traditional chemical industrial complex in Shanghai were collected as different functional area comparison in order to show the characteristic persistent organic pollutants in e-waste recycling facility.10 PBDE congeners were detected all samples, the highest mean concentration of PBDEs were found in electronic shredder waste (45500 ng/g dw), and the highest value was even 163000 ng/g dw. The mean concentration of total PBDEs in soil from the e-waste facility was approximately 2 orders of magnitude higher than the concentrations in soils from the chemical industry complex and approximately 3 orders of magnitude higher than the concentrations in agricultural soil, suggesting that a major emission source of PBDEsis the low-tech e-waste recycling facilities. The PBDEs profiles in our samples were comparable with the commercial penta-BDE and deca-BDE products, which showed the brominated flame retardants employed in electrical and electronic appliances were the major emission source during the low-tech recycling facility.PCDD/Fs congeners were detected all samples, concentrations of total PCDD/Fs were highest in workshop-floor dust (1240～111000 pg/g dw,mean, 39800 pg/g dw). The mean concentration of total PCDD/Fs in soil from the e-waste facility was approximately 12 times higher than the concentrations in soils from the chemical industry complex and approximately 200 times higher than the concentrations in agricultural soil. The profiles of PCDD/Fs in our samples were similar with the profiles of other PCDD/Fs emission sources reported in the literatures. PBDD/Fs were only detected in samples from e-waste recycling facility, which suggested PBDD/Fs were the new characteristic persistent organic pollutants in low-tech e-waste recycling facility. The profiles of PBDD/Fs were similar with the chlorinated dioxins and furans, and the TEQ values of PBDD/Fs were higher than those of PCDD/Fs in most samples. We suggested the low-tech e-waste recycling facility was the major emission source of chlorinated and brominated dioxins and furans.We also firstly reported the 100% detection of ClPAHs in multiple samples from e-waste recycling facility. The mean concentration of total PCDD/Fs in soil from the e-waste facility was approximately 178 times higher than the concentrations in agricultural soil, and the concentrations in soils from the chemical industry complex were comparable with the concentrations in multiple samples from e-waste recycling facility. Concentrations of 16 parent PAHs were high (150～49700 ng/g dw) in samples collected from the e-waste recycling facility. Significant correlation betweenΣClPAH andΣPAH concentrations suggests that direct chlorination of parent PAHs is the major pathway of formation of ClPAHs during e-waste recycling operations. We predicted the chemical and physical characters of 20 ClPAHs and their fate in environment by QSAR and multimedia fugacity model LevelⅢ, which suggested the toxicity of ClPAHs could increase with the increasing chlorination level, and ClPAHs having the similar fate with dioxins could be ready to accumulate in soil and sediment in standard environment. The TEQ concentrations of ClPAHs found in multiple environmental matrices in this study were higher than the TEQ concentrations of PCDD/Fs and PBDD/Fs in the same samples. We suggested the low-tech e-waste recycling facility was the major emission source of chlorinated PAHs, and so did in chemical industrial complex.The concentrations of PBDEs and PCDD/Fs in recycling workers’hairs were higher than those in residents’hairs. The Profiles of PBDEs and PCDD/Fs in hairs from recycling worker were comparable with those in hairs from residents, suggested the PBDEs and PCDD/Fs in human hairs were mainly exotic pollution.Combined pollution effect of five PHHs could be paid more attention because of the elevated concentrations, high TEQ values, and the significant correlations among each others.VlIER-HUMAAN model was applied to calculated the estimated daily intakes of TEQs of PBDEs, PCDD/Fs, PBDD/Fs, ClAPHs, and parent PAHs via non-dietary exposure pathways. And the results showed that the estimated daily intakes from soil/dust ingestion > that from dermal absorption > that from particulate inhalation. The estimated daily intakes of PCDD/Fs were very close to the upper bound of WHO 1998 tolerable daily intake (TDI, 1～4 pg TEQ/kg bw/day), and the estimated daily intakes of PBDD/Fs were 2 times higher than TDI. Hazard index (HI) of PCDD/Fs for children was 2.25, qualitative descriptor suggested low noncancer toxic risks, and HI of PCDD/Fs for children was 0.222, qualitative descriptor suggested minimal noncancer toxic risks. The estimated daily intakes of BDE 99 exceeded the tolerable daily intake from reference about 2 times. All of the calculated risk of ClAPHs and parent PAHs were deemed acceptable risk level.更多还原