【作者】 沈超峰；

【导师】 陈英旭； 王子健；

【作者基本信息】 浙江大学 ， 环境工程， 2008， 博士

【摘要】 当前,中国等发展中国家正成为全球电子电器废弃物的处置中心。原始粗放的拆解方式导致这些地区的土壤环境遭受多种重金属、有机物的严重污染,是研究土壤复合污染的极好案例。单纯依靠对少数已知污染物的浓度分析,已不能满足全面诊断土壤污染及评价土壤健康状况的要求。本研究以我国典型电子电器废弃物拆解地区土壤为研究对象,尝试建立“化学分析—成组生物测试/生物标志物/生态毒性测试”的土壤污染生态毒理诊断技术体系,研究成果主要包括:采用化学测试方法对278km~2区域表层土壤样品进行典型污染物浓度分析。结果表明,研究区域土壤已经受到重金属及有毒有机物的严重污染,甄选出优先重金属污染物Cd、Cu及Zn、Hg,有机污染物PCBs、PCDD/Fs、PAHs。源解析表明与不当拆解直接相关,地统计分析表明污染物存在扩散趋势。对土壤的生物急性毒性效应进行研究,结果表明,拆解地区土壤对植物、土壤无脊椎动物、微生物具有显著的急性毒性效应。白菜根伸长抑制、蚯蚓体重抑制均与土壤Cu污染相关。基于不同溶剂温和提取的淡水发光菌方法可以有效检测土壤不同极性污染物的急性毒性,评价污染物的迁移风险。微生物-植物-无脊椎动物的成组急性毒性检测体系可以更为全面诊断土壤急性毒性效应。离体EROD筛选结果表明拆解区土壤具有很高的芳烃受体效应。生物检测与化学分析结合的方法对芳烃受体效应的贡献物进行甄选发现,拆解点附近土壤芳烃受体效应的主要贡献物是PCBs,而拆解区一般农田土壤中芳烃受体效应则由PCDD/Fs、PCBs与PAHs共同贡献。特异生物标志物结合化学检测的方法可以较好诊断土壤芳烃类污染。离体SOS/umu测试筛选结果表明拆解区土壤具有较高的遗传毒性效应,蚯蚓活体彗星试验、蚕豆根尖微核试验进一步验证了结果。PCBs可能是土壤疏水性组分遗传毒性的主要贡献者,而蚯蚓活体暴露遗传毒性效应的主要胁迫因子可能为Cd。微生物-植物-无脊椎动物的遗传毒性检测体系可以更为全面诊断土壤遗传毒性效应。以上结果表明,所构建的土壤污染生态毒理诊断技术体系可以有效地评价土壤复合污染及土壤整体健康质量状况。更多还原

【Abstract】 Developing countries such as China face a rapidly increasing amount of imported Waste Electrical and Electronic Equipment (WEEE) or electronic and electric waste (e-waste), which is from developed countries for recycling. Unregulated salvaging operations have resulted in severe contamination of toxic metals and organic chemicals for soil in these areas, which turned to be a great study case on soil complex pollution. However, instrumental analysis can provide little information on the biological effects and can not evaluate the complex contamination and the soil quality very well. This dissertation aimed to develop methods of ecological toxicological diagnosis of contaminated soil from a typical e-waste recycling center in Zhejiang province in China. The main results are summarized as follows.The concentrations of toxic metals including Cu, Zn, Pb, Cr, Cd, As, Hg, and organic pollutants including PCDD/Fs, PCBs and PAHs were determined in about 300 soil samples from the e-waste recycling center, which covers 278 km~2. It was indicated that Cd, Cu, Hg, Zn, PCBs, PCDD/Fs and PAHs were the contaminants which should be preferentially controlled. The sources of these pollutants were identified as rude dismantling of e-waste. And spatial distributions of the contaminants were geo-statistically analyzed, which indicated the wide spread of pollution in this area.The acute toxicities of the soil samples were determined by using seed germination assay, root elongation test, earthworm lethal assay, earthworm weight inhibition test and luminescent bacterium bioassay. The results indicated that the soils in the study area have acute toxicities to plant, earthworm and microorganism. These toxicities had correlations with the contaminations of Cu. The luminescent assay using fresh water microorganism based on different solvents mild extraction is valuable to assess the acute toxicities of soluble and hydrophobic contaminants in soil, and the risk to groundwater. The eco-toxicological diagnosis system for acute toxicity evaluation is helpful to valuate the soil pollution and soil quality.The significant AhR effect of soil from the e-waste recycling area was detected using in vitro EROD bioassay. The prevalent contributor of effect was identified as PCBs near e-waste recycling sites by combining of chemical analysis and bioassay. However, in the cropland soil which was not polluted directly in the recycling area, the main contributors were PCDD/Fs, PCBs and PAHs. The combination of bioassay and chemical analysis is useful to identify the contamination of dioxin-like compounds.Finally, the comet assay, micronucleus test and SOS/umu test were performed to evaluate the genotoxicity of soil by using organisms from multiple trophic levels. It was indicated that the soil was genotoxic to microorganism, soil invertebrate, and plant. The contributors of genotoxicities were considered as PCBs and Cd. The genotoxicity of soil could be better evaluated when using a battery of bioassays.The methodologies of ecological toxicological diagnosis were proved to be valuable to access the soil complex contamination and soil quality.更多还原