电子垃圾拆解地周边土壤中二(口恶)英和二(口恶)英类多氯联苯的浓度水平

采集了电子垃圾拆解地周边125个点位的151个土壤样品,分析了土壤中4~8氯代二噁英和二噁英类多氯联苯的浓度.表层土壤样品中总二噁英的浓度范围为280~7 010 pg·g-1,平均浓度为1 380 pg·g-1.中层和深层土壤样品中总二噁英的平均浓度分别为表土的63%和38%.表土样品中二噁英毒性当量浓度(以I-TEQ计)范围为1.4~94.8 pg·g-1.根据德国关于毒性当量浓度的指导方针,125个土壤样品中只有19个(15%)可以被认为对人体健康无害,其余85%的土壤需要调查二噁英的来源.如果考虑多氯联苯对毒性当量的贡献,则有98%的土壤需要调查二噁英的来源.主因子分析被用来调查这一地区二噁英的排放源.通过对土壤中二噁英的同系物分布进行分析,发现拆解活动是这一地区热过程二噁英的主要排放源,也是这一地区土壤中二噁英的主要来源.

Levels of PCDD/Fs and Dioxin-Like PCBs in Soils Near E-Waste Dismantling Sites

One hundred and fifty one soil samples from 125 sampling points were collected near E-waste dismantling sites and analyzed for polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs). Total concentration of PCDD/Fs in topsoil samples ranged from 280 pg·g^-1 to 7010 pg·g^-1 dry weight with the mean value of 1380 pg·g^-1 dry weight. The mean value of the second layer and the deepest layer is 63% and 38% of that of top soils, respectively. The toxic equivalent quantity (TEQ) of PCDD/Fs in top soils ranged from 1.4 pg·g^-1 to 94.8 pg·g^-1(I-TEQ). According to the guidelines for TEQ concentrations established in Germany, 19 of 125 topsoil samples (15% of the total topsoil samples analyzed) could not be expected to pose human health hazards. The rest of 85% of top soils needs investigations of source identification. If the contribution of PCB to TEQ was considered, 98% of top soils need investigations of source identification. Principle component analysis (PCA) is used to identify the PCDD/Fs sources. The homologue profiles of PCDD/Fs showed that dismantling activities are the main emission resources of the PCDD/Fs from thermal processes, also are the main emission resources of the PCDD/Fs in soils of this area.