State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China; Department of International Environmental and Agricultural Science (IEAS), Tokyo University of Agriculture and Technology (TUAT), 3-5-8, Saiwai-cho, Fuchu Tokyo 1838509, Japan.
Centre for Environmental Sciences, Central University of South Bihar, BIT Campus, Patna 800014, Bihar, India.
Ecotoxicol Environ Saf. 2017 Oct;144:498-506. doi: 10.1016/j.ecoenv.2017.06.057. Epub 2017 Jul 1.
Regardless of the ban on the polychlorinated biphenyls (PCBs) decade ago, significant measures of PCBs are still transmitted from essential sources in cities and are all inclusive ecological contaminants around the world. In this study, the concentrations of PCBs in soil, the air-soil exchange of PCBs, and the soil-air partitioning coefficient (K) of PCBs were investigated in four noteworthy urban areas in Nepal. Overall, the concentrations of ∑PCBs ranged from 10 to 59.4ng/g dry weight; dw (mean 12.2ng/g ±11.2ng/g dw). The hexa-CBs (22-31%) was most dominant among several PCB-homologues, followed by tetra-CBs (20-29%), hepta-CBs (12-21%), penta-CBs (15-17%) and tri-CBs (9-19%). The sources of elevated level of PCBs discharge in Nepalese soil was identified as emission from transformer oil, lubricants, breaker oil, cutting oil and paints, and cable insulation. Slightly strong correlation of PCBs with TOC than BC demonstrated that amorphous organic matter (AOM) assumes a more critical part in holding of PCBs than BC in Nepalese soil. The fugacity fraction (ff) results indicated the soil being the source of PCB in air through volatilization and net transport from soil to air. The soil-air partitioning coefficient study suggests the absorption by soil organic matter control soil-air partitioning of PCBs. Slightly weak but positive correlation of measured Log K with Log K (R = 0.483) and Log K (R = 0.438) suggests that both Log K and Log K can predict soil-air partitioning to lesser extent for PCBs.
尽管十年前已禁止多氯联苯 (PCBs)，但城市中仍有重要的 PCB 来源，并且它们是全球范围内无处不在的生态污染物。本研究调查了尼泊尔四个重要城市地区的土壤中 PCB 浓度、PCB 的气-土交换以及 PCB 的土壤-空气分配系数 (K)。总体而言，∑PCBs 的浓度范围为 10 至 59.4ng/g 干重；dw（平均值为 12.2ng/g ±11.2ng/g dw）。在几种 PCB 同系物中，六氯（22-31%）最为突出，其次是四氯（20-29%）、七氯（12-21%）、五氯（15-17%）和三氯（9-19%）。尼泊尔土壤中 PCB 排放量增加的来源被确定为变压器油、润滑剂、断路器油、切削油和油漆以及电缆绝缘材料的排放。PCBs 与 TOC 的相关性略强于 BC，这表明无定形有机物质 (AOM) 在保持 Nepalese 土壤中 PCBs 方面比 BC 更为重要。逸度分数 (ff) 的结果表明，土壤通过挥发和从土壤到空气的净传输成为空气中 PCB 的来源。土壤-空气分配系数研究表明，土壤有机质的吸收控制了 PCBs 的土壤-空气分配。实测 Log K 与 Log K（R = 0.483）和 Log K（R = 0.438）之间的弱正相关表明，Log K 和 Log K 都可以在较小程度上预测 PCBs 的土壤-空气分配。
