| In dealing with health risk of PCBs Exposure via the soil-vegetable pathway at site-specific Taizhou, residues of PCBs in background soils from North Zhejiang were investigated,and the distribution and accumulation of PCB congeners PCBs in soils and vegetables from Taizhou were studied. On the basic of these investigations, health risk of PCBs exposure via the soil-vegetable pathway in Taizhou were assessed.The study will helpful for the remediation of PCBs pollution in high-contaminated area .The main results obtained from the study are concluded as follows:(1) Residues of PCBs congeners in agriculture soils of North ZhejiangChoose North Zhejiang ,a primary production base of agricultural products ,asnon-contaminated area. 66 soil samples from the three towns of Pinghu,Haiyan and Tongxiang were investigated.The results show that the concentration of PCBs in these surficial soils was 0-17.30 ng/g.The mean concentration is 3.99 ng/g.PCB44 and PCB138 is the highest, 0.95 ng/g and 0.53 ng/g respectively. PCBs in subsurficial soils is 0-7.18ng/g. The mean of them is 2.72 ng/g .Higher leverl of PCBs in surficial soils is found than subsurficial ones. Soil type is a significant factor for the difference of vertical distribution of PCB congeners.The congeners of PCBs in all surficial and subsurficial paddy soils is characterized by 4-7CB. PCBs in surficial vegetable soils is also characterized by 4-7CB.But in subsurficial vegetable soils, the fraction of lower chlorinated PCBs was increased ,the higher reduced.(2) The contaminated characteration of PCBs in soil and vegetable at TaizhouPCB congeners in plants, bulk soils and rhizosphere soils from Taizhou wereinvestigated.The results show: The concentration ofΣ13PCBs in bulk soils is 8.45-22.51 ng/g, which is higher than that of North Zhejiang, a Non-contaminated area. The concentration of PCBs in rhizosphere soils is 17.90-41.11 ng/g and higher than that in bulk soils. The concentration ofΣ13PCBs in leaf, stem and root is 285.93-609.65 ng/g, 41.78-112.11 ng/g, 75.12-282 ng/g respectively. The order of the concentration ofΣ13PCBs and PCB congeners in different tissues of plants is leaf> root > stem. Consequently, the possible sources of PCBs in plants are presumed: Atmosphere deposition is the main pathway of PCBs contamination of leaf. PCBs of root are from rhizosphere soil. In this paper, a further study shows: the concentrations of PCB congeners in different tissues are different with each other. The congeners of PCBs in leaf is characterized by 3-5CB, while 5,6CB are dominant among the congeners of PCBs in root; Soil-root bioconcentration factors (BCFs) decreased with increasing log Kow for PCBs.(3) Health risk assessment of PCBs exposure to vegetables from E-waste inTaizhouChoose greengrocery and cabbage for health risk assessment. Use the technology of EPA(1996) to assess health risk of PCBs exposure. PCB contamination levels of vegetables in the surroundings of E-waste contamination areas were investigated and the risks to human health were evaluated in Taizhou. Investigation results showed the average PCB concentrations were 5.98-130.70μg/kg while there were high accumulation of some vegetable samples. The health risk assessment of PCBs exposure via the soil-vegetable pathway resulted in lifetime cancer risk estimates on the order of 3.6×10-5～7.8×10-4, which accessed baseline level of lifetime carcinogenic risk. The non-carcinogenic risk level of all vegetable samples were higher than the acceptable risk level (HQ=1). PCBs contamination of some common vegetables was confirmed, which had caused a major risk to human health.
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