| Persistent organic pollutants(POPs)produced in industrial activities can accumulate in the soil and cause serious harm to the ecological environment and human health.Traditional analysis method of the determination of Hydrophobic organic pollutants in the environment is general to determinate the total concentration of dissolved concentration and combined concentration,which will overestimate its pollution level,whereas the membrane passive sampling technology based on the determination of the dissolved concentration helps to measure the amount of bioavailable contaminant.This study research on two typical characteristic pollutants:polychlorinated biphenyls(PCBs)and DDTs,using the membrane passive sampling technique to collect and analysis soil samples from Tanggu and Hangu in Tianjin Binhai New Area,to determinate its pollution level,composition and distribution characteristics,and to analyze the sources of PCBs and DDTs pollutants preliminarily with principal component analysis(PCA)and ratio method respectively.The main conclusions are as follows:The concentration range of ?81 PCBs in soil is 3.19?55.66 ng·g-1 and 1.60?37.19 ng·g-1 in Hangu and Tanggu respectively,and the mean concentration is 6.16 ng·g-1 and 5.27 ng·g-1.The concentration range of ?4DDTs in soil is 0?1.67 ng·g-1 and 0?4.07 ng·g-1 in Hangu and Tanggu respectively,and the mean concentration is 0.46ng·g-1 and 0.69ng·g-1.The content of PCBs and DDTs in the soil of the two regions is basically at the same level.The pollution distribution of PCBs is mainly based on Tanggu chemical area and Hangu chemical area and shows a downward trend toward the periphery.Pollution distribution of DDTs:the pollution in Tanggu is in highest level,the northern region in the second level,and the south region is in low pollution level.The area of high pollution level of DDTs in Hangu is in the agricultural land in the north.According to the composition of pollutants,the PCBs in Tanggu and Hanggu soil are mainly low chlorinated biphenyls,mainly including trichlorobiphenyls and tetrachlorobiphenyls,which is consistent with the historical production background of PCBs in China.Among four kinds of typical DDTs isomer and homologue in two area,detection of o,p'-DDT and p,p'-DDD is at the lowest and highest level respectively,and p,p'-DDE is in minimum detection rate.Classification according to different land types of Tanggu PCBs pollution levels are as follows:urban green land>forest land>farmland>garden land>wasteland.Classification according to different land types of Hangu PCBs pollution levels are asfollows:green land>farmland>forest land>garden land>wasteland.The urban green land is located in the central urban area,where there is large traffic flow,and the daily activities of residents will influence the content of PCBs.The pollution of farmland and garden is mainly from the dry and wet deposition of the atmosphere,and the concentration level is low.The pollution level of DDTs in Tanggu is in turn forest land>garden land>urban green area>farmland>wasteland,and it in Hangu in turn is farmland>wasteland>forest land>urban green area.Pesticides used in farmland and garden land are likely to be the new sources of DDTs in the soil.The detection of DDTs in the soil of urban green land,forest land and wasteland is relatively low.Due to principal component analysis,the main source of PCBs in the soil of coastal industrial zone is the industrial production of PCBs in China,and the two chemical regions in Tanggu and Hanggu are the main sources of pollution.In addition,trichlorobiphenyls and tetrachlorobiphenyls which are in highest content and detection rate are mainly redistributed through atmospheric deposition and surface runoff.Due to analysis of DDTs in Tanggu and Hangu soil with ratio method,new sources of pollution are found in both Tanggu and Hangu.The area in high pollution level of DDTs is located in the farmland and garden area of Hangu,which may be derived from the production and use of dicofol. |
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