Distribution And Sources Of PAHs In Surface Soils In Different Functional Areas Of ShaanXi Province

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organicpollutants (POPs) that widespread in the environments. PAHs are mainly originatedfrom incomplete combustion of fossil fuel and biomass. The environmental pollutionand fate of PAHs have become a hot research topic in the environmental sciencedomain.Based on the present situation of PAH studies in ShaanXi Province, in this paper,thirty-one surface soil samples were collected from five functional areas in ShaanxiProvince in October,2012. Sixteen priority polycyclic aromatic hydrocarbons (PAHs)were quantified using gas chromatograph-mass spectrometer (GC-MS). The resultsshowed that the total concentration of PAHs in surface soils ranged from7.27ng/g to589.43ng/g with a mean value of132.73ng/g in Shaanxi Province. The lowestconcentration of PAHs was found in the area of Cuihua Mountain; meanwhile thehighest concentration was found in the Heping industrial park of Xi’an, indicating thedifferent pollution sources. The order of the concentration of PAHs in the five functionalareas was: industrial area> downtown> suburbs> rural area> background. In addition,the main component of PAHs in soil samples of the study area was mainly formed byhigh molecular weight hydrocarbons. Specifically, the PAHs content in soil ranged asfollows：four-ring>six-ring>five-ring>two-ring> three-ring．By comparison with thePAHs concentrations in other typical regions in China and foreign countries, it indicatedthat the PAHs pollution in surface soils in five functional areas of Shaanxi Province wasnot relatively serious． According to European soil environmental evaluation criteria,77.4%of the soilsamples were classified as not polluted, and the remaining soil samples were classifiedas slightly polluted. Ratio method was applied to investigate the sources of PAHs in thisstudy. The results indicated that PAHs in the surface soils of Shaanxi Province may beoriginated from a mixture of combustion source and petroleum source. And the resultsof PAHs source apportionment were consistent with energy consumption structure ofShaanxi Province.The results of this study would provide a scientific basis for the development ofrelevant policies and add new contribution to the Stockholm Convention for ShaanXiProvince.