Characteristics Of Polycyclic Aromatic Hydrocarbons Distribution And Its Influence Factors In Soil In Shanxi Province,China

Polycyclic aromatic hydrocarbons(PAHs)are one of the earliest carcinogens discovered and studied in the world,and the number of them is the most among carcinogens.As persistent organic pollutants(POPs),PAHs in the environment are difficult to degrade and there are more opportunities to endanger the ecological environment and human health.In this study,166 surface soil samples were collected in Shanxi Province in May 2015.16 priority PAHs were analyzed by gas chromatograph-mass spectrometer(GCMS),and their spatial distribution,sources and potential health risks were discussed.The results could provide basis for soil quality improvement in Shanxi Province.The main conclusions were as follows:(1)The total concentrations of 16 priority PAHs(?16PAHs)in soil ranged from 33.44 to 6766.4 ng/g(median: 175.55 ng/g,mean: 295.44 ng/g).4-ring PAHs were the main components in soils,followed by 5-ring,3-ring,6-ring and 2-ring PAHs.Compared with other cities at home and abroad,the PAHs pollution in soils of Taiyuan,Linfen and Changzhi was at medium level.(2)The hot spot areas of agriculture soil pollution were mainly concentrated in the central and southern areas of Shanxi Province,and the content of 16 PAHs in the northern soil was lower.The spatial distribution of PAHs is greatly affected by industrial activities and motor vehicles.(3)The diagnostic ratios of PAHs indicated that PAHs in soils were primarily derived from coal/biomass burning,while there were also some petroleum combustion sources.The results of principle component analysis combined with multiple linear regression model showed that the contribution rates of the three sources were 72.64% for coal combustion and vehicle emission,17.20% for coking,and 10.16% for biomass burning,respectively.According to the result of positive matrix factorization(PMF),four sources were identified: coal combustion(42.98%),biomass burning(10.68%),coking(18.96%),and vehicle emission(27.38%).(4)The mean toxic equivalent concentration of PAHs in soil of Shanxi Province was 30.81 ng/g(range from 2.20 to 974.89 ng/g),which was at medium level in the world.Vehicle source and coal combustion source were the most important contributors to the toxic equivalent concentration.The results of health risk assessment showed that there was potential risk of cancer in all soil of ShanxiProvince,which should be paid more attention.