Composition, source and potential risk of polycyclic aromatic hydrocarbons (PAHs) in vegetable soil from the suburbs of Xianyang City, Northwest China: a case study

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental contaminants. In this study, 16 priority PAHs of United States Environmental Protection Agency (US EPA) in vegetable soil from the suburbs of Xianyang City, Northwest China were investigated. The total concentration of 16 PAHs (P16PAHs) ranged from 16.68 to 1938.33 mu g kg(-1), with a mean of 210.31 +/- 379.43 mu g kg(-1). PAHs of vegetable soil were mainly dominated by high molecular weight PAHs with four benzene rings (i. e., BbF and Chy). Diagnostic ratios, principal component analysis (PCA) and cluster analysis (CA) showed that PAHs of vegetable soil mainly originated from combustion of petroleum (e. g., liquid fossil fuel, vehicle and crude oil, 59.02 %) and coal (21.65 %). P16PAHs in 24 % soil samples were higher than 200 mu g kg(-1), suggesting a light to heavy pollution. Toxic equivalency quantity (TEQ) for seven carcinogenic PAHs (i. e., BaA, Chy, BbF, BkF, BaP, DBA and InP) in all soil samples were below the safe level of 600 lg kg(-1). Likewise, TEQ of 10 PAHs (i. e., NaP, Phe, Ant, Fla, BaA, Chy, BkF, BaA, BghiP and InP) in eight soil samples exceeded Dutch Target Values of Soil Quality (32.96 mu g kg(-1)). Therefore, exposure to these soils through various paths could be regarded as a potential health hazard.