Characteristics of PAHs in soils under different land-use types and their associated health risks in the northern Taihu Basin, China.

Purpose: Polycyclic aromatic hydrocarbons (PAHs) in the environment are strongly influenced by anthropogenic activities and negatively impact human health. Identifying the sources and potential risks of PAHs in soils will help to prevent soil pollution and utilize land more effectively. Materials and methods: In this study, soils under different land-use types in the northern Taihu Basin were investigated. The PAHs in soils were measured by gas chromatography-mass spectrometry. The toxicity of PAHs from different sources was quantitatively evaluated based on the positive matrix factorization-toxic equivalent quantity (PMF-TEQ) model. The incremental lifetime cancer risk (ILCR) method was used to assess the health risk of PAHs. Results and discussion: The results showed that the Σ₁₆PAHs concentrations varied between 142.26 and 9278.51 ng g^-1, with a mean value of 1640.43 ng g^-1. High molecular weight PAHs were found to account for the largest fractions (87%) of the Σ₁₆PAHs. Significant variation of the PAHs concentrations in soils was observed under different land-use types. The mean concentration of Σ₁₆PAHs in different areas was in the order of industrial area > traffic area > commercial area > residential area > park > farmland. Vehicle emissions and coal/coke combustion were the predominant sources, accounting for 54% and 37% of the Σ₁₆PAHs loading, respectively. The total predicted TEQ of PAHs ranged from 15.71 to 867.35 ng g^-1 (mean 189.29 ng g^-1), and benzo(a)pyrene was the major species. The total ILCR value for soil PAHs exposure was in a range of (0.13 ~ 9.13) × 10^-6. Conclusions: Source identification showed that the dominant source of soil PAHs was vehicle emissions in commercial (89%) and traffic (85%) area, while coal/coke combustion was the main source of soil PAHs in industrial area (43%). The total TEQ indicated a potential carcinogenic risk in the study area, with vehicle emissions and coal/coke combustion making the primary contribution to the total TEQ (95%). The total ILCR value was in a range of 10^-7 ~ 10^-5, which indicated a low health risk. Children experienced a higher cancer risk than adults due to their sensitivity to the carcinogenic effects of PAHs. [ABSTRACT FROM AUTHOR]