Laboratory for Earth Surface Processes, College of Urban and Environmental Sciences, Peking University, Beijing, China.
Environ Toxicol Chem. 2012 Oct;31(10):2246-52. doi: 10.1002/etc.1959. Epub 2012 Aug 24.
The spatial variation in concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) in surface soils in the North China Plain and the influential factors were examined in the present study. High concentrations of the sum of 16 PAHs (∑PAH(16) ) appeared in cities and their surrounding areas. Emissions and soil organic carbon (SOC) content significantly regulated spatial differentiation of PAH contamination in soils in the study area. Compared with emissions, concentrations of individual and total PAHs in soils were more closely controlled by the SOC content. Furthermore, concentrations of PAH species with lower molecular weight (e.g., two- or three-ring) in surface soils were more strongly correlated with the SOC content in comparison with those of higher molecular weight (e.g., five- or six-ring), mainly because of their higher saturated vapor pressure, thus higher mobility. The spatial variation of PAH species in soils in the North China Plain tended to be larger with increasing benzene ring numbers, and the difference in physicochemical properties of PAH species determined their distinct spatial distribution characteristics. The present study highlights the relative importance of emissions and SOC content in spatial variation of PAHs and the dependence of the spatial distribution characteristics of PAH species in surface soils on their physicochemical properties at a regional scale. Results of the present work are helpful for regional risk assessment of the contaminants tested.
本研究考察了中国北方平原表层土壤中 16 种多环芳烃（PAHs）浓度的空间变异及其影响因素。∑PAH（16）的浓度在城市及其周边地区较高。排放和土壤有机碳（SOC）含量显著调节了研究区土壤中 PAH 污染的空间分异。与排放相比，土壤中各单体和总多环芳烃的浓度受 SOC 含量的控制更为密切。此外，与高分子量（如五环或六环）的 PAH 相比，低分子量（如二环或三环）的 PAH 种类在表层土壤中的浓度与 SOC 含量的相关性更强，主要是因为它们具有较高的饱和蒸气压，因此具有较高的迁移性。中国北方平原土壤中 PAH 种类的空间变异随着苯环数的增加而趋于增大，PAH 种类的物理化学性质差异决定了它们的独特空间分布特征。本研究强调了排放和 SOC 含量在 PAHs 空间变异中的相对重要性，以及表层土壤中 PAH 种类的空间分布特征对其物理化学性质的依赖性在区域尺度上。本研究结果有助于对所测试污染物的区域风险评估。
