中文摘要：

为了解多环芳烃在土壤中的迁移,研究了慈溪市农田表层土壤（耕层）和亚表层（犁底层）土壤中15种PAHs的含量及分布特征.表层土壤中PAHs的总量在70.4-325.1μg·kg^-1之间;含量较高的几种化合物为萘（Nap）、菲（Phe）、荧蒽（Fla）、芘（pyr）和（chr）等,但主要以4环以上芳烃为主;Fla/（Fla＋Pyr）与IcP/（IcP＋BgP）比值分析表明,表层土壤中的PAHs主要来源于草、木、煤等的燃烧和汽车尾气排放.亚表层土壤中,PAHs总量为29.5-232.3μg·kg^-1，以2环加3环化合物为主,单体PAH含量与表层土壤中含量的比值与其辛醇-水分配系数（logKow）显著相关（r=0.923,p〈0.0001）,说明亚表层土壤中PAH主要来源于表层土壤的淋溶,根据化合物的logKow值可预测其在土壤中的迁移情况.亚表层土壤中PAHs的含量与有机质的含量极显著相关（r=0.945,p〈0.0001）,但表层中二者则无显著相关性（p=0.0887）,表明耕作措施可能会对PAH在表层土壤中的分布产生影响.

英文摘要：

Samples of surface and subsurface layers of arable soils in Cixi County were collected and 15 polycyclic aromatic hydrocarbons （PAHs） in the samples were determined by HPLC with a fluorescence detector. The results show that the total PAHs in the surface soils ranged from 70.4 to 325. 1μg·kg^-1, dominated by the large molecular weight PAHs with 4 or more aromatic rings. Nap, Phe, Fla, and Pyr were present at relatively high levels. The ratios of Fla/（ Fla ＋ pyr） and IcP/（ IcP ＋ BgP） indicate that the PAHs in the surface soils are probably originated from the combustion of grass, wood, and coal, and vehicle exhaust. In the subsurface soils, the total PAHs varied from 29.5 to 232.3μg·kg^-1, with 2-ring, and 3-ring PAHs as the predominant compounds. The concentration ratios of individual PAH between the surface soils and the sub-surface soils are significantly correlated with the octanol-water partition coefficient （ logKow）, indicating that PAHs in the subsurface soils are mainly leached from the upper soils. Transport of each individual PAH in soils may be predicted according to its logKow value. PAHs contents in the subsurface soils are significantly correlated with soil organic matter contents （r = 0. 836, p 〈 0. 0001 ）, but not for the surface soils. This suggests that agricultural management may influence the distribution of PAHs in the surface soils.