采用气相色谱质谱联用仪检测了白洋淀表层(0~20 cm)和亚表层(20~30或农田30~40 cm)土壤中16种多环芳烃的含量。结果表明:表层土壤中多环芳烃总量的变化范围为146.0~645.9 ng·g^-1,平均含量为417.4 ng·g^-1;亚表层土壤中多环芳烃总量的变化范围为43.0~394.5 ng·g^-1,平均含量为152.4 ng·g^-1。表层土壤中多环芳烃含量与有机碳含量相关性不显著,亚表层土壤中多环芳烃含量与有机碳含量呈显著正相关(P〈0.01),这可能表明了土壤埋藏改造过程中PAHs与土壤有机相结合程度不断加强,以及土壤中不同环数多环芳烃的环境行为差异,总体上看,与高环(≥4环)多环芳烃相比,萘、菲等低环(2~3环)多环芳烃更容易向下层迁移。PAHs的源解析分析表明,白洋淀表层土壤的多环芳烃表现出显著的以生物质和煤燃烧为主的源特征,这与淀区的人为活动,如秸秆燃烧等相关。
Surface (0-20 cm) and subsurface (20-30 or 30-40 cm) soil samples in Baiyangdian area were collected, and their 16 polycyclic aromatic hydrocarbons (PAHs) contents were determined by GC/MS. The total PAHs contents in surface soils varied from 146.0 to 645.9 ng ·g^-1, with an average of 417.4 ng · g^-1 , and those in subsurface soils varied from 43.0 to 394. 5ng·g^-1 , with an average of 152.4 ng · g^-1 The PAHs contents in surface soils had less correlation with soil total organic carbon (TOC) content, while those in subsurface soils were in adverse, indicating the increasing binding degree of PAHs to TOC in the processes of soil burial and reconstruction, and the differences in the environmental behaviors of different PAHs. In general, low ring (2-3 rings) PAHs such as Nap and Phe transferred from top soil to bottom soil more easily than high ring ( ≥ 4 rings) PAHs. The values of PAHs isomer ratios suggested that biomass and coal combustion were the major sources of PAHs in surface soils of Baiyangdian area, which could be related with the human activities such as straw combustion.