典型污灌区土壤中多环芳烃的垂直分布特征

研究了有污水灌溉历史的沈抚灌区、浑浦灌区和清原对照点3个土壤剖面多环芳烃(PAHs)含量的分布特征.结果表明,在美国EPA优先控制的16种PAHs中,沈抚灌区土壤剖面中检测出10种,浑浦灌区检出12种,清原检出8种.PAHs总含量峰值随着土壤深度的增加呈下降趋势,但最高值均未出现在0～2 cm土层,而是分布在2～5和5～10 cm土层.各剖面单组分分布以4～5环PAHs为主,主要污染物是荧蒽、苯并a]蒽和苯并k]荧蒽,低环PAHs含量峰值多集中在0～2 cm土层,中、高环PAHs大部分分布在5～10 cm土层.从单组分比值和母体多环芳烃比值可以看出,3个剖面的PAHs污染源来自于汽油、原油、煤的不完全燃烧,或通过污水灌溉,或以烟尘颗粒为载体通过大气干、湿沉降和风力输送进入到土壤环境中. 

Vertical Distribution Characteristics of Polycyclic Aromatic Hydrocarbon in Typical Wastewater Irrigated Soils

Vertical distribution of polycyclic aromatic hydrocarbons(PAHs) in Hunpu and Shenfu wastewater irrigated soil and Qingyuan soil(control site) was discussed.The qualitative results demonstrated that 10 kinds of EPA priority PAHs were detected in Shenfu,while 12 kinds of the PAHs in Hunpu and 8 kinds of the compounds in Qingyuan are detected.The total concentration of PAHs was found to have peak at(2～5) and 5～10 cm layer and decline with depth.Four-ring and five-ring PAHs had a high proportion in each profile.The principal PAHs compounds were fluoranthene,benzoa]anthracene and benzok]fluoranthene which was similar with surface soil.The highest concentration of low-ring compounds distributed at 0～2 cm,and the others at 5～10 cm.PAHs ratios inferring the sources of PAHs indicated that the main sources of PAHs in the soils were incomplete combustion of petrol,crude soil and coal as well as the contribution of wastewater irrigation.