ZHANG Min¹,CAI Wu-tian¹, LIU Xue-song¹, SUN Shan², LI Ming-ze³, WANG Yong-chi¹

(1. Center for Hydrogeology and Environmental Geology, CGS, Baoding 071051, China；
2. China University of Geosciences(Wuhan), CUG, Wuhan 430074, China；
3.Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China)

Abstract：By sampling and analysis of irrigation water, soil and groundwater in a wastewater irrigation area, the distribution characteristics of contaminants in soil and groundwater were studied. The results indicated that the major contaminants are heavy metal Zn, polycyclic aromatic hydrocarbons (PAHs) and pesticide residues HCH in the wastewater irrigation area. The distribution characteristics are different for different contaminants. Heavy metals are mainly accumulated in soil surface, such as Zn , which is mostly accumulated in the arable layer (0-30cm), but it will migrate to deep soil when its concentrations are high enough. According to molecular weight, PAHs can be divided into three categories. In the process of migration, small molecular weight PAHs degrade dramatically; medium molecular weight PAHs can migrate to deep soil and groundwater, and the adsorption capacity is almost the same at different depths; high molecular weight PAHs are stable in chemical property, they can be easily deposited and adsorbed on surface soils and sediments. Pesticide residues HCHs can migrate so deeply as to be 50m at least.

Key words：wastewater irrigation；heavy metal；polycyclic aromatic hydrocarbon PAH；pesticide residue

EARTH AND ENVIRONMENT Vol. 40, No.1, Tot No.287, 2012, Page 30-36