Abstract: In order to understand the fate of PAHs and heavy metals in soil-plant system,the behaviors of PAHs and heavy metals in soil of land treartment system (LTS) at western Shenyang were studied.PAHs and heavy metals are accumulated in0-20cm soil layer, and can not be found below.The PAHs content is decreased from April to October, which shows that soil microbes play an important role in the degradation of PAHs, and the degradation rate is related to ecojogical structure of soil-plant system.Phenanthrene can be determined with a high concentration in the groundwater, which indicates the possibility of its migration downward.Willow can reduce and purify heavy metals.This study shows that strict control of pollutant load of PAHs and heavy metals in wastewater and rational design of ecological structure are the key points for avoiding the accumulation of PAHs and heavy metals in soil.

Key words: Wastewater, Land treatment system, Polycyclic aromatic hydrocarbons (PAHs), Heavy metal, Soil, Accumulation and degradation, diameter class length distribution, soil warming, nitrogen addition, extreme value model.