A Study On The Distribution Of Organic Pollutants And Its Influence Factors At A Typical Petrochemical Contaminated Site

Petroleum pollutants not only residue in aeration zone, but also possibly enter into groundwater aquifer. Due to they are insoluble in water, and hardly degraded by nature, only part of them are transferred, removed and absorbed by degradation and volatilization, most of them still residue in the environment for several years. They pollute soil and groundwater resources, damage ecological environment system and threaten human health. So mastering migration and transformation law of petroleum pollutants in aeration zone is important to environment protection.This article discussed the distribution of petroleum contaminants in the unsaturated zone in the studied area. Site investigation and testing of soil samples were carried out to investigate the influence factors of petroleum contaminants. The results show that VOCs are main pollutants, especially benzene series and chlorinated hydrocarbon. The distribution of pollutants is influenced by sources, soil lithology, organic carbon, water content, porosity and water level. The most important factor influencing the vertical distribution and migration of Dichloromethane is water content, while the most important factor influencing the vertical distribution and migration of Bromodichloromethane is porosity. Toluene is enriched in soil with higher content of organic carbon and water content. Factors influencing the vertical distribution and migration of 1,1,2-trichloroethane is porosity and organic carbon. Traditional microbiology method reveals that total number of bacterial count and denitrifying bacteria show similar changes with organic pollutants concentration.Bacteria number is much more where has abundant organic carbon, high soil permeability and high water content. The main effects of biodegradation of organic pollutants are denitrification and iron reduction under natural conditions.