Use of Column Leaching Test to Study the Leachibility of Polycyclic Aromatic Hydrocarbons from Contaminated Soil

Document Type : Original Articles


1 Department of Environmental Engineering, Faculty of Environment, University of Tehran, Tehran.

2 Department of Environmental Pollution, Environmental Sciences Research Institute, Shahid Beheshti University, G.C.


Column leaching tests become increasingly important for assessing the risk of release of pollutants from soil into water. In this study a column leaching test was designed to provide insight into the fate of selected PAHs in soils and their leaching behavior. Two columns (columns 1 and 2) were prepared based on a standard procedure in which 5 and 20 percent of contaminated soil were used, respectively. The percolates were collected at specified L/S ratios. Results showed relatively high initial concentrations of flourene, fluoranthene and benzo(a)anthracene for column 2. Released amounts of PAH compounds were decreasing with increasing molecular size, or rather the hydrophobicity of the compound. The effect of dissolved organic carbon on PAHs leaching was also investigated in this research. Approximately 2.45% and 0.67% of the total initial amounts of studied PAHs in the soil was leached in columns 1 and 2, respectively. Results showed that high PAHs concentration in the solid phase does not necessarily imply serious groundwater contamination risk during a leaching event (e.g. rain fall) and significant amount of contaminants may stay in the soil layer for a long time and do not leach down into groundwater.