Effects of water content and temperature on equilibrium distribution of organic pollutants in unsaturated soil

Abstract

The purpose of this research is to quantify the effects of water content (0.3-1.25\%) adn temperature (4-40$^\circ$C) on the equilibrium distribution of toxic organic pollutant in unsaturated soil. The priority pollutants, Dichloromethane and 1,1,1-Trichloroethane are selected as toxic organic pollutants and the Korean decomposed granite soil as the experimental soil media. Two models were developed on the basis of the shapes of the soil water distribution in unsaturated soil and compared; complete surface coating (model I) vs. spot clustering (model II). From the experiment, a large decrease in the values of effective partition coefficient (Keff) was observed as the water content increased. As the temperature increased, the Keff values decreased, and this effect was magnified at lowr water content. The values of Keff were correlated better with the estimated values using model II. Thus it was experimentally proved that the soil water tends to enclose the enclose the soil grain partly at lower water contents.