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

Abstract

The purpose of this research was to quantify the effects of water content (0.3 to 0.75% for sand, and 0.4 to 1.25% for silt-clay) and temperature (4 to 40 °C) on the equilibrium distribution of the priority pollutants, dichloromethane and 1,1,1-trichloroethane in dry Korean decomposed granite soil. The values of effective partition coefficient (K _eff) were largely decreased as the water content increased. Organic pollutant partitioning in dry soil is composed of both water saturated site and dry site in sorbent, and dry site which has high partition coefficient, is reduced as the water content increases. As the temperature increased, the K _eff values decreased, and this effect was magnified at lower water contents. The values of K _eff were correlated better with the estimated values using proposed model. Therefore, in the analysis of distribution and transport of pollutant in unsaturated soil, the effects of water content and temperature on the partitioning should be considered.