Effect of soil solids concentration in batch tests on the partition coefficients of organic pollutants in landfill liner-soil materials

Abstract

The effect of the soil solids concentration in batch tests on the measured values of the partition coefficient (Kp) of organic pollutants in landfill liner-soil material was investigated. Since this study was based on the results of batch and column tests conducted independently, there were limitations to the conclusions derived. The organic compounds tested were benzene, methylene chloride, toluene, trichloroethylene, and p-xylene. The results of this study showed that as soil solids concentrations increased, the measured Kp values of these organic compounds strongly decreased. The observed values of Kp stabilized when the soil solids concentration was above a certain value. Typical Kp values obtained from batch tests conducted under high soil solids concentrations were close to those obtained from column tests. It was concluded that the Kp values of organic compounds measured under low soil solids concentrations, i.e., less than 100 g/l, may not correctly simulate the field situation. Consequently, the values of Kp obtained with low soil solids concentrations can result in an overestimation of the retardation factor of the landfill liner material.