Sorption of selected polycyclic aromatic hydrocarbons on soils in oil-contaminated systems

The adsorption and desorption behaviour of selected polycyclic aromatic hydrocarbons (PAHs) on different soils was investigated by static and dynamic methods. On the basis of a system including the four phases of soil, water, oil adsorbed and oil in emulsion, a model for the description of the adsorption behaviour in the presence of oil was developed. In systems without oil a similar partitioning behaviour in the batch and column experiments was observed for all PAHs. Thus the distribution coefficients can be calculated from the octanol/water coefficient of the aromatic compounds and the organic carbon content of the soils. The presence of a lipophilic phase had a significant influence on the sorption of the PAHs, usually resulting in a drastic decrease of adsorption with increasing oil content in the system. For the oil-contaminated system the modelling of the adsorption behaviour enabled a more detailed interpretation of the experimental observations as well as the calculation of the sorption behaviour for the PAHs from characteristic parameters of the components involved. (C) 2000 Elsevier Science Ltd. All rights reserved.