BENZENE AND NAPHTHALENE SORPTION ON SOIL CONTAMINATED WITH HIGH-MOLECULAR-WEIGHT RESIDUAL HYDROCARBONS FROM UNLEADED GASOLINE

For complex nonaqueous phase liquids (NAPLs), the composition of the NAPL retained in the pore space of geologic material weathers until the residual NAPL no longer acts a liquid and exists as discrete regions of hydrocarbon (termed residual hydrocarbons) in association with the geologic media (water wet media), or as thin film coatings on the media (NAPL wet media). In this study, the residual hydrocarbons were found to resist separation from the soil solids even when subjected to shaking in batch reactors. In addition, the magnitude of solute sorption was significantly higher for a low organic carbon soil contaminated with residual hydrocarbons than for natural soil organic carbon.