ABSTRACT
Following the removal of the contaminant source, in situ remediation of soils contaminated with hydrophobic compounds involves the containment and treatment of the subsequently contaminated groundwater as well as the soil itself. Slightly soluble or immiscible contaminants in soils may be slowly solubilized or suspended in groundwater above drinking water limits and thus present long-lasting threats to human health. Nonaqueous phase liquids (NAPLs) are hydrophobic organic compounds that are slightly soluble or immiscible in water. Migration and infiltration of NAPLs at a site are a function of interactions of contaminant phases, site-specific conditions, and forces in the soil/water matrix. Selection of the most effective surfactant for p-t enhancement is a function of site-specific conditions. The physical/chemical characteristics of the site contaminant, groundwater quality, geology, and hydrogeology must be matched with the characteristics of the 12,000 commercially available surfactants. The nature of the hydrophilic head group determines the classification and behavior of surfactants.
