Soil interactions with petroleum hydrocarbons: Abiotic processes

Soil and groundwater resources in many parts of the world are threatened by spilled petroleum products. These products generally consist of complex mixtures of volatile hydrocarbons with different vapor pressures. The volatilization of light hydrocarbon fractions leads to changes in viscosity and density of the residual nonaqueous liquid. This may cause changes in the transport characteristics of the porous matrix and of the residual liquid. Differing volatilization and solubility characteristics result in differential distribution of released hydrocarbon components in air, soil, and water environmental compartments. Soil frequently serves as the site of petroleum spills and hence the capacity of the soil to filter, retain, or release hydrocarbons is fundamental in determining the type and extent of environmental contamination. Retention, volatilization, and transport of hydrocarbons as affected by soil physical and chemical properties is reviewed.