ABSTRACT
Petroleum products are complex mixtures of hydrocarbons with widely varying physical-chemical properties. A petroleum product can migrate through soil as a separate immiscible phase until it is completely redistributed in the vadose zone or until it reaches the water table. Redistribution is controlled by the volume of the petroleum product spill, the viscosity of the petroleum product, the characteristics of the soil, and the depth to the water table. The need to evaluate potential environmental and human health impacts has prompted risk analysts to use chemical transport and fate models to predict the potential environmental behavior of petroleum products in soil. The user can specify cleanup levels for soil, the impervious surface, vegetation, or any combination of the three. The advantage of this strategy is that the behavior of the petroleum product can be evaluated with a single model simulation. A model run would be conducted for each component group assuming the remainder of the mixture was not present.
