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Using Concentrations of Methane and Gasoline Hydrocarbons in Soil Gas to Predict Vapor Intrusion of Benzene
Citation:
WILSON, J. T. AND K. JEWELL. Using Concentrations of Methane and Gasoline Hydrocarbons in Soil Gas to Predict Vapor Intrusion of Benzene. Presented at 2011 EPA Region 3 LUST Technical Workshop , Rehoboth Beach, DE, September 28 - 30, 2011.
Impact/Purpose:
Poster for the 2011 EPA Region 3 LUST Technical Workshop in Rehoboth Beach, DE (September 28, 2011)
Description:
Risk management of petroleum vapor intrusion has been a daunting and challenging task for the Underground Storage Tank Program. Because chlorinated solvents do not degrade in soil gas, techniques that focus on their properties and behavior can produce useful estimates. However, techniques and approaches (such as the J&E model) that have been successfully applied to evaluate the risk from chlorinated solvents can grossly overestimate the risk from petroleum hydrocarbons. Because petroleum hydrocarbons are biologically degraded in soil gas, there is no chance that any technique that focuses solely on their properties and behavior can produce useful estimates. The rate and extent of biodegradation is controlled by the supply of molecular oxygen, which in turn is limited by competing demands for biodegradation of methane and gaseous alkanes in soil gas, in addition to the demand provided by the contaminant of concern. New approaches are coming forth that describe the behavior of petroleum constituents in a comprehensive biogeochemical and spatial context.