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Using Conventional Monitoring Wells to Collect Data Necessary to Understand Petroleum Vapor Intrusion (PVI)
Citation:
Jewell, K., J. Skender, C. Ruybal, AND J. Wilson. Using Conventional Monitoring Wells to Collect Data Necessary to Understand Petroleum Vapor Intrusion (PVI). Presented at 23rd National Tanks Conference and Expo, March 19 - 21, 2012.
Impact/Purpose:
Poster for the 23rd National Tanks Conference and Expo in St. Louis, MO. March 19-21, 2012
Description:
Recent work has clearly established that the possibility for vapor intrusion of petroleum hydrocarbons is greatly reduced by aerobic biodegradation of the hydrocarbons in unsaturated soil. The rate and extent of aerobic biodegradation of benzene (or any other fuel hydrocarbon) in soil gas is controlled by the supply of oxygen. In turn, the supply of oxygen is controlled in part by the oxygen demand of all the degradable components of the soil gas. To understand the aerobic degradation of individual petroleum hydrocarbons, it is necessary to consider the oxygen demand of all the components in soil gas. At present there are two well-established approaches that incorporate the total oxygen demand of hydrocarbons in soil gas into an assessment of petroleum vapor intrusion (PVI). An approach published by Abreu et al. (2009) requires the user to know the total oxygen demand of vapors, expressed as the equivalent concentration of benzene. An approach using the screening model BioVapor requires the user to know the individual concentrations of the hydrocarbons that represent the major portion of the total oxygen demand. This information is almost never collected during typical site characterization at a gasoline spill site. The target compound list for U.S. EPA methods for contaminants in soil gas, such as TO-15, ignores important constituents of soil gas at gasoline spill sites such as methane, butane, and pentane. However, information on the total oxygen demand of vapors can be obtained with a combustible gas meter. These instruments are inexpensive, readily available, and easy to use. This poster reviews the two existing approaches to assess PVI. It presents an approach to use conventional monitoring wells to sample soil gas for analysis in the field with a field meter. It reviews the calculations that transform the data read out from a field meter to a form that is useable with the approach of Abreu et al. (2009)or BioVapor.