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An Approach for Developing Site-Specific Lateral and Vertical Inclusion Zones within which Structures Should be Evaluated for Petroleum Vapor Intrusion due to Releases of Motor Fuel from Underground Storage Tanks
Citation:
Wilson, John T., James W. Weaver, AND H. White. An Approach for Developing Site-Specific Lateral and Vertical Inclusion Zones within which Structures Should be Evaluated for Petroleum Vapor Intrusion due to Releases of Motor Fuel from Underground Storage Tanks. U.S. Environmental Protection Agency, Washington, DC, EPA/600/R-13/047, 2013.
Impact/Purpose:
Ground Water Issue Paper (EPA # will be provided.)
Description:
Buildings may be at risk from Petroleum Vapor Intrusion (PVI) when they overlie petroleum hydrocarbon contamination in the unsaturated zone or dissolved in groundwater. The U.S. EPA Office of Underground Storage Tanks (OUST) is preparing Guidance for Addressing Petroleum Vapor Intrusion at Leaking Underground Storage Tank Sites. The OUST guidance provides general screening criteria that can be used to identify structures that are at risk from PVI. The criteria are used to determine if a structure is included within a lateral or vertical zone where proximity to the contaminant might make the building vulnerable to PVI. If the structure is within a lateral or vertical in inclusion zone, then additional investigation is necessary to evaluate and manage exposure to the vapors. This Issue Paper contains technical suggestions and recommendations proposed by the U.S. EPA Office of Research and Development for applying the criteria provided in the OUST guidance. The Issue paper provides a graphical approach to define a lateral inclusion zone based on the proximity of a structure to the presumed maximum extent of contamination. The presumed maximum extent of contamination is defined by a perimeter of clean monitoring locations that are arranged around the known source of contamination. The lateral inclusion zone is extended past the presumed maximum extent of contamination to allow for uncertainty of the concentrations of contaminants in the space between monitoring locations. The Issue Paper provides instructions and suggestions to use knowledge of ground water flow to refine the lateral exclusion zone, and reduce the area where additional investigation is necessary. The Issue Paper provides recommendations on collecting and analyzing core samples to determine the vertical extent of contamination in the unsaturated zone, and water samples to determine the extent of contamination in ground water. The Issue Paper provides illustrations of the appropriate comparison of the field data to the criteria in the OUST Guidance. In combination, definition of lateral and vertical inclusion zones makes the best use of site characterization data for assessing the risk of PVI to structures at a LUST site. The procedures outlined in this Issue Paper provide a realistic data-driven approach to screen buildings for vulnerability to PVI.
URLs/Downloads:
ORD-003360 CALCULATOR FOR PVI WILSON_JOHN.XLSXEPA600R13047.PDF (PDF, NA pp, 2935.078 KB, about PDF)
http://nepis.epa.gov/Adobe/PDF/P100GBVW.pdf