Soil-Gas Surveying for Subsurface Gasoline Contamination Using Total Organic Vapor Detection Instruments Part I. Theory and Laboratory Experimentation

Authors

  • Gary A. Robbins,

    1. Dr. Gary A. Rabbins is an associate professor of Hydrogeology at the University of Connecticut (Department of Geology and Geophysics, Mail Stop U-45, Storrs, CT 06269). He has been previously employed as a senior project hydrogeologist with Woodward- Clyde Consultants, as a lecturer and assistant professor at Texas A&M University, and as a project geologist with the U.S. Nuclear Regulatory Commission.
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  • Brendan G. Deyo,

    1. Brendan G. Deyo is a graduate student in hydro- geology at the University of Connecticut (Department of Geology and Geophysics, Mail Stop U-45, University of Connecticut, Storrs, CT 06269) and is working toward an M.S. degree. He graduated from Wesley an University in environmental science in 1987, and has worked for Clean Harbors Inc., Natick, Massachusetts, as a field chemist in hazardous waste disposal.
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  • Mark R. Temple,

    1. Mark R. Temple is a senior hydrogeologist with Leonard Engineering Inc., Storrs, Connecticut. He is completing his M.S. degree in hydrogeology at the University of Connecticut (Department of Geology and Geophysics, Mail Stop U-45, University of Connecticut, Storrs, CT 06269). He received his B.S. degree in geology in 1979 from Southern Connecticut State University, and was previously employed for seven years by Western Geophysical Co. of America as a party chief.
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  • James D. Stuart,

    1. Dr. James D. Stuart is an associate professor of Chemistry at the University of Connecticut (Department of Chemistry, Mail Stop U-60, University of Connecticut, Storrs, CT 06269). He has taught as an instructor at Lafayette College and has conducted research at Yale University and the University of Georgia. His research involves developing new separation methods for environmental and medical applications.
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  • Michael J. Lacy

    1. Michael J. Lacy is a Ph.D. student in analytical chemistry at the University of Connecticut (Department of Chemistry, Mail Stop U-60, University of Connecticut, Storrs, CT 06269). He received his B.S. in chemistry from Monmouth College in 1987, and formerly was employed with PACO Packaging of Lakewood, New Jersey, in its analytical chemistry laboratory.
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Abstract

Factors influencing the response of total organic vapor detection instruments used in soil-gas surveying for subsurface gasoline leakage were investigated through performing theoretical assessments and laboratory experiments. Theoretical assessments indicate that total organic vapor measurements will depend on response conditions and the relative concentration of constituents in soil gas, in addition to absolute constituent levels. Laboratory tests conducted using flame ionization, photoionization and explosimeter devices indicated that conditions influencing their responses included instrument flow rate and soil-air permeability when performing direct-probe sampling; the linear range of the instrument; the multicomponent nature of gasoline vapors; and levels of oxygen, nitrogen, carbon dioxide and relative humidity in soil air. If an instrument's response to these conditions is not taken into account, survey results may be misleading. To circumvent adverse instrument responses, a serial dilution technique is presented.

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