Experiments and Modeling of the Soil-Gas Transport of Volatile Organic Compounds into a Residential Basement: Revision

摘要

It is assumed that the major pathway for migration of contaminants from landfills was through contamination and movement of groundwater. The migration of methane gas from landfills into nearby residences has indicated the importance of gas-phase transport. Research on the entry of radon gas into houses indicates that the pressure-driven entry of soil gas can result in high indoor concentrations of soil-gas contaminants. This paper presents theoretical and laboratory studies of the advective flow of volatile organics compounds (VOC) through soil, and a field investigation of the pressure-driven entry of VOC into a house adjacent to a municipal landfill. The principals of fluid mechanics are used to derive an analytical model of the pressure-driven flow of VOC in soil. The calculation results in the definition of a retardation factor of VOC with respect to the velocity of the bulk soil gas. The retardation equation is then tested in soil-column experiments using sulfur hexafluoride (SF6) and hexafluorobenzene (HFB). These experiments are used to evaluate the potential of SF6 and HFB as tracer gases for use in a field investigation of the advective flow of soil gas into and near the basement of a house near a landfill and to evaluate the potential of the soil-column apparatus for use in screening the advective mobility of VOC important as landfill gas contaminants. The field study consisted of experiments investigating the influence of basement depressurization on the surrounding soil gas, and quantifying VOC contamination at the site. Soil-gas entry into the house during artificial basement depressurization was measured using SF6 as a tracer, and pressure coupling was measured between the basement and the surrounding soil. Measurements of VOC in ambient air, indoor air, and soil gas indicate that a number of halogenated and oxygenated contaminants present in indoor air had a soil-gas source. 39 refs., 24 figs., 9 tabs. (ERA citation 14:014976)