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Impact of CO2 Intrusion into USDWs, the Vadose Zone, and Indoor Air
Citation:
DIGIULIO, D. C. AND R. T. WILKIN. Impact of CO2 Intrusion into USDWs, the Vadose Zone, and Indoor Air. Presented at DOE/EPA Collaborative Review, Pittsburgh, PA, March 23 - 24, 2010.
Impact/Purpose:
This study will serve as a natural analogue to evaluate potential CO2 intrusion into buildings due to GS.
Description:
The U.S. Environmental Protection Agency’s (EPA) Water Research Program in the Office of Research and Development is conducting research to better detect and quantify leakage into USDWs, the vadose zone, the atmosphere, and buildings. Research in this initiative is focused in three topical areas: (1) Evaluation of Leakage through Well Penetrations, (2) Gas Intrusion, and (3) Soil-Gas Method Development. Soil-gas, gas flux, and ground-water monitoring will be conducted at an enhanced oil recovery site and/or a site where CO2 will be injected into a saline aquifer to assess the potential for leakage from well penetrations, especially abandoned wells. Measurements will be conducted near and away from well penetrations to detect “spot anomalies” prior to and during injection of CO2. This concept is similar to the use of soil-gas surveys to locate gas release from faults and fractures in volcanic or geothermal areas where magna degassing or thermo-metamorphic alteration of carbonates produces large volumes of CO2 and the use of soil-gas surveys for mineral or petroleum/natural gas exploration. Intrusion of sub-surface gases into buildings will be evaluated at a housing division near Wichita, Kansas where depletion of oxygen and buildup of CO2 has been documented in indoor air after a heavy infiltration event. This study will serve as a natural analogue to evaluate potential CO2 intrusion into buildings due to GS. During commercial application of GS, it will be necessary to have a protocol to discern the cause of elevated levels of CO2 to avoid an unnecessary shut down of a GS system and potential public overreaction. Despite the long-term use of soil-gas sampling to support resource exploration and hazardous waste investigations, quality assurance and control measures are poorly documented or lacking. Research on leak, purge, and gas permeability testing, will be conducted to support application of GS.