HR: 0801h
AN: NS11B-0494    [Abstracts]
TI: Attenuated geophysical signatures associated with ongoing remediation efforts at Wurtsmith Air Force Base, Oscoda, Michigan
AU: * Che-Alota, V
EM: vukenkeng.che_alota@okstate.edu
AF: Boone Pickens School of Geoology, Oklahoma State University 105 Noble Research Center, Stillwater, OK 74078, United States
AU: Atekwana, E A
EM: estella.atekwana@okstate.edu
AF: Boone Pickens School of Geoology, Oklahoma State University 105 Noble Research Center, Stillwater, OK 74078, United States
AU: Atekwana, E A
EM: eliot.atekwana@okstate.edu
AF: Boone Pickens School of Geoology, Oklahoma State University 105 Noble Research Center, Stillwater, OK 74078, United States
AU: Sauck, W A
EM: bill.sauck@wmich.edu
AF: Department of Geosciences, Western Michigan University, Kalamazoo, MI 49007, United States
AU: Nolan, J T
EM: jtnolan@pegasus.rutgers.edu
AF: Earth & Environmental Sciences, Rutgers-Newark 101 Warren St., Newark, NJ 07102, United States
AU: Slater, L D
EM: lslater@andromeda.rutgers.edu
AF: Earth & Environmental Sciences, Rutgers-Newark 101 Warren St., Newark, NJ 07102, United States
AB: Previous geophysical investigations (1996, 1997, 2003, and 2004) conducted at the decommissioned Wurtsmith Air Force Base former Fire Training Cell (FT-02) showed a clearly defined high conductivity anomaly associated with hydrocarbon contaminants in the vadose zone and ground water near the source area. The source of the geophysical anomalies was attributed to biogeochemical modifications of the contaminated zone resulting from intrinsic bioremediation. During these previous surveys, ground penetrating radar (GPR) data showed a zone of attenuated GPR reflections extending from the vadose zone to below the water table. Self potential data (SP) data defined a positive anomaly coincident with the hydrochemically defined plume, while electrical resistivity data showed anomalously high conductivity within the zone of impact. In 2007, another integrated geophysical study of the site was conducted. GPR, SP, electrical resistivity, and induced polarization surveys were conducted with expectations of achieving similar results as the past surveys. However, preliminary assessment of the data shows a marked decrease in electrical conductivity and SP response over the plume. GPR data still showed the attenuated signals, but the zone of attenuation was only observed below the water table. We attribute the attenuation of the observed geophysical anomalies to ongoing soil vapor extraction initiated in 2003. Significant removal of the contaminant mass by the vapor extraction system has altered the subsurface biogeochemical conditions and these changes were documented by the 2007 geophysical and geochemical data. The results of this study show that the attenuation of the contaminant plume is detectable with geophysical methods.
DE: 0416 Biogeophysics
DE: 0418 Bioremediation
DE: 0424 Biosignatures and proxies
DE: 0432 Contaminant and organic biogeochemistry (0792)
DE: 0478 Pollution: urban, regional and global (0345, 4251)
SC: Near-Surface Geophysics [NS]
MN: 2007 Fall Meeting