USGS Groundwater Information: Branch of Geophysics
John W. Lane, Jr. (U.S. Geological Survey, Office of Ground Water, Branch of Geophysics, Storrs, CT)
Clifton C. Casey (U.S. Navy, Naval Facilities Engineering Command, Southern Division, Charleston, SC)
Frederick D. Day-Lewis (U.S. Geological Survey, Office of Ground Water, Branch of Geophysics, Storrs, CT; and Bucknell University, Lewisburg, PA)
Alan Witten (University of Oklahoma, Norman, OK)
Roelof J. Versteeg (Idaho National Environmental and Engineering Laboratory, Idaho Falls, ID)
Cross-hole and surface-to-borehole radar and conventional borehole geophysical logs were used to monitor subsurface injections of vegetable oil emulsion conducted as part of a field-scale biostimulation pilot project at the Anoka County Riverfront Park (ACP), located downgradient of the Naval Industrial Reserve Ordnance Plant (NIROP), in Fridley, Minnesota. The pilot project was undertaken to evaluate biostimulation using emulsified vegetable oil for treatment of ground water contaminated with chlorinated hydrocarbons. The objectives of the geophysical investigations were to delineate the distribution of vegetable oil injected at NIROP, and evaluate the utility of adding geophysical tracers to the vegetable oil emulsions.
Geophysical data were acquired by the U.S Geological Survey in five site visits over 1.5 years. This paper presents (1) level-run radar traveltime and amplitude data; (2) radar cross-hole traveltime tomograms; (3) vertical-radar profile diffraction tomograms; and (4) borehole electromagnetic induction logs. Based on comparison of pre- and post-injection data sets, a conceptual model was developed to define the distribution of emulsified vegetable oil and the extent of ground water having altered chemistry resulting from injections and, possibly, enhanced microbial degradation of chlorinated hydrocarbons. Radar slowness (reciprocal velocity) anomalies indicate that the emplaced oil emulsion remained close to the injection wells, whereas attenuation anomalies indicate changes in ground-water chemistry downgradient of all three injections.
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Final copy as submitted to Fourth International Conference on Remediation of Chlorinated and Recalcitrant Compounds for publication as: Lane, J.W., Jr., Casey, C.C., Day-Lewis, F.D., Witten, A., and Versteeg, R.J., 2004, Use of borehole radar methods and borehole geophysical logs to monitor a field-scale vegetable oil biostimulation pilot project at Fridley, Minnesota, in Proceedings of the Fourth International Conference on Remediation of Chlorinated and Recalcitrant Compounds, May 24-27, 2004, Monterrey California. Proceedings: Battelle Memorial Institute, CD-ROM, 9 pages.