COMBINED GEOPHYSICAL INVESTIGATION TECHNIQUES TO IDENTIFY BURIED WASTE IN AN UNCONTROLLED LANDFILL AT THE PADUCAH GASEOUS DIFFUSION PLANT, KENTUCKY
The primary objective of the investigation was to confirm the presence and determine the location of a cache of 30 to 60 buried 55-gallon drums that were allegedly dumped along the course of the pre-existing, northsouth diversion ditch (NSDD) adjacent to permitted landfills at the Paducah Gaseous Diffusion Plant, Kentucky. The ditch had been rerouted and was being filled and re-graded at the time of the alleged dumping. Historic information and interviews with individuals associated with alleged dumping activities indicated that the drums were dumped prior to the addition of other fill materials. In addition, materials alleged to have been dumped in the ditch, such as buried roofing materials, roof flashing, metal pins, tar substances, fly ash, and concrete rubble complicated data interpretation. Some clean fill materials have been placed over the site and graded. This is an environment that is extremely complicated in terms of past waste dumping activities, construction practices and miscellaneous landfill operations. The combination of site knowledge gained from interviews and research of existing site maps, variable frequency EM data, classical total magnetic field data and optimized GPR lead to success where a simpler less focused approach by other investigators using EM-31 and EM-61 electromagnetic methods and unfocused ground penetrating radar (GPR)did not produce results and defined no real anomalies. A variable frequency electromagnetic conductivity unit was used to collect the EM data at 3,030 Hz, 5,070 Hz, 8,430 Hz, and 14,010 Hz. Both in-phase and quadrature components were recorded at each station point. These results provided depth estimates for targets and some information on the subsurface conditions. A standard magnetometer was used to conduct the magnetic survey that showed the locations and extent of buried metal, the approximate volume of ferrous metal present within a particular area, and allowed estimation of approximate target depths. The GPR survey used a 200 megahertz (MHz) antenna to provide the maximum depth penetration and subsurface detail yielding usable signals to a depth of about 6 to 10 feet in this environment and allowed discrimination of objects that were deeper, particularly useful in the southern area of the site where shallow depth metallic debris (primarily roof flashing) complicated interpretation of the EM and magnetic data. Several geophysical anomalies were defined on the contour plots that indicated the presence of buried metal. During the first phase of the project, nine anomalies or anomalous areas were detected. The sizes, shapes, and magnitudes of the anomalies varied considerably, but given the anticipated size of the primary target of the investigation, only the most prominent anomalies were considered as potential caches of 30 to 60 buried drums. After completion of a second phase investigation, only two of the anomalies were of sufficient magnitude, not identifiable with existing known metallic objects such as monitoring wells, and in positions that corresponded to the location of alleged dumping activities and were recommended for further, intrusive investigation. Other important findings, based on the variable frequency EM method and its combination with total field magnetic and GPR data, included the confirmation of the position of the old NSDD, the ability to differentiate between ferrous and non-ferrous anomalies, and the detection of what may be plumes emanating from the landfill cell.
- Research Organization:
- Advanced Geological Services, Inc., 3 Mystic Lane, Malvern, PA 19355 (US); PMC Environmental, 1700 Rockville Pike, Suite 400, Rockville, MD 20852 (US)
- Sponsoring Organization:
- US Department of Energy (US)
- OSTI ID:
- 825946
- Resource Relation:
- Conference: Waste Management 2003 Symposium, Tucson, AZ (US), 02/23/2003--02/27/2003; Other Information: PBD: 27 Feb 2003
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
12 MANAGEMENT OF RADIOACTIVE WASTES, AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
54 ENVIRONMENTAL SCIENCES
FLY ASH
GASEOUS DIFFUSION PLANTS
MAGNETIC FIELDS
MAGNETIC SURVEYS
MAGNETOMETERS
MONITORING
PLUMES
QUADRATURES
RADAR
ROOFS
SANITARY LANDFILLS
TAR
TARGETS
WASTE MANAGEMENT
WASTES