Application of Surface Geophysics for Location of Buried Hazardous Wastes

Abstract Surface geophysical techniques represent powerful tools for investigations involving the delineation of buried hazardous wastes. When properly conceived and implemented, substantial benefits can be realized. This was clearly the case during an investigation to assess an 8 hectare (20 acres) manufacturing plant site for the presence of buried waste materials. Electromagnetic (EM) conductivity and magnetometry data were collected along continuous profiles and within rectangular systematic grids. The results of this work dispelled concern over several areas rumored to contained buried wastes, but indicated the potential presence of buried materials at three areas. The EM quadrature-phase conductivity data proved to be most definitive as conductivity anomalies were distinct and readily apparent. In an area suspected to contain an abandoned seepage pit, the measured EM conductivities exceeded 25 milli mhos/meter (mmho m −1 ), more than twice as high as background levels (sandy loam soil/till profile). In two areas suspected of containing buried metal drums, EM conductivity values approached 70 mmho m −1 . In all three areas, the buried waste boundaries as predicted by the geophysical anomalies matched very well with the boundaries actually encountered during waste exhumation and clean up.