f Numerical modeling comparison of the time domain EM, frequency domain EM and borehole-to-surface D.C. resistivity methods for delineation of shallow contaminant plumes

The mandates of Environmental protection organizations to identify the source and the extent of groundwater contamination and to assure the containment of wastes injected in deep disposal wells, have led to the assessment of geophysical methods for mapping contaminant plumes. Several studies have shown that many sites have distinct geophysical anomalies and a variety of geophysical technicques including seismic, potential fields, ground penetrating radar, electrical and electromagnetic (EM) methods have been successfully employed. Of all the geophysical techniques, the electrical and electromagnetic methods have had the most widespread use in the detection of plumes of inorganic chemicals .