Abstract

Hazardous waste drums buried more than 20 years ago were successfully located by conducting a cost-effective, surface geophysical survey at a 1-acre property in a mixed-use residential and commercial area of a midwestern community. An electromagnetic induction tool that generates a pulsed primary magnetic field was used to locate four distinct areas of buried metallic objects.

The geophysical survey data were indispensable in the collection of representative soil and soil vapor samples adjacent to the identified target areas. Field and laboratory analytical results of soil and soil vapor samples confirmed the relationship of subsurface contamination with the target areas delineated by the geophysical survey. The distribution of contaminants was documented as occurring at two distinct depth levels in the subsurface.

The geophysical survey was invaluable in accurately identifying known and unknown buried drum locations, in planning and conducting soil and soil vapor sampling, and in minimizing volumes of excavated sediment during drum removal. Soil and soil vapor sampling provided important information for health and safety planning and for identifying cost-effective excavation and waste disposal options. Locations and depths of groundwater monitoring wells were determined on the basis of the geophysical and soil vapor surveys and the results of the excavation.