Detecting and Monitoring Oil Contamination Using Electrical Resistivity

This study uses electrical resistivity tomography (ERT), recently introduced as a means of detecting contaminants in the subsurface, to detect oil pollution of sand. A total of 28 stainless steel stakes were placed in a tank filled with Ottawa sand having a moisture content of 2.5%. The stakes were connected to the electrodes of the Advanced Geosciences Inc. (AGI) Supersting R1. Several control surveys were run to obtain the electrical resistivity of the sand before and after application of the contaminant. Engine oil was poured at the surface point to observe changes in the electrical characteristics at the entry spot. Several tests were performed on different days to investigate how the contamination affected resistivity. Locations with oil concentration showed no major changes in electrical resistivity over a period of 7 days. ERT surveys were found useful in detecting oil plumes and their flow in sand.