Hydrocarbon oil-contaminated soil assessment using electrical resistivity topography

In Kuwait, oil wells exploded in 1991 have created numerous massive oil lakes, which have subsequently dried and contaminated the soil. A research project was initiated to delineate the type and extent of contaminated soil using an area survey method, namely Electrical Resistivity Topography (ERT), to examine dry oil lakes located in Bahra, Subiya. The specific objective was to assess the applicability of the environmentally friendly ERT to assist in the design of measures to remediate the contaminated land. ERT results were generated by testing a grid in both contaminated and non-contaminated areas. In addition, conventional soil boreholes were used to explore the sub-surface profile and depth of contamination in these areas for comparison with ERT results. In-situ and laboratory physical and chemical tests were performed on soil samples collected from the site to identify the contamination type and concentration as well as variation in the physical properties of the soil profile with depth. Results indicated the contamination depth to be 1.2 m from the ground surface. These results were also confirmed by borehole analyses (chemical and physical). Chemical tests indicated that the contamination consists of hydrocarbons. The findings demonstrate that ERT can be used to establish a baseline in the assessment of potential hydrocarbon-contaminated sites and is applicable for determining the type and depth of contamination without the need for expensive and tedious boreholes and in-situ and laboratory soil testing.