Hydrocarbon oil-contaminated soil assessment using electrical resistivity topography

Abstract

In Kuwait, oil wells exploded in 1991 have created numerous massive oil lakes, which havesubsequently dried and contaminated the soil. A research project was initiated to delineatethe type and extent of contaminated soil using an area survey method, namely ElectricalResistivity Topography (ERT), to examine dry oil lakes located in Bahra, Subiya. The specificobjective was to assess the applicability of the environmentally friendly ERT to assist inthe design of measures to remediate the contaminated land. ERT results were generated bytesting a grid in both contaminated and non-contaminated areas. In addition, conventional soilboreholes were used to explore the sub-surface profile and depth of contamination in theseareas for comparison with ERT results. In-situ and laboratory physical and chemical testswere performed on soil samples collected from the site to identify the contamination typeand 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 resultswere also confirmed by borehole analyses (chemical and physical). Chemical tests indicatedthat the contamination consists of hydrocarbons. The findings demonstrate that ERT can beused to establish a baseline in the assessment of potential hydrocarbon-contaminated sitesand is applicable for determining the type and depth of contamination without the need forexpensive and tedious boreholes and in-situ and laboratory soil testing.