Bulletin of the Geological Society of Malaysia, Volume 57, December 2011, pp. 19-25
1Pusat Pengajian Sains Sekitaran dan Sumber Alam, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor, Malaysia
2Agensi Nuklear Malaysia, MOSTI
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Abstract: Subsurface contamination by light non-aqueous phase liquids (LNAPLs) is one of the most pressing environmental issues in the industrialized and developing world. Non-invasive geophysical techniques have proven to be effective in identifying contaminated areas. In this study, a 2D electrical resistivity imaging and ground penetrating radar (GPR) survey has been carried out at a site to investigate the nature and extent of an oil spill into sandy soil and groundwater from old transformers at an abandoned power station. Hand-augered boreholes revealed that the water level was at 1.5 m and shallower towards the coastline, which is about 100 m from the site. The presence of several oil plumes were detected at the top of the water table in 2D resistivity sections as a zone of high resistivity with values ranging from 450 to 1000 Ωm. The low resistivity zones below the water table are interpreted as saline water. In the GPR section, the oil contaminated layer exhibits discontinuous, shadow and chaotic high amplitude patterns.
Keywords: electrical resistivity imaging, ground penetrating radar, oil spill