Journal of Emerging Trends in Engineering and Applied Sciences: Research Areas

Article Title: Geoelectric Delineation of Structurally-Controlled Leachate Plume Around Otutubiosun Dumpsite, Akure, Southwestern Nigeria
by S. Bayode; G. O. Omosuyi; K. A. Mogaji and S. T. Adebayo

Abstract:
A direct current electrical resistivity survey using the Schlumberger Vertical Electrical Sounding (VES) and dipole - dipole profiling techniques have been used to map structurally controlled pollution plume around the Otutubiosun dumpsite, Akure, southwestern Nigeria. The geoelectric interpretation and the inverted 2-D resistivity structures revealed three subsurface layers: the topsoil, weathered layer and the fractured/fresh basement rock. The fractured/fresh basement constitutes the basement bedrock. The weathered layer and the fractured/faulted zones constitutes the major aquifer units in the study area. Topsoil resistivity and thickness value ranges from 5 - 107 ohm-m and 0.2 - 2.7 m respectively. The weathered layer resistivity values vary from 4 - 35 ohm-m while its thickness ranges from 1.1 - 12.9 m beneath the dumpsite. The depth to the bedrock varies from 2.2 - 13.1 m. The resistivity values of the fractured/fault zones rages from 2 - 55 ohm-m and the thickness varies from 10 - 30 m. The 2-D resistivity structures show that zones with relatively low resistivity values of (< 35 ohm-m) with a depth range of 1.1 - > 15 m for topsoil, weathered layer and fractured/faulted basement zones are suspected to be due to leachate saturation. Due to the observed relatively shallow water table of 0.5 - 2.0 m around the dumpsites the groundwater around the dumpsites is suspected to have been polluted. This study reveals that subsurface geologic structures within the bedrock (fractures/faults) control the migration of leachate plume around the investigated dumpsite

Keywords: geoelectric, delineation, geologic structure, dumpsite, leachate plume, migration

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