Electrical Imaging Characterization of a Dumpsite on an Abandoned Quarry Site in Abeokuta, South West, Nigeria
Akintayo O. Ojo, O. T. Olurin, S. A. Ganiyu, B. S. Badmus, O. A. Idowu
Abstract
A resistivity imaging technique was employed to delineate the degree of leachate plume accumulation and migration for possible groundwater pollution in the subsurface of Saje dumpsite on an abandoned quarry site within the Abeokuta metropolis, Ogun State, Nigeria. A total of twenty-five 2D profiles were mapped, adopting Wenner configuration using Ohmega resistivity meter with electrode spacing ranging from 5-25 m and profile lengths of 100 m. The 2D and 3D inversions of the data were carried out by RES2DINV and RES3DINV software, respectively. The inversions revealed both the lateral and vertical extents of conductive zones, mostly in fractured zones that served as the contaminant pathways. The 3D volumetric visualizations of the subsurface were generated by Voxler 4. The 2D and 3D models depicted regions with low resistivity anomalies ranging from 1.33-70.70 and 4.70-13.20 Ωm to maximum penetrated depths of 13.4 and 21.9 m, respectively. This study identified zones of concentrated pollution to depths that could have reached the water aquifer and indicated contaminants migration pathways that could endanger the groundwater as the dumpsite ages.