Electrical Resistivity Investigation of Dumpsites in Gusau Metropolis, Zamfara State, Nigeria

Abstract

Electric resistivity survey was carried out in three selected dumpsites in Gusau metropolis for groundwater contamination. The dumpsites were investigated by conducting Vertical Electrical Soundings (VES) using Schlumberger array with maximum current electrode separations of 180 m. Five VES were conducted on each dumpsite making a total of fifteen VES along three profiles. The field data obtained from VES were analyzed using WinGlink softwar. The VES results revealed three subsurface layers. The topsoil had resistivity ranging from 1.45 Ωm to 48.2 Ωm while the thicknesses varied from 0.47 m to 3.37m across the profiles. The second layer's resistivities varied from 5.4 Ωm to 144.35 Ωm and their thicknesses' ranges from 1.36 m to 16.93 m. The third geoelectric layer had resistivity from 70.0 Ωm to 6003.0 Ωm. The results indicated that the top soils in all the dumpsites were characterized by very low resistivity depicting possible pollution and contamination. Findings from this study indicated that there may be possible contamination of shallow groundwater system in the nearest future if proper mitigation measures are not taken into consideration at the dumpsites.