Subsurface mapping of groundwater contamination pathway using geoelectric method at waste site of Kubanni Basin, Zaria, Kaduna State, Nigeria

Abstract

Electrical resistivity Survey was carried out at Kubanni waste dumpsite of Ahmadu Bello University, Zaria, Kaduna state, Nigeria in order to study the groundwater contamination pathway. Vertical Electrical Sounding (VES) using Schlumberger array was carried out at fourteen (14) stations. Ohmega terrameter was used for data acquisition. The field data obtained has been analyzed using Computer Software (ipi2win)which gives an automatic interpretation of apparent resistivity. The VES result revealed the heterogeneous nature of the subsurface geologic sequence. The geologic sequence beneath the study area is composed of topsoil (sandy-clay and sandy-lateritic), weathered basement, fracture basement layer and fresh basement. The resistivity values of the layers ranges from 8.2Ωm to 2884Ωm. The extremely low resistivity variation in the weathered basement identify the present of contamination plume zones in the layer. However, fracture basement and fresh basement underlying the weathered basement show lateral variation in the basement resistivity. The result shows that the contamination plume zone has tendency to contaminate the ground water.

Keywords: Contamination, Fracture basement, Fresh basement, Geoelectric, Groundwater, Leachate, Weathered and Vertical Electric Sounding (VES)