Geophysical and Physico-Chemical Analysis ofSoil and Water in the Vicinity of Waste Disposal Site, Kpakungu, Minna, Niger State, Nigeria.

Abstract

The environmental pollution of groundwater around Kpakungu, under bridge due to contaminant potential of leachate from the waste disposal site was investigated. This was done using Schlumberger array of Electrical resistivity method. The result was interpreted using a computer iteration called IP2Win. The interpretation of electrical resistivity models revealed regions of very low resistivity of an average depth of 4.7 m to beyond an average depth of 9.0 m for both transverses. These regions of very low resistivity could be contamination zones of the subsurface beneath the profiles resulting from leachate seeping into the soil and or ground water from the waste dump. The Vertical Electronic Sounding (VES) points taken in the refuse dump show a low resistivity zone of 20.0 to 27.3 Ωm down to a depth of 9 m. The four VES points outside the dumpsite also reveal that the groundwater is free from pollution. The values of resistivity from control site show a low resistivity zone of 89.6 to 180 Ωm for maximum depth of 2.89 m. The concentrations of the heavy metals like zinc, lead, manganese, iron, copper, chromium, nickel, cobalt and cadmium in the soil and groundwater samples were determined using a 210 VGP Buck Scientific Atomic Absorption Spectrophotometer. Water in this area is found to be contaminated by Lead,Chromium and Cadmium with level of contamination exceeding WHO (2004) regulated guidelines. Integrating the results of the electrical resistivity survey and the heavy metal determination of soil and groundwater revealed probable ground water contamination zones and the heavy metals that could result in the contamination.