Detection of Leachate Plumes Migration Using Vertical Electrical Sounding Method and Physicochemical Analysis at Kpagungun, Minna, Niger State, Nigeria.

Abstract

The aim of this study is to use electrical resistivity method and heavy metal determination as indicators for groundwater pollution at a waste dump site to map leachate plumes and determine the extent of groundwater contamination at Public Dump Site in Kpagungun, Minna. Twenty VES points with an electrode spacing’s of AB/2 80 m were occupied along three traverses. Surface data were acquired with an ABEM SAS 4000 terrameter set. Data were processed by conventional curve matching and computer iteration methods using Win Resist Software. VES data were plotted as pseudo sections to provide information on resistivity distribution and geo-electric sections were generated from VES interpretations which revealed second and third layers to be mainly clayey sand and lateritic soils of low resistivity values which varied with distance; an indication of leachate migration. The interpretation of electrical resistivity models revealed regions of very low resistivity (14.8 -25.3 Ωm) to be from an average depth of 4.5 m to an average depth of 17.8 m for profile A; and to a maximum depth of 11.3 m for profile B. 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 groundwater from the waste dump. The result of the heavy metal determination reveal that concentration of heavy metals (water sample collected from hand dug well and soil sample collected at the waste dump site) was more than that of profile C (water sample collected from hand dug well away from the waste dump site). In terms of WHO, 2011 guideline for drinking water quality, Lead, Chromium and Cadmium are above the guideline values in both water samples.