Investigating groundwater pollution at an open dumpsite using 2D geoelectrical resistivity imaging and vertical electrical sounding

Geoelectrical resistivity survey has been conducted within the Kurata dump site in Ota, south-western Nigeria. This present study focuses on the use of 2D resistivity imaging and Vertical Electrical Sounding to delineate conductive leachate point and degree of movement within the subsurface for conceivable groundwater pollution. The 2D resistivity survey was carried out using the ABEM Terrameter (SAS 1000/4000) System with multiple-gradient array electrode configuration. The Vertical Electrical Sounding was conducted using the schlumberger electrode configuration. One 2-D imaging profile of length 100m and one Vertical Electrical Sounding of length 200m were acquired on the established traverse. The resistivity data was inverted utilizing RES2DINV and WinResist to obtain the inverse model resistivity distribution. The 2D inverse resistivity models of the subsurface showed that the study site has a multi-layered aquifer system, four geoelectrical layers were inferred from the resistivity imaging and they are lateritic clay, clayey sand, sandy clay and coarse sand units. There is one aquifer system about 13 m which is highly polluted. The unpolluted aquifer system is localized around 19 m with inverted resistivity range 498 Omega m - 685 Omega m in the traverse. Also there might be conceivable sullying of deep groundwater system in the long term if appropriate moderation procedures are not thought about at the area.