2D Electrical Resistivity Imaging Investigation of Open Dump Site in Basement Complex Formation

A geophysical investigation involving 2D resistivit y survey was carried out on Aba Eku dump site in So uthwestern Nigeria with a view to map the conductive leachate plume and extent of migration of leachate plumes in the subsurface for possible groundwater contamination. The 2D resistivity survey was carried out using Wenner array confi guration of electrode spacing distance ranging from 5 ‐ 25 m. A total of thirteen (13) resistivity traverses were acquired within and outside the dump site. The 2D resistivity data wer e processed and inverted using RES2DINV code. The inverse resistivity models of the subsurface from 2D imaging revealed low resistivity value less than 10 Ωm suspected to be leachate infiltration. The extent of leachate migration was up to a depth of about 4 m, an indication that the underlying layer has a greater risk of contamination by leachate and decom posed solid waste materials. The 2D inverse resist ivity models of the subsurface revealed the extent of leachate plumes a nd allowed the location of leachate, clay soil, bed rock and seepage path from the dumpsite to be clearly delineated. There m ay be possible contamination of shallow groundwater system in the nearest future if proper mitigation measures are no t taken into consideration at the dumpsite.