Lawal, T.O.Orosun, M.M.Ige, S.O.Sunday, J.A.Shehu, A.T.Bello, S.A.Nwankwo, L.I.2023-05-032023-05-032017-07-263. Lawal, T. O., Orosun, M. M., Ige, S. O., Sunday, J. A., Shehu, A. T., Bello, S. A. & Nwankwo, L. I. (2017): Geophysical Investigation of Groundwater Contamination in a Solid Waste Disposal Site. Al-Hikmah Journal of Pure & Applied Sciences. 5, 8-16https://uilspace.unilorin.edu.ng/handle/20.500.12484/9478A geophysical investigation of groundwater contamination within the solid waste disposal site was carried out at Tanke Tipper Garage, a typical non-controlled open dumpsite located in Ilorin, Nigeria. The aim of the investigation is to study the spatial distribution of contaminant plumes in the groundwater and ascertain if areas that can be free from contaminants are available in the study area. In view of this, four (4) vertical electrical soundings (VES) methods employing Half Schlumberger electrode array were conducted due to limited space in the area with maximum electrode spacing of 50 m. The field data were processed and Interpreted Resistivities Values were obtained by iterative computer modeling of the apparent resistivity data. The interpreted resistivity value showed that contaminant plumes at low zones with values ranging between 30.2 and 81.5 ohm-m extending from the surface down to the aquifer of shallow groundwater of less than 15 m. The hydraulic conductivity of the subsurface layers of interpreted VES points was also calculated and values ranging between 0.076 m/s and 0.418 m/s were obtained respectively. In order to complement the result of geophysical data, a physiochemical analysis of water samples from the existing hand dug well within the premises of the dumpsite was also conducted and high values of measured parameters were observed. This is an indication of groundwater contamination resulting from the solid waste leachate accretion found within the shallow aquifer zones.enDump site, Electrical resistivity, Half Schlumberger, Leachate plumeArticle