This research evaluates groundwater quality in Effurun, southern Nigeria, particularly focusing on contamination from solid waste sources such as dumpsites and abattoirs in Osubi, Ugbomro, and Agbarho. Employing a combination of fifteen Wenner-Werner arrays and vertical electrical sounding (VES) data, we conducted geophysical assessments to identify contamination levels. Using the WINRESIST and RES 2D inversion software, resistivity models revealed significant contamination at values below 50 Ohm-meters, with lateral extents ranging from 49 to 85 meters and depths up to 6.39 meters. Notably, the Osubi site (abattoir) exhibited the highest contamination, while some areas in Ugbomro and Agbarho remained less affected. The findings highlight the vulnerability of unconfined aquifers, characterized by weak protective layers, to pollutants, necessitating urgent improvements in waste management and groundwater protection strategies. Additionally, Dan Zarrouk parameters indicated low aquifer protective capacity in key areas, correlating with observed contamination. This study underscores the critical need for targeted interventions to safeguard groundwater resources amid rising industrialization and waste generation in the region.

Keywords: Electrical resistivity, Groundwater Contaminant, Aquifer, Danzarouk parameter,