Abstract

*Omamode Samuel Marere, Essono Emmanuel Allen

ABSTRACT

This study utilizes an integrated geophysical and geochemical approach to evaluate groundwater contamination in aquifers located beneath an abandoned dumpsite in Ogbovwan Town, Delta State, Nigeria. The main goal is to assess the degree of leachate penetration into the aquifer system and its impact on water quality. Geophysical methods, such as Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES), are combined with geochemical analysis of groundwater samples to comprehensively understand the subsurface conditions and contamination levels. The analysis shows that the mean pH concentration of the groundwater is 4.625, which is below the recommended WHO (2011) and NSDWQ (2007) standards of 6.5-8.5, indicating that the groundwater is acidic. This acidity can significantly impact water quality by increasing the solubility and mobility of metals. Additionally, the mean levels of lead (Pb) and cadmium (Cd) are found to be 0.013 mg/L, exceeding the permissible limits set by WHO and NSDWQ, highlighting the presence of contaminants in the groundwater, making it unsafe for drinking. Geophysical survey results further identify low-resistivity zones beneath the dumpsite, suggesting leachate infiltration into the subsurface layers. This finding confirms that contaminants from the dumpsite are migrating into the aquifer, impacting the groundwater quality within the research location.