2025/03/03 by Akintude, O. A.
#Electrical resistivity Tomography (ERT) #Groundwater #Hydrochemical analysis #Leachate Contamination #Vertical Electrical Sounding (VES)
paper · doi:10.60787/tnamp.v21.481
This study aims to evaluate the subsurface geoelectric properties and groundwater contamination near an old waste dumpsite in Temu, Epe-Orisha Local Government Area of Lagos State, using Electrical Resistivity Tomography (ERT) and Vertical Electrical Sounding (VES). The research specifically investigates the extent of leachate contamination and its impact on groundwater quality. A total of twenty-four VES and six ERT surveys were conducted using the PASI 16-GL Terrameter, employing Schlumberger and Wenner configurations. ERT profiles revealed distinct geoelectric layers, with low-resistivity zones (13–46 Ωm) indicating leachate contamination and high-resistivity areas (127–746 Ωm) suggesting minimal contamination. The VES data corroborated these findings, identifying contamination plumes at depths of up to 12 meters. Hydrochemical analysis of groundwater samples from nearby wells further confirmed contamination, with low pH levels and elevated concentrations of potassium, chloride, nitrate, iron, nickel, lead, and cadmium exceeding international drinking water standards (WHO, SON) which indicate the evidence of contamination. However, manganese and zinc levels remained within safe limits. These results align with borehole log data, enhancing the reliability of the interpretations. Given these findings, targeted remediation efforts should focus on low-resistivity zones, where contamination is most pronounced. Regular monitoring of subsurface conditions and groundwater quality is essential to mitigate environmental risks. Additionally, improved waste management practices and community education initiatives are recommended to prevent further leachate migration and ensure long-term environmental sustainability