Subsurface Beddings, Characterization of Hydrogeological Potential, and Identification of Potential Hazards in Parts of Rumuosi, Obio-Akpo Local Government Area, Rivers State, Nigeria

The objective of this paper was to delineate the subsurface lithology, characterize hydrogeological potential, and identify potential hazards in parts of Rumuosi, Obio-Akpo Local Government Area, Rivers State, Nigeria using a combination of vertical electrical sounding (VES) cross plots and 2-dimensional electrical resistivity Tomography (ERT). Data acquired on inverted resistivity tomograms revealed an alternating subsurface depths at shallow layers of high (≈500-824Ωm) and moderate (≈183-291Ωm) resistivity, indicating high lateral heterogeneity and moderate resistivity, suggesting a significant volume of saturated sand, while the second inverted resistivity tomogram shows an extreme low-resistivity anomaly (as low as 10.4Ωm) that dominates the subsurface. This anomaly is consistent both vertically and laterally, contrasting sharply with the resistive shallow layers. The moderate resistivity zone (≈291–500Ωm) identified delineated the major saturated sand aquifer of the Benin Formation. The tomogram near the dumpsite revealed an extreme low resistivity anomaly (≈10.4Ωm) extending deeply. This anomaly conclusively identifies a widespread and penetrating conductive leachate plume, which poses a serious environmental contamination threat to the underlying aquifer system. The findings underscore the critical role of integrated geophysical techniques in guiding sustainable infrastructure development and environmental remediation efforts in the Niger Delta.