145-7 Groundwater Contamination Risk and Geophysical Assessment of the Extent of Groundwater Contamination in Solous Landfill Sites

Session: Dynamics of Natural and Built Environments (Posters)

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Improper selection of landfill sites can expose the groundwater to leachate plumes, which often results in different health challenges for people drinking from polluted aquifers. In this study, integrated groundwater risk and geophysical assessment were performed to assess the extent of contaminants in the groundwater of a landfill environment in Igando, Lagos State, Nigeria. 2D Electrical Resistivity Tomography survey was conducted using a Wenner array and the data obtained were processed to generate resistivity structures. Groundwater physical parameters were measured, correlated and compared with established standards. The resistivity inversion data was used to determine the lithology as topsoil, clay, clayey sand, and sand. The inversion results showed that the subsurface has been affected by leachate plumes up to a depth of about 16m. The contamination index of wells closer to the landfill ranges from 0.57 – 0.93. Distance decay curve reveals that groundwater contamination reduces to 50% every 60 m from the source. Threshold exceedance and principal component analyses indicate wells closer to the landfill are severely contaminated. The strong indirect correlation between temperature and distance to the landfill shows an active decomposition of solid waste in the landfills. This decomposition will bring about the formation of more leachate which might increase the extent of groundwater contamination above 16m in the study area.

Geological Society of America Abstracts with Program. Vol. 57, No. 6, 2025

doi: 10.1130/abs/2025AM-9544

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