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Research Article Volume 8 Issue 1
Mapping leachate migration and groundwater risk in Port Harcourt: geoelectrical insights from ten open dumpsites
Tomquin Abiye, Augusta Ayotamuno, Ifeanyichukwu Clinton Ezekwe, Morufu Olalekan Raimi, Godspower Imiete
Received: July 16, 2025 | Published: September 5, 2025
Citation: Abiye T, Ayotamuno A, Ezekwe IC, et al. Mapping leachate migration and groundwater risk in Port Harcourt: geoelectrical insights from ten open dumpsites. Open Access J Sci. 2025;8(1):187-201. DOI: 10.15406/oajs.2025.08.00263
Abstract
Dumpsite-induced groundwater contamination remains a pressing environmental and public health issue in urban and peri-urban areas of Nigeria. Leachate infiltration from poorly managed waste disposal sites poses severe threats to aquifer integrity and potable water safety. Given the rapid urban expansion and lack of engineered landfill systems, there is an urgent need to evaluate subsurface pollution patterns using non-invasive geophysical techniques. This study aimed to delineate leachate migration patterns and assess the vulnerability of groundwater resources in the vicinity of selected dumpsites within the Port Harcourt metropolis using electrical resistivity methods. It further sought to compare the extent of subsurface contamination across multiple locations and provide scientific justification for sustainable waste and water resource management. A total of ten dumpsites (Eliozu, Rumuolumeni, Choba, Eneka, Rumepirikom, Rumuagholu, Sasun, Oyigbo, Rumuola, and Eleme) were investigated using Vertical Electrical Sounding (VES) and 2D Electrical Resistivity Tomography (ERT). Schlumberger electrode configurations were employed to generate pseudo-sections and resistivity inversion models. Data interpretation focused on identifying zones of low resistivity associated with leachate-impacted layers. These geophysical outputs were correlated with established hydrological models and previous studies on dumpsite-induced contamination. The geoelectric models revealed varying degrees of subsurface contamination across all sites. Low resistivity zones (as low as 0.3–6.84 Ωm) were identified at shallow to intermediate depths (1–20 m), confirming leachate infiltration into sandy and clayey formations. Sites like Rumuola and Eliozu exhibited deep contamination profiles, reaching 24 m and 20 m, respectively. In contrast, Oyigbo and Rumuolumeni showed shallower contamination (2–6 m), indicating either newer waste deposits or more resistive soil matrices. High resistivity layers (>1000 Ωm), interpreted as potential aquifers, were generally found at depths exceeding 14 m, often beneath the contaminated zones. The findings confirm the widespread vertical and lateral migration of leachate plumes from open dumpsites into the subsurface, threatening the integrity of underlying aquifers. Electrical resistivity profiling proved effective in identifying contamination hotspots and mapping pollution pathways. The spatial heterogeneity in leachate penetration highlights the role of local geology and hydrology in influencing contaminant behavior. Based on the findings, it is recommended that immediate remediation efforts be prioritized at dumpsites with deeper leachate infiltration, such as Rumuola and Eliozu, through the installation of engineered liners and leachate recovery systems to curb further contamination. Borehole drilling for potable water should be strategically planned to avoid vulnerable zones, targeting deeper, uncontaminated aquifer layers. Government and environmental agencies should institutionalize routine groundwater monitoring in communities surrounding dumpsites to detect early signs of pollution. Additionally, transitioning from open dumping to sanitary landfilling with appropriate environmental safeguards must be enforced through updated waste management policies, supported by public awareness campaigns and infrastructure investments aimed at sustainable waste disposal practices. The presence of leachate-impacted zones within shallow aquifers poses serious risks for public health, including exposure to toxic metals, pathogens, and organic pollutants. Consumption of groundwater from these zones can lead to chronic illnesses, reproductive disorders, and developmental toxicity. Protecting groundwater in wasteimpacted areas is therefore a critical component of environmental health policy.
Keywords: Geoelectrical Profiling; Groundwater Contamination; Resistivity Tomography; Leachate; Schlumberger Array; Aquifer Protection; Sanitary Landfills; Waste Management; Environmental Health; Port Harcourt; Nigeria
©2025 Abiye, et al. This is an open access article distributed under the terms of the, which permits unrestricted use, distribution, and build upon your work non-commercially.