Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings

This study employs geo-electric surveys and Vertical Electrical Sounding (VES) data, as well as a spatiotemporal assessment, to evaluate aquifer characteristics in the study area, with the main thrust of revealing significant subsurface variability, vulnerability, and the consequent contamination of...

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Main Authors: N.J. George, O.E. Agbasi, A.J. Umoh, A.M. Ekanem, N.I. Udosen, J.E. Thomas, M.U. Aka, J.S. Ejepu
Format: Article
Language:English
Published: Elsevier 2025-06-01
Series:Cleaner Water
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Online Access:http://www.sciencedirect.com/science/article/pii/S2950263224000589
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author N.J. George
O.E. Agbasi
A.J. Umoh
A.M. Ekanem
N.I. Udosen
J.E. Thomas
M.U. Aka
J.S. Ejepu
author_facet N.J. George
O.E. Agbasi
A.J. Umoh
A.M. Ekanem
N.I. Udosen
J.E. Thomas
M.U. Aka
J.S. Ejepu
author_sort N.J. George
collection DOAJ
description This study employs geo-electric surveys and Vertical Electrical Sounding (VES) data, as well as a spatiotemporal assessment, to evaluate aquifer characteristics in the study area, with the main thrust of revealing significant subsurface variability, vulnerability, and the consequent contamination of an aquifer system already established to be prolific. The study employed the DRASTIC model, integrated with geophysical resistivity methods, to assess groundwater vulnerability. Using Schlumberger electrode configurations, resistivity surveys at 19 VES locations provided insights into key aquifer parameters, including depth to groundwater, aquifer media, and vadose zone impact. This approach enhanced parameter accuracy for robust vulnerability assessments.The aquifers, primarily composed of fine to gravelly sands from the Benin Formation, exhibit high porosity and permeability. However, discrepancies in transmissivity, hydraulic conductivity, and permeability point to inconsistent groundwater behavior. Groundwater vulnerability, evaluated using the DRASTIC Index (DI), is classified as moderate to high, with influencing factors such as shallow water table depth (28 %), vadose zone properties (25 %), and net recharge (20 %). Predominantly H and K curve types suggest moderate to high contamination risks, while the region's topography and arenitic lithology exacerbate vulnerability due to slower filtration rates. The study emphasizes the need for careful groundwater management, given the aquifer's susceptibility to contamination. Regular monitoring is recommended, particularly in densely populated or agriculturally active areas, to mitigate contamination risks associated with the area's high permeability, porosity, and recharge variability. The DRASTIC model improves contamination risk assessment in sedimentary environments by analyzing several factors: depth to water (DTW), net recharge (NR), aquifer media (AM), soil media (SM), topography (T), the vadose zone (IPVZ), and hydraulic conductivity (C). Among these, DTW, IPVZ, and NR were the most sensitive contributors to the DRASTIC index (DI) for assessing vulnerability. AM and SM were moderately sensitive, while T and C had minimal impact. To effectively mitigate contamination, priority should be given to DTW, AM, and SM, with less focus on T and C. These insights help in better resource allocation and sustainable aquifer management.
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spelling doaj-art-4480c562490640b69bdd91ce8bebc83e2025-08-20T02:05:51ZengElsevierCleaner Water2950-26322025-06-01310006010.1016/j.clwat.2024.100060Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settingsN.J. George0O.E. Agbasi1A.J. Umoh2A.M. Ekanem3N.I. Udosen4J.E. Thomas5M.U. Aka6J.S. Ejepu7Department of Physics (Geophysics Research Group), Akwa Ibom State University, Mkpat Enin, Uyo, PMB 1162, Nigeria; Corresponding author.Okna Geoservices, Nigeria Limited, Eket, NigeriaDepartment of Science Laboratoty Technology, Faculty of Science and Technology, Heritage polytechnic, Eket, Ikot Udota, NigeriaDepartment of Physics (Geophysics Research Group), Akwa Ibom State University, Mkpat Enin, Uyo, PMB 1162, NigeriaDepartment of Physics (Geophysics Research Group), Akwa Ibom State University, Mkpat Enin, Uyo, PMB 1162, NigeriaDepartment of Physics (Geophysics Research Group), Akwa Ibom State University, Mkpat Enin, Uyo, PMB 1162, NigeriaDeartment of Physics, Faculty of science, Federal University of Technology, Ikot Abasi, NigeriaDepartment of Geology, Federal University of Technology, Mina, NigeriaThis study employs geo-electric surveys and Vertical Electrical Sounding (VES) data, as well as a spatiotemporal assessment, to evaluate aquifer characteristics in the study area, with the main thrust of revealing significant subsurface variability, vulnerability, and the consequent contamination of an aquifer system already established to be prolific. The study employed the DRASTIC model, integrated with geophysical resistivity methods, to assess groundwater vulnerability. Using Schlumberger electrode configurations, resistivity surveys at 19 VES locations provided insights into key aquifer parameters, including depth to groundwater, aquifer media, and vadose zone impact. This approach enhanced parameter accuracy for robust vulnerability assessments.The aquifers, primarily composed of fine to gravelly sands from the Benin Formation, exhibit high porosity and permeability. However, discrepancies in transmissivity, hydraulic conductivity, and permeability point to inconsistent groundwater behavior. Groundwater vulnerability, evaluated using the DRASTIC Index (DI), is classified as moderate to high, with influencing factors such as shallow water table depth (28 %), vadose zone properties (25 %), and net recharge (20 %). Predominantly H and K curve types suggest moderate to high contamination risks, while the region's topography and arenitic lithology exacerbate vulnerability due to slower filtration rates. The study emphasizes the need for careful groundwater management, given the aquifer's susceptibility to contamination. Regular monitoring is recommended, particularly in densely populated or agriculturally active areas, to mitigate contamination risks associated with the area's high permeability, porosity, and recharge variability. The DRASTIC model improves contamination risk assessment in sedimentary environments by analyzing several factors: depth to water (DTW), net recharge (NR), aquifer media (AM), soil media (SM), topography (T), the vadose zone (IPVZ), and hydraulic conductivity (C). Among these, DTW, IPVZ, and NR were the most sensitive contributors to the DRASTIC index (DI) for assessing vulnerability. AM and SM were moderately sensitive, while T and C had minimal impact. To effectively mitigate contamination, priority should be given to DTW, AM, and SM, with less focus on T and C. These insights help in better resource allocation and sustainable aquifer management.http://www.sciencedirect.com/science/article/pii/S2950263224000589Geo-resistivityContamination risk assessmentDRASTIC modelGroundwater contaminationVES curve amplitudeResistivity ratio
spellingShingle N.J. George
O.E. Agbasi
A.J. Umoh
A.M. Ekanem
N.I. Udosen
J.E. Thomas
M.U. Aka
J.S. Ejepu
Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings
Cleaner Water
Geo-resistivity
Contamination risk assessment
DRASTIC model
Groundwater contamination
VES curve amplitude
Resistivity ratio
title Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings
title_full Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings
title_fullStr Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings
title_full_unstemmed Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings
title_short Enhanced contamination risk assessment for aquifer management using the geo-resistivity and DRASTIC model in alluvial settings
title_sort enhanced contamination risk assessment for aquifer management using the geo resistivity and drastic model in alluvial settings
topic Geo-resistivity
Contamination risk assessment
DRASTIC model
Groundwater contamination
VES curve amplitude
Resistivity ratio
url http://www.sciencedirect.com/science/article/pii/S2950263224000589
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