Geo-Environmental Risk Assessment of Abandoned Petrol Stations in
Essien Udim Local Government Area, Akwa Ibom State
Bulus Simon1, Boma Aaron Philip2, Ibrahim Enoch3, Omorogieva Osriemen Evangelistal4
1Department of Environmental Science and Management Technology, Federal Polytechnic, Ukana
2Department of Environmental Science and Management Technology, Federal Polytechnic, Ukana Akwa
Ibom State, Ukana
3Department of Urban and Regional Planning, Federal Polytechnic, Ukana
4Department of Environmental Science and Management Technology, Federal Polytechnic, Ukana
Received: 06 November 2025; Accepted: 14 November 2025; Published: 21 November 2025
ABSTRACT
This study examines the contamination of soils and groundwater around abandoned petrol stations in Akwa
Ibom State, Nigeria, the study further evaluate associated environmental and health risks. Six sites were
purposively selected, and samples were analyzed for pH, Total Petroleum Hydrocarbons (TPH), lead (Pb),
nickel (Ni), and benzene using standard APHA and ASTM procedures. Descriptive statistics and Pearson
correlation were applied to quantify pollutant relationships. Results shows that, mean soil TPH (1575 ± 510
mg/kg) exceeded the DPR limit (100 mg/kg), indicating severe hydrocarbon pollution. Mean Pb (40.22 ± 11.7
mg/kg) and Ni (29.18 ± 9.3 mg/kg) were below regulatory limits but reflected anthropogenic influence.
Groundwater TPH (0.048 ± 0.02 mg/L) and benzene (0.017 ± 0.009 mg/L) exceeded WHO limits (0.05
mg/L;0.01 mg/L). Significant correlations existed between TPH and Pb (r = 0.87) and between benzene and Ni
(r = 0.76). Findings highlight hydrocarbon metal co-contamination and potential groundwater migration,
necessitating remediation and continuous monitoring.
Keywords: Abandoned petrol stations, Benzene, Groundwater pollution, Heavy metals, Soil contamination
INTRODUCTION
The petroleum hydrocarbons and their byproducts still continue to be one of the most widespread types of
environmental contaminants in the world, as they occur due to accidental spills, leaking storage facilities, and
normal losses at fuel retail and distribution stations(WHO, 2003; WHO, 2017). The high geo-mobility of most
hydrocarbon substances (especially benzene and other BTEX components) under favorable hydro-geological
conditions, combined with their toxicity, makes past contamination of fuel deposits a significant remedial and
health concern in both developed and developing countries (Fei-Baffoe, 2024; WHO, 2003). Guidelines on
drinking water and soil highlight the minimum permissible levels of volatile aromatics like benzene (guideline
value 0.01 mg/L) due to their carcinogenic risks and plume-forming properties in groundwater (WHO, 2003;
WHO, 2017).
The situation is especially severe in the oil producing and oil consuming nations with high concentrations of
petrol stations many of which are located near residential locations and shallow aquifers that make soil and
groundwater pollution more likely in case of corroding of tanks or as a result of poorly decommissioned
operation (Okop, 2012; IOSR, 2017). Recent regional monitoring has reported sustained overages of regulatory
levels of TPH and benzene around petrol stations and petroleum storage facilities, with hydrogeological
environments like sandy soils and shallow water tables enhancing downward movement into the groundwater
utilised in domestic supply (Fei-Baffoe, 2024; Agbor Metropolis study, 2025).
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