HEAVY METAL CONTAMINATION AND ASSOCIATED ECOLOGICAL RISKS ON SOILS AROUND GAS FLARING SITE, IBENO L.G.A
Abstract
Heavy metal contamination of soils represents a significant environmental and public health concern, particularly in regions exposed to intensive oil and gas activities. This study assessed the concentration, contamination levels, and ecological risks of selected heavy metals in agricultural soils surrounding a gas flaring site in Ibeno Local Government Area, Akwa Ibom State, Nigeria. Soil samples were collected at distances of 100 m, 200 m, and 500 m from the flare stack and analysed for Lead (Pb), Cadmium (Cd), Chromium (Cr), Arsenic (As), Manganese (Mn), Mercury (Hg), Nickel (Ni), Copper (Cu), Zinc (Zn), and Vanadium (V) using Atomic Absorption Spectroscopy (AAS). Contamination indices, including Contamination Factor (CF), Degree of Contamination (Cd), Pollution Load Index (PLI), and Geo-accumulation Index (Igeo), were employed to evaluate pollution status and ecological risks. Results revealed that heavy metal concentrations were highest at 100 m and decreased with increasing distance from the flare stack, indicating a strong influence of gas flaring emissions. Cadmium, Mercury, Lead, Arsenic, Copper, and Vanadium exceeded recommended FAO/WHO limits at specific locations. Cadmium exhibited the highest contamination factor and geo-accumulation index, signifying severe contamination and substantial ecological threat. The Degree of Contamination (Cd = 16.08) and Pollution Load Index (PLI = 3.45) confirmed considerable pollution of the study area. The findings highlight significant environmental and potential health risks associated with prolonged exposure to contaminated soils. The study underscores the need for continuous environmental monitoring, implementation of effective pollution control measures, and adoption of remediation strategies to mitigate heavy metal contamination in gas flaring environments.
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