Physico-Chemical Transport of Volatile Organic Compounds (VOCs) from Gas Flaring into Surface Waters of Ogoniland, Rivers State, Nigeria

Abstract

Gas flaring continues to be a persistent source of environmental pollution in the Niger Delta, releasing volatile organic compounds (VOCs) that contribute to atmospheric degradation and aquatic contamination. This study assessed the physico-chemical transport of VOCs from gas flaring into surface waters of Ogoniland, Rivers State, Nigeria. Surface water samples were collected from five stations located at varying distances (0.5–2 km) from active gas flare sites during wet and dry seasons. Standard analytical procedures were employed to determine physico-chemical parameters, while VOCs, including benzene, toluene, ethylbenzene, and xylene (BTEX), were quantified using gas chromatography–mass spectrometry (GC–MS). Results revealed that temperature, pH, electrical conductivity (EC), total dissolved solids (TDS), and dissolved oxygen (DO) varied significantly (p < 0.05) between stations and seasons. The highest VOC concentrations were recorded at stations closest to flare points, with total VOCs ranging from 0.021–0.086 mg/L in the wet season and 0.039–0.102 mg/L in the dry season. Correlation analysis indicated that VOC levels were positively associated with temperature and EC but negatively correlated with DO, suggesting that volatilisation, adsorption–desorption, and atmospheric deposition govern VOC transport in the aquatic system. The findings highlight that continuous gas flaring promotes the mobilisation and persistence of toxic organic compounds in surface waters, posing potential ecological and health risks to communities relying on these water sources. The study underscores the need for stricter regulation of gas flaring activities and continuous environmental monitoring to safeguard aquatic ecosystems and public health in the Niger Delta.