Application of Gas Chromatography-Mass Spectrometry in Environmental Monitoring of Industrial Effluents in Rivers State

Industrial effluents from petroleum refining, petrochemical processing, and manufacturing facilities in Rivers State, South South Nigeria, contain a complex mixture of organic contaminants that require sophisticated analytical techniques for comprehensive characterisation. This study applied gas chromatography coupled with mass spectrometry for the identification and quantification of priority organic pollutants in industrial effluents from three facilities in Port Harcourt, including a petroleum refinery, a paint manufacturing plant, and a plastics processing unit. Effluent samples were collected monthly over six months, extracted by liquid-liquid partitioning using dichloromethane, and analysed using a calibrated GC-MS system. Internal standards were used for quantification. Over 120 organic compounds were identified across samples, including benzene, toluene, ethylbenzene, xylene, naphthalene, phenol, polychlorinated biphenyls, phthalate esters, and petroleum hydrocarbon homologues. Total organic contaminant loads in the refinery effluent ranged from 84 to 347 mg/L. Benzene concentrations in 30 percent of refinery samples exceeded the WHO aquatic guideline value of 0.01 mg/L. Phthalate esters from the plastics facility were detected at ecologically relevant concentrations. Temporal variation in contaminant profiles reflected changes in process operation and seasonal rainfall dilution. The analytical data obtained from this GC-MS approach provide a comprehensive fingerprint of the contamination burden and identify gaps in existing effluent pre-treatment. The study recommends adoption of GC-MS as a standard regulatory monitoring tool for industrial effluent characterisation in Rivers State.

Keywords: gas chromatography-mass spectrometry, industrial effluents, organic pollutants, environmental monitoring, Rivers State