Abstract

Polycyclic Aromatic Hydrocarbons (PAHs) are among the listed persistent organic compounds (POP) which are pollutantsof environmental concern due to their toxicity. This study evaluated soxhlet and ultrasonic extraction methods using athree-solvent system (acetone+dichloromethane+n-hexane) in order to compare the ability of the techniques to extractselected PAHs in raw coals collected from a coal mine in Okobo-Enjema, Nigeria. Then, binary solvent mixtures consistingof acetone+dichloromethane; dichloromethane+n-hexane; and acetone+n-hexane, were compared with the ternary solventsystem for their ability to extract the target PAHs by soxhlet extraction method. The extracts were quantitatively analysedfor sixteen PAHs using Gas Chromatography-Mass Spectrometer (GC-MS). Sonication extraction method extracted highernumber of PAHs, required fewer amount of solvents, shorter time of extraction and less energy consumption compared tosoxhlet extraction, which extracted higher amount of the target PAHs. The total amount of PAHs determined ranged from0.02 mg/kg to 0.20 mg/kg in the various solvents’ mixtures. The ternary mixture extracted larger quantities of the targettoxic PAHs. This report will assist in the choice of analytical methods and solvent systems for environmental studies.

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