OCCURRENCE, SOURCE APPORTIONMENT AND PREDICTIVE MODEL OF POLYCYCLIC AROMATIC HYDROCARBONS IN A STREAM WATER OF A NIGERIAN COAL MINE AREA

Abstract

This study investigated the occurrence and levels of selected polycyclic aromatic hydrocarbons (PAHs) in stream water samples collected in two seasons from the vicinity of a coal mine. The organic content of the water samples were extracted by liquid-liquid extraction technique using a binary solvent system. The extracts were analysed for sixteen PAHs using Gas chromatography coupled with mass spectrometry (GC-MS). The range of the mean total concentrations of PAHs in rainy season stream water samples were 0.02-0.69mg/l; and 0.00 – 0.02 mg/l in the dry season samples. The rainy season water samples contained naphthalene, a low molecular weight PAH, while the dry season water samples contained benzo[a]pyrene and pyrene, which were high molecular weight PAHs. These PAHs are toxic, indicating health risk to the stream water consumers. The results of the PAH analysis were evaluated for source apportionment which revealed that the PAHs in the water samples were of mixed sources, petrogenic and pyrolytic. A simple model for predicting total PAH concentrations was proposed. This report provides baseline data which may assist in environmental regulations and control to protect the health of inhabitants of the studied area and for similar areas. Keywords: analysis, coal, extraction, GC-MS, PAHs, water.