Assay of Polycyclic Aromatic Hydrocarbons in Soils from Selected Areas in Ughelli and Its Environs, Delta State, Nigeria

Abstract

The occurrence of polycyclic aromatic hydrocarbons was investigated in primary sources (pure hydrocarbons) and secondary sources (soils) from selected areas suspected to be contaminated with hydrocarbons in Ughelli and its environs, Delta State, Nigeria. Samples were quantified with gas chromatography equipped with mass spectrometer detector (GC-MSD) after extraction and clean up of the extracts with dichloromethane. The concentrations of Σ17 polycyclic aromatic hydrocarbons ranged from 814 to 103100 μg kg-1 in primary sources and 84 to 796 μg kg-1 in secondary sources respectively. For the secondary sources, the decreasing order of PAHs based on locations followed the order: Mechanic Workshop Soil > Generator Compound soil > Flow-station Soil > Filling Station Soil > Motor Way Soil. The lower molecular weight (2-3 rings) PAHs and non-carcinogenic PAHs were the predominant PAHs in these soils. The isomeric ratios and principal component analysis used for source apportionment indicate that the PAHs in the secondary sources were from combustion processes of biomass and fossil fuels such as wood and coal.