Assessment of Polycyclic Aromatic Hydrocarbons in Soils from Selected Areas in Agbarho Communities, Delta State, Nigeria

Abstract

Wisdom Ivwurie and  Gabriel A. Akindeju

Polycyclic aromatic hydrocarbons (PAHs) are organic pollutants of environmental interest due to their established carcinogenic and mutagenic characteristics. In this study, PAHs occurrence in soil within some selected areas in Agbarho community, Delta State, Nigeria was assessed using gas chromatography equipped with a mass spectrometry detector (GC-MSD) after extraction and clean-up of the extracts with n-hexane/dichloromethane. The observed concentrations of ∑17 PAHs in the soils ranged from 16 to 122 µg kg^-1, and followed the order: mechanic workshop > barbecue spot > motorway> filling station > traffic point. On the average, the occurrence of the individual PAH compounds followed the order: Naphthalene > Anthracene = Carbazole > Phenanthrene > Fluorene > Benzo(a) pyrene > Acenaphthene = Flouranthene = Pyrene > Benzo(b)fluoranthene = Benzo(k)fluoranthene while the occurrence pattern of the PAHs with respect to ring size increases with increase in the number of aromatic rings (i.e, 2-rings > 3-rings > 5-Rings > 4-rings). The lower molecular weight (2-3 rings) PAHs (and non-carcinogenic PAHs) were the predominant PAHs in the study soils. The isomeric ratios and principal component analysis used for source apportionment indicated that the PAHs in these soils originated from high temperature combustion of biomass and fossil fuels such as wood and coal as well as traffic emissions.