Characterization and Correlation of Aliphatic Hydrocarbons in Oil Polluted Waters of Bonny Local Government Area, Rivers State

Abstract

Forensic chemical analyses was used to characterize, determine the source and correlate aliphatic hydrocarbons (AHCs) in water samples collected from Bonny L.G.A, Rivers State. AHCs were extracted from the water samples with n-hexane in a separatory funnel, clean-up achieved by column chromatography using n-hexane and analysis by Gas Chromatography Flame Ionization Detector (GC-FID). The GC chromatogram showed well resolved AHC peaks which distributed from nC9 –nC40. The GC chromatograms of AHCs, with a wide range of low molecular weight hydrocarbons, indicate minimal biodegradation of the oil hydrocarbons in the samples. CPI values from 0.68 to 0.78 for BY-A1, BY-A3, BY-A4 and 0.97 for BY-A2 suggest two sources of oil hydrocarbons. Calculated Pr/Ph ratios showed BY-A1 (2.08), BY-A3 (2.00) and BY-A4 (2.20) were derived from mixed marine and terrestrial source deposited in suboxic environment, while BY-A2 (3.70) was mainly terrigenous source in an oxic environment. A cross-plot of Pr/n-C17 and Ph/n-C18 ratios also showed a tight cluster for samples BY-A1, BY-A3 and BY-A4 which were degraded with sample BY-A2 separate and slightly degraded. Results from this study revealed that the spilled oil was derived from mixed organic sources deposited in an oxic environment with different oil input from external sources showing more terrestrial contribution.