Forensic, Aliphatic and Polyaromatic Hydrocarbons Assessment of Oil Polluted Soils from Selected Oil-Producing Communities in Ughelli Environs, Delta State, Nigeria

The objective of this paper is to examine the forensic, aliphatic and polyaromatic hydrocarbons of oil polluted soils from selected oil-producing communities in Ughelli Environs, Delta State, Nigeria using appropriate standard methods. The result of this study revealed variance in the n-alkane distribution in primary samples amongst the carbon number distribution ranges; C8 -C 12, C 13 -C 35 and C 36 -C 40 in the primary samples, C 13 -C 35 had the highest concentration. These ranges of the primary samples were similar to soil from secondary samples (Okpare-Olomu). The result revealed that the studied soil from secondary samples (Okpare-Olomu) was highly polluted with n-alkane concentration based on the UNEP guideline value of 10,000 mg/kg. Source diagnosis revealed that the sources of the n alkanes were from petrogenic origins specifically from Eruemukohwarien oil field thus Okpare Olomu soil samples are forensically significant to the primary sample (Eruemukohwarien oil field). Though in different concentrations, the result shows a similar PAH distribution in Iwhrekan and Ewu-Urhobo Soil samples. The total PAH concentration in the soil was within the recommended PAH contamination limit in soils. A large presence of carcinogenic (4-6 rings) PAHs was observed in all of primary samples as well as the secondary sample (Okpare-Olomu). The rest of the secondary soil samples had a pre-dominance of low molecular weight (2-3 rings) PAHs in minute quantities, indicating that the soils were not contaminated with carcinogenic PAHs.