Exposure risks to polycyclic aromatic hydrocarbons by humans and livestock (cattle) due to hydrocarbon spill from petroleum products in Niger-delta wetland

In this study, the human and livestock (cattle) health risks of exposure to polycyclic aromatic hydrocarbons (PAHs) in a wetland of Obuaku, Abia State Nigeria contaminated by hydrocarbon spill due to incidents of hydrocarbon theft and pipeline vandalization were assessed. Gas chromatography-flame ionization detector and gas chromatography-mass spectrometry were employed in analyzing the TPH and PAHs respectively. The contaminated soil was delineated into sub-locations AOC-1, AOC-2, AOC-3, AOC-4, AOC-5 and AOC-6 to reflect the discrete patches (areas) of the contaminated site and for effective planning of remedial actions. The concentration of the PAHs in AOC-4 was insignificant but was quite significant in AOC-1, AOC-2, AOC-3 and AOC-6. The average percentage distribution of the PAHs in all the sites is 9.8% carcinogenic and 91.2% non-carcinogenic. The ecological risk assessment revealed that only sub-location AOC-4 contains PAH to a level of insignificant biological impairment while sub-locations AOC-1, AOC-2 and AOC-6 contain PAHs that pose the highest ecological risks. The assessment of health risk exposure to carcinogenic and non-carcinogenic PAHs indicated insignificant risks for all sub-locations whereas the assessment of health risks using PAH toxicity method indicates that only sub-locations AOC-1, AOC-2 and AOC-6 were toxic. These sub-locations were also found to be of significant health risks to livestock (cattle). Robust empirical models describing the relationships between TPH and any of the risk parameters were generated such that TPH can be used in predicting the risk parameters for spillage peculiar to petroleum products.