Carcinogenic Risk Assessment of Polycyclic Aromatic Hydrocarbons in Water From Qua Iboe River Estuary South South Nigeria

This study was conducted to determine the levels of carcinogenic and non-carcinogenic polycyclic aromatic hydrocarbon (PAHs) in water from Qua Iboe river estuary (QIRE), Ibeno-Nigeria and their carcinogenic health risk via ingestion of water from the river. \ Water samples were collected from five designated stations and one reference station along QIRE during the dry and wet seasons and analysed for PAHs using gas chromatography with flame ionization detector (GC/ FID). Carcinogenic health risk assessment was computed using models recommended by USEPA. Concentration for total PAHs ranged from 6.403E-04 (for the control) to 5.986E-02 mg/l.The total PAHs and total carcinogenic PAHs (ΣC-PAHs) in water at all the sites except the control sites were higher than the standards for European Union and WHO. Values of Benzo(b) pyrene (B(b)F) and Indeno( 1,2,3-cd)pyrene (Ind(1,2,3-cd)P) at all the sampling sites for both seasons were above the WHO standard for individual PAHs in coastal and surface water. Carcinogenic risk (CR) values indicated potential risk for B(b)F and Ind(1,2,3-cd)P via ingestion of water and the total CR values at all the sites were above the regulatory limit. This study revealed detectable quantities of PAHs in water at all the sampling sites for both seasons with potential carcinogenic risk specifically for B(b)F and Ind(1,2,3-cd)P and health risk resulting from possible synergistic effect of all the C-PAHs. National legislation to minimise gas flaring and the use of advance PAH treatment technology to minimise the level of pollution of the estuary is recommended.