Source Tracking and Carcinogenic Risk of Polycyclic Aromatic Hydrocarbons in Contaminated Farmlands from Egi, Niger Delta, Nigeria

The levels of Polycyclic Aromatic Hydrocarbons (PAHs) in contaminated farmland soil from three oil-producing communities (Oboburu, Obagi, and Ogbogu) in Egi, Niger Delta were assessed for variability, origin and health risks. The result showed that tPAHs of Oboburu were 1344±1685 mg/kg for carcinogenic while BaP (257.3±270.5 mg/kg) had the greatest value. Obagi had 4154±3461 mg/kg for cPAHs with BkF (861.5±543.7 mg/kg) having the greatest amount. Ogbogu was 354.7±360.7 mg/kg for total cPAHs while BgP (104.1±141.8 mg/kg) had highest amount. The dominant PAHs were BbF, BkF, DbA, BaP, IdP and BgP. The principal component analysis (PCA) indicated that the PAHs were majorly of pyrogenic and petrogenic origin. The predicted risk due to PAHs in soil for children showed tPAHs was 1.68E-2, with high risk for BaP (9.05E-3), IdP (5.05E-3), BbF (1.63E-3) and BkF (1.04E-3), while the adults estimation showed tPAHs was 1.13E-2 and high risk were for BaP (2.30E-3), IdP (1.08E-3) and BkF (2.57E-4). These values are more than the limit of the US EPA risk management criterion (10-6 to 10-4) where management decisions should be considered. The trend indicated that their presence in the environment makes it unsafe for the dwellers.