Resumen
Samples were collected from the water and sediment columns of the Orashi River from December 2019 to June 2020 at intervals of two months and then analyzed for the concentration of total petroleum hydrocarbons and the origin of the petroleum hydrocarbons pollution in the river. Laboratory pretreatment of samples, extraction procedures and gas chromatography clean-up methods were properly followed before sample analysis and determination of total petroleum hydrocarbons components Gas Chromatography-Flame Ionization Detector (GC-FID). Total petroleum hydrocarbons components recorded were from C8-C40 fractions in the water and sediments of the river. The concentration values of total petroleum hydrocarbons in the water of the river lied between 5.844-16.888 mg/L and in the sediments the value recorded ranged between 16.655-50.504mg/Kg. The source diagnostic ratios and indices applied such as C15-C19 odd numbered hydrocarbons, C18-C22 even numbered hydrocarbons, LMW/HMW, LHC/SHC, C31/C19 ratios and the CPI and ACL indices revealed the source of total petroleum hydrocarbons pollution in the river was from both natural and anthropogenic input. Therefore control and regulatory measures need to be put in place to checkmate the activities that bring about total petroleum hydrocarbons present in the river so that human health and aquatic flora and fauna will be preserved within the river and its environs.