Asian Review of Environmental and Earth Sciences

The level of contamination of Orashi River by total petroleum hydrocarbons were investigated through the collection of surface water samples and sediment samples from four locations along the river. Determination of the level of contamination was done with the use of gas chromatography-flame ionization detector after following laid down clean-up procedures. The results obtained showed that total petroleum hydrocarbons in the surface water were 10.913±2.2022mg/L, 7.645±2.683mg/L, 9.074±2.1654mg/L and 12.212±3.3034mg/L for stations 1, 2, 3 and 4 respectively with a mean value of 9.961±2.5885mg/L, while in the sediment samples concentration values recorded were 22.3925±5.2104mg/Kg, 35.1071±9.9652mg/Kg, 50.4431±15.9916mg/Kg and 29.3869±8.0410mg/Kg for stations 1, 2 3 and 4 respectively with a mean value of 34.3324±9.8021mg/Kg. The partition coefficient calculations revealed that the sediment phase is more stable for total petroleum hydrocarbons as compared to the water phase. The analysis of the randomly collected samples revealed that total petroleum hydrocarbons have contaminated the river and therefore adequate steps should be taken to remedy the present condition of the Orashi River in order to mitigate any probable rise in the quantity of total petroleum hydrocarbons in the river above allowable limit.