Bioremediation of Crude and Refined Oil-Polluted Fresh Water Using Chlorella vulgaris Isolated from a Pond

Crude and refined oil contamination of the aquatic environment is one of the major environmental problems that lead to unmanageable loss of biological life that impacts negatively on global economy particularly in the areas of petroleum production and transportation. Bioremediation potential of Chlorella vulgaris isolated from a pond in Uwani, Enugu State, Nigeria was studied using standard methods. The organism utilized crude oil heavily, kerosene moderately and petrol minimally as shown by the varying degree of turbidity produced during fourteen days of growth in mineral salts- oil medium. Biodegradation experiment was carried out for forty-two days and the results showed that there was a decrease in pH and an increase in the absorbance of the mineral salts - oil medium. The percentage of degradation of the crude oil, kerosene and petrol by the organism was 80%, 70% and 60% respectively. There was a reduction in the peak numbers and peak areas of the gas chromatograms of the total petroleum hydrocarbons and polyaromatic hydrocarbons of the residual crude oil as well as the residual kerosene and petrol. This work therefore indicated that the microalga C. vulgaris can be used for the bioremediation of crude and refined oil - polluted aquatic environments.