PHYTOTOXICITY ASSESSMENT OF WATER SOLUBLE FRACTIONS OF REFINED PETROLEUM PRODUCTS USING MICROALGAE

摘要

A study on the effect of water soluble fractions (WSF) of petroleum products (diesel, kerosene and petrol), on two test microalgae - Desmodesmus quadricauda and Eudorina elegans -was conducted in the laboratory for 14 days using various concentrations(0%, 10%, 25%, 50%, 75% and 100%). The growth response was measured spectrophotometrically using optical density at 680 nm. A general assessment indicates that both microalgae used were impaired by the high concentrations of WSF of these fuel oils, while lower concentrations stimulated growth. For Eudorina elegans, maximum growth was obtained at 10% in all fuel oils except kerosene, where maximum growth was obtained at 25%. For Desmodesmus quadricauda, maximum growth was recorded at 10% in diesel, 25%in kerosene and 50% in petrol. The study revealed that both test microalgae had their minimum growth and were highly inhibited in 100% concentration of water soluble fractions of the fuel oils. E. elegans was more inhibited than D. quadricauda in all concentrations of water soluble fractions of the fuel oils except at 100% concentration, where D. quadricauda was more inhibited. Statistically, there was significant difference between the various concentrations of the WSF of most fuel oils investigated except between control and 10% of E. elegans in petrol and between 10 and 25% of both test algae in diesel.