Phytoremediation of Diesel Contaminated Water DCW Exposed on Clarias gariepinus Using Moringa Seed Extract MSE as the phytoremediant

Abstract

Phytoremediation of diesel contaminated water (DCW) for freshwater fish Clarias gariepinus (12.6 ±1.4g and mean length 8.6 ± 0.7cm) was conducted at the research farm of the Enugu State University of Science and Technology Enugu. 180 juveniles were purchased and acclimatized for 7 days. A 24-hour range finding test determined the LC50 value of 1.2 mg/l DCW. A 96-hour static bioassay acute toxicity experiment was then conducted in plastic tanks with 10 fish in each, and diesel of different concentrations. Mortality rate was observed in the various test concentrations. The LC50 concentration was 0.12 mg/l, improved to 0.30 mg/L with MSE-treated diesel. Histopathology of the gills of affected fish showed elevated damage, necrosis, telangiectasia and oedema in DCW exposed fish, but limited damage in MSE-treated DCW exposed fish. The results of the experiment showed that diesel has detrimental effects on C. gariepinus and could cause high mortality at higher concentrations. Moringa seed extract (MSE) was used as a phytoremediant to ameliorate the mortality and gill histological damages of the experimental fish. Therefore, diesel contaminated water should be ameliorated to a safety level of 0.003 mg/l with MSE to protect fish species and other aquatic organisms.