Christopher Onyemaechi Ezike, Agbo, A.N, Uwadiegwu, N.C
The study investigated the acute toxicity of the lethal doses and the use of Moringa, Moringa oleifera leaf extract MLE to ameliorate the toxicity of cassava, Manihot esculenta waste water CWW 0.01 mg/L, 0.02 mg/L, 0.03 mg/L, 0.04 mg/L, 0.05 mg/L and 0.00 mg/L of clean water exposed to 360 fingerlings of Clarias gariepinus 2.00 ± 0.02 g, 2.50 ± 0.10 cm in a static fisheries laboratory bioassay, Enugu lat. 7.4 N; 80 7’5 and long 60 8’E. 70 6’ W for 96 hours. The acute concentrations were ameliorated with 2.00 mg/L MLE and replicated thrice in 18 plastic bowls. Exposed fish indicated stress characteristics such as erratic movements, air gulping and immobilization, loss of balance and period of quiescence before death. Dose dependent ventilation rate and tail beat frequency were indicated at the onset of the experiment but declined towards the end of the exposure period. The 96 hours LC50 was determined to be 0.02 mg/L but was ameliorated to be 0.045 mg/L when MLE was added. The test toxicant not exceeding the safety value of 0.0002 mg/L should not be allowed into the aquatic environment meant for the culture of fingerlings of the test fish except where 2.00 mg/L MLE is applied to reduce the toxicity to 0.00045 mg/L of CWW. The characterization and quantification of the coagulant properties of MLE are suggested in further studies.