Acute Toxicity and Histopathological Effects of Engine Oil on Sarotherodon melanotheron.
The lethal effects of engine oil effluent on Sarotherodon melanotheron was investigated using pathologic lesions in the gill, kidney and muscle. Five concentrations of 0.035, 0.07, 0.14, 0.21 and0.28 ml/l for 96hrs were used for the experiment. The randomized ANOVA for toxicity of the extract against S. melanotheron showed that there were significant differences in the test. The lethal concentration LC that caused 50% 50 mortality was approximately 1.12mg/l of the engine oil. Lesion observed in the gill epithelium exposed to at the different concentrations of the engine oil were dose dependent with the highest effluent concentration inducing the highest damages which include mild congestion, severe congestion and calcification of the gill. The Kidney tissues of S. melanotheron exposed to the engine oil effluents showed severe congestion, inflammation, cytoplasmic vacuolations which may have been due to glycolysis leading to microsomal and mitochondrial dysfunction. While the muscle tissues were normal even after the exposure. The entire test organism in the control showed inappreciable or no histologic degradation while their staining patterns and cellular arrangement remain unaffected. The result obtained showed that engine oil effluents pose a serious damage to S. melanotheron and was observed that acute concentration of engine oil effluents have histopathological effects on aquatic organisms. It can be deduced that indiscriminate discharge of industrial effluents into water bodies can induce damage to the tissue and organ, which might make the fish vulnerable to diseases and eventually lead to death of prominent edible species of the aquatic environment, Therefore there is need for the adoption of proper effluent treatment technology which would ensure proper treatment of industrial effluent and check the recurrence of oil spillage. Indiscriminate exposure of aquatic organisms to engine oil effluent should be discouraged.