The effect of spent engine oil on Guppies (Poecilia reticulata)

J.C. Onovo¹, P.G.C. Odeigah² and A. O. Ogaraku¹

¹Department of Biological Sciences, Faculty of Natural and Applied Sciences, Nasarawa State University P.M.B 1022, Keffi, (Nigeria) ²Department of Cell Biology and Genetics, Faculty of Science, University of Lagos, Akoko-Lagos, (Nigeria).

ABSTRACT: The effect of spent engine oil on fresh water Guppy (Poecilia reticulata) were studied by exposing fry to different concentrations of spent engine oil in aquaria. In the acute toxicity tests, LC50 of spent engine oil were 6.012, 1. 655, 2.162 and 2.723 at 24, 48, 72 and 96 hours respectively. This shows that the impacts are dose and time dependent with respect to marked reduction in mortality rate. Although, at sub-lethal concentrations of the test substance, there were considerably low mortality rates especially at lower concentrations of the substance. Histological studies carried out on the intestine and liver of treated P. reticulata showed that absorption of spent engine oil resulted in the swelling of the intestinal villi at concentrations of more than 1.0ml/l of test substance. More devastating impacts were caused by exposure to higher concentrations. Histological examination of the liver of the fish exposed to higher concentrations showed a distortion of the hepatic portal vein. The implications of the study are that pollution from spent engine oil results in the release of vast quantities of lethal and potentially genotoxic contaminants in the environment.

KEYWORDS: Spent engine oil; guppies; genotoxicity; acute; chronic toxicity

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