ISPUB.COM The Internet Journal of Toxicology Volume 7 Number 2 1 of 7 The Hepatotoxic Effects Of The Water-Soluble Fraction Of Spent Lubricating Oil In Wistar Albino Rats K Patrick-Iwuanyanwu, G Ogwe, F Onwuka Citation K Patrick-Iwuanyanwu, G Ogwe, F Onwuka. The Hepatotoxic Effects Of The Water-Soluble Fraction Of Spent Lubricating Oil In Wistar Albino Rats. The Internet Journal of Toxicology. 2009 Volume 7 Number 2. Abstract This aim of this study was to evaluate the hepatotoxic effects associated with pollution caused by spent lubricating oil, a major pollutant in Nigeria on terrestrial organisms. The hepatotoxic effects of three concentrations (10%, 50% and 100%) representing low, medium and high concentration of the water-soluble fraction (WSF) of spent lubricating oil in wistar albino rats was investigated. The range-finding test of WSF of spent lubricating oil was determined to be higher than 100% concentration after 48 hours. Serum L-alanine aminotransferase (L-ALT), L-aspartate amino transferase (L-AST), alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) increased significantly (p≤ 0.05) after the administration of 2mL WSF of spent lubricating oil orally for 28 days. The order of increase was 100% >50% >10%. The WSF of spent lubricating oil was slightly acidic with a pH value of 6.7. Histopathological examination of the liver tissues revealed obliteration of sinusoids, macrovesicular fatty change, disorganized cords and enlargement of hepatocytes. The results suggest that oral administration of varying concentration of WSF of spent lubricating oil may cause an adverse effect on the function of the liver. INTRODUCTION The water-soluble fraction (WSF) constituents are dispersed particulate oil, dissolved hydrocarbon and soluble contaminants such as metallic ions¬¬ 1 .The components of spent lubricating oil that go into solution make up the WSF. They are taken up by living cells and are metabolized 2 . This is ecologically important because in event of an oil spill into aquatic habitat, this is absorbed by living organisms with serious effects on the ecosystem. Large amounts of spent lubricating oil are liberated into the environment when the motor oil is changed and disposed into gutters, water drains, open vacant plots and farmlands, a common practice by motor mechanics and generator mechanics 3 . The ubiquitous and pervasive nature of petroleum-derived hydrocarbons and the magnitude of their input to aquatic ecosystems are the two main motivating factors for research focused on their toxicity to terrestrial organisms. The fraction of oil that is most bioavailable to marine biota such as teleosts is the dissolved hydrocarbons, which include the polycyclic aromatic hydrocarbons (PAHs). The general importance of PAHs as a toxic component of petroleum-derived hydrocarbons is well established. Predicting the toxicity of these compounds is fraught with challenges, including dynamic chemical profiles, nonspecific and chemical- specific mechanisms of action, and variable intra- and inter species sensitivities. Moreover, because hydrocarbons from oil spills can persist in near-shore sediments for decades or longer 4 , investigations into toxicity need to incorporate long- term exposure regimes. The spent lubricating oil, otherwise called waste-lubricating oil or waste crankcase oil (WCO) obtained after servicing and subsequent draining from automobile, generators and industrial machines is disposed off indiscriminately, and adequate attention has not been given to its disposal 5 . Analytical procedures commonly used to assess contamination by petroleum products are determination of hydrocarbon fractions, total hydrocarbon and heavy metal contents. Edebiri and Nwanokwale 6 , reported that metals present in spent lubricating oil are not necessarily the same as those present in the unused lubricants. It has also been observed that most heavy metals like Va, Pb, Al, Ni and Fe that are below detection in unused lubricants oil gave high concentration values in used oil 7 . The disposal of spent lubricating oil into open vacant plots and farms, gutters and water drains is an environmental risk considering the water table in the South-South Region of Nigeria and shallow bore-holes dug to get water for domestic use 8 . The suspected major soil contaminant/pollutant was spent lubricating oil from engines and other machinery. Oil in soil makes the soil condition become unsatisfactory for plant