eng Oriental Scientific Publishing Company Biosciences Biotechnology Research Asia 0973-1245 2016-01-27 3 2 187 191 4361 article A. Olonisakin 1 A. O. Adebayo 2 M. O. Aremu 1 Department of Chemistry Nasarawa State University, Keffi, (Nigeria) Department of Chemistry Federal University of Technology, Akure, (Nigeria) The levels of iron, copper, lead, chromium, barium, zinc and calcium were determined in fresh, used and treated crankcase oil using standard technique. The three methods of treatment used gave different level of metal in the oil. The used sample from diesel engine (lorry) gave a high level of metals than that of gasoline oil (car). Butanol/Hydrocarbon method of treatment gave a relatively low level of iron and copper compared to other two methods (caustic soda/hydrogen peroxide and propanol/butanol) while propanol/butanol gave a very low level of lead. Crankcase oil should not be discharged indiscrimately, recycling is preferable because of its environmental hazard to human beings through bioaccumulation and biotransfer from terresial and aquatic plants and animals. https://www.biotech-asia.org/vol3no2/metal-concentrations-of-fresh-used-and-treated-crankcase-oil/ Crankcase; Butanol/Hydrocarbon; Propanol/Hydrogen peroxide; Propanol/Butanol; Environmental