Short-term safety and risk evaluation of engine oil enriched by high concentrations copper nanoparticles on the skin

Abstract Objective(s): Copper nano particles are added to ordinary engine oil as an additive to reduce friction and repair damaged surface under friction conditions. However, it is still unclear what environmental effects such a compound might have on conventional engine oils and its toxicity in different animal species has not been determined. The aim of this study is to investigate the effect of short-term exposure of large amounts of nano sized particle-enriched engine oil to transcutaneous animal model on earthworms in order to evaluate its hazards in human contact. Methods: Screening test (filter paper contact test) involves applying earthworms on the paper to identify potentially toxic chemicals in the soil for earthworms, and artificial soil testing involves holding earthworms in samples of predefined and precise soil. In both tests a range of different concentrations is used. In artificial soil testing the results of loss is obtained 7 and 14 days after the experiment. In the flat paper test the losses are checked 24 and 48 hours or if required up to 72 hours later. Results: The lethality rate of the engine oil used at a concentration of 1.25 ml or higher was obtained from fresh engine oil containing nano-copper at ۲۴ Hours and ۴۸ was significantly higher (p <0.001). Conclusion: The toxicity of a new engine oil is higher than that of a new engine oil containing copper nanoparticles, but in the case of used engine oil, the toxicity of nano-oil is higher than that of conventional oil.