Determination of acute toxicity and the effects of sub-acute concentrations of CuO nanoparticles on blood parameters in Rutilus rutilus

Objective(s): Copper oxide nanoparticles have different industrial applications so it is inevitable that nanoparticulate products finally find their way into aquatic ecosystems. Nevertheless there is little information available about their effects on some of edible fish. The present study aims to determine the acute toxicity and evaluate the effect of two subacute concentrations (50 and 70% 96 h LC50) of CuO-NPs on some hematological and biochemical parameters of R. rutilus. Materials and Methods: 225 healthy specimen of R. rutilus (mean weight 5.52 +/- 1.2 g; mean length 6.20 +/- 0.2 cm) were transported to the laboratory. In order to prepare the stock solution, CuO-NPs was dispersed in pure water with ultrasonication (50-60 kHz) for 15 min every day before dosing. At first, R. rutilus was exposed to CuO-NPs to determine the lethal concentration (LC50) value. Following acute test, fish were treated with sub-acute concentrations of CuO-NPs (50 and 70% 96 h-LC50 at) with one control group (no CuO-NPs) for a week to determine the changes in the level of some plasma hematological and biochemical parameters. Results: The 96 h-LC50 values of CuO-NPs was 2.19 +/- 0.003 mg/l. R. rutilus exhibited significantly lower RBC count, Hb and Hct values and a significant increase in the WBC numbers, MCH, MCHC and MCV indices (p<0.05). Low glucose and higher cortisol content in plasma were observed in the fish exposed to CuO nanoparticles than those in control group (p<0.05). Conclusion: These alterations indicate R. rutilus sensitivity to CuO-NPs and changes in blood parameters would be a useful tool for measurement early exposure to CuO nanoparticles.