With the increase in human population and the increasing use of nanoparticles, nanopollution of aquatic ecosystems have increased and this condition will lead to environmental and health concerns for aquatic organisms as well as humans as aquatics consumers. Thus, the aim of present research was to assess the bioaccumulation potential of Zn in the gills and hepatopancreas of freshwater crayfish (Astacus leptodactylus) following exposure to ZnO NPs or zinc ions. Adult crayfish were exposed to either a high non-lethal (500 μg/L) or a low environmental relevant concentration (0.05 μg/L) of ZnO NPs and ZnSO4.7H2O. Following 14 days of waterborne exposure, gills and hepatopancreas were dissected and after acid digestion, Zn content were measured by graphite furnace atomic absorption spectrophotometer. The results of one-way ANOVA indicated that Zn accumulation differed significantly among tissues in different concentration compared with the control group (p < 0.05). Regardless of the concentration or type of exposure materials, Zn bioaccumulation in the hepatopancreas was higher than the gill. Moreover, Zn accumulation in both of the gill and hepatopancreas tissues were found to follow the order of 500 μg/L Zn ions> 500 μg/L ZnO NPs > 0.05 μg/L Zn ions > μg/L mg/l ZnO NPs> control. According to our results, although both ZnO NPs and Zn2+ have the potential to accumulate, at the same concentrations, the accumulation of ionic zinc was higher than nanoparticulate form both in the gill and hepatopancreas tissues of narrow-clawed crayfish. Further studies are recommended to comparing aquatic toxicity of ionic and nanoparticulate forms of heavy metals.
