Iron oxide nanoparticles to an Indian major carp, Labeo rohita: Impacts on hematology, iono regulation and gill Na+/K+ ATPase activity

In this study, the chronic toxicity effects of iron oxide (Fe2O3) nanoparticles (NPs) (500 mg l−l) on certain hematological, ionoregulatory and gill Na+/K+ ATPase activity of an Indian major carp, Labeo rohita were estimated for a period of 25 days under static bioassay. A significant increase in hemoglobin (Hb) content, red blood cell (RBC) count and hematocrit (Ht) value was noticed throughout the study period when compared to control groups. In contrast, mean cellular volume (MCV), mean cellular hemoglobin (MCH) (except on 5th day) and mean cellular hemoglobin concentration (MCHC) levels and white blood cell (WBC) counts were found to be decreased during the above study period. Fe2O3 NPs also caused alterations in iono regulation resulting in hyponatremia (Na+), hypochloremia (Cl−) (except on 5th day) and hypokalemia (K+) (except up to 15th day). A biphasic trend in gill Na+/K+-ATPase activity was noticed during the above treatment period. Our results demonstrate that high Fe2O3 NP concentrations in the aquatic environment may have adverse physiological effects on fish. These data may be useful to assess the environmental risk posed by NPs. However the toxicity of various sizes of the nanoparticle could be evaluated using different aquatic organisms.