Hematological and Biochemical Changes in the Neotropical Fish Astyanax altiparanae after Acute Exposure to a Cadmium and Nickel Mixture

Ni and Cd are widely used together in the manufacture of cells and batteries. The incorrect disposal of these products can result in environmental contamination, posing risks to the organisms exposed to these contaminants. However, the effects of the mixture of Ni and Cd in freshwater fishes are still unclear in the current literature, especially in relation to biomarkers of oxidative stress. Thus, the objective of the current work was to compare the sublethal effects caused by the mixture of cadmium (Cd) and nickel (Ni) with the effects of these metals individually, in the fish Astyanax altiparanae . The animals were exposed for 72 h to 20 μg L -1 of Cd, 1.5 mg L -1 of Ni, or a mixture of these two metals at the concentrations mentioned. After exposure, tissue samples were collected to evaluate hematological and plasma parameters, biomarkers of oxidative stress in the gills, and acetylcholinesterase (AChE) activity in brain and muscle. Exposure to the mixture caused alterations that were not observed in the groups exposed to the metals individually, such as increased activity of catalase and glutathione-S-transferase, and a reduction in AChE activity in the brain. Thus, we concluded that exposure to the mixture of Cd and Ni is more harmful to A. altiparanae than exposure to these metals separately.