Potential synergistic effects of microplastics and zinc oxide nanoparticles: biochemical and physiological analysis...

The present study aimed to evaluate the effects of microplastics (MPs) and Zinc Oxide nanoparticles (ZnO-NPs), both individually and in combination, on the crayfish, Astacus leptodactylus. A total of 360 crayfish were assigned to eight experimental groups, including control and treatment groups exposed to MPs (polyethylene, polystyrene, and polyvinyl chloride at 300 µg/L) and ZnO-NPs (5 µg/L), individually and combined. Biochemical analyses on the haemolymph revealed a significant increase in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, gamma glutamic transpeptidase activities, and glucose and cholesterol levels in crayfish exposed to MPs and ZnO-NPs. In contrast, butyrylcholinesterase activity was significantly decreased in all treatments compared to the control. Lactate dehydrogenase activity increased significantly in crayfish exposed to ZnO-NPs, alone or combined with MPs. Furthermore, thiol groups, total antioxidant levels, and glutathione peroxidase, glutathione reductase, catalase, and superoxide dismutase were significantly decreased, while malondialdehyde levels were increased. The integrated biomarker response (IBR) and radar plots highlighted a cumulative oxidative stress response, suggesting potential synergistic or additive interactions between MPs and ZnO-NPs.