Revealing the synergistic impacts of ZIF-8 and copper co-exposure on zebrafish behavior, tissue damage, and intestine microbial community.

The application of metal-organic frameworks (MOFs) has garnered significant attention in contemporary research. However, the impacts of MOFs on aquatic environments remain largely unclear. This study revealed that the water stability of ZIF-8 is influenced by its concentration, with lower concentrations resulting in higher percentages of Zn release. At 10 mg/L, ZIF-8 significantly reduced zebrafish locomotor activity, with total swimming distance decreasing by approximately 40.5%. Oxidative stress and neurotoxicity markers, reactive oxygen species (ROS), and acetylcholinesterase (AChE) levels increased by 2.18-2.24-fold and 1.92-2.24-fold, respectively. Zebrafish ingestion of ZIF-8 was observed, with further analysis showing severe vacuolization and necrosis in tissues, as well as a significant increase in the relative abundance of Proteobacteria in the gut microbiota. Additionally, the study examined the toxicity of co-exposure to ZIF-8 and other pollutants. When ZIF-8 and copper (Cu) were simultaneously introduced, zebrafish survival rates dropped significantly to 79.2%. Co-exposure caused more severe behavioral impairments, with swimming distance reduced by approximately 53.0%, compared to individual exposures to ZIF-8 or Cu. ROS and AChE levels rose by 2.68-3.37-fold and 2.93-3.77-fold, respectively, while tissue vacuolization and necrosis became more pronounced. The relative abundance of Proteobacteria increased to 92.2%. This study provides critical insights into the environmental and ecological impacts of MOFs, emphasizing the necessity of considering these effects for their sustainable application.