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 Zeolitic Imidazolate Framework-8 (ZIF-8) is influenced by its concentration, with lower concentrations resulting in higher percentages of Zn2+ 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.