Environmental fate, transport, impacts, and future perspectives of engineered nanoparticles in surface waters

The release of engineered nanoparticles (ENPs) into the environment has raised significant concerns due to technological advancements. These nanoparticles undergo dynamic transformations once emitted from various point and diffuse sources. Recent studies have highlighted the harmful impacts of ENPs, including metal oxide nanoparticles, carbon-based nanomaterials, and polymeric nanoparticles, on multiple organisms, raising important questions about their behavior and fate across different environmental compartments. However, gaps remain in our understanding of the environmental fate, fundamental mechanisms, and potential consequences of ENPs in aquatic systems. This critical review analyzes 249 peer-reviewed scientific articles published from 2018 to 2023, focusing on the transformation processes that influence ENPs' occurrence and pathways in water bodies. It examines physical, chemical, and biological processes, such as agglomeration, dissolution, sedimentation, and adsorption, which affect ENP dynamics, emphasizing the role of their physicochemical properties and environmental conditions in influencing these processes and their associated cytotoxicity. Furthermore, this study highlights the applications of ENPs while addressing future challenges, including long-term exposure, trans-generational effects, the fate of transformed by-products, and the need for international regulations regarding wastewater management containing ENPs. These findings underline the necessity for further research into the environmental and biological impacts of ENPs to promote sustainable practices.