Ecotoxicity and interactions of micro- and nano-plastics in aquatic environments: advancing towards standardized mitigation approaches

Abstract

This study reviews the various micro- and nano-plastic (MNP) pollution, which demands immediate mitigation strategies in aquatic ecosystems to ensure an effective, scalable, and sustainable solution. The focus is summarising the physical, chemical, and biological processes to remediate MNP contamination. Physical techniques such as adsorption, flotation, and filtration are also considered representative strategies. Pollutants like biochar and carbon nanotubes can be removed by adsorption in plants. However, there is a risk of secondary pollution from this. Advanced filtration methods, such as sand filtration and membrane bioreactor, can achieve very high removal efficiency, but problems with membrane fouling limit scalability. Flotation holds tremendous potential if the right conditions are implemented. It also includes the chemical degradation methods (polar media like hydrogen peroxide and advanced oxidation processes (AOPs) and thermal degradation. Some AOPs rely on reactive species to degrade plastics, but they typically follow an energy-intensive route, whereas thermal degradation can decompose plastics with its own environmental cost. A molecular approach involving biological remediation, involving microbial and enzymatic degradation, is perceived as an environmentally friendly solution. Organisms with promising plastic-degrading abilities include Pseudomonas aeruginosa and Bacillus cereus , genetically engineered microorganisms, and fungal treatments. Moreover, the degradation of MNPs plays a substantial role in microbial biofilms. Nanotechnology is a potential supplement to MNP remediation processes, especially engineered nanoparticles. However, the study highlights the need for further research to optimise these methods, improve scalability, and ensure environmental safety, recommending a multi-faceted approach to ensure the effective and sustainable mitigation of MNP pollution.