Interactions between micro(nano)plastics and natural organic matter: implications for toxicity mitigation in aquatic...

Plastics have significantly contributed to modern conveniences owing to their ease of use, stability, and adaptability. However, the fragmentation of plastics into microplastics (MPs) and nanoplastics (NPs) poses significant environmental risks. These micro(nano)plastics (MNPs) can adsorb various pollutants and pathogens, potentially posing significant ecological risks. This review critically examines the natural organic matter (NOM) in mitigating the toxicity of MNPs in both marine and freshwater species. Evidence suggests that NOM facilitates the formation of an eco-corona (EC) on MNPs, thereby reducing toxicity. Reduced toxicity attributed to EC formation has been observed in various freshwater species, such as Danio rerio and Daphnia magna, as well as marine species, including sea urchins, European sea bass, and marine algae. The presence of natural organic matter (NOM), particularly fulvic acid (FA) and humic acid (HA), significantly mitigates the toxic effects of MNPs, with HA exhibiting a strong protective effect. The interactions between MNPs and NOM, including the formation of the EC, which encompasses a protein corona component, are pivotal in understanding toxicity mitigation in aquatic environments. This review highlights the need for further research to elucidate the interactions between MNPs and NOM, and their role in mitigating toxicity across marine and freshwater ecosystems.