A critical review on the biological impact of natural organic matter on nanomaterials in the aquatic environment

Nanomaterials (NMs) are able to interact with natural organic matter (NOM) such that NOM is adsorbed on the surface of NMs to form an ecological corona (eco-corona). The formation of an eco-corona can greatly influence the behavior, risk and fate of NMs in the environment. A systematic understanding of the impacts of an eco-corona on the hazards of NMs is crucial for NMs risk assessment in the aquatic environment. Herein, the mechanisms of the formation of an eco-corona were reviewed based on the representative literatures and their generality was discussed on the basis of the type of NMs, the type of NOM and the environmental conditions. The effects of an eco-corona on the bioaccumulation and toxicity of NMs for aquatic organisms were systematically discussed through reported studies. The results showed that an eco-corona could alter the toxicity of NMs by changing the dissolution of NMs, adhesion of NMs and the damages to bio-membranes, internalization, and the generation of NMs-induced reactive oxygen species. The dual effects of an eco-corona on the toxicity/accumulation of NMs were widely present because of the complex molecular composition of NOM, the diverse types of NMs, and the variable environmental conditions. The effects of an eco-corona on the fate and the effects of other pollutants (such as metals and organic pollutants) were also carefully reviewed. The results showed that more research is needed to investigate the effect of an eco-corona through the development of novel techniques, mathematical modeling, and mesocosm studies.Environmental Biolog