Nanoplastics are significantly different from microplastics in urban waters

Abstract

Microplastics (MPs) and nanoplastics (NPs) are ubiquitous and intractable in urban waters. Compared with MPs, the smaller NPs have shown distinct physicochemical features, such as Brownian motion, higher specific surface area, and stronger interaction with other pollutants. Therefore, the qualitative and quantitative analysis of NPs is more challenging than that of MPs. Moreover, these characteristics endow NPs with significantly different environmental fate, interactions with pollutants, and eco-impacts from those of MPs in urban waters. Herein, we critically analyze the current advances in the difference between MPs and NPs in urban waters. Analytical challenges, fate, interactions with surrounding pollutants, and eco-impacts of MPs and NPs are comparably discussed., The characterizations and fate studies of NPs are more challenging compared to MPs. Furthermore, NPs in most cases exhibit stronger interactions with other pollutants and more adverse eco-impacts on living things than MPs. Subsequently, perspective in this field is proposed to stimulate further size-dependent studies on MPs and NPs. This review would benefit the understanding of the role of NPs in the urban water ecosystem and guide future studies on plastic pollution management.

Keywords: Eco-impacts; Nanoplastics; Plastic pollution; Urban water.

Graphical abstract

Fig. 1

The highly different physicochemical properties of MPs and NPs in urban water systems.

Fig. 2

(a) Interactions of PS MPs and NPs with suspended sediment in water (Li et al., 2019); and (b) Heteroaggregation of PS NPs in various waters and in the presence of different abiotic pollutants (Oriekhova and Stoll, 2018).

Fig. 3

The inhibition mechanism of NPs on nitrogen removal in sequence batch reactors (SBR) (Zhou et al., 2022).

Fig. 4

Impacts of MPs and NPs on the oxidative status and gut microbiota in Oryzias melastigma (Kang et al., 2021).

Fig. 5

The impacts of NPs on the gut-brain axis. SCFA: short-chain fatty acids; ENS: enteric nervous system; and HPA axis: hypothalamic-pituitary-adrenal axis (Grodzicki et al., 2021).