Heteroaggregates of Polystyrene Nanospheres and Organic Matter: Preparation, Characterization and Evaluation of Their Toxicity to Algae in Environmentally Relevant Conditions

Abstract

The environmental fate and behavior of nanoplastics (NPs) and their toxicity against aquatic organisms are under current investigation. In this work, relevant physicochemical characterizations were provided to analyze the ecotoxicological risk of NPs in the aquatic compartment. For this purpose, heteroaggregates of 50 nm polystyrene nanospheres and natural organic matter were prepared and characterized. The kinetic of aggregation was assimilated to a reaction-limited colloid aggregation mode and led to the formation of heteroaggregates in the range of 100–500 nm. Toxicities of these heteroaggregates and polystyrene nanospheres (50 and 350 nm) were assessed for a large range of concentrations using four benthic and one planktonic algal species, in regards to particle states in the media. Heteroaggregates and nanospheres were shown to be stable in the exposure media during the ecotoxity tests. The algal species exhibited very low sensitivity (growth and photosynthetic activity), with the noteworthy exception of the planktonic alga, whose growth increased by more than 150% with the heteroaggregates at 1 µg L−1. Despite the lack of a strong direct effect of the NPs, they may still impair the functioning of aquatic ecosystems by destabilizing the competitive interactions between species. Moreover, further work should assess the toxicity of NPs associated with other substances (adsorbed pollutants or additives) that could enhance the NP effects.

Chemical Analysis of Microplastics and Nanoplastics: Challenges, Advanced Methods, and Perspectives

“…Besides SEM, transmission electron microscopy (TEM) has also been applied for the characterization of microplastics and nanoplastics in soil samples. ,, For example, Watteau et al applied TEM/EDX together with Py-GC/MS for the MP detection in soil amended with municipal solid waste composts . For the TEM/EDX measurements subsamples for different size fractions were fixed in osmium tetroxide, dehydrated, embedded in epoxy resin and cut in ultrathin sections using ultramicrotome.…”

Ecotoxicity of Heteroaggregates of Polystyrene Nanospheres in Chironomidae and Amphibian

“…Materials, heteroaggregates preparation, and fundamental characterizations/methods were described in detail in Rowenczyk et al [ 32 ]. Table 1 summarizes the characteristics of the particles in water.…”

“…Interaction can affect their mobility, stability, and distribution in a water column [ 30 ]. Components of Organic Matter (OM) may be rapidly absorbed by particles in layers, forming their heteroaggregation and controlling their final fate, reactivity, and finally impact organisms [ 31 , 32 ].…”

“…A previous study evaluated the toxicity of the exact same particles towards freshwater algae (four benthic and one planktonic algal species) in regard to particle states in the media [ 32 ]. Despite the very low toxicity exhibited by the algal species, the functioning of aquatic ecosystems may be destabilized because of the competitive interactions between species.…”

The role of microplastics in microalgae cells aggregation: A study at the molecular scale using atomic force microscopy

“…Then, MPs were also found to have a number of adverse effects on microalgae, including inhibition of growth (Sjollema et al, 2016;Zhang et al, 2017;Liu et al, 2020;Song et al, 2020), decrease in chlorophyll content (Tunali et al, 2020;Wu et al, 2019) and photosynthetic activity (Zhang et al, 2017), physical and morphological damages (Mao et al, 2018), oxydative stress (Xiao et al, 2020). Finally, due to constant movement in the aquatic environment, plastic is a potential vector of geographic transport for the migration of microalgae (Rowenczyk et al, 2021). This phenomenon creates a risk of introducing pathogenic species (e.g.…”