New publication of COSM team : “Surface functionalization determines behavior of nanoplastic solutions in model aquatic environments”
Kevin Tallec, Océane Blard, Carmen González-Fernández, Guillaume Brotons, Mathieu Berchel, Philippe Soudant, Arnaud Huvet, Ika Paul-Pont
Chemosphere, 2019, 225, 639-646. 10.1016/j.chemosphere.2019.03.077
Plastic debris are classified as a function of their size and recently a new class was proposed, the nanoplastics. Nano-sized plastics have a much greater surface area to volume ratio than larger particles, which increases their reactivity in aquatic environment, making them potentially more toxic. Only little information is available about their behavior whereas it crucially influences their toxicity. Here, we used dynamic light scattering (DLS) to explore the influence of environmental factors (fresh- and saltwater, dissolved organic matter) on the behavior (surface charge and aggregation state) of three different nano-polystyrene beads with (i) no surface functionalization (plain), (ii) a carboxylic or (iii) an amine functionalization. Overall, the positive amine particles were very mildly affected by changes in environmental factors with no effect of the salinity gradient. These observations are supposedly linked to a coating specificity leading to repulsive mechanisms. In contrast, the stability of the negatively charged carboxylic and plain nanobeads was lost under an increasing ionic strength, resulting in homo-aggregation (up to 10 μm). The increase in organic matter content had negligible effect on these two nanobeads.