Effects of weathering on the properties and fate of secondary microplastics from a polystyrene single-use cup

Olubukola S Alimi; Dominique Claveau-Mallet; Mathieu Lapointe; Thinh Biu; Lan Liu; Laura M Hernandez; Stéphane Bayen; Nathalie Tufenkji

doi:10.1016/j.jhazmat.2023.131855

Effects of weathering on the properties and fate of secondary microplastics from a polystyrene single-use cup

J Hazard Mater. 2023 Oct 5:459:131855. doi: 10.1016/j.jhazmat.2023.131855. Epub 2023 Jun 14.

Authors

Olubukola S Alimi¹, Dominique Claveau-Mallet², Mathieu Lapointe³, Thinh Biu⁴, Lan Liu⁵, Laura M Hernandez⁴, Stéphane Bayen⁵, Nathalie Tufenkji⁴

Affiliations

¹ Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5 Canada; Department of Civil and Environmental Engineering, University of Alberta, Edmonton, T6G 1H9 Canada. Electronic address: oalimi@ualberta.ca.
² Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5 Canada; Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, 2900 Edouard-Montpetit, Montreal, Canada.
³ Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5 Canada; Department of Construction Engineering, École de technologie supérieure - University of Québec, Montreal, Quebec, H3C 1K3, Canada.
⁴ Department of Chemical Engineering, McGill University, Montreal, Quebec, H3A 0C5 Canada.
⁵ Department of Food Science and Agricultural Chemistry, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, Montreal, Canada.

PMID: 37478596
DOI: 10.1016/j.jhazmat.2023.131855

Abstract

In this work, we probed the changes to some physicochemical properties of polystyrene microplastics generated from a disposable cup as a result of UV-weathering, using a range of spectroscopy, microscopy, and profilometry techniques. Thereafter, we aimed to understand how these physicochemical changes affect the microplastic transport potential and contaminant sorption ability in model freshwaters. Exposure to UV led to measured changes in microplastic hydrophobicity (20-23 % decrease), density (3% increase), carbonyl index (up to 746 % increase), and microscale roughness (24-86 % increase). The settling velocity of the microplastics increased by 53 % after weathering which suggests that UV aging can increase microplastic deposition to sediments. This impact of aging was greater than the effect of the water temperature. Weathered microplastics exhibited reduced sorption capacity (up to 52 % decrease) to a model hydrophobic contaminant (triclosan) compared to unaged ones. The adsorption of triclosan to both microplastics was slightly reversible with notable desorption hysteresis. These combined effects of weathering could potentially increase the transport potential while decreasing the contaminant transport abilities of microplastics. This work provides new insights on the sorption capacity and mobility of a secondary microplastic, advances our knowledge about their risks in aquatic environments, and the need to use environmentally relevant microplastics.

Keywords: Contaminant mobility; Food and beverage container; Organic pollutant; Plastic degradation; Plastic pollution; Vertical transport.