Polyamide microplastics in wastewater as vectors of cationic pharmaceutical drugs.

Wagstaff, Antony; Lawton, Linda A.; Petrie, Bruce

Abstract

Reported here is the first study to investigate the adsorption of pharmaceutical drugs to microplastics in wastewater. Wastewater is an environmental source of microplastics and pharmaceuticals, which is discharged as treated effluent or combined sewer overflows. In this study, adsorption of cationic pharmaceuticals, with a range of octanol-water distribution coefficients, to polyamide (Nylon 12) microplastics was investigated in real wastewater samples. Significant adsorption was observed for the more hydrophobic pharmaceuticals studied, propranolol, amitriptyline, and fluoxetine, with equilibrium reached within 24 h. Microplastic-wastewater distribution coefficients for these three pharmaceuticals were 191, 749 and 1020 L kg−1, respectively. Favourable wastewater conditions for adsorption of pharmaceuticals to polyamide were at pH>7, summer temperatures (20°C), and no stormwater dilution. Adsorption of the more hydrophilic pharmaceuticals atenolol, pseudoephedrine, metoprolol, and tramadol was ≤7% under all conditions and considered insignificant. Limited desorption (7–17%) of propranolol, amitriptyline, and fluoxetine was observed in river water over 24h. This suggests that microplastics may be able to transport adsorbed pharmaceuticals for considerable distances after discharge. In simulated gastric fluids their desorption increased to 24–27% and 40–58% in cold- and warm-blooded temperatures respectively. The findings demonstrate that wastewater microplastics could act as a vector of pharmaceutical drugs, from wastewater treatment plants to aquatic organisms. However, further research is needed to better appreciate the risks posed by pharmaceuticals adsorbed to microplastics in comparison to other organic particulates found in wastewater.

Citation

WAGSTAFF, A., LAWTON, L.A. and PETRIE, B. 2022. Polyamide microplastics in wastewater as vectors of cationic pharmaceutical drugs. Chemosphere [online], 288(Part 2), article 132578. Available from: https://doi.org/10.1016/j.chemosphere.2021.132578

• Journal Article Type: Article
• Acceptance Date: Oct 13, 2021
• Online Publication Date: Oct 14, 2021
• Publication Date: Feb 28, 2022
• Deposit Date: Oct 18, 2021
• Publicly Available Date: Oct 15, 2022
• Journal: Chemosphere
• Print ISSN: 0045-6535
• Electronic ISSN: 1879-1298
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 288
• Issue: Part 2
• Article Number: 132578
• DOI: https://doi.org/10.1016/j.chemosphere.2021.132578
• Keywords: Emerging contaminant; Adsorption; Desorption; Environmental chemistry; Water pollution; Microplastic
• Public URL: https://rgu-repository.worktribe.com/output/1490112
• Related Public URLs: https://rgu-repository.worktribe.com/output/1498657