Toward Understanding the Environmental Risks of Combined Microplastics/Nanomaterials Exposures: Unveiling ZnO Transformations after Adsorption onto Polystyrene Microplastics in Environmental Solutions

• Published in: Global challenges Vol. 7; no. 8; pp. 2300036 - n/a
• Main Authors: Gomez‐Gonzalez, Miguel A., Da Silva‐Ferreira, Tatiana, Clark, Nathaniel, Clough, Robert, Quinn, Paul D., Parker, Julia E.
• Format: Journal Article
• Language: English
• Published: Germany John Wiley & Sons, Inc 01-08-2023; John Wiley and Sons Inc; Wiley
• Subjects: Adsorption; Aging; Chemical analysis; Drinking water; Environmental release; Environmental risk; Microplastics; microplastics (MPs); Microspheres; Nanomaterials; Nanoparticles; Nanotechnology; Organic chemicals; Piezoelectricity; Plastic debris; Plastic pollution; Pollutants; Polymers; Polystyrene; Polystyrene resins; Radiation; Scanning electron microscopy; Seawater; Spectroscopy; Structure-function relationships; Sun screens; Sunscreen; Surface chemistry; Toxicity; Transformations; Water analysis; X ray absorption; X‐ray absorption near‐edge structure (XANES) spectroscopy; X‐ray fluorescence (XRF) nano‐imaging; Zinc oxide; Zinc oxides; Zn speciation changes; ZnO nanomaterials; Zn speciation changes; microplastics (MPs); X‐ray absorption near‐edge structure (XANES) spectroscopy; X‐ray fluorescence (XRF) nano‐imaging; ZnO nanomaterials
• ISSN: 2056-6646; 2056-6646
• DOI: 10.1002/gch2.202300036

Over recent decades, there has been a dramatic increase in the manufacture of engineered nanomaterials, which has inevitably led to their environmental release. Zinc oxide (ZnO) is among the more abundant nanomaterial manufactured due to its advantageous properties, used for piezoelectric, semiconducting, and antibacterial purposes. Plastic waste is ubiquitous and may break down or delaminate into smaller microplastics, leaving open the question of whether these small polymers may alter the fate of ZnO through adsorption within aquatic media (tap‐water and seawater). Here, scanning electron microscopy analysis confirms the effective Zn nano/microstructures adsorption onto polystyrene surfaces after only 24‐h incubation in the aquatic media. After pre‐aging the nanomaterials for 7‐days in different environmental media, nanoprobe X‐ray absorption near‐edge spectroscopy analysis reveals significant ZnO transformation toward Zn‐sulfide and Zn‐phosphate. The interaction between a commercial ZnO‐based sunscreen with polystyrene and a cleanser consumer containing microbeads with ZnO nanomaterials is also studied, revealing the adsorption of transformed Zn‐species in the microplastics surfaces, highlighting the environmental relevancy of this work. Understanding the structural and functional impacts of the microplastics/ZnO complexes, and how they evolve, will provide insights into their chemical nature, stability, transformations, and fate, which is key to predicting their bioreactivity in the environment.
The ability of polystyrene microplastics to sorb aged ZnO nanomaterials in relevant freshwater and seawater scenarios is investigated for the first time, including potential ZnO leaching from commercial sunscreens. The adsorbed nanomaterials are examined by X‐ray nano‐spectromicroscopy, revealing significant ZnO transformation toward Zn‐sulfide and Zn‐phosphate. These results are crucial for determining their fate and behaviour in the environment after disposal.