Aggregation kinetics and stability of biodegradable nanoplastics in aquatic environments: Effects of UV-weathering and proteins.

Autor: Yu Y; Department of Crop & Soil Sciences, Washington State University, Puyallup and Pullman, WA, USA., Astner AF; Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, TN, USA., Zahid TM; Department of Civil and Environmental Engineering, Washington State University, Pullman, WA, USA., Chowdhury I; Department of Civil and Environmental Engineering, Washington State University, Pullman, WA, USA., Hayes DG; Department of Biosystems Engineering and Soil Science, The University of Tennessee, Knoxville, TN, USA., Flury M; Department of Crop & Soil Sciences, Washington State University, Puyallup and Pullman, WA, USA. Electronic address: flury@wsu.edu.
Jazyk: angličtina
Zdroj: Water research [Water Res] 2023 Jul 01; Vol. 239, pp. 120018. Date of Electronic Publication: 2023 May 02.
DOI: 10.1016/j.watres.2023.120018
Abstrakt: Plastic pollution caused by conventional plastics has promoted the development and use of biodegradable plastics. However, biodegradable plastics do not degrade readily in water; instead, they can generate micro- and nanoplastics. Compared to microplastics, nanoplastics are more likely to cause negative impacts to the aquatic environment due to their smaller size. The impacts of biodegradable nanoplastics highly depend on their aggregation behavior and colloidal stability, which still remain unknown. Here, we studied the aggregation kinetics of biodegradable nanoplastics made of polybutylene adipate co-terephthalate (PBAT) in NaCl and CaCl 2 solutions as well as in natural waters before and after weathering. We further studied the effect of proteins on aggregation kinetics with both negative-charged bovine serum albumin (BSA) and positive-charged lysozyme (LSZ). For pristine PBAT nanoplastics (before weathering), Ca 2＋ destabilized nanoplastic suspensions more aggressively than Na + , with the critical coagulation concentration being 20 mM in CaCl 2 vs 325 mM in NaCl. Both BSA and LSZ promoted the aggregation of pristine PBAT nanoplastics, and LSZ showed a more pronounced effect. However, no aggregation was observed for weathered PBAT nanoplastics under most experimental conditions. Further stability tests demonstrated that pristine PBAT nanoplastics aggregated substantially in seawater, but not in freshwater, and only slightly in soil pore water; while weathered PBAT nanoplastics remained stable in all natural waters. These results suggest that biodegradable nanoplastics, especially weathered biodegradable nanoplastics, are highly stable in the aquatic environment, even in the marine environment.
Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2023 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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