Characterization of microplastic-derived dissolved organic matter in freshwater: Effects of light irradiation and polymer types

Document Type

Article

Publication Date

3-1-2024

Abstract

This study investigated the impacts of light irradiation and polymer types on the leaching behavior of dissolved organic matter (DOM) from microplastics (MPs) in freshwater. Polypropylene had the highest leaching capacity of DOM after photoaging, followed by polystyrene (PS), polyamide (PA) and polyethylene terephthalate (PET). While similarly low levels of DOM were observed in the remaining 5 MP suspensions under UV irradiation and in almost all MP suspensions (except PA) under darkness. These suggest that the photooxidation of some buoyant plastics may influence the carbon cycling of nature waters. Among 9 MP-derived leachates, PET leachates had the highest chromophoric DOM concentration and aromaticity, probably owing to the special benzene rings and carbonyl groups in PET structures and its fast degradation rate. Protein-like substances were the primary fluorescent DOM in MP suspensions (except PS), especially in darkness no other fluorescent substances were found. Considering the bio-labile properties of proteins together, MPs regardless of floating or suspended in an aquatic environment may have prevalent long-term effects on microbial activities. Besides, from monomers to hexamers with newly formed chemical bonds were identified in UV-irradiated MP suspensions. These results will contribute to a deep insight into the potential ecological effects related to MP degradation.

Identifier

85187216325 (Scopus)

Publication Title

Environment International

External Full Text Location

https://doi.org/10.1016/j.envint.2024.108536

e-ISSN

18736750

ISSN

01604120

PubMed ID

38471263

Volume

185

Grant

310432106

Fund Ref

Beijing Normal University

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