Aqueous degradation of tioxazafen: Kinetics, products, pathways, and toxicity.

Autor: Lu Z; College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China., Zhang F; College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China., Yang Y; College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China., Zhang H; College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China., Liu J; Jilin Agro-Tech Extension Station, Changchun, Jilin 130022, China., Hou Z; College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China., Zhao D; Center of Quality Standard and Testing Technology for Agro-Products, Jilin Agricultural University, Changchun, Jilin 130118, China., Meng X; Center of Quality Standard and Testing Technology for Agro-Products, Jilin Agricultural University, Changchun, Jilin 130118, China., Ren W; Center of Quality Standard and Testing Technology for Agro-Products, Jilin Agricultural University, Changchun, Jilin 130118, China., Lu Z; College of Plant Protection, Jilin Agricultural University, Changchun, Jilin 130118, China. Electronic address: luzhongbin100@jlau.edu.cn.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 Oct 01; Vol. 945, pp. 173817. Date of Electronic Publication: 2024 Jun 14.
DOI: 10.1016/j.scitotenv.2024.173817
Abstrakt: Tioxazafen (TXF) is the first 1,2,4-oxadiazole nematicide. In the present study, the aqueous degradation of TXF was investigated in terms of hydrolysis and photolysis. Under the irradiation of simulated sunlight, TXF degraded very fast in ultrapure water and buffers with half-lives (t 1/2 s) <8.3 min. A sole photoproduct (PP) PP228a was isolated, and identified by spectroscopic means (UV, IR, HRMS, and 1 H NMR) to be the thiophen-3-yl isomer converted from its thiophen-2-yl parent. Comparing with TXF, PP228a had quite extended t 1/2 s ranging from 6.9 to 7.9 d. The photolysis kinetics of TXF and PP228a showed no pH-dependence, and varied for each individual compound as affected by nitrate, fulvic acid, and humic acid. Besides, both compounds were hydrolytically stable. 6 PPs of PP228a were identified, with two of them being its isomers. The mechanisms involved in the process included the biradical photosensitization, photoinduced electron transfer, and ring contraction-ring expansion reactions. The 48 h-EC 50 to Daphnia magna was 0.808 mg/L for PP228a comparing to >1.12 mg/L for TXF, while the results of Vibrio fischeri assays indicated that one or more PPs of PP228a might have higher toxicity.
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 © 2024 Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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