Heterogeneous oxidation of two triazole pesticides (diniconazole and tebuconazole) by OH-radicals and ozone

O Rokbani; S Fattouch; A Chakir; E Roth

doi:10.1016/j.scitotenv.2019.133745

Heterogeneous oxidation of two triazole pesticides (diniconazole and tebuconazole) by OH-radicals and ozone

Sci Total Environ. 2019 Dec 1:694:133745. doi: 10.1016/j.scitotenv.2019.133745. Epub 2019 Aug 2.

Authors

O Rokbani¹, S Fattouch², A Chakir³, E Roth⁴

Affiliations

¹ Université de Reims Champagne Ardenne, CNRS, GSMA, UMR 7331, 51097 Reims, France GSMA, UMR CNRS 7331, Moulin de la Housse, B.P. 1039, 51687 Reims, France; Food and Molecular Biochemistry Laboratory, National Institute of Applied Sciences Technology (INSAT), University of Carthage, Tunis 1080, Tunisia; Faculty of Sciences of Bizerte, University of Carthage, Tunis 1080, Tunisia.
² Food and Molecular Biochemistry Laboratory, National Institute of Applied Sciences Technology (INSAT), University of Carthage, Tunis 1080, Tunisia.
³ Université de Reims Champagne Ardenne, CNRS, GSMA, UMR 7331, 51097 Reims, France GSMA, UMR CNRS 7331, Moulin de la Housse, B.P. 1039, 51687 Reims, France.
⁴ Université de Reims Champagne Ardenne, CNRS, GSMA, UMR 7331, 51097 Reims, France GSMA, UMR CNRS 7331, Moulin de la Housse, B.P. 1039, 51687 Reims, France. Electronic address: estelle.roth@univ-reims.fr.

PMID: 31756792
DOI: 10.1016/j.scitotenv.2019.133745

Abstract

Tebuconazole (Tbz) and diniconazole (Dnz) were deposited as thin film on quartz plaques. They were submitted to OH-radicals and ozone and their kinetic was measured. OH-radical oxidation was performed relative to a reference whose rate constant is well known. Terbuthylazine (Tbt) and Chlorpyriphos Ethyl (Clp) were chosen as reference for Tbz and Dnz kinetics determination, respectively. OH-radical rate constants of Tbz and Dnz were found to be: k_OH+Tbz = (1.7 ± 0.2) 10^-13 cm³ molecule^-1 s^-1 and k _OH+Dnz = (1.74 ± 1.21) 10^-12 cm³ molecule^-1 s^-1, respectively. Ozone heterogeneous oxidation rate constants were determined in an absolute way: k_O3+Tbz = (0.5 ± 0.2) 10^-20 cm³ molecule^-1 s^-1; k_O3+Dnz = (1.4 ± 0.2) 10^-19 cm³ molecule^-1 s^-1. Dnz is ten times more reactive toward OH-radicals than Tbz and 27 times more reactive than Tbz toward ozone maybe because of the presence of a double bond in Dnz. Lifetimes of Tbz and Dnz on quartz like surfaces are against OH-radicals are of 68 days and 8 days, respectively and 4 months and several years against ozone, respectively.

Keywords: Diniconazole; Heterogeneous reaction; OH-radicals; Ozone; Pesticide; Tebuconazole.