Photochemical transformation of zearalenone in aqueous solutions under simulated solar irradiation: Kinetics and influence of water constituents.

Autor: Emídio ES; Analytical Chemistry Department, Chemistry Institute, São Paulo State University-UNESP, Araraquara, SP, 14801-970, Brazil., Calisto V; Department of Chemistry and CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal. Electronic address: vania.calisto@ua.pt., de Marchi MR; Analytical Chemistry Department, Chemistry Institute, São Paulo State University-UNESP, Araraquara, SP, 14801-970, Brazil., Esteves VI; Department of Chemistry and CESAM (Centre for Environmental and Marine Studies), University of Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal. Electronic address: valdemar@ua.pt.
Jazyk: angličtina
Zdroj: Chemosphere [Chemosphere] 2017 Feb; Vol. 169, pp. 146-154. Date of Electronic Publication: 2016 Nov 18.
DOI: 10.1016/j.chemosphere.2016.11.042
Abstrakt: The presence of estrogenic mycotoxins, such as zearalenone (ZEN), in surface waters is an emerging environmental issue. Little is known about its phototransformation behavior, which may influence its environmental fate. In this context, the phototransformation of ZEN was investigated in pure water, river water and estuarine water using simulated sunlight irradiation. Kinetic studies revealed that two concomitant processes contribute to the fate of ZEN under solar irradiation: photoisomerization and photodegradation. This phototransformation followed a pseudo-first order kinetics. ZEN degrades quickly in natural waters and slowly in deionized water, with half-lives (t 1/2 ) of 28 ± 4 min (estuarine water), 136 ± 21 min (river water) and 1777 ± 412 min (deionized water). The effects of different water constituents on the phototransformation of ZEN in aqueous solution have been assessed (NaCl, Ca 2+ , Mg 2+ , Fe 3+ , NO 3 - and oxalate ions, synthetic seawater, Fe(III)-oxalate and Mg(II)-oxalate complexes, humic acids, fulvic acids and XAD-4 fraction). In the presence of synthetic seawater salt (t 1/2  = 18 ± 5 min) and Fe(III)-oxalate complexes (t 1/2  = 61 ± 9 min), the transformation rate increased considerably in relation to other water constituents tested. The solution pH also had a considerable effect in the kinetics with maximum transformation rates occurring around pH 8.5. These results allow us to conclude that phototransformation by solar radiation can be an important degradation pathway of ZEN in natural waters.
(Copyright © 2016 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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