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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Photodegradation of sulfamethoxazole in various aqueous media: Persistence, toxicity and photoproducts assessment

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Author(s):
Trovo, Alam G. [1] ; Nogueira, Raquel F. P. [1] ; Agueera, Ana [2] ; Sirtori, Carla [2, 3] ; Fernandez-Alba, Amadeo R. [2]
Total Authors: 5
Affiliation:
[1] Sao Paulo State Univ, UNESP, Inst Chem Araraquara, Dept Analyt Chem, BR-14801970 Araraquara, SP - Brazil
[2] Univ Almeria, Pesticide Residues Grp, Almeria 04120 - Spain
[3] Minist Educ Brazil, Capes Fdn, BR-70359970 Brasilia, DF - Brazil
Total Affiliations: 3
Document type: Journal article
Source: Chemosphere; v. 77, n. 10, p. 1292-1298, NOV 2009.
Web of Science Citations: 161
Abstract

The photochemical transformation of sulfa methoxazole (SMX) was investigated in different water matrices: distilled water (DW), distilled water + nitrate (10 and 20 mg L(-1)) and seawater (SW) to evaluate its persistence, toxicity and degradation pathway. A solar simulator Suntest CPS+ was used for the irradiation experiments. Identification of transformation products was performed in DW by liquid chromatography-time of flight-mass spectrometry (LC-TOF-MS). Acute toxicity of irradiated solutions was monitored by Vibrio fischeri and Daphnia magna bioassays in DW. Differences in the degradation rates were observed between DW and SW, being slower in SW. Presence of nitrate (indirect photolysis) in distilled water did not affect SMX degradation rate. No dissolved organic carbon (DOC) removal was observed in any case, thus indicating the formation of abundant transformation products (TPs). Analysis by LC-TOF-MS allowed the identification of up to nine transformation products during photolysis in DW. Only three of them had been previously reported in the literature, detected with other techniques. The cleavage of the sulfonamide bond and the photoisomerization by rearrangement of the isoxazole ring represent the main pathways, at the time that generate the most abundant and persistent intermediates. The acute toxicity of SMX solution varied according to test organisms. Daphnia magna was the most sensitive showing an increase from 60% to 100% immobilization after 30 h of irradiation when depletion of SMX was achieved, thus indicating the higher toxicity of the phototransformation products generated. (C) 2009 Elsevier Ltd. All rights reserved. (AU)