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Scrano, L.* ; Bufo, S.A.* ; D' Auria, M.* ; Méallier, P.* ; Behechti, A. ; Schramm, K.-W.

Photochemistry and Photoinduced Toxicity of Acifluorfen, a Diphenyl-Ether Herbicide.

J. Environ. Qual. 31, 268-274 (2002)
Open Access Green as soon as Postprint is submitted to ZB.
Photochemistry studies can be helpful in assessing the environmental fate of chemicals. Photochemical reactions lead to the formation of by-products that can exhibit different toxicological properties from the original compound. For this reason the photochemical behavior of the herbicide acifluorfen (5-[2-chloro-4-(trifluoromethyl)phenoxy]-2-nitrobenzoic acid) in the presence of different solvents was studied. Photochemical reactions were carried out using a high-pressure mercury are and a solar simulator. Kinetic parameters and quantum yields were determined. The identification of photoproducts was performed by mass spectrometry and [H-1] nuclear magnetic resonance (NMR). Nitrofluorfen, hydroxy-nitrofluorfen, 2-chphenol, 5-trifluoromethyl-5'-nitrodibenzofuran, and other derivatives were identified. The photochemical reactions were also carried out in the presence of either a singlet or a triplet quencher, and in the presence of either a radical initiator or a radical inhibitor. Substances, used as inhibitors of the excited levels T-1 and S-1. showed that photodegradation of acifluorfen begins from a singlet state S-1 through a pi,pi* transition. The role of free radicals in the photodegradation of acifluorfen was determined and a radical mechanism was proposed. Toxicity tests against Daphnia magna Strauss showed that acifluorfen was not toxic at a concentration of 0.1 mM; however, photoproducts formed after 36 h of UV exposure of the herbicide induced a remarkable toxicity to the test organism.
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Publication type Article: Journal article
Document type Scientific Article
Corresponding Author
Keywords AQUEOUS-SOLUTION; DAPHNIA-MAGNA; OXYFLUORFEN; LIGHT; ACID
ISSN (print) / ISBN 0047-2425
e-ISSN 1537-2537
Journal Journal of Environmental Quality
Quellenangaben Volume: 31, Issue: , Pages: 268-274 Article Number: , Supplement: ,
Publisher American Society of Agronomy
Non-patent literature Publications
Reviewing status Peer reviewed
Institute(s) Institute of Ecological Chemistry (IOEC)