title: Ultraviolet-vis degradation of iprodione and estimation of the acute toxicity of its photodegradation products.
abstract: The UV-vis photodegradation of iprodione in water was investigated with a high pressure mercury lamp photoreactor. Five photoproducts of iprodione were characterized by LC-HR-MS/MS and isotopic labeling; none of them has been reported in previous studies. Three of them result from the elimination of one or two chlorine atoms followed by hydroxy or hydrogen addition while the two others are cyclic isomers of iprodione. An ICR mass spectrometer was used for by-products identification; concentrations of photoproducts were estimated with a triple quadrupole instrument, using iprodione-D5 as an internal standard. Phototransformation mechanisms were postulated to rationalize photoproducts formation. In silico QSAR toxicity predictions were conducted with the Toxicity Estimation Software Tool (T.E.S.T.) considering oral rat LD50, mutagenicity and developmental toxicity. Low oral rat LD50 values of 350 mg/kg and 759 mg/kg were predicted for cyclic isomers of iprodione, compared to that of the parent molecule (2776 mg/kg). Toxicity estimations exhibited that all the iprodione photoproducts could be mutagenic while the parent compound is not. In vitro assays on Vibrio fischeri were achieved on both irradiated and non-irradiated aqueous solutions of iprodione and on HPLC fractions containing isolated photoproducts. Phenolic photoproducts were shown to be mainly responsible for toxicity enhancement with EC50 values of 0.3 and 0.5 ppm, for the bi- and mono-phenolic compounds issued from chlorine elimination.
authors.affiliation: Laboratoire de Chimie Moléculaire UMR-9168, École Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Lassalle
authors.affiliation: Laboratoire de Chimie Moléculaire UMR-9168, École Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Héla
authors.initials: H
authors.lastname: Jellouli
authors.affiliation: Laboratoire de Chimie Moléculaire UMR-9168, École Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Laurie
authors.initials: L
authors.lastname: Ballerini
authors.affiliation: Département de Génie Biologique, Université Libre de Tunis, Institut Polytechnique IP2 - 30, Av. Kheireddine Pacha, 1002 Tunis, Tunisia.
authors.forename: Yasmine
authors.initials: Y
authors.lastname: Souissi
authors.affiliation: Laboratoire de Chimie Moléculaire UMR-9168, École Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Édith
authors.initials: É
authors.lastname: Nicol
authors.affiliation: Laboratoire de Chimie Moléculaire UMR-9168, École Polytechnique, 91128 Palaiseau Cedex, France.
authors.forename: Sophie
authors.initials: S
authors.lastname: Bourcier
authors.affiliation: Laboratoire de Chimie Moléculaire UMR-9168, École Polytechnique, 91128 Palaiseau Cedex, France. Electronic address: stephane.bouchonnet@polytechnique.edu.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Bouchonnet
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D000620:Aminoimidazole Carboxamide / Q000031:analogs & derivatives* / Q000737:chemistry / Q000633:toxicity; D000818:Animals; D002851:Chromatography, High Pressure Liquid; D006827:Hydantoins / Q000737:chemistry* / Q000633:toxicity; D010782:Photolysis; D021281:Quantitative Structure-Activity Relationship; D051381:Rats; D053719:Tandem Mass Spectrometry; D014466:Ultraviolet Rays
chemical_list: D006827:Hydantoins; D000620:Aminoimidazole Carboxamide; C033148:iprodione
keywords: In silico tests; In vitro tests; Iprodione; Photolysis; Transformation products; Vibrio fischeri