Fate of Fluometuron Dissolved in Natural Waters and Exposed to Solar Light

Abstract

To predict the fate of pollutants in the aquatic environment and to assess the risk they may pose, it is necessary to improve our knowledge on their chemical reactions under environmental conditions. Photochemical reactions are a route for the attenuation of organic pollutants present in surface waters. This work was devoted to herbicide fluometuron which is used to control weeds in cotton. Phototransformation of fluometuron (1 µM) in natural sunlight was investigated in synthetic waters containing either natural organic matter, nitrate ions or both in order to mimic reactions taking place in aquatic environments. Fluometuron underwent photolysis and its degradation was faster in the presence of fulvic acids (10 mg l-1, factor 2.5) or nitrates (25 mg l-1, factor 15) than in Milli-Q water showing the importance of natural waters constituents. Identification of major photoproducts was conducted under laboratory conditions. Hydroxylation of the aromatic ring with or without hydrolysis of CF into CO2H and oxidation of the urea chain leading to demethylation were observed

Keywords

• photodegradation, phenylureas herbicides, solar light, naturel waters

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