title: Photochemical transformation of anionic 2-nitro-4-chlorophenol in surface waters: laboratory and model assessment of the degradation kinetics, and comparison with field data.
abstract: Anionic 2-nitro-4-chlorophenol (NCP) may occur in surface waters as a nitroderivative of 4-chlorophenol, which is a transformation intermediate of the herbicide dichlorprop. Here we show that NCP would undergo efficient photochemical transformation in environmental waters, mainly by direct photolysis and reaction with OH. NCP has a polychromatic photolysis quantum yield Φ(NCP)=(1.27±0.22)·10(-5), a rate constant with OH k(NCP,)(OH)=(1.09±0.09)·10(10) M(-1) s(-1), a rate constant with (1)O(2)k(NCP,1O2)=(2.15±0.38)·10(7) M(-1) s(-1), a rate constant with the triplet state of anthraquinone-2-sulphonate k(NCP,3AQ2S*)=(5.90±0.43)·10(8) M(-1) s(-1), and is poorly reactive toward CO(3)(-). The k(NCP,3AQ2S*) value is representative of reaction with the triplet states of chromophoric dissolved organic matter. The inclusion of photochemical reactivity data into a model of surface-water photochemistry allowed the NCP transformation kinetics to be predicted as a function of water chemical composition and column depth. Very good agreement between model predictions and field data was obtained for the shallow lagoons of the Rhône delta (Southern France).
authors.affiliation: Dipartimento di Chimica, Università di Torino, Via P. Giuria 5, 10125 Torino, Italy.
authors.forename: Babita
authors.initials: B
authors.lastname: Sur
authors.forename: Elisa
authors.initials: E
authors.lastname: De Laurentiis
authors.forename: Marco
authors.initials: M
authors.lastname: Minella
authors.forename: Valter
authors.initials: V
authors.lastname: Maurino
authors.forename: Claudio
authors.initials: C
authors.lastname: Minero
authors.forename: Davide
authors.initials: D
authors.lastname: Vione
mesh_terms: D004784:Environmental Monitoring; D006540:Herbicides / Q000032:analysis / Q000737:chemistry*; D007700:Kinetics; D008956:Models, Chemical; D009596:Nitrophenols / Q000032:analysis* / Q000737:chemistry; D055668:Photochemical Processes; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D006540:Herbicides; D009596:Nitrophenols; D014874:Water Pollutants, Chemical; C068311:4-chloro-2-nitrophenol