title: Role of oxygen and DOM in sunlight induced photodegradation of organophosphorous flame retardants in river water.
abstract: The wide use of organophosphorous flame retardants (OPFR) and plasticizers causes a continuous release of large quantities into natural waters. One of the main contributors to micropollutants depletion in surface water is sunlight induced phototransformations. This study aims to elucidate whether alkyl, chloroalkyl and aryl organophosphorus flame retardants undergo phototransformations in river water. To perform the experiments, nine OPFR were subjected to natural sunlight, Xe lamp (simulated sunlight) and UV-C irradiations in ultra-pure Milli-Q water, Milli-Q water with humic acid and river water. Experiments demonstrated that OPFR achieve an important degree of photodegradation noticeable at long irradiation time, although direct photolysis did not account as the main photodegration mechanism. Results indicated that sunlight absorbing OPFR exhibited photosensitizing activity. The presence of azide in ultra- pure water inhibited some OPFR photodegration by singlet oxygen (1O2) scavenging, and the absence of dissolved oxygen significantly depleted most of OPFR removal. In the conditions studied, humic acid inhibited OPFR phototransformations, while river water enhanced their removal. Results from this study point out the need to further investigate the role of some OPFR as photosensitizers, which are important for fate and ecological risk assessment of flame retardants and other micropollutants in water.
authors.affiliation: Department of Environmental Chemistry, IDAEA, CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: Joyce
authors.initials: J
authors.lastname: Cristale
authors.affiliation: Department of Chemical Engineering, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
authors.forename: Renato F
authors.initials: RF
authors.lastname: Dantas
authors.affiliation: Department of Chemical Engineering, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
authors.forename: Antonella
authors.initials: A
authors.lastname: De Luca
authors.affiliation: Department of Chemical Engineering, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain. Electronic address: carmesans@ub.edu.
authors.forename: Carmen
authors.initials: C
authors.lastname: Sans
authors.affiliation: Department of Chemical Engineering, University of Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain.
authors.forename: Santiago
authors.initials: S
authors.lastname: Esplugas
authors.affiliation: Department of Environmental Chemistry, IDAEA, CSIC, Jordi Girona 18-26, 08034 Barcelona, Spain.
authors.forename: Silvia
authors.initials: S
authors.lastname: Lacorte
keywords: Organophosphate esters; Photolysis; Photosensitizers; ROS; Singlet oxygen