title: UV photolysis of diclofenac in water; kinetics, degradation pathway and environmental aspects.
abstract: In this study, the photolysis behavior of commonly used anti-inflammatory drug diclofenac (DCF) was investigated using UV-C and UV-A irradiation. In that purpose, DCF conversion kinetics, mineralization of organic content, biodegradability, and toxicity were monitored and compared. The results showed different kinetics of DCF conversion regarding the type of UV source applied. However, in both cases, the mineralization extent reached upon complete DCF conversion is rather low (≤10 %), suggesting that the majority of DCF was transformed into by-products. Formation/degradation of main degradation by-products was monitored using high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI-MS/MS), whereas different profiles were obtained by UV-C and UV-A photolysis. The results of bioassays revealed that biodegradability of DCF solutions remained low through the applied treatments. The toxicity of irradiated DCF solutions was evaluated using Vibrio fischeri. A significant reduction of toxicity, especially in the case of UV-A radiation, was observed upon complete degradation of DCF. In addition to toxicity reduction, calculated Log K OW values of DCF degradation by-products indicate their low potential for bioaccumulation (Log K OW ≤ 3) in comparison to the parent substance.
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, Zagreb, 10000, Croatia.
authors.forename: Marin
authors.initials: M
authors.lastname: Kovacic
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, Zagreb, 10000, Croatia.
authors.forename: Daria
authors.initials: D
authors.lastname: Juretic Perisic
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, Zagreb, 10000, Croatia.
authors.forename: Martina
authors.initials: M
authors.lastname: Biosic
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, Zagreb, 10000, Croatia.
authors.forename: Hrvoje
authors.initials: H
authors.lastname: Kusic
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, Zagreb, 10000, Croatia. sbabic@fkit.hr.
authors.forename: Sandra
authors.initials: S
authors.lastname: Babic
authors.affiliation: Faculty of Chemical Engineering and Technology, University of Zagreb, Marulicev trg 19, Zagreb, 10000, Croatia. abozic@fkit.hr.
authors.forename: Ana
authors.initials: A
authors.lastname: Loncaric Bozic
mesh_terms: D048908:Aliivibrio fischeri / Q000187:drug effects; D001673:Biodegradation, Environmental; D004008:Diclofenac / Q000032:analysis / Q000528:radiation effects / Q000633:toxicity; D010782:Photolysis; D014466:Ultraviolet Rays; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000528:radiation effects / Q000633:toxicity
chemical_list: D014874:Water Pollutants, Chemical; D004008:Diclofenac
keywords: Biodegradability; Degradation pathway; Diclofenac; Toxicity; UV photolysis