title: Identification of a phytotoxic photo-transformation product of diclofenac using effect-directed analysis.
abstract: The pharmaceutical diclofenac (DCF) is released in considerably high amounts to the aquatic environment. Photo-transformation of DCF was reported as the main degradation pathway in surface waters and was found to produce metabolites with enhanced toxicity to the green algae Scenedesmus vacuolatus. We identified and subsequently confirmed 2-[2-(chlorophenyl)amino]benzaldehyde (CPAB) as a transformation product with enhanced toxicity using effect-directed analysis. The EC(50) of CPAB (4.8 mg/L) was a factor of 10 lower than that for DCF (48.1 mg/L), due to the higher hydrophobicity of CPAB (log K(ow) = 3.62) compared with DCF (log D(ow) = 2.04) at pH 7.0.
authors.affiliation: UFZ Helmholtz-Centre for Environmental Research, Department of Effect-Directed Analysis, Permoserstrasse 15, 04318 Leipzig, Germany. tobias.schulze@ufz.de
authors.forename: Tobias
authors.initials: T
authors.lastname: Schulze
authors.forename: Sara
authors.initials: S
authors.lastname: Weiss
authors.forename: Emma
authors.initials: E
authors.lastname: Schymanski
authors.forename: Peter Carsten
authors.initials: PC
authors.lastname: von der Ohe
authors.forename: Mechthild
authors.initials: M
authors.lastname: Schmitt-Jansen
authors.forename: Rolf
authors.initials: R
authors.lastname: Altenburger
authors.forename: Georg
authors.initials: G
authors.lastname: Streck
authors.forename: Werner
authors.initials: W
authors.lastname: Brack
mesh_terms: D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000737:chemistry / Q000633:toxicity; D000460:Chlorophyta / Q000187:drug effects*; D004008:Diclofenac / Q000737:chemistry* / Q000633:toxicity*; D057927:Hydrophobic and Hydrophilic Interactions; D010782:Photolysis; D013472:Sunlight
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac