Identification of a phytotoxic photo-transformation product of diclofenac using effect-directed analysis.
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.
Schulze
Tobias
T
UFZ Helmholtz-Centre for Environmental Research, Department of Effect-Directed Analysis, Permoserstrasse 15, 04318 Leipzig, Germany. tobias.schulze@ufz.de
Weiss
Sara
S
Schymanski
Emma
E
von der Ohe
Peter Carsten
PC
Schmitt-Jansen
Mechthild
M
Altenburger
Rolf
R
Streck
Georg
G
Brack
Werner
W
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
D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac