Reductive transformation of carbamazepine by abiotic and biotic processes.
The antiepileptic drug carbamazepine (CBZ) is ubiquitously present in the anthropogenic water cycle and is therefore of concern regarding the potable water supply. Despite of its persistent behavior in the aquatic environment, a redox dependent removal at bank filtration sites with anaerobic aquifer passage was reported repeatedly but not elucidated in detail yet. The reductive transformation of CBZ was studied, using abiotic systems (catalytic hydrogenation, electrochemistry) as well as biologically active systems (column systems, batch degradation tests). In catalytic hydrogenation CBZ is gradually hydrogenated and nine transformation products (TPs) were detected by liquid chromatography high-resolution mass spectrometry. 10,11-Dihydro-CBZ ((2H)-CBZ) was the major stable product in these abiotic, surface catalyzed reduction processes and turned out to be not a precursor of the more hydrogenated TPs. In the biotic reduction processes the formation of (2H)-CBZ alone could not explain the observed CBZ decline. There, also traces of (6H)-CBZ and (8H)-CBZ were formed by microbes under anaerobic conditions and four phase-II metabolites of reduced CBZ could be detected and tentatively identified. Thus, the spectrum of reduction products of CBZ is more diverse than previously thought. In environmental samples CBZ removal along an anaerobic soil passage was confirmed and (2H)-CBZ was determined at one of the sites.
Water Quality Control, Technische Universität Berlin - Berlin Institute of Technology, Strasse des 17. Juni 135, 10623 Berlin, Germany. Electronic address: anne.koenig@tu-berlin.de.
Anne
A
König
Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
Cindy
C
Weidauer
Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
Bettina
B
Seiwert
Department of Analytical Chemistry, Helmholtz Centre for Environmental Research - UFZ, Permoserstrasse 15, 04318 Leipzig, Germany.
Thorsten
T
Reemtsma
Water Quality Control, Technische Universität Berlin - Berlin Institute of Technology, Strasse des 17. Juni 135, 10623 Berlin, Germany.
Tina
T
Unger
Water Quality Control, Technische Universität Berlin - Berlin Institute of Technology, Strasse des 17. Juni 135, 10623 Berlin, Germany.
Martin
M
Jekel
D000927:Anticonvulsants; D002220:Carbamazepine / Q000737:chemistry*; D002853:Chromatography, Liquid; D060587:Groundwater; D013058:Mass Spectrometry; D014874:Water Pollutants, Chemical / Q000737:chemistry
D000927:Anticonvulsants; D014874:Water Pollutants, Chemical; D002220:Carbamazepine
Electroreduction; Identification; Mass spectrometry; Transformation pathway; Zero valent iron