Photo-degradation of the antimicrobial ciprofloxacin at high pH: identification and biodegradability assessment of the primary by-products.
Photo-treatment for the removal of pharmaceuticals in effluents is a topic currently under discussion. In some countries effluents from hospitals are directly emitted into open ditches without any further treatment and with very little dilution. Under such circumstances photo-degradation in the environment can occur. However, photo-degradation does not necessarily end up with the complete mineralization of a chemical. Therefore, photo-product biodegradability and toxicity against environmental bacteria is of interest. Hospital effluents have often a pH around 9. Therefore, photo-oxidation (150W medium-pressure Hg-lamp, batch reactor) of ciprofloxacin (CIP) was studied at pH 9. The primary elimination of CIP was monitored and structures of photo-products were assessed by liquid chromatography ion trap mass spectrometry (LC-MS/MS). Five compounds were identified as probable products of photo-defluorination, -decarboxylation and loss of the piperazine moiety. These photo-products were not biodegradable in the Closed Bottle test - OECD 301D. They did not affect Vibrio fisheri in the applied concentrations.
Department of Chemistry of the Federal University of Santa Maria, 97105-900 Santa Maria-RS, Brazil.
Tibiriçá G
TG
Vasconcelos
Danielle M
DM
Henriques
Armin
A
König
Ayrton F
AF
Martins
Klaus
K
Kümmerer
D000890:Anti-Infective Agents / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D002851:Chromatography, High Pressure Liquid; D002939:Ciprofloxacin / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry / Q000633:toxicity; D052918:Environmental Restoration and Remediation; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D010782:Photolysis; D053719:Tandem Mass Spectrometry
D000890:Anti-Infective Agents; D004785:Environmental Pollutants; D002939:Ciprofloxacin