Brienza M., Manasfi R., Sauvetre A., Chiron Serge. (2020). Nitric oxide reactivity accounts for N-nitroso-ciprofloxacin formation under nitrate-reducing conditions. Water Research, 185, 116293 [8 p.]. ISSN 0043-1354.
Titre du document
Nitric oxide reactivity accounts for N-nitroso-ciprofloxacin formation under nitrate-reducing conditions
Water Research, 2020,
185, 116293 [8 p.] ISSN 0043-1354
The formation of N-nitroso-ciprofloxacin (CIP) was investigated both in wastewater treatment plants including nitrification/denitrification stages and in sludge slurry experiments under denitrifying conditions. The analysis of biological wastewater treatment plant effluents by Kendrick mass defect analysis and liquid chromatography - high resolution - mass spectrometry (LC-HRMS) revealed the occurrence of N-nitroso-CIP and N-nitroso-hydrochlorothiazide at concentration levels of 34 +/- 3 ng/L and 71 +/- 6 ng/L, respectively. In laboratory experiments and dark conditions, produced N-nitroso-CIP concentrations reached a plateau during the course of biodegradation experiments. A mass balance was achieved after identification and quantification of several transformation products by LC-HRMS. N-nitroso-CIP accounted for 14.3% of the initial CIP concentration (20 mu g/L) and accumulated against time. The use of 4,5-diaminofluorescein diacetate and superoxide dismutase as scavengers for in situ production of nitric oxide and superoxide radical anion respectively, revealed that the mechanisms of formation of N-nitroso-CIP likely involved a nitrosation pathway through the formation of peroxynitrite and another one through codenitrification processes, even though the former one appeared to be prevalent. This work extended the possible sources of N-nitrosamines by including a formation pathway relying on nitric oxide reactivity with secondary amines under activated sludge treatment.
Plan de classement
Sciences fondamentales / Techniques d'analyse et de recherche [020]
;
Pollution [038]
;
Hydrologie [062]