Lomefloxacin—Occurrence in the German River Erft, Its Photo-Induced Elimination, and Assessment of Ecotoxicity

Abstract

Pharmaceuticals in waters represent a worldwide problem of today. Advanced oxidation processes (AOPs) are being researched for elimination of the ecological hazard. Among the substances, the fluoroquinolone antibiotic lomefloxacin was selected for investigation in this study. Lomefloxacin (LOM) was found in the German river Erft. Near and far ultraviolet (UVA, UVC) radiation were used as AOPs and compared for efficiency depending on pH, water matrix, and catalysts. Chemical kinetics description revealed that UVC at pH 8-9 led to the fastest degradation of LOM. The catalysts hydrogen peroxide and titanium dioxide had only limited influence on the degradation rate. Seven novel transformation products were structurally identified by high-resolution higher-order mass spectrometry. Ecotoxicity of the novel and known compounds was assessed by quantitative structure-activity relationship (QSAR) analysis. In addition, irradiation time dependent minimal, and half-maximal inhibitory concentrations (MIC, IC 50 ) of LOM solutions were determined and suggested as ecotoxicological hazard indicators. From MIC and kinetic rate constants, the irradiation time required for compound and activity removal could be predicted.

Metoprolol and Its Degradation and Transformation Products Using AOPs—Assessment of Aquatic Ecotoxicity Using QSAR

“…The recorded c-t -curves were best described by sequence or subsequence follow-up reaction of first-order [ 25 , 28 ].…”

“…The degradation curves and kinetic profiles of the degradation products were calculated and fitted mathematically using the curve fitting toolbox within the software MatLab R2020a (MathWorks, Natick, MA, USA). All kinetic profiles and degradation curves were computed according to first-order kinetic models, consecutive and subsequent follow-up reaction models [ 25 , 26 , 27 , 28 , 29 ].…”

Ecotoxicity Assessment of Photoinduced Imidacloprid Degradation Using HPLC-HRMS, QSAR and Ecotoxicity Equivalents

“…Mathematical treatment followed chemical kinetics as described in detail in previous studies. [26,27,[38][39][40] QSAR…”

“…Occasionally, degradation products from AOPs were suspected to be more toxic than the original substances [23,24]. During an AOP, the concentration-time (c-t) curves were often monitored and the structures of degradation or transformation products were often elucidated by high performance-liquid chromatography (HPLC) coupled to high-resolution mass spectrometry (HRMS) and higher order mass spectrometry (MS n ) [25][26][27][28] As matrix, pure water or water containing natural organic matters such as humic acid and fulvic acid were used [29,30].…”

Water and Wastewater Treatment: Selected Topics

“…Voigt et al [6] in their publication researched a very interesting and current topic concerning the degradation of the antibiotic Lomefloxacin (LOM), detected in the German river Erft. The methodology of near and far ultraviolet (UVA, UVC) radiation was used as AOPs and examined in relation to pH, water matrix, and catalysts.…”