Fate of Enrofloxacin in Lake Sediment: Biodegradation, Transformation Product Identification, and Ecotoxicological Implications

Various pharmaceutical drugs are being detected in different environmental compartments such as surface waters, groundwater, and sediment; a major concern since they are biologically active substances which can interfere with biological systems affecting the native biota. Among these drugs, antimicrobials are especially worrisome mainly due to the development of bacterial resistance. The aims of this study were to investigate if enrofloxacin, an emergent antibiotic pollutant, could be biodegraded in lake sediment, identify its break down products and to determine if these products have antimicrobial properties or are toxic. Three biodegradation products were identified and the antibiotic susceptibility assay proved that the products formed did not display antibiotic effects. Ecotoxicity testing with green algae suggested that the degradation products do not cause adverse effects statistically. However, it is suggested that further investigations are needed to identify the mechanism of degradation and the microbes involved.