Fate of antibacterial spiramycin in river waters

摘要: Spiramycin, a widely used veterinary macrolide antibiotic, was found at traceable levels (nanograms per litre range) in Po River water (N-Italy). The aqueous environmental fate of this antibiotic compound studied through drug decomposition, the identification main and secondary transformation products (TPs), assessment mineralisation investigation TPs toxicity. Initially, laboratory experiments were performed, with aim stimulating antibacterial processes followed aquatic systems. identified employment liquid chromatography (LC)-mass spectrometry technique. Under illumination, spiramycin degraded rapidly transformed into numerous organic (intermediate) compounds, which 11 could be identified, formed five initial routes. These simulation verified situ to check mechanism previously supposed. sampled analysed (by LC-high-resolution mass spectrometry) eight sampling points. Among TPs, them also river water. Three seem direct photolysis process, while other two are indirect mediated by natural photo sensitisers. occurring system involved hydroxylation, demethylation detachment forosamine or mycarose sugars. Toxicity assays using Vibrio fischeri proved that even if did not exhibit toxicity, its proceeded formation toxic products.