抄録
Levofloxacin (LVFX) is a potent synthetic antibacterial agent of the third-generation fluoroquinolones (FQs) that inhibits the bacterial enzymes DNA gyrase and topoisomerase IV. Because of its extensive usage, LVFX may enter the water environment through wastewater effluent.
In the present study, to verify the effects of LVFX on aquatic life by chlorination which is used in the disinfection process of sewage treatment, an evaluation using the algal growth inhibition test was conducted. In addition, scan data and fragmentation patterns were acquired by liquid chromatography/tandem mass spectrometry (LC/MS/MS) to clarify the change of chemical structure of LVFX caused by chlorination.
The results of the algal growth inhibition test showed that the Toxicity Unit (TU) of the chlorinated sample was 1600 times higher than the hazard quotient (HQ) for the amount of LVFX in the chlorinated sample. From scan data, m/z 362 (P362), which was presumed to be the unaltered substance (LVFX), and m/z 336 (D336) and m/z 279 (D279), which were presumed to be byproducts of LVFX, were detected as the protonated molecules [M+H] + . It was conjectured that D336 and D279 had been caused by the chlorination which changed the chemical structure of position 10 of LVFX, the N′-methyl- piperazinyl group. The toxicity of the chlorinated sample may have been caused by substances other than LVFX such as chlorinated byproducts.
