盐酸洛美沙星输入方式对水中反硝化过程的影响

Effects of Lomefloxacin Hydrochloride Input Modes on Denitrification Process in Water

为探究环境中抗生素输入方式对反硝化过程的影响,选择盐酸洛美沙星(LOM)为代表抗生素,以纳米乳化油为碳源,开展了LOM浓度(200 ng·L^(-1)和2 mg·L^(-1))与输入方式(一次输入和两次输入)不同组合条件下的反硝化模拟实验。结果表明:相同输入方式下,高浓度体系对NO^(-)_(3)-N还原的抑制率比低浓度体系高;相同浓度不同输入方式下,一次输入体系比两次输入体系对NO^(-)_(3)-N还原的抑制效果更强,半衰期更长,最大还原速率更小;此外,高浓度条件下受输入方式的影响更明显,表现为高浓度体系对NO^(-)_(3)-N还原的相对抑制率比低浓度体系高约25.9%。微生物数量、活性和丰富度分析结果显示:低浓度条件下微生物对LOM的响应受输入方式影响不显著,高浓度条件下一次输入体系比两次输入体系影响大;然而,微生物群落结构和抗性基因(ARGs)的变化与输入方式没有明显关系,这与群落结构及抗性基因响应具有滞后性有关。上述研究表明,在浓度较高的条件下,水土环境中由于抗生素输入模式不同引起的反硝化过程差异不可忽视。

To investigate the effects of antibiotic input modes on denitrification process in the environment,lomefloxacin hydrochloride(LOM)was selected as representative antibiotic,and nano-emulsified vegetable oil was used as carbon source to carry out denitrification simulation experiments.Different combination methods of LOM concentrations(200 ng·L^(-1) and 2 mg·L^(-1))and input modes(once-and twice-input)were used in the experiment.The results show that the inhibition on NO^(-)_(3)-N reduction in high-concentration system is higher than that in low-concentration system with the same input mode.Under the same concentration and different input modes,the inhibitory effect of once-input system on NO^(-)_(3)-N reduction is stronger than that of twice-input system,with longer half-lives and lower maximum reduction rate.In addition,the influence of input modes is more obvious in high concentration condition.The relative inhibition rate of high-concentration system on NO^(-)_(3)-N reduction is about 25.9%higher than that of low-concentration system.Also,the number,activity and richness of microorganisms confirm that once-input system have a greater impact than twice-input system under the high concentration condition.But there are no obviously response of microorganisms at low concentration condition.Furthermore,the changes of microbial community and ARGs are not significantly related to input modes,which are believed to be related to the delayed response of microbial community and ARGs.From the primary study,it is believed that the difference of denitrification process caused by the different input modes of antibiotics in soil and water environment could not be ignored,especially under the condition of high concentration.