Djidja Roumaissa, Dewez David, Azzouz Abdelkrim
Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C 3P8, Canada.
Nanoqam, Department of Chemistry, University of Quebec at Montreal, H3C 3P8, Canada.
Chemosphere. 2025 Mar;372:144088. doi: 10.1016/j.chemosphere.2025.144088. Epub 2025 Jan 17.
Norfloxacin was ozonized in aqueous montmorillonite suspensions and the resulting toxicity on Lemna minor was investigated for understanding the impact of natural partial oxidation of antibiotics on clay-containing ecosystems. Ion-exchanged montmorillonites (Mt) were used as catalysts because of their large occurrence in soils and aquatic media, while Lemna minor, an aquatic macrophyte is regarded as a bioindicator highly responsive to ecotoxicity change in the environment. NOF solutions exhibit intrinsic toxicity on L. minor expressed in terms of fresh mass, frond number, chlorophyll content and production of reactive oxygen species. This toxicity was found to trigger through oxidative stress and was enhanced by ozonation. UV-Vis spectrophotometry and liquid chromatography coupled to mass spectrometry (LC-MS) showed that the toxicity specifically evolves in time according to the clay exchangeable cations, oxidation advancement and derivatives distribution, and confirmed the unavoidable formation of hydroxylated and acidic intermediates. The cleavage of the phenyl and pyridinyl groups appear to occur even in non-catalytic ozonation and generate potentially more toxic derivatives than the parent molecule with excessive oxidative stress and changes in the distribution of the photosynthetic pigments. Addition of Fe(II)Mt and Cu(II)Mt induced a more effective ozonation with, but with much less toxicity with Fe exchanged Mt catalyst. This research provides valuable insights into the environmental fate of antibiotics under aerobic conditions, and allows understanding their impact evolution on biodiversity, envisaging strategies targeting optimized water treatments with complete mineralization of organic pollutants.
诺氟沙星在蒙脱土水悬浮液中进行臭氧化处理，并研究了其对浮萍的毒性，以了解抗生素自然部分氧化对含粘土生态系统的影响。离子交换蒙脱土（Mt）因其在土壤和水生介质中大量存在而被用作催化剂，而水生大型植物浮萍被视为对环境生态毒性变化高度敏感的生物指示剂。诺氟沙星溶液对浮萍表现出内在毒性，可通过鲜重、叶状体数量、叶绿素含量和活性氧生成量来体现。发现这种毒性是由氧化应激引发的，并且臭氧化会增强这种毒性。紫外可见分光光度法和液相色谱 - 质谱联用（LC - MS）表明，毒性会根据粘土可交换阳离子、氧化进程和衍生物分布随时间特异性地演变，并证实了羟基化和酸性中间体的不可避免形成。即使在非催化臭氧化过程中，苯基和吡啶基的裂解似乎也会发生，并且与母体分子相比，会产生潜在毒性更强的衍生物，同时伴有过度的氧化应激和光合色素分布的变化。添加铁（II）蒙脱土和铜（II）蒙脱土可诱导更有效的臭氧化，但铁交换蒙脱土催化剂产生的毒性要小得多。这项研究为需氧条件下抗生素的环境归宿提供了有价值的见解，并有助于了解它们对生物多样性的影响演变，设想针对有机污染物完全矿化的优化水处理策略。
