Short-term exposure to triclocarban alters microbial community composition and metabolite profiles in freshwater biofilms

Triclocarban (TCC), an emerging contaminant in water environments, threatens aquatic ecosystems, yet its impacts remain insufficiently elucidated. This study investigates the effects of TCC exposure on mature freshwater biofilms. TCC was found to inhibit biofilm activity by examining the surface morphology and identifying live/dead cells of biofilms. The responses of the biofilm microbial community and metabolites to TCC were investigated. The results indicate that the biofilm bacterial community structure was altered upon TCC exposure at both concentrations. Notably, functionally bacterial groups associated with carbon cycling were compromised, whereas the relative abundance of bacterial groups involved in nitrogen cycling was increased. Metabolomic analysis highlights significant disruptions in carbon metabolism-related pathways induced by TCC. Despite acute toxicity, biofilms exhibit regulatory responses by shaping amino acid and lipid metabolism to mitigate environmental stresses. Overall, short-term exposure to TCC produced acute toxicity to biofilms, but biofilms were able to regulate community structure and metabolic levels to maintain oxidative homeostasis and retain activity. Importantly, different TCC concentrations induce diverse toxicity mechanisms and detoxification strategies in biofilms. This study provides a better understanding of risk assessment and policy control of TCC in water environments.

三氯卡班（Triclocarban, TCC）是一类广泛存在于水环境中的新兴污染物，对水生生态系统构成严重威胁，但其具体生态影响仍未得到充分阐明。本研究探究了三氯卡班暴露对成熟淡水生物膜的影响效应：通过观测生物膜表面形貌并鉴定其活/死细胞状态，证实三氯卡班可抑制生物膜活性；同时分析了生物膜微生物群落与代谢物对三氯卡班暴露的响应特征。结果表明，两种实验浓度的三氯卡班暴露均会改变生物膜的细菌群落结构。值得关注的是，与碳循环相关的功能细菌类群丰度显著受损，而参与氮循环的细菌类群相对丰度则呈上升趋势。代谢组学分析显示，三氯卡班暴露会显著干扰碳代谢相关通路。尽管三氯卡班具有急性毒性，但生物膜可通过调控氨基酸与脂质代谢以缓解环境胁迫，展现出适应性调节响应。整体而言，短期三氯卡班暴露会对生物膜造成急性毒性损伤，但生物膜能够通过调控群落结构与代谢水平维持氧化稳态并保留自身活性。尤为重要的是，不同浓度的三氯卡班会在生物膜中诱导差异化的毒性机制与解毒策略。本研究可为水环境中三氯卡班的风险评估与政策管控提供更为深入的理论依据。