The proliferation of emerging contaminants (ECs) in the environment poses a major threat to the safety of reuse water. However, many ECs exist for which no corresponding control standards have been established. Here, we used polarity reversal to construct a biocathode sensor capable of early warning of ECs biotoxicity in aerobic reuse water with low organic concentrations. The baseline current and sensitivity of the biosensor in response to formaldehyde were enhanced by 25% and 23% using microbial fuel cell effluent as the inoculum. The microbial community explained that the inoculum primarily influenced the performance of the biosensor by modulating species abundance, function and interactions. More importantly, the successfully commissioned biocathode sensor demonstrated rapid warning capability (Response time less than 1.3 h) for ECs such as fluoride, disinfection by-products and antibiotics in an actual landscape reuse system. Further, the sensor could quantify the concentration of a single known contaminant. Our study demonstrated a method for rapid early warning of ECs in an oxygen-rich, low-organics environment, promoting innovative development of monitoring technologies for water ecology and environmental safety.

环境中新兴污染物（EC）的扩散对回用水的安全构成了重大威胁。然而，许多 EC 尚未建立相应的控制标准。在这里，我们利用极性反转构建了一种生物阴极传感器，能够对有机浓度较低的好氧回用水中 ECs 的生物毒性进行预警。使用微生物燃料电池流出物作为接种物，生物传感器对甲醛的基线电流和灵敏度分别提高了 25% 和 23%。微生物群落解释说，接种物主要通过调节物种丰度、功能和相互作用来影响生物传感器的性能。更重要的是，成功调试的生物阴极传感器表现出快速预警能力（响应时间小于1. 3 h) 对于实际景观再利用系统中的氟化物、消毒副产物和抗生素等 EC。此外，传感器可以量化单一已知污染物的浓度。我们的研究展示了一种在富氧、低有机物环境中快速预警ECs的方法，促进了水生态和环境安全监测技术的创新发展。