Field Real-Time Monitoring of Ammonia Nitrogen in Different Water Bodies Using GPMCS
Ammonia nitrogen (NH3-N) is a common water pollutant that can induce eutrophication and threaten aquatic ecosystems and human health. Accurate monitoring is essential for water safety. This study applied a self-developed gas-permeable membrane-based conductivity sensor (GPMCS) for real-time in-situ monitoring of NH3-N in two water bodies. In the Qunying River (surface river water), GPMCS captured concentration fluctuations linked to pump operations and sewage intrusion, with mean inlet and outlet concentrations of 4.67 and 3.42 mg/L, respectively. In Swan Lake (landscape aquaculture water), concentrations reached up to 11.16 mg/L, with site means of 6.42 and 7.04 mg/L, influenced by aquaculture activities, weather, and location. GPMCS results correlated strongly with national standard methods (r1=0.8132, r2=0.7483), confirming accuracy and reliability. Compared to existing techniques, GPMCS offers high selectivity, strong anti-interference, portability, no sample pretreatment, low cost, and environmental friendliness, making it suitable for long-term in-situ monitoring. This technology provides robust support for sustainable water environment management.