Freshwater ecosystems, particularly those in agricultural areas, remain at risk of eutrophication due to anthropogenic inputs of nutrients. While community-based monitoring has helped improve awareness and spur action to mitigate nutrient loads, monitoring is challenging due to the reliance on expensive laboratory technology, poor data management, time lags between measurement and availability of results, and risk of sample degradation during transport or storage. In this study, an easy-to-use smartphone-based application (The Nutrient App) was developed to estimate ${\text{NO}}_3$ and ${\text{PO}}_4$ concentrations through the image-processing of on-site qualitative colorimetric-based results obtained via cheap commercially-available instantaneous test kits. The app was tested in rivers, wetlands, and lakes across Canada and relative errors between 30% (filtered samples) and 70% (unfiltered samples) were obtained for both ${\text{NO}}_3$ and ${\text{PO}}_4$. The app can be used to identify sources and hotspots of contamination, which can empower communities to take immediate remedial action to reduce nutrient pollution.

由于养分的人为输入，淡水生态系统，特别是农业地区的生态系统仍处于富营养化的风险中。尽管基于社区的监测有助于提高人们的认识并采取行动减少营养负荷，但由于对昂贵的实验室技术的依赖，数据管理不善，测量与结果可用性之间的时间滞后以及运输或运输过程中样品降解的风险，监测工作仍面临挑战存储。在这项研究中，开发了一个易于使用的基于智能手机的应用程序（Nutrient App）来估算${\text{没有}}_3$ 和 ${\text{PO}}_4$通过廉价的市售瞬时测试套件获得的基于现场定性比色法结果的图像处理来获得浓度。该应用程序已在加拿大的河流，湿地和湖泊中进行了测试，两者的相对误差都在30％（过滤后的样本）和70％（未过滤的样本）之间${\text{没有}}_3$ 和 ${\text{PO}}_4$。该应用程序可用于识别污染源和热点，从而使社区能够立即采取补救措施以减少营养物污染。