RAPID: Assessing the ecosystem impact of drinking water orthophosphate addition on urban watersheds

匹兹堡市正计划添加腐蚀抑制剂（例如，正磷酸盐-PO 43 #8722;），于2019年3月底添加到其生产的7000万加仑饮用水（DW）中，以对抗铅服务线的铅浸出。计划的添加率比目前DW和城市河流中活性磷（P）的水平高2-3个数量级。磷浓度的这种实质性变化，以及匹兹堡的DW管网由于泄漏而损失了估计1500万加仑/天的事实，表明磷浓度升高可能会渗透到地下水中，并最终影响城市河流的健康。本快速反应研究（RAPID）项目将评估添加PO 43 #8722;前后从DW管道和水文连接的城市河流收集的水中微生物生态、水化学和营养物质的变化。本快速反应研究的主要目标是确定匹兹堡DW管道系统中添加PO 43 #8722;是否会影响水文连接的城市河流中的生态和地球化学循环。在添加PO43#8722;之前和之后，将分别从城市河流和DW管道位置采集8次水样。通过进行全面的水化学分析，微生物群落表征以及与PO 43 #8722;积累和固氮相关的特定属和物种的量化，科学家们将观察是否发生大规模的生态或营养变化。同样，藻类营养限制的研究将提供深入了解PO 43 #8722;添加后的城市溪流水的富营养化潜力。总的来说，这项研究将有助于回答基本的生态问题，有关泄漏的DW基础设施如何影响营养循环和水文连接的城市河流的水生生态系统。该奖项反映了NSF的法定使命，并已被认为是值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估的支持。

The city of Pittsburgh is planning to add corrosion inhibitors (e.g., orthophosphate -PO43−), at the end of March 2019 to the 70 million gallons of drinking water (DW) it produces, to combat lead leaching from lead service lines. The planned rate of addition is 2-3 orders of magnitude higher than current levels of reactive phosphorus (P) in DW and urban streams. This substantial change in P concentration, alongside the fact that Pittsburgh's DW pipe network loses an estimated 15 million gallons/day due to leaks, suggests that elevated concentrations of P are likely to infiltrate into groundwater and could ultimately impact the health of urban streams. This Rapid Response Research (RAPID) project will assess changes in the microbial ecology, water chemistry and nutrient availability in water collected from DW pipes and hydrologically connected urban streams before and after PO43− addition.The primary goal of this RAPID is to determine whether PO43− addition in the Pittsburgh DW pipe system will impact the ecology and geochemical cycling in hydrologically connected urban streams. Water samples will be collected from urban streams and DW pipe locations eight times before and eight times after PO43− addition. By performing comprehensive water chemistry analysis, microbial community characterization and quantification of specific genera and species linked to PO43− accumulation and nitrogen fixation, the scientists will observe whether broad-scale ecological or nutritional shifts occur. Likewise, algal nutritional limitation studies will provide insight into the eutrophication potential of urban stream water after PO43− addition. Overall, the study will help answer fundamental ecological questions relating to how leaking DW infrastructure can impact nutrient cycling and aquatic ecosystems in hydrologically connected urban streams.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.