Müller Beat, Stierli Ruth, Gächter René
Swiss Federal Institute for Environmental Science and Technology, Eawag, CH-6047, Kastanienbaum, Switzerland.
J Environ Monit. 2008 Jul;10(7):817-20. doi: 10.1039/b806465b. Epub 2008 Jun 12.
The concentration of dissolved reactive phosphorus (DRP) in rivers can change intermittently within minutes depending on the weather and water discharge (Q), or activities in the watershed. Accordingly, accurate estimation of the annual DRP load requires frequent sampling or even continuous monitoring, which is laborious and cost-intensive. We present the design and laboratory evaluation of a new, robust, low-cost, low-tech device based on passive samplers (P-traps). The traps use Fe-(oxy)hydroxide coated quartz sand as an adsorbent enclosed in a vertical grid of individual cells separated from the river water by filter membranes. They are inexpensive, easy to handle, resistant to repeated desiccation and immersion and exposable for several months. They permit estimation of discharge dependent time weighted average DRP concentrations (C-Q relationships) and annual P loads of rivers characterized by highly variable DRP concentrations with a relative accuracy of +/- 3%.
河流中溶解态活性磷（DRP）的浓度可在数分钟内随天气、水流量（Q）或流域内活动而间歇性变化。因此，准确估算年度DRP负荷需要频繁采样甚至连续监测，这既费力又成本高昂。我们展示了一种基于被动采样器（P型捕集器）的新型、坚固、低成本、低技术含量装置的设计及实验室评估。这些捕集器使用涂有氢氧化铁（羟基氧化物）的石英砂作为吸附剂，封装在由滤膜与河水隔开的单个单元格的垂直网格中。它们价格低廉、易于操作、耐反复干燥和浸泡，且可暴露数月。它们能够估算依赖流量的时间加权平均DRP浓度（C-Q关系）以及DRP浓度高度可变河流的年度磷负荷，相对准确度为±3%。
