Many lowland regions are afflicted with high phosphorus (P) peaks in rivers during the summer months. Static incubations of sediments have shown that reductive dissolution of ferric iron (Fe(III)) minerals in the sediment explain these P peaks. This study was set up to identify if that mechanism also dominates in a dynamic system, thereby testing the roles of water flow velocity and sediment Fe/P ratio. Decreasing flow velocity was suspected to lower the flux of dissolved oxygen (DO) towards the sediment. The role of the Fe(III)/P ratio was tested by amending iron-rich glauconite sand (GS) to the sediment, in this manner testing possible remediation techniques. Eight flumes (1.80 m long) were constructed with duplicates of four treatments of two laminar flow velocities over the sediment (0.05 m s⁻¹ or 0.15 m s⁻¹) that was either or not amended with GS (10% w/w). In all flumes a daily dose of sodium glutamate was added as a carbon source to mimic wastewater with high BOD, the flumes were operated for 28 days. A decreased velocity lowered the steady-state DO concentration and enhanced the sediment-water release of P by a factor 3. Sediment amendment with GS reduced solution P by factors 3 (low flow velocity) and 2 (high flow velocity). This effect is related to a combination of increasing binding sites for P and of lowering the DO consumption. These experimental data suggest that previously unexplained summer peaks of P in lowland rivers are related to low flow events that limit the DO flux. The internal loading of P requires management of DO in water and can be mitigated by enhancing sediment Fe.

在夏季，许多低地地区河流中的磷（P）峰值较高。沉积物的静态温育表明，沉积物中三价铁（Fe（III））矿物的还原溶解解释了这些P峰。进行这项研究的目的是确定该机制是否在动态系统中也占主导地位，从而测试水流速和沉积物Fe / P比的作用。降低流速被怀疑会降低溶解氧（DO）向沉积物的通量。Fe（III）/ P比的作用是通过将富铁青砂石砂（GS）修改为沉积物来测试的，以此方式测试可能的修复技术。构造了八个水槽（长1.80 m），对沉积物（0.05 ms ^-1或0.15 ms）上的两个层流速度的四个处理进行了四次重复处理^-1）被GS（10％w / w）修改或未修改。在所有水槽中，都添加了每日剂量的谷氨酸钠作为碳源，以模拟具有高BOD的废水，水槽运行了28天。降低的速度降低了P的稳态DO浓度，并使P的沉淀水释放增加了3倍。用GS进行的泥沙改良使P降低了3倍（低流速）和2倍（高流速）。这种效果与增加P的结合位点和降低DO的消耗有关。这些实验数据表明，低地河流先前无法解释的夏季P峰值与限制DO通量的低流量事件有关。磷的内部负载需要对水中的溶解氧进行管理，并且可以通过增加沉积物中的铁来减轻磷的含量。