Chemistry and Biochemistry Dep., Florida Atlantic Univ., Boca Raton, FL, 33431, USA.
Applied Sciences Bureau, South Florida Water Management District, West Palm Beach, FL, 33406, USA.
J Environ Qual. 2021 Sep;50(5):1171-1183. doi: 10.1002/jeq2.20278. Epub 2021 Aug 25.
Stormwater treatment areas (STAs) are constructed wetlands established to capture phosphorus (P) from agricultural runoff before reaching the Florida Everglades. Retained P is primarily stored in wetland soils and sediments generated through a collection of interrelated physical, chemical, and biological processes. The amount of P and other elements (Al, Ca, Cu, Fe, Mg, Mn, Pb, and Zn) retained in the flocculent (floc) and recently accreted soil (RAS) horizons from a relic agricultural ditch within Cell 4S of STA-1E were compared with the surrounding marsh soils (upstream and downstream sites of the ditch). The amount of P retained in the ditch was significantly greater than the surrounding marsh soils and for all the elements in the floc horizon and five of the nine elements in the RAS horizon, suggesting that different processes or process rates influenced accumulation. Phosphorus species in the floc and RAS sediment horizons were identified and quantified using P nuclear magnetic resonance (NMR) spectroscopy and total P determined by microwave plasma-optical emission spectroscopy. In general, P forms were dominated by orthophosphate, sugar phosphates, nucleotides, DNA, and pyrophosphate, with varying relative abundances of species. Total P concentration significantly decreased from upstream to downstream of the ditch by an average of 28 and 35% for floc and RAS soils, respectively. The relatively high P accrual rate within the ditch suggested that relic ditches perpendicular to flow could reduce P transport to downstream soils and sediments and, in turn, help maintain low P levels in overlying water.
雨水处理区（STAs）是为了在到达佛罗里达大沼泽地之前从农业径流中捕获磷（P）而建立的人工湿地。截留的 P 主要储存在湿地土壤和沉积物中，这些土壤和沉积物是通过一系列相互关联的物理、化学和生物过程产生的。在 STA-1E 单元 4S 的一个遗留农业沟渠中，从絮状（floc）和最近积累的土壤（RAS）层中保留的 P 和其他元素（Al、Ca、Cu、Fe、Mg、Mn、Pb 和 Zn）的量与周围沼泽土壤（沟渠上下游位置）进行了比较。沟渠中保留的 P 量明显大于周围的沼泽土壤，而且在絮状层中的所有元素和 RAS 层中的九个元素中的五个元素中都是如此，这表明不同的过程或过程速率会影响元素的积累。使用 P 核磁共振（NMR）光谱法和微波等离子体 - 光学发射光谱法测定了絮状和 RAS 沉积物层中 P 的形态和总量。一般来说，P 形态主要由正磷酸盐、糖磷酸盐、核苷酸、DNA 和焦磷酸盐组成，各种形态的相对丰度不同。总的来说，P 浓度在絮状和 RAS 土壤中分别从沟渠上游到下游平均下降了 28%和 35%。沟渠内相对较高的 P 积累速率表明，与流向垂直的遗留沟渠可以减少 P 向下游土壤和沉积物的运输，从而有助于维持上覆水体中的低 P 水平。
