Knox Anna Sophia, Paller Michael H, Nelson Eric A, Specht Winona L, Halverson Nancy V, Gladden John B
Savannah River National Lab., Savannah River Site, 773-42A, Aiken, SC 20808, USA.
J Environ Qual. 2006 Sep 13;35(5):1948-59. doi: 10.2134/jeq2006.0017. Print 2006 Sep-Oct.
The A-01 wetland treatment system (WTS) is a surface flow wetland planted with giant bulrush [Schoenoplectus californicus (C.A. Mey.) Palla] that is designed to remove Cu and other metals from the A-01 National Pollution Discharge Elimination System (NPDES) effluent at the Savannah River Site near Aiken, SC. Copper, Zn, and Pb concentrations in water were usually reduced 60 to 80% by passage through the treatment system. The Cu concentrations in the wetland sediments increased from about 4 to 205 and 796 mg kg(-1), respectively, in the organic and floc sediment layers in cell 4A over a 5-yr period. Metal concentrations were higher in the two top layers of sediment (i.e., the floc and organic layers) than in the deeper inorganic layers. Sequential extraction was used to evaluate remobilization and retention of Cu, Pb, Zn, Mn, and Fe in the wetland sediment. Metal remobilization was determined by the potentially mobile fraction (PMF) and metal retention by the recalcitrant factor (RF). The PMF values were high in the floc layer but comparatively low in the organic and inorganic layers. High RF values for Cu, Zn, and Pb in the organic and inorganic layers indicated that these metals were strongly bound in the sediment. The RF values for Mn were lower than for the other elements especially in the floc layer, indicating low retention or binding capacity. Retention of contaminants was also evaluated by distribution coefficient (Kd) values. Distribution coefficient (Kd) values were lower for Cu and Zn than for Pb, indicating a smaller exchangeable fraction for Pb.
A-01湿地处理系统（WTS）是一种表面流湿地，种植了巨型芦苇[加州灯心草（C.A. Mey.）帕拉]，旨在从南卡罗来纳州艾肯附近萨凡纳河场地的A-01国家污染排放消除系统（NPDES）废水中去除铜和其他金属。通过该处理系统，水中的铜、锌和铅浓度通常可降低60%至80%。在5年的时间里，湿地沉积物中细胞4A的有机层和絮凝物沉积层中的铜浓度分别从约4毫克/千克增加到205毫克/千克和796毫克/千克。沉积物的两个顶层（即絮凝层和有机层）中的金属浓度高于较深的无机层。采用连续萃取法评估湿地沉积物中铜、铅、锌、锰和铁的再迁移和保留情况。金属的再迁移通过潜在可移动部分（PMF）来确定，金属的保留通过难降解因子（RF）来确定。絮凝层中的PMF值较高，但有机层和无机层中的相对较低。有机层和无机层中铜、锌和铅的高RF值表明这些金属在沉积物中结合牢固。锰的RF值低于其他元素，尤其是在絮凝层中，表明其保留或结合能力较低。还通过分配系数（Kd）值评估污染物的保留情况。铜和锌的分配系数（Kd）值低于铅，表明铅的可交换部分较小。
