Environmental Geosciences, University of Basel, CH-4056, Basel, Switzerland.
Entsorgungsverband Saar (EVS), Mainzer Str. 261, 66121, Saarbrücken, Germany.
Sci Rep. 2017 Jun 7;7(1):2981. doi: 10.1038/s41598-017-03055-7.
For the first time, speciation of Fe, Mn, Zn, Ni, Cu and Pb was determined along the profiles of 8 constructed wetlands (CWs) consisting of fluviatile sand (Fluv), clinopyroxene-dominated lava sand (Cl-LS) and zeolite-dominated lava sand (Ze-LS), aiming at quantifying metal behaviour in CWs and the impact caused by different filter materials. With the exception of Mn, which underwent reductive dissolution, CWs were sinks for the studied metals. Metal accumulation rates differed in the following order: Ze-LS ≥ Cl-LS > Fluv CWs, reflecting the highest metal adsorption capacity and the lowest hydraulic conductivity of Ze-LS. Sequential extraction data indicated the highest metal mobility (readily mobilised and adsorbed fractions summing up to ~60%) in Fluv CWs, implying a higher risk of metal release into adjacent environments if Fluv from CWs will be improperly disposed after usage. Zinc and Ni were transported into the deeper CW layers to a larger extent than Cu and Pb, reflecting adsorption affinity to all filter materials in the order of Pb > Cu > Zn > Ni. Therefore, understanding metal speciation and mobility in such materials is crucial when they are considered for application as filters in CWs.
首次针对由河流砂（Fluv）、斜长岩为主的玄武岩砂（Cl-LS）和沸石为主的玄武岩砂（Ze-LS）组成的 8 个人工湿地（CWs）剖面，定量研究了铁、锰、锌、镍、铜和铅的分馏情况，以量化 CWs 中金属的行为及其不同过滤材料造成的影响。除了发生还原溶解的锰之外，CWs 都是研究金属的汇。金属积累速率的顺序为：Ze-LS≥Cl-LS＞Fluv CWs，反映了 Ze-LS 具有最高的金属吸附能力和最低的水力传导率。顺序提取数据表明，Fluv CWs 中金属的迁移率最高（可轻易移动和吸附的部分总计约 60%），这意味着如果 CWs 中的 Fluv 在使用后处理不当，将有更高的金属释放到相邻环境的风险。锌和镍比铜和铅更多地被输送到 CWs 的深层，这反映了它们对所有过滤材料的吸附亲和力顺序为 Pb＞Cu＞Zn＞Ni。因此，当将这些材料考虑作为 CWs 中的过滤器时，了解其金属形态和迁移率至关重要。
