Institute of Hydraulic Engineering and Water Resources Management, Technische Universität Wien, E222/2, Karlsplatz 13, 1040 Vienna, Austria; Centre for Water Resource Systems, Technische Universität Wien, Karlsplatz 13, 1040 Vienna, Austria.
Institute of Hydraulic Engineering and Water Resources Management, Technische Universität Wien, E222/2, Karlsplatz 13, 1040 Vienna, Austria; Centre for Water Resource Systems, Technische Universität Wien, Karlsplatz 13, 1040 Vienna, Austria.
Sci Total Environ. 2019 Feb 1;649:212-223. doi: 10.1016/j.scitotenv.2018.08.300. Epub 2018 Aug 24.
Riverbank filtration (RBF) systems along rivers are widely used as public water supplies. In these systems, many organic micropollutants (OMPs) are attenuated, but some compounds have shown to be rather persistent. Their fate and transport has been studied in RBF sites along lakes and small rivers, but not extensively along large and dynamic rivers. Therefore, the influence of flood events on OMP behavior in these large and dynamic RBF sites was investigated. Monthly samples were taken from surface- and groundwater up to a distance of 900 m from the riverbank of the Danube from March 2014 till May 2016. Two flood events were sampled more extensively nearby the river. Results showed that changes in flow conditions in the river not only caused changes in OMP concentrations, but also in their load. It was seen that the load of benzotriazole, carbamazepine and sulfamethoxazole in the river increased with increasing river discharges. After a relatively long, oxic groundwater passage, several OMPs were reduced. In contrast to previous work, we found that benzotriazole was almost fully removed under oxic conditions. When entering the aquifer, benzotriazole concentrations were significantly reduced and at a distance of 550 m from the river, >97% was degraded. Carbamazepine and sulfamethoxazole showed relatively persistent behavior in the aquifer. The concentrations measured during flood events were in the same range as seasonal sampling. Furthermore concentrations in the groundwater were higher during these events than in the Danube and can reach further into the aquifer. During flood events some highly degradable compounds (i.e. diclofenac) were found up to a distance of 24 m from the river. These results implied that drinking water utilities with RBF wells in oxic, alluvial aquifers located close to highly dynamic rivers need to consider a potential reduction in groundwater quality during and directly after flood events.
河流滨岸过滤（RBF）系统被广泛应用于公共供水。在这些系统中，许多有机微量污染物（OMPs）得到了衰减，但有些化合物表现出相当的持久性。它们在湖泊和小河的 RBF 地点的命运和迁移已经被研究过，但在大型和动态河流中并没有得到广泛研究。因此，研究了洪水事件对这些大型和动态 RBF 地点 OMP 行为的影响。从 2014 年 3 月到 2016 年 5 月，每月从多瑙河滨岸表面和地下水取样，距离滨岸 900 米。在河流附近更广泛地采样了两次洪水事件。结果表明，河流中流量条件的变化不仅导致 OMP 浓度发生变化，还导致其负荷发生变化。可见，苯并三唑、卡马西平和磺胺甲恶唑在河流中的负荷随河流流量的增加而增加。在经过一段较长的有氧地下水通道后，几种 OMP 被还原。与之前的工作不同，我们发现苯并三唑在有氧条件下几乎完全被去除。当进入含水层时，苯并三唑浓度显著降低，在距离河流 550 米处，降解率超过 97%。卡马西平和磺胺甲恶唑在含水层中表现出相对持久的行为。洪水事件期间测量的浓度与季节性采样相同。此外，这些事件期间地下水的浓度高于多瑙河，并且可以进一步进入含水层。在洪水事件期间，在距离河流 24 米的范围内发现了一些高度可降解的化合物（如二氯芬酸）。这些结果表明，位于高度动态河流附近的含氧冲积含水层中具有 RBF 井的饮用水供应公司需要考虑洪水事件期间和之后地下水质量的潜在降低。
