Covatti Gustavo, Hoang Thi Ngoc Anh, Grischek Thomas
Dresden University of Applied Sciences, Friedrich-List-Platz 1, 01069 Dresden, Germany.
Dresden University of Applied Sciences, Friedrich-List-Platz 1, 01069 Dresden, Germany.
Sci Total Environ. 2023 Nov 20;900:165858. doi: 10.1016/j.scitotenv.2023.165858. Epub 2023 Jul 27.
Geogenic arsenic contamination of groundwater poses a health threat to millions of people worldwide, particularly in Asia. Riverbank filtration (RBF) is a pre-treatment technique that aims to improve surface water quality through natural processes during water infiltration before abstraction. A study in Hanoi, Vietnam is presented, where the water quality of 48 RBF wells from 5 large well fields located in the Pleistocene aquifer along the Red River was analyzed. >80 % of the wells had arsenic concentrations above the WHO limit of 10 μg/l. The riverbed sediment and riverbed pore-water from 23 sites along a stretch of 30 km of the Red River near the well fields was also analyzed. Muddy riverbeds were found to be a hotspot for arsenic release. Already at a 30 cm depth from the riverbed sediment surface, the pore-water at many sites had high concentrations of arsenic (>100 μg/l). Arsenic concentrations in the pore-water of sites where mud lenses were present in the riverbed were significantly higher compared to sites with sandy riverbeds. At well fields along stretches of the Red River where riverbed was mostly muddy, higher arsenic concentrations were found than at well fields where the riverbed was mostly sandy. This indicates that river muds deposition and river morphology can influence arsenic concentrations in the aquifer in Hanoi and potentially other RBF sites in regions with geogenic arsenic contamination. At the end, recommendations regarding site selection of new potential RBF wells in affected regions is given.
地下水中的原生砷污染对全球数百万人的健康构成威胁，在亚洲尤为严重。河岸过滤（RBF）是一种预处理技术，旨在通过取水前水渗透过程中的自然过程改善地表水水质。本文介绍了在越南河内进行的一项研究，该研究分析了位于红河沿岸更新世含水层的5个大型井场中48口河岸过滤井的水质。超过80%的井砷浓度高于世界卫生组织规定的10μg/l的限值。还分析了井场附近红河30公里河段沿线23个地点的河床沉积物和河床孔隙水。发现泥泞的河床是砷释放的热点。在距河床沉积物表面30厘米深处，许多地点的孔隙水中砷浓度很高（>100μg/l）。与沙质河床的地点相比，河床中存在泥质透镜体的地点孔隙水中的砷浓度显著更高。在红河沿岸河床大多为泥泞的河段的井场，发现的砷浓度高于河床大多为沙质的井场。这表明河泥沉积和河流形态会影响河内含水层以及地质成因砷污染地区其他潜在河岸过滤地点的砷浓度。最后，针对受影响地区新的潜在河岸过滤井的选址给出了建议。
