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Spatial and temporal evolution of groundwater arsenic contamination in the Red River delta, Vietnam: Interplay of mobilisation and retardation processes

Stopelli, Emiliano; Duyen, Vu T.; Mai, Tran T.; Trang, Pham T.K.; Viet, Pham H.; Lightfoot, Alexandra; Kipfer, Rolf; Schneider, Magnus; Eiche, Elisabeth; Kontny, Agnes; Neumann, Thomas; Glodowska, Martyna; Patzner, Monique; Kappler, Andreas; Kleindienst, Sara; Rathi, Bhasker; Cirpka, Olaf; Bostick, Benjamin; Prommer, Henning; Winkel, Lenny H.E.; ... mehr

Abstract:
Geogenic arsenic (As) contamination of groundwater poses a major threat to global health, particularly in Asia. To mitigate this exposure, groundwater is increasingly extracted from low-As Pleistocene aquifers. This, however, disturbs groundwater flow and potentially draws high-As groundwater into low-As aquifers.

Here we report a detailed characterisation of the Van Phuc aquifer in the Red River Delta region, Vietnam, where high-As groundwater from a Holocene aquifer is being drawn into a low-As Pleistocene aquifer. This study includes data from eight years (2010–2017) of groundwater observations to develop an understanding of the spatial and temporal evolution of the redox status and groundwater hydrochemistry.

Arsenic concentrations were highly variable (0.5–510 μg/L) over spatial scales of <200 m. Five hydro(geo)chemical zones (indicated as A to E) were identified in the aquifer, each associated with specific As mobilisation and retardation processes. At the riverbank (zone A), As is mobilised from freshly deposited sediments where Fe(III)-reducing conditions occur. Arsenic is then transported across the Holocene aquifer (zone B), where the vertical intrusion of evaporative water, likely enriched in dissolved organic matter, promotes methanogenic conditions and further release of As (zone C). ... mehr

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Verlagsausgabe §
DOI: 10.5445/IR/1000117459
Veröffentlicht am 28.02.2020
Originalveröffentlichung
DOI: 10.1016/j.scitotenv.2020.137143
Scopus
Zitationen: 4
Web of Science
Zitationen: 3
Cover der Publikation
Zugehörige Institution(en) am KIT Institut für Angewandte Geowissenschaften (AGW)
Publikationstyp Zeitschriftenaufsatz
Publikationsmonat/-jahr 05.2020
Sprache Englisch
Identifikator ISSN: 0048-9697
KITopen-ID: 1000117459
Erschienen in The science of the total environment
Verlag Elsevier
Band 717
Seiten Art.-Nr.: 137143
Schlagwörter Groundwater hydrochemistry, Water isotopes, Arsenic geochemistry, Reductive dissolution, Redox transition, Methanogenic conditions
Nachgewiesen in Scopus
Web of Science
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