Département Ressources aquatiques et eau potable

Ressources aquatiques & eau potable

Nous étudions les processus essentiellement physiques et chimiques des eaux souterraines, des eaux de surface et de l’eau potable. Notre recherche fondamentale et nos études appliquées sur les ressources aquatiques, la pollution et le traitement des eaux contribuent notablement à une gestion durable de l’eau dans un contexte national et international.

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Publications

Lightfoot, A., Brennwald, M. S., Stopelli, E., AdvectAs project members, & Kipfer, R. (2023). The role of (noble)gases in an As contaminated aquifer. In A. van der Wal, A. Ahmad, B. Petrusevski, J. Weijma, D. Savic, P. van der Wens, … R. Naidu (Eds.), Arsenic in the environment. Proceedings. Proceedings of the 8th international congress and exhibition on arsenic in the environment (As2021) (pp. 23-24). Boca Raton FL: Taylor & Francis. , Institutional Repository

Arsenic (As) contamination of groundwater remains a problem for many of the river deltaic areas
in South-East Asia; where concentrations regularly exceed the 10 mg/L currently recommended by the Word Health Organisation. The focus of this study is to determine inert and reactive gas concentrations in groundwaters at a location where As mobilization is active, to constrain the sites hydrogeology in a highly reducing environment. The small village of Van Phuc, Vietnam, presents an ideal opportunity for such research as is it well studied and accessible, however the As dynamics here are still not well understood. Gas concentrations in 21 wells at varying depths and locations were analysed in Van Phuc, Vietnam, with the miniRUEDI – a portable mass spectrometer (miniRUEDI, Gasometix GmbH, Switzerland) capable of measuring noble gases: He, Ar, Kr, and reactive gases:
CO2, CH4, N2 and O2 in water. First results show As concentrations are highest where CH4 production is observed. Furthermore, evidence of a gaseous CH4 phase being produced within the aquifer is shown through excessive depletion of N2, Ar and Kr elements. Such in-situ formation of gas bubbles can alter the permeability of the aquifer and modify groundwater flow. Simultaneous measurement of both inert and reactive gas species can therefore give an insight to groundwater dynamics of As contaminated aquifers
Wu, R., Podgorski, J., Berg, M., & Polya, D. A. (2023). Pseudo contour maps from logistic regression modelling: case study of groundwater arsenic distribution in Gujarat state, India. In A. van der Wal, A. Ahmad, B. Petrusevski, J. Weijma, D. Savic, P. van der Wens, … R. Naidu (Eds.), Arsenic in the environment. Proceedings. Proceedings of the 8th international congress and exhibition on arsenic in the environment (As2021) (pp. 95-96). doi:10.1201/9781003317395-40, Institutional Repository

Logistic regression modelling is a widely used prediction method to generate probability maps
of groundwater arsenic exceeding a selected threshold concentration. In this study, we converted logistic regression modelled probability maps to a pseudo contour map which comprehensively integrated important information of several probability maps of groundwater arsenic concentrations in Gujarat state, India. The pseudo contour map of groundwater arsenic concentrations clearly and intuitively indicates high groundwater arsenic concentrations (>10 mg/L) occurring in Kachchh District and Banas Kantha District and shows groundwater arsenic concentrations in northern and central Gujarat to be slightly higher than near the western
and eastern borders of the state. The cutoffs, where sensitivity equals specificity, is one of the most appropriate criteria of diagnosis of continuous probability results, better ensuring the accuracy of the generation of a pseudo contour map. However, the probability cutoff of each contour is likely different, so that the generated map is pseudo-contour rather than a contour map.
Stopelli, E., Duyen, V. T., Mai, T. T., Trang, P. T. K., Viet, P. H., Lightfoot, A., … Berg, M. (2023). Interplay of As (im)mobilisation processes in groundwater: learning from hydrochemical investigations. In A. van der Wal, A. Ahmad, B. Petrusevski, J. Weijma, D. Savic, P. van der Wens, … R. Naidu (Eds.), Arsenic in the environment. Proceedings. Proceedings of the 8th international congress and exhibition on arsenic in the environment (As2021) (pp. 21-22). doi:10.1201/9781003317395-9, Institutional Repository

Millions of people worldwide are exposed to arsenic (As) contaminated groundwater. Despite decades of research and evidence of As mobilisation in anoxic aquifers being caused by reductive dissolution of iron minerals, the mechanisms behind the local scale variability of dissolved As remains unclear. Therefore, the trans-disciplinary AdvectAs project investigates the environmental behaviour and spatial heterogeneity of dissolved As in groundwater in the Red River delta, Vietnam. Here we present the results from hydrochemical and water isotope investigations. In particular, we will show how the large As variability (0.1–510 mg/L) is related to consecutive As (im)mobilisation steps, depending on site hydrology, geology and the interplay of Fe, Mn, S and organic matter cycles. Such complexity of (im)mobilisation processes can be simplified in 5 major hydro(geo) chemical zones, providing a conceptual tool with potential for application at other sites in Asia affected by geogenic As contamination of groundwater.
Podgorski, J., & Berg, M. (2023). Second-generation global risk map of groundwater arsenic contamination. In A. van der Wal, A. Ahmad, B. Petrusevski, J. Weijma, D. Savic, P. van der Wens, … R. Naidu (Eds.), Arsenic in the environment. Proceedings. Proceedings of the 8th international congress and exhibition on arsenic in the environment (As2021) (pp. 3-4). doi:10.1201/9781003317395-1, Institutional Repository

Naturally occurring arsenic in groundwater affects millions of people around the world. In order to assess the extent of this problem, we have used machine learning to create a global prediction map of groundwater arsenic greater than 10 mg/L. The resulting model includes already known arsenic-affected areas as well as new potentially contaminated areas. Combining the global arsenic prediction model with household groundwater-usage statistics, we estimate that 94–220 million people are potentially exposed to high arsenic concentrations in groundwater. As groundwater is increasingly utilized to support a growing population and buffer against increasing water scarcity due to a changing climate, this model will help raise awareness, identify suitable areas for safe wells and guide where testing for arsenic should be prioritized.

Nouvelles

Un dépôt final pour les déchets nucléaires doit pouvoir résister aux périodes glaciaires

12 novembre 2024

Un site de dépôt final pour les déchets nucléaires doit être sûr, même si, dans un avenir lointain, les glaciers des Alpes devaient à nouveau avancer jusqu’au Plateau suisse. Pour cette raison, la Nagra a fait étudier des sédiments déposés dans les profondeurs d’anciens lacs glaciaires: ces couches sédimentaires ont environ 600’000 ans et sont donc bien plus anciennes que la dernière période glaciaire, survenue il y a environ 24’000 ans. Et bonne nouvelle pour la Nagra: il semble que depuis lors, les couches de roche sous-jacentes n’ont jamais été érodées par la glace.

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Projets de recherche

The project investigates what measures are most effective in influencing a river corridor so that river restoration and groundwater flow systems can help to mitigate the effects of floods and droughts.

Record Catchment
This project facilitates the exchange of data, maps and information on geogenic contaminants (focussing on arsenic and fluoride) via the web-based Groundwater Assessment Platform (GAP)

Groundwater Assessment Platform (GAP)

Plus de projets de recherche