Tracking selenium in the Chalk aquifer of ...
Document type :
Article dans une revue scientifique: Article original
Title :
Tracking selenium in the Chalk aquifer of northern France: Sr isotope constraints
Author(s) :
Cary, Lise [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Benabderraziq, Hind [Auteur]
Laboratoire Génie Civil et Géo-Environnement [Béthune] [LGCgE]
Elkhattabi, Jamal [Auteur]
École polytechnique universitaire de Lille [Polytech Lille]
Gourcy, Laurence [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Parmentier, Marc [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Picot, Julie [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Khaska, M. [Auteur]
Laboratoire GIS
Laurent, Alexandra [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Négrel, Philippe [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Bureau de Recherches Géologiques et Minières [BRGM]
Benabderraziq, Hind [Auteur]
Laboratoire Génie Civil et Géo-Environnement [Béthune] [LGCgE]
Elkhattabi, Jamal [Auteur]
École polytechnique universitaire de Lille [Polytech Lille]
Gourcy, Laurence [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Parmentier, Marc [Auteur]

Bureau de Recherches Géologiques et Minières [BRGM]
Picot, Julie [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Khaska, M. [Auteur]
Laboratoire GIS
Laurent, Alexandra [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Négrel, Philippe [Auteur]
Bureau de Recherches Géologiques et Minières [BRGM]
Journal title :
Applied Geochemistry
Pages :
70-82
Publisher :
Elsevier
Publication date :
2014-07-30
ISSN :
0883-2927
English keyword(s) :
selenium
strontium isotopes
chalk aquifer
groundwater
Lille
strontium isotopes
chalk aquifer
groundwater
Lille
HAL domain(s) :
Planète et Univers [physics]/Sciences de la Terre/Géochimie
Sciences de l'environnement/Milieux et Changements globaux
Sciences de l'environnement/Milieux et Changements globaux
English abstract : [en]
Groundwater at the southern and eastern edges of France's Paris Basin has a selenium content that at times exceeds the European Framework Directive's drinking-water limit value of 10 µg/L. To better understand the dynamics ...
Show more >Groundwater at the southern and eastern edges of France's Paris Basin has a selenium content that at times exceeds the European Framework Directive's drinking-water limit value of 10 µg/L. To better understand the dynamics of the Chalk groundwater being tapped to supply the city of Lille and the Se origins, we used a combination of geochemical and isotopic tools. Strontium isotopes, coupled with Ca/Sr, Mg/Sr and Se/Sr ratios, were used to identify the main groundwater bodies and their mixings, with the Mg/Sr ratio constraining a ternary system. Groundwater in the agricultural aquifer-recharge zone represents a first end-member and displays the youngest water ages of the catchment along with the highest strontium isotopic signature (0.7084) and low Se contents. Anaerobic groundwater constitutes a second major end-member affected by water-rock interactions over a long residence time, with the lowest strontium isotopic signature (0.7079) and the lowest Se content, its low SF6 content confirming the contribution of old water. Se-rich groundwater containing up to 30 µg/L of Se represents a third major end-member, with an intermediate Sr isotopic ratio, and is mainly constrained by the clayey Se-rich formation overlying the Chalk aquifer. The spatial and temporal Se variability in the groundwater is clearly linked to the presence of this formation identified as Tertiary and also to the hydrological conditions; saturation of the Se-rich clays by oxygenated groundwater enhances Se mobility and also Sr adsorption onto the clays. This multi-tool study including Sr isotopes successfully identified the Se origins in the aquifer and has led to a better understanding of the regional mixing and processes affecting the Chalk groundwater.Show less >
Show more >Groundwater at the southern and eastern edges of France's Paris Basin has a selenium content that at times exceeds the European Framework Directive's drinking-water limit value of 10 µg/L. To better understand the dynamics of the Chalk groundwater being tapped to supply the city of Lille and the Se origins, we used a combination of geochemical and isotopic tools. Strontium isotopes, coupled with Ca/Sr, Mg/Sr and Se/Sr ratios, were used to identify the main groundwater bodies and their mixings, with the Mg/Sr ratio constraining a ternary system. Groundwater in the agricultural aquifer-recharge zone represents a first end-member and displays the youngest water ages of the catchment along with the highest strontium isotopic signature (0.7084) and low Se contents. Anaerobic groundwater constitutes a second major end-member affected by water-rock interactions over a long residence time, with the lowest strontium isotopic signature (0.7079) and the lowest Se content, its low SF6 content confirming the contribution of old water. Se-rich groundwater containing up to 30 µg/L of Se represents a third major end-member, with an intermediate Sr isotopic ratio, and is mainly constrained by the clayey Se-rich formation overlying the Chalk aquifer. The spatial and temporal Se variability in the groundwater is clearly linked to the presence of this formation identified as Tertiary and also to the hydrological conditions; saturation of the Se-rich clays by oxygenated groundwater enhances Se mobility and also Sr adsorption onto the clays. This multi-tool study including Sr isotopes successfully identified the Se origins in the aquifer and has led to a better understanding of the regional mixing and processes affecting the Chalk groundwater.Show less >
Language :
Anglais
Peer reviewed article :
Oui
Audience :
Internationale
Popular science :
Non
Source :
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