Traces of World War I in groundwater: perchlorate contamination of the chalk aquifer in NE France

Autor: Feifei Cao, Jaunat, Jessy J., Alexandra Conreux, Julien HUBERT, Nicolas Devau, Patrick Ollivier
Přispěvatelé: Groupe d'Étude sur les Géomatériaux et Environnements Naturels, Anthropiques et Archéologiques - EA 3795 (GEGENAA), Université de Reims Champagne-Ardenne (URCA)-SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Maison des Sciences Humaines de Champagne-Ardenne (MSH-URCA), Université de Reims Champagne-Ardenne (URCA)-Université de Reims Champagne-Ardenne (URCA), Bureau de Recherches Géologiques et Minières (BRGM) (BRGM), CAO, Feifei
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: 46th IAH congress :Groundwater management and governance – coping with water scarcity
46th IAH congress :Groundwater management and governance – coping with water scarcity, Sep 2019, MALAGA, Spain
HAL
Popis: International audience; Perchlorate is an environmental contaminant of growing concern due to its potential human health effectsand widespread occurrence in surface water and groundwater. It is considered potentially toxic even at lowconcentrations (> 4 ppb) as an endocrine disruptor, especially for fetuses and infants. Analyzes have highlightedpresence of perchlorate in drinking water of Champagne-Ardenne (NE France) with two suspectedsources: a military source related to the WWI (World War I) and an agricultural one related to past use ofChilean nitrates.In order to define the origin and fate of perchlorate in groundwater, a study area of 500 km2 has been selectedeast of Reims, where drinking water catchments of the chalk aquifer are concerned with perchlorate contamination.Chalk groundwater flow and geochemistry are monitored for 2 years from June 2017 to June 2019 at 35sampling points including boreholes, springs and rivers (mainly form chalk aquifer drainage). Water samplesare collected monthly to determine the major and trace elements contents, stable water isotopes, perchlorateand organic pyrotechnic molecules. Perchlorate were detected at almost all sampling points (32 of 35) with amaximum value of 63 ppb and an average value of 11 ppb. High levels of perchlorate (> 4 ppb) were detectedmainly downstream of the Monronvilliers military camp, where quantities of ammunitions were used, storedand destroyed during and after the WWI. Statistical analysis shows no significant correlation between perchlorateand other major ions. The isotopic signature of perchlorate was analyzed and showed a synthetic origin,proving for the first time the military source of contamination in this area. In addition, groundwater datingusing CFCs and SF6 indicated an average residence time of < 30 years, implying that perchlorate contaminationis related to sources that may still subsist in the subsoil after the WWI (e.g. unexploded ammunitions)rather than military activities during the conflict. Perchlorate concentrations are relatively stable with timefor most points except for decreases observed in September 2017 and 2018. Stable isotopic analysis of waterand monitored groundwater table showed that the chalk aquifer is recharged by precipitation mainly duringthe winter season. Therefore, the decrease of perchlorate levels could possibly be explained by the very fewrecharge and low groundwater table in September, as less perchlorate is dissolved and transferred into theaquifer. This research provides insights on a combined use of hydraulic, geochemical and isotopic approachesto study the origin and transfer of contamination in chalk groundwater. The chalk aquifer properties and thelong-term influence of the WWI on groundwater quality in NE France are better clarified, with the aim toprovide appropriate recommendations in terms of water management.
Databáze: OpenAIRE
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