Proposition de protocole de traçage adapté au karst de la craie

Gombert, Philippe

doi:10.1051/wqual/2007012

Cited by 3 publications

(5 citation statements)

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“…Since the injection induced an overpressure, this phenomenon is probably due to the retention of part of the tracers within the chalk's porous matrix (which is of micrometric dimension), and then to their slow release when the natural flow of the aquifer resumed. This phenomenon has previously been demonstrated at other sites where the chalk shows dual porosity [29,30]. Thus, in the injection well, the tracer concentration remained higher than the background noise for 12.9 days for lithium and helium and until the end of the monitoring (t ≥ 49.9 days) for uranine, on which date the analyses still showed the presence of 0.29 µg•L −1 of this tracer.…”

Section: Tracing Of the Injected Watersupporting

confidence: 74%

Monitoring Scheme for the Detection of Hydrogen Leakage from a Deep Underground Storage. Part 2: Physico-Chemical Impacts of Hydrogen Injection into a Shallow Chalky Aquifer

et al. 2021

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This paper presents the results of an experiment to simulate a sudden and brief hydrogen leak from a potential deep geological storage site. A 5 m3 volume of groundwater was extracted, saturated with hydrogen, and then reinjected into the aquifer. Saturating the water with hydrogen caused a decrease in the oxidation-reduction potential, the dissolved gas content (especially O2 and CO2), the electrical conductivity, and the concentration of alkaline earth bicarbonate ions and a slight increase in pH. These changes are observed until 20 m downstream of the injection well, while the more distant piezometers (from 30 to 60 m) are not significantly affected. During this experiment, no indicators of the development of chemical or biochemical reactions are observed, because of the rapid transfer of the dissolved hydrogen plume through the aquifer and its significant dilution beyond 10 m downstream of the injection well. Here, hydrogen behaved as a conservative element, reacting very slightly or not at all. However, this experiment demonstrates the existence of direct and indirect impacts of the presence of hydrogen in an aquifer. This experiment also highlights the need to adapt the monitoring of future underground hydrogen storage sites.

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Section: Tracing Of the Injected Watersupporting

confidence: 74%

Monitoring Scheme for the Detection of Hydrogen Leakage from a Deep Underground Storage. Part 2: Physico-Chemical Impacts of Hydrogen Injection into a Shallow Chalky Aquifer

et al. 2021

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“…The nature and the dose of tracers used in this work come from previous statistical studies of tracer tests realized in the western part of the Paris Basin, called Normandy (Gombert, 2007(Gombert, , 2008. This is a 10,000 km² chalky area that contains nearly 500 groundwater wells and karstic springs used for water supply (Fig.…”

Section: Area Presentationmentioning

confidence: 99%

“…In the context of limestone (Käss, 1998) as well as in the context of Normandy chalk (Gombert, 2007), fluorescent and ionic tracers are the most common tracers. The fluorescent tracers are mainly used because of their moderate cost, their low detection level and their easy detection method (Goldscheider et al, 2008).…”

Section: Nature Of Tracersmentioning

confidence: 99%

“…The required dose is generally calculated by empirical formulas (Field, 2003) mainly dependent on the nature of the tracer, the distance to trace, the flow of the breakthrough point and/or the concentration expected at this point. The most commonly used dose is approximately 1 kg of tracer per 1 km of distance to trace (Gombert, 2007(Gombert, , 2008. This dose is mainly valid for uranine, and several authors have proposed a correction factor for other tracers: 1 (Gombert, 2008) to 4 (Käss, 1998;Benischke et al, 2007) for sulforhodamine B, 2 for Tinopal (Gombert, 2008), 2.4 (Gombert, 2008) to 15 (Käss, 1998;Benischke et al, 2007) for naphthionate.…”

Section: Dose Of Tracersmentioning

confidence: 99%

“…In this case, the injected tracer undergoes the same treatment as the water before entering the distribution system and reaching the tap of the consumer (Gombert, 2007;Goldscheider et al, 2008). Submitted to the action of drinking water treatment agents, which are mostly strong oxidizers (chlorine, bleach, chlorine dioxide, ozone, bromine, and UV radiations), the fluorescent tracer can degrade to byproducts.…”

Section: Introductionmentioning

confidence: 99%

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Toxicity of fluorescent tracers and their degradation byproducts

Gombert¹,

Biaudet²,

Seze³

et al. 2017

IJS

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Abstract:Tracer tests are frequently used to delineate catchment area of water supply springs in karstic zones. In the karstic chalk of Normandy, the main tracers used are fluorescent: uranine, sulforhodamine B, naphtionate, and Tinopal®. In this area, a statistical analysis shows that less than half of the injected tracers joins the monitored restitution points and enters the drinking water system where they undergo chlorination. Most of the injected tracers is absorbed in the rock matrix or is thrown out of the aquifer via karstic springs: then it can join superficial waters where it is degraded due to the sun and air action. The paper presents firstly the laboratory degradation of a first batch of fluorescent tracers in contact with chlorine, in order to simulate their passage through a water treatment system for human consumption. A second batch of the same tracers is subjected to agents of natural degradation: ultraviolet illumination, sunlight and air sparging. Most tracers is degraded, and toxicity and ecotoxicity tests (on rats, daphniae and algae) are performed on degradation byproducts. These tests do not show any acute toxicity but a low to moderate ecotoxicity. In conclusion, the most used fluorescent tracers of the Normandy karstic chalk and their artificial and natural degradation byproducts do not exhibit significant toxicity to humans and the aquatic environment, at the concentrations generally noted at the restitution points.

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The influence of geological structure on chalk karst aquifer function and its consequences for the protection of drinking-water supply; examples from Normandy, France

Hauchard

Turban²,

Leclerq

2022

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The implementation of new groundwater tracer tests to the chalky karst plateau of the northwestern end of the Paris Basin, combined with a critical review of previous tracer test investigations, makes it possible to characterize the role of karsts in relation to many structural features. The impact of tectonic structures and lithology on the development and evolution of the karst networks is analysed. The consequences for drinking-water supplies and its protection are examined.

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Proposition de protocole de traçage adapté au karst de la craie

Cited by 3 publications

References 0 publications

Monitoring Scheme for the Detection of Hydrogen Leakage from a Deep Underground Storage. Part 2: Physico-Chemical Impacts of Hydrogen Injection into a Shallow Chalky Aquifer

Monitoring Scheme for the Detection of Hydrogen Leakage from a Deep Underground Storage. Part 2: Physico-Chemical Impacts of Hydrogen Injection into a Shallow Chalky Aquifer

Toxicity of fluorescent tracers and their degradation byproducts

The influence of geological structure on chalk karst aquifer function and its consequences for the protection of drinking-water supply; examples from Normandy, France

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