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| Titel |
Hydrogeochemical alteration of groundwater due to a CO2 injection test into a shallow aquifer in Northeast Germany |
| VerfasserIn |
Frank Dethlefsen, Anita Peter, Götz Hornbruch, Hendrik Lamert, Dieter Garbe-Schönberg, Matthias Beyer, Peter Dietrich, Andreas Dahmke |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250094884
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| Publikation (Nr.) |
 EGU/EGU2014-10318.pdf |
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| Zusammenfassung |
| The accidental release of CO2 into potable aquifers, for instance as a consequence of a leakage out of a CO2 store site, can endanger drinking water resources due to the induced geochemical processes. A 10-day CO2 injection experiment into a shallow aquifer was carried out in Wittstock (Northeast Germany) in order to investigate the geochemical impact of a CO2 influx into such an aquifer and to test different monitoring methods. Information regarding the site investigation, the injection procedure monitoring setup, and first geochemical monitoring results are described in [1]. Apart from the utilization of the test results to evaluate monitoring approaches [2], further findings are presented on the evaluation of the geophysical monitoring [3], and the monitoring of stable carbon isotopes [4]. This part of the study focuses of the hydrogeochemical alteration of groundwater due to the CO2 injection test.
As a consequence of the CO2 injection, major cations were released, i.e. concentrations increased, whereas major anion concentrations – beside bicarbonate – decreased, probably due to increased anion sorption capacity at variably charged exchange sites of minerals. Trace element concentrations increased as well significantly, whereas the relative concentration increase was far larger than the relative concentration increase of major cations. Furthermore, geochemical reactions show significant spatial heterogeneity, i.e. some elements such as Cr, Cu, Pb either increased in concentration or remained at stable concentrations with increasing TIC at different wells. Statistical analyses of regression coefficients confirm the different spatial reaction patterns at different wells. Concentration time series at single wells give evidence, that the trace element release is pH dependent, i.e. trace elements such as Zn, Ni, Co are released at pH of around 6.2-6.6, whereas other trace elements like As, Cd, Cu are released at pH of 5.6-6.4.
[1] Peter, A., et al., Investigation of the geochemical impact of CO2; on shallow groundwater: design and implementation of a CO2; injection test in Northeast Germany. Environmental Earth Sciences, 2012. 67(2): p. 335-349.
[2] Dethlefsen, F., et al., Monitoring approaches for detecting and evaluating CO2 and formation water leakages into near-surface aquifers. Energy Procedia, 2013. 37(0): p. 4886-4893.
[3] Lamert, H., et al., Feasibility of geoelectrical monitoring and multiphase modeling for process understanding of gaseous CO2; injection into a shallow aquifer. Environmental Earth Sciences, 2012. 67(2): p. 447-462.
[4] Schulz, A., et al., Monitoring of a simulated CO2 leakage in a shallow aquifer using stable carbon isotopes. Environmental Science & Technology, 2012. 46(20): p. 11243-11250. |
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