Publication Details

Category Text Publication
Reference Category Journals
DOI 10.1016/j.apgeochem.2019.04.009
Document accepted manuscript
Title (Primary) Dynamics of greenhouse gases in groundwater: hydrogeological and hydrogeochemical controls
Author Nikolenko, O.; Orban, P.; Jurado, A.; Morana, C.; Jamin, P.; Robert, T.; Knöller, K.; Borges, A.V.; Brouyѐre, S.
Journal Applied Geochemistry
Year 2019
Department CATHYD
Volume 105
Page From 31
Page To 44
Language englisch
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Keywords Greenhouse gases (GHGs); Groundwater; Indirect emissions; Agriculture; Stable isotope analysis
Abstract In this study the variability of greenhouse gases (GHGs) concentrations along lateral and vertical dimensions of the chalk aquifer located in the eastern part of Belgium was examined in order to understand its dependence on hydrogeological and hydrogeochemical conditions. Groundwater samples from 29 wells/piezometers were analyzed for concentrations of nitrous oxide (N2O), carbon dioxide (CO2), methane (CH4), major and minor elements and stable isotopes of nitrate (NO3), nitrous oxide (N2O), sulfate (SO42−) and boron (B). For lateral investigations, four zones with different environmental settings were identified (southern, central, north-eastern and northern). Groundwater was oversaturated with GHGs with respect to its equilibrium concentrations with the atmosphere in all zones, except the northern one, undersaturated in N2O (0.07 ± 0.08 μgN/L vs. 0.3 μgN/L). Vertical dimension studies showed the decrease in CO2 concentration and significant changes in both isotope signatures and concentration of N2O with depth. The production of N2O could be attributed to a combination of nitrification and denitrification processes occurring at different depths. CO2 concentration is controlled by the process of dissolution of carbonate minerals which constitute aquifer geology. CH4 is produced due to methanogenesis in deeper parts of the aquifer, though its thermogenic origin is also possible. Differences in hydrogeochemical settings and changing intensity of biogeochemical processes across the area and with depth have considerable effect on GHGs concentrations. Thus, before estimating GHGs fluxes at the groundwater–river interface insights obtained from larger-scale investigations are required in order to identify the representative spatial zones which govern GHGs emissions.
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Nikolenko, O., Orban, P., Jurado, A., Morana, C., Jamin, P., Robert, T., Knöller, K., Borges, A.V., Brouyѐre, S. (2019):
Dynamics of greenhouse gases in groundwater: hydrogeological and hydrogeochemical controls
Appl. Geochem. 105 , 31 - 44