Quantification of conservative and reactive transport using a single groundwater tracer test in a fractured media
Résumé
dentification of biogeochemical reactions in aquifers and determining kinetics is important for the prediction
of contaminant transport in aquifers and groundwater management. Therefore, experiments accounting for both
conservative and reactive transport are essential to understand the biogeochemical reactivity at field scale.
This study presents the results of a groundwater tracer test using the combined injection of dissolved conservative
and reactive tracers (He, Xe, Ar, Br-, O
2
and NO
3
-) in order to evaluate the transport properties of a fractured
media in Brittany, France.
Dissolved gas concentrations were continuously monitored in situ with a CF-MIMS (Chatton et al, 2016) allowing
a high frequency (1 gas every 2 seconds) multi-tracer analysis (N2, O
2
, CO
2
, CH4, N2O, H2, He, Ne, Ar, Kr, Xe)
over a large resolution (6 orders of magnitude). Along with dissolved gases, groundwater biogeochemistry was
monitored through the sampling of major anions and cations, trace elements and microbiological diversity.
The results show breakthrough curves allowing the combined quantification of conservative and reactive transport
properties. This ongoing work is an original approach investigating the link between heterogeneity of porous
media and biogeochemical reactions at field scale.
Eliot Chatton, Thierry Labasque, Je ́roˆme de La Bernardie, Nicolas Guihe ́neuf, Olivier Bour and Luc
Aquilina; Field Continuous Measurement of Dissolved Gases with a CF-MIMS: Applications to the Physics and
Biogeochemistry of Groundwater Flow; Environmental Science & Technology, in press, 2016.