Real time in situ dissolved gases monitoring in groundwater by CF-MIMS for hydrogeology

International audienceDissolved gases are useful tools in hydrogeology. They inform us on physical and biogeochemical processes along the flow paths of groundwater (noble gases temperature, excess air, redox processes, groundwater ages,...). The sampling and measurement of dissolved gases are often complex and require sometimes long and costly analytical methods. Recently, field membrane inlet mass spectrometer (MIMS) technologies have been developed and optimized to environmental studies. We present here our "continuous flow" MIMS (CF-MIMS) for field measurements of dissolved gases: H2, He, Ne, Ar, N2, Kr, Xe, CH4, N2O, O2 and CO2. Calibration, optimization and limitations of the measurements are presented. The results of a gas tracer experiment and a real time dissolved gases profile in borehole are presented. This new high frequency field measurement technique offers new information for hydrogeological studie