In their recent paper “Integrating Bayesian Groundwater Mixing Modeling With On‐Site Helium Analysis to Identify Unknown Water Sources“, Andrea Popp and her Eawag colleagues studied a groundwater system used for drinking water production. The drinking water field needs to be protected from several potential sources of contamination by artificially controlling the groundwater flow. In view of these problems, the Eawag team identified the origins of the different groundwater components in the drinking water field and quantified their mixing ratios using a miniRUEDI by analysing He and other dissolved gases as natural tracers for the different groundwater components.
Eddie Banks from Flinders University took all his instruments to Laos to study the river/groundwater exchange over hundreds of kilometers along the Namn Ghum river. Take a look at his photos of how the very first miniRUEDI made by Gasometrix sniffs the waters!
In their recent paper “A Novel Approach To Quantify Air–Water Gas Exchange in Shallow Surface Waters Using High-Resolution Time Series of Dissolved Atmospheric Gases“, Uli Weber and his colleagues developed a new method to study and quantify the air-water gas exchange in a shallow surface waters. The method uses a miniRUEDI to quantify the natural variations of dissolved atmospheric gases in the water. The resulting high-resolution time series of dissolved gas concentrations in the water yield accurate gas exchange rates without adding artificial tracers.
In their recent paper “On-line monitoring of the gas composition in the full-scale emplacement experiment at Mont Terri (Switzerland)“, Yama Tomonaga and his colleagues at Nagra, Eawag and ETH Zurich used a miniRUEDI to study the dynamics and the fate of the gas species in a tunnel of a full-scale experiment targeted at radioactive waste disposal in Switzerland.
- An on-line gas monitoring has been implemented for the FE experiment at Mont Terri underground rock laboratory.
- The monitoring of gas species was performed successfully over several months.
- Rapid gas exchange occurs between drift backfilling and FE niche/host rock.
- Terrigenic gases (e.g., 4He, 40Ar, CH4, CO2) accumulated in the backfill pore space.
- Fast gas exchange partly explains the O2 removal from the backfill pore space.
Because of popular demand we summarised the most important features of the miniRUEDI in a datasheet document: download PDF document
HeliumOne, the Oxford Noble lab, and the University of Dar es Salaam are on the hunt for helium — and they will be using a miniRUEDI!
The foundation of Gasometrix GmbH as an Eawag Spin-Off was well received in the media. Tages Anzeiger and some other newspapers picked up the Eawag press release, and I got interviewed by Swiss Radio and Television for their Science Magazine. Here’s the interview (in German):
Eawag News about Gasometrix GmbH
Analyses of environmental gases which previously required months of laboratory work can now be carried out rapidly in the field. A group of Eawag scientists have developed a portable mass spectrometer allowing on-site measurements – and a spin-off has been created to commercialize the new system. (read the full article)
The following figure shows an m/z scan obtained from a miniRUEDI analysis of ambient air. The electron impact ionization energy of the ionizer (EE) was set to the default value of 70 eV for this measurement. Using lower EE values would reduce double ionisation. This chart is useful to assess the occurrence and importance of interferences of peak signals related to different gas species at the same m/z value.
Here’s an interactive world map of some miniRUEDI applications. Just click on the markers to learn more about these projects!