miniRUEDI used to quantify air-water gas exchange in surface waters – without adding tracer gases!

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.

miniRUEDI used for gas monitoring in a full-scale experiment targeted at underground radioactive waste disposal

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.

Highlights:

  • 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.

Use of miniRUEDI Instruments in Air/Water Exchange Studies in Small Streams

In their recent paper “In-situ mass spectrometry improves the estimation of stream reaeration from gas-tracer tests“, Julia Knapp and her colleagues at Uni Tübingen and Eawag used two miniRUEDI instruments to study air/water exchange in small streams.

Highlights:

  • Determination of gas-exchange rates in streams from gas-tracer testsQuantification of gas tracers using a portable gas-equilibrium mass spectrometer
  • Reliable estimation of reaeration rates from krypton and propane injections
  • In-situ analysis avoids gas loss and improves the determination of reaeration rates

Gasometrix in the news!

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)

Air spectrum measured with miniRUEDI

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.