Case Study


E-Flux Fossil Fuel Traps were developed at the Center for Contaminant Hydrology at Colorado State University over a five-year period after researchers there recognized the limitations of other CO2 flux measurement approaches and saw the need for time-averaged measurements. To determine the effectiveness of Fossil Fuel Traps, researchers conducted two laboratory experiments and a field study, the results of which were published by Groundwater in 2014. Loss rates measured by the traps in the field study indicated that LNAPL on the tested field site was naturally degrading at a rate of 13,400 to 130,000 L/ha/yr. In addition, the experiments and field study demonstrated three things:

  • The E-Flux Fossil Fuel Trap's sorbent quantitatively recovers CO2 up to the manufacturer's limit of 30% saturation.
  • The trap design and deployment do not create preferential pathways or skewed results.
  • E-Flux Fossil Fuel Traps are a practical and easy-to-use application for measuring soil as flux.

Additional Information

Field Site Map and Fossil Fuel Trap Survey Results

Field site map example

The area of the circles is proportional to measured CO2 flux (JCO2_TOTAL, µmol/m2/s). The color of the circles is related to calculated (blank-corrected) LNAPL loss (JCO2_LNAPL, L/Ha/year) as shown on the linearly increasing color ramp. Locations shown as hollow circles did not significantly exceed background CO2 flux. The light gray area shows the approximate extent of on-site LNAPL as estimated by laser induced fluorescence (LIF) survey. General groundwater flow is toward the river. (Source: McCoy, K., Zimbron, J., Sale, T., & Lyverse, M. 2014. "Measurement of Natural Losses of LNAPL Using Fossil Fuel Traps". Groundwater. doi:10.1111/gwat.12240)