Product Overview Sampling Process Case Studies Product Resources
How the process works
Fossil Fuel traps are deployed for 5-28 days
Fossil Fuel traps are processed and analyzed
A comprehensive report is received
What is included
Analysis and Corrections
Travel Blank
To ensure accuracy, each shipment of Fossil Fuel Traps includes a Travel Blank. The Travel Blank acts as a control to capture CO₂ due to handling and travels to and from the site. The processed Travel Blank also accounts for a relatively small mass of CO₂ present in the sorbent from the manufacturing process.
The Travel Blank is never opened; when shipped, the travel blank captures any CO₂ to which the samples are exposed. When the other Fossil Fuel Traps are deployed, the Travel Blank is kept in a "safe bag" to ensure no unnecessary CO₂ absorption takes place. The Travel Blank is taken out of the 'safe bag' prior to the return shipment to again capture environmental CO₂. The carbon levels of the Travel Blank are analyzed and are then subtracted from the carbon levels of the rest of the analyzed samples: Blank Corrected Results = Raw Results - Travel Blank.
Carbon Analysis
After a field deployment, the Fossil Fuel Traps are sent back to E-Flux. The sorbent is recovered from the trap housing, dried, homogenized, and analyzed for carbonate and fossil fuel carbon content.
E-Flux uses industry-accepted practices and methodologies, including quality assurance and quality control protocols. In combination with our proprietary technology, the carbonate and ¹⁴C analyses are based on two ASTM methods:
D4373-14, Standard Test Method for Rapid Determination of Carbonate Content of Soils
D6866-18, Standard Test Methods for Determining the Biobased Content of Solid, Liquid, and Gaseous Samples Using Radiocarbon Analysis
Radiocarbon Analysis
Total CO₂ flux captured by the Fossil Fuel Trap represents a two-source model, with CO₂ being collected from natural soil organic matter (modern carbon) and from LNAPL (fossil fuel carbon). The bottom sorbent layer in each Fossil Fuel Trap undergoes quantitative radiocarbon (¹⁴C) analysis in order to determine the amount of fossil fuel-derived carbon in the sample.
Modern CO₂ fluxes can be significant, and are subtracted off of the net CO₂ flux measurement to provide an accurate biodegradation estimate.
Fossil fuel carbon can be differentiated from modern carbon using the carbon isotope ¹⁴C, which has a half-life of about 5700 years. Because they are millions of years old, fossil fuels contain an undetectable amount of ¹⁴C. E-Flux therefore analyzes sorbent samples for their ¹⁴C content to determine the amount of modern carbon in a sample and the percentage of the total CO₂ flux that is fossil fuel-derived.
For more information on ¹⁴C dating see "Basis for ¹⁴C Analysis."
Our Report
Report tables have four parts: fossil fuel trap deployment description, raw results, blank-corrected results, and blank-corrected ¹⁴C results. Each report includes sample-specific grams of modern- and fossil fuel-derived CO₂ as well as a fossil fuel-based LNAPL loss rate.
All generated data is confidential between E-Flux and the customer. Site data shared with E-Flux for discussion purposes are not shared with new customers unless a single client orders multiple batches of Fossil Fuel Traps for the same site and wishes a more in-depth report. E-Flux will provide in-depth discussion of report results at the customer’s request, but we will not provide consulting advice; use of data is ultimately up to the customer.
