Daily CO2 Flux Changes
Ma, Jie, et al. "An inorganic CO2 diffusion and dissolution process explains negative CO2 fluxes in saline/alkaline soils." Scientific reports 3 (2013): 2025.
A robust and accurate site map is the foundation for efficient remediation. However, most testing techniques are not specific to petroleum-based contaminants, nor do they take into consideration atmospheric variability over time.
To help show why this is an issue, these graphs show nine locations monitored continuously for CO2 flux for a 24-hour period. The sine curves indicate how fluxes can change throughout the day as ambient pressure changes drive gases in and out of the soil.
To solve this problem, E-Flux Map Traps use multiple measurement techniques for petroleum-based contaminated sites. Map Traps utilize isotopic carbon dating techniques to provide a binary (yes/no) indication of LNAPL presence at MT testing points. The MT also measure total carbon over a two-week period, allowing for a time-averaged estimate that accounts for environmental variations such as temperature, barometric pressure and tidal changes. The best way to avoid daily fluctuations, such as barometric pumping, is to utilize the Map Trap technology and test at your site for multiple days in order to time-average the results.
Map Traps are shipped to the client and deployed for two weeks at ground level in a grid pattern across the entire contaminated area. (These passive flux measurement MT require no power source and cause minimal soil disturbance.) After deployment, the Map Traps are returned to E-Flux for a qualitative (yes/no) analysis on isotopic carbon (14C). In addition, total carbon is analyzed by averaging the results from the two-week deployment. Site-specific results are then sent to the client in a confidential report within 20 working days.
|Map Trap and Field Components
||Map Trap Delineation Example