CO2 Radiocarbon Analysis to Quantify Organic Contaminant Degradation, MNA, and Engineered Remediation Approaches
Abstract
This study combines CO2 radiocarbon measurements with CO2 flux measurements to quantify contaminant carbon conversion to CO2 and thus complete degradation. This project's objective is to combine CO2 respiration, CO2 radiocarbon content and a Zone of Influence (ZOI) model to calculate chlorinated hydrocarbon degradation occurring at real DoD contaminated sites. Radiocarbon analysis will measure the fraction of petroleum-source in the CO2 pool. To determine COI degradation rate, we will measure the CO2 production rate by circulating groundwater well headspace through a CO2 trap over time or use a passive trap suspended in the wells headspace. A well zone of influence (ZOI) can be calculated using process-based simulation models of gas transport in porous media (4). The ZOI model and CO2 production rate will be used to determine the overall CO2 production rate per soil unit. Given the fraction of CO2 derived from a petroleum-source and CO2 produced per soil unit (cubic meter for example), the contaminant degradation rate can be determined over both time and space. This will support all research needs outlined in the SERDP needs section (5, 6) enhancing management, assessing efficacy or fully quantifying natural attenuation capacities. This technology is straightforward and commercially-available, and will provide two key answers for site management and remediation efficacy (both active and passive) that have not been available: Is remediation occurring? We will be able to track the amount (percentage basis) of the degradation end product (CO2). On the basis of this one measurement, a site manager will be able to definitively state whether (bio)degradation is occurring or not. At what rate is the remediation occurring? By measuring the proportion of fossil fuel-derived CO2 and the CO2 production rate over time, we will be able to calculate the rate of (bio)degradation occurring on-site.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 30, 2020
- Accession Number
- AD1134905
Entities
People
- Jennifer Gonzalez
- Maria Vernet
- Michael T. Montgomery
- Richard H. Cuenca
- Thomas J. Boyd
- Yutaka Hagimoto
Organizations
- United States Naval Research Laboratory