Keywords: emulsion, hydraulic properties, soil stabilization, surface runoff potential, seed germination, ecosystem impact
Project Description
Project Summary:
The transport of radionuclides from contaminated soils can occur through several pathways including surface runoff, infiltration, and windblown dust transport. In cooperation with the Navy Facilities Engineering Service Center (NFESC), Encapco Technologies LLC is seeking to quantify the efficacy of a proprietary, organic-based emulsion treatment on the transport of radionuclides through the water transport pathway. The project field sites are divided into two locations. The first location is contaminated with depleted uranium; here, emulsion was added to the soil surface using a randomized block design using emulsion concentration and exposure time as variables. The second location is uncontaminated. Hydrological and ecological experiments are being performed on disturbed and undisturbed plots of different ages. The hydrologic experiments are focused on how infiltration and surface runoff potential might be impacted after the emulsion is applied to surface. Tests use tension infiltrometer and rainfall simulators for each plot, conducted quarterly. Ecological studies are focused on how the emulsion affects the germination rate and diversity of native seeds that have been exposed to the emulsion product.
Expected Results:
Soils contaminated with depleted uranium or other radionuclides are difficult to remediate, and thus pose a long-term potential risk to the environment and humans. The affected areas may be wide spread, covering areas many square miles or more and conventional remediation techniques are too costly. In addition, the extraction of these contaminates from the soil matrix by physical or chemical methods of separation may result in further spread of contamination. The proper application of the Encapco emulsion represents a potential cost-effective method for remediation of these contaminated sites. The results are expected to identify (1) the concentrations needed to effectively complex DU on soil surfaces, and how the effectiveness changes with exposure time; (2) whether the product alters the hydraulic characteristics of the soil and if that poses a potential risk for surface runoff and erosion; and (3) if widespread application of the product might impact ecosystem function by altering the germination of native seeds.
Below: Thirsty bees became a significant problem during hydrology tests in June of 2005.
Below: Tension infiltrometer measurements being taken on disturbed desert pavement surfaces.
Below: Julie Miller (DHS/SNSCthebestplacetowork) conducting surface runoff studies using a rainfall simulator.
Below: 30 squares, each 1.0 by 1.5 m in dimensions were used in the Site 1 study to evaluate complexation of DU with time and emulsion concentration. The tarps were used to reduce overspraying during application.
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