@TechReport{Lee_ORNL-TM-12401_19930801,
 author         = {S. Y. Lee and Mark Elless and Forrest M. Hoffman},
 title          = {Solubility Measurement of {U}ranium in {U}ranium-Contaminated Soils},
 type           = {Technical Memorandum},
 number         = {ORNL/TM-12401},
 institution    = {Oak Ridge National Laboratory},
 address	= {Oak Ridge, Tennessee, USA},
 day		= 1,
 month          = aug,
 year           = 1993,
 abstract	= {A short-term equilibration study involving two uranium-contaminated soils at the Department of Energy’s Fernald Environmental Management Program (FEMP) site was conducted as part of the In Situ Remediation Integrated Program. The goal of this study is to predict the behavior of uranium during on-site remediation of these soils. Geochemical modeling was performed on the aqueous species dissolved from these soils following the equilibration study to predict the on-site uranium leaching and transport processes. Results showed that the soluble levels of the major components (total uranium, calcium, magnesium, and carbonate) increased continually for the first four weeks. After the first four weeks, these components either reached a steady-state equilibrium (in those components having solubilities approaching that of the controlling solid phase for that component) or continued linearity throughout the study (in those components having low solubilities). Other major components, such as aluminum, potassium, and iron, reached a steady-state concentration within three days. Silica levels approximated the predicted solubility of quartz throughout the study. A much higher level of dissolved uranium was observed in the soil contaminated from spillage of uranium-laden solvents and process effluents than in the soil contaminated from settling of airborne uranium particles ejected from the nearby incinerator. The high levels observed for soluble calcium, magnesium, and bicarbonate are probably the result of magnesium and/or calcium carbonate minerals dissolving in these soils.  The increase in the total uranium levels with increasing carbonate levels is due to the complexation of uranium with carbonate species. Geochemical modeling confirms that the uranyl-carbonate complexes are the most stable and dominant in these solutions. The implication of this work is that the use of carbonate minerals on these soils for erosion control and road construction activities contributes to the leaching of uranium from contaminated soil particles.  Dissolved carbonates promote uranium solubility, forming highly mobile anionic species. Mobile uranium species are contaminating the groundwater underlying these soils. Therefore, the development of a site-specific remediation technology is urgently needed for the FEMP site.}
}