Investigation of the Potential for 90Sr Immobilization in INTEC Perched Water via Microbially Facilitated Calcite Precipitation

Technical Report · Sun Oct 01 04:00:00 EDT 2006

DOI:https://doi.org/10.2172/911864· OSTI ID:911864

Fujita, Yoshiko; Wright, Karen E; Smith, William A

The goal of this work is to evaluate the applicability of a biogeochemical sequestration approach for remediation of 90Sr contamination in perched water zones underlying the Idaho Nuclear Technology and Engineering Center (INTEC). The approach is based on the accelerated co-precipitation of the contaminant in calcite, where the acceleration is catalyzed by the microbial urea hydrolysis. We have previously demonstrated the potential for this remediation mechanism to immobilize strontium. Urea hydrolysis promotes calcite precipitation (and trace metal co-precipitation) by increasing groundwater pH and alkalinity. Ureolysis is catalyzed by the urease enzyme, which is produced by many environmental microorganisms. In the Snake River Plain Aquifer, which is saturated with respect to calcite, any co-precipitated 90Sr should be effectively sequestered over the long-term, even after return to pre-manipulation conditions. Another advantage of the ureolysis approach is that the NH4+ ions produced by the reaction can exchange with cations sorbed to subsurface minerals, thereby enhancing the availability of the radionuclides for re-capture via a more stable mechanism (co-precipitation rather than adsorption).

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 911864
• Report Number(s): INL/EXT-06-11896
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
ACCELERATION
ACID NEUTRALIZING CAPACITY
ADSORPTION
AVAILABILITY
CALCITE
CATIONS
CONTAMINATION
HYDROLYSIS
MICROORGANISMS
PRECIPITATION
RADIOISOTOPES
SNAKE RIVER PLAIN
STRONTIUM
UREA
UREASE
WATER
calcite precipitation
microbial urea hydrolysis
sequestration