Mobility of Source Zone Heavy Metals and Radionuclides

The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr

Project

Mobility of Source Zone Heavy Metals and Radionuclides: The Mixed Roles of Fermentative Activity on Fate and Transport of U and Cr

Funding

U.S. Department of Energy, Office of Biological and Environmental Research, Environmental Remediation Sciences Program

Collaborators

  • INL - Bill Apel, Brady Lee, Bill Smith
  • MSU - Robin Gerlach, Brent Peyton, Laureen Kelly, Erin Field

Description

Various U. S. Department of Energy (DOE) low and medium-level radioactive waste sites contain mixtures of heavy metals, radionuclides and assorted organic materials. Over time, water infiltrates the wastes, and releases metals and radionuclides causing transport into the surrounding environment.

We propose that fermentative microorganisms are active in these sites and may control metal and radionuclide migration from source zones. The following overarching hypothesis will drive our research:

Metals and radionuclides can be mobilized by infiltration of water into waste storage sites. Microbial communities of lignocellulose degrading and fermenting microorganisms present in the subsurface of contaminated DOE sites can significantly impact migration by directly reducing and immobilizing metals and radionuclides while degrading complex organic matter to low molecular weight organic compounds. These low molecular weight organic acids and alcohols can increase metal and radionuclide mobility by chelation(i.e., certain organic acids) or decrease mobility by stimulating respiratory metal reducing microorganisms.

We will test this hypothesis at multiple scales in three tasks examining

  1. Effect of fermentation on reactive transport of metals and radionuclides in geological media.
  2. Community response to carbon and electron flow in waste environments.
  3. Influence of spatial and temporal variables on metal and radionuclide migration.

This work will provide observations and quantitative data integrated across multiple scales to identify and predict the coupled effects of fermentative carbon and electron flow on the transport of radionuclides and metals in the subsurface; a primary concern of the DOE Environmental Remediation Science Division (ERSD).

Project Links

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  1. Historical Description of RWMC Surrogate Buried Waste Test Pits

  2. Final Work Plan for Organic Contamination in the Vadose Zone (OCVZ) Operable Unit (OU) 7-08 Focused Remedial Investigation Feasibility Study (RI/FS) Report (NOTE: See Section 2 pages 55-66 (2-54 to 2-65))
  3. Thickness of Surficial Sediment at and near the Idaho National Engineering Laboratory, Idaho, U.S. Geological Survey Open-File Report 96 330.