Microbes Limit Technetium Movement in Groundwater


A legacy of DOE’s former weapons production activities is the contamination of groundwater by radionuclides such as technetium (Tc). Tc-99 found in Hanford site groundwater is a mobile and long-lived fission product whose mobility can be retarded by subsurface minerals containing reduced or ferrous iron. Scientists from Pacific Northwest National Laboratory (PNNL) have now found that several species of microbes can increase the amount of reduced iron in the subsurface as part of their metabolic processes and that this additional reduced iron significantly reduces the mobility of Tc. Using a variety of instruments available at the Environmental Molecular Sciences Laboratory and the Advanced Photon Source, DOE scientific user facilities at PNNL and Argonne National Laboratory, respectively, the team found that Tc was 10 times less soluble when it came in contact with microbially generated reduced iron. This research provides a basis for a conceptual approach to limit the movement of Tc in groundwater at DOE site.


Plymale, A. E., J. K. Fredrickson, J. M. Zachara, A. C. Dohnalkova, S. M. Heald, D. A. Moore, D. W. Kennedy, M. J. Marshall, C. Wang, C. T. Resch, and P. Nachimuthu. 2011. Environmental Science and Technology 45, 951-7.