Environ. Sci. Technol. 2011, 45, 951–957
Competitive Reduction of Pertechnetate (99TcO4-) by Dissimilatory Metal Reducing Bacteria and Biogenic Fe(II) ANDREW E. PLYMALE,† J A M E S K . F R E D R I C K S O N , * ,† JOHN M. ZACHARA,† ALICE C. DOHNALKOVA,† STEVE M. HEALD,‡ DEAN A. MOORE,† DAVID W. KENNEDY,† MATTHEW J. MARSHALL,† CHONGMIN WANG,† CHARLES T. RESCH,† AND PONNUSAMY NACHIMUTHU† Pacific Northwest National Laboratory, P.O. Box 999, Richland, Washington 99352, United States, and Argonne National Laboratory, Argonne, Illinois 60439, United States
Received August 12, 2010. Revised manuscript received November 16, 2010. Accepted December 3, 2010.
The fate of pertechnetate (99Tc(VII)O4-) during bioreduction was investigated in the presence of 2-line ferrihydrite (Fh) and various dissimilatory metal reducing bacteria (DMRB) (Geobacter, Anaeromyxobacter, Shewanella) in comparison with TcO4- bioreduction in the absence of Fh. In the presence of Fh, Tc was present primarily as a fine-grained Tc(IV)/Fe precipitate that was distinct from the Tc(IV)O2 · nH2O solids produced by direct biological Tc(VII) reduction. Aqueous Tc concentrations (
