Pertechnetate ion [Tc(VII)O4-] reduction rate was determined in core samples from a shallow sandy aquifer located on the U.S. Atlantic Coastal Plain. The aquifer is generally low in dissolved O2 (4.3 were generally sufficient for complete reduction of Tc(VII) added [1-2.5 mmol (dry wt. sediment) g-1]. At these Fe(II) concentrations, the Tc (VII) reduction rate exceeded that observed previously for Fe(II)-mediated reduction on isolated solids of geologic or biogenic origin, suggesting that sediment Fe(II) was either more reactive and/or that electron shuttles played a role in sediment Tc(VII) reduction processes. In buried peats, Fe(II) in excess did not result in complete Tc(VII) reduction, perhaps because organic complexation of Tc(IV) limited formation of the Tc(IV) hydrous oxide. In some sands exhibiting Fe(II)/Tc(VII) concentrations
Revised: October 27, 2005 |
Published: July 1, 2004
Citation
Wildung R.E., S.W. Li, C.J. Murray, K.M. Krupka, Y. Xie, N.J. Hess, and E.E. Roden. 2004.Technetium Reduction in Sediments of a Shallow Aquifer Exhibiting Dissimilatory Iron Reduction Potential.FEMS Microbiology Ecology 49, no. 1:151-162.PNNL-SA-40807.