Technetium reduction in sediments of a shallow aquifer exhibiting dissimilatory iron reduction potential

摘要: Pertechnetate ion [Tc(VII)O4−] reduction rate was determined in core samples from a shallow sandy aquifer located on the US Atlantic Coastal Plain. The is generally low dissolved O2 ( 4.3 were sufficient for complete of Tc(VII) added [1–2.5 μmol (dry wt. sediment) g−1]. At these Fe(II) concentrations, Tc (VII) exceeded that observed previously Fe(II)-mediated isolated solids geologic or biogenic origin, suggesting sediment either more reactive and/or electron shuttles played role processes. In buried peats, excess did not result removal solution, perhaps because organic complexation Tc(IV) limited formation hydrous oxide. some sands exhibiting Fe(II)/Tc(VII) concentrations <1.1, there presumptive evidence direct enzymatic Tc(VII). Addition donors (acetate, lactate) resulted microbial (up to 35%) Fe(III) and corresponding increases extractable exhibited lowest initial highest hydraulic conductivities, accelerated could offer viable means attenuating mobile this type system.