Derek R. Lovley E. E. Roden 1993 <p><span>The potential utility of&nbsp;</span>⁵⁵<span>Fe as a tracer for Fe(III) reduction in aquatic sediments was evaluated using freshwater sediments from the Potomac River, Md, in which Fe(III) reduction was the predominant terminal electron accepting process. In laboratory incubations of sediments amended with poorly crystalline&nbsp;</span>⁵⁵<span>Fe(III) oxide, the accumulation of&nbsp;</span>⁵⁵<span>Fe in Fe(II) over time paralleled Fe(II) production. However, within 1 h of addition of&nbsp;</span>⁵⁵<span>Fe(III) oxide, significant quantities of&nbsp;</span>⁵⁵<span>Fe were recovered in extractable (1 M sodium acetate, pH 5) and soluble Fe(II) pools. There was proportionately more&nbsp;</span>⁵⁵<span>Fe(II) activity in sediments with higher Fe(II) concentrations. These results suggest that there was rapid isotopic exchange between&nbsp;</span>⁵⁵<span>Fe in poorly crystalline Fe(III) oxide and the Fe(II) pools. Because of this exchange,&nbsp;</span>⁵⁵<span>Fe could not be used to trace Fe(III) reduction in sediments in the manner that&nbsp;</span>³⁵<span>SO</span>₄<span>&nbsp;</span>²⁻<span>&nbsp;is used to trace sulfate reduction. Although accumulation of&nbsp;</span>⁵⁵<span>Fe in Fe(II) pools paralleled unla‐beled Fe(II) production, given the relative ease with which Fe(II) pools in sediments can be measured there is no apparent advantage to using&nbsp;</span>⁵⁵<span>Fe to follow Fe(III) reduction.</span></p> application/pdf 10.1080/01490459309377931 en Taylor & Francis Evaluation of 55Fe as a tracer of Fe(III) reduction in aquatic sediments article