Pb-Bearing Ferrihydrite Bioreduction and Secondary-Mineral Precipitation during Fe Redox Cycling

The significant accumulation of Pb from anthropogenic activities threatens environmental ecosystems. In the environment, iron oxides are one main carriers Pb. Thus, redox cycling oxides, which is due to biotic and abiotic pathways, leads their dissolution or transformation, controls fate However, a knowledge gap exists on bioreduction in Pb-bearing ferrihydrites, secondary-mineral precipitation, partitioning during bioreduction/oxidation/bioreduction cycle. this study, ferrihydrite (Fh_Pb) with various Pb/(Fe+Pb) molar ratios (i.e., 0, 2, 5%) were incubated iron-reducing bacterium Shewanella oneidensis MR-1 for 7 days, oxidized days (atmospheric O2), bioreduced second time days. doping led drop rate extent reduction. Lepidocrocite (23–56%) goethite (44–77%) formed first reduction period. Magnetite (72–84%) extremely-low-dissolved bioavailable concentrations measured cycles, indicates that significantly sorbed onto minerals formed. Overall, study highlights influence as well nature secondary