Table 2.
Mӧssbauer Fe assignments in unspiked Bangladesh sediments. Fh = ferrihydrite, nGt = nano-goethite, and nano-Fe(III) = an unidentified, highly disordered nano-scale Fe(III) oxyhydroxide. Results are reported in both Fe concentrations (mg kg−1) and fractions (% of total Fe). Uncertainties are 2 standard deviations calculated from the Recoil™ Software. Details on 57Fe Mӧssbauer data collection and interpretation are given in Supplementary Material Section B.
| Site population | Concentration | Fraction | |
|---|---|---|---|
| Fe(III) in oxyhydroxides | Fh-like Fe(III) | 5370 ± 990 mg kg−1 | 27 ± 5% |
| nGt-like Fe(III) | 4180 ± 200 mg kg−1 | 21 ± 1% | |
| Nano-Fe(III) | 3780 ± 600 mg kg−1 | 19 ± 3% | |
| Fe(III) in clay and/or organic matter | 4580 ± 600 mg kg−1 | 23 ± 3% | |
| Fe(II) in clays and/or sorbed | 1790 ± 200 mg kg−1 | 9 ± 1% | |
| Fe(II) in ilmenite | 200 ± 200 mg kg−1 | 1 ± 1% | |