Thallium element
Thallium (Tl) is an element. Its neutral-atom identifier does not denote dissolved Tl(I), a thallium mineral or a secondary resource. The curated laboratory study concerns release of aqueous thallium from a synthetic, nonideal Tl(I)-bearing jarosite during bacterial ferric-iron reduction. No criticality designation or industrial recovery is inferred.
Identifiers & Classification
| System | Identifier | Label |
|---|---|---|
| CHEBI |
CHEBI:30440
|
thallium atom |
Microbial & Biochemical Mechanisms (1)
Thallium mobilization accompanying CN32-associated jarosite reduction
redox transformation
Microbial
Associated Organisms:
Shewanella putrefaciens CN-32 (NCBITaxon:319224)
Washed living CN32 cells were associated with ferrous-iron production and greater aqueous thallium release from synthetic Tl-bearing jarosite than cell-free and autoclaved-cell mineral controls. The reduced element demonstrated by the ferrozine assay is iron; direct thallium reduction is not established. Substantial thallium also dissolved abiotically. This supports a laboratory mobilization process, not thallium immobilization or isolated-product recovery.
Experimental Context & Analytical Limits:
Synthetic nonideal Tl-jarosite, 0.0561 +/- 0.0097 g per tube, was exposed to 15 mL modified M1 medium in 20 mL tubes at 28 degrees C with 20 rpm end-over-end rotation in a 95% nitrogen/5% hydrogen anaerobic chamber. Medium contained 24 mM sodium lactate and 20 mM PIPES, initially pH 7.3, without added phosphate. Cells were grown aerobically at 32 degrees C, washed and divided into viable and autoclaved preparations; the reported 1.65 g wet cells per 2 L is not dry biomass. Mineral-containing tubes were sampled destructively in triplicate through nominal 893 hours; mineral-free live and cell-free controls were sampled in duplicate. Replicate tubes share prepared inoculum and do not establish independent culture-batch replication. Thallium was measured by ICP-OES after 0.2 micrometre filtration; this is a filtered elemental concentration, not a recovered product or a direct oxidation-state measurement.
Synthetic nonideal Tl-jarosite, 0.0561 +/- 0.0097 g per tube, was exposed to 15 mL modified M1 medium in 20 mL tubes at 28 degrees C with 20 rpm end-over-end rotation in a 95% nitrogen/5% hydrogen anaerobic chamber. Medium contained 24 mM sodium lactate and 20 mM PIPES, initially pH 7.3, without added phosphate. Cells were grown aerobically at 32 degrees C, washed and divided into viable and autoclaved preparations; the reported 1.65 g wet cells per 2 L is not dry biomass. Mineral-containing tubes were sampled destructively in triplicate through nominal 893 hours; mineral-free live and cell-free controls were sampled in duplicate. Replicate tubes share prepared inoculum and do not establish independent culture-batch replication. Thallium was measured by ICP-OES after 0.2 micrometre filtration; this is a filtered elemental concentration, not a recovered product or a direct oxidation-state measurement.
Curated Evidence Points:
Support
Source:
smeaton2012_chapter4
Chapter 4 methods/results and Figure 4.1 show approximately 4.6 mM filtered Fe(II) and 3.2 mM filtered Tl in living-cell mineral tubes by the nominal 893-hour endpoint, versus approximately 2.1 mM Tl in cell-free mineral controls. Autoclaved-cell tubes release less Tl and show negligible Fe(II), as do cell-free Fe(II) controls. These are concentrations from this synthetic feed, not extraction yields. Different pH trajectories and possible dead-cell surface effects preclude attributing the entire between-arm difference to a single direct electron-transfer pathway.
Partial
Source:
smeaton2012_si
SI S1-S2, Table S2 and Figures S3-S6 constrain substrate and product interpretation. The main account gives (H3O)0.29Tl0.71Fe2.74(SO4)2(OH)5.22(H2O)0.78, whereas SI S1 prints (OH)6; this discrepancy is retained rather than assigning a pure mineral endmember. PIPES sulfur prevents independent tracking of sulfate release. Table S2 includes stoichiometrically estimated acetate, bicarbonate and sulfate despite its measured-concentrations heading. Secondary saturation indices are model predictions. Local Tl/S/O enrichment in Figure S5 does not identify a pure sulfate phase or quantify a recovered fraction; its caption incorrectly names O and Fe. Fe/O-rich particles likewise lack phase-specific identification.
Partial
Source:
smeaton2012_chapter4
The separate 72-hour mineral-free sorption experiment used about 35 micromolar Tl in 0.1 M NaCl with live cells, autoclaved cells and cell-free controls near nominal pH 5 and 6.2/6.3. The authors report no significant between-arm Tl depletion difference. This limited null result does not establish absence of sorption at the millimolar concentrations of the dissolution assay or in other environmental systems. Methods, results and supporting table labels disagree on pH; final pH is not identical across arms. No statistically stronger conclusion is inferred from the printed data.
Partial
Source:
smeaton2012_si
Table S1 contains mismatched pH labels and a contradictory significance notation. Reported biomass-to-cell-count conversions also differ within the source. ATP luminescence is a biomass/viability proxy, not a direct viable-cell count; some prose time/value assignments disagree with Figure 4.1. Proposed ATPase uptake/efflux and specific detoxification mechanisms were not tested by expression or perturbation experiments. The source also uses 853/863 hours in passages alongside the nominal 893-hour assay; no silent harmonization or industrial performance claim is made.
Sources & References
-
chebi_thallium: ChEBI:30440, thallium atom. Current official API verifies the neutral Tl atom and zero charge.
https://www.ebi.ac.uk/chebi/CHEBI:30440 (accessed 2026-10-15) -
smeaton2012: Smeaton CM, Walshe GE, Fryer BJ and Weisener CG (2012). Reductive Dissolution of Tl(I)-Jarosite by Shewanella putrefaciens: Providing New Insights into Tl Biogeochemistry. Environmental Science & Technology 46:11086-11094. Bibliographic identity and abstract verified; final journal PDF was not acquired.
https://doi.org/10.1021/es302292d (accessed 2026-10-15) -
smeaton2012_chapter4: Smeaton CM (2012), University of Windsor PhD dissertation, Investigating the Susceptibility of Jarosite Minerals to Reductive Dissolution by a Dissimilatory Metal Reducing Bacterium (Shewanella putrefaciens CN32). Chapter 4, printed pages 113-148 (PDF 138-173), main text, Figures 4.1-4.3, Tables S4.1-S4.4 and Figures S4.1-S4.7. Author primary account of the same experiment, not independent replication.
https://www.collectionscanada.gc.ca/obj/thesescanada/vol2/002/NR78584.PDF (accessed 2026-10-15) -
smeaton2012_si: Original ACS supporting information for DOI 10.1021/es302292d, 13-page PDF, sections S1-S4, Tables S1-S4 and Figures S1-S6. Official DOI-matched ACS Figshare article 2477893, file 4120573.
https://doi.org/10.1021/es302292d.s001 (accessed 2026-10-15) -
ncbi_cn32: NCBI Taxonomy 319224: Shewanella putrefaciens CN-32, strain rank, parent species 24. Current official XML checked; experiment calls this CN32 (ATCC BAA-453).
https://www.ncbi.nlm.nih.gov/datasets/taxonomy/319224/ (accessed 2026-10-15)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-15T10:31:23.406244+00:00 |
codex (GPT-6; codex) | CREATE | Added the thallium element with qualified CN32-associated mobilization from synthetic Tl-jarosite; preserved abiotic release, separate sorption null, source/version conflicts and lack of recovery or direct Tl-redox evidence. |
Record source: data/records/thallium.yaml