Tin element Critical Material
The element Sn, distinct from organotin compounds, dissolved inorganic tin, tin minerals, indium tin oxide and tin-bearing waste resources. The United States 2025 list's Tin designation is mapped to this element; it does not automatically designate tributyltin or contaminated sediment as critical. The curated microbial experiment concerns organotin ligand transformation, not destruction of the tin element or production of metallic tin.
Identifiers & Classification
| System | Identifier | Label |
|---|---|---|
| CHEBI |
CHEBI:27007
|
tin atom |
Criticality Designations
| Jurisdiction | List Name | Edition / Document | Classification | Source |
|---|---|---|---|---|
| United States | Department of the Interior Final List of Critical Minerals | 2025 final list, published 7 November 2025 | critical |
us_2025
|
Microbial & Biochemical Mechanisms (1)
C22-inoculated sediment microcosm organotin debutylation
other
Microbial
Sediment microcosms inoculated with living bacterial isolate C22 showed declining tributyltin (TBT) and appearance of dibutyltin (DBT) and monobutyltin (MBT) analytical signals. This supports culture-associated loss of butyl groups from organotin, with partial transformation and residual TBT. The experiment does not measure a change in tin oxidation state, complete mineralization, isolated tin recovery or detoxification in a biological toxicity assay.
Experimental Context & Analytical Limits:
C22 was isolated from Cork Harbour sediment; species identity is unresolved here. Laboratory Courtown Beach sediment was autoclaved at 121 degrees C for 40 min, sieved to 1 mm, spiked with tributyltin chloride in methanol at a nominal 100 ng/g, air-dried for one week and mixed twice daily. Each sealed microcosm held 200 g sediment and a 2 cm water column; the inoculated arm received 10 mL overnight culture in nutrient broth. Triplicate microcosms, including an uninoculated control condition, were incubated in darkness at room temperature. Exact temperature, culture cell density, sediment pH, salinity and water composition were not reported. Samples were taken on days 0, 30, 60, 90 and 120. Methods describe taking 5 g from each replicate to a 15 g total, followed by 1 g analytical subsamples. This appears to pool the biological replicates; the repeated analytical assays therefore do not establish independent biological replication of the reported means.
C22 was isolated from Cork Harbour sediment; species identity is unresolved here. Laboratory Courtown Beach sediment was autoclaved at 121 degrees C for 40 min, sieved to 1 mm, spiked with tributyltin chloride in methanol at a nominal 100 ng/g, air-dried for one week and mixed twice daily. Each sealed microcosm held 200 g sediment and a 2 cm water column; the inoculated arm received 10 mL overnight culture in nutrient broth. Triplicate microcosms, including an uninoculated control condition, were incubated in darkness at room temperature. Exact temperature, culture cell density, sediment pH, salinity and water composition were not reported. Samples were taken on days 0, 30, 60, 90 and 120. Methods describe taking 5 g from each replicate to a 15 g total, followed by 1 g analytical subsamples. This appears to pool the biological replicates; the repeated analytical assays therefore do not establish independent biological replication of the reported means.
Curated Evidence Points:
Support
Source:
finnegan_2018
Figure 3's C22 panel shows a sustained lower TBT signal than the nearly stable uninoculated control, with DBT and MBT appearing. Figure 4 independently displays the C22 time-course chromatograms. Sections 2.1 and 3.4-3.5 describe retention-time and selected-ion identification after sodium-tetraethylborate derivatization, followed by static-headspace GC-MS. The ethylated structures labelled in Figure 4 are analytical derivatives, not additional environmental products. No gene or enzyme was tested, and no viable-cell or sterility time course was provided.
Partial
Source:
finnegan_2018
Section 2.4 reports day-120 C22 values of 52.73, 28.5 and 13.8 ng/g wet sediment for TBT, DBT and MBT, respectively. These are the authors' compound-specific results, not elemental tin mass balance or metal yield. Section 2.3.1 reports linear calibration ranges only up to 50 ng/g. Separately, Section 2.3.2 reports sediment spike-recovery accuracy testing over 5-60 ng/g wet weight (n=3), with 94-103% recovery and relative standard deviations below 10% across the tested organotins. This is analytical recovery, not microbial extraction yield. Dilution or extension of the linear calibration above 50 ng/g is not described; the recovery tests do not extend to the nominal 100 ng/g starting spike. Exact TBT percentages therefore remain quantitatively uncertain. Figure 3 also shows C22 MBT declining from day 90 to day 120, without measuring its further products. Complete degradation cannot be inferred.
Partial
Source:
finnegan_2018
The uninoculated comparator is useful, but Methods do not specify a matched sterile nutrient-broth addition or a killed-cell arm. Sediment adsorption, extraction efficiency, inoculum chemistry and biological transformation are not completely separated. Method validation uses spiked sediment; certified reference material validation is proposed rather than performed. The source's general removal and toxicity language does not establish a purified product, biological safety endpoint or field deployment.
Context_only
Source:
genbank_c22
The authority record explicitly links KX881904.1 to strain C22 but identifies the organism only as bacterium. The paper's Enterobacteriales wording does not establish a genus or species. No species-level or strain-specific taxonomy identifier is asserted, and the sequence does not itself demonstrate activity.
Sources & References
-
chebi_tin: ChEBI:27007 - tin atom; formula Sn and net charge 0
https://www.ebi.ac.uk/chebi/CHEBI:27007 (accessed 2026-10-11) -
us_2025: US Department of the Interior, Geological Survey. Final 2025 List of Critical Minerals, 7 November 2025, Federal Register 90:50494-50497, document 2025-19813; Tin row on page 50497.
https://www.govinfo.gov/content/pkg/FR-2025-11-07/html/2025-19813.htm (accessed 2026-10-11) -
finnegan_2018: Finnegan et al. (2018). Microbes a Tool for the Remediation of Organotin Pollution Determined by Static Headspace Gas Chromatography-Mass Spectrometry. Molecules 23:627. DOI 10.3390/molecules23030627; PMC6017036. Sections 2.1, 2.3-2.4, 3.1-3.6 and Figures 3-4.
https://doi.org/10.3390/molecules23030627 (accessed 2026-10-11) -
genbank_c22: GenBank KX881904.1 - Bacterium strain C22 16S ribosomal RNA gene, partial sequence; source organism is bacterium, strain qualifier C22. This sequence record does not resolve a species identity.
https://www.ncbi.nlm.nih.gov/nuccore/KX881904.1 (accessed 2026-10-11)
Curation History
| Timestamp | Curator | Action | Summary |
|---|---|---|---|
2026-10-11T06:52:09Z |
Codex (GPT-6; Codex) | CREATE | Created tin identity and dated US criticality with C22 organotin transformation evidence, retaining unresolved taxonomy, analytical calibration and control limits, and separating debutylation from tin redox, mineralization, detoxification and recovered-metal yield. |
2026-10-11T07:01:08.100051Z |
Codex (GPT-6; Codex) | edit_record | Addressed issue 40 by separating linear calibration through 50 ng/g from sediment spike-recovery accuracy at 5-60 ng/g; preserved narrower dilution/calibration-extension uncertainty and analytical-versus-biological recovery distinctions after rereading primary Sections 2.3.1-2.3.2. |
Record source: data/records/tin.yaml