Suspensions from a gut simulator were spiked with inorganic germanium, arsenic, selenium, tin, antimony, tellurium, mercury, lead, and bismuth and the headspace was analysed by gas chromatography with inductively coupled plasma mass spectrometry. The largest printed production rates relative to the spike were for tellurium, then arsenic, then selenium. Volatile antimony and bismuth from the salt spikes were only trace and did not increase with the amount added. Incubation with a reference soil changed the pattern and raised the printed antimony conversion rate.
Key numbers
Figures below are copied as printed. Units are not converted. Species are not merged.
| Analyte | What was reported | Value | Unit | Basis | Where |
|---|---|---|---|---|---|
| Se | maximal hourly production rates relative to the amount spiked; 0.6, 2, and 9 ng/mg/h, respectively (Se, As, and Te) | 0.6 | ng/mg/h | hourly production relative to the amount spiked; element mass | Abstract, p. 1 |
| As | 2 ng/mg/h for As | 2 | ng/mg/h | hourly production relative to the amount spiked; element mass | Abstract, p. 1 |
| Te | 9 ng/mg/h for Te | 9 | ng/mg/h | hourly production relative to the amount spiked; element mass | Abstract, p. 1 |
| Sb | metal(loid) background concentration of the SHIME suspension (both 40 µg/L) | 40 | µg/L | suspension concentration | Results, element concentration, p. 4 |
| Bi | both 40 µg/L | 40 | µg/L | suspension concentration | Results, element concentration, p. 4 |
| Se | 60 µg Se/L or 0.6 µg Se absolute per batch | 60 | µg/L | suspension concentration | Results, p. 4 |
| Se | 0.6 µg Se absolute per batch | 0.6 | µg | absolute element mass per batch | Results, p. 4 |
| Sb | (CH3)3Sb (88.5%) | 88.5% | percent recovery | standard addition recovery | Figure S1, stated in text, p. 4 |
| Sb | specific conversion rates for Sb, Bi, Se, and Te were 5, 6, 12, and 64 ng/(mg h), respectively | 5 | ng/(mg h) | specific conversion rate, element mass | Dependence on matrix; Table S8 cited, p. 5 |
| Bi | 6 ng/(mg h) for Bi | 6 | ng/(mg h) | specific conversion rate, element mass | Dependence on matrix, p. 5 |
| Se | 12 ng/(mg h) for Se | 12 | ng/(mg h) | specific conversion rate, element mass | Dependence on matrix, p. 5 |
| Te | 64 ng/(mg h) for Te | 64 | ng/(mg h) | specific conversion rate, element mass | Dependence on matrix, p. 5 |
| As | higher volatilization of As (five times more) and Se (three times more) compared to the 5 µg multielement batches | five times more | fold versus the 5 µg multielement batch | relative volatilization | Figure 2 discussion, p. 4 |
| Se | Se (three times more) | three times more | fold versus the 5 µg multielement batch | relative volatilization | Figure 2 discussion, p. 4 |
The structured evidence record for this source holds 17 copied values. The table above is the short set.
Methods (brief)
Ten millilitre aliquots were incubated anaerobically at 37 degrees C for 90 hours, generally in triplicate. Multielement spikes followed Table 3, with mercury(II) and antimony(III) used at one-tenth of the stated concentration. Headspace was purged with helium, cryotrapped, and analysed by GC-ICP-MS. Sterile autoclaved controls produced only trace volatile species.
Evidence fitness
In vitro volatilization of arsenic, selenium, and tellurium by intestinal microbiota, with only trace volatile antimony and bismuth that the authors attribute to background in the suspension rather than to the added salts. A soil-matrix incubation produced higher specific conversion rates, including for antimony.
It does not report concentrations of these elements in drinking water, food, wipes, toys, or jewelry. Species-resolved amounts in the headspace are in supporting tables that are not in this main-text extract, so those table values are not copied. It does not identify a gene for antimony methylation.
Limitations
The main text gives rates and fold changes, not the full species-amount tables (those are Supporting Information). Antimony and bismuth from inorganic spikes are described as trace and independent of dose, so a dose-response concentration is not available. One fecal donor was used. The soil result uses a reference soil rather than a consumer product. Mixed sulfur species were identified, but their toxicology is stated as unknown.
Related evidence
Update history
No substantive edit history is available in this build. The full commit record is available in git.