Intracellular Precipitation of Pb by <i>Shewanella putrefaciens</i> CN32 during the Reductive Dissolution of Pb-Jarosite
Bibliographic record
Abstract
Jarosites (MFe(3)(SO(4))(2)(OH)(6)) are precipitated in the Zn industry to remove impurities during the extraction process and contain metals such as Pb and Ag. Jarosite wastes are often confined to capped tailings ponds, thereby creating potential for anaerobic reductive dissolution by microbial populations. This study demonstrates the reductive dissolution of synthetic Pb-jarosite (PbFe(6)(SO(4))(4)(OH)(12)) by a subsurface dissimilatory Fe reducing bacterium (Shewanella putrefaciens CN32) using batch experiments under anaerobic circumneutral conditions. Solution chemistry, pH, Eh, and cell viability were monitored over time and illustrated the reduction of released structural Fe(III) from the Pb-jarosite to Fe(II). Inoculated samples containing Pb-jarosite also demonstrated decreased cellular viability coinciding with increased Pb concentrations. SEM images showed progressive nucleation of electron dense nanoparticles on the surface of bacteria, identified by TEM/EDS as intracellular crystalline precipitates enriched in Pb and P. The intracellular precipitation of Pb by S. putrefaciens CN32 observed in this study provides potential new insight into the biogeochemical cycling of Pb in reducing environments.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".