Isomerization of chlortetracycline in prairie wetland water
Bibliographic record
Abstract
Abstract Chlortetracycline (CTC), an antimicrobial administered as a feed additive to cattle, swine, and poultry, is present in the corresponding manure. Land application of raw or processed (composted or stockpiled) manure provides a mechanism by which CTC (and other antimicrobials) enters the environment and becomes available for transport to surface receiving waters via rainfall or snowmelt runoff. Chlortetracycline has been detected in Canadian surface waters, but little has been reported on its fate in aquatic ecosystems. To address this knowledge gap, the dissipation of CTC‐enol was monitored in deionized water and water typical of wetlands within the prairie region of Canada. In deionized water, CTC‐enol tautomerized to CTC‐keto, and both tautomers epimerized to 4‐epi‐CTC‐enol and 4‐epi‐CTC‐keto, respectively. Irreversible isomerization to iso ‐CTC occurred, which then epimerized to 4‐epi‐ iso ‐CTC. In wetland water, although tauterization of CTC‐enol to CTC‐keto occurred, there was no evidence of the formation of the 4‐epimers of either CTC‐enol or CTC‐keto. The major product formed in the wetland water was iso ‐CTC, some of which epimerized to 4‐epi‐ iso ‐CTC. Although CTC‐enol was shown to tautomerize to CTC‐keto, the concentration of CTC‐keto remained low in both deionized and wetland water, suggesting that the isomerization of CTC‐enol to iso ‐CTC most likely occurred via CTC‐keto. The dissipation of CTC‐enol in wetland water was described by pseudo first‐order kinetics with a DT 50 (time required for 50% dissipation) value of 4.8 h. The short DT 50 value of CTC and reduced antimicrobial activity of iso ‐CTC and 4‐epi‐ iso ‐CTC suggest a lower probability for selection for CTC‐resistant bacteria in Canadian Prairie aquatic ecosystems.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 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) | 0.003 | 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 teacher head, 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".