Study of coliform bacteria in Canadian pulp and paper mill water systems : their ecology and utility as health hazard indicators
Bibliographic record
Abstract
Coliform bacteria have long been used to indicate fecal contamination of food, water, and solid surfaces, and thus the presence of a health hazard. In this study, the in-mill water and external effluent treatment systems of seven typical Canadian pulp and paper mills were shown to support the growth of numerous coliforms, especially Klebsiella spp, Escherichia coli, Enterobacter spp., and Citrobacter spp . Mill coliforms were shown to be not just simple transients from feedwater or furnish (wood), but to be continuously growing, especially in the primary clarifiers. Therefore, coliforms and fecal coliforms cannot be used as fecal contamination indicators in pulp and paper mill water and effluent treatment systems. N2-fixing coliform populations were detected in mill water systems and were analyzed using N2-fixation assays and nitrogenase gene (nifH) probing. Both active in situ populations and cultured microbial isolates were tested. Active N2-fixation was demonstrated in six primary clarifiers. Measurement of the numbers and composition of the total culturable bacterial community in a primary clarifier revealed that approximately 50% of all aerobic cells contained nifH , of which >90% were Klebsiella. Coliforms growing on MacConkey agar plates from the primary clarifier were all identified as Klebsiella and 100% of these Klebsiella contained the nifH gene. Preliminary estimates indicate that the amount of N2 fixed per day is substantial in some clarifiers.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: yes | Observational | medium |
| gpt | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: yes | Observational | high |
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 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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, unvalidatedLabeled directly by 2 models reading the full record.
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".