Concentrations of Chlorinated Organic Compounds in Various Receiving Environment Compartments Following Implementation of Technological Changes at a Pulp Mill
Bibliographic record
Abstract
Concentrations of chlorinated organics in the Wapiti/Smoky River system downstream of the Grande Prairie, Alberta kraft pulp mill have declined in all measured compartments. Since 1992, the mill has converted the bleaching process to chlorine dioxide delignification (100% ClO2 substitution), implemented condensate stripping, upgraded the aerated stabilization basins, and improved effluent monitoring and management. Since these changes, monthly average final mill effluent parameters have been 0.5 kg ADMT−1 AOX and <0.1 μg L−1 of tri-, tetra- and pentachlorinated phenol compounds. Concentrations of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 2,3,7,8-tetrachlorodibenzofuran (TCDF) are now below detection limits of 1.0–5.0 pg L−1. Environmental concentrations have shown a concomitant decrease, which has been rapid in water and sediments. TCDD/TCDF is not detectable in water and is at or near the detection limit in suspended sediments (at both near and far-field sites). Concentrations of TCDD/TCDF have also declined in fish, although at a slower pace which indicates a biological half-life of over 6 months for mountain whitefish (Prosopium williamsoni) fillets and >1 yr for burbot (Lota lota) livers. Chlorinated phenolic concentrations have paralleled the trends seen for dioxins and furans, with a rapid decrease to non-detectable concentrations in water and concentrations in the very low μg L−1 range (for up to 4 compounds only) in suspended sediments. These compounds were rarely detectable in fish fillets even before the mill changes. Extractable organic chlorine (EOCl) was not detectable in water and was generally in the <0.5–2 mg L−1 range on suspended sediments. EOCl in fish fillets has declined from 13 to 43 mg L−1 before the mill changes to 1–2 mg L−1 in September 1993. EOCl in fish bile was not detectable in the current survey.
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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) | 0.001 | 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) | 0.006 | 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".