Metal distribution in peat hummocks and hollows within 100 km of the copper smelter, Rouyn-Noranda, Quebec
Bibliographic record
Abstract
Profile samples were collected from peat hummocks and hollows from 37 peatlands within a 100 km radius of the Horne copper smelter, to investigate the value of peat as an historical record of smelter metal emissions. Splits of 630 samples were digested with HNO3-HClO4 prior to analysis for smelterrelated (Cu, Pb, Zn) and non-smelter (Ni) elements. Twenty-four samples were subjected to a four-step sequential extraction analysis to identify the main metal residence sites. Peat age was constrained from 137Cs, bulk density, and vertical growth rate data. Concentrations of Cu, Pb, and Zn were relatively low in the uppermost 20 cm of the hummocks and increased markedly between depths of 20 and 45 cm. In the tallest hummocks, metal concentrations decreased again below 50 cm depths and, by 60 to 75 cm depth, reached values less than those in the uppermost 20 cm. This pattern was most pronounced within 25 km of the smelter but was still discernible in hummocks at distances of more than 60 km. A similar pattern of increased and decreased concentrations was found in hollows, but it was compressed over the uppermost 20 cm of the hollow peat sequence. In hummocks 10 km and more from the smelter, about 25% of the Cu and 75% of the Pb and Zn resided in the labile phases, whereas closest to the smelter, in the 7 km hummock, even larger amounts of these elements were labile. In contrast to the smelter-derived elements, Ni concentration in hummocks and hollows varied.
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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) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| 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, 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".