Distinction des accumulations de métaux provenant de sources géogènes et anthropiques aux environs de la fonderie Horne : la dendrogéochimie en tant qu'outil de surveillance environnementale
Bibliographic record
Abstract
One of the main challenges in environmental research in Canada is to distinguish between natural and anthropogenic accumulations of potentially toxic metals in mining regions. In this paper, we evaluate a new environmental monitoring tool that combines dendrochronology with natural (Ca, Mg, Ca/Mn, delta-2H, delta-13C) and anthropogenic (Cd, Pb, 206Pb/207Pb) geochemical tracers. Spruce trees and soil horizons were sampled at a control site in the Hudson Bay region and near the Horne smelter, which has been in operation in Rouyn-Noranda, Quebec, since 1928. The delta-2H and delta-13C values from trees near the smelter show major changes immediately after 1928. These changes are due to the presence of atmospheric SO2 that generates a rapid response in the foliar system. Cadmium and lead concentrations show a major increase starting in 1944 that coincides with a decrease in the 206Pb/207Pb ratios. Smelter activities likely caused these changes and the 14-year delay in response may be due mainly to the buffering effect of soils. The 206Pb/207Pb ratios indicate that growth rings contain at least three categories of lead, i.e. natural lead derived from the mineral soil horizons, industrial lead from Canadian and American urban areas, and mining lead typical of the Abitibi sulphides emitted by the smelter. This new use of natural and anthropogenic tracers allows us to recognize the succession of atmospheric and pedogeochemical transformations related to industrial activities in a mining area.
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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 | 0.002 | 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) | 0.000 | 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".