Phytochelatins Are Bioindicators of Atmospheric Metal Exposure via Direct Foliar Uptake in Trees near Sudbury, Ontario, Canada
Bibliographic record
Abstract
Plants produce phytochelatins in response to copper and nickel, the primary metal pollutants emitted by the dominant smelting operation in Sudbury. Copper and nickel concentrations in soils decline sharply with distance from this facility, primarily as a result of early smelting practices. Phytochelatin concentrations in Sudbury-area trees, however, do not correlate with metal levels in soils. Rather, phytochelatin production in tree leaves is driven by metals currently released to the atmosphere through the 381 m emissions stack. Phytochelatin concentrations in the foliage of three tree species growing in situ are highest 20-30 km from the stack, correlated with maximum acid-leachable concentrations of deposited copper and nickel. Similar results observed in potted trees placed adjacent to indigenous trees confirm that aerially deposited metals are the source of current metal stress patterns. The addition of peat moss "filters" to potted soils did not alter this response, indicating that direct foliar metal uptake is responsible.
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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 | 0.000 | 0.001 |
| Science and technology studies | 0.002 | 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) | 0.002 | 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".