Isotopic evidence of trace metal sources and transport in eastern Canada as recorded from wet deposition
Bibliographic record
Abstract
Abundances of heavy metals and Pb and Sr isotope ratios have been determined in precipitation collected between December 1997 and June 1999 at St. Anicet and L'Assomption, near Montréal, Canada. Median enrichment factors for the heavy metals, relative to upper crustal abundances, are all »10 indicative of an anthropogenic origin. The 206 Pb/ 207 Pb values exhibit a large variation at both stations, with values of 1.170–1.190 and 1.130–1.150 recorded during the winter and summer seasons, respectively. The Pb isotope systematics defined by most of the samples from both stations may be explained by mixing of anthropogenic emissions from U.S. and Canadian sources. Comparison of Pb isotope ratios and heavy metal abundances between the same, individual precipitation events from both stations, however, do not systematically yield similar values and may be attributable to significant, local anthropogenic sources. The 87 Sr/ 86 Sr values for precipitations also exhibit a seasonal variation at both stations with the least radiogenic values being recorded, in general, during the winter months (<0.7085). These are possibly related to increased atmospheric emissions during the winter season from coal‐fired power plants located in North America. For the remaining months the 87 Sr/ 86 Sr values are either variable (0.7085–0.7100) at St. Anicet or constant (0.7085–0.7088) at L'Assomption. The latter possibly reflect Sr anthropogenic emissions from urban activity associated with Montreal.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 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) | 0.005 | 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".