Orographic Cold-Trapping of Persistent Organic Pollutants by Vegetation in Mountains of Western Canada
Bibliographic record
Abstract
Conifer needles from mountain areas of Alberta and British Columbia, Canada, were collected from sites that ranged in altitude from 770 to 2200 masl and were analyzed for polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCs) to determine if they are progressively concentrated in colder, more elevated mountain areas, where temperatures decrease as elevation increases. Concentrations of OCs in needles ranged from 43 to 2430 pg g(-1), 55-17500 pg g(-1), and 11-2930 pg g(-1) (dry weight), for total hexachlorocyclohexanes (HCHs), PCBs, and endosulfans, respectively. The more volatile OCs, with subcooled liquid vapor pressures (PL) > 0.1 Pa at 25 degrees C, increased at higher altitudes, whereas the less volatile OCs were either unrelated or inversely correlated with altitude. These spatial patterns were similar for species of spruce (Picea engelmannii and glauca) and pine (Pinus contorta and albicaulis). Back trajectories revealed that air masses arriving at these sites traveled over Asia and the Pacific Ocean before reaching the Rocky Mountains. Results from this study demonstrate that alpine ecosystems accumulate these chemicals to the same degree that is observed in polar environments that are known to receive contaminants by long-range transport.
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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) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 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".