Interstudy and Intrastudy Temporal Trends of Polychlorinated Biphenyl, Pesticide, and Polycyclic Aromatic Hydrocarbon Concentrations in Air and Precipitation at a Rural Site in Ontario
Bibliographic record
Abstract
Polychlorinated biphenyl (PCB), organochlorine pesticide, and polycyclic aromatic hydrocarbon (PAH) concentrations were measured in air (in the vapor and particle phases) and in precipitation samples collected at Point Petre on the northeastern shore of Lake Ontario as a part of the Integrated Atmospheric Deposition Network. These data were measured in two separate studies, one running from 1992 to 2003 (inclusive) and the other from 1998 to 2011 (inclusive). Having these two independent studies is a direct way of measuring changes in atmospheric concentrations and comparing interstudy changes to intrastudy changes. The concentrations of almost all pesticides declined between the two studies with halving times of 3–6 years; the concentrations of PAHs and PCBs did not change much between the two studies. This suggests that there are continuing sources of PAHs and PCBs to the Great Lakes atmosphere. PAH concentrations were elevated in the winter when space heating consumes greater amounts of fuel and emits larger amounts of PAHs. Pesticide and PCB concentrations were elevated in the summer because of enhanced volatilization from terrestrial or aquatic surfaces during hot summer days. Although there were a few exceptions (notably lindane), in general, the data from the two study periods gave similar results.
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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 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".