Tracing industrial ammonium in atmospheric deposition in the Athabasca Oil Sands Region, Alberta, Canada
Bibliographic record
Abstract
The expanding industrial development in the Athabasca oil sands region (AOSR) in northeastern Alberta,Canada, has raised concerns about increasing nitrogen (N) emissions from oil sands operations and theirpotential effects on the surrounding terrestrial and aquatic ecosystems. Stable isotope techniques may helpto trace industrial emissions provided that they are isotopically distinct from background isotope ratios ofatmospheric N compounds. Ammonium deposition rates (NH4-N) typically exceed nitrate deposition rates(NO3-N) in the AOSR (Proemse et al., 2013), suggesting that emissions of reduced nitrogen compoundsplay a significant role for the atmospheric nitrogen budget in the AOSR. We collected atmosphericammonium in open field bulk deposition and throughfall using ion exchange resins over ~6 months timeperiods from summer 2007 to summer 2011 located at distances between 3 to 113 km to one of the majoroil sands developments in the AOSR. Ammonium deposition rates and δ15N-NH4 values weredetermined using ion chromatography and the ammonium diffusion method (Sebilo et al., 2004) on resinextracts. Atmospheric ammonium deposition rates in open field bulk collectors and throughfall collectorsranged from 1.0 to 4.7 kg ha-1 yr-1 NH4-N, and from 1.0 to 18.3 kg ha-1 yr-1 NH4-N, respectively.δ15N-NH4 values varied from -6.3 to 14.8 with the highest δ15N values typically associated withelevated NH4-N deposition rates. δ15N-NH4 values of up to 20.1 were observed for industriallyemitted NH4 in particulate matter (PM2.5) emissions (Proemse et al., 2012) suggesting that industrialNH3 and NH4 emissions are associated with elevated δ15N values providing a potential tracer. Applyinga two-end-member mixing analysis using a background δ15N-NH4 value of -3.6 for summer and-3.2 for winter periods revealed that particularly sites within ~30km radius from the main oil sands developments are significantly affected by industrial contributions to atmospheric NH4 deposition.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.003 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.001 |
| 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".