Mercury Trends in Colonial Waterbird Eggs Downstream of the Oil Sands Region of Alberta, Canada
Bibliographic record
Abstract
Mercury levels were measured in colonial waterbird eggs collected from two sites in northern Alberta and one site in southern Alberta, Canada. Northern sites in the Peace-Athabasca Delta and Lake Athabasca were located in receiving waters of the Athabasca River which drains the oil sands industrial region north of Fort McMurray, Alberta. Temporal trends in egg mercury (Hg) levels were assessed as were egg stable nitrogen isotope values as an indicator of dietary change. In northern Alberta, California and Ring-billed Gulls exhibited statistically significant increases in egg Hg concentrations in 2012 compared to data from the earliest year of sampling. Hg levels in Caspian and Common Tern eggs showed a nonstatistically significant increase. In southern Alberta, Hg concentrations in California Gull eggs declined significantly through time. Bird dietary change was not responsible for any of these trends. Neither were egg Hg trends related to recent forest fires. Differences in egg Hg temporal trends between northern and southern Alberta combined with greater Hg levels in eggs from northern Alberta identified the likely importance of local Hg sources in regulating regional Hg trends. Hg concentrations in gull and Common Tern eggs were generally below generic thresholds associated with toxic effects in birds. However, in 2012, Hg levels in the majority of Caspian Tern eggs exceeded the lower toxicity threshold. Increasing Hg levels in eggs of multiple species nesting downstream of the oil sands region of northern Alberta warrant continued monitoring and research to further evaluate Hg trends and to conclusively identify sources.
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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 | 0.001 | 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".