Embryotoxicity of diluted bitumen applied to eggshells of wild double-crested cormorants and domestic chickens
Bibliographic record
Abstract
Breeding birds that become oiled may return to incubate their eggs, but even small quantities (≥1 mg) of conventional crude oils are embryotoxic when applied to the exterior of the eggshell. Therefore, we investigated whether an unconventional Alberta oil sands product, diluted bitumen (dilbit), was toxic to embryos of two species, domestic chickens (Gallus gallus) and wild double-crested cormorants (Phalacrocorax auritus). We incubated embryos in artificial egg incubators and applied various doses of lightly weathered dilbit (Cold Lake blend) ranging from 1 to 20 mg to the eggshells during early or late embryonic development. In both species, eggshell oiling with dilbit caused no significant decrease in embryo survival at sampling (80-85% embryonic development), and we found few effects on physiological endpoints related to growth, relative liver size (liver somatic index), and aerobic capacity. To investigate more subtle effects on liver function and metabolism associated with embryotoxicity, qPCR gene expression analyses on embryonic livers are underway and will be presented. We will also describe the physicochemical properties of the dilbit used in this study and its toxicity compared to similar studies with conventional crude oils. To date, this study indicates that even considerable amounts of lightly weathered dilbit transferred to the avian eggshell by incubating parents (up to 10-20 mg, approximately 9-19 µl) is unlikely to cause pre-hatch mortality in embryos of a domestic and wild avian species, although effects on gene expression are still under investigation.
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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 | 0.000 | 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) | 0.001 | 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".