Quantification de la contamination dans le foie, les muscles et la graisse d’ours polaires de l’Arctique canadien.
Bibliographic record
Abstract
Depuis l'ère industrielle, les produits chimiques sont omniprésents dans les écosystèmes du monde entier. Cependant, malgré l'arrêt du rejet de plusieurs polluants organiques persistants (POP) hautement toxiques dans l'environnement, certains polluants sont toujours mesurés dans l'Arctique canadien. Ces contaminants sont très préoccupants en raison de leur persistance, de leur toxicité et de leur niveaux de bioaccumulation dans les chaînes alimentaires. Les animaux vivant dans l'Arctique, en particulier les ours polaires qui occupent une position trophique supérieure, sont exposés à ces contaminants principalement par leur alimentation. Notre étude a examiné les niveaux de biphényles polychlorés (BPC), de composés aromatiques polycycliques (CAP), de chlordanes (CHL) et de métaux (y compris le mercure total et le méthylmercure) chez 49 ours polaires de l'Arctique canadien. La charge de contaminants a été mesurée dans le foie, les muscles et la graisse chez des ours polaires de sexe, d'âge et de localisation différents. L'analyse en composantes principales n'était pas assez puissante pour distinguer les différences entre les profils d'âge et de sexe différents. Cependant, les concentrations mesurées et leur répartition dans les tissus confirment les résultats observés dans les études antérieures. Cette étude met en évidence l'importance d'un suivi continu de la santé des ours polaires (par exemple, de nouveaux CAP ont été mesuré par cette étude) et d'une évaluation des impacts de ceux-ci pour les prochaines générations. Since the industrial era, chemicals are ubiquitous in worldwide ecosystems. However, despite the discontinued release of highly toxic Persistent Organic Pollutants (POPs) in the environment, the levels of some persistent pollutants are still being measured in the Canadian Arctic. These contaminants are of great concern due to their persistence, toxicity, and levels of bioaccumulation in food chains. Animals living in the Arctic, in particular the polar bears, which occupy a top trophic position, are exposed to these contaminants mainly through their diet. Our study investigated the levels of (PCBs), polycyclic aromatic compounds (PACs), chlordanes (CHLs), and metals (including total and methyl mercury) in 49 polar bears from the Canadian Arctic. Contaminant burden was measured in liver, muscle and fat in bears of different sex, age and locations.A principal component analysis was not powerful enough to distinguish differences between profiles of different age and sex. However, the concentrations measured and their distribution in the tissues confirm findings observed in past studies. This study highlights the importance of a continual monitoring of polar bears health (e.g., newly PAC were measured within this study) and evaluation of the impacts of those for the next generations.
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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 | 0.001 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.001 |
| Bibliometrics | 0.002 | 0.002 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.003 | 0.001 |
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".