Evolving Accumulation\nof a Complex Profile of Polychlorinated\nAlkanes in Canadian Polar Bears
Bibliographic record
Abstract
Approximately 33 million t of polychlorinated alkanes (PCAs), also known as chlorinated paraffins, has been globally produced and used. Despite the higher bioaccumulation potential of PCAs in terrestrial ecosystems than in marine ecosystems, North American terrestrial PCA data are sparse and Arctic studies largely focus on short-chain PCAs, with minimal attention to longer-chain homologues in wildlife. This research delves into the dynamics of PCA accumulation and temporal changes across a broad spectrum of PCA homologues in polar bears (<i>Ursus maritimus</i>) from Hudson Bay. Subcutaneous fat samples collected over the past decade from adult male polar bears of the Western Hudson Bay (WHB) and Southern Hudson Bay (SHB) subpopulations were analyzed, identifying 109 of 545 PCA homologues, ranging from C<sub>8</sub> to C<sub>26</sub>. Analysis of 37 dietary fatty acids provided insights into dietary shifts and their influence on PCA profiles. Notably, SHB bears exhibited a decrease in PCA concentrations, reflecting marine food web influences. In contrast, WHB bears displayed increasing PCA levels, likely due to the use of more terrestrial and anthropogenic food sources. This study underscores the critical yet overlooked role of longer-chain PCAs in the Arctic food web and polar bear exposure, emphasizing the variance between subpopulations and the significant impact of dietary factors.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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 | 0.001 |
| 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) | 0.086 | 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 teacher head, 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".