Temporal Trends of Brominated and Fluorinated Contaminants in Canadian Arctic Beluga Delphinapterus leucas
Bibliographic record
Abstract
Limited information exists regarding contemporary and historical emissions for many anthropogenic chemicals, especially for contaminants of emerging concern (CECs). This study examined temporal trends of several perfluoroalkyl substances (PFASs), polybrominated diphenyl ethers (PBDEs), and hexabromocyclododecanes (HBCDs) in three beluga whale (Delphinapterus leucas) populations from the Canadian Arctic [Hendrickson Island (HI), NT; Pangnirtung (PG), NU; and Sanikiluaq (SQ), NU] collected from 1982 to 2013. The confounding factors of animal size, age, and sex were included in the analyses, but were only significant for some CECs. The strongest temporal resolution was obtained from HI, which showed increasing trends in PBDEs (4.8%/year) and HBCDs (2.9%/year), and decreases in perfluoroalkylcarboxylic acids (PFCAs, −6.0%/year). Concentrations of perfluorooctanesulfonate (PFOS) were relatively stable between 1984 and 2010, increasing substantially in 2011; trends in perfluorooctanesulfonamide (PFOSA) concentrations were not strictly linear over the study period. PBDE, HBCD, and PFCA trends in the HI population were opposite/different to that of many other arctic animals (e.g., polar bears) for the same time period. Trends were inconsistent among locations, suggesting that regional differences in dietary exposure and/or sources may also impact these trends. The effects of climate-change-driven processes on the exposure and distribution of CECs are currently not well understood, highlighting a need for ongoing contaminant monitoring.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.002 |
| Science and technology studies | 0.000 | 0.003 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 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 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".