Concentrations, gas–particle distributions, and source indicator analysis of brominated flame retardants in air at Toolik Lake, Arctic Alaska
Bibliographic record
Abstract
Brominated flame-retardants (BFRs) can be released from consumer products, resulting in accumulation in the surrounding environment and/or long-range transport to remote environments. We evaluated concentration changes in a suite of BFRs, including 13 polybrominated diphenyl ethers (PBDEs) and 1,2-bis(2,4,6-tribromophenoxy)ethane (BTBPE), in air at Toolik Lake, Arctic Alaska during the Northern Hemisphere summer of 2013. A high-volume active air sampler was used to collect 2 day integrated samples at the field station and three flow-through air samplers were used to collect 18 day integrated samples along a transect extending away from the field station. The BDE congeners associated with the penta-BDE commercial mixture (BDE-47, -99, and -100) were the most frequently detected BFRs and were found at concentrations consistent with those reported at other Arctic sites. Gas-particle distributions were influenced by temperature and correlations between gas-phase concentrations and temperature suggested that either volatilization from local sources or re-emission from secondary sources (that is, re-volatilization of BFRs that had migrated northwards from distant sources) was important for the lower-brominated BFRs during the warmer months. Source indicator analysis suggested no single dominant geographic source of BFRs while results from the flow-through samplers indicated that the field station itself was not a significant source of BFRs.
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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) | 0.000 | 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".