Polybrominated Diphenyl Ethers in Indoor Dust in Ottawa, Canada: Implications for Sources and Exposure
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame retardants in plastics, soft furnishings, electrical and electronic equipment, and insulation in the indoor environment, and may be released indoors via volatilization or as dusts. The penta-and octa-brominated mixes are now banned in most parts of Europe, and phasing out of their use has recently begun in North America. This study follows a previous investigation into indoor air levels of PBDEs. House dust was analyzed from the family vacuum cleaners of 68 of the same 74 randomly selected homes, in Ottawa, Canada during the winter of 2002-2003. PBDEs, comprising on average 42% BDE-209, were found in all samples. The levels were log-normally distributed with a geometric mean sigmaPBDE of 2000 ng g(-1), and a median of 1800 ng g(-1) dust. The levels in dust did not correlate with questionnaire information on house characteristics. Correlations were found between pentamix congener levels in dust and in air from the same homes, but not for congeners of the more highly brominated mixes. Exposure scenarios are presented for mean and high dust ingestion rates, and compared against exposures from other pathways, for both adults and toddlers (6 months-2 years). Assuming a mean dust ingestion rate and median dust and air concentrations, adults would be exposed to ca. 7.5 ng sigmaPBDE d(-1) via the dust ingestion pathway, which represents approximately 14% of total daily exposure when compared to diet (82%) and inhalation (4%). However, for toddlers the equivalent intakes would be 99 ng d(-1), representing 80% of their daily PBDE exposure. At high dust ingestion rates these values increase to 180 ng d(-1) (80% daily intake) for adults and 360 ng d(-1) (89% daily intake) for toddlers. The data give a clearer picture of sources of PBDE exposure in the home environment and suggest that dust could be a significant exposure pathway for some individuals, particularly children.
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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 | 0.002 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 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 it