Investigating the Use of Hair to Assess Polybrominated Diphenyl Ether Exposure Retrospectively
Bibliographic record
Abstract
BACKGROUND: Polybrominated diphenyl ethers (PBDEs) are chemicals that are added to a variety of consumer products as flame-retardants and have been classified as emerging endocrine disruptors. They are persistent and have been detected in humans. Previous studies have suggested that hair is a suitable matrix for examining human exposure to organic pollutants such as PBDEs. It is believed that the majority of exposure is from our indoor environment. The aim of this study was to investigate the changes in PBDE patterns and levels along the hair shaft, by using segmental analysis to retrospectively assess long-term exposure over a 1-year period. METHODS: Questionnaires and hair samples from 65 women were collected at the Hospital for Sick Children, in Toronto, as part of a larger study. To assess long-term stability, hair samples were separated into 4- and 3-cm segments representing a 1-year period. Hair segments were analyzed for levels of 8 PBDE congeners, BDE-28, BDE-47, BDE-99, BDE-100, BDE-153, BDE-154, BDE-183, and BDE-209 on gas chromatography-mass spectrometry (MS). A Friedman test was used to detect the differences in exposure among segments, and factors such as dietary habits, hair care routine, and site of residence were investigated to determine if they might affect hair levels. RESULTS: A significant increase (P < 0.0001) in total PBDEs was seen among segments moving from proximal (root end) to distal along the hair shaft (median in pg/mg): first (33.3), second (43.0), third (61.6), and fourth (75.5) segments. Significantly lower levels of PBDEs were observed in artificially colored hair samples (P = 0.032), and a significant increase in PBDE levels was observed in women who consumed meat on a daily basis as opposed to weekly consumption (P = 0.040). CONCLUSIONS: The increase in PBDEs along the hair shaft suggests that hair PBDEs may be influenced by diet and artificial coloring. More work is needed to validate the use of PBDEs in hair as a biomarker of long-term exposure.
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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 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| 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 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".