Determination of Firefighter Exposure to Polycyclic Aromatic Hydrocarbons and Benzene During Fire Fighting Using Measurement of Biological Indicators
Bibliographic record
Abstract
In accomplishing their duties, firefighters are potentially exposed to a vast array of toxic combustion and pyrolysis products such as benzene, carbon monoxide, acrolein, nitrogen dioxide, and polycyclic aromatic hydrocarbons. Exposure to PAH and benzene was assessed by means of urinary measurements of 1-hydroxypyrene and t,t-muconic acid, respectively. All urine samples were collected from 43 firefighters during a period extending for 20 h following the end of exposure during a fire. A control sample was also obtained from each participant after at least four days without involvement in fire fighting activities. Only one control 1-hydroxypyrene measurement exceeded the value of 0.32 micromol/mol creatinine considered as the 95th percentile of a normal reference population in this study. Following exposure, 38 percent of the maximum values of all samples collected from each firefighter exceeded this reference value. The highest single value observed in this study was 3.6 micromol/mol creatinine. None of the control samples had a t,t-muconic acid concentration above the limit of detection. A large number (81%) of post-fire samples also had nonquantifiable concentrations of this metabolite. Among 43 firefighters in this study, 17 had measurable excretion of this metabolite in any of the urine samples after fire fighting and, of the latter group, only 6 had t,t-muconic acid concentrations exceeding 1.1 mmol/mol creatinine, a value considered to correspond to a benzene-air concentration of approximately 1 ppm according to the literature. There is clear evidence that fire fighting activities are associated with exposure to PAH above environmental background, as assessed by 1-hydroxypyrene measurements, despite the use of protective equipment. However, in comparison with observations made in other cohorts of industrial workers with known polycyclic aromatic hydrocarbons exposure, firefighters' exposure in this study was low. Similarly, based on t,t-muconic acid determinations, exposure to benzene was rather low in this study. For both contaminants, observation of low exposure could be due to either low concentrations of the contaminant during fire fighting or to the efficiency of protective equipment worn.
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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 | 0.001 |
| 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 | 0.000 | 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".