Evidence for Organic Film on an Impervious Urban Surface: Characterization and Potential Teratogenic Effects
Bibliographic record
Abstract
Chemical constituents of an organic film collected from an impervious urban surface, namely the exterior surface of windows, have been characterized. The organic portion of this film, that ranged in thickness from 11 to 100 nm, constitutes a previously unrecognized site for exchange of semivolatile organic contaminants in urban environments. The concentrations of total n -alkanes, total polycyclic aromatic compounds (PAH), and total polychlorinated biphenyls (PCB) ranged from 1010 to 22 500, 900 to 62 100, and 8 to 5820 ng/m 2 of window surface, respectively. Whereas concentrations varied, the patterns of chemical and congener abundance were similar among samples. Alkanes were derived from mainly biogenic sources, while the PAH showed a weathered pattern and PCB congener patterns generally indicated an enrichment in higher chlorinated congeners. Film-to-air partition ratios, K FA, were calculated for selected PAH and PCB congeners and were comparable to reported values of octanol−air partition coefficients, K OA, suggesting that gas-phase compounds partition into this organic film. Potential biological effects of an organic film extract were evaluated using zebrafish embryo assays. Incubation at a concentration of 270 ppb ΣPAH plus 420 ppb ΣPCB showed 100% lethality, while concentrations 3−10 times lower produced a dose-dependent syndrome of abnormalities including cardiovascular, hematopoietic, neural crest-related, and behavioral defects.
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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 | 0.000 |
| 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) | 0.001 | 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 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".