Survey of persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) in the atmosphere of rural, urban and industrial areas of Concepción, Chile, using passive air samplers
Bibliographic record
Abstract
Passive air samplers (PAS) consisting of polyurethane foam (PUF) disks were used to assess air concentrations of polychlorinated biphenyl (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polybrominated diphenyl ethers (PBDEs) in rural, urban, and industrial sites in Concepción, Chile during a two-month deployment in the summer of 2007. Results for PCBs and PAHs showed a clear rural-urban-industrial gradient. PCB air concentrations (pg m−3) ranged from -30 to -350 and were ~2 to 5 times higher at industrial sites compared to rural sites. For PAHs, air concentrations (ng m−3) ranged from 26 to 230 and were 4 to 8 times higher at industrial sites. The PCB congener profile was dominated by high molecular weight PCBs at urban and industrial sites. The PAH profile was dominated by 3- and 4-ring PAHs accounting for more than 90% of the Σ15PAH, and dominated by phenanthrene (~40%). Of the HCH isomers, only y–HCH was detected with air concentrations ranging from 5 to 120 pg m−3. While for DDT isomers, p,p’–DDE was the only compound detected, ranging from below detection limit (BDL) to 360 pg m−3. Other OCPs (chlordanes, heptachlor and Dieldrin) showed low air concentrations (pg m−3) on the order of ~-1 - 3. Endosulfan, which is a newly listed persistent organic pollutant (POP) under the Stockholm Convention (SC) on POPs, ranged from 14 to 20 pg m−3. Polybrominated diphenyl ethers (PBDEs) also newly listed under the SC, were relatively uniform across the transect with air concentrations (pg m−3) in the range of ~5 to 10. This study represents one of the first efforts to characterize the POPs composition in ambient air for urban and industrial areas of Chile.
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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) | 0.001 | 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 | 0.001 |
| 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".