Polychlorinated Biphenyls in Global Air and Surface Soil: Distributions, Air−Soil Exchange, and Fractionation Effect
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
Polychlorinated biphenyl (PCB) concentrations in air and soil, measured by various research groups from around the world, were compiled and analyzed. Data for air were available from most regions, particularly in Europe and Asia. The average air concentrations (pg/m(3)) for SigmaPCB at background sites were 70 (5.1-170) for Europe, 79 (49-120) for North America, 66 (18-110) for South America, 270 (9-670) for Central America, 59 (17-150) for Asia, and 15 (13-17) for Australia. Data for soils exhibited better global coverage compared to air and were available from most regions. The average soil concentrations (pg/g dry weight) for SigmaPCB at background sites were 7500 (47-97 000) for Europe, 4300 (110-25 000) for North America, 1400 (61-9 500) for South America, 580 (120-2 900) for Asia, 390 (94-620) for Africa, and 280 (140-540) for Australia. Based on available studies where coupled measurements of PCBs in air and soil were made, the equilibrium status of PCBs in the air-soil system was investigated for China, West Midlands of the UK, central and southern Europe, and along a latitudinal transect from the south of the UK to the north of Norway. Differences were observed in plots of the soil-air equilibrium status (expressed as the soil-air fugacity fraction, ff) for different PCB homologues. This was explained by varying contributions from primary and secondary emissions-spatially and temporally. The net effect after several decades of PCB emissions to air, preferential transport of lower molecular weight PCBs through primary and secondary emission, and reductions in emissions to air in recent decades is that the lower molecular weight PCBs have achieved (and in some cases exceeded) soil-air equilibrium in many parts of the world. The exception is remote and background sites that are still dominated by primary sources.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 |
| 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 it