New Sources of Very Persistent and Very Mobile (vPvM) Substances: A Case Study of the Fluorinated Herbicide Pyroxasulfone
Bibliographic record
Abstract
With the increasing use of fluorinated agrochemicals, more fluorinated compounds enter into the environment. Pyroxasulfone (PYS), a broad-spectrum herbicide containing an aromatic CF 3 (Ar–CF 3 ), is expected to grow significantly in application. Although several transformation products (TPs) of PYS have been reported, their distribution and contribution to transformation processes remain largely unknown. This study combined laboratory simulations and a field study. In soil incubation and soil surface photolysis experiments, (5-(difluoromethoxy)-1-methyl-3-(trifluoromethyl)-1 H -pyrazol-4-yl)methanesulfonic acid (TFPSA) was identified as the main TP of PYS in soil, accounting for over 90% of all TPs. Field study results showed that PYS and TFPSA were the main species in soil (6.48 ± 1.82 and 1.54 ± 0.90 ng g –1 wet weight) and corn plants (2.55 ± 2.61 and 31.1 ± 39.6 ng g –1 dry weight in roots) before harvest. Surface water photolysis experiments showed that TFPSA and TP 246 were the major TPs of PYS and no significant photodegradation of TFPSA was observed. Persistent (P) and mobile (M) property assessment indicated TFPSA, TP 246, and other Ar–CF 3 containing TPs of various fluorinated agrochemicals could be potential very P and very M (vPvM) substances. More attention should be paid to Ar–CF 3 containing agrochemicals and their TPs.
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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 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.000 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.001 |
| Research integrity | 0.001 | 0.001 |
| 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".