Sorption of Perfluoroalkyl Phosphonates and Perfluoroalkyl Phosphinates in Soils
Bibliographic record
Abstract
Perfluoroalkyl phosphonates (PFPAs) and perfluoroalkyl phosphinates (PFPiAs) are recently discovered perfluoroalkyl acids (PFAAs) that have been widely detected in house dust, aquatic biota, surface water, and wastewater environments. The sorption of C6, C8, and C10 monoalkylated PFPAs and C6/C6, C6/C8, and C8/C8 dialkylated PFPiAs was investigated in seven soils of varying geochemical parameters. Mean distribution coefficients, log K d *, ranged from 0.2 to 2.1 for the PFPAs and PFPiAs and were generally observed to increase with perfluoroalkyl chain length. The log K d * of PFPiAs calculated here (1.6–2.1) were similar to those previously measured for the longer-chain perfluorodecanesulfonate (1.9, PFDS) and perfluoroundecanoate (1.7, PFUnA) in sediments, but overall when compared as a class, were greater than those for the perfluoroalkanesulfonates (−0.8–1.9, PFSAs), perfluoroalkyl carboxylates (−0.4–1.7, PFCAs), and PFPAs (0.2–1.5). No single soil-specific parameter, such as pH and organic carbon content, was observed to control the sorption of PFPAs and PFPiAs, the lack of which may be attributed to competing interferences in the naturally heterogeneous soils. The PFPAs were observed to desorb to a greater extent and likely circulate as aqueous contaminants in the environment, while the more sorptive PFPiAs would be preferentially retained by environmental solid phases.
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How this classification was reachedexpand
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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.001 | 0.010 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.002 | 0.002 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 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 teacher head, 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".