Uptake and elimination of perfluorinated phosphonic acids in the rat
Bibliographic record
Abstract
The mono- and di-substituted perfluorinated phosphonic acids (mono-PFPAs and di-PFPAs) are high production volume fluorinated surfactants. Mono-PFPAs have been observed in Canadian surface waters and wastewater treatment plant (WWTP) effluent. The first observation of the di-PFPAs in the environment is reported here, with the observation of the C6/C6 and C6/C8 di-PFPAs in the National Institute for Standards and Technology (NIST) WWTP sludge standard reference material (SRM) 2781. To characterize the risk associated with human exposure to the mono-PFPAs and di-PFPAs, we determined uptake and elimination parameters in the rat. After oral gavage all of the mono-PFPA and di-PFPA congeners were observed in the blood of the dosed animals. Half-lives after intraperitoneal dosing ranged from 0.96 +/- 0.11 to 2.8 +/- 0.5 days for the mono-PFPAs and 1.8 +/- 0.1 to 9.3 +/- 1.5 days for the di-PFPAs. These half-lives are of similar magnitude to those for perfluorooctane sulfonate (PFOS, 8 to 30 days in male rats) and perfluorooctanoate (PFOA, 6 days in male rats and 1 hour in female rats). Both PFOS and PFOA have human half-lives on the order of years, and so the mono-PFPAs and di-PFPAs may also have significant lifetimes in the human body. The analysis of paired whole blood and plasma samples demonstrated that the mono-PFPAs may bind to blood cells underestimating their concentration in plasma and sera samples. The biological fate of the mono-PFPAs and di-PFPAs determined here suggest there is the potential for human exposure and that if exposure does occur, they may be long-lived in the body.
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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 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".