Adsorption of perfluorooctane sulfonic acid (PFOS) onto various solid matrices
Bibliographic record
Abstract
Per- and poly-fluoroalkyl substances (PFAS) represent a group of pollutants extensively utilized in various industrial and commercial sectors over the past six decades. Of specific concern in this study is the utilization of Aqueous Film-Forming Foams (AFFFs) by firefighters during firefighting training exercises, which results in PFAS compounds seeping into the subsurface and drinking water supplies. The consequent contamination poses a significant health hazard to nearby communities. Adequate characterization of geochemical processes and other field-specific parameters can elucidate the understanding of PFAS sorption process and improve predictions of fate and transport models. This study presents an assessment of perfluorooctane sulfonic acid (PFOS) adsorption onto an iron-rich soil sampled from a AFFF contamination site in Killingworth, CT, 2-line ferrihydrite, Ottawa sand, and iron-coated sand. Batch adsorption experiments were performed to assess the effect of pH on PFOS adsorption, and soil-water partition coefficients (Kd) were calculated. Increased adsorption to Killingworth soil and iron-coated sand was observed at low pH values, indicating that surface charge and electrostatic interactions are significant for iron minerals and iron-rich soils. Adsorption to similar soils may affect PFOS transport at polluted sites like Killingworth, CT, especially in acidic conditions. PFOS adsorption to Ottawa sand was lower than other solid matrices at low pH values, indicating that non-electrostatic retention mechanisms may be dominant.
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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 | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.008 | 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; both teacher heads agree on what is shown here.
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".