Environmental fate of novel polyfluoroalkyl surfactants in surface soil
Bibliographic record
Abstract
The use of aqueous film forming foams (AFFFs) to extinguish accidental fires or for firefighting training purposes is a major source of perfluoroalkyl and polyfluoroalkyl substances (PFASs) to the environment. PFASs are recognized as contaminants of emerging concern due to their bioaccumulation, persistence and toxicity. Being designed to be chemically stable, PFASs remain in the environment for long periods of time. Consequently, the understanding of their environmental fate is of significance for the assessment, management and remediation of impacted sites. Recent reports on the presence of a large number of PFASs with non-fluorinated functionalities — referred to as novel — in AFFF formulations reveal a substantial knowledge gap in regards to their fate once released to the environment. The research starts by assessing the analytical techniques used to characterize PFASs in soil. Sites impacted by AFFFs are likely to present high concentrations of petroleum hydrocarbons. The effect of soil properties and hydrocarbon co-contamination on the extraction of PFASs from soil was studied. The extraction method developed was then used to characterize soils that were impacted by the firefighting effort following the accidental derailment of a train carrying crude oil in Lac-Mégantic, Québec, and to qualitatively and quantitatively characterize the PFAS contamination.Biotransformation was found to be a major environmental process undergone by AFFF components. Therefore, the biotransformation potential in soil of two fluorinated surfactants used in AFFF formulations was further investigated. Finally, the mobility in surface soils of nine PFASs relevant to AFFF formulations was explored through batch sorption experiments. The findings of this research emphasize the different behaviors of novel PFASs contained in AFFF formulations as opposed to the widely studied PFOS, PFOA and related perfluoroalkyl acids. As the presence of more novel PFASs is revealed across impacted sites, improved understanding of their environmental fate and effects is necessary for a proper assessment and management of such sites.
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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 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".