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Per- and polyfluoroalkyl substances (PFASs) from aqueous film forming foams (AFFFs) can hinder bioremediation of co-contaminants such as trichloroethene (TCE) and benzene, toluene, ethylbenzene, and xylene (BTEX). Anaerobic dechlorination can require bioaugmentation of Dehalococcoides, and for BTEX, oxygen is often sparged to stimulate in situ aerobic biodegradation. We tested PFAS inhibition to TCE and BTEX bioremediation by exposing an anaerobic TCE-dechlorinating coculture, an aerobic BTEX-degrading enrichment culture, and an anaerobic toluene-degrading enrichment culture to n-dimethyl perfluorohexane sulfonamido amine (AmPr-FHxSA), perfluorohexane sulfonamide (FHxSA), perfluorohexanesulfonic acid (PFHxS), or nonfluorinated surfactant sodium dodecyl sulfate (SDS). The anaerobic TCE-dechlorinating coculture was resistant to individual PFAS exposures but was inhibited by >1000× diluted AFFF. FHxSA and AmPr-FHxSA inhibited the aerobic BTEX-degrading enrichment. The anaerobic toluene-degrading enrichment was not inhibited by AFFF or individual PFASs. Increases in amino acids in the anaerobic TCE-dechlorinating coculture compared to the control indicated stress response, whereas the BTEX culture exhibited lower concentrations of all amino acids upon exposure to most surfactants (both fluorinated and nonfluorinated) compared to the control. These data suggest the main mechanisms of microbial toxicity are related to interactions with cell membrane synthesis as well as protein stress signaling.

Due to a change in capital funding formula, many school boards across the Province of Ontario engaged in Accommodation Reviews to rationalize the supply of school capacity. This process led to numerous school closures and raised important policy questions regarding the economic value of a school in terms of its capitalization into property values and, by extension, how the closure of a school might affect local neighborhoods. To explore these questions, this research uses spatial hedonic methods to estimate the implicit value of accessibility to schools in the City of Hamilton, Ontario. Spatial Durbin model results provide evidence of a significant negative correlation between distance to schools and housing prices in the Canadian context. This suggests that accessibility to schools is capitalized into property values and that the closure of a neighborhood school may result in potentially significant losses of economic value in communities. [ABSTRACT FROM AUTHOR]

Only a fraction of the total number of per‐ and polyfluoroalkyl substances (PFAS) are monitored on a routine basis using targeted chemical analyses. We report on an approach toward identifying bioactive substances in environmental samples using effect‐directed analysis by combining toxicity testing, targeted chemical analyses, and suspect screening. PFAS compete with the thyroid hormone thyroxin (T4) for binding to its distributor protein transthyretin (TTR). Therefore, a TTR‐binding bioassay was used to prioritize unknown features for chemical identification in a PFAS‐contaminated sediment sample collected downstream of a factory producing PFAS‐coated paper. First, the TTR‐binding potencies of 31 analytical PFAS standards were determined. Potencies varied between PFAS depending on carbon chain length, functional group, and, for precursors to perfluoroalkyl sulfonic acids (PFSA), the size or number of atoms in the group(s) attached to the nitrogen. The most potent PFAS were the seven‐ and eight‐carbon PFSA, perfluoroheptane sulfonic acid (PFHpS) and perfluorooctane sulfonic acid (PFOS), and the eight‐carbon perfluoroalkyl carboxylic acid (PFCA), perfluorooctanoic acid (PFOA), which showed approximately four‐ and five‐times weaker potencies, respectively, compared with the native ligand T4. For some of the other PFAS tested, TTR‐binding potencies were weak or not observed at all. For the environmental sediment sample, not all of the bioactivity observed in the TTR‐binding assay could be assigned to the PFAS quantified using targeted chemical analyses. Therefore, suspect screening was applied to the retention times corresponding to observed TTR binding, and five candidates were identified. Targeted analyses showed that the sediment was dominated by the di‐substituted phosphate ester of N‐ethyl perfluorooctane sulfonamido ethanol (SAmPAP diester), whereas it was not bioactive in the assay. SAmPAP diester has the potential for (bio)transformation into smaller PFAS, including PFOS. Therefore, when it comes to TTR binding, the hazard associated with this substance is likely through (bio)transformation into more potent transformation products. Environ Toxicol Chem 2024;43:245–258. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. [ABSTRACT FROM AUTHOR]