PFAS quantitation with diffusive gradients in thin-film passive samplers: Capturing time-weighted average concentrations around maximum contaminant levels to facilitate compliance.

Λεπτομέρειες βιβλιογραφικής εγγραφής
Τίτλος:	PFAS quantitation with diffusive gradients in thin-film passive samplers: Capturing time-weighted average concentrations around maximum contaminant levels to facilitate compliance.
Συγγραφείς:	Harris BJ; Department of Civil Engineering, University of Arkansas, Fayetteville, AR 72701, USA., Hodges SD; Department of Civil Engineering, University of Arkansas, Fayetteville, AR 72701, USA., Wahman DG; U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA., Haupert LM; U.S. Environmental Protection Agency, Cincinnati, OH 45268, USA., Chimka JR; Department of Industrial Engineering, University of Arkansas, Fayetteville, AR 72701, USA., Fairey JL; Department of Civil Engineering, University of Arkansas, Fayetteville, AR 72701, USA. Electronic address: julianf@uark.edu.
Πηγή:	Water research [Water Res] 2026 Aug 01; Vol. 300, pp. 125918. Date of Electronic Publication: 2026 Apr 12.
Τύπος έκδοσης:	Journal Article
Γλώσσα:	English
Στοιχεία περιοδικού:	Publisher: Pergamon Press Country of Publication: England NLM ID: 0105072 Publication Model: Print-Electronic Cited Medium: Internet ISSN: 1879-2448 (Electronic) Linking ISSN: 00431354 NLM ISO Abbreviation: Water Res Subsets: MEDLINE
Imprint Name(s):	Original Publication: Oxford, Pergamon Press.
Ιατρικοί όροι (MeSH):	Environmental Monitoring/methods , Environmental Monitoring/instrumentation , Water Pollutants, Chemical/analysis , Fluorocarbons/analysis, Diffusion
Περίληψη:	Diffusive gradients in thin-films (DGT) passive samplers are used to quantify analytes in water, but their capabilities for capturing time-weighted average concentrations (CDGT) of per- and polyfluoroalkyl substances (PFAS) at low ng L^-1 levels are unknown. For 32 PFAS, DGT passive sampler gel layer diffusion coefficients (DGel) ± 95 % confidence intervals (CIs) were determined using two-compartment diffusion cell tests analyzed with a non-steady-state finite difference model (FDM), which was previously shown to produce DGel estimates with less error than traditional methods relying on a pseudo-steady-state flux assumption. For each PFAS, the FDM also determined the normalized weighted sum of squared errors (WSSE × n^-1), a goodness of fit measure. Eleven PFAS had adequate FDM fits (WSSE × n^-1 < 0.03) and DGel ± 95 % CIs decreased with increasing molecular weight (MW) from 7.1 to 5.1 (± 0.1-0.6) × 10^-6 cm² s^-1. For the other 21 PFAS, linear regression models (DGel vs. MW; R² ≥ 0.967) were used to estimate DGel ± 95 % CIs from 3.4 to 7.6 (± 0.2-1.0) × 10^-6 cm² s^-1. Compared to their free water diffusivities, DGel values differed by a median of 6.5 % and first and third quartiles of 4.5 and 8.7 %, respectively. Error in DGel was propagated into CDGT for 5-36-day laboratory-scale DGT deployments, in which CDGT ± 95 % CIs for 20-31 of the 32 PFAS were indistinguishable from grab samples (sign test; α = 0.05). DGTs accurately captured time-weighted average PFAS aqueous phase concentrations at ∼1, 10, 100, and 200 ng L^-1. This study demonstrates the utility of DGTs for PFAS quantitation at low ng L^-1 levels and establishes methods for PFAS DGel determinations, error propagation into CDGT, and comparisons with grab sampling. (Copyright © 2026 The Author(s). Published by Elsevier Ltd.. All rights reserved.)
Competing Interests:	Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Contributed Indexing:	Keywords: Diffusion coefficients; Environmental sampling; Finite difference model; Time-weighted average
Substance Nomenclature:	0 (Water Pollutants, Chemical) 0 (Fluorocarbons)
Entry Date(s):	Date Created: 20260416 Date Completed: 20260715 Latest Revision: 20260715
Update Code:	20260715
DOI:	10.1016/j.watres.2026.125918
PMID:	41990621
Βάση Δεδομένων:	MEDLINE

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