Modeling per- and polyfluoroalkyl substance precursor transformation in groundwater at a well-characterized site

IF 5.5 3区环境科学与生态学 Q2 ENVIRONMENTAL SCIENCES

Journal of contaminant hydrology Pub Date : 2026-01-01 Epub Date: 2025-11-01 DOI:10.1016/j.jconhyd.2025.104766

Emily B. Stockwell , David T. Adamson , Jeff D. Gamlin , Poonam R. Kulkarni , Aman Singh , Ronald W. Falta , Charles J. Newell

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引用次数: 0

Abstract

Perfluoroalkyl acids (PFAAs) are a class of per- and polyfluoroalkyl substances (PFAS) that are mobile in groundwater, are not known to degrade, and are highly regulated. PFAAs can be generated by the transformation of certain PFAS compounds called precursors. A semi-analytical groundwater model that considers matrix diffusion was calibrated to field PFAS data at a site known to contain both PFAAs and their respective precursor compounds. The modeling effort considered four key PFAAs: perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorobutane sulfonate (PFBS). Individual precursor compounds were grouped together according to their ability to transform into one of these four key PFAAs.

Model calibration that varied source characteristics, fate and transport parameters, and precursor transformation indicated that precursor transformation could be a critical process for three of the four PFAAs: 40 years after the initial source release approximately 59%, 84%, and 87% of the PFOA, PFHxS, and PFBS plume maximum concentrations, respectively, originated from precursor transformation. In addition, precursor transformation led to PFOA, PFHxS, and PFBS plumes that were up to 17% longer than if precursor transformation did not occur. In contrast, PFOS was not substantially affected by precursor transformation due to high PFOS concentrations in the source zone compared to its precursors. Additional modeling of complete PFAS source removal indicated that the effects of matrix diffusion coupled with no natural degradation of certain PFAAs may result in PFAS plumes at this site that persist and are sustained by precursor transformation.

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模拟地下水中全氟烷基和多氟烷基物质前体转化。

全氟烷基酸（PFAAs）是一类单氟烷基和多氟烷基物质（PFAS），在地下水中可移动，已知不会降解，并受到高度管制。PFAAs可以通过某些称为前体的PFAS化合物的转化产生。考虑基质扩散的半解析地下水模型被校准为在已知含有PFAAs及其各自前体化合物的地点现场PFAS数据。建模工作考虑了四种关键的PFAAs：全氟辛烷磺酸（PFOS）、全氟辛酸（PFOA）、全氟己烷磺酸（PFHxS）和全氟丁烷磺酸（PFBS）。单个前体化合物根据其转化为这四个关键PFAAs之一的能力分组在一起。不同源特征、命运和转运参数以及前体转化的模型校准表明，前体转化可能是4种PFAAs中3种的关键过程：在初始源释放40年后，约59%、84%和87%的PFOA、PFHxS和PFBS羽流最大浓度分别来自前体转化。此外，前体转化导致PFOA、PFHxS和PFBS的羽流比未发生前体转化的羽流长17%。相比之下，由于源区的全氟辛烷磺酸浓度高于其前体，因此全氟辛烷磺酸不受前体转化的实质性影响。对PFAS源完全去除的额外建模表明，基质扩散加上某些PFAAs没有自然降解的影响可能导致PFAS羽流在该位点持续存在，并通过前体转化维持。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Journal of contaminant hydrology 环境科学-地球科学综合

CiteScore

6.80

自引率

2.80%

发文量

129

审稿时长

68 days

期刊介绍： The Journal of Contaminant Hydrology is an international journal publishing scientific articles pertaining to the contamination of subsurface water resources. Emphasis is placed on investigations of the physical, chemical, and biological processes influencing the behavior and fate of organic and inorganic contaminants in the unsaturated (vadose) and saturated (groundwater) zones, as well as at groundwater-surface water interfaces. The ecological impacts of contaminants transported both from and to aquifers are of interest. Articles on contamination of surface water only, without a link to groundwater, are out of the scope. Broad latitude is allowed in identifying contaminants of interest, and include legacy and emerging pollutants, nutrients, nanoparticles, pathogenic microorganisms (e.g., bacteria, viruses, protozoa), microplastics, and various constituents associated with energy production (e.g., methane, carbon dioxide, hydrogen sulfide). The journal''s scope embraces a wide range of topics including: experimental investigations of contaminant sorption, diffusion, transformation, volatilization and transport in the surface and subsurface; characterization of soil and aquifer properties only as they influence contaminant behavior; development and testing of mathematical models of contaminant behaviour; innovative techniques for restoration of contaminated sites; development of new tools or techniques for monitoring the extent of soil and groundwater contamination; transformation of contaminants in the hyporheic zone; effects of contaminants traversing the hyporheic zone on surface water and groundwater ecosystems; subsurface carbon sequestration and/or turnover; and migration of fluids associated with energy production into groundwater.