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Release of Per- and Polyfluoroalkyl Substances from Aqueous Film-Forming Foam Impacted Soils
Environmental Science & Technology ( IF 10.8 ) Pub Date : 2021-10-19 , DOI: 10.1021/acs.est.1c02871
Andrew C Maizel 1 , Stefanie Shea 1 , Anastasia Nickerson 1 , Charles Schaefer 2 , Christopher P Higgins 1
Affiliation  

Per- and polyfluoroalkyl substances (PFASs) are highly mobile in the saturated subsurface, yet aqueous film-forming foam (AFFF)-impacted source zones appear to be long lasting PFAS reservoirs. This study examined the release of over one hundred anionic and zwitterionic PFASs from two AFFF-impacted surface soils under saturated conditions with packed soil columns. Perfluoroalkyl acids (PFAAs) were released more rapidly than their polyfluorinated precursors, while anionic PFASs that were present in partially uncharged states were released more slowly than PFASs that were present entirely as anions, as were zwitterionic PFASs with terminal cationic functional groups when compared with analogous zwitterions with only anionic terminal groups. Nonideal transport was observed in both per- and polyfluorinated classes, as soil column effluent concentrations of slowly released PFASs increased by up to 107-fold with sustained artificial groundwater flow. A flow-interruption experiment suggested the influence of rate-limited desorption on diverse PFAS classes, including PFAAs with as few as four perfluorinated carbons. These results suggest that during infiltration the slow, rate-limited desorption of anionic and zwitterionic PFAA precursors may result in these compounds comprising an increasingly large fraction of the remaining PFASs in AFFF-impacted surface soils.

中文翻译:

水成膜泡沫影响土壤中全氟和多氟烷基物质的释放

全氟烷基物质和多氟烷基物质 (PFAS) 在饱和的地下具有高度流动性,但受水成膜泡沫 (AFFF) 影响的源区似乎是持久的 PFAS 储层。这项研究检查了在饱和条件下,在填充土柱的饱和条件下,两种受 AFFF 影响的表层土壤中超过 100 种阴离子和两性离子 PFAS 的释放。全氟烷基酸 (PFAA) 比其多氟前体释放得更快,而以部分不带电状态存在的阴离子 PFAS 比完全以阴离子形式存在的 PFAS 释放得更慢,与类似物相比,具有末端阳离子官能团的两性离子 PFAS 也是如此仅具有阴离子端基的两性离子。在全氟和多氟类中都观察到了非理想的传输,随着持续的人工地下水流,土壤柱流出物中缓慢释放的全氟和多氟烷基物质的浓度增加了 107 倍。流动中断实验表明限速解吸对不同 PFAS 类别的影响,包括具有少至四个全氟化碳的 PFAA。这些结果表明,在渗透过程中,阴离子和两性离子 PFAA 前体的缓慢、限速解吸可能导致这些化合物在受 AFFF 影响的表层土壤中包含越来越多的剩余 PFAS。
更新日期:2021-11-02
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