Reduced Accessible Air–Water Interfacial Area Accelerates PFAS Leaching in Heterogeneous Vadose Zones
Reduced Accessible Air–Water Interfacial Area Accelerates PFAS Leaching in Heterogeneous Vadose Zones
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DOI：
10.1029/2022gl102655
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发表时间：
2023-04
影响因子：
5.2
通讯作者：
J. Zeng;B. Guo
中科院分区：
文献类型：
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作者：
J. Zeng;B. Guo
全氟烷基和多氟烷基物质（PFAS）是表面活性污染物，由于在空气-水和固体-水界面的吸附，在包气带中具有很强的保留性。PFAS通过包气带的沥滤造成地下水污染的巨大风险。以前的PFAS运输研究主要集中在均匀或分层的渗流区，显着低估了土壤异质性所造成的优先流的影响，已知的主要因素，主要控制地下运输的许多污染物。我们进行了数值模拟，调查优先流的影响PFAS浸出随机生成的非均质包气带。模拟结果表明，虽然短链PFAS经历了与非表面活性剂溶质类似的加速浸出，但由于沿沿着优先流动路径的可及空气-水界面面积减少，更表面活性的长链PFAS的加速浸出被独特地放大了1.1-4.5倍。我们的研究强调了表征土壤异质性对于准确预测包气带中长链PFAS淋溶的重要性。
Per‐ and polyfluoroalkyl substances (PFAS) are surface‐active contaminants experiencing strong retention in vadose zones due to adsorption at air–water and solid–water interfaces. Leaching of PFAS through vadose zones poses great risks of groundwater contamination. Prior PFAS transport studies have focused on homogenous or layered vadose zones that significantly underrepresented the impact of preferential flow caused by soil heterogeneities—a primary factor known to dominantly control the subsurface transport of many contaminants. We conduct numerical simulations to investigate the impact of preferential flow on PFAS leaching in stochastically generated heterogeneous vadose zones. The simulations show that while shorter‐chain PFAS experience accelerated leaching similar to non‐surfactant solutes, the accelerated leaching of more surface‐active longer‐chain PFAS is uniquely amplified by 1.1–4.5 times due to reduced accessible air–water interfacial areas along preferential flow pathways. Our study highlights the criticality of characterizing soil heterogeneities for accurately predicting the leaching of long‐chain PFAS in vadose zones.