(Primary Author) Department of Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX, 79409, USA.
Department of Civil, Environmental, and Construction Engineering, Texas Tech University, Lubbock, TX, 79409, USA.
Chemosphere. 2022 Sep;303(Pt 1):134686. doi: 10.1016/j.chemosphere.2022.134686. Epub 2022 Apr 27.
Per- and poly-fluoroalkyl substances (PFAS) are a group of anthropogenic, highly recalcitrant organic compounds consisting of thousands of individual species that are of increasing importance as groundwater contaminants. In-situ measurements of PFAS would be useful to better understand vertical profiles and mobility, contamination in partially saturated media, and to reduce sampling artifacts associated with groundwater collection and analysis. Diffusive equilibrium, high-resolution passive samplers (HRPPs) can be directly driven (>10 m) in sediments or groundwater. The samplers equilibrate with porewater through diffusion across the sampler membrane, providing high spatial resolution (sample every 20 cm) porewater concentrations of dissolved species. The objective of this study was to develop an HRPP to measure PFAS in contaminated groundwater and saturated media. To achieve this objective, a screening study was conducted to demonstrate quantitative measurement of selected PFAS as well as the kinetics of uptake into a sampler using both nylon and stainless steel membranes. Utilizing the results of the screening study, a prototype sampler was demonstrated in a laboratory flow box. Over a deployment period of 28 days, concentrations of several perfluoroalkyl carboxylic acids (PFCAs), a perfluoroalkyl sulfonate (PFSA), and a precursor PFAS reached equilibrium with porewater (sampler concentration >90 percent of porewater concentration). Application of these samplers could provide improved understanding of the behavior of PFAS in saturated or partially saturated groundwater systems and allow better assessment of fate and transport in the subsurface. Reliable subsurface site characterization will yield robust site assessments, conceptual models, and improve remediation designs as well as increase confidence in post remedial assessments at PFAS-impacted locations.
全氟和多氟烷基物质（PFAS）是一组人为的、高度稳定的有机化合物，由数千种不同的物质组成，由于它们是地下水污染物，因此变得越来越重要。原位测量 PFAS 将有助于更好地了解垂直分布和迁移、部分饱和介质中的污染情况，并减少与地下水采集和分析相关的采样人为误差。扩散平衡、高分辨率被动采样器（HRPP）可直接在沉积物或地下水中驱动（>10 m）。采样器通过穿过采样器膜的扩散与孔隙水达到平衡，从而提供高空间分辨率（每隔 20 cm 采样一次）的溶解物质孔隙水浓度。本研究的目的是开发一种 HRPP 来测量受污染地下水中的 PFAS 和饱和介质中的 PFAS。为了实现这一目标，进行了一项筛选研究，以证明使用尼龙和不锈钢膜可以定量测量选定的 PFAS 以及进入采样器的吸收动力学。利用筛选研究的结果，在实验室流动盒中对原型采样器进行了演示。在 28 天的部署期间，几种全氟烷基羧酸（PFCAs）、全氟烷基磺酸盐（PFSA）和一种前体 PFAS 的浓度与孔隙水达到平衡（采样器浓度>孔隙水浓度的 90%）。这些采样器的应用可以更好地了解 PFAS 在饱和或部分饱和地下水中的行为，并更好地评估地下水中的 fate 和 transport。可靠的地下场地特征描述将产生稳健的场地评估、概念模型，并改进修复设计，以及提高在受 PFAS 影响的地点进行修复后评估的信心。
