Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
SiREM, Guelph, Ontario, N1G 3Z2, Canada.
Environ Sci Process Impacts. 2023 May 25;25(5):980-995. doi: 10.1039/d2em00483f.
A simple equilibrium passive sampler, consisting of water in an inert container capped with a rate-limiting barrier, for the monitoring of per- and polyfluoroalkyl substances (PFAS) in sediment pore water and surface water was developed and tested through a series of laboratory and field experiments. The objectives of the laboratory experiments were to determine (1) the membrane type that could serve as the sampler's rate-limiting barrier, (2) the mass transfer coefficient of environmentally relevant PFAS through the selected membrane, and (3) the performance reference compounds (PRCs) that could be used to infer the kinetics of PFAS diffusing into the sampler. Of the membranes tested, the polycarbonate (PC) membrane was deemed the most suitable rate-limiting barrier, given that it did not appreciably adsorb the studied PFAS (which have ≤8 carbons), and that the migration of these compounds through this membrane could be described by Fick's law of diffusion. When employed as the PRC, the isotopically labelled PFAS MPFOA and MPFOS were able to predict the mass transfer coefficients of the studied PFAS analytes. In contrast, the mass transfer coefficients were underpredicted by Br and MPFPeA. For validation, the PC-based passive samplers consisting of these four PRCs, as well as two other PRCs (, MPFOA and CHSO), were deployed in the sediment and water at a PFAS-impacted field site. The concentration-time profiles of the PRCs indicated that the samplers deployed in the sediment required at least 6 to 7 weeks to reach 90% equilibrium. If the deployment times are shorter (, 2 to 4 weeks), PFAS concentrations at equilibrium could be estimated based on the concentrations of the PRCs remaining in the sampler at retrieval. All PFAS concentrations determined this approach were within a factor of two compared to those measured in the mechanically extracted sediment pore water and surface water samples obtained adjacent to the sampler deployment locations. Neither biofouling of the rate-limiting barrier nor any physical change to it was observed on the sampler after retrieval. The passive sampler developed in this study could be a promising tool for the monitoring of PFAS in pore water and surface water.
开发并通过一系列实验室和现场实验测试了一种简单的平衡型被动采样器，该采样器由惰性容器中的水和限流器组成，用于监测沉积物孔隙水和地表水的全氟和多氟烷基物质（PFAS）。实验室实验的目的是确定（1）可作为采样器限流器的膜类型，（2）通过所选膜传递环境相关 PFAS 的质量转移系数，以及（3）可用于推断 PFAS 扩散到采样器中的动力学的性能参考化合物（PRC）。在所测试的膜中，聚碳酸酯（PC）膜被认为是最合适的限流器，因为它不会明显吸附研究的 PFAS（这些 PFAS 的碳数≤8），并且这些化合物通过该膜的迁移可以用菲克扩散定律来描述。当用作 PRC 时，同位素标记的 PFAS MPFOA 和 MPFOS 能够预测研究的 PFAS 分析物的质量转移系数。相比之下，Br 和 MPFPeA 则低估了质量转移系数。为了验证，基于这四种 PRC 以及另外两种 PRC（，MPFOA 和 CHSO）的 PC 基被动采样器被部署在受 PFAS 影响的现场的沉积物和水中。PRC 的浓度-时间曲线表明，部署在沉积物中的采样器至少需要 6 到 7 周才能达到 90%平衡。如果部署时间更短（，2 到 4 周），则可以根据回收时采样器中残留的 PRC 的浓度估算平衡时的 PFAS 浓度。通过这种方法确定的所有 PFAS 浓度与在采样器部署位置附近获得的机械提取的沉积物孔隙水和地表水样品中测量的浓度相比，均在两倍以内。回收后，在采样器上未观察到限流器的生物污垢或对其的任何物理变化。本研究中开发的被动采样器可能是监测孔隙水和地表水 PFAS 的有前途的工具。
