Biesek Barbara Jennifer, Szymkiewicz Adam, Šimůnek Jirka, Gumuła-Kawęcka Anna, Jaworska-Szulc Beata
Gdańsk University of Technology, Faculty of Civil and Environmental Engineering, ul. Gabriela Narutowicza 11/12, 80-233 Gdańsk, Poland.
Gdańsk University of Technology, Faculty of Civil and Environmental Engineering, ul. Gabriela Narutowicza 11/12, 80-233 Gdańsk, Poland.
Sci Total Environ. 2024 Jul 20;935:173252. doi: 10.1016/j.scitotenv.2024.173252. Epub 2024 May 18.
In this study, we investigated the effects of soil organic carbon (SOC) distribution and water uptake by plant roots on PFAS movement in the vadose zone with a deep groundwater table under temperate, humid climate conditions. Two series of numerical simulations were performed with the HYDRUS computer code, representing the leaching of historical PFOS contamination and the infiltration of water contaminated with PFOA, respectively. We considered soil profiles with three distributions of SOC (no SOC, realistic SOC distribution decreasing with depth, and uniform SOC equal to the content measured in topsoil), three root distributions (bare soil, grassland, and forest), and three soil textures (sand, sandy loam, and loam). The SOC distribution had a profound impact on the velocity of PFOS movement. The apparent retardation factor for realistic SOC distribution was twice as large as for the scenario with no SOC and more than three times smaller than for the scenario with uniformly high SOC content. We also showed that the root distribution in soil profoundly impacts the simulations of PFAS migration through soil. Including the root zone significantly slows down the movement of PFAS, primarily due to increased evapotranspiration and reduced downward water flux. Another effect of water uptake by plant roots is an increase of PFAS concentrations in soil water (evapo-concentration). The evapo-concentration and the slowdown of PFAS movement due to root water uptake are more significant in fine-textured soils than in sand.
在本研究中，我们调查了在温带湿润气候条件下，土壤有机碳（SOC）分布和植物根系对地下水埋深较深的包气带中全氟和多氟烷基物质（PFAS）运移的影响。使用HYDRUS计算机代码进行了两组数值模拟，分别代表历史全氟辛烷磺酸（PFOS）污染的淋溶以及受全氟辛酸（PFOA）污染的水的入渗。我们考虑了具有三种SOC分布（无SOC、随深度降低的实际SOC分布以及等于表土中测量含量的均匀SOC）、三种根系分布（裸土、草地和森林）以及三种土壤质地（砂土、砂壤土和壤土）的土壤剖面。SOC分布对PFOS的运移速度有深远影响。实际SOC分布下的表观阻滞因子是无SOC情景下的两倍，比均匀高SOC含量情景下小三倍多。我们还表明，土壤中的根系分布对PFAS在土壤中的迁移模拟有深远影响。包括根区在内会显著减缓PFAS的运移，主要原因是蒸散增加和向下的水流通量减少。植物根系吸水的另一个影响是土壤水中PFAS浓度增加（蒸发浓缩）。在质地较细的土壤中，由于根系吸水导致的PFAS蒸发浓缩和运移减缓比在砂土中更显著。
