Heterogeneity of soil hydraulic (e.g., hydraulic conductivity (KS), porosity (θS)) and chemical (e.g., solid-phase adsorption (Kd)) properties complicates contaminant transport by creating spatial variability in sources of contaminant leaching. There is a knowledge gap on the effect of the interplay between these properties on the retardation and transport of per- and polyfluoroalkyl substances (PFAS) with different properties including carbon–fluorine chain-length and functional groups even in water-saturated conditions. Breakthrough curves have been used to evaluate PFAS transport behavior through heterogeneous media, including arrival time, maximum concentration, and tailing behavior. Contaminant mass flux reduction and mass removal correlations are also compared using numerical modeling to characterize PFAS transport through different source zones within a two-domain, heterogeneous system with comparison to homogeneous scenarios under water-saturated conditions. With heterogeneous properties, model sensitivity to KS was the highest among the other parameters and was controlled by the KS ratio between the different soils. The PFAS models in the homogeneous and heterogeneous scenarios were both sensitive to θS, depending on PFAS chain length. However, long-chain PFAS were less sensitive to θS variability compared to short-chain PFAS due to their higher Kd. The homogeneous and heterogeneous scenarios were equally sensitive to Kd variability, which was dependent on PFAS chain length.

中文翻译：

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全氟烷基物质的质量通量降低和质量去除对地下水流和输运参数变化和非均质性的敏感性


土壤水力（例如，水力传导率 （KS）、孔隙率 （θS））和化学（例如，固相吸附 （Kd））特性的异质性通过在污染物浸出源中产生空间变化，使污染物运输复杂化。即使在水饱和条件下，这些特性之间的相互作用对具有不同特性（包括碳-氟链长度和官能团）的全氟烷基和多氟烷基物质 （PFAS） 的延迟和转运的影响也存在知识差距。突破曲线已用于评估 PFAS 通过非均质介质的运输行为，包括到达时间、最大浓度和拖尾行为。还使用数值建模比较了污染物质量通量减少和质量去除的相关性，以表征 PFAS 在两个域、异质系统中通过不同源区的传输，并与水饱和条件下的均质情景进行比较。在异质性方面，模型对 KS 的敏感性在其他参数中最高，并受不同土壤之间的 KS 比值控制。均相和异质情况下的 PFAS 模型都对 θS 敏感，具体取决于 PFAS 链的长度。然而，由于长链 PFAS 的 Kd 较高，因此与短链 PFAS 相比，长链 PFAS 对 θS 变异性不太敏感。均相和异质情景对 Kd 变异性同样敏感，而 Kd 变异性取决于 PFAS 链长。