Low-permeability aquitards can significantly affect the transport, distribution, and persistence of contaminant plumes in subsurface systems. Although such low-permeability materials are often charged, the key role of charge-induced electrostatic processes during contaminant transport has not been extensively studied. This work presents a detailed investigation exploring the coupled effects of heterogeneous distribution of physical, chemical and electrostatic properties on reactive contaminant transport in field-scale groundwater systems including spatially distributed clay zones. We performed an extensive series of numerical experiments in three distinct heterogeneous sandy-clayey domains with different levels of complexity. The flow and reactive transport simulations were performed by explicitly resolving the complex velocity fields, the small-scale electrostatic processes, the compound-specific diffusive/dispersive fluxes and the chemical processes utilizing a multi-continua based reactive transport code (MMIT-Clay). In each particular domain, numerical experiments were performed focusing on both the forward and back diffusion through the sandy-clayey interfaces. The results illuminate the control of microscopic electrostatic mechanisms on macroscopic mass transfer. Coulombic interactions in the clay's diffuse layer can significantly accelerate or retard a particular species depending on its charge. Furthermore, the chemical heterogeneity plays a major role in mass storage and release during reactive transport. Neglecting such processes can lead to substantial over- or underestimation of the overall transport behavior, which underlines the need for integrated physical, chemical and electrostatic approaches to accurately describe mass transfer processes in systems including low-permeability inclusions.

低渗透性的水基软化剂会严重影响地下系统中污染物羽流的运输，分布和持久性。尽管此类低渗透性材料经常带电，但在污染物传输过程中，电荷诱导的静电过程的关键作用尚未得到广泛研究。这项工作提出了一项详细的调查，探索物理，化学和静电性质的不均匀分布对田间规模地下水系统（包括空间分布的粘土区）中反应性污染物迁移的耦合影响。我们在三个不同的具有不同复杂程度的异质砂质-粘土域中进行了一系列的数值实验。通过显式解析复速度场来进行流动和反应输运模拟，小规模的静电过程，特定于化合物的扩散/分散通量以及利用基于多连续性的反应性传输代码（MMIT-Clay）的化学过程。在每个特定领域，均进行了数值实验，重点研究了通过沙质-黏土界面的向前和向后扩散。结果阐明了微观静电机理对宏观传质的控制。粘土扩散层中的库仑相互作用可以根据其电荷显着地加速或延迟特定种类。此外，化学异质性在反应运输过程中的大量存储和释放中起着重要作用。忽视这些过程可能会导致对整体运输行为的严重高估或低估，这突显了对整合的物理，