Transport and mobilization of engineered nanoparticles in the vadose zone and groundwater

在过去的几十年里，工程纳米材料的使用越来越多，导致工程纳米颗粒释放到地下环境中。许多经过改造的纳米颗粒具有高度的反应性，可能会对人类和其他生物体造成广泛的损害。为了评估土壤和近地表沉积物中纳米颗粒污染的范围，以及用作饮用水水源的地下水含水层中纳米颗粒污染的潜在风险，更好地了解纳米颗粒如何在地下环境中被动员和运输是至关重要的。在过去的几年里，在理解纳米颗粒在地下水(饱和水介质)中的传输方面取得了一些进展。然而，我们对纳米颗粒如何在土壤和部分饱和沉积物(即包气带)中被动员和运输知之甚少。我的研究计划的总体目标是确定控制纳米颗粒在包气带和地下水中的迁移和迁移的主要因素，并开发一个数学模型来预测纳米颗粒在地下的迁移。我的短期目标包括进行实验室柱实验和理论建模研究，以：(I)研究纳米颗粒在均匀填充的多孔介质中的传输如何受到多孔介质类型、水分含量、纳米颗粒特性以及孔隙水流动和化学作用的影响，以及(Ii)研究非稳态流动和化学条件在纳米颗粒动员中的作用。长期而言，将在填充柱和完整的天然沉积物岩心中调查土壤质地和矿物学成分以及多孔介质结构(例如大孔隙)的影响。最终，将在一些现场研究纳米颗粒的动员和运输。这项研究将提供有关纳米颗粒在地下环境中迁移的宝贵知识，并有助于解决与纳米材料使用相关的环境风险问题。从这项研究中获得的知识将为加拿大政府制定适当的法规提供指导，这些法规旨在将纳米技术对环境的负面影响降至最低。

The increased use of engineered nanomaterials in the past few decades has resulted in release of engineered nanoparticles to subsurface environments. Many engineered nanoparticles are highly reactive and can cause extensive damage to humans and other organisms. To evaluate the scope of nanoparticle contamination in soil and near-surface sediments, and the potential risk of nanoparticle contamination of groundwater aquifers that are used as drinking water sources, a better understanding of how nanoparticles are mobilized and transported in subsurface environments is essential. In the last few years, some progress has been made in understanding nanoparticle transport in groundwater (water-saturated media). However, we know little about how nanoparticles are mobilized and transported in soil and partially-saturated sediments (i.e., the vadose zone). The overall objectives of my research program is to identify the major factors that control nanoparticle mobilization and transport in the vadose zone and groundwater, and to develop a mathematical model to predict nanoparticle migration in subsurface. My short-term objectives include doing laboratory column experiments and theoretical modeling studies to: (i) examine how nanoparticle transport in uniformly-packed porous medium is influenced by porous medium type, moisture content, nanoparticle properties, and pore water flow and chemistry, and (ii) investigate the role of non-steady state flow and chemical conditions in nanoparticle mobilization. In the long term, the influence of soil texture and mineralogical components, as well as porous medium structure (e.g., macropores), will be investigated in packed columns and intact natural sediment cores. Eventually nanoparticle mobilization and transport will be studied at a number of field sites. This research will provide valuable knowledge on nanoparticle migration in subsurface environments and help address concerns over environmental risks associated with nanomaterial usage. The knowledge gained from this research will offer guidance to the Canadian government for developing proper regulations that are aimed at minimizing negative environmental impacts of nanotechnology.