Manufactured Nanoparticle Migration in Groundwaters

纳米颗粒，至少一个维度不到百万分之一米的颗粒，越来越多地被认为具有非常有用的特性，用于非常广泛的应用，从自清洁表面到化妆品。这种特殊的性质源于极大的比表面积与微小颗粒的质量比。预计在不久的将来，人造纳米颗粒的生产和使用将大幅增加。这很可能导致自然环境受到污染，包括地下水(因此，可能还会污染地表水)。目前，每种类型的纳米颗粒对人类健康、对生态系统和对微生物群落的影响在很大程度上是未知的。因此，研究纳米颗粒在环境中的流动性是谨慎的。该项目致力于确定淡水地下水系统中金属氧化物纳米颗粒的流动性，这是一种非常常见的纳米颗粒类型。由于涉及的系统并不简单，而且这个项目很短，所以要开展的研究是范围而不是综合性的。该项目分为三个阶段：1.表征来自两个重要含水层岩石--砂岩和石灰岩的纳米颗粒和材料的大小、电荷/pH关系、矿物组成和水力特性(一些结果适用于一些天然砂岩，但没有适用于这些主要含水层类型)。2.使用第一阶段的结果，将选择三种类型的纳米颗粒来代表所制造的纳米颗粒的一系列性质。在之前NERC资助的二氧化硅胶体/病毒传输研究中开发的一个实验台，然后将被用来进行柱子实验，使用岩芯和适当的纳米颗粒悬浮液，这些悬浮液由去离子水或合成地下水溶液组成。3.进样悬浮液离开色谱柱时的浓度/时间曲线将使用各种方法进行解释，包括在前一次NERC研究中开发的数值模型，以得出：(A)金属氧化物纳米颗粒在基质孔隙系统中的可能迁移性；(B)控制观察到的任何衰减的主要因素；以及(C)先前对理想多孔介质中天然胶体传输和人造纳米颗粒传输所建议的定量描述的适用性。这项工作的成果将是识别影响金属氧化物制造的纳米颗粒通过砂岩和石灰岩孔隙水的主要过程。结果应至少定性地转移到其他类似的金属氧化物颗粒。结果将为评估此类系统的环境风险提供第一批可用数据，并可供监管机构(如英国环境局和美国环保局)使用。这项工作还将指出粒子输运现象的哪些方面是进一步研究中最关键的目标。

Nanoparticles, particles with at least one dimension of less than a tenth of a millionth of a metre, are increasingly being recognised as having very useful properties for a very wide range of applications, from 'self-cleaning' surfaces to cosmetics. The special properties arise from the very large surface area to mass ratio of tiny particles. Production and use of manufactured nanoparticles is expected to increase considerably in the near future future. This is likely to lead to contamination of the natural environment, including groundwaters (and thence, potentially, surface waters). At present the effects of each type of nanoparticle on human health, on ecosystems, and on microbial communities is largely unknown. It is therefore prudent to investigate the mobility of nanoparticles in the environment. This project is concerned with determining the mobility of metal oxide nanoparticles, a very common nanoparticle type, in fresh groundwater systems. Because the systems involved are not simple and this project is short, the research to be carried out is scoping in nature rather than comprehensive. The project is divided into three stages: 1. Characterization of the size, electrical charge/pH relationships, mineral composition, and hydraulic properties of nanoparticles and materials from two important aquifer rocks - sandstone and limestone (a few results are available for some natural sands, but none for these major aquifer types). 2. Using the results from Stage 1, three types of nanoparticle will be chosen to represent a range of manufactured nanoparticle properties. An experimental rig, developed in a previous NERC-funded study of silica colloid/virus transport, will then be used to carry out column experiments using rock cores and appropriate nanoparticle suspensions made up in deionized water or synthetic groundwater solutions. 3. Concentration/time curves for the injected suspension as it leaves the column will interpreted using various approaches, including a numerical model developed in the previous NERC study, to yield: (a) the likely mobility of metal oxide nanoparticles in matrix porewater systems; (b) the main factors controlling any attenuation observed; and (c) the applicability of previous quantitative descriptions suggested for natural colloid transport and transport of manufactured nanoparticles in idealized porous media. The product of the work will be the identification of the main processes affecting metal oxide manufactured nanoparticle passage through sandstone and limestone pore waters. The results should be transferable at least qualitatively to other similar metal oxide particles. The results will provide the first available data for assessing environmental risk in such systems, and could be used by regulatory authorities (e.g. the UK Environmnet Agency and the US EPA). The work will also indicate what aspects of the phenomena of particle transport are the most critical to target in further research.