School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Center for Environmental Nanoscience and Risk (CENR), Department of Environmental Health Sciences, Arnold School of Public Health, University of South Carolina, Columbia, 29208, USA.
Chemosphere. 2018 Jan;191:616-625. doi: 10.1016/j.chemosphere.2017.10.006. Epub 2017 Oct 23.
Understanding the environmental behaviour of nanoparticles (NPs) after release into aquatic systems is essential to predict the environmental implications of nanotechnology. Silver nanoparticles (AgNPs) represent a major class of engineered NPs with a significant potential for environmental impact. Therefore, investigating their transformations in natural waters will help predict their long term environmental fate and behaviour. AgNPs were characterized in natural lake water collected seasonally from the same freshwater source, using column microcosms to assess their behaviour and transport at different depths. Building on our previous work using similar systems with synthetic waters, the influence of water chemistry and NP surface modifications on colloidal stability and dissolution in natural lake water over time was investigated. A simple sedimentation-diffusion model parameterized by the particle properties and total Ag concentration was successfully used to understand AgNPs transport behaviour. PVP coated AgNPs remained colloidally stable, with their transport in the water column dominated by diffusion, and exhibited no significant or substantial changes in data or model parameters for different seasons. Citrate coated AgNPs were susceptible to rapid aggregation, sedimentation, dissolution and reprecipitation; their transport in the water column was determined by both diffusion and sedimentation.
了解纳米颗粒（NPs）释放到水生系统后的环境行为对于预测纳米技术的环境影响至关重要。银纳米颗粒（AgNPs）是一类主要的工程纳米颗粒，具有很大的环境影响潜力。因此，研究它们在天然水中的转化将有助于预测它们的长期环境归宿和行为。本研究使用柱微宇宙从同一淡水来源季节性采集的天然湖水对 AgNPs 进行了表征，以评估它们在不同深度的行为和迁移。基于我们之前使用类似的合成水系统进行的研究，本研究考察了水化学和 NP 表面修饰对胶体稳定性和天然湖水中 AgNPs 溶解的影响。通过颗粒特性和总 Ag 浓度参数化的简单沉淀-扩散模型成功地用于理解 AgNPs 的迁移行为。PVP 包覆的 AgNPs 保持胶体稳定，其在水柱中的迁移主要由扩散控制，并且在不同季节的数据或模型参数上没有显著或实质性的变化。柠檬酸包覆的 AgNPs 容易发生快速聚集、沉淀、溶解和再沉淀；它们在水柱中的迁移既受扩散控制，也受沉淀控制。
