School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, USA.
Sci Total Environ. 2015 Jul 15;521-522:183-90. doi: 10.1016/j.scitotenv.2015.03.093. Epub 2015 Mar 30.
Once released into the aquatic environment, nanoparticles (NPs) are expected to interact (e.g., dissolve, agglomerate, settle), with important consequences for particle fate and toxicity. However, a clear understanding of how environmental factors influence the toxicity and fate of NPs in the environment is still in its infancy. In this study, a second order central composite circumscribed design (CCCD) was employed to systematically explore how different combinations of pH, hardness, and natural organic matter (NOM) in receiving water affect the hydrodynamic diameter, surface charge (zeta potential), and release of free Cu(2+) from CuO-NPs under a range of environmentally realistic conditions. The results clearly showed that all three CuO-NP properties varied markedly as functions of pH, hardness and dissolved NOM, confirming that agglomeration and the extent of release of free Cu(2+) largely depend on the surrounding environmental conditions. The response of hydrodynamic diameter, but not zeta potential, to water quality parameters was highly time dependent, showing very different patterns on day 2 and day 10. The approach used in this study can contribute to improving understanding of how, and to what extent, environmental factors affect the physicochemical properties of CuO-NPs once they enter aquatic environments. This understanding can help to predict the conditions under which CuO-NPs are likely to become problematic, which can inform management and mitigation actions.
一旦纳米颗粒（NPs）被释放到水生环境中，预计它们将与环境相互作用（例如溶解、聚集、沉降），这对颗粒的归宿和毒性具有重要影响。然而，对于环境因素如何影响纳米颗粒在环境中的毒性和归宿，我们仍缺乏清晰的认识。在本研究中，采用二阶中心复合边界设计（CCCD）系统地探讨了受纳水中不同 pH 值、硬度和天然有机物（NOM）组合如何在一系列实际环境条件下影响 CuO-NPs 的水动力直径、表面电荷（zeta 电位）和游离 Cu（2+）的释放。结果清楚地表明，所有三种 CuO-NP 特性都明显随 pH 值、硬度和溶解 NOM 的变化而变化，这证实了聚集和游离 Cu（2+）的释放程度在很大程度上取决于周围的环境条件。水动力直径对水质参数的响应高度依赖于时间，在第 2 天和第 10 天表现出非常不同的模式，而 zeta 电位则不然。本研究中采用的方法有助于提高我们对环境因素如何以及在何种程度上影响 CuO-NPs 进入水生环境后的物理化学性质的认识。这种认识有助于预测 CuO-NPs 可能出现问题的条件，从而为管理和缓解措施提供信息。
