In Situ Liquid Cell Observations of Asbestos Fiber Diffusion in Water.
In Situ Liquid Cell Observations of Asbestos Fiber Diffusion in Water.
复制标题
石棉纤维在水中扩散的原位液体细胞观察。
DOI：
10.1021/acs.est.5b03839
复制
发表时间：
2015
影响因子：
11.4
通讯作者：
Jerolmack,Douglas
中科院分区：
文献类型：
--
作者：
Wu,Lei;Ortiz,Carlos;Xu,Ye;Willenbring,Jane;Jerolmack,Douglas
我们提出了实时观测个别石棉纤维在水中的扩散。我们首先扩大了温石棉纤维的荧光标记和成像技术，并制备了纤维长度分布为1至20 μm的样品。然后通过将这些纤维的20、100或150 ppm溶液置于安装在旋转盘共聚焦显微镜上的液体池中进行实验。使用自动椭圆粒子检测方法，我们确定了数以千计的扩散温石棉纤维的平移和旋转以及二维（2D）轨迹。我们发现，纤维扩散是尺寸相关的，并在合理的协议与理论预测的布朗运动杆。这种一致性是显着的，因为实验涉及非理想化的粒子在环境相关的浓度在一个封闭的细胞，其中粒子-粒子和粒子-壁的相互作用可能会导致偏离理论。实验还证实，高度拉长的温石棉纤维在短时间内表现出各向异性扩散，这种预测效应可能会对密闭空间内石棉的聚集体形成和迁移产生影响。所研究的纤维在其长度上变化很大，并从天然温石棉制备。因此，我们的研究结果表明，广泛的天然胶体颗粒的扩散速率可以从理论上预测，只要适当地考虑到颗粒的纵横比。这是了解非球形污染物颗粒在环境和体内聚集体形成和运输的重要的第一步。
We present real-time observations of the diffusion of individual asbestos fibers in water. We first scaled up a technique for fluorescent tagging and imaging of chrysotile asbestos fibers and prepared samples with a distribution of fiber lengths ranging from 1 to 20 μm. Experiments were then conducted by placing a 20, 100, or 150 ppm solution of these fibers in a liquid cell mounted on a spinning-disk confocal microscope. Using automated elliptical-particle detection methods, we determined the translation and rotation and two-dimensional (2D) trajectories of thousands of diffusing chrysotile fibers. We find that fiber diffusion is size-dependent and in reasonable agreement with theoretical predictions for the Brownian motion of rods. This agreement is remarkable given that experiments involved non-idealized particles at environmentally relevant concentrations in a confined cell, in which particle–particle and particle–wall interactions might be expected to cause deviations from theory. Experiments also confirmed that highly elongated chrysotile fibers exhibit anisotropic diffusion at short time scales, a predicted effect that may have consequences for aggregate formation and transport of asbestos in confined spaces. The examined fibers vary greatly in their lengths and were prepared from natural chrysotile. Our findings thus indicate that the diffusion rates of a wide range of natural colloidal particles can be predicted from theory, so long as the particle aspect ratio is properly taken into account. This is an important first step for understanding aggregate formation and transport of non-spherical contaminant particles, in the environment andin vivo.