The recent expansion in the use of nanomaterials in consumer and industrial applications has led to a growing concern over their behavior, fate, and impacts in environmental systems. However, engineered nanoparticles comprise only a small fraction of the total nanoparticle mass in aquatic systems. Human activities, particularly in urban watersheds, are increasing the population of incidental nanoparticles and are likely altering the cycling of more abundant natural nanoparticles. Accurate detection, quantification, characterization, and tracking of these different populations is important for assessing both the ecological risks of anthropogenic particles, and their impact on environmental health. The urban portion of the South Platte watershed in Denver, Colorado (United States) was sampled for zinc to identify and quantify different nanomaterial sources. Single particle ICP-QMS was employed, to provide single elemental (Zn) signals arising from particle detection events. Coupling spICP-QMS to sample pre-fractionation (sedimentation, filtration) provided some insights into Zn association with nanoparticulate, colloidal, and suspended sediment phases. Single particle ICP-TOFMS (spICP-TOFMS) provided quantification across a large atomic mass range, yielding an even more detailed characterization (elemental ratios) on a particle-by-particle basis, providing some delineation of multiple sources of particles. Across the watershed, on average, 21% of zinc mass was present as zinc-only particles with a rather uniform mean size of 40.2 nm. Zinc that was detected with one or more other elements, primarily Al, Fe, and Si, is likely to be present as heteroagglomerates or within mineral colloids. Although spICP-TOFMS provides a substantial amount of information, it is still in its early stages as an analytical technique and currently lacks the requisite sensitivity to study the smallest of nanoparticles. As this technique continues to develop, it is anticipated that this methodology can be broadly applied to study sources, behavior and effects of a disparate variety of nanoparticles from both geogenic and anthropogenic origins.

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城市流域中纳米颗粒锌的定量和表征

最近纳米材料在消费和工业应用中的使用扩大，导致人们越来越关注它们的行为、命运和对环境系统的影响。然而，工程纳米粒子仅占水生系统中纳米粒子总质量的一小部分。人类活动，特别是在城市流域，正在增加偶然出现的纳米粒子的数量，并可能改变更丰富的天然纳米粒子的循环。准确检测、量化、表征和跟踪这些不同的种群对于评估人为颗粒的生态风险及其对环境健康的影响非常重要。丹佛南普拉特流域的城市部分，科罗拉多州（美国）采样了锌，以识别和量化不同的纳米材料来源。采用单颗粒 ICP-QMS 来提供由颗粒检测事件产生的单元素 (Zn) 信号。将 spICP-QMS 与样品预分馏（沉淀、过滤）相结合，可以深入了解 Zn 与纳米颗粒、胶体和悬浮沉积物相的结合。单粒子 ICP-TOFMS (spICP-TOFMS) 提供了大原子质量范围内的量化，在逐个粒子的基础上产生了更详细的表征（元素比），提供了对多个粒子来源的一些描述。在整个分水岭，平均 21% 的锌质量以纯锌颗粒的形式存在，平均尺寸相当均匀，为 40.2 nm。与一种或多种其他元素一起检测到的锌，主要是 Al、Fe 和 Si，可能以杂团聚体或矿物胶体的形式存在。尽管 spICP-TOFMS 提供了大量信息，但它作为一种分析技术仍处于早期阶段，目前缺乏研究最小纳米颗粒所需的灵敏度。随着这项技术的不断发展，预计这种方法可以广泛应用于研究来自地质和人为起源的不同种类纳米粒子的来源、行为和影响。