The need to quantify engineered nanoparticles (ENPs) in the environment is due to the increasing incorporation of these particles in the daily products, which threatens human health and can possibly impact natural systems. Ceria NPs (CeO2NPs) and titanium dioxide NPs (TiO2NPs) are two of the most used ENPs in the world. In this study their occurrence was determined in river waters with accurate and relevant techniques such as single particle ICP-MS (spICPMS). In the Loire River (France), the variation of both CeO2NPs and TiO2NPs could be assessed locally, with an increase of the concentrations near a wastewater treatment plant (WWTP) outlet as well as in a lake connected to the river and dedicated to outdoor activities. In the upstream river water, supposedly less impacted by NPs, 6.4 ± 1.2 × 104 part mL–1 Ce-bearing and 13.4 ± 1.8 × 104 part mL–1 Ti-bearing particles were measured. These values increased to 33.9 ± 3.4 × 104 part mL–1 Ce-bearing and 80.3 ± 3.4 × 104 part mL–1 Ti-bearing particles near the WWTP outlet. Equivalent size for sphere distributions ranged from 24 nm to 70 nm for CeO2 and from 80 nm to 500 nm for TiO2 in the river water. In the lake, a raise of the concentrations has been observed with 38.3 ± 2.0 × 104 part mL–1 and 71.6 ± 2.1 × 104 part mL–1 containing Ce and Ti, respectively, with similar size distributions. FEG-SEM imaging confirms the occurrence of Ce- and Ti-bearing particles in the water samples. On the contrary, NPs seem to undergo strong heteroaggregation in the Loire river water. The Ce/La elemental ratios does not evolve from upstream to downstream the WWTP outlet, suggesting that a natural origin cannot be excluded to explain the increase observed in NPs number concentration. On the contrary, the Ce/La ratio increases in the outdoor activities center, which suggests the contribution of NPs potentially related to the cars parked nearby. Besides, elemental ratios Ti/V and Ti/Y have been assessed to highlight an anthropogenic source of Ti in both sampling sites, possibly to the sunscreens used during the summer.

中文翻译：

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通过单粒子 ICP-MS 和 FEG-SEM 成像在卢瓦尔河（法国）中二氧化铈和二氧化钛纳米粒子的发生和起源

需要对环境中的工程纳米粒子 (ENP) 进行量化是由于这些粒子越来越多地融入日常产品中，这威胁着人类健康并可能影响自然系统。Ceria NPs (CeO2NPs) 和二氧化钛 NPs (TiO2NPs) 是世界上使用最多的两种 ENP。在这项研究中，使用准确且相关的技术（例如单粒子 ICP-MS (spICPMS)）确定了它们在河水中的存在。在卢瓦尔河（法国），CeO2NPs 和 TiO2NPs 的变化可以在当地进行评估，污水处理厂 (WWTP) 出口附近以及与河流相连并专门用于户外活动的湖泊中的浓度增加. 在上游河水中，据推测受 NPs 的影响较小，6.4 ± 1.2 × 104 部分 mL–1 含 Ce 和 13.4 ± 1。测量了 8 × 104 份 mL-1 含钛颗粒。在污水处理厂出口附近，这些值增加到 33.9 ± 3.4 × 104 份 mL-1 含 Ce 颗粒和 80.3 ± 3.4 × 104 份 mL-1 含 Ti 颗粒。球体分布的等效尺寸范围为 CeO2 的 24 nm 至 70 nm，河水中的 TiO2 的等效尺寸范围为 80 nm 至 500 nm。在湖中，观察到浓度升高，分别含有 38.3 ± 2.0 × 104 份 mL-1 和 71.6 ± 2.1 × 104 份 mL-1 的 Ce 和 Ti，具有相似的尺寸分布。FEG-SEM 成像证实了水样中存在含 Ce 和 Ti 的颗粒。相反，NPs 似乎在卢瓦尔河水中经历了强烈的异质聚集。Ce/La 元素比率不会从 WWTP 出口的上游到下游演变，表明不能排除天然来源来解释观察到的 NPs 数量浓度的增加。相反，户外活动中心的 Ce/La 比率增加，这表明 NP 的贡献可能与附近停放的汽车有关。此外，已评估元素比率 Ti/V 和 Ti/Y，以突出两个采样点的人为 Ti 来源，可能与夏季使用的防晒霜有关。