Several industries manufacture and process large quantities of engineered nanomaterials, thus increasing the potential for their environmental release during waste management and disposal. Herein, we quantified the release and spatial distribution of titanium dioxide nanomaterials (TiO2 NMs) emitted from an industrial waste stream that flows into a nearby river. Two sampling campaigns were carried out on the river in fall 2017 and spring 2018 at selected sites upstream and downstream of the Industrial Effluent and an urban wastewater treatment plant (WWTP). Significant Ti accumulation was detected in the sediments at the Industrial Effluent and WWTP sites for both fall and spring samples, with measured Ti concentrations of 75–193 mg Ti/kg reaching 21–55× that of the local background upstream. X-ray diffraction analysis confirmed the anatase and rutile mineralogy of the inputs. River surface waters were filtered on-site to distinguish between particulate (>0.20 μm), colloidal (0.02–0.20 μm), and dissolved and/or small nanoparticulate (NP) (<0.02 μm) TiO2. Up to 133 and 260 μg Ti/L were measured in the unfiltered waters for the Industrial Effluent and WWTP fall samples, respectively, while the spring samples exhibited Ti concentrations similar to the background concentration. Combining chemical analysis and scanning electron microscopy revealed that some Ti particles recovered from the Industrial Effluent and WWTP were clusters of TiO2 NMs (~50 nm). Furthermore, anthropogenic TiO2 was distinguished apart from natural Ti-containing minerals by comparing the concentration ratios between Ti and other naturally occurring elements (e.g., V, Al, and Fe). This study confirmed the release of manufactured TiO2 NMs from the Industrial Effluent and the WWTP into the river, finding that almost all of the TiO2 NMs are released in the particulate fraction (>0.20 μm), and that the particles sediment rapidly near the emission source and accumulate in the sediment.

中文翻译：

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纳米材料制造商工业场地下游河流中二氧化钛颗粒的人为释放和分布

一些行业制造和加工大量工程纳米材料，从而增加了在废物管理和处置过程中释放环境的可能性。在此，我们量化了从流入附近河流的工业废物流中排放的二氧化钛纳米材料 (TiO2 NMs) 的释放和空间分布。2017 年秋季和 2018 年春季，在工业污水上游和下游的选定地点和城市污水处理厂 (WWTP) 上对河流进行了两次采样活动。对于秋季和春季样品，在工业废水和污水处理厂站点的沉积物中检测到显着的 Ti 积累，测得的 Ti 浓度为 75–193 mg Ti/kg，达到上游当地背景浓度的 21–55 倍。X 射线衍射分析证实了输入的锐钛矿和金红石矿物学。河表水在现场进行过滤，以区分颗粒 (>0.20 μm)、胶体 (0.02–0.20 μm) 和溶解和/或小纳米颗粒 (NP) (<0.02 μm) TiO2。工业废水和污水处理厂秋季样品的未过滤水中的 Ti/L 分别高达 133 和 260 μg，而春季样品的 Ti 浓度与背景浓度相似。结合化学分析和扫描电子显微镜显示，从工业废水和污水处理厂中回收的一些 Ti 颗粒是 TiO2 NMs（~50 nm）簇。此外，通过比较 Ti 与其他天然存在的元素（例如 、V、Al 和 Fe）。本研究证实了工业废水和污水处理厂制造的 TiO2 NMs 释放到河流中，发现几乎所有的 TiO2 NMs 都以颗粒部分 (>0.20 μm) 形式释放，并且颗粒在排放源附近迅速沉积并在沉积物中堆积。