The fate and transport of nanoparticles (NPs) in streams is critical for understanding their overall environmental impact. Using a unique field-scale stream at the Notre Dame-Linked Experimental Ecosystem Facility, we investigated the impact of biofilms and the presence of dissolved organic matter (DOM) on the transport of titanium dioxide (TiO₂) NPs. Experimental breakthrough curves were analyzed using temporal moments and fit using a mobile-immobile model. The presence of biofilms in the stream severely reduced the transport of the TiO₂ NPs, but this was mitigated by the presence of DOM. Under minimal biofilm conditions, the presence of DOM increased the mass recovery of TiO₂ from 4.2% to 32% for samples taken 50 m downstream. For thriving biofilm conditions only 0.5% of the TiO₂ mass was recovered (50 m), but the presence of DOM improved the mass recovery TiO₂ to 36%. The model was suitable for predicting early, peak, tail, and truncation time portions of the breakthrough curves, which attests to its ability to capture a range of processes in the mobile and immobile domains of the stream. The model outcomes supported the hypothesis that DOM changed the interaction of NP-biofilm from an irreversible to a reversible process. Collectively, these outcomes stress the importance of considering biogeological complexity when predicting the transport of NPs in streams.

纳米粒子 (NP) 在溪流中的命运和运输对于了解其整体环境影响至关重要。在圣母大学相关实验生态系统设施中使用独特的现场规模流，我们研究了生物膜和溶解有机物 (DOM) 的存在对二氧化钛 (TiO ₂ ) NP 运输的影响。使用时间矩分析实验突破曲线，并使用移动-固定模型进行拟合。流中生物膜的存在严重降低了 TiO ₂ NP 的传输，但这因 DOM 的存在而得到缓解。在最小生物膜条件下，DOM 的存在增加了 TiO _{2的质量回收}从 4.2% 到 32%，在下游 50 m 处采集的样本。对于蓬勃发展的生物膜条件，仅回收了 0.5% 的 TiO _{2质量（50 m），但 DOM 的存在将 TiO 2}的质量回收率提高到 36%。该模型适用于预测突破曲线的早期、峰值、尾部和截断时间部分，这证明了它能够捕获流的移动和固定域中的一系列过程。模型结果支持 DOM 将 NP-生物膜的相互作用从不可逆过程改变为可逆过程的假设。总的来说，这些结果强调了在预测溪流中 NP 的传输时考虑生物地质复杂性的重要性。