Titanium dioxide nanoparticles (TiO₂ NPs) have been widely used in industrial and commercial products, resulting in potential environmental risks. However, the impacts of these nanoparticles on wastewater treatment in ecological systems are less known. In this study, short- and long-term effects of TiO₂ NPs on contaminant removal in constructed wetlands (CWs) were investigated. The results showed that short-term exposure to TiO₂ NPs (1 and 50 mg/L) induced marginal adverse effects on treatment performance (COD, TN, NH₄⁺-N, and TP) of CWs, while N removal evidently declined under prolonged exposure to TiO₂ NPs. Furthermore, metagenomics and enzyme activities analyses suggested that the reduced N removal efficiency could possibly be due to the decrease in the relative abundance of nitrifiers (Nitrospira and Nitrosomonas) and inhibition of ammonia monooxygenase activity. In contrast, long-term exposure to TiO₂ NPs promoted net photosynthesis rate, stomatal conductance, transpiration rate and root activity of Phragmites australis, indicating a positive impact of TiO₂ NPs on plant physiology. Overall, the findings of this study suggested that long-term exposure to TiO₂ NPs at an environmentally relevant concentration (1 mg/L) significantly altered the functionalities of microorganisms and plants, which in turn impaired the wastewater treatment performance of CWs.

二氧化钛纳米颗粒（TiO ₂ NPs）已广泛用于工业和商业产品中，导致潜在的环境风险。但是，这些纳米颗粒对生态系统废水处理的影响尚不为人所知。在这项研究中，研究了TiO ₂ NPs对人工湿地（CWs）污染物去除的短期和长期影响。结果表明，短期暴露于TiO ₂ NPs（1和50 mg / L ）对CW的处理性能（COD，TN，NH ₄ ⁺ -N和TP）产生了一定程度的不利影响，而在以下条件下，N的去除明显降低了长时间暴露于TiO ₂NP。此外，宏基因组学和酶活性分析表明，氮去除效率的降低可能是由于硝化剂（硝化螺菌和亚硝化单胞菌）的相对丰度的降低以及氨单加氧酶活性的抑制所致。相反，长期暴露于TiO ₂ NPs可以促进芦苇的净光合速率，气孔导度，蒸腾速率和根系活动，这表明TiO ₂ NPs对植物生理有积极影响。总体而言，这项研究的结果表明，长期暴露于TiO ₂ 与环境有关的浓度（1 mg / L）的NPs显着改变了微生物和植物的功能，进而损害了CW的废水处理性能。