Effect and mechanism of silver nanoparticles on nitrogen transformation in water-sediment system of a hypereutrophic lake.
Effect and mechanism of silver nanoparticles on nitrogen transformation in water-sediment system of a hypereutrophic lake.
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DOI：
10.1016/j.scitotenv.2020.144182
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发表时间：
2020-12
期刊：
影响因子：
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通讯作者：
S. Bao;Jian Xu;Wei Tang;T. Fang
中科院分区：
文献类型：
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作者：
S. Bao;Jian Xu;Wei Tang;T. Fang
工业化和城市化预计将增加银纳米颗粒（AgNPs）释放到水生生态系统。然而，它仍然是有待确定的银纳米粒子如何影响氮转化和自然水体中的潜在机制。本文研究了银纳米颗粒对富营养化湖泊水-沉积物系统中氮循环的影响，并从氮功能酶和基因的角度探讨了氮转化的机制。连续7 d的微宇宙试验结果表明，50 mg/L Ag+处理显著提高了底泥中总氮（TN）和有机氮（OrgsinglebondN）的含量（P< 0.05）。相反，AgNPs处理（0.5和50 mg/L）的TN和Org-N水平均略有下降。此外，AgNPs的存在显著降低了NO3−-N的水平（P< 0.05）。此外，我们的数据证明，酶和那些酶编码基因参与氮转化可能直接负责氮转化的变化。总体而言，我们的工作表明，短期暴露于AgNPs可能会导致激素效应的氮转化微生物在过度富营养化的湖泊，并有可能导致在过度富营养化的湖泊氮循环的不可忽视的变化。
Industrialization and urbanization are expected to increase the release of silver nanoparticles (AgNPs) into aquatic ecosystems. However, it remains to be determined how AgNPs influence nitrogen transformation and the underlying mechanism in natural water bodies. Here, the impact of AgNPs on nitrogen cycling in water-sediment system of a hypereutrophic lake was studied and the mechanism of nitrogen transformation was investigated in terms of the nitrogen functional enzymes and genes. Following 7 days of water-sediment microcosm experiments, the levels of total nitroten (TN) and organic nitrogen (Orgsingle bondN) were significantly increased by 50 mg/L Ag+treatment when compared with the non-Ag control (P< 0.05). In contrast, the levels of TN and Org-N were both slightly decreased by AgNPs treatments (0.5 and 50 mg/L). Additionally, the levels of NO3−-N were evidently reduced with the presence of AgNPs (P< 0.05). Further, our data proved that enzymes and those enzyme encoding genes involved in the nitrogen transformation may directly responsible for the alterations of nitrogen transformation. Overall, our work suggested that the short-term exposure to AgNPs might cause hormetic effects on nitrogen-transforming microorganisms in hypereutrophic lakes, and have a potential to result in non-negligible changes in the nitrogen cycling of hypereutrophic lakes.