Department of Municipal Engineering, School of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China; Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 211189, China.
Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 211189, China.
J Hazard Mater. 2022 Jun 15;432:128642. doi: 10.1016/j.jhazmat.2022.128642. Epub 2022 Mar 8.
Constructed wetlands (CWs) are environmentally friendly engineered systems to purify wastewater, with low-cost and easy maintenance. However, it is not clear on responses of functional microbes for nitrogen (N) and phosphorus (P) biotransformation in CWs to silver nanoparticles (Ag NPs). The high throughput sequencings were employed to reveal microbial communities in vertical flow subsurface CWs with stable operation for 120 days. The results indicated that NH-N, TN and TP removal of soil layer decreased by 43.56%, 15.7% and 22.7% under stress of Ag NPs. Microbial richness index and compositions were affected, and control wetland enriched Sulfurospirillum, Desulfarculaceae and Flavobacterium whereas CWs exposed to Ag NPs enriched Desulfosporosinus and Desulfurispora from LEfSe analysis. Moreover, after dosing Ag NPs, relative abundances of functional genes amoA and hao for nitrification, nirK and norB for denitrification and ppx and phoA/phoD for phosphorus conversions in upper soil were significantly downregulated. Inhibition on functional bacteria and genes of Ag NPs explained poor removal efficiencies of nitrogen and phosphorus pollutants in CWs. Our findings give an insight into ecological toxicity of Ag NPs on CWs with N and P bioconversions and provide the understanding of response of nitrifiers, denitrifies and PAOs.
人工湿地（CWs）是一种环保型工程系统，用于净化废水，具有低成本和易于维护的特点。然而，目前还不清楚 CWs 中功能微生物对氮（N）和磷（P）生物转化的响应情况。本研究采用高通量测序技术，揭示了垂直流地下 CWs 中微生物群落的变化，该 CWs 稳定运行了 120 天。结果表明，在 Ag NPs 的胁迫下，土壤层中 NH-N、TN 和 TP 的去除率分别下降了 43.56%、15.7%和 22.7%。微生物丰富度指数和组成受到影响，对照组湿地富集了 Sulfurospirillum、Desulfarculaceae 和 Flavobacterium，而暴露于 Ag NPs 的 CWs 则从 LEfSe 分析中富集了 Desulfosporosinus 和 Desulfurispora。此外，投加 Ag NPs 后，上壤中硝化功能基因 amoA 和 hao、反硝化功能基因 nirK 和 norB 以及磷转化功能基因 ppx 和 phoA/phoD 的相对丰度均显著下调。Ag NPs 对功能细菌和基因的抑制解释了 CWs 中氮和磷污染物去除效率差的原因。本研究结果深入了解了 Ag NPs 对 CWs 中氮和磷生物转化的生态毒性，并为硝化菌、反硝化菌和 PAOs 的响应提供了认识。
