Comprehensive response of microbes to Ag and Ag2S nanoparticles and silver spatial distribution in constructed wetlands

Chong Cao; Zi Heng Ding; Juan Huang; Chun Ni Yan

doi:10.1016/j.scitotenv.2023.167683

Comprehensive response of microbes to Ag and Ag₂S nanoparticles and silver spatial distribution in constructed wetlands

Sci Total Environ. 2024 Jan 1:906:167683. doi: 10.1016/j.scitotenv.2023.167683. Epub 2023 Oct 10.

Authors

Chong Cao¹, Zi Heng Ding², Juan Huang³, Chun Ni Yan⁴

Affiliations

¹ Department of Municipal Engineering, College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China. Electronic address: ccao2@njfu.edu.cn.
² Department of Municipal Engineering, College of Civil Engineering, Nanjing Forestry University, Nanjing 210037, China.
³ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 211189, China. Electronic address: 101010942@seu.edu.cn.
⁴ Department of Municipal Engineering, School of Civil Engineering, Southeast University, Nanjing 211189, China.

PMID: 37820808
DOI: 10.1016/j.scitotenv.2023.167683

Abstract

This study investigated functional bacteria, key enzymes, and nitrogen metabolism in vertical flow constructed wetlands (CWs) after exposing to silver, silver sulfide nanoparticles (Ag NPs and Ag₂S NPs), and silver iron (Ag⁺), and silver spatial distribution in CWs for 155 days. Ag NPs and Ag₂S NPs affected species richness and diversity whereas Ag⁺ showed the higher the species diversity indices. Sequencing analysis exhibited that Ag NPs or Ag⁺ significantly inhibited nitrogen metabolic process by hindering the relative activity of functional enzymes, downregulating relative abundances of nrfA, norB and napA for Ag NPs, nxrA gene for Ag⁺, while Ag₂S NPs inhibited relative abundance of nirA. The above results confirmed that NPs or Ag⁺ significantly reduced nitrogen removal and Ag NPs mainly inhibited NO₃^--N removal while Ag⁺ significantly suppressed NH₄⁺-N removal. This study also found that CWs could effectively remove NPs or Ag⁺ (about 98 %), and nanoparticles showed higher translocation factors (TFs) values (0.81-1.15 or 0.36), indicating nanoparticles transported easily through substrate layers.

Keywords: Constructed wetlands; Functional bacteria; Nitrogen metabolism; Silver nanoparticles; Spatial distribution.

MeSH terms

Biological Transport
Metal Nanoparticles*
Nitrogen
Silver
Wetlands

Substances

Silver
Nitrogen