Triclosan disturbs nitrogen removal in constructed wetlands: Responses of microbial structure and functions

Qingqing Pang; Lei Xie; Caofeng Shen; Xiang Zhu; Longmian Wang; Lixiao Ni; Fuquan Peng; Jianghua Yu; Ling Wang; Fei He

doi:10.1016/j.envres.2023.117847

Triclosan disturbs nitrogen removal in constructed wetlands: Responses of microbial structure and functions

Environ Res. 2024 Feb 15:243:117847. doi: 10.1016/j.envres.2023.117847. Epub 2023 Dec 6.

Authors

Qingqing Pang¹, Lei Xie², Caofeng Shen³, Xiang Zhu³, Longmian Wang⁴, Lixiao Ni⁵, Fuquan Peng¹, Jianghua Yu⁶, Ling Wang⁷, Fei He⁸

Affiliations

¹ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China.
² Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China; Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
³ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China; College of Environment, Hohai University, Nanjing, 210098, China.
⁴ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China. Electronic address: wlmian@sina.com.
⁵ College of Environment, Hohai University, Nanjing, 210098, China.
⁶ Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, Nanjing, 210044, China.
⁷ Xinjiang Tianxi Environmental Protection Technology Co., LTD., Urumqi, 830000, China.
⁸ Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China. Electronic address: hefei@nies.org.

PMID: 38065393
DOI: 10.1016/j.envres.2023.117847

Abstract

This study investigated the influence of wetland types (vertical and tidal flow constructed wetlands [CWs] [VFCW and TFCW, respectively]) and concentrations of triclosan (TCS) on the removal of pollutants (TCS and nitrogen) and microbial characteristics. The efficiency of TCS removal was significantly higher with 5 μg/L TCS (Phase B) than with 30 μg/L (Phase C) in the two CWs. The efficiencies of removal of NH₄⁺-N and NO₃^--N were significantly inhibited in Phase C. Compared with the VFCW, the TFCW removed more NH₄⁺-N at the same concentration of TCS, whereas less NO₃^--N was removed, and it even accumulated. Saccharimondales, an important functional genus with the highest abundance and more node connections with other genera, had a sharp decrease in relative abundance as the increasing concentrations of TCS of the two CWs conformed with its relative abundance and significantly negatively correlated with the concentration of TCS. Differentiated Roseobacter_Clade_CHAB-I-5_Lineage and Sphaerotilus were enriched in the VFCW and TFCW, respectively. The abundance of enzymes that catalyzed nitritation was significantly inhibited by TCS, whereas nitrate reductase (EC 1.7.99.4) catalyzed both denitrification and dissimilatory nitrate reduction to ammonium (DNRA), and nitrite reductase (NADH) (EC 1.7.1.15) that catalyzed DNRA comprised a larger proportion in the two CWs. Simultaneously, the abundances of two enzymes were higher in the TFCW than in the VFCW. The network analysis indicated that the main genera were promoted more by TCS in the VFCW, while inhibited in the TFCW. Moreover, the concentrations of nitrogen (NH₄⁺-N, NO₃^--N, and TN) significantly positively correlated with TCS-resistant bacteria, and negatively correlated with most nitrogen-transforming bacteria with species that varied between the VFCW and TFCW. The results of this study provide a reference for the molecular biological mechanism of the simultaneous removal of nitrogen and TCS in the CWs.

Keywords: Nitrogen metabolism; Nitrogen-transforming functional bacteria; Triclosan; Triclosan-resistant bacteria; Vertical and tidal flow CWs.

MeSH terms

Bacteria
Denitrification*
Nitrates
Nitrogen
Triclosan*
Waste Disposal, Fluid / methods
Wetlands

Substances

Triclosan
Nitrogen
Nitrates