Phytoremediation mechanisms and plant eco-physiological response to microorganic contaminants in integrated vertical-flow constructed wetlands

Yucong Zheng; Zhuanzhuan Sun; Ying Liu; Ting Cao; Hengfeng Zhang; Mengqing Hao; Rong Chen; Mawuli Dzakpasu; Xiaochang C Wang

doi:10.1016/j.jhazmat.2021.127611

Phytoremediation mechanisms and plant eco-physiological response to microorganic contaminants in integrated vertical-flow constructed wetlands

J Hazard Mater. 2022 Feb 15;424(Pt C):127611. doi: 10.1016/j.jhazmat.2021.127611. Epub 2021 Oct 29.

Authors

Yucong Zheng¹, Zhuanzhuan Sun², Ying Liu², Ting Cao², Hengfeng Zhang², Mengqing Hao², Rong Chen³, Mawuli Dzakpasu⁴, Xiaochang C Wang³

Affiliations

¹ Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; Shaanxi Key Laboratory of Environmental Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China.
² Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China.
³ Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, PR China.
⁴ Key Laboratory of Northwest Water Resource, Environment and Ecology, MOE, School of Environmental and Municipal Engineering, Xi'an University of Architecture and Technology, Xi'an 710055, PR China; International Science & Technology Cooperation Center for Urban Alternative Water Resources Development, Xi'an University of Architecture and Technology, Xi'an 710055, PR China. Electronic address: mawuli.dzakpasu@xauat.edu.cn.

PMID: 34740163
DOI: 10.1016/j.jhazmat.2021.127611

Abstract

Vegetations play a vital role in the ecological function of constructed wetlands (CW), but the systemic phytoremediation mechanism of CW is still unclear. An integrated vertical-flow constructed wetland (IVCW) was established to elucidate the phytoremediation mechanisms and plants eco-physiological response to an emerging contaminant, sulfamethoxazole (SMX). Attenuation of SMX in IVCW with and without vegetation (Acorus calamus) are comparatively analyzed. The results showed significant enhancement of removal efficiencies of total nitrogen (via intensified denitrification) and SMX by up to 10% respectively with vegetation. A unique micro-rhizo environment was created by stimulating the denitrifiers, Clostridium_sensu_stricto, Ignavibacterium, Rhodanobacter, and Geobacter. Free-living plant growth-promoting bacteria, unclassified_Burkholderiales and unclassified_Betaproteobacteria, proliferated in the rhizosphere, protecting the growth mechanism of A. calamus and, consequently, promoting performance of the IVCW. Overall, A. calamus exhibited tolerance to SMX, maintaining its photosynthesis rate and stabilizing the plant cell structure by an effective antioxidant system. The growth and defense mechanisms of A. calamus appeared to positively correlate with the IVCW performance, whereby the photosynthetic rate and antioxidant enzymes activities peaked together with the maximum removal efficiency of TN (77.81%) and SMX (99.88%). The contribution of vegetation to ecotoxicity reduction in CW might be underrated as absorbed SMX could be phytodegraded into less toxic metabolites via specific enzymes.

Keywords: antibiotic; micro-rhizo environment; plant growth and defense mechanism, plant growth-promoting bacteria.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Biodegradation, Environmental
Nitrogen / analysis
Sulfamethoxazole
Wastewater*
Wetlands*

Substances

Waste Water
Sulfamethoxazole
Nitrogen