Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems

In aquatic ecosystems, microalgae experience the adverse effects of the widely used disinfectant component, polyhexamethylene guanidine (PHMG). Our research focused on the model alga, Chlorella vulgaris, examining how PHMG exposure influences its growth, photosynthesis, metabolic byproducts, and ant...

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Main Authors: Kai Zhang, Ziqin Wei, Yixuan Wang, Weikai Shui, Bingchan Jia, Zhuo Huang, Qian Feng
Format: Article
Language:English
Published: PeerJ Inc. 2025-06-01
Series:PeerJ
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Online Access:https://peerj.com/articles/19553.pdf
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author Kai Zhang
Ziqin Wei
Yixuan Wang
Weikai Shui
Bingchan Jia
Zhuo Huang
Qian Feng
author_facet Kai Zhang
Ziqin Wei
Yixuan Wang
Weikai Shui
Bingchan Jia
Zhuo Huang
Qian Feng
author_sort Kai Zhang
collection DOAJ
description In aquatic ecosystems, microalgae experience the adverse effects of the widely used disinfectant component, polyhexamethylene guanidine (PHMG). Our research focused on the model alga, Chlorella vulgaris, examining how PHMG exposure influences its growth, photosynthesis, metabolic byproducts, and antioxidant defenses. We observed a range of effects from slight disturbances at low PHMG concentrations to significant growth inhibition at higher levels, suggesting a hormesis-like response. Specifically, PHMG exposure led to reduced chlorophyll content, impaired Photosystem II efficiency, and decreased photosynthetic activity. Interestingly, the algae responded to stress by increasing antioxidant enzyme activities and stress biomarkers. Structural equation modeling (SEM) revealed that PHMG primarily disrupts the photosynthetic apparatus, which in turn affects metabolic and antioxidant responses, culminating in reduced algal biomass. Our results contribute to the understanding of the threats posed to aquatic life by the ubiquitous and ever-increasing pollution from chemical disinfectants, and highlight the urgency of mitigation measures.
format Article
id doaj-art-3b89323d7dab4139835cb7ed522ea603
institution DOAJ
issn 2167-8359
language English
publishDate 2025-06-01
publisher PeerJ Inc.
record_format Article
series PeerJ
spelling doaj-art-3b89323d7dab4139835cb7ed522ea6032025-08-20T02:39:41ZengPeerJ Inc.PeerJ2167-83592025-06-0113e1955310.7717/peerj.19553Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystemsKai Zhang0Ziqin Wei1Yixuan Wang2Weikai Shui3Bingchan Jia4Zhuo Huang5Qian Feng6Nanjing Jiangning District Water Affairs Bureau, Nanjing, ChinaNanjing No. 1 Middle School, Nanjing, ChinaHigh School Affiliated to Nanjing Normal University Jiangning Campus, Nanjing, ChinaCollege of Environment, Hohai University, Nanjing, ChinaCollege of Environment, Hohai University, Nanjing, ChinaCenter for Science and Technology Achievement Promotion, Yangtze River Scientific Research Institute, Wuhan, ChinaCollege of Environment, Hohai University, Nanjing, ChinaIn aquatic ecosystems, microalgae experience the adverse effects of the widely used disinfectant component, polyhexamethylene guanidine (PHMG). Our research focused on the model alga, Chlorella vulgaris, examining how PHMG exposure influences its growth, photosynthesis, metabolic byproducts, and antioxidant defenses. We observed a range of effects from slight disturbances at low PHMG concentrations to significant growth inhibition at higher levels, suggesting a hormesis-like response. Specifically, PHMG exposure led to reduced chlorophyll content, impaired Photosystem II efficiency, and decreased photosynthetic activity. Interestingly, the algae responded to stress by increasing antioxidant enzyme activities and stress biomarkers. Structural equation modeling (SEM) revealed that PHMG primarily disrupts the photosynthetic apparatus, which in turn affects metabolic and antioxidant responses, culminating in reduced algal biomass. Our results contribute to the understanding of the threats posed to aquatic life by the ubiquitous and ever-increasing pollution from chemical disinfectants, and highlight the urgency of mitigation measures.https://peerj.com/articles/19553.pdfPolyhexamethylene guanidine (PHMG)MicroalgaePhotosynthesisAntioxidative stressStructural equation model (SEM)
spellingShingle Kai Zhang
Ziqin Wei
Yixuan Wang
Weikai Shui
Bingchan Jia
Zhuo Huang
Qian Feng
Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
PeerJ
Polyhexamethylene guanidine (PHMG)
Microalgae
Photosynthesis
Antioxidative stress
Structural equation model (SEM)
title Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
title_full Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
title_fullStr Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
title_full_unstemmed Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
title_short Green under siege: how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
title_sort green under siege how the polyhexamethylene guanidine disinfectant attacks microalgae in aquatic ecosystems
topic Polyhexamethylene guanidine (PHMG)
Microalgae
Photosynthesis
Antioxidative stress
Structural equation model (SEM)
url https://peerj.com/articles/19553.pdf
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