REVIEW article
Front. Environ. Sci.
Sec. Toxicology, Pollution and the Environment
This article is part of the Research TopicSustainable Solutions for Soil Contamination and Sludge Management: Advances in Geoenvironmental EngineeringView all articles
Research Progress on Biot-mercury Interactions in the Periphyton: Environmental Processes, Ecological Effects and Restoration Applications
Provisionally accepted
- 1College of Environmental Science and Engineering, Guilin University of Technology, Guilin, China
- 2西安水务(集团)规划设计研究院有限公司, Xian, China
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Mercury (Hg) is a pervasive global pollutant whose environmental impact is critically defined by its speciation. This review synthesizes data from 100 studies to quantify the central role of periphyton, a ubiquitous microbial-algal biofilm, in Hg sequestration and transformation. Analyses show that periphyton extracellular polymeric substances (EPS), rich in carboxyl, hydroxyl, and sulfhydryl groups, achieve rapid Hg(II) biosorption within milliseconds, with reported adsorption capacities ranging widely from 27.2 mg/g for fungal components to over 393 mg/g for specific bacterial strains. Simultaneously, the anaerobic microzones of periphyton serve as biochemical reactors where microbial guilds (e.g., sulfate-reducing bacteria and methanogens) mediate methylation via the hgcAB gene cluster and demethylation via the mer operon. A key finding consolidated from the literature is that upon senescence, this mercury-laden biomass can enhance sediment methylmercury (MeHg) concentrations by 54% to 514%, creating bioaccumulation hotspots. This review systematically dissects the adsorption mechanisms, environmental drivers, physiological adaptations, and bioremediation applications, highlighting that periphyton's dual function as a sink and source of MeHg is a pivotal, yet underexplored, dynamic in Hg cycling. We conclude by emphasizing the urgent need to couple micro-scale mechanistic understanding with watershed-level models and to develop in-situ monitoring and targated regulation strategies.
Keywords: Periphyton, Extracellular polymeric substances (EPS), Mercury, methylmercury, Adsorption mechanisms, bioremediation
Received: 27 Aug 2025; Accepted: 27 Nov 2025.
Copyright: © 2025 Li, Xu, Xu, Zhao, Miao and Zhou. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Wenyu Zhao
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