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Updated: May 28, 2026
06:52
Experimental Column Setup for Studying Anaerobic Biogeochemical Interactions Between Iron (Oxy)Hydroxides, Trace Elements, and Bacteria
Published on: December 19, 2017
Iron-Containing Flocs Derived from Environmental Emergency Response Influenced Nitrogen Cycling Driven by
Zeqiang Huang1, Sili Chen2, An Fan1
1School of Civil Engineering, University of South China, Hengyang 421001, China.
Microorganisms
|May 27, 2026
Summary
Excessive iron-based coagulants used for metal spill cleanup can harm river sediment microbes, particularly nitrogen cycling. Ferric chloride flocs showed the most negative impact, highlighting the need to limit coagulant use in emergencies.
Area of Science:
- Environmental Science
- Microbiology
- Ecotoxicology
Background:
- In situ coagulation is a common emergency response to metal spills.
- Overuse of iron-based coagulants may cause secondary ecological impacts on river sediments.
- The specific effects of coagulant flocs on sediment microbial communities are not well understood.
Purpose of the Study:
- To investigate the impact of flocs from polymeric ferric sulfate (PFS), polymeric ferric chloride (PFC), and ferric chloride (FeCl3) on sediment microbial communities.
- To elucidate the effects on nitrogen cycling processes and microbial diversity.
- To determine coagulant-specific ecological impacts.
Main Methods:
- Microcosm experiments using iron-based coagulant flocs and river sediment.
- Metagenomics and quantitative PCR to analyze microbial community structure and function.
- Determination of ammonia oxidation potential to assess nitrogen cycling activity.
Main Results:
- Coagulant flocs significantly altered sediment microbial community structure and nitrogen cycling.
- Ferric chloride (FeCl3) flocs caused the greatest reduction in microbial diversity and ammonia oxidation potential.
- Ammonia-oxidizing archaea (AOA) were more sensitive to iron flocs than ammonia-oxidizing bacteria (AOB); PFS flocs reduced nitrate reduction genes.
Conclusions:
- The pre-polymerization state of inorganic coagulants significantly influences their ecological effects.
- Coagulant flocs alone, without metal contaminants, can negatively impact sediment nitrogen cycling.
- Limiting coagulant dosage in emergency responses is crucial to mitigate secondary environmental damage.
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