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Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
17.3K
Arsenic source-sink dynamics under phosphorus competition in sediments from river-lake connected systems
Yongsheng Chang1, Wang Shuhang2, Feifei Che2
1College of Environmental Science and Engineering, Donghua University, Shanghai, 201620, China.
Environmental Science. Processes & Impacts
|February 17, 2025
Summary
Rivers are significant sources of arsenic (As) contamination to connected lakes. Sediments in river and lake regions pose a high risk for As release, influenced by phosphorus competition and microbial activity.
Area of Science:
- Environmental Chemistry
- Geochemistry
- Microbiology
Background:
- River-lake connected systems are complex environments where arsenic (As) transport and transformation are influenced by multiple factors.
- Phosphorus (P) competition significantly impacts the behavior of arsenic in sediments, affecting its release and sequestration.
- Understanding the spatial dynamics of As and P in riverine and lacustrine sediments is crucial for assessing environmental risk.
Purpose of the Study:
- To analyze arsenic (As) source and sink characteristics in sediments under phosphorus (P) competition within a river-lake connected system.
- To investigate the regionality and continuity of As release from sediments across river (R), lake (L), and lake-centre (LC) zones.
- To identify factors controlling As release, including sediment properties, P competition, and microbial community composition.
Main Methods:
- Analysis of sediment properties including oxidation-reduction potential (ORP), pH, and concentrations of As and P.
- Determination of As and P release potentials (EAsC0, EPC0) and degree of As saturation (DAsS).
- Microbial community analysis using 16S rRNA sequencing to identify dominant species and their correlation with As release.
Main Results:
- Sediments exhibited negative ORP, indicating reducing conditions. Riverine sediments were acidic, while lake-centre sediments were alkaline.
- The R region acted as a strong As source and weak P source, while the LC region was an As sink and P source. High As release risk was identified in R and L regions.
- Proteobacteria, abundant in sediments, showed a positive correlation with As release risk. Surface sediments contributed most significantly to As release, with As(V) release exceeding As(III).
Conclusions:
- Rivers are significant contributors of arsenic contamination to connected lakes, with distinct As and P dynamics across different zones.
- Sediment properties, P competition, and microbial communities (particularly Proteobacteria) play critical roles in regulating As release and sequestration.
- Management strategies should consider the spatial heterogeneity of As contamination and release risks within river-lake systems.
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