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Updated: Apr 11, 2026
10:49
Laboratory-determined Phosphorus Flux from Lake Sediments as a Measure of Internal Phosphorus Loading
Published on: March 6, 2014
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Internal phosphorus load in a Mexican reservoir: forecast and validation
Anne M Hansen1, Henri Márquez-Pacheco1
1Mexican Institute of Water Technology, Hydrology Jiutepec, Morelos, Mexico.
Environmental Toxicology and Chemistry
|June 11, 2015
Summary
Internal phosphorus load (IPL) in a Mexican reservoir can be determined by analyzing redox potential (Eh) in sediments. This method aligns with mass balance and sediment core analyses, identifying peak IPL during summer stratification.
Area of Science:
- Environmental Science
- Limnology
- Geochemistry
Background:
- Phosphorus (P) internal load (IPL) is a critical factor in reservoir eutrophication.
- Understanding IPL dynamics is essential for effective water resource management.
- Redox potential (Eh) in sediments significantly influences P release.
Purpose of the Study:
- To determine the internal phosphorus load (IPL) as a function of redox potential (Eh) in a Mexican reservoir.
- To compare IPL estimations using different methodologies: Eh-based, mass balance (MB), and sediment cores (SC).
- To identify seasonal patterns of IPL and their correlation with reservoir stratification.
Main Methods:
- Extrapolation of P release experiment results to temporal and spatial Eh variations in sediments.
- Calculation of P mass balance (MB) by quantifying P inputs and outputs.
- Analysis of P concentrations in sediment cores (SCs) to determine historical P release.
Main Results:
- An IPL derived from Eh (IPL-Eh) was calculated as 24.2 ± 2.5 t/yr.
- IPL estimated via mass balance (IPL-MB) was 26.4 ± 4.9 t/yr.
- IPL estimated from sediment cores (IPL-SC) was 23.5 ± 1.4 t/yr.
- All three IPL estimation methods yielded similar results, with average values within the standard deviation of IPL-MB.
- Peak IPL was observed from May to August, coinciding with thermal stratification of the water column.
Conclusions:
- Analysis of redox potential (Eh) variations in sediments is a reliable method for determining a reservoir's internal phosphorus load (IPL).
- The consistency across different IPL assessment methods (Eh, MB, SC) strengthens the findings.
- Internal phosphorus loading is exacerbated during periods of thermal stratification, highlighting a key vulnerability in reservoir ecosystems.
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