Addressing lake eutrophication requires controlling external phosphorus inputs from sources such as agricultural runoff and domestic wastewater, while also paying attention to phosphorus that has accumulated in lake sediments. When the mechanisms that immobilize phosphorus in sediments change, previously retained phosphorus may be released back into the water, contributing to a persistent internal phosphorus load.
When do sediments shift from retaining phosphorus to releasing it? A research team comprising the Chinese Research Academy of Environmental Sciences and other institutions investigated sediments from Lake Qilu in Yunnan, China. The team combined multiple techniques, including elemental analysis, diffusive gradients in thin films (DGT), stable isotope analysis, and SEM-EDS, to examine geochemical processes involving iron, sulfur, and phosphorus (Fe–S–P) from different perspectives. Quantitative measurement of key elements, including Fe and Al, provided important data for establishing environmental parameters and conducting subsequent mechanistic analyses. For this part of the study, the research team used the SUPEC 7000 Inductively Coupled Plasma Mass Spectrometry (ICP-MS) developed by EXPEC Technology, an FPI subsidiary.
The study found that when the ratio of reactive dissolved organic carbon (rDOC) to reactive iron exceeded 8.04, the stability of the iron-mediated phosphorus sink in sediments declined significantly. The findings were published online on July 30, 2026, in Water Research, an international journal in environmental science with a 2025 Journal Citation Reports (JCR) impact factor of 12.8.
The research findings were published online in Water Research on July 30, 2026.
How should this threshold be interpreted?
- 8.04 is a ratio threshold for rDOC to reactive Fe, not a concentration threshold for any single element.
- The threshold is influenced by a lake’s long-term sedimentation and mineral accumulation history; it is not a fixed constant applicable to all lakes.
- The finding links organic matter inputs and changes in reactive iron to the stability of phosphorus retention in sediments, offering a new perspective on the mechanisms behind internal phosphorus release in lakes.
Graphical abstract from: Liu, Y., et al. (2026). Reactive organic matter destabilizes Fe-mediated phosphorus retention through Fe-S-P decoupling in lake sediments. Water Research, 306, 126597. https://doi.org/10.1016/j.watres.2026.126597
© 2026 Elsevier Ltd. All rights reserved.
In this study, SUPEC 7000 was used to obtain quantitative data on key elements. The identification of the critical threshold, however, relied on the combined evidence of multiple experimental datasets, parameter calculations, and statistical analyses. The SUPEC 7000 ICP-MS offers high sensitivity, low detection limits, excellent stability, and a wide dynamic linear range. It can be used for quantitative analysis of samples across various matrices, including soil, food, and environmental samples.
EXPEC Technology’s ICP-MS was used in research conducted by a research team involving the Chinese Research Academy of Environmental Sciences and other institutions. The findings were published in Water Research.
From quantitative analysis of key elements to environmental parameter development and mechanistic investigation, FPI continues to support environmental science research with analytical instrumentation and data acquisition capabilities.
Read the Original Article: https://www.sciencedirect.com/science/article/abs/pii/S0043135426012716?utm_source
Reference: Liu, Y., et al. (2026). Reactive organic matter destabilizes Fe-mediated phosphorus retention through Fe-S-P decoupling in lake sediments. Water Research, 306, 126597. https://doi.org/10.1016/j.watres.2026.126597
