1. Sediment resuspension causes horizontal variations in the distributions of phosphorus (P) and P-inactivating materials with differing P immobilization in different sediment planes.
- Author
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Shen X, Li W, Fan B, Huang C, Bai L, Jiang H, Xu H, and Wang C
- Subjects
- Geologic Sediments, Eutrophication, Lakes, Phosphorus, Water Pollutants, Chemical analysis
- Abstract
The importance of controlling internal phosphorus (P) pollution in lakes has been recognized by scientists, and the application of P-inactivating materials to immobilize sediment P is often considered. However, sediment resuspension, a typical physical process occurring in lakes, has been demonstrated to increase the uncertainty of immobilization. In this study, we explored the characteristics of P immobilization in the horizontal direction under the effects of resuspension using annular flume tests based on drinking water treatment residuals (DWTR). The results showed that resuspension caused the mobile P and bioavailable P to be heterogeneously distributed in sediment planes after DWTR addition, resulting in varying P immobilization efficiencies at different depths. In particular, the coefficient of variation was 14.2-24.5% for mobile P horizontally distributed in the planes, resulting in a range of mobile P decreasing efficiencies at 24.0-47.8%. Further analysis indicated that variations in horizontal distribution were typically due to the varied migration of particles of different sizes. Specifically, P immobilization in sediment planes at different depths was regulated by promoting the migration of <8 μm DWTR after relatively low-intensity disturbance (in surface 0-1 cm sediment). After relatively high-intensity disturbance (in the whole 0-3 cm sediment), immobilization in the horizontal direction was regulated by coupling the migration of >63 μm DWTR (to the bottom) with the mixing of <8 μm DWTR in the sediment plane at different depths. The varying horizontal distributions of total P, resulting from the migration of 16-32 μm sediment, could enhance the heterogeneities of the P immobilization. Thus, the particle size of materials and lake background conditions, for example, the hydrodynamic characteristics and P distributions in differently sized sediments, should be used as key bases to select or develop P-inactivating materials to design proper remediation strategies for controlling internal P pollution in lakes., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)
- Published
- 2023
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