Sediment resuspension causes horizontal variations in the distributions of phosphorus (P) and P-inactivating materials with differing P immobilization in different sediment planes

Xinyi Shen; Wei Li; Bo Fan; Chenghao Huang; Leilei Bai; Helong Jiang; Huacheng Xu; Changhui Wang

doi:10.1016/j.watres.2023.120327

Sediment resuspension causes horizontal variations in the distributions of phosphorus (P) and P-inactivating materials with differing P immobilization in different sediment planes

Water Res. 2023 Sep 1:243:120327. doi: 10.1016/j.watres.2023.120327. Epub 2023 Jul 8.

Authors

Xinyi Shen¹, Wei Li², Bo Fan³, Chenghao Huang¹, Leilei Bai², Helong Jiang², Huacheng Xu², Changhui Wang⁴

Affiliations

¹ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; Graduate University of Chinese Academy of Sciences, Beijing 100049, China.
² State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
³ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China; College of Biology and Environment, Nanjing Forestry University, Nanjing 210037, China.
⁴ State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China. Electronic address: chwang@niglas.ac.cn.

PMID: 37451125
DOI: 10.1016/j.watres.2023.120327

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.

Keywords: Drinking water treatment residuals; Geoengineering; Internal phosphorus loading; Lake restoration.

MeSH terms

Eutrophication
Geologic Sediments
Lakes
Phosphorus*
Water Pollutants, Chemical* / analysis

Substances

Phosphorus
Water Pollutants, Chemical