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Li Q, Yan W, Li M, Chen X, Wu T, He X, Yao Q, Yan Y, Li G. Simultaneous immobilization of sediment internal phosphorus, arsenic and tungsten by lanthanum carbonate capping. Environ Res 2024; 242:117817. [PMID: 38043892 DOI: 10.1016/j.envres.2023.117817] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2023] [Revised: 11/26/2023] [Accepted: 11/27/2023] [Indexed: 12/05/2023]
Abstract
In this study, lanthanum carbonate (LC) was selected as a capping agent to examine its effectiveness in immobilizing sediment internal phosphorus (P), arsenic (As) and tungsten (W). With a 180-day incubation experiment, it was determined that LC capping efficiently reduced the concentrations of soluble reactive P (SRP), soluble As and soluble W in pore water, with the highest reduction rate of 83.39%, 56.21% and 68.52%, respectively. The primary mechanisms involved in the adsorption of P, As and W by LC were precipitation reactions and ligand exchange. Additionally, P, As and W were immobilized by LC capping through the transformation of fractions from mobile and less stable forms to more stable forms. Furthermore, LC capping led to an increase in the Eh value, which promoted the oxidation of soluble Fe (Ⅱ) and soluble Mn. The significantly positive correlation and synchronized variations observed between SRP, soluble As, soluble W, and soluble Fe (II) indicated that the effects of LC on Fe redox played a crucial role in immobilizing sediment internal P, As and W. However, the oxidation of Mn, promoted by LC, played a more significant role in immobilizing sediment internal As than P and W. These effects resulted in LC capping achieving the highest reduction of SRP, soluble As and soluble W flux at 145.22, 22.19, and 0.58 μg m-2d-1. It is of note that LC capping did not lead to an elevated release hazard of Co, Ni, Cu, and Pb, barring Cd. Besides, LC capping did not modify the entire microbial communities in the sediment, but altered the proportional representation of specific microorganisms. Generally, LC has potential as a capping agent capable of simultaneously immobilizing sediment internal P, As and W.
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Affiliation(s)
- Qi Li
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China; National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, 210098, China
| | - Wenming Yan
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China; National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, 210098, China.
| | - Minjuan Li
- National Key Laboratory of Water Disaster Prevention, Hohai University, Nanjing, 210098, China
| | - Xiang Chen
- Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment, Nanjing, 210042, China
| | - Tingfeng Wu
- . State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, 210008, China
| | - Xiangyu He
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China
| | - Qi Yao
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China
| | - Yulin Yan
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China
| | - Gaoxiang Li
- College of Hydrology and Water Resources, Hohai University, Nanjing, 210098, China
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