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Wang F, Wang C, Zheng Y, Li X, Qin H, Ding W. Estimating nitrogen fates and gross transformations in bioretention systems with applications of 15N labeling methods. Chemosphere 2021; 270:129462. [PMID: 33418215 DOI: 10.1016/j.chemosphere.2020.129462] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [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: 05/14/2020] [Revised: 12/19/2020] [Accepted: 12/25/2020] [Indexed: 06/12/2023]
Abstract
Two batches of 15NH4+ and 15NO3- labeling experiments were conducted to understand the complex nitrogen (N) fates and transformations in bioretention systems, respectively. The fates of 15NH4+ were first traced in six bioretention systems with different wet-dry regimes and submerged zone settings during four months, indicating: (1) 15N was mainly leached during the second storm events following the 15NH4+ addition during the first storm events, suggesting nitrification during the dry period; (2) the main 15NH4+ fates after four-month exposure were: soil media 59.6%-80.0%, outflow 5.3%-16.4%, plants 2.3%-8.9%, denitrification losses 0-28.4%; (3) longer antecedent dry weather period and submerged zone could help alleviate outflow NO3- leaching. The occurrence time, positions and rates of major N transformation processes were later examined by the 15NO3- labeling experiment in a bioretention system over an 8 d wet-dry cycle, indicating: (1) during the brief wet period, hydraulic mixing of "old" water and "new" inflow mainly occurred; (2) during the subsequent dry period, gross rates of nitrification, denitrification and mineralization showed "pulse effects", i.e. peaking at 24-48 h and decreasing significantly within 72 h; (3) denitrification became more dynamic with soil media depth, especially in submerged zone. This study evidenced the feasibility of 15N labelling method in studying N dynamics in bioretention systems and would inform future engineering and stormwater management practices.
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Affiliation(s)
- Fan Wang
- School of Atmospheric Sciences, Sun Yat-sen University, Key Laboratory for Tropical Atmosphere-Ocean System, Ministry of Education, Zhuhai, 519082, China; Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055, Shenzhen, China; Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai 519000, China
| | - Chuansheng Wang
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055, Shenzhen, China; Department of Civil and Environmental Engineering, National University of Singapore, 1 Engineering Drive 3, Singapore, 117580, Singapore
| | - Yanyan Zheng
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055, Shenzhen, China
| | - Xiaoyue Li
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055, Shenzhen, China
| | - Huapeng Qin
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055, Shenzhen, China.
| | - Wei Ding
- Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking University Shenzhen Graduate School, 518055, Shenzhen, China
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