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Li Y, Wang Z, Cai Y, Xiao K, Guo Z, Pan F. High resolution dissolved heavy metals in sediment porewater of a small estuary: Distribution, mobilization and migration. Sci Total Environ 2023; 905:167238. [PMID: 37741402 DOI: 10.1016/j.scitotenv.2023.167238] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Revised: 09/18/2023] [Accepted: 09/19/2023] [Indexed: 09/25/2023]
Abstract
Identifying the distribution features, mobilization mechanisms and migration processes of heavy metals (HMs) in estuarine sediments is essential to predict their potential toxicity risk and for following contamination remediation. In this study, high-resolution dialysis (HR-Peeper) and a sequential extraction procedure were employed to determine the porewater dissolved iron (Fe), manganese (Mn), arsenic (As), chromium (Cr), vanadium (V), selenium (Se), molybdenum (Mo), nickel (Ni), zinc (Zn) and their geochemical species fractions in sediments of the Xixi River Estuary, Xiamen, China. The results showed that at estuarine sites with high TOC and TS content, sulfate reduction is the main diagenetic pathway of OC degradation and directly inhibits the reduction of Fe/Mn oxides. The mobility of most HMs in porewater profiles was influenced by multiple factors, such as the adsorption-desorption by Fe/Mn oxides, HM-sulfide co-precipitation, and the degradation of OM under different redox conditions. However, no environmental correlation and control factors of Ni and Zn have been found. In addition, the profile-averaged distribution of most HMs showed a seaward increasing trend, probably due to the severe industrial wastewater discharge and increasing salinity responsible for the competitive adsorption of HM ions. The overall positive fluxes of all HMs, together with the higher positive diffusion fluxes of some HMs such as Mn, Cr, V and Zn, suggest that the HMs mobility in small estuarine sediments should be seriously reconsidered due to its high contamination potential.
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Affiliation(s)
- Yurui Li
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, PR China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Zheng Wang
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, PR China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Yu Cai
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, PR China; College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China
| | - Kai Xiao
- State Environmental Protection Key Laboratory of Integrated Surface Water-Groundwater Pollution Control, School of Environmental Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, PR China
| | - Zhanrong Guo
- College of Ocean and Earth Sciences, Xiamen University, Xiamen 361102, PR China.
| | - Feng Pan
- Fujian Key Laboratory of Coastal Pollution Prevention and Control, College of the Environment & Ecology, Xiamen University, Xiamen 361102, PR China; Key Laboratory of the Ministry of Education for Coastal and Wetland Ecosystems, Xiamen University, Xiamen 361102, PR China.
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Fan X, Xing X, Ding S. Enhancing the retention of phosphorus through bacterial oxidation of iron or sulfide in the eutrophic sediments of Lake Taihu. Sci Total Environ 2021; 791:148039. [PMID: 34118662 DOI: 10.1016/j.scitotenv.2021.148039] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [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: 03/25/2021] [Revised: 05/17/2021] [Accepted: 05/21/2021] [Indexed: 06/12/2023]
Abstract
Microbial activity can enhance the sequestration of phosphorus (P) in sediments, but little is known about the mechanisms behind it. In this study, sediment cores were sampled from the most eutrophic Meiliang Bay of Lake Taihu, and three treatments were set up in a laboratory incubation experiment, involving (a) the non-treated sediment cores, (b) inoculation, and (c) sterilization. The dissolved and labile iron (Fe) and P were obtained by high-resolution dialysis and the diffusive gradients in thin films (DGT) technique, respectively. AgI-based DGT was used for measuring the 2D distribution of labile sulfide. The bacterial community was investigated using a scanning electron microscope and 16S rRNA high throughput sequencing technique. The results showed that sterilization reduced the capacity of sediment to immobilize P, and that the critical sediment depth layer for microbial P sequestration was 0-10 mm. In addition, sterilization or inoculation significantly changes the structure of bacterial communities. Fe or S oxidation under micro-aerobic or anaerobic conditions played an important role in bacterial retention of P in the sediments. Nitrate-reducing coupling Fe(II)-oxidizing bacteria (Acidovorax) in the inoculated sediment and electrogenic sulfur-oxidizing bacteria (Candidatus Electronema) in the non-treated sediment were identified as the key bacterial genera responsible for the retention of P in sediments. This implies that bacterial communities could quickly establish the ability for negative feedback regulation by inoculation once the function and structure of indigenous sediment bacteria are seriously impaired, although this needs further validation in the field.
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Affiliation(s)
- Xianfang Fan
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xigang Xing
- General Institute of Water Resources and Hydropower Planning and Design, Ministry of Water Resources, Beijing, China
| | - Shiming Ding
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
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Wang Y, Yuan JH, Chen H, Zhao X, Wang D, Wang SQ, Ding SM. Small-scale interaction of iron and phosphorus in flooded soils with rice growth. Sci Total Environ 2019; 669:911-919. [PMID: 30970458 DOI: 10.1016/j.scitotenv.2019.03.054] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [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: 12/30/2018] [Revised: 03/04/2019] [Accepted: 03/04/2019] [Indexed: 06/09/2023]
Abstract
In the rhizosphere of flooded paddy soils, the solubilization, efflux, and uptake of phosphorus (P) are highly intertwined with iron (Fe) redox cycling. However, the direct observation of Fe-P coupling in the rhizosphere is challenging. This study combined high-resolution dialysis (HR-Peeper) and diffusive gradients in thin films (DGT) techniques to capture the one-dimensional distributions of soluble reactive P (SRP), soluble Fe(II), and labile P and Fe in the root zone of rice (Oryza sativa L.), respectively. The results show a depletion of soluble/labile P and Fe concentrations around the rice root zone, compared to anaerobic bulk soils that have two different soil Olsen-P levels. Two-dimensional (2D) measurements of DGT-labile P concentrations exhibited similar but stronger trends of P depletion due to uptake of P from soil solids. In low-P soil treatment, 97.8% soluble Fe(II) was depleted in the rice root zone relative to bulk soil, and a 540% enrichment of total Fe in Fe plaques appeared in comparison to that in high-P soil. This demonstrated that the rice plant showed an adaptive metabolic reaction to combat P deficiency in low-P soil by increasing Fe plaque formation. This reaction directly resulted in stronger depletion of P in low-P soil, as indicated by the results of 2D measurements of DGT-labile P concentrations. Moreover, the significant (P < 0.001, R2 = 0.175-0.951) positive corrections between SRP vs. soluble Fe(II), and DGT-labile P vs. Fe were observed in combination with pronounced peaks at the same position in the rice root zone, thus verifying that the cycling of Fe dictated P depletion. A notably lower value of the DGT-labile Fe/P ratio was found in high-P soil, which indicates a relatively higher risk of P release compared to that in low-P soil.
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Affiliation(s)
- Yu Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Jia-Hui Yuan
- State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Hao Chen
- State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Xu Zhao
- State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China
| | - Dengjun Wang
- National Research Council Resident Research Associate, United States Environmental Protection Agency, Ada, 74820, USA
| | - Shen-Qiang Wang
- State Key Laboratory of Soil and Sustainable Agriculture, Changshu National Agro-Ecosystem Observation and Research Station, Institute of Soil Science, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008, China.
| | - Shi-Ming Ding
- State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
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