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Zhong Q, Wang H, Wang Q, Chen S, Lin J, Huang D, Yu T. Study of Ra desorption processes in an estuary system with high-turbidity at the Southeast China. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2023; 259-260:107108. [PMID: 36638725 DOI: 10.1016/j.jenvrad.2023.107108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 01/02/2023] [Accepted: 01/05/2023] [Indexed: 06/17/2023]
Abstract
Radium (Ra) isotopes are extensively used as geochemical tracers for studying water mass mixing and submarine groundwater discharge in marginal and coastal seas. However, river-borne particles and seafloor sediments are an important source of Ra in marine systems due to Ra desorption. Therefore, it is necessary to study the desorption behaviors of Ra isotopes in river sediment or suspended particles. Here, the desorption behaviors of four Ra isotopes (223Ra, 224Ra, 226Ra, and 228Ra) in the Zhangjiang River sediments were investigated by a series of designed variable-controlling experiments in the laboratory. Within the designed salinity range, desorption amounts of Ra isotopes increased with increasing salinity, and when the salinity was greater than 15 ppt, Ra desorption reached an equilibrium state. Overall, desorption of Ra isotopes increased with the decrease of particle grain size, however, the desorption fractions of 224Ra and 228Ra decreased with decreasing particle size due to the increase of original Ra activities in smaller sediment particles. In the experiments, we found that two sediment samples with similar mean grain size (3.8 μm and 3.3 μm) and similar grain size distributions had significantly different Ra desorption under the same conditions. The results of mineral composition analysis based on X-ray diffraction showed that these two samples had different percentages of kaolinite, quartz, and plagioclase, which indicated that the mineral composition of particles had an important effect on Ra isotope desorption. In conclusion, salinity, particle grain size, and mineral composition all had significant effects on Ra desorption behaviors of sediment particles. Based on the above desorption experiments, the desorbed fluxes of four Ra isotopes from river-borne sediments to the Dongshan Bay were estimated to be (5.95 ± 1.47) × 107 Bq yr-1 for 223Ra, (1.95 ± 0.27) × 109 Bq yr-1 for 224Ra, (2.73 ± 0.47) × 108 Bq yr-1 for 226Ra, and (1.26 ± 0.20) × 109 Bq yr-1 for 228Ra, respectively.
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Affiliation(s)
- Qiangqiang Zhong
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China
| | - Hao Wang
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China; College of Marine Sciences, Shanghai Ocean University, Shanghai, 201306, China
| | - Qiugui Wang
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Suiyuan Chen
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China; College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361005, China
| | - Jing Lin
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China
| | - Dekun Huang
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China; Observation and Research Station of Island and Coastal Ecosystem in the Western Taiwan Strait, Ministry of Natural Resources, Xiamen, 361005, China; Fujian Provincial Station for Field Observation and Research of Island and Costal Zone in Zhangzhou, Zhangzhou, 363216, China; Key Laboratory of Global Change and Marine-Atmospheric Chemistry, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361000, China.
| | - Tao Yu
- Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China
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Su W, Ma Y, Wang Q, Yan Q, Lu X, Ma Z, Yi L, Liu X, Chen F, Han F, Xu Z. Effects of salinity and particle size on radium desorption from river sediments in the Qinghai-Tibet Plateau. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2022; 241:106771. [PMID: 34775288 DOI: 10.1016/j.jenvrad.2021.106771] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2021] [Revised: 10/21/2021] [Accepted: 11/04/2021] [Indexed: 06/13/2023]
Abstract
Natural radium isotopes have been widely used to study groundwater discharge in different systems. Therefore, it is of great significance to understand the desorption behavior of radium isotopes on sediments to trace water-land exchange processes. However, there is very limited studies observing the desorption Ra isotopes to lake water of the brine lake. 224Ra desorption experiments with different salinities and particle sizes were carried out by collecting samples of brackish water from Qinghai Lake, brine from Dabuxun Lake and river sediments entering the lakes. The results show that the desorption activity of 224Ra from the river sediments to lake water of Qinghai Lake is 0.2 dpm/g when the salinity is 10.07‰. The maximum desorption activity of 224Ra from river sediments to lake water of Dabuxun Lake is 0.195 dpm/g at a salinity of 40.81‰. A salinity of 41.81‰ and particle size of 16.28 μm are the threshold points affecting the desorption behavior of Ra. When the salinity is less than 40.81‰, the desorption activity of Ra increases linearly with increasing salinity. When the salinity is greater than 40.81‰, the desorption activity of Ra decreases nonlinearly with increasing salinity and tends toward a stable low value. When the particle size is larger than 16.28 μm, the small particle size promotes desorption. The smaller the particle size is, the greater the desorption activity is. When the particle size is less than 16.28 μm, the small particle size inhibits desorption. The smaller the particle size is, the smaller the desorption activity. The co-precipitation of Ra2+ with supersaturated Ca2+, SO42- and other ions may be the main reason for the threshold point of salinity and particle size in Ra desorption process in salt lake system.
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Affiliation(s)
- Weigang Su
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China; Qinghai Earthquake Agency, Xining, 810001, China
| | - Yujun Ma
- Key Laboratory of Tibetan Plateau Land Surface Processes and Ecological Conservation, Ministry of Education, Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining, 810008, China
| | - Qiugui Wang
- Key Laboratory for Water Quality and Conservation of the Pearl River Delta, Ministry of Education, School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China
| | - Qiongxiong Yan
- Qinghai Salt Lake Industry Co., Ltd, Golmud, 816000, China
| | - Xiaohang Lu
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Zhe Ma
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Lei Yi
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Xiaobao Liu
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fuhong Chen
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Fengqing Han
- Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Chinese Academy of Sciences and Qinghai Provincial Key Laboratory of Geology and Environment of Salt Lakes, Qinghai Institute of Salt Lakes, Chinese Academy of Sciences, Xining, 810016, China; University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Zhengfan Xu
- Guangdong Key Laboratory of Radioactive and Rare Resource Utilization, Guangzhou. 510006, China
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Li L, Zhong Q, Du J. Radium desorption behavior of riverine suspended sediment: Theoretical and experimental. JOURNAL OF ENVIRONMENTAL RADIOACTIVITY 2021; 234:106644. [PMID: 33991743 DOI: 10.1016/j.jenvrad.2021.106644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 03/15/2021] [Accepted: 05/01/2021] [Indexed: 06/12/2023]
Abstract
Radium desorption from riverine or suspended sediment is an important source term of Ra isotopes in estuarine water, which is one of the significant factors affecting the source/sink material balance for Ra applications, such as estimating submarine groundwater discharge flux in coastal zones. In this paper, a theoretical model is proposed to study Ra desorption considering several influencing factors, including salinity, particle size and size distribution, alpha recoil range of atoms in the sediment grains, and grain surface roughness. The results of the model parameter sensitivity analysis show that the alpha-decay recoil can improve the number of total exchangeable Ra on grain surfaces, but it is more significant for sediment of small grain size. Sediment with large mean grain size may contain a considerable number of smaller particles, which may facilitate the Ra desorption quantity. Due to the relatively low concentrations of Ra in natural mineral, the Ra desorption quantity is not sensitive to the roughness of the sediment grain surfaces. The model fits well with the indoor experimental data, by fitting the experimental data or quoting the literature values, the desorption parameters (A, B, α, β) in the model can be determined to estimate the total number of exchangeable Ra of a sediment and also predict the Ra desorption of sediments in different conditions.
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Affiliation(s)
- Linwei Li
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200241, China
| | - Qiangqiang Zhong
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200241, China; Laboratory of Marine Isotopic Technology and Environmental Risk Assessment, Third Institute of Oceanography, Ministry of Natural Resource, Xiamen, 361005, China
| | - Jinzhou Du
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, 200241, China.
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