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General Session 2: Marine & estuarine biogeochemistry |
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Radium in the lower reaches of the Yellow River: Concentrations and fluxes under the influence of the Water-Sediment Regulation Scheme
GS2-06-S
Disong Yang* , Key Laboratory of Marine Chemistry Theory and Technology (MCTL), Ministry of education, Ocean University of China, Qingdao 266100, PR China
Bochao Xu, Key Laboratory of Marine Chemistry Theory and Technology (MCTL), Ministry of education, Ocean University of China, Qingdao 266100, PR China
Xueyan Jiang, Key Laboratory of Marine Chemistry Theory and Technology (MCTL), Ministry of education, Ocean University of China, Qingdao 266100, PR China
Presenter Email: ouc_yangdisong@163.com
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| Radium isotopes are excellent geochemical tracers for studying oceanographic processes, such as quantifying submarine groundwater discharge (SGD), tracing water migration. Yellow River, one of the longest and most turbid river all over the world, is expected to make a great contribution to Radium budget of the global ocean. Impacted by serious soil erosion in the upper and middle reaches of the Yellow River, the situations of sedimentation and no water flow in the lower reaches became more serious. In order to solve this problem, Water-Sediment Regulation Scheme (WSRS) has been played an important role in changing the transports of water and sediment, and avoiding sedimentation in reservoirs and the lower reaches of the Yellow River. In this study, we investigated the concentrations of three kinds of radium isotopes (223Ra, 224Ra and 226Ra) in the lower reaches of the Yellow River on monthly scale from 2014 to 2015, which were 0.48 dpm/100L to 2.87 dpm/100L, 28.28 dpm/100L to 150.95 dpm/100L, and 14.14 dpm/100L to 71.11 dpm/100L, respectively. WARS enhanced the radium activity. Suspended particulate matter (SPM) is the dominant factor for radium concentrations. Significant higher radium concentrations, especially the short-lived 223Ra and 224Ra (3-5 times higher), were observed during the month of WSRS. For short-lived 223Ra and 224Ra, the pore water and desorption is the main source, and for long-lived 226Ra, the water from the Xiaolangdi Reservoir is another important radium source. In 2014, combined with the results of laboratory simulation experiment of radium desorption from particulate matters, we estimate that the annual fluxes of 224Ra and 226Ra were 12.10×1012 dpm y-1, 5.95×1012 dpm y-1, respectively. Yellow River is the highest radium concentrations and fluxes ranking the global major rivers. |
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