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Distribution and Controlling Factors of Dissolved Gaseous Mercury and Reactive Mercury in Seawater Near yangtze river estuary

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中国海洋大学学报:英文版 2023年第5期22卷 1341-1352页

作者： YIN Pingping ZHENG Wen WANG Yan LIU Ruhai HE Xin SUN Haolin LI Dou School of Environmental Science and Engineering Ocean University of ChinaQingdao 266100China Key Laboratory of Marine Environment and Ecology Ministry of EducationSOSQingdao 266100China

Complex hydrocultural conditions in the estuary affect the migration and transformation of mercury.Using two voyages in July and October 2018,Dissolved Gaseous Mercury(DGM)and Reactive Mercury(RHg)were determined to explore the source,transformation and influence of DGM content in the adjacent waters of yangtze river estuary in summer and autumn.The results showed the contents of DGM and RHg in summer were higher than those in autumn,and both of them were higher than those in open sea.In summer and autumn,the yangtze river brought a higher concentration of DGM,and different flow direction and runoff resulted in differences in the high value region of the surface.The emergence of low-oxygen zones in summer was conducive to the production of DGM.In autumn,windy weather allowed seawater disturbances to promote the release of mercury from the underlying sediments,especially in shallow sea in northwest.RHg showed a higher concentration in the offshore than in the open sea in summer,but there was no such trend in autumn,reflecting the influence of less runoff input.DGM is the main product of RHg reduction,and there was a significant positive correlation between DGM and RHg in summer(r=0.356,Pyangtze river estuary was higher than that in the open sea.There was no significant difference of the release flux of mercury in summer and autumn.This article highlighted that the input of mercury from the yangtze river runoff promotes the release of mercury in seawater,and the hypoxic zone caused by eutrophication is conducive to the production of DGM.

关键词： yangtze river estuary dissolved gaseous mercury reactive mercury exchange flux hypoxic zone

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Sediment dynamics in the mudbank of the yangtze river estuary under regime shift of source and sink

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International Journal of Sediment Research 2022年第1期37卷 97-109页

作者： Dai Zhang Weiming Xie Jian Shen Leicheng Guo Yu Chen Qing He State Key Laboratory of Estuarine and Coastal Research East China Normal University Virginia Institute of Marine Science College of William & Mary

The southeastern portion of the yangtze river estuary (or yangtze estuary) was considered to be the deposition center and the mudbank of the yangtze river Delta.As the fluvial sediment supply began to decline in the 1980s and the reduction accelerated after the completion of the Three Gorge Dam in 2003,more fluvial sediment was trapped decreasing the suspended sediment concentration (SSC) environment in the river mouth area.Moreover,the accretion rate of the mudbank has slowed down in recent decades.In fact,the mudbank shrank and has faced a regime shift from sediment sink to source.A better understanding of the tidal-scale dynamics and spatial variability of the system is essential to explore the conversion of the sediment sources and sinks in the yangtze estuary affected by natural variations and human activities.Flow velocity,salinity,and suspended-sediment concentration during spring and neap tides were measured at three sites on the mudbank in July 1982 and July 2013.The variation in flow was not significant at all the sites measured in the study area from 1982 to 2013.However,the sediment dynamics changed remarkably over these three decades.The temporal distribution of the SSC increased in the bottom layer.The SSC was much larger during the early flood tide period in 2013.The tidal range increased by nearly 10%and the flood dominance increased in the study area from 1982 to 2013.The salinity dynamics underwent a transition from a stratified system in 1982 to a well-mixed system in2013.The landward sediment budget increased remarkably from 1982 to 2013.The decreased fluvial sediment supply,increased flood dominance,well-mixed salinity,and increased tidal range were directly responsible for the larger landward sediment budget and more severe erosion in the mudbank in 2013.The current results reveal the flow and sediment dynamics during the conversion of the sediment sink to source.Furthermore,it was determined that the sediment-starved process in the estuarine environment,which occurred due to the reduction i

关键词： Sink-source shift Fluvial sediment reduction Sediment flux yangtze river estuary

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Distribution of polycyclic aromatic hydrocarbons in sediments from Yellow river estuary and yangtze river estuary,China

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Journal of Environmental Sciences 2009年第12期21卷 1625-1631页

作者： HUI Yamei ZHENG Minghui LIU Zhengtao GAO Lirong State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China China Research Academy of Environmental Sciences Beijing 100012 China

Surface sediment samples collected from twenty-one sites of Yellow river estuary and yangtze river estuary were determined for sixteen priority polycyclic aromatic hydrocarbons （PAHs） by isotope dilution GC-MS method. The total PAH contents varied from 10.8 to 252 ng/g in Yellow river estuary sediment, and from 84.6 to 620 ng/g in yangtze river estuary sediment. The mean total PAH content of yangtze river estuary was approximately twofold higher than that of Yellow river estuary. The main reasons for the difference may be the rapid industrial development and high population along yangtze river and high silt content of Yellow river estuary. The evaluation of PAH sources suggested that PAHs in two estuaries sediments estuaries were derived primarily from combustion sources, but minor amounts of PAHs were derived from petroleum source in Yellow river estuary. PAHs may be primary introduced to Yellow river estuary via dry/wet deposition, wastewater effluents, and accidental oil spills, and yangtze river estuary is more prone to be affected by wastewater discharge.

关键词： PAHs sediment Yellow river estuary yangtze river estuary

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Dynamics of arsenic in salt marsh sediments from Dongtan wetland of the yangtze river estuary,China

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Journal of Environmental Sciences 2012年第12期24卷 2113-2121页

作者： Yongjie Wang Limin Zhou Xiangmin Zheng Peng Qian Yonghong Wu Department of Geography College of Resources and Environmental SciencesEast China Normal UniversityShanghai 200062China School of Geography Nantong UniversityNantong 226019China Department of Gography Minfiang UniversityFuzhou 350108China

The mobility and transformation of arsenic （As） in salt marsh sediments were investigated in Dongtan wetland of the yangtze river estuary, China. As in surface water, pore water and the rhizosphere sediments were quantified. The microcosm incubation experiments were conducted during the flooding of the sediments to examine As dynamics that occurred during changing redox conditions. The concentrations of dissolved As in pore water （0.04--0.95 ixmol/L） were significantly greater than that in surface water （0.03-0.06 lunol/L）. Under anoxic conditions, the reactive As could be initially mobilized by the reductive dissolution of Fe（III）（hydr）oxides. Subsequently, most of the dissolved As was likely to be associated with secondary iron （hydr）oxide phases and remained in solid phases. The seasonal variability of acid volatile sulfide concentrations suggest the anoxic conditions are enhanced during summer by Spartina alterniflora compared to Phragmites australis and Scirpus mariqueter, causing a notable increase in As mobility. Generally, there was a typical variation in redox conditions with season in salt marsh sediments of Dongtan wetland, in which the dynamics of As mobility and transformation possibly were controlled by iron, and all of this could be significantly influenced by the rapid spread of S. alterniflora.

关键词： Arsenic iron （hydr）oxides salt marsh sediment Spartina alterniflora yangtze river estuary

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Water quality model with multiform of N/P transport and transformation in the yangtze river estuary

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Journal of Hydrodynamics 2016年第3期28卷 423-430页

作者：王彪卢士强林卫青杨漪帆王道增 Shanghai Academy of Environmental Sciences Shanghai 200233 China Institute of Applied Mathematics and Mechanics and Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai University Shanghai 200072 China

As the yangtze river estuary and adjacent sea have been classified as a problem area with regard to eutrophication, it is important to explore the spatial and temporal variations of nitrogen and phosphorus （N/P） nutrients in this area. Based on danish hydraulic institute （DHI）＇s open platform Ecolab, a hydrodynamic and water quality model was developed for the yangtze river estuary, in which the transport and transformation processes of different forms of N/P nutrients were considered. Validations against measured data show that the model is overall reliable. Preliminary application of the model suggests that the model can simulate the characteristics of high phosphorus concentration area in the yangtze river estuary, and the high concentration area is closely related to the resuspension process of particulate phosphorus.

关键词： water quality model yangtze river estuary N/P transport and transformation

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The variations of suspended sediment concentration in yangtze river estuary

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Journal of Hydrodynamics 2015年第6期27卷 845-856页

作者：杨云平张明进李义天张为 Key Laboratory of Engineering Sediment Tianjin Research Institute for Water Transport Engineering Ministry of Transport State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan University

With the yangtze river estuary as an example, this paper analyzes the influence of human activity on the sea water content, the sediment content and the regional transport situation. In both flood seasons and dry seasons, as well as in the whole year, the sediment discharge rate and the suspended sediment concentration （SSC） in the estuary area of the yangtze river show decreasing trends. In the estuary area, the amount of sediment transported into the South and North Branches and the offshore area is also in a decreasing trend over the years. The SSCs at the sections at the entrances of the South Branch, the South Channel, the North Channel and the South Passage in the yangtze river estuary show decreasing trends during 1959-2011. The remote-sensing data reveal that for the same runoff and tidal current combination, the SSC in the surface water is decreased, caused by the dramatic decrease in the sediment discharge and the sediment content from the watershed. Although the SSC in the offshore area does not exhibit an apparent decreasing trend, the SSC in the nearshore area drops by 21.42% during the period of 2003-2011 as compared with that during the period of 1985-2002 before the impounding of the Three Gorges Reservoir. The sediment re-suspension in the estuary slows down the reduction of the SSC. The period of2003-2011 is dry years for the yangtze river, when the flow is relatively low. The peak value of the SSC in the coast area shifts inwards for about 1/60 of longitude. Due to the deepwater channel improve- ment project in the North Passage at the yangtze river estuary in 1998, the SSC in the waterway area is decreased. With the de- crease of the divided flow ratio and the sediment splitting ratio in the entrance and the exit of the North Passage, the SSC in the upper and lower reaches of the North Passage during the period of 2008-2011 is decreased by about 14.25% as compared with that during the period of 2000-2007. Primarily due to the jetty at the south side, the SSC in the middle reach shows an increa

关键词： suspended sediment concentration trend and cause yangtze river estuary

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Analysis on the Circulation of the yangtze river estuary Based on ADCP Measurements

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China Ocean Engineering 2007年第3期21卷 485-494页

作者：严以新陶爱峰于东生杨金艳 State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai University Third Institute of Oceanography of State Oceanic Administration

According to analysis on field data obtained by ADCP （Acoustic Doppler Current Profiler）, the flow regime of the yangtze river estuary is studied by use of a 3-D numerical model. The flow field characteristics, under the influence of Coriolis force, saltwater intrusion and freshwater inflow and tidal current interaction, are depicted in details. The main driving forces and some important effective factors of lateral, longitudinal and horizontal circulation are also analyzed.

关键词： yangtze river estuary estuarine circulation Acoustic Doppler Current Profiler （ADCP）

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THE INFLUENCE OF THE THREE GORGES PROJECT ON THE MOUTH BAR OF THE yangtze river estuary——MATHEMATICAL SIMULATION AND PREDICTION OF EROSION AND SILTATION

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Journal of Geographical Sciences 1991年第4期2卷 54-69页

作者： Zhu Huifang Zhou Jixiang Institute of Estuarine&Coastal Research East China Normal University

The process of deposition at the mouth bar of the yangtze river estuary is a very complex process.In this paper,the elevation variance of the mouth bar is considered as a stochastic process that is affected by many factors.A mathematical model of multiple regression is developed.This model is correct and reliable based on the synthetical analysis of significance of the regression equation,multiple correlation coefficient and standard deviation.The fitted computation is performed using the mathematical model and the result.It shows that the fitted value conforms to the observed data.Thus,the mathematical model can predict the changing tendency at the mouth bar,which is caused by various changes of flow and sediment discharge for construction of the Three Gorges Project.

关键词： mathematical model mouth bar yangtze river estuary

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Temporal and spatial changes of suspended sediment concentration and resuspension in the yangtze river estuary

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Journal of Geographical Sciences 2003年第4期13卷 498-506页

作者： CHEN Shenliang, ZHANG Guoan, YANG Shilun(State Key Laboratory of Estuarine and Coastal Research, East China Normal University,Shanghai 200062, China) East China Normal University State Key Laboratory of Estuarine and Coastal Research 上海 200062

A detailed analysis of suspended sediment concentration (SSC) variations over a year period is presented using the data from 8 stations in the yangtze river estuary and its adjacent waters, together with a discussion of the hydrodynamic regimes of the estuary. Spatially, the SSC from Xuliujing downwards to Hangzhou Bay increases almost constantly, and the suspended sediment in the inner estuary shows higher concentration in summer than in winter, while in the outer estuary it shows higher concentration in winter than in summer, and the magnitude is greater in the outer estuary than in the inner estuary, greater in the Hangzhou Bay than in the yangtze river estuary. The sediments discharged by the yangtze river into the sea are resuspended by marine dynamics included tidal currents and wind waves. Temporally, the SSC shows a pronounced neap-spring tidal cycle and seasonal variations. Furthermore, through the analysis of dynamic mechanism, it is concluded that wave and tidal current are two predominant factors of sediment resuspension and control the distribution and changes of SSC, in which tidal currents control neap-spring tidal cycles, and wind waves control seasonal variations. The ratio between river discharge and marine dynamics controls spatial distribution of SSC.

关键词： suspended sediment concentration temporal and spatial changes sediment resuspension yangtze river estuary

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SEDIMENT TRANSPORT IN THE yangtze river estuary

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International Journal of Sediment Research 2001年第2期16卷 189-193页

作者： SHEN Zhigang1 1 Department of Engineering Mechanics, Shanghai Jiao Tong University, 1954 Hua Shan Road, Shanghai 200240, China. Department of Engineering Mechanics Shanghai Jiao Tong University 1954 Hua Shan Road Shanghai 200240China.

The hydrodynantic and the sediment transport patterns within the estuary of the yangtze river are complex because of interaction of fluvial and the tidal forces, depending on freshwater discharge and tidal range. Based on the data measured in recent years, this paper discusses the characteristics of flow and sediment movement in the yangtze river estuary and their influences on the evolution of the estuary.

关键词： yangtze river estuary Sediment transport Tidal current river evolution Stream flow

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