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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

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

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 s

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

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)

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 *** 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 ***,the accretion rate of the mudbank has slowed down in recent *** 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 *** velocity,salinity,and suspended-sediment concentration during spring and neap tides were measured at three sites on the mudbank in July 1982 and July *** variation in flow was not significant at all the sites measured in the study area from 1982 to ***,the sediment dynamics changed remarkably over these three *** temporal distribution of the SSC increased in the bottom *** SSC was much larger during the early flood tide period in *** tidal range increased by nearly 10%and the flood dominance increased in the study area from 1982 to *** salinity dynamics underwent a transition from a stratified system in 1982 to a well-mixed system *** landward sediment budget increased remarkably from 1982 to *** 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 *** current results reveal the flow and sediment dynamics during the conversion of the sediment sink to ***,it was determined that the sediment-starved process in the estuarine e

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

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

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Journal of Ocean University of China 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 *** 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 *** 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 *** 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 *** emergence of low-oxygen zones in summer was conducive to the production of *** autumn,windy weather allowed seawater disturbances to promote the release of mercury from the underlying sediments,especially in shallow sea in *** 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 *** 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 *** was no significant difference of the release flux of mercury in summer and *** 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

Recognition on the forming-vanishing process and underlying mechanisms of the hypoxia off the yangtze river estuary

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Science China Earth Sciences 2015年第2期58卷 628-648页

作者： WEI QinSheng WANG BaoDong CHEN JianFang XIA ChangShui QU DaPeng XIE LinPing First Institute of Oceanography State Oceanic Administration Key Laboratory of Marine Chemistry Theory and Technology Ministry of Education Ocean University of China Second Institute of Oceanography State Oceanic Administration

On the basis of compiled multidisciplinary historical data in 2006-2007 and incorporation of relevant simulation results and re- mote sensing data, we performed an in-depth study of the generation and dissipation process of the hypoxic zone and its distribu- tion morphology and structure off the yangtze river estuary, Based on the hydrological circulation dynamics, reproduction of phytoplankton （leading to the decomposition of organic matter）, and other factors, we comprehensively and systematically inves- tigated the generation and dissipation of the hypoxic zone and underlying mechanisms for the seasonal variation in its position, explored the multi-factorial synergistic reactions during the generation and dissipation process of the hypoxic zone, and revealed the controlled mechanism for the morphology and structure of the hypoxic zone＇s distribution. Our studies indicate that in the winter and spring seasons, the hydrological environment off the yangtze river estuary provides a water body with relatively low contents of dissolved oxygen （DO）, which is the background for the formation of a hypoxic zone. After entering into the summer season, the hypoxic zone gradually develops towards the north and becomes mature. Because of the impact of the terrain, local decomposition of organic matter, and upwelling of the Kuroshio subsurface water in July-August, the bypoxic zone off the Yang- tze river estuary exhibits the characteristics of discontinuous distribution in space and has a south and north ＂dual-core＂ structure in the inner continental shelf. In addition, there is a hypoxic core in the eastern outer continental shelf. The degrees of hypoxia vary for different areas; they are strongest overall in the north, next strongest in the south; they are weakest on the outer continen- tal shelf. In summer, the hypoxic zone in the north is related to the northward differentiation of the southern hypoxic zone and re- sults from local development and intensification. In Augus

关键词： yangtze river estuary hypoxic zone stratification flow field environment organic decomposition

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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 *** 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 *** model is correct and reliable based on the synthetical analysis of significance of the regression equation,multiple correlation coefficient and standard *** fitted computation is performed using the mathematical model and the *** shows that the fitted value conforms to the observed ***,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

Phytoplankton Assemblage of yangtze river estuary and the Adjacent East China Sea in Summer, 2004

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Journal of Ocean University of China 2006年第2期5卷 123-131页

作者： LUAN Qingshan SUN Jun SHEN Zhilian SONG Shuqun WANG Min College of Marine Life Science Ocean University of China Qingdao 266003 P. R. China Key Laboratory of Marine Ecology ＆ Environmental Science Institute of Oceanology Chinese Academy of Sciences Qingdao 266071 P.R. China

A cruise was conducted from late August to early September 2004 with the intention of obtaining an interdisciplinary understanding of the yangtze river estuary including the biological, chemical and physical subjects. Water sample analysis indicated that total phytoplankton species richness was 137. Of them 81 were found in Bacillariophyta and 48 in Pyrrophyta, accounting for 59.1% and 35.0% respectively. The average cell abundance of surface water samples was 8.8 ×104 cells L^-1, with the maximum, 102.9×104 cells L^-1, encountered in the area （31.75°N, 122.33°E） and the minimum, 0.2×10^4 cells L^-1, in （30.75°N, 122.17°E）. The dominant species at most stations were Skeletonema costatum and Proboscia alata f. gracillima with the dominance of 0.35 and 0.27. Vertical distribution analysis indicated that obvious stratification of cell abundance and dominant species was found in the representative stations of 5, 18 and 33. Shannon-Wiener index and evenness of phytoplankton assemblage presented negative correlation with the cell abundance, with the optimum appearing in （30.75°N, 122.67°E）. According to the PCA analysis of the environmental variables, elevated nutrients of nitrate, silicate and phosphate through river discharge were mainly responsible for the phytoplankton bloom in this area.

关键词： yangtze river estuary phytoplankton nutrients eutrophication Skeletonema costatum Proboscia alata f.gracillima