Preliminary Study On The Transport Of Heavy Metals From River Basin To The Coastal Shelf Of East China Sea

In the present thesis, the metals and rare earth elements in the suspended particles and the sediment core were determined using ICP-MS and ICP-AES. The suspended particles were collected in the Yangtze River, major rivers of Zhejiang, Yangtze River Estuary and the Zhe-M coast and the sediment core from the Swan oxbow of the middle Yangtze River was collected in April 2007. The aim of the thesis was to study the distribution of metals and evaluate the influence of the waste using the metal fluxes. The result is helpful for the research of the ecological conservation.The characteristics heavy metals and the rare elements in the suspended particulates of the middle and lower reaches of the Yangtze River basin, major tributaries and the Poyang Lake, Dongting Lake were analyzed. The heavy metals along the mainstream show that the lake is greater than tributaries and tributaries are greater than the distribution of the main stream. In recent years, heavy metal content will increase with the reduced sediment load and human activities, while the rare earth elements show obvious terrestrial features.The concentration of heavy metals of Xuliujing fixed station on December 2008 show obvious features. The concentration of heavy metals of the suspended particles increases with the decline of the sediments of the Yangzte River. After estimation, the flux calculations at Xuliujing indicate that the Yangtze River transports 151.68t/a of Cd,9248.07t/a of Pb,15282.80 t/a of Cr,8097.07 t/a of Ni,10659.57 t/a of Cu, 29715.46t/a of Zn to the East China Sea.The concentration of the suspended particles in rivers of Zhejiang Province was studied.There are some differences in fluxes of metals in every river because of the concentration of TSM and water discharge,4.74t/a of Cd,416.41t/a of Pb,1575.68 t /a of Cr,607.45 t/a of Ni,753.97 t/a of Cu,2028.64 t/a of Zn to the East China Sea. The results of the rare elements show that the weathering and translation in Zhejiang Rivers have the obvious terrestrial characteristics and the extent is little than Yangtze River.By studying the Yangtze River estuary and a large area of Zhe-M coastal stations of the heavy metal content, varied greatly by the influence of different water masses. The highest values appear in the vicinity of the north section of the Yangtze Estuary and Zhoushan sea outside the station; The data of REEs show that the sediment source area of Zhe-M coast can be divided:by the area influced that land-based sources and effects of the Yangtze River freshwater flow and the other area effectd that coastal sea areas and coastal areas of Taiwan warm current interaction.The chronological dating of the sediment core from the Swan oxbow of the middle Yangtze River in April 2007 was determined by the combination of excess 210Pb (210Pbex) profile and the sedimentary characteristics. Environmental changes in the upper and middle reach of the Yangtze River in China in the last 50 years have been recorded by the concentration of heavy metals in the sediment core. The results demonstrated that the regional environment is subjected to the human activities and the channel migration of Yangtze River. During 1950s-1990s, low concentration and scale of the metal/aluminum variation suggested that the elements was mainly controlled by the weathering of river basin and the sedimentary environment. Since 1990s, substantially increasing of heavy metals suggested heavier pollutant of the river basin resulting from both increasing of industrialization and hydraulic engineering construction of the river basin. The decreasing of sediment load of the Yangtze River from hydraulic construction practices in recent years potentially diminished self-purification of river, thus negatively impact on environment of river basin.