GEOCHEMISTRY CHARACTERS OF THE CORE SEDIMENTS IN THE YANGTZE ESTUARY AND THE RESPONSE TO HUMAN ACTIVITIES

Element contents and grain sizes of core Y16 sediments in the Yangtze estuary were analyzed,and the age was also determined by activities of ¹³⁷Cs.The result indicates that,the vertical variation of element contents in the core sediments is closely related to the grain size component,and the core could be divided into three stages based on the variation of element contents:before 1966,1967 to 1989 and 1990 to 2006.R-model factor analysis indicates that,the terrigenous material input is the main factor controlling the variation of element contents in the core sediment.On the other hand,biological sedimentation and anthropogenic pollution may affect parts of elements.The element contents in the first two stages mainly connected with natural processes of the drainage basin,and the content of lead and zinc was partly affected by the anthropogenic pollution,which was diluted by the amount of sediment load from the Yangtze.In future,the environment of the Yangtze estuary will face more challenge,because of the sharply decreasing of the sediment load(sediment load of the Yangtze was only 85 million ton in 2006)and enhancing of the anthropogenic pollution due to the increasing consumption of coal and oil and the development of industry.