长江口外海域岩心沉积物地球化学特征及其对人类活动的响应

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

对长江口外海域Y16站岩心沉积物中元素含量和粒度组成进行了分析,并通过137Cs测定了年龄。结果表明,该岩心沉积物中元素含量在垂向上的变化与沉积物粒度组成的变化密切相关,根据元素含量的变化特征可将其分为3段:1966年之前、1967—1989年和1990—2006年。R型因子分析表明,影响该岩心沉积物中元素含量变化的主要因素为陆源物质供给。另外,生物沉积作用和人为污染对部分元素含量的变化有一定影响。元素含量的变化特征在前两个阶段主要与流域自然过程相联系,在后一阶段(1990—2006年)人为污染对沉积物中Pb和Zn元素含量的变化有所影响,但这种影响在长江大量输沙的背景下被明显减少。目前,由于长江输沙量的大幅下降(2006年长江输沙量仅为0.85亿t)以及人为污染影响程度的增强(煤、石油燃料消耗的持续增加以及工业的持续发展),未来长江口海域重金属元素的污染情况将面临更大的挑战。

Element contents and grain sizes of core Y16 sediments in the Yangtze estuary were analyzed, and the age was also determined by activities of 137 Cs. 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. Rmodel 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 an- thropogenic 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.