长江中游天鹅洲沉积物重金属元素记录对流域人类活动的响应

利用2007年4月采集于天鹅洲长江故道柱状沉积物中过剩210Pb深度—活度的分布规律及柱样的沉积学特征结合沉积事件记录进行定年，并通过ICP-AES、ICP-MS测定了沉积物中元素含量，包括K、Ca、Na、Mg、Al、Fe、Mn、Ti、Cr、Cd、V、Zn、Pb、Cu、Ni、Co、Cs、U、Ga、Ba、Sr，重建了50年以来长江中游元素地球化学记录的演变过程.通过重金属元素含量以及重金属标准化比值表明，天鹅洲长江故道沉积物剖面与长江河道变迁及流域人类活动具有很好的相关性:1950～1990年，处于工业化前期，沉积物重金属元素含量变化幅度较小，主要受物源和沉积环境等自然因素控制；1990～2007年，流域工业化进程加快，人类活动带来的污染增多，同时流域水利工程的兴修，使得来沙量降低，河流自净能力减弱，沉积物重金属含量显著提高.环境问题日益显著，亟需环境学者密切关注.

Response to the anthropogenic impact on heavy metals in the sediment core from the Swan oxbow in the middle Yangtze River

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 elements (K, Ca, Na, Mg, Al, Fe, Mn, Ti, Cr, Cd, V, Zn, Pb, Cu, Ni, Co, Cs, U, Ga, Ba, Sr) in the sediment core detected by ICP-AES and ICP-MS. The results demonstrated that the regional environment is subjected to the human activities and the channel migration of the 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.