Abstract: 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.

Key words: Swan oxbow, ²¹⁰Pb, heavy metals, anthropogenic impact