Abstract:

 The Taihu Lake located at the lower reaches of Yangtze River is a shallow large lake The Cd and Pb pollution history of sediments of the Taihu Lake and the soils of its intake areas has been reconstructed based on 137Cs and 210Pb depositional dating at 4 sections representing different depositional environments The results show that the Cd and Pb concentrations in the lake sediments were roughly equal to that of background level in the intake areas before 1980; while since then the concentrations have become considerably higher, which is just basically corresponding to the industrialization progress there It is thus inferred that the industrialization has been the main reason for the increase in Cd and Pb concentrations in the lake sediments The accumulated amounts of Cd and Pb in the lake sediments have been 146 t and 25980 t respectively since 1900, among them 40 t and 6777 t were due to the intake from Tiaoxi river, 36 t and 6023 t from Yili river, and 71 t and 13179 t from other rivers (say Tiao river, Ge river and the Grand Canal), respectively It is seen that the above mentioned other rivers have been the main sources for the accumulated Cd and Pb in the Taihu Lake The peak period of the accumulation was 8090s of the last century The outputs of Cd and Pb from the Grand Canal have been 2826 t and 3419 t since 1980, respectively; while the total outputs of Cd and Pb from the basin of Tiao river have been 1370 t and 1585 t, among them 890 t of Cd and 610 t of Pb have been due to human activities, corresponding to 6496 ％ and 3847 ％ of the total outputs of Cd and Pb respectively The total outputs of Cd and Pb from the basin of Yili river have been 1009 t and 1063 t since 1980, respectively, among them 696 t of Cd and 500 t of Pb have been due to human activities, corresponding to 6868 ％ and 4708 ％ of the total outputs of Cd and Pb respectively It shows that the accumulation of Cd due to human activity has been over that of natural denudation in the Taihu Lake drainage area The key measures for improving the environmental quality of the lake sediments should be to decrease the total discharge of Cd and Pb from industrialization progress and to control the outputs of Cd and Pb from the Grand Canal

Key words:

Key words: heavy metal pollution; reconstruction of history; regional soil; Taihu lake