The five chemical associations of heavy metals have been extracted continuously using the Tessier extracting method. Results show that Cu, Pb, Fe, Zn and Cr in the sediments are mainly distributed in residual fraction...The five chemical associations of heavy metals have been extracted continuously using the Tessier extracting method. Results show that Cu, Pb, Fe, Zn and Cr in the sediments are mainly distributed in residual fraction, while the major chemical association of Mn is carbonates. Carbonate heavy metals are converted into Fe-Mn oxides in autumn. And in the low tidal flat, after carbonates have changed into ionic heavy metals, some of the elements are transported to the overlying water. Cu, Pb, Fe and Mn have good correlations with each other, and Zn, Cr also show their similarity of chemical behavior in the sediments.展开更多
To select the location of sewage outlet in the sewage disposal program of Shanghai is a rather comprehensive problem which covers many fields and has great influences. The sewage outlet at Zuyuan, about 10 km away fro...To select the location of sewage outlet in the sewage disposal program of Shanghai is a rather comprehensive problem which covers many fields and has great influences. The sewage outlet at Zuyuan, about 10 km away from Wusongkou, is situated on the south bank of the South Channel in the Yangtze Estuary. In order to determine the water depth which can guaranteed the safe draining of sewage at the outlet, a statistical method is adopted in this paper for the determination of the guarantee rate of safe draining at Zuyuan sewage outlet by means of the characteristics of fluvial process and previous topographic data, and the guaranteed water depth for safe draining is then determined.展开更多
基金This work is supported by the National Natural Science Focal Projects Foundation of China(Grant No.40131020)the National Natural Science Foundation of China(Grant No.49833030)+2 种基金the Venus Program Foundation for Young Scientists of Shanghai(Grant No.97QA14023)its Tracking Program(Grant No.01QMH1406)the Dawn Program of Shanghai Ecucational Development Foundation.
文摘The five chemical associations of heavy metals have been extracted continuously using the Tessier extracting method. Results show that Cu, Pb, Fe, Zn and Cr in the sediments are mainly distributed in residual fraction, while the major chemical association of Mn is carbonates. Carbonate heavy metals are converted into Fe-Mn oxides in autumn. And in the low tidal flat, after carbonates have changed into ionic heavy metals, some of the elements are transported to the overlying water. Cu, Pb, Fe and Mn have good correlations with each other, and Zn, Cr also show their similarity of chemical behavior in the sediments.
文摘To select the location of sewage outlet in the sewage disposal program of Shanghai is a rather comprehensive problem which covers many fields and has great influences. The sewage outlet at Zuyuan, about 10 km away from Wusongkou, is situated on the south bank of the South Channel in the Yangtze Estuary. In order to determine the water depth which can guaranteed the safe draining of sewage at the outlet, a statistical method is adopted in this paper for the determination of the guarantee rate of safe draining at Zuyuan sewage outlet by means of the characteristics of fluvial process and previous topographic data, and the guaranteed water depth for safe draining is then determined.
