Transport Dynamics of Cr and Zn Between Deposited Sediment and Overlying Water.

Jinshan Lake, a typical river-connected lake located at middle-lower reaches of the Yangtze River, was selected as the study area. By field investigation and laboratory annular flume experiment, Cr and Zn migration mechanism between sediment and overlying water was quantitatively analyzed under different water depth and shear stress conditions. The results showed that (i) the content of Zn and Cr in the sediment dropped obviously at shear stress of >0.05 N m⁻¹. Zn was more likely to release from the sediment than Cr; (ii) For weak flow disturbance, a downward trend was observed for the dissolved Cr concentration due to the strong adsorption effects of fine particles with large specific surface areas on heavy metals. Dissolved Zn varied more greatly than Cr, because the conversion process between dissolved Zn and the particulate form was influenced to some extent by suspended sediment content; (iii) Under both weak and strong disturbance conditions the increasing rate of particulate Zn in overlying water was lower than Cr, which could demonstrate that Cr was more likely to be adsorbed to suspended sediment in the overlying water than Zn. [ABSTRACT FROM AUTHOR]