A Cd anomaly was found around the Dongting Lake in Hunan Province by previous soil geochemical survey. In order to investigate the formation, ways of transportation and fluxes of As and heavy metals such as Cd, sampling points were designated at the key locations in the Dongting Lake water system. Samples of raw water, water filtrated by 0.45 μm filters and 0.20 μm ones, and filtrated suspended sediments were collected at each sampling location. As and heavy metals such as Cd, Pb etc. in the water and sediment samples were analyzed. As was found concentrated at Zishui, Xiangjiang and its upstream branches like Xihe and Leishui; Pb,Zn were concentrated at Xiangjiang, Xihe and Leishui; and Cd concentrated at Xiangjiang, Leishui and Miluojiang. Dissolved forms were found to be the dominant of the total contents for As, Ni, Cd and Zn. The proportion of dissolved to the total was controlled by pH and temperature of the water. As,Zn,Cu,Cd,Pb and Cu contents in the suspended sediments from Xiangjiang, Xihe, Leishui and Miluojiang were higher than in the other water systems due to the mining activities for metals at the drainage basins. As was transported more in the form of the dissolved form than in the particulate one, but Pb,Zn,Cu,Cd and Ni were more transported in the form of the particulate. Xiangjiang is the biggest source of As,Zn,Cu and Cd for the Dongting Lake with the annual fluxes of 961.43 t, 478.90 t, 101.67 t and 59.58 t respectively.
