Research of Effect of Groundwater Table Fluctuation on Migration Law of Cadmium

In this paper, we conduct the soil-column experiment on underground soil in a laboratory of Changping, Beijing, to simulate the effect of water table fluctuation on the cadmium migration law after twice pollution. The main job of the experience is to test the adsorption and desorption characteristics of the soil as well as the temporal and spatial distribution of cadmium ions in soil column. The experimental data show that (1) the two kinds of soil used in the test both have a strong adsorption capacity to cadmium ions, and the values could reach to 1026mg/kg and 2804mg/kg. (2) The dominant factor on cadmium ions migration under water table fluctuation is the soil adsorption when a small amount of cadmium ions are poured into soil column. On the other hand, convection plays a significant role in migration when plenty of cadmium ions are injected. (3) When plenty of cadmium nitrate are injected, the concentrations of cadmium ions in fluctuating zone increase with water table rise, and decrease with water table decline. The concentrations of cadmium ions, which exist in the saturated zone decrease when the water table rises and increase with water table decline.