Differences of soil cadmium in mining subsidence area between Guqiao and Xinzhuangzi in Huainan

Soils in Huainan Guqiao and Xinzhuangzi coal mining-induced subsidence area were sampled and tested to study the distribution of surface cadmium in the subsidence area and the influence of subsidence time and vermiculite filling on the cadmium distribution in the soil. The results of the study showed that the total cadmium content in the surface soil of the Xinzhuangzi mine was 9.37 times higher than that of Guqiao mine due to the long-term cumulation and underlying filling gangue. The soil cadmium content in Guqiao mining area showed a downward trend and then increased from the surface of the soil. Affected by leaching and topography, the soil cadmium in the filling and reclaiming area of Xinzhuangzi has two change trends with depth. First, in high terrain the cadmium content decreases firstly and then increases, while in low terrain the cadmium content increases firstly and then decreases.