Remediation Experiments of Attapulgite Clay to Heavy Metal Contaminated Soil

In order to reduce the heavy metals in vegetables, the excellent physical and chemical abilities of attapulgite clay were applied to potting remediation experiments on heavy metal contaminated topsoil sampled from Tongling city, Anhui province. The proportions of attapulgite clay to contaminated topsoil were 1:10, 1:20, 1:40, 1:100 plus one sample containing only contaminated topsoil. The small Chinese cabbage and Beijing fast cabbage were chosen as the test plants. The potting remediation experimental results indicate that the pH of the potting soil improved from 5 to 8, therefore improving the condition of the soil and increasing the adsorbability of attapulgite clay for heavy metals. Adding different amounts of attapulgite clay to these two kinds of vegetables, the average repair rates of Cu, Zn and Cd were 31.50%, 26.15% and 34.92%, respectively. The best proportion of the attapulgite and topsoil is 1:20 which provides optimum results for improvement to contaminated topsoil.