Abstract:In order to investigate in situ passivation process of compound contaminated soil contained Cd, As, Zn and Cu, simultaneous passivation test was implemented applying charcoal, iron powder and some corresponding compound on agricultural soil in Nandan county, Guangxi as objects. The results show that different simultaneous passivators lead to disparate consequence. Compound of calcium oxide and ferrous sulfate can passivate four metals simultaneously under proportion of 3% or 6% when they are mixed for 20 days. The best performance coming from compound of No.1 charcoal and iron powder conducted for 10 days with proportion of 6%, which decreases available Cd, As, Zn and Cu by 50.22%, 49.95%, 41.40% and 29.18%, respectively, and corresponding residual fraction increases by 6%, 13%, 14% and 1.8%, respectively, compared with blank group. Adding of every simultaneous passivator increases organic matter content in soil.