Passivation remediation method for arsenic-cadmium combined contaminated soil of agricultural land

The invention discloses a passivation remediation method for arsenic-cadmium combined contaminated soil of agricultural land, and belongs to the technical field of soil remediation. The method comprises the following steps: S1, determining the optimal dissolution pH range of As and Cd in the soil through a contaminated soil As and Cd dissolution curve experiment; S2, determining the addition amount of an acid-base regulator required for regulating the pH of the soil; S3, determining the addition amount of zero-valent iron in a soil sample according to the pollution degree of As; and S4, passivating the soil. The scheme determined in the steps S1-S4 is taken as a farmland small-scale experiment, and after the pollution characteristics of the polluted soil are known, a remediation scheme of an actual field experiment is determined according to the small-scale experiment. According to the method, the polluted soil in the tested soil area is collected for small-scale experiments, so that the pollution characteris