The impact of plant growth on cadmium-contaminated soil after remediation by two stabilization materials

The risk of cadmium (Cd) re-release from soil remediated under plant growth conditions varies with different stabilizing materials. Pot experiments were conducted to evaluate the degree of Cd leaching and the plant Cd content in cadmium-contaminated soil remediated with aluminate and silicate materials under plant growth conditions. The result showed that at 30 days of the experiment, the germination rate of tall fescue in the soil repaired by both silicate and aluminate materials was higher than that of the control group, and the Cd content in plants treated by silicate materials was better than that of aluminate. In the treatments without tall fescue, silicate and aluminate materials made the leaching concentration of Cd decrease from 27.83 μg/L to 22.67 μg/L and 12.97 μg/L, respectively, indicating that aluminate had a better stabilization effect on Cd. Under tall fescue cultivation, the Cd leaching concentration exhibited a slight increase. By analyzing soil enzyme activity, it was found that in the treatments with and without tall fescue, silicate materials reduced the total soil enzyme activity by 35.73% and 22.58%, respectively, while aluminate materials increased it by 19.93% and 18.71%, respectively. This indicated that aluminate had a positive impact on soil biochemical properties. In conclusion, Cd-contaminated soil remediated with aluminate materials exhibits a lower risk of re-release, and thus aluminate materials are suitable for Cd-polluted sites where vegetation may grow after remediation.