Effects of amendments on heavy metal immobilization and uptake by Rhizoma chuanxiong on copper and cadmium contaminated soil

An improved method was applied for remediating cadmium and copper co-contaminated soil and reducing the metal concentration in Rhizoma chuanxiong. Pot experiments were conducted with six amendments (composed with bentonite, phosphate, humic acid, biochar, sepiolite powder, etc.). The results showed that soil pH, biological activities (soil enzymatic activities and microbial counts) and R. chuanxiong biomass were greatly improved with the addition of amendments in all treatments, especially in T3 and T6. Also, amendments effectively decreased the concentration of malondialdehyde and H2O2 in R. chuanxiong. In the T3 treatment, the bio-available Cd and Cu in soil were significantly decreased by 0.53 and 0.41 mg kg(-1), respectively. Meanwhile, the amendment in T3 reduced Cd and Cu accumulation in R. chuanxiong about 45.83 and 39.37%, respectively, compared to T0. Moreover, the Fourier transform infrared spectroscopy spectra showed the surface functional groups of every amendment. To conclude, this study offers an effective and environmental method to reduce metal accumulation in R. chuanxiong on heavy metal co-contaminated soil.