Abstract: Experiments of bagging in greenhouse were performed to investigate the effect of organic fertiliser, biochar, sepiolite and the mixture of biochar and sepiolite (1∶1) on soil pH and the contents of available Cd and available Pb in heavy metal contaminated soil, and the changes in the cadmium and lead contents of Tetrastigma hemsleyanum roots were analyzed. The results show that the different passivators all increased soil pH in varying degrees, reduced the contents of available Cd and available Pb in soil and reduced the contents of Cd and Pb in Tetrastigma hemsleyanum roots. Compared with the control, the addition of 1% to 5% passivators could increase soil pH value by 0.05 to 1.03, respectively, reduce the contents of available Cd and available Pb in soil by 2.95%-42.46% and 6.21%-55.77%, respectively, and reduce the contents of Cd and Pb in Tetrastigma hemsleyanum roots by 15.61%-48.33% and 8.18%-61.67%, respectively. The addition of 5% of the mixture of biochar and sepiolite had the greatest effect on pH value on the contents of available Cd and available Pb in soil, and on those of Cd and Pb in the Tetrastigma hemsleyanum roots, which indicates that the addition of 5% mixed passivator (the weight ratio of biochar and msepiolite is 1∶1) was the most effective in the passivation remediation of heavy metals in the soil-Tetrastigma hemsleyanum system.

Key words: passivator, Tetrastigma hemsleyanum, available Cd, available Pb