Effect of Growth Medium on Cd,Pb,Zn Accumulation by Brassica juncea

Soil and sand pot experiment was carried out to study the effect of two types of growth medium-soil and sand on accumulation of Cd,Pb and Zn in Brassica juncea under the conditions of the exogeous Cd,Pb and Zn combined pollution. The results showed that the accumulations of Cd,Pb,Zn in Brassica juncea were all significantly correlated with their concentrations in the soil or sand,respectively. The concentrations of Cd,Pb,Zn accumulated in Brassica juncea growing in the sand were markedly higher than those in soil culture. The maximum concentrations of Cd,Pb,Zn in shoot from the sand culture were 311.3,366.7,2 760 mg/kg,and were 14.4,12.9 and 9.02 folds compared with that in the soil culture. The Cd,Pb,Zn extraction by Brassica juncea in sand culture were higher than those in soil culture,and were 1.29~8.96,1.02~8.58 and 1.68~5.62 folds compared with that in the soil culture.The accumulation factors of Cd,Pb and Zn in sand culture were significantly greater than those in soil culture,and followed the rank of CdZnPb (Pb accumulation fatcor1). It can be concluded that Brassica juncea appeared to be strong Cd and Zn accumulator,but less capability to accumulate Pb. In general,very low bioavailability of Cd,Pb,Zn in soil directly restricts the remediation effect.