In order to reduce the risk of pollutants entering the human diet from soils via agricultural products

breeding of pollution-safe cultivars (PSCs)

that is

the cultivars whose edible parts accumulate specific pollutant at a low enough level for safe consumption when grown in contaminated soil

has been investigated as a practical method of minimizing the concentrations of heavy metals in crops. In this study

a pot experiment is conducted to investigate the variations of Cd and Pb accumulation in different water spinach cultivars. The results show that: ① shoot biomasses of water spinach don't significantly decrease but increase both under Cd and Pb exposure compared with the controls. This indicates that water spinach has a certain degree of Cd and Pb tolerance

which will increase the health risk from water spinach contaminated by soil Cd and Pb. ② shoot Cd and Pb concentrations vary significantly among the tested cultivars under Cd or Pb exposure (

P

<

0.01) and correlations of Cd and Pb concentrations of all the cultivars between the first and second harvests are significant at

P

<

0.05 level and at

P

<

0.01 level

respectively. ③ The two cultivars

YQ and BGJ

are not only CdPSC but also PbPSC and may be considered as Cd+Pb-PSC. This implies that the characteristics of Cd and Pb accumulations in water spinach are governed by gene(s) and are able to be well reproduced. Therefore

the selection of Cd+PbPSC is feasible in Cd and Pbcontaminated soil.