关键词: 钝化剂；土壤, 有效态重金属；铅；镉；小白菜；生物富集

Abstract: This study is to research effects of different passivating agents on the available Cd and Pb contents in soil and their accumulation in plants,and select the passivating agents with better passivating effect on Cd and Pb polluted farmland,which will provide a theoretical reference for the passivated remediation of heavy metals in situ. Took soil without passivating agent as control,and selected bentonite,calcium carbonate and biomass carbon as the passivators, with the designed addition amounts in soil of 0.5%,1.0%,2.0% and 5.0% respectively to conduct indoor pot experiment on pakchoi seedlings.The results showed that,calcium carbonate had better passivating effects on soil available Cd and Pb at the additive amounts of 5.0% and 2.0%,and the soil organic matter content was positively correlated with the soil available Cd and Pb content. After calcium carbonate was added for 45 days,the contents of Cd and Pb in the stems and leaves of pakchoil decreased by 59.3% and 57.1% compared with control.The passivating agents could inhibit the uptake and transport of Cd and Pb by pakchoi. Calcium carbonate and biomass carbon had better controlling effects on the Cd and Pb absorption and transport in the middle and later growth stage of pakchoi.Adding 2.0% calcium carbonate had the best passivating effects on soil available Cd and Pb,and calcium carbonate and biomass carbon presented stronger inhibition on Cd and Pb absorption and transport in the stems and leaves of pakchoi.

Key words: Passivating agent, Soil, Available heavy metal, Cd, Pb, Pakchoi, Biological concentration