Abstract: In order to reveal the release characteristics of heavy metals and the stabilization effect of biochar in lead-zinc mine soil under acid rain leaching condition，the physicochemical properties and leaching characteristics of Pb,Zn,Cd and As in soil without biochar,soil with rice straw biochar and corn straw biochar were studied by soil column leaching experiment and emphatically analyzed stabilization effect of the two biochar.The results showed that the soil in lead-zinc mine area had a strong buffer capacity to acid,the pH value of leachate ranged from 6.5 to 8.3,while the addition of alkaline biochar had no obvious effect on it.However,the EC and TDS at the beginning of leaching were significantly increased.The leaching of Pb,Zn,Cd and As was affected by different biochar.The addition of corn stalk biochar significantly reduced the content of Pb in leachate,and its cumulative outflow decreased by 49.11%.But it significantly promoted the release of Cd and Zn.Rice straw biochar accelerated the release of Pb in soil,while it had no significant effect on Zn and Cd.Both biochar activated As in soil.

Key words: lead zinc ore, simulated acid rain, biochar, heavy metal