香根草及添加剂对模拟降雨条件下汞污染土壤和矿渣地表径流中汞含量的影响

Mitigation effects of Vetiveria zizanioides and additives on surface runoff mercury concentration from mercury-contaminated soil and slag under simulated rainfall

通过盆栽试验,模拟降雨研究香根草（Vetiveria zizanioides）及添加剂（木屑、腐殖土）对汞污染土壤和汞矿渣中汞通过地表径流向周围迁移的影响,结果显示：（1）颗粒态汞占地表径流总汞的80%以上,是汞进行迁移的最主要途径。（2）在汞污染土壤中直接种植香根草,或者将香根草分别与木屑或腐殖土结合,能有效减少地表径流中的总汞（63%~85%）、颗粒态汞（63%~85%）和可溶态汞（27%~73%）向周围环境迁移,其效果显著高于直接在污染土壤中添加单一的木屑（5%）或腐殖土（23%）。（3）在矿渣中直接添加低汞土壤或木屑、或直接种植香根草,或将香根草分别与低汞土壤、木屑、腐殖土结合均能有效固定矿渣中的总汞（29%~82%）、颗粒态汞（27%~84%）和可溶态汞（20%~70%）。

A pot experiment with simulated rainfall was conducted to study the mitigation effects of Vetiveria zizanioides and additives（sawdust and humus soil） on the surface runoff mercury concentration from Hg-contaminated soil and slag.In the surface runoff,particle mercury accounted for 80% of the total mercury,being the leading form of mercury transported to environment.Planting V.zizanioides on the Hg-contaminated soil or applying V.zizanioides mixed with sawdust or humus soil into the contaminated soil could effectively reduce the total mercury,particle mercury,and dissolved mercury transportation to environment by 63%-85%,63%-85%,or 27%-73%,respectively,and the effect was significantly higher than that of applying single sawdust（5%） or humus soil（23%） into the contaminated soil.Applying background soil or sawdust into the Hg-contaminated slag,planting V.zizanioides on the slag,or applying V.zizanioides mixed with background soil,sawdust,or humus soil into the slag could effectively fix the total mercury,particle mercury,and dissolved mercury in slag by 29%-82%,27%-84%,or 20%-70%,respectively.