大环江流域重金属污染土壤的3种修复技术研究

摘要

In this thesis, three kinds of remediation technologies (planting Sedum alfredii, planting Pteris vittata, and plant-ing Pteris vittata combined with applying chemical activator ) for the heavy-metal-contaminated soil in the Dahuanjiang River ba-sin of Guangxi were researched, the heavy metal contents in the soil and plants before and after the remediation were measured , and the remediation effect and heavy-metal-enrichment characteristics of various plants were compared .The main research results were obtained as follows:planting Sedum alfredii in maize field could reduce Cd content in the soil by 12.23%, and also could re-duce the content of Zn, Pb and Cd in maize;the enrichment coefficient of Sedum alfredii to Cd was 5.82, so this plant had a bet-ter remediation effect on the Cd-contaminated soil;after interplanting Pteris vittata in mulberry field, the content of Pb and As in the soil was decreased by 12.57%and 11.82%, respectively, and that in the mulberry leaf was reduced by 28.09%and 14.81%, respectively;the enrichment coefficient of Pteris vittata to Pb and As was 1.05 and 1.45, separately, indicating this plant had an obvious removing effect on Pb and As in the soil; after interplanting Pteris vittata combined with applying chemical activator in mulberry field, the removal efficiency for Cu, Zn, Pb, Cd and As in the soil was improved obviously, the content of these heavy metal elements in the mulberry leaf was decreased to a certain extent , and the enrichment coefficient of Pteris vittata was increased somewhat, showing the application of chemical activator could improve the absorption of Pteris vittata to heavy metal elements in the soil.%以大环江流域重金属污染土壤为研究对象，分别采用东南景天、蜈蚣草、蜈蚣草联合活化剂3种方法进行土壤重金属修复，测定了修复前后土壤重金属和植物中重金属含量，研究了各富集植物的修复效果和富集特征，结果表明：东南景天修复玉米地后，土壤中镉的去除效率达12．23％，玉米中的锌、铅、镉含量均有所降低，东南景天对镉的富集系数为5．82，说明东南景天在修复镉污染土壤的效果较好；在桑树地中套作蜈蚣草，铅、砷的去除效率分别达到12．57％、11．82％，桑叶中的5种重金属含量均有所降低，其中铅、砷含量比未套作前分别降低了28．09％和14．81％，蜈蚣草对铅与砷的富集系数分别为1．05、1．45，说明蜈蚣草对土壤中铅、砷具有明显的去除效果；在桑树与蜈蚣草套作地中施加化学活化剂后，土壤中5种元素的去除效率均有明显的提高，桑叶中5种元素的含量均有所下降，蜈蚣草的富集系数均有所上升，说明活化剂的施用能增加蜈蚣草对重金属元素的吸收。