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为了判别地球化学材料在土壤改良与重金属修复中的作用,本研究以江西龙南某地被稀土采矿废水污染而废弃的农耕地为对象,用黏土矿物等材料组成的三种修复方案对249 km2的废弃地进行修复。一周期后,比较修复前后土壤中重金属生物易迁移态的变化来评价该技术的有效性。结果表明,该地Pb超标程度最重,达101.50 mg·kg-1。Cd、Hg、As次之,分别为0.13 mg·kg-1、0.13 mg·kg-1、2.98 mg·kg-1,均超赣州市土壤背景值含量,超龙南地区土壤Pb的均值,修复目标为Pb。该地土壤中Pb的易迁移态含量与总量不显著相关。经地球化学工程技术修复后,Pb易迁移态降低了3.25%,修复效果明显。一周期后,Pb的易迁移态平均降幅为1.40%,修复效果稳定。修复效果最佳的方案C能使Pb降低幅度达到3.38 mg·kg-1,在经济上体现为最廉价,体现了地球化学工程技术的优势。
In order to distinguish the role of geochemical materials in soil improvement and heavy metal remediation, this study aimed to study the farmland contaminated by rare earth mining wastewater in a place in Longnan, Jiangxi Province. Three rehabilitation programs consisting of clay minerals and other materials were used to study the effects of geochemical materials Abandoned for repair. After one cycle, comparing the changes of heavy metal bio-migratory in the soil before and after the restoration to evaluate the effectiveness of the technology. The results showed that the highest level of Pb exceeded 101.50 mg · kg-1. Followed by Cd, Hg and As were 0.13 mg · kg-1, 0.13 mg · kg-1 and 1.98 mg · kg-1, respectively, which were all beyond the background values of soil in Ganzhou City, For Pb. The content of Pb in soils was not significantly correlated with the total amount. After geochemical engineering and technology restoration, Pb migration is reduced by 3.25%, and the repair effect is obvious. After one cycle, the average migration rate of Pb decreased by 1.40%, and the restoration effect was stable. The best solution C can reduce Pb by 3.38 mg · kg-1, which is cheapest in economy and shows the advantages of geochemical engineering.