摘要
采集湖南郴州某典型铅锌矿区废弃地植物修复客土层(0~30 cm)及污染土层(30~50 cm)土壤,测定土壤中Cd、Cr、Cr^(6+)、Cu、Ni、Pb、As和Hg的含量;采用地累积指数法、内梅罗指数法和潜在生态风险指数法对土壤中重金属的含量及污染程度进行定量评价;并通过BCR连续分级提取法分析重金属的形态.结果表明,客土的As含量以及污染土的Pb和As含量均远超出"土壤环境质量建设用地土壤污染风险管控标准(试行)-GB36600—2018"中第二类用地筛选值.对重金属含量和污染程度的评价结果表明,试验土壤主要以Pb和As污染为主,污染土中Cd、Cu、Pb和As的污染程度均高于客土.土壤中Cd和As的生态风险系数较高,最高分别达到了22.96和568.57.Cd和As是研究区域中土壤重金属潜在生态风险的主要贡献者;BCR结果表明,Cd在客土和污染土中均具有最高的生物有效性,酸可溶态Cd的最高占比达到31.9%.污染土和客土之间的混掺,污染土中活性金属向客土层的迁移以及植物根系分泌物的螯合作用都是导致客土层土壤中重金属总量和生物有效性增加的原因.本研究结果可为铅锌矿区废弃地重金属污染治理提供参考.
The polluted soil(30~50 cm) and the guest soil(0~30 cm) of the typical abandoned lead-zinc mine area were collected in Chenzhou, Hunan Province. The concentrations of Cd, Cr, Cr^(6+), Cu, Ni, Pb, As and Hg in soil were determined. The concentration and pollution degree of heavy metals in soil were quantitative evaluated by the Geoaccumulation index, Nemerow index and Potential ecological risk index methods. The metal fractions were analyzed by sequential extraction of BCR. The results indicated that the concentration of As in the guest soil and Pb and As in the polluted soil exceeded the land screening values of Chinese National Soil Pollution Standard(GB36600—2018). The evaluation indexes showed that the soils were mainly polluted by Pb and As, and the pollution degree of Cd, Cu, Pb and As in polluted soil was higher than that in guest soil. The potential ecological risk coefficients of Cd and As in the soils were the highest, with the highest values reaching 22.96 and 568.57, respectively. Cd and As were the major contributors to the potential ecological risks of heavy metals in the study area. The results of BCR indicated that Cd had the greatest bioavailability with the highest acid-soluble fraction reaching to 31.9% of the guest soil and polluted soil. The mixing between polluted soil and guest soil, the up-migration of active metals from polluted to guest soil layer and the chelation of plant root exudates are the reasons of the increase of the total concentration and bioavailability of heavy metals in the guest soil. The results bring new insights into the remediation of heavy metal pollution in the abandoned mine area.
作者
阮敏
周康
黄忠良
李辉
张轩
吴子剑
覃晓莉
吴希锴
黄兢
RUAN Min;ZHOU Kang;HUANG Zhongliang;LI Hui;ZHANG Xuan;WU Zijian;QIN Xiaoli;WU Xikai;HUANG Jing(School of Energy and Power Engineering,Changsha University of Science&Technology,Changsha 410114;State Key Laboratory of Utilization of Woody Oil Resource,Hunan Academy of Forestry,Changsha 410004)
出处
《环境科学学报》
CAS
CSCD
北大核心
2021年第9期3803-3814,共12页
Acta Scientiae Circumstantiae
基金
国家自然科学基金青年项目(No.51808216,51608052)
湖南省自然科学基金青年项目(No.2019JJ50665)
长沙市科技计划国际合作项目(No.kq1907082,kq1801027)
湖南省林业科技计划项目(No.XLK201908,XLK201938)
湖湘青年英才计划项目(No.2018RS3109)。
关键词
矿区废弃地
客土
重金属
BCR
abandoned mine area
guest soil
heavy metals
BCR
