贵州遵义锰矿区植物根际土壤中重金属形态迁移转化及风险评价  

Heavy metal speciation migrationtransformation and risk assessement in plant rhizosphere soil of Zunyi manganese mineland, Guizhou

作　　者：程俊伟 蔡深文[1] 黄明琴[1] 颜雄[1] CHENG Junwei;CAI Shenwen;HUANG Mingqin;YAN Xiong(Zunyi Normal University,Zunyi,563006,China)

机构地区：[1]遵义师范学院,遵义563006

出　　处：《环境化学》2022年第9期2833-2841,共9页Environmental Chemistry

基　　金：贵州省教育厅青年科技人才成长项目(黔教合KY字[2019]116,黔教合KY字[2019]110);贵州省黔北土壤资源与环境特色重点实验室(黔教合KY字[2017]010号,KLSREQ2018005)资助。

摘　　要：通过野外采样与系统监测分析方法,研究了贵州遵义锰矿区优势植物及根际土壤中重金属含量、赋存形态及迁移转化相关性,并分别利用潜在生态风险指数法(RI)和风险评价指数法(RAC)对土壤污染特征和重金属生物有效性进行了评价.结果表明,研究区内Mn在野艾蒿、苎麻、酸模叶蓼和垂序商陆等植物生长区域含量分别超过背景值1.03—7.06倍,累积差异显著;Cd、Zn和Cr在小蓬草和垂序商陆根际区域存在显著性累积污染;根际环境中Mn、Pb主要以可还原态赋存,且受环境pH影响明显,Cu、Cd、Zn和Cr主要以氧化态和残渣态形式赋存,小蓬草和酸模叶蓼对Cd和Zn的吸收转化过程使根际土壤中Cd、Zn的生物有效性提升率达72.61%;植物体内Mn、Pb、Zn、Cr和Cd含量与根际土中相应元素的酸可提取态、可还原态和残渣态间部分呈显著正相关(P<0.05),存在生物协同关联;根际土壤综合潜在生态风险指数评价显示Cd的很强和极强生态风险等级样本数占比分别达38.89%和11.11%,是该区域土壤潜在生态危害程度最大的元素;风险评价指数趋势为Mn>Pb>Zn>Cr>Cd>Cu,Mn、Cd、Pb、Cu和Zn分别在小蓬草、垂序商陆和酸模叶蓼等根际土壤中表现为极高、高或中风险等级,受富集型植物吸收转化影响显著.A field sampling and systematic analysis were carried out in Zunyi Manganese mineland,Guizhou. The heavy metal concentrations in the main dominant plants and their associated rhizosphere soils were determined to evaluate the relationships between the heavy mental speciation in the soils and transformation rates in the plants. The heavy metal contamination and bioavailability of Mn mineland were assessed with the potential ecological risk index(RI) and risk assessment index code(RAC). The results showed the following: Mn concentrations in the rhizosphere soils of Artemisia lavandulaefolia, Boehmeria nivea, Polygonum lapathifolium and Phytolacca Americana were very high, being 1.03—7.06 times of the background value, respectively. The rhizosphere soils of Conyza canadensis and P. Americana were significantly contaminated by Cd, Zn and Cr. Mn, Pb mainly existed as the reducible forms in the rhizosphere soils, which were significantly affected by soil pH. Cu, Cd, Zn and Cr mainly existed as the oxidable and residual forms. Cd and Zn transformation in C.canadensis and P. lapathifolium significantly increased the bioavailability of Cd and Zn in the rhizosphere soils, reaching about 72.61%. The significant positive correlations were observed between Mn, Pb, Zn, Cr and Cd concentrations in the plant tissues and their extractable and reducible and residual forms in the associated rhizosphere soils(P < 0.05), demonstrating synergistic correlations between organisms. The potential ecological risk index(RI) in the rhizosphere soils showed that Cd was the element with the highest potential ecological risk in Mn mineland, and its high and severely high ecological risk accounted for 38.89% and 11.11%, respectively. The order of the risk assessment index code was Mn > Pb > Zn > Cr > Cd > Cu. Mn, Cd, Pb,Cu and Zn in the rhizosphere soils of C. canadensis, P. americana and P. lapathifolium were extremely high, high or medium risk levels, which were significantly affected by absorption and transformation of the accumulated plants

关 键 词：锰矿区 重金属 赋存形态 生物有效性 风险评价 

分 类 号：X820.4[环境科学与工程—环境工程] X53