喀斯特地区清虚洞组地层风化对土壤重金属累积的影响

Effects of weathering of Qingxudong formation on heavy metal accumulation in soil in karst area

选择喀斯特地区寒武系清虚洞组地层,研究地层上覆土壤及其剖面中的重金属元素分布特征及来源。采集开阳、松桃、碧江、镇远、台江、凯里、都匀等地的清虚洞组地层上覆土壤样品,利用等离子质谱(ICP-MS)等对土壤的微量元素的含量进行测试分析,以期揭示该地层上覆土壤中的重金属元素分布特征及来源。结果表明:研究区表层土壤样品中Cd、Cr、Cu、Ni、Pb和Zn的平均含量分别为3.46、77.98、34.83、48.66、90.18、562.78mg·kg-1,表现出明显的重金属累积特征,累积程度为Cd>Pb>Zn>Ni>Cu>Cr。土壤剖面中重金属元素呈现底部明显累积Cd、Pb和Zn的特征。研究区土壤中主要累积元素Cd、Pb和Zn的来源与清虚洞组的铅锌矿化密切相关。

To clarify the distribution characteristics and sources of heavy metals in soil weathered from the Cambrian Qingxudong formation in karst area,overlying soil samples,including surface soils and profile soils,were collected from Qingxudong formation in Kaiyang,Songtao,Bijiang,Zhenyuan,Taijiang,Kaili,and Duyun.The concentrations of heavy metals and trace elements in the soils were analyzed by inductively coupled plasma mass spectrometry(ICP-MS).The results showed that the concentrations of Cd,Cr,Cu,Ni,Pb and Zn in surface soils were 3.46,77.98,34.83,48.66,90.18,562.78 mg·kg-1,respectively.Heavy metals in the surface soil showed obvious accumulation characteristics,with cumulative degree of Cd>Pb>Zn>Ni>Cu>Cr.Heavy metals in soil profiles were characterized by significant accumulation of Cd,Pb and Zn at the bottom.The main accumulative elements Cd,Pb and Zn were closely related to the lead-zinc mineralization of Qingxudong formation.