遵义松林Ni-Mo矿区耕地土壤铊污染及潜在生态风险初步评价

贵州遵义松林Ni-Mo矿区为华南下寒武统黑色页岩Ni-Mo矿化带中的典型矿区之一,对由其矿产资源开采活动引起的土壤环境质量评价具有重要的科学及实际意义。本研究以遵义松林Ni-Mo矿区耕地土壤为研究对象,采用ICP-MS分析土壤中铊的含量。分析结果显示,矿区耕地土壤中铊平均含量为1.84mg/kg,明显高于贵州土壤表层铊元素背景值,初步认为矿区黑色页岩、Ni-Mo矿体、开采暴露于地表的尾矿及围岩碎石为矿区耕地土壤铊的来源。运用地质累积指数和潜在生态危害指数分别对耕地土壤铊污染程度和潜在生态风险进行了初步评价,结果表明:研究区耕地土壤已遭受铊污染,其污染程度评价等级可达中度-重污染;部分样品的潜在生态风险评价等级为中等,显示该区耕地土壤存在潜在生态风险,值得开展进一步的土壤铊污染修复研究。

Preliminary Assessment on Contamination and Potential Ecological Risk of Thallium in Cultivated Soils around the Ni-Mo Mining Area in Songlin, Zunyi

The Ni-Mo mining area in Songlin,Zunyi,Guizhou,is a typical one within the lower Cambrian Ni-Mo mineralization zone of South China.Therefore,assessing the environmental quality of soils around the mining area is of important scientific and practical significance.The concentrations of thallium in the cultivated soils around the Ni-Mo mining area in Songlin were analyzed by inductively coupled plasma mass spectrometry(ICP-MS) in this study.The result shows that the thallium contents(with an average of 1.84 mg/kg) in the soils are higher than the background value of thallium in the topsoil of Guizhou Province.It is preliminarily suggested that the black shales,Ni-Mo ores and Ni-Mo tailings exposed on the surface environment are major sources of thallium in the soils.In the present study,we evaluated the degree of contamination and potential ecological risk of thallium in the soils in terms of geoaccumulation index and potential ecological risk index,respectively.It is revealed that the soils around the Ni-Mo mining area in Songlin,Zunyi,Guizhou,have been contaminated by thallium(most of the samples with slight to moderate heavy pollution levels).It is also indicated that the studied soils have an obvious potential ecological risk caused by thallium(with low to moderate potential ecological risk levels).Therefore,further research on remediation for the contaminated soils deserves to be carried out.