准东煤田露天矿区降尘、土壤重金属分布特征及生态风险评价

    Heavy metals distribution and ecological risk assessment of dust and soil in opencast mine of east Junggar basin in Xinjiang

    • 摘要: 本文以准东煤田露天矿区降尘、土壤中Zn、Cu、Cr、Pb、Hg、As 6种重金属元素为研究对象,采用污染负荷指数法、地质累积指数法、潜在生态危害指数法对其进行生态风险分析。结果表明:研究区降尘重金属含量普遍高于土壤重金属,As为超标最严重元素,Pb为超标最轻微元素,且不存在生态风险;Cr、Hg、As为降尘、土壤中生态风险都较高的元素,降尘重金属生态风险较土壤更为严峻,相关分析表明Zn、Cu、Cr具有良好的伴生性,燃煤是As的主要来源;研究区内大气-土壤重金属污染元素主要为Cr、Hg、As,其他元素应做好防范工作。

       

      Abstract: The opencast mine of east Junggar basin in Xinjiang is the largest self-contained coalfield in China, the ecological environment of the opencast was very fragile because of its arid climate and poor soil. In this study, 50 soil and dust samples in opencast mine were collected in order to explore the heavy metals spatial distribution and different between soil and dust of the coal mining. The content of zinc (Zn), copper (Cu), chromium (Cr), lead (Pb), mercury (Hg) and arsenic (As) were measured and the ecological risk was assessed by pollution load index, geo-accumulation index and potential ecological risk index. Results showed that the content of dust heavy metals was higher than soil generally, As were exceeded the standard limited most seriously, Pb were most slight and has no ecological risk. Ecological risk of Cu,Cr,Hg were both higher in soil and dust,but dust face more severe ecological risk. Correlation analysis showed that Zn,Cu,Cr may the associated elements and As may come from coal combustion. The main contamination elements were Cr,Hg and As in study area,and others elements prevention should be considered.

       

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