贵州煤矿区表层土壤微量重金属污染风险评价

Study on Trace Heavy Metals Risk Assessment in Surface Soils of Coal Mine Area,Guizhou Province

文章研究了贵州省金沙县新化乡煤矿地区煤矸石的堆放对周边表层土壤重金属的影响。以煤矸石堆为中心,采集堆放时间大约为30、15、6 a的煤矸石堆附近土壤样品,并分析测定土壤的p H值和具有环境意义的8种微量重金属元素Cr、Cu、Zn、Cd、Pb、Ni、V、Co的含量。采用累积强度、内梅罗污染指数及污染负荷指数来探讨土壤受重金属污染的程度,通过相关性分析、主成分分析和聚类分析,确定土壤中主要的重金属污染物及其关系。研究结果表明,3个研究区域土壤均呈酸性,且距煤矸石堆越近,土壤酸性越强,除Cd和Pb外土壤中其它微量重金属的含量均超出贵州省土壤环境背景值。以远离矿区土壤中重金属含量为累积强度标准,发现3个研究区域土壤中除Pb和Co外其他重金属均发生了不同程度的累积,土壤中主要的重金属污染物为Cu、Cr、Ni、V。3个研究区域土壤均受到重金属污染,污染程度为轻度污染,土壤受重金属污染程度与距煤矸石堆的距离呈负相关、煤矸石的堆放时间呈负相关。该结论将为贵州省煤矿地区煤矸石的综合治理提供科学依据。

This paper studied the impact of gangue on the heavy metal content of surrounding surface soil in coal mine area of Xinhua, Jinsha County, Guizhou Province. Soil samples were collected around the gangue heaps which had been piled up for approximately 30 years, 15 years and 6 years, then the p H and eight heavy metals with environmental significance(Cr,Cu, Zn, Cd, Pb, Ni, V and Co) of soils were analyzed and determined. The potential hazards of heavy metals were analyzed by nemerow integrated pollution index(PN) and pollution load index(PL Ⅰ).The main heavy metal pollutants and their relationships were determined by correlation analysis, principal component analysis and cluster analysis. The results showed that the soils in the three studied region were acidic. Moreover, the closer distance from the gangue heap, the more acidic soils were found. Except for Cd and Pb, the concentrations of other heavy metals in the soil samples of the three studied region exceeded the soil environmental background values of Guizhou Province. Compared with the soils away from mining area, the study found an accumulation of heavy metals except for Pb and Co in varying degrees in the studied soils. From the assessment results, the main heavy metal pollutants in soils are Cu, Cd, Ni and V. The soils in the three region have been polluted by the heavy metals and their contamination levels are mild. The study also found that the extent of soil contamination by heavy metals was negatively correlated with the distance away from the gangue, the time that the gangue was piled up.The conclusion will provide scientific basis in coal mine environmental pollution control and protection.