焦作演马煤矿区土壤重金属空间分布与污染评价

Spatial Distribution and Pollution Assessment of Heavy Metals in Soil from Yanma Coal Mine in Jiaozuo

目的:研究煤矿区土壤重金属空间分布特征及污染状况。方法:利用电感耦合等离子体质谱法(ICP-MS)对焦作演马煤矿矸石灰及周边表层土壤Cd、As、Pb、Cr、Cu、Zn等6种重金属含量进行测定。结果:研究区内表层土壤重金属含量Zn>Pb>Cr>Cu>As>Cd。除Cr、As外,其余重金属含量平均值都高于河南省土壤元素背景值,呈现不同程度的累积。表层土壤水平空间分布与矸石堆的距离密切相关,在一定范围内重金属含量随距离增加而降低。各重金属元素潜在生态危害指数Cd>Pb>As>Cu>Cr>Zn,综合潜在生态危害指数RI值为109.97~490.67,Cd对RI值的贡献为87.78%。结合相关性分析与聚类分析,推断Pb、Cr、Cu与农业活动和交通运输相关,Zn源于采煤活动与居民生活,As来自农业生产,Cd受采煤活动和农业生产影响。结论:演马煤矿区土壤重金属污染水平整体较轻,风向是影响重金属水平空间迁移的主要因素,Cd为主要的污染物和潜在生态风险因子。土壤重金属污染主要受采煤活动、农业生产、居民生活、交通运输的影响。

Objective:To understand the spatial distribution and pollution of heavy metals in soil in coal mining areas.Methods:The concentrations of Cd,As,Pb,Cr,Cu and Zn from gangue ash and surface soil samples from Yanma coal mine in Jiaozuo city were determined by the inductively coupled plasma mass spectrometry(ICP-MS).Results:The results showed that the average ranked concentrations of six metals in the surface soils were Zn>Pb>Cr>Cu>As>Cd,and the average values were higher than the background values of soil elements in Henan Province except Cr and As.The concentration of heavy metals in surface soils decreased to some degree with distance gangue dump.The potential ecological risk index(RI)of heavy metals was Cd>Pb>As>Cu>Cr>Zn rankly,and the comprehensive index ranged from 109.97 to 490.67,which belonged to moderate or considerable potential ecological risk.The contribution rate of Cd to RI was 87.78%,indicating that Cd was the main potential ecological risk factor.Combined with correlation and cluster analyses,heavy metal contamination of soils at the Yanma coal mine area was mainly affected by coal mining,agriculture,residential life and traffic.The sources of Pb,Cr and Cu were related to agricultural activities and traffic,whereas Zn was controlled by coal mining and residential life.As pollution source was shaped by agricultural production,Cd was influenced by coal mining and agricultural production.Conclusion:Together,the results provide the profound insight into the relationship between heavy metal pollution and human activities,and scientific bases for ecological risk assessment and prevention of heavy metal pollution in coal mining areas.