承德黑山钒钛磁铁矿矿集区土壤重金属空间结构特征与生态风险评价

Spatial Structure Characteristic and Ecological Risk Assessment of Heavy Metal in the Soil of Vanadium Titano-magnetite Mine Area in Heishan,Chengde,North China

矿区土壤重金属来源、空间分布特征对矿山周围的生态环境脆弱区土壤环境保护、修复以及生态风险评价具有重要意义。本文以承德市隆化县韩麻营镇黑山钒钛磁铁矿所在小流域为研究区,利用地累积指数法、内梅罗污染指数法验证矿区周围土壤重金属污染程度,利用潜在生态危害指数法对土壤重金属的生态环境风险做了全面评价,利用变异函数、相关性分析、金属元素主成分和聚类分析等方法明确了研究区重金属来源及空间分布特征。研究结果表明:研究区土壤中重金属元素Mn、Ti、V、Zn、Co、Cu、Mo、Cd和SOM的平均含量均高于河北省背景值;重金属元素As、Cr、Ni、Sb、Pb的平均含量均略低于河北省背景值;土壤重金属元素的空间分布十分均匀。研究区大量土壤重金属元素为轻度污染,少量为中度污染,只在极少量的局部地区土壤重金属元素Ti、Cu、Co、Hg、Cr显示出重污染特性。研究区整体处于较清洁水平,并且研究区土壤重金属元素高值点主要分布在矿区周围和人类活动区域,钒钛磁铁矿矿区及其伴生矿物和人类生产活动对重金属元素含量分布有较大影响。

The source and spatial distribution characteristics of heavy metal in the soil of mining areas are of great significance for soil environmental protection,restoration and ecological risk assessment in the fragile ecological areas around mines.The spatial distribution characteristics of heavy metal in the soil samples of vanadium titano-magnetite had been analyzed in Heishan,Hanmaying town,Longhua county,Chengde.Nemero pollution index and igeo index of geo-accumulation had been used to analyzed pollution level of heavy metal of the vanadium titano-magnetite.The potential ecological harm index method had been used to comprehensively evaluate the ecological environmental risk of heavy metal in the study area,and the sources and spatial distribution characteristics of heavy metal were identified by means of variogram,correlation analysis,metal element principal component analysis and cluster analysis,The results showed that the average contents of Mn,Ti,V,Zn,Co,Cu,Mo,Cd and SOM in the soil in the study area were all higher than the background values in Hebei Province;The average contents of As,Cr,Ni,Sb and Pb were slightly lower than the background values in Hebei Province;and the spatial distribution of heavy metal elements in the soil was very uniform.Most of the soil in the study area is slightly polluted and a small amount is moderately polluted.Only a small amount of soil heavy metal elements Ti,Cu,Co,Hg and Cr in the local area show heavy pollution characteristics.The study area is generally relatively clean,the sampling points seriously polluted by heavy metal were mainly distributed around the mining area and the human activity area.The vanadium titano-magnetite,its associated minerals and human production activities have a great influence on the content distribution of heavy metal elements.