北京市密云水库上游金铁矿区土壤重金属污染特征及对比研究

不同金属矿山选冶活动造成的矿区及周边土壤中重金属的分布累积特征不同.为了解密云水库上游金矿和铁矿矿区土壤中重金属地球化学特征的异同及污染状况,对区域内典型的金矿和铁矿矿区进行土壤样品采集,应用地球化学方法研究了2种土壤中重金属的污染特征,并应用地累积指数法评价了其污染状况.结果表明,2种土壤中除As外的其它重金属含量明显高于北京市土壤重金属背景值,金矿矿区土壤重金属含量普遍高于铁矿矿区.相关性分析表明,金矿矿区土壤中Cu含量与Pb、Zn(p<0.01)及Cr、有机质(OM)含量(p<0.05)之间显著相关,pH值与Pb含量(p<0.01)及Hg含量(p<0.05)呈显著负相关,而铁矿矿区土壤中重金属含量之间的相关性不显著.金矿尾砂中重金属含量明显高于铁矿尾砂,与矿区土壤污染状况一致.地累积指数法评价结果显示,金铁矿区土壤中重金属的污染程度均已十分严重,金矿矿区土壤污染程度高于铁矿,金矿矿区土壤重金属的污染程度由高到低依次为:Pb>Hg>Cd>Cr>Cu>Zn>Co>As;铁矿矿区土壤重金属的污染程度由高到低依次为:Pb>Cd>Cr>Co>Cu>Zn>Hg>As.该研究数据可为同一区域内不同金属矿区重金属污染的有效监控与治理提供科学依据.

Pollution characteristics and their comparative study of heavy metals in the gold and iron mine soil of the upstream area of Miyun Reservoir, Beijing

The distribution and cumulative characteristics of heavy metals in different mines and surrounding soil caused by ore dressing and smelting activities were different. In order to investigate the geochemical characteristics and pollution status of heavy metals in the upstream areas of Miyun Reservoir, the soil samples from typical gold and iron mines were analyzed by the geochemical method and the Geoaccumulation Index was used to evaluate the pollution status of heavy metals. The results showed that, the metal concentrations in the Gold and Iron mine soil samples exceeded the background levels in Beijing except for As, and the content of heavy metal in gold mine soil was higher than that of iron mine soil. Moreover, correlation analysis indicated that significant correlations existed among Pb, Zn (p<0.01), Cr, OM (p<0.05) and Cu, while significant negative correlations existed among Pb (p<0.01), Hg (p<0.05) and pH in gold mine soil. There were no significant correlations among metals in iron mine soil. In addition, heavy metals in gold mine tailings were significantly higher than those in iron ore tailings, which was consistent with the soil pollution status in mines. The Geoaccumulation Index suggested that heavy metals in both soil samples were very serious and the pollution degree of gold mine was higher than that of iron mine. The pollution degrees of gold mine soil samples was ordered as Pb>Hg>Cd>Cr>Cu>Zn>Co>As, while Pb>Cd>Cr>Co>Cu>Zn>Hg>As for iron mine soil samples. The results can provide scientific basis for the effective monitoring and management of heavy metal pollution in different metal mines within this region.