典型铜镍矿区周围环境介质中重金属及其化学形态分布特征

重金属污染是金属矿山开采和冶炼所引起的主要环境问题。对甘肃省典型矿业城市金昌市周围农田土壤、废渣堆表面风化物及降尘、尾矿坝尾矿砂和尾矿坝旁排污沟沉积物中Cr、Cu、Ni、Pb、Zn含量及其化学形态进行分析。结果表明:不同区域环境中重金属呈现不同程度累积,其中以Cu、Ni最为显著,含量由高到低依次为尾矿坝排污沟>尾矿坝>废渣堆>农田土壤;尾矿砂和沉积物中重金属分布以Ni含量显著高于Cu含量为特征;而农田土壤和风化物及降尘中重金属分布以Cu含量高于Ni含量为特征,前者Cu、Ni主要来源于尾矿,后者与冶炼烟尘排放有很大关系;样品中除Cr、Zn以残渣态为主外,Cu、Ni、Pb化学形态分布有较大差异,Cu以可氧化态和残渣态为主,Ni以可还原态为主,其次为弱酸提取态,Pb以可还原态为主,其次为残渣态。土壤理化性质是影响重金属化学形态分布的重要因素。

Chemical Speciation and Distribution of Heavy Metals in Different Environmental Mediums Around Ni-Cu Mine Area

The contamination by heavy metals is a major environmental problem in urban areas near mines.The heavy metals(Cr,Cu,Ni,Pb and Zn) in various environmental mediums around a Ni-Cu mine in the City of Jinchang,Gansu Province,were analyzed using ICP-AAS.These mediums include the cultivated soils,the weathering and atmospheric deposition on waste slagheap surface,the tailings,and the sludge in the drainage ditch by the tailings.The results showed that the heavy metals in various mediums were mainly Cu and Ni,and those concentrations were,in the descending order,in ditch,tailings,slagheap and cultivated soil.In the tailings and the sludge of the ditch,the concentrations of Ni were obviously higher than those of Cu.Whereas,in the soil and the weathering and atmospheric deposition of the waste slagheap surface,the concentrations of Cu were higher than those of Ni.This means that in the first two mediums,Cu and Ni mainly originated from the tailings,while in the latter two mediums,Cu and Ni mainly came from the atmospheric deposition of airborne particles of the smelting.Cr and Zn were mainly in residual fraction,Cu was mainly in oxidizable and residual fraction,Ni was mainly in reducible and acid-soluble fraction,Pb was mainly in reducible and residual fraction.