贵州省典型铅锌矿区土壤重金属污染特征及来源解析

Pollution Characteristics and Source Analysis of Heavy Metals in Soils of a Typical Lead-zinc Mining Area in Guizhou Province

以贵州省丹寨县兴仁镇某典型铅锌矿区为研究对象,测试了土壤中Pb、Zn、Mn、Cu、Cd、Hg、As的含量,分析其空间分布特征,应用内梅罗综合污染指数法(P_(N))和地累积指数法(I_(geo))开展生态风险评价,并用主成分分析法(PCA)和正定矩阵因子分解法(PMF)对土壤重金属来源进行解析。结果表明,研究区土壤中Pb、Zn、Mn、Cu、Cd、Hg和As的平均含量分别是贵州省土壤重金属元素背景值的0.69、1.51、0.89、0.99、0.21、15.36、0.36倍,其中,Cu平均含量与背景值接近,Zn、Hg平均含量均超过背景值,存在不同程度的富集。Pb、Zn、Mn和Cd在尾矿堆积区含量较高,Cu、Hg和As含量较高的区域分别为尾矿堆积区下游村寨、尾矿堆积区农田和尾矿河流区下游河流分支口。Pb、Zn、Cd、Hg和As为强变异(CV>0.30),空间异质性强,可能受人为来源控制。内梅罗综合污染指数法和地累积指数法评价发现,研究区土壤Hg处于较高生态风险等级,是生态风险的主要贡献因子。相关性分析表明,铅锌矿区土壤存在一定程度的Pb、Zn、Cd复合污染。PCA与PMF源解析显示研究区土壤重金属受矿业污染源、工农业污染源和自然源的共同影响。

Taking a typical lead-zinc mining area in Xingren Town,Danzhai County,Guizhou Province as the research object,the paper tested and analyzed contents of Pb,Zn,Mn,Cu,Cd,Hg,As and their spatial distribution characteristics in the soil.Nemerow comprehensive pollution index method(P_(N))and geo-accumulation index method(I_(geo))were applied to assess the ecological risk,and the source of heavy metals in soil was explored in terms of principal component analysis(PCA)and positive definite matrix factorization(PMF).The results show that the average content of Pb,Zn,Mn,Cu,Cd,Hg and As in soil of the study area was 0.69,1.51,0.89,0.99,0.21,15.36,0.36 times of the background value in the soil of Guizhou Province,respectively.The average content of Cu was close to the background value,but those of Zn and Hg exceed the background value,meanwhile,there was enrichment of the heavy metals in soils at different degrees.The content of Pb,Zn,Mn,and Cd was higher in the tailing accumulation area.While the areas with higher Cu,Hg and As content were the villages in the downstream of the tailing accumulation area,the farmland in the tailing accumulation area,and the branch of the river downstream of the tailing river area,respectively.Pb,Zn,Cd,Hg and As were characterized with strong variability(CV>0.30)and strong spatial heterogeneity,they were possibly controlled by human factors.The evaluation results of Nemerow comprehensive pollution index method and geo-accumulation index method shows that soil Hg in the study area was at a higher ecological risk level,which was the main contributor to ecological risk.Correlation analysis shows that there was a certain extent of Pb,Zn,and Cd compound pollution in the lead-zinc mining area.PCA and PMF source analysis shows that the heavy metals of soil in the study area were affected by mining pollution sources,industrial and agricultural pollution sources,and natural sources.