河北省典型铅锌矿区重金属来源解析及生态风险评价

Heavy metal sources and ecological risk assessment of typical lead-zinc mining areas in Hebei Province

为揭示河北省典型铅锌矿区重金属来源及生态风险,以河北省某铅锌矿区周边区域为研究对象,通过系统的田间采样采集了156件土壤样品,通过主成分分析(PCA)及正定矩阵因子分解(PMF)模型分析,分析了区域内重金属的来源;运用地累积指数法及潜在生态风险指数法进行了风险评价。研究结果表明,Cr,Ni,Cu,Zn,As,Cd,Pb和Hg质量分数平均值分别为53.6,25.7,62.7,692,10.6,1.75,142,0.129 mg/kg,除Cr,Ni和As外,其余5种重金属均处于不同的污染水平,平均值均超河北省土壤背景值,Hg,Cd,Zn,Pb和Cu的变异系数均大于1.75,As的变异系数大于0.5,表明这6种重金属属于高度变异。源解析显示,研究区土壤重金属的主要来源为采矿活动、自然来源、农业活动和金矿冶炼,其中,Pb,Zn和Cd主要源于采矿活动;Cr,Ni主要受自然母质的影响,属于自然来源;Cu主要受农业活动和采矿活动的双重影响;As受自然来源、采矿活动和农业活动三重控制;Hg主要源于金矿冶炼和采矿活动。PCA与PMF模型有机结合、彼此印证,增加了重金属来源解析结果的可信度。研究区存在人为因素引起的Hg和Cd污染,地累积指数和潜在生态风险指数高,生态风险总体属于极高生态风险,需要重点关注并开展治理工作。

[Objective] To reveal the sources and ecological risks of heavy metals in a typical lead-zinc mining area in Hebei Province,156 soil samples were collected around a zinc mining area in Hebei Province through a systematic field sampling method.[Methods] The sources of heavy metals in the area were analysed via principal component analysis(PCA) and a positive matrix factorization(PMF) model.The risk assessment was carried out according to the index of geoaccumulation method and potential ecological risk index method.[Results] The results show that the mean values of Cr,Ni,Cu,Zn,As,Cd,Pb and Hg are 53.6,25.7,62.7,692,10.6,1.75,142,0.129 mg/kg,respectively.Except for Cr,Ni and As,the other 5 elements present at different pollution levels.Above the background values of the soils in Hebei Province,the coefficient of variation of Hg,Cd,Zn,Pb and Cu is more than 1.75,and the coefficient of variation of As exceeds 0.5,indicating the high variability of these 6 elements.The results of the source analysis reveal that the main sources of soil heavy metals include mining activities,natural sources,agricultural activities,and gold smelting.Zn,Cd and Pb were mainly derived from mining activities;Cr and Ni were influenced by natural parent materials and were derived from natural sources;Cu was mainly derived from agricultural activities and mining activities;As was controlled by natural sources,mining activities and agricultural activities;and Hg was originated from mainly gold smelting and mining activities.The combination of PCA and the PMF model to corroborate each other facilitates the reliability of the heavy metal source analysis results.[Conclusion] There is anthropogenic Hg and Cd contamination in this area,as indicated by the high geoaccumulation indices and potential ecological risk indices.In addition,the ecological risk in general was found to be very high,and attention needs to be given to and management work to be carried out.