广西某铅锌尾矿库区土壤中重金属Cd、Pb、Zn、Cu的分布特征及源解析

针对广西某铅锌尾矿库区周边土壤中重金属Cd、Pb、Zn、Cu的含量、分布特征及其污染源，采用地统计学分析法和正定矩阵因子分解法进行了探究。含量测定结果表明，尾矿库区土壤中4种金属含量平均值分别为19.49(Cd)、465.65(Pb)、206.58(Zn)和36.64(Cu) mg/kg，分别是广西土壤背景值的73.0(Cd)、19.4(Pb)、2.7(Zn)和1.3(Cu)倍；以农用地土壤标准计，超标率分别为100%(Cd)、43.5%(Pb)、43.5%(Zn)和26.1%(Cu)，其平均含量为农用地土壤污染风险筛选值的65.0(Cd)、5.17(Pb)、1.03(Zn)和0.73(Cu)倍。重金属空间分布结果表明，Cd在尾矿库东面和南面区域含量达到20~80 mg/kg，西北方向在一定范围内由近及远呈梯级分布；Pb和Zn主要分布在东部和西部，Cu则主要分布在东面。源解析结果表明，该尾矿库区土壤中4种重金属的来源主要包括：铅锌工业活动源、交通运输源和土壤母质源，各污染源的平均贡献率分别为46.34%、28.02%、25.64%。铅锌工业活动和交通运输是尾矿库区土壤重金属污染的主要来源，是污染防治措施制定和实施的主要对象。

Soil pollutant distribution and source analysis for Cd, Pb, Zn and Cu in a lead-zinc tailings area of Guangxi

In this paper, the content, distribution and pollution sources of Cd, Pb, Zn and Cu in soil around a lead-zinc tailings area in Guangxi were investigated by geostatistical analysis and positive definite matrix factorization. The heavy metal content in soil were19.49 (Cd), 465.65 (Pb), 206.58 (Zn) and 36.64 (Cu) mg·kg-1, which were 73.0 (Cd), 19.4 (Pb), 2.7 (Zn) and 1.3 (Cu) times of the soil background value in Guangxi. According to the soil standard of agriculture, the excess rates were 100% (Cd), 43.5% (Pb), 43.5% (Zn)and 26.1% (Cu), which were 65.0 (Cd), 5.17 (Pb), 1.03 (Zn) and 0.73 (Cu) times of the standard values. The distribution of Cd was found spreading in the east and south of the tailings area with the content varied in the range of 20-80 mg·kg-1. and in the northwest direction, it was distributed in steps from near to far within a certain range. Pb and Zn were mainly distributed in the east and west sides, while Cu was in the east side. The pollution contribution analysis revealed that lead and zinc industrial activities (46.34%), mineral transportation (28.02%) and self-content of parent soil (25.64%) were the major sources of heavy metal pollution. The results suggested a way for the formulation and implementation toward heavy metal pollution control.