滇西兰坪金顶超大型铅锌多金属矿床是我国最重要的铅锌矿产集中开发区之一。始于20世纪80年代的矿业开发活动逐渐增强,导致该区土壤重金属污染问题不断加重。本文系统开展了兰坪矿区土壤样本的Zn、Pb、As、Cd共4种重金属含量与光谱响应测试实验,详细分析了土壤样本中4种重金属的敏感波段位置及其与土壤中粘土矿物、铁氧化物及碳酸盐矿物之间的赋存关系,构建了4种重金属含量与土壤实测光谱之间的多元线性回归模型。结果表明:(1)区内4种重金属元素含量均超标,且具显著的相关性;(2)重金属含量与土壤光谱反射率、反射率的一阶微分及连续统去除变量具有较高的相关性;(3)用实测光谱的逐步回归方法预测土壤重金属含量的反演模型具有较高的精度,R2均高于0.816。本结果可为大尺度土壤重金属含量监测及其它污染信息提取提供借鉴。
The Jinding giant Zn-Pb polymetallic deposit, located in Lanping County, western Yunnan Province is one of the most important mining areas of lead and zinc resource in China. The continuous active mining has induced increasing heavy soil pollution in and around this area since the 1980 s, and is an ideal region to analyze the mining environmental problems. Based on the field work and sample collection, the authors measured the content of four heavy metals of zinc, lead, arsenic, cadmium in 77 soil samples and analyzed the sensitive bands of these heavy metals and their occurrences within soil clay minerals, iron-manganese oxides and carbonates. On such a basis, the Multiple Linear Regression Models( MVLR) was constructed between these four kinds of heavy metals and their measured spectra of the soil. Some results have been obtained:(1) the values of the four kinds of heavy metals in this area all exceed the standard values, and show significant correlations;(2)the values of these heavy metals have a high correlation with the soil spectral reflectance, the first-order differential equation of the reflectance and the continuum removed variables;(3) the accuracies( R^2) of the fitting models are higher than 0. 816, which proves that the predicting heavy metal content based on the measured spectra is feasibleand reliable. So, the results can provide a technical support for retrieving the heavy metal content of soil by hyperspectral remote sensing technology and for mapping soil heavy metal pollution on large scale by satellite or aerial remote sensing technology.