基于地面实测光谱的水系沉积物重金属含量反演

Study on Inversion of Soil Heavy Metal Elements Concentrations in Stream Sediments by In-Situ Hyperspectral Measurements

水系沉积物中的重金属元素含量调查是矿区环境受污染程度的重要依据，同时水系沉积物的物源组成也是近年来找矿突破的重要环节之一。通过分析水系沉积物中羟基官能团与重金属游离态阳离子之间的吸附反应，结合地面实测高光谱数据，发现与重金属元素含量相关性较好的波谱波段为500～780 nm 与2100～2300 nm，建立基于地面实测光谱技术反演水系沉积物中重金属元素含量的回归方程，最后利用反距离权重方法成功提取碾子沟-洛金洼多金属矿区3条冲沟水系沉积物中 Cu、Zn 等重金属元素含量。结果显示：重金属 Cu 和 Zn 模型检验精度（R 2）分别为0．618和0．636；研究区内冲沟源头山地林地附近流域沉积物中的重金属含量相对中下游矿区周边农用地较低，同时沉积土壤中的重金属含量随着冲沟流向呈升高趋势。重金属含量较高的中游农用地附近应加以治理，含量异常的中下游区域为今后的找矿方向。

The heavy metal elements contents in stream sediments provide the evidences for evaluating the soil-contaminated degree in the mining area.And they are also used to predict the potential of the mines.Based on adsorption mechanism of hydroxyl groups in the stream sediments and free positive ions,in-situ hyperspectral measurements are analyzed to make sure that the best relevance between the soil spectral variables and soil heavy elements concentrates is on the wavelength of 500 780 nm and 2 100 2 300 nm.Thus the regression equations for the field spectral features and metal element concentrations are determined to estimate the heavy metal element contents.The inverse distance weighting method is employed to retrieve the heavy metal contents,Cu and Zn,in stream sediments successfully.And the R 2 of Cu is 0.618 and the R 2 of Zn is 0.636.The results show that the heavy metal elements contents in the mountain and forest regions are lower than what in the middle reaches of the streams and the content has a rising trend along the river flowing direction.Furthermore,there exists a high-value anomaly zone in the middle and lower reaches,which provides the evidence for future investigation.