万盛采矿区土壤As,Cd,Zn重金属含量光谱测量与分析

Estimation of Soil's Heavy Metal Concentrations(As,Cd and Zn) in Wansheng Mining Area with Geochemistry and Field Spectroscopy

随着现代工业技术的飞速发展以及人类活动的影响，土壤中重金属污染问题愈发严重，土壤重金属污染已经成为当前全球面临的很严峻的环境问题，也逐渐成为了全球土壤和环境研究的重点。传统的通过点样测量的方法获取土壤重金属含量虽然精度较高，但是耗时耗力，成本较高，且不能大面积、快速得到所研究区域的重金属含量分布。遥感技术的发展为土壤重金属含量的研究提供了新的思路，为了使用遥感技术反演某地区土壤重金属含量，了解其光谱特征是快速、准确建立反演算法的基础。以重庆市万盛采矿区为研究区，分别在2012年3月和8月用ASD FieldSpec Pro Ⅲ地物光谱仪（350-2500nm）对该地区171组和123组土壤样进行了现场光谱测定，并在第二次光谱采集的时候对其中的40个土壤样进行了土壤化学分析以建立土壤中一种莺金属含量的反演模型，为遥感定量反演研究区土壤As，Cd，Zn三种重金属含量提供科学依据。结果表明：在万盛采矿区，土壤在近红外波段R2320与R1755波段、R2260与R2210、R1920与可见光波段R480波段的反射值比值分别和土壤中As，Cd和Zn含量存在较好的相关性，由此可根据采样点光谱及地理插值获得研究区土壤中As，Cd和Zn含量的分布图。

In the present paper, Chongqing Wansheng mining area was selected as the study area, and the ASD FieldSpec Pro I]1 portable spectroradiometer （350 to 2 500 nm） was used as the spectral measurement instrument to collect the reflectance spectra of 171 soil samples and 123 soil samples in March and in August 2012 respectively. In order to create the retrieval model to re- trieve soil heavy metal concentration, 40 among the 123 soil samples in august 2012 were collected to do chemical analysis. Then, the heavy metals＇ concentration and the reflectance of the 40 soil samples were analyzed together. The results show that the ratio of the reflectance at 2 320 and 1 755 nm in the nearinfrared range, the ratio of the reflectance on 2 260 and 2 210 nm in the nearinfrared range, and the ratio of the reflectance at 480 and 1 920 nm in the visible and near infrared range has a significant correlation with heavy metal concentration of As, Cd and Zn respectively, so the spectral absorption feature parameters（SAFP） for retrieving soil heavy metal concentration of As, Cd and Zn from soil reflectance was created. Thus, the soil heavy metal con- centration of As, Cd and Zn of the soil samples can be retrieved with the reflectance spectra. Then the distributions of the soil heavy metal concentration of As, Cd and Zn were obtained with the interpolation method in study area in March and in August 2012 respectively.