西北干旱区农田土壤磁性特征及其环境意义  

Magnetic Properties of Farmland Soils in Arid Regions in Northwest China and Their Environmental Implications

作　　者：王新[1] 夏敦胜[1] 王博[2] 陈红[1] 刘浩[1] 

机构地区：[1]兰州大学资源环境学院西部环境教育部重点实验室,兰州730000 [2]中国科学院西北生态环境资源研究院,兰州730000

出　　处：《环境科学》2017年第8期3507-3518,共12页Environmental Science

基　　金：国家自然科学基金项目(41071125);中央高校基本科研业务费专项(lzujbky-2013-m03)

摘　　要：为探究环境磁学方法在西北干旱区农田土壤污染监测中的可行性,以典型绿洲农业区张掖市(临泽县、甘州区、民乐县和山丹县)为研究区域,采集农田土壤样品102份并对其进行系统的环境磁学分析.结果表明,张掖市农田土壤磁性特征以亚铁磁性的磁铁矿为主导,磁晶颗粒主要为粗粒假单畴(PSD)和多畴(MD),颗粒等效粒径介于0.2~1μm之间;样品磁化率(χlf)变化范围为22.27×10^(-8)~188.36×10^(-8)m^3·kg^(-1),平均值为63.85×10^(-8)m^3·kg^(-1),磁性矿物含量总体较少但空间变化较大;磁参数空间分布表明,磁性矿物含量在甘州区、民乐县和山丹县高于临泽县,并在甘州区的中部、民乐县的西南边和山丹县的西边呈现相对高值;甘州区中部的磁性高值主要受控于工业生产等人类活动,民乐县西南边和山丹县西边的磁性高值主要与较强的自然成土作用有关.综合多种磁学参数的系统分析能够有效区分和划定农田土壤人为污染范围,为农田土壤污染防治工作提供依据.In order to understand the feasibility of environmental magnetism methods in farmland soil pollution monitoring in the northwest arid areas of China,the environmental magnetic properties of 102 farmland soil samples from four typical agricultural regions,namely Linze county,Ganzhou district,Minle county,and Shandan county in Zhangye City were systematically analyzed. The results show that the main magnetic mineral of farmland soil samples is ferrimagnetic magnetite,and the main magnetic grain sizes are coarsegrained pseudo single domain（ PSD） and multidomain（ MD）,mainly between 0. 2-1 μm in equivalent diameter. The low frequency magnetic susceptibility（ χlf） value of farmland soil samples ranged from 22. 27 ×10^（-8）m^3·kg^（-1）to 188. 36 ×10^（-8）m^3·kg^（-1）,with the average value of 63. 85 ×10^（-8）m^3·kg^（-1）. Overall,the magnetic mineral content of farmland soil samples was low,but it had large spatial variation. The spatial distribution of the magnetic parameters show that the magnetic mineral contents in Ganzhou district,Minle county,and Shandan county are higher than in Linze county,and three relatively high-value areas are present in central Ganzhou district,the southwest side of Minle county,and the west side of Shandan county. High magnetic value in central Ganzhou district is mainly controlled by human activities,such as industrial production,whereas the high magnetic values in the southwest side of Minle county and west side of Shandan county are more related to strong natural pedogenesis. Therefore,systematic comprehensive analysis of magnetic parameters can effectively distinguish and delimit the man-made pollution range in farmland soil and provide a basis for farmland soil pollution prevention and control.

关 键 词：农田土壤 环境磁学 污染监测 磁性特征 张掖市 

分 类 号：X123[环境科学与工程—环境科学] X833