【摘要】 环境磁学方法针对城市、矿区、工业区等特定区域土壤的研究现已比较普遍,但在农业土壤重金属研究中的应用还比较少。本文对采自佛山市的532件农业表层土壤样品进行低频(976 Hz)和高频(15 616 Hz)磁化率测试,在分析其空间分布特征的基础上选取175件(其中,旱地土样149件,水田土样26件)代表性样品进行重金属(Cd、Pb、Cr、Cu、Ni、Zn、Hg、As)含量的分析测试。在分析不同土壤样品磁化率与重金属含量之间相关关系的基础上,从旱地和水田土壤中分别挑选出6种与低频磁化率高度相关的重金属元素(旱地Ni、Cu、Cr、Zn、Cd、Pb,相关系数分别为0.599、0.492、0.279、0.510、0.445、0.225;水田Ni、Cu、Cr、Zn、Cd、Hg,相关系数分别为0.728、0.699、0.606、0.602、0.764、0.450)进行回归分析,列出回归方程,并得到一些初步认识。主要有(1)低频磁化率与频率磁化率在空间分布上总体呈现相反趋势;(2)重金属含量与低频磁化率总体呈正相关,但正相关的元素种类在旱地和水田土壤中有所差异;(3)所研究的旱地土壤重金属含量与频率磁化率呈负相关关系,但这种相关关系在水田土壤中没有明显表现;(4)Pb元素在旱地土壤中与低频磁化率表现出显著正相关(P<0.01),在水田土壤中却与低频磁化率和频率磁化率表现出一定的负相关性。(5)通过测定农业土壤的磁化率即可初步推算出相应的重金属含量,为磁学方法在农业表层土壤重金属快速监测领域的进一步应用提供了数据支持和科学依据。更多还原

【Abstract】 Environmental magnetism method has been widely applied in the study of soils from some particular areas such as city, mining and industrial zones. However, few studies focused on its application in heavy metal study for agricultural soil. In the present study, five hundred and thirty-two agricultural topsoil samples collected from Foshan city were selected for magnetic susceptibility measurements under both low(976 Hz) and high(15 616 Hz) frequency. Based on the analysis of spatial distribution of magnetic susceptibility, one hundred and seventy-five representative samples(149 from dry land soil and 26 from paddy soil) were selected for heavy metal(Cd, Pb, Cr, Cu, Ni, Zn, Hg, As) content determination. On the basis of correlationship analysis between magnetic susceptibility and heavy metal concentration, regression analysis was performed for six heavy metal elements(Ni, Cu, Cr, Zn, Cd, Pb for dry land soil, the correlation coefficient with magnetic susceptibility are 0.599, 0.492, 0.279, 0.510, 0.445, 0.225, respectively; Ni, Cu, Cr, Zn, Cd, Hg for paddy soil, the correlation coefficient with magnetic susceptibility are 0.728,.699, 0.606, 0.602, 0.764, 0.450, respectively.), that are significantly correlated with low frequency magnetic susceptibility. The regression equations between low frequency magnetic susceptibility and heavy metal concentration were acquired in this paper. The following preliminary understanding were obtained:(1) A negative trend was appeared between the spatial distributions of low frequency magnetic susceptibility and frequency dependent magnetic susceptibility;(2) Heavy metal concentrations were generally positively correlated with the low frequency magnetic susceptibility. However, the positive correlated heavy metal elements of dry land soil differed from those of paddy soil.(3) A negative correlationship was appeared between heavy metal concentration and frequency dependent magnetic susceptibility for dry land soil. But this correlation was not obvious for paddy soil.(4) The Pb concentration was positively correlated with the low frequency magnetic susceptibility(P<0.01) for dry land soil. However, a certain negtive correlation was appeared between the Pb concentration and the low frequency and also frequency dependent magnetic susceptibility for paddy soil.(5)Heavy metal concentration of agricultural soil can be predicted by it magnetic susceptibility. Data support and scientific basis were provided for the further application of environmental magnetism method rapid monitoring of heavy metals within agricultural topsoil.更多还原