Relationship between magnetization and trace elements content of Brazilian soils from different parent materials
Relationship between magnetization and trace elements content of Brazilian soils from different parent materials
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DOI：
10.1097/00010694-200010000-00007
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发表时间：
2000-10
期刊：
影响因子：
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通讯作者：
T. S. Oliveira;M. Fontes;L. M. D. Costa;A. Horn
中科院分区：
文献类型：
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作者：
T. S. Oliveira;M. Fontes;L. M. D. Costa;A. Horn
磁性矿物在某些巴西土壤中很重要，它们是微量元素的可能来源，特别是在高度风化的土壤中。因此，本调查的目的是确定微量元素含量的磁性分离的砂，粉土，粘土部分从不同的岩性来源的土壤，以测试的假设，即较高水平的磁化强度是成正比的这些元素的含量。采用浓HCl/HF/HClO 4酸蚀法溶解样品，用电感耦合等离子体原子发射光谱法（ICP-AES）测定Cd、Cr、Cu、Ni、Pb、Zn、Zr和V的含量。微量元素的含量在总，磁性和磁性砂，粉砂，粘粒级的正常范围内提出的整个土壤中的镉，这是较高的。用一种特殊的分析天平对总的、磁性的和非磁性的土壤组分的磁化强度（σ s）进行了评估。砂的σ s值较高，粉砂和粘土组分的σ s值较低。磁浓缩级分给出的结果以相同的方式变化，但达到更高的值。通过相关性分析研究了土壤组分中微量元素与磁化强度之间的关系，当来自于itabirite的土壤被排除在分析之外时，得到了更高和更显著的相关系数。由于铁白云石和镁铁质岩具有较高的磁化强度，相关结果表明，镁铁质岩发育的土壤磁化强度与微量元素含量之间存在显著的相关性。方差分析表明，镁铁质岩发育的土壤中，磁性组分与非磁性组分的微量元素含量存在显著差异，尤其是砂和粉砂组分。Tukey的平均值比较试验表明，与其他母质相比，镁铁质岩具有较高的微量元素含量。所获得的结果证实了微量元素的地球化学亲和力和来自镁铁质岩石的土壤的磁性部分的组成部分，主要是砂和粉砂部分，其中较高的含量的调查微量元素进行了观察。
Magnetic minerals are important in some Brazilian soils and they are a possible source of trace elements, especially in the highly weathered soils. The purpose of this investigation was thus to determine the trace element content in the magnetically separated sand, silt, and clay fractions from soils of different lithological origins in order to test the hypothesis that higher levels of magnetization are directly proportional to the contents of these elements. To accomplish this objective, the samples were dissolved by concentrated HCl/HF/HClO 4 acid attack, and the contents of Cd, Cr, Cu, Ni, Pb, Zn, Zr, and V were analyzed by atomic emission spectroscopy with inductively coupled plasma (ICP-AES). The contents of trace elements in the total, magnetic and nonmagnetic sand, silt, and clay fractions were within the normal range presented by whole soils with the exception of Cd, which was higher. Magnetization (σ s ) of the total, magnetic and nonmagnetic soil fractions was evaluated with a special analytical balance. The σ s values were higher for sand and lower for silt and clay fractions. The magnetically concentrated fractions gave results with variation in the same fashion but reaching higher values. The relationship between trace elements in soil fractions and magnetization, studied by correlation analysis, gave higher and more significant correlation coefficients when a soil derived from itabirite was excluded from the analysis. Because itabirite and mafic rocks have high magnetization, the correlation result demonstrates that there is a strongly significant association between magnetization and trace element contents for the soils derived from mafic rocks. Analysis of variance showed that there were significant differences between trace element contents of the magnetic compared with the nonmagnetic fractions of the soils derived from mafic rocks, especially in their sand and silt fractions. Tukey's test for comparison of means showed that mafic rocks have a higher content of trace elements compared with the other parent materials. The results obtained confirm the geochemical affinity of trace elements and the components of the magnetic fraction of the soils derived from the mafic rocks, mainly for sand and silt fractions, where higher contents of the investigated trace elements were observed.