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研究论文

白占国,万曦,万国江,王长生,黄荣贵.岩溶山区表土中⁷Be、¹³⁷Cs、²²⁶Ra和²²⁸Ra的地球化学相分配及其侵蚀示踪意义[J].环境科学学报,1997,17(4):407-411

GEOCHEMICAL SPECIATION OF ⁷Be, ¹³⁷Cs, ²²⁶Cs and ²²⁸Cs IN SOILS OF THE KARST REGION, SOUTHWESTERN CHINA AND THEIR EROSION TRACE

摘要：岩溶山区表土中⁷Be、¹³⁷Cs、²²⁶Ra和²²⁸Ra地球化学相分配的实验研究表明,4种核素绝大部分(85%以上)存在于Fe Mn氧化物、有机质及残渣相中。它们在表土的迁移过程中具微粒迁移性,能较好地随土粒般运,可作为土粒侵蚀或沉积的示踪剂。但其微粒示踪类型又各具特征：⁷Be的化学形态与其季节性微粒迁移示踪一致；¹³⁷Cs的化学形态适用于示踪土粒累计性迁移和沉积计年；²²⁶Ra和²²⁸Ra存在于粘土矿物结晶骨架中,在表土中主要以残渣相存在,由矿物化学风化作用而转入可溶解、可交换及碳酸盐结合相的比例很小,二者比活度的形态变化分异具有很好的侵蚀堆积示踪价值。

Abstract：The experimental results of geochemical speciation in the soils show that more than 85% of ⁷Be, ¹³⁷Cs, ²²⁶Cs and ²²⁸Cs are bound to organic matter, Fe Mn oxy hydroxide and residual fractions. They can be moved with soil particles and used as tracers for erosion and/or accumulation of soil particles. ⁷Be geochemical speciation in the soils agrees with its trace for seasonal particle transport. ¹³⁷Cs geochemical speciation is suitable to trace soil particle accumulation as well as sediment dating. ²²⁶Cs and ²²⁸Cs are combined in crystalline skeleton of clay minerals and mainly remain as a residue in the soils and very little is bound to the soluble, exchangeable, carbonate fractions. The differentials of ²²⁶Cs/ ²²⁸Cs activity ratios in different geochemical speciation in the soils can be used as a parameter to trace accumulation and/or erosion of soil particles.