小麦-土壤系统中~(95)Zr的消长动态

采用模拟污染物的同位素示踪技术研究了95Zr在小麦-土壤系统中的迁移、消长和分配动态,并建立了其行为规律的数学模型。结果表明:(1)95Zr由表土进入系统后即在系统中发生迁移,小麦主要经根吸收95Zr,然后向其它各部位转移和分配。小麦植株中95Zr比活度起初随时间迅速增高,在达到某一最大值后开始下降。根中95Zr比活度显著高于植株其它部位,小麦各部位中95Zr比活度的大小顺序为:麦根>麦秸>麦壳>麦粒。(2)土壤中95Zr主要滞留于表层6cm内,其比活度与距土表深度呈单项指数负相关。(3)95Zr在小麦-土壤系统中比活度的动态变化规律由多项指数描述。(4)小麦对土壤中的95Zr具有一定的富集能力。95

Dynamics of Accumulation and Disappearance of Zirconium- 95 in Wheat- Soil System

The dynamics of transportation, accumulation, disappearance and distribution of 95Zr in the wheat-soil system is studied by using isotope-tracer techniques for simulated pollutants, and the mathematical model of the behavior law is built. It was shown that (1) 95Zr was transported rapidly in the system after it was put into the surface layer of soil. The uptake of 95Zr by wheat was mainly via root, and redistribution in all parts of wheat occurred consequently. The concentration in root was much higher than that of hers parts of wheat plant. The specific activity of 95Zr in wheat plant rapidly increased to a maximum value, then decreased. The specific activity of 95Zr in each part of wheat plant was found to be arranged in order of root > straw > husk > seed. (2) 95Zr is mainly detained in 6cm of soil surface, and specific activity of 95Zr in soil present an individual exponential declining with depth of soil.(3)The dynamic law can be described as multinomial exponential function of concentration in the wheat-soil system.(4)The wheat plant has some ability to accumulate 95Zr in soil.