^60 Co在小麦-土壤系统中的消长动态

DYNAMICS OF ACCUMULATION AND DISAPPEARANCE OF COBALT-60 IN WHEAT-SOIL SYSTEM

采用模拟污染物的核素示踪技术研究了60Co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)60Co由表土进入系统后即在系统中发生迁移,小麦主要经根部吸收60Co,然后向其他各部位转移和分配。小麦植株中60Co比活度起初随时间迅速增高,达到某一最大值后开始下降。根中60Co比活度显著高于植株其他部位,小麦各部位中60Co比活度的大小顺序为:麦根>麦秸>麦壳>麦粒;(2)土壤中60Co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)60Co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60Co具有一定的富集能力。

The dynamics of transportation, accumulation, disappearance and distribution of ^60 Co in the wheat-soil system was studied by using isotope-tracer techniques for simulated pollutants, and the mathematical model of the behavior was established. Rescilts showed that （ 1 ） ^60 Co was transported rapidly in the system after the application on soil surface layer. The uptake of ^60 Co by wheat was mainly via root, and redistribution in all parts of wheat occurred consequently. The concentration in root was much higher than that in other parts of wheat plant. The specific activity of ^60 Co in wheat plant rapidly increased to a maximum value, then decreased. The specific activity of ^60 Co in each part of wheat plant was found in the order of root 〉 straw 〉 husk 〉 seed. （2） ^60 Co is mainly detained with in 6cm of soil surface, and specific activity of ^60 Co in soil present a simple 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 certain ability to accumulate ^60 Co from soil.