~(60)Co在小麦-土壤系统中的消长动态

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。

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

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.