放射性核素^(95)Zr在蚕豆-土壤系统中的迁移动力学

Transference kinetics of radioactive nuclide zirconium-95 in broadbean-soil system

采用模拟污染物的同位素示踪技术研究了95Zr在蚕豆-土壤系统中的迁移、消长和分配动态,并应用库室模型和非线性回归方法确定了各体系的拟合方程.结果表明:195Zr由表土进入系统后即在系统中发生迁移,蚕豆主要经根吸收95Zr,然后向其各部位转移和分配.蚕豆植株中95Zr浓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的浓度显著高于植株其它部位,蚕豆各部位中95Zr的浓度的大小顺序为:根>豆秸>豆壳>豆粒.2土壤中95Zr主要滞留于表层6cm内,其浓度与距土表深度呈单项指数负相关.395Zr在蚕豆-土壤系统中浓度的动态变化规律由多项指数描述.4蚕豆对土壤中的95Zr具有一定的富集能力.

The dynamics of transportation, accumulation, disappearance and distribution of 95Zr in the broadbean soil system was studied by isotopetracer technique, and the fitting equation was established by application of the closed twocompartment model and nonlinear regression method. The results showed: ①95Zr was transported in the system shortly after its addition into the surface layer of soil. 95Zr was absorbed mainly via root of broadbean and then redistributed among all parts of the broadbean plant. The concentration of 95Zr in the whole plant reached a maximum value, which was followed by a steady decrease. The concentration of 95Zr in root was much higher than in other parts of the plant. The concentrations of 95Zr in different parts of broadbean plant arranged in order was root > straw > husk > seed. ②Most of 95Zr detained in 6cm upon layer of the soil, and its concentration was single term exponential negative relation with depth of soil. ③The dynamics of 95Zr in broadbeansoil system could be described using multinomial exponential. ④Broadbean plant has the ability of enriching with 95Zr from soil to some extend.