Root uptakes of $^{54}Mn,;^{60}Co,;^{85}Sr;and;^{137}Cs$ by rice were studied through a greenhouse experiment in which the upper 20 cm of the culture box was filled with an acidic loamy-sandy soil and a mixed solution of the radionuclides was applied to the surface water on the soil 2 days before, and 5 different times after, transplanting. Percent uptakes of the radionuclides to rice tops varied $3.4{sim}13.7%,;0.03{sim}0.1%,;0.6{sim}1.5%,;0.02{sim}0.15%$, respectively, with application time. Among radionuclides, soil-to-plant transfer factors decreased, on the whole, in the order of $^{54}Mn>^{85}Sr>^{60}Co{geq}^{137}Cs$, and among plant parts, in the order of straw > chaff > hulled seed. Transfer factors $(m^2/kg-dry)$ in hulled seed were, depending on application time, $1.2{times}10^3{sim}5.0{{times}10^3;for;^{54}Mn,;1.6{times}10^5{sim}2.6{times}10^4;for;^{60}Co,;1.1{times}10^4{sim}7.6{times}10^4;for;^{85}Sr;and;5.2{times}10^5{sim}7.0{times}10^4;for;^{137}Cs$. The highest factors of all the radionuclides in straw came from the application at 67 days after transplanting while those of $^{54}Mn,;^{60}Co;and;^{85}Sr$ in hulled seed appeared at later applications. The data from this studv can be referred to in assessing the radiological impact of an accidental contamination during the rice growth.
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