Behaviour of radioactive elements in the vegetation of uranium mine

To improve the predictability of radium transfer from soil to plant, the behaviour was compared with other alkaline earth elements. I analyzed the radium transfer ratio as the factor of solubility from soil to water, absorbability by plant from soil, and the allocation to each organ for three grass fields in Ningyo-Toge environmental engineering center. The results indicated that the behaviour of radium is correlated with that of other alkaline earth elements. Moreover negative correlation was found between the absorbability of each element and the concentration of Mg and/or Ca in soluble fraction. From the results, it was suggested that the absorption of radium should be influenced by the regulation of the absorption of these nutrients. Secondly, to clarify the soil- and plant-specific feature of the radium transfer, the radium transfer was investigated for twelve plant species from four vegetation. There was 60 times of difference in radium concentration among plant species. It was observed that there is strong correlation between the transfer factor of radium and that of calcium. The differences in radium concentration of plant were explained by the soil-specific difference in the concentration ratio of radium and the plant-specific difference in calcium concentration. (author)