@article{oai:repo.qst.go.jp:00075834,
 author = {Tagami, Keiko and Uchida, Shigeo and Tagami, Keiko and Uchida, Shigeo},
 journal = {Soil-to-Crop Transfer Factor of Uranium: Consideration on Excess U from Phosphorus Fertilizer. In: Uranium in Plants and the Environment},
 month = {May},
 note = {In this chapter, we used the initial U/Th concentration ratio in non-agricultural soil s to estimate the concentrations of excess U (essU) in agricultural fields in Japan due to long-term application of phosphorus fertilizers as a means to understand the bioavailability of added U to soil. We carried out a data survey and obtained U/Th ratios from 210 non-agricultural soil samples collected throughout Japan; the values distributed log-normally and they ranged from 0.006 to 0.9 with the geometric mean value of 0.26. Because concentrations of Th are lower in phosphorus fertilizers than those of U, we assumed that Th concentrations in agricultural soils kept their initial values. Thus, the geometric mean U/Th value and Th concentrations in agricultural soils were used first to calculate the initial U concentration in soil, and then, by subtracting the value from total U in the soil, the essU concentrations in the soil were estimated. Uranium in phosphorus fertilizer was thought to be soluble so we hypothesized that essU would be easily taken up by crops; however, there were no correlations between brown rice and essU nor for potato and essU. These results suggested that the added U was fixed to the soil particles so that essU would not be easily taken up by crops. We also found that there was no significant difference between soil-to-plant transfer factors obtained in low and high essU soil conditions for brown rice and potato; this means that the essU and the initial U in soil-to-crop systems had the same fate. Thus, soil-to-crop transfer factors obtained using U in agricultural fields should be valid in long-term radiation dose assessment models.},
 title = {Soil-to-Crop Transfer Factor of Uranium: Consideration on Excess U from Phosphorus Fertilizer. In: Uranium in Plants and the Environment},
 year = {2019}
}