Transfer factors of 90Sr and 137Cs from soil to the sweet potato collected in Taiwan

The activity concentrations of 90Sr and 137Cs in sweet potatoes collected at eight locations in Taiwan were measured using radiochemical analysis and γ-ray spectrometry. 90Sr is found to be more concentrated in leaves than in storage roots (the mean activity ratio of storage roots to leaves is 0.55), while 137Cs distributes homogeneously in both storage roots and leaves (the corresponding ratio for 137Cs is 0.94). The mean transfer factors of 90Sr and 137Cs from soil-to-storage roots are determined to be 0.55 and 0.095, respectively, while the mean transfer factors of 90Sr and 137Cs from soil to leaves are 1.38 and 0.105, respectively. The effective dose equivalent values due to the dietary intake of 90Sr and 137Cs through sweet potato for the Taiwanese are estimated to be 9.38×10-8 and 2.37×10-8 Sv yr-1, respectively