Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) under flooded and unflooded conditions in Hanoi, Vietnam

Transfer of natural radionuclides from soil to water spinach (Ipomoea aquatica Forssk) in Hanoi, Vietnam have been investigated using a low background gamma spectrometer with an HPGe detector (Model-GC5019). Twenty pairs of soil and water spinach samples in two environmental conditions, i.e., flooded and unflooded, were collected for measuring the activity concentrations and determining the soil-to-plant transfer factors (TFs) of natural radionuclides. For water spinach, stems and leaves were collected as the main parts for human consumption and livestock food. The TF of 40K is within the range of 0.32–2.49, which is greater than that of 228Ra (0.01–0.17) and 226Ra (0.01–0.13). The geometric means (geometric standard deviations) of the TFs are 1.17(1.89), 0.05(2.41) and 0.04(1.88) for flooded sites, and 0.89(1.73), 0.03(2.12) and 0.03(1.82) for unflooded sites, respectively. Comparing between the flooded and unflooded sites, the TFs are all greater at the flooded sites. •The TFs of natural radionuclides in water spinach in Hanoi, Vietnam were investigated.•Two environmental conditions were examined: flooded and unflooded.•The TFs in flooded sites are all greater than that in unflooded sites.