Transfer and bioaccumulation of 210Po from soil to water spinach (Ipomoea aquatica Forrsk.) in Vietnam

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.

An isotope generator of Po-210 based on SR resin

The work describes an isotope generator of polonium-210 based on an extraction chromatographic resin SR Resin. It was shown that a high selectivity of 4,4'(5')-di-t-butylcyclohexano-18-crown-6, an active component of SR Resin, for lead allows a clear separation of Pb-210 from impurities, easy elution of Po-210 with 5-7 mL of 0.05 M nitric acid solution as well as good retention of Pb-210 in the generator. The content of alpha emitting impurities in the Po-210 eluate did not exceed 0.65%. The experience of 3-years exploitation of the generator is described. It was shown that the SR Resin was stable against irradiation and complete drying, and Pb-210 loss from the SR Resin column for 3 years (seven elutions) was near to loss due to its radioactive decay within the error limits (less than 7%).

Study of Polonium (210Po) Activity Concentration in Fruit Wines Derived from Different Locations in Poland

This study aimed at assessing the activity concentration and the annual effective dose of polonium-210 (210Po) in fruit wines derived from four locations in Poland (Warmian−Masurian, Podlaskie, Lubelskie and Małopolskie voivodeships). The fruit wines differed significantly (p < 0.05) in 210Po activity depending on the production site, with the Małopolskie site having the highest activity (61.4−221.4 mBq/L) and the Podlaskie having the lowest (3.5−97.1 mBq/L). The site differentiation was due to environmental conditions—soil parameters (uranium concentration), precipitations and terrain characteristics, e.g., the proximity of the lakes. The increased activity concentration of 210Po in samples from Małopolska compared with the other sites probably derived from the environment polluted with aqueous wastes and particulate air pollution. The annual effective dose due to the ingestion of fruit wines ranged from 0.112 to 1.214 µSv/year. These levels of exposure are safe according to the WHO criterion (0.1 mSv per year for ingestion) and to the IAEA reference level for public exposure including food (1 mSv per year). Summing up, the data obtained provide information on the activity concentration of 210Po in fruit wines and increase databases on the natural radioactivity of foodstuffs. Future work is needed to examine 210Po activity in samples from all vineyard regions in Poland.