Main Article Content
This paper studies the soil-to-plant transfer factors of natural occurring radioisotopes (238U and 232Th) on Luong My Tea farm, Tan Thanh district, Luong Son commune, Hoa Binh province. The activity concentrations in leaves, trunk and roots of the tea tree at no harvest period (winter break) were determined. The measurements were carried out using gamma spectroscopy with high puritygermanium detector HP(Ge). The research results show that the activity of 238U and 232Th is higher in the tea tree’s leaves than in its trunk and roots. The soil-leave transfer factors (TF) for 238U and 232Th were determined as follows: TFU-238 = 0.52 – 0.87; TFTh-232 = 0.25 – 0.43.
 A. TermiziRamli, A.Wahab, M.A. Hussein, A.Khalik Wood, Environmental 238U and 232Th concentration measurements in an area of high level natural background radiation at Palong, Johor, Malaysia.J. Environ. Radioact. 80 (2005) 287–304.
 F. Vera Tome, P.B. Rodrigues, J.C. Lozano, Distribution and mobilization of U, Th and 226Ra in the plant–soil compartments of a mineralized uranium area in South-west Spain. J. Environ. Radioact. 59 (2002) 223–243.
 C. Galindo, L. Mougin,S.Fakhi, A. Nourreddine, A. Lamghari, H. Hannache, Distribution ofnaturally occurring radionuclides (U, Th) in Timahdit black shale(Morocco). J. Environ. Radioact. 92 (2007) 41–54.
 E. Mazor, Uranium in plants of Southern Sinai.J. Arid Environ. 22 (1992) 363–368.
 J.J. Mortvedt, Plant and soil relationships of uranium and thorium decay series radionuclides – a review. J. Environ. Qual. 23, (1994) 643–650.
 S.C. Sheppard, W.G. Evenden, The assumption of linearity in soil and plant concentration ratios: an experimental evaluation. J. Environ. Radioact. 7 (1988) 221–247.
 Y. Thiry, P. Schmidt, M. Van Hees, J. Wannijn, P. Van Bree, G. Rufyikiri, H. Vandenhove, Uranium distribution and cycling in Scots pine (PinussylvestrisL.) growing on a revegetated U-mining heap. J. Environ. Radioact. 81, (2005) 201–219.
 T. Tsuruta, Bioaccumulation of uranium and thorium from the solution containing both elements using various microorganisms. J. Alloys Compd. 408–412 (2006) 1312–1315.
 M.P. Vera Tome, J.C. Blanco Rodrı ´guez, Lozano, Soil-to-plant transfer factors for natural radionuclides and stable elements in a Mediterranean area, Journal of Environmental Radioactivity 65 (2003) 161–175.
 Shtangeeva, Uptake of uranium and thorium by native and cultivated plants, Journal of Environmental radioactivity 101 (2010) 458-463, Russia.
 L.T. Anh, P.V. Cuong, N.C. Tam, N.H. Ha, H.T. Thao, H.H. Duc, S. Leuangtakoun, L.Q. Viet, B.V. Loat, A development for determining the activity of radionuclides in the environmental sample by HPGe γ-spectroscopy using only one absolute efficiency value and an intrinsic efficiency curve, Nuclear Inst. and Methods in Physics Research, A. (941) (2019) 162305.
 IAEA Technical Document 1497, Classification of soil systems on the basis of transfer factors of radionuclides from soil to reference plants, 2006.
 IAEA Technical Report Series, Handbook of parameter values for the prediction of radionuclide transfer in terrestrial and freshwater envinronment 472 (2010).
 C. Dovlete, P.P. Povinec, Quantification of Uncertainty in Gamma-spectrometric Analysis of Environmental Samples.Quantifying Uncertainty in Nuclear Analytical Measurements.IAEA-TECDOC-1401. IAEA, Vienna, 2004.
 F.E. Diebold, S. McGrath, Investigation of Artemisia tridentataas a biogeochemical uranium indicator. J. Geochem. Explor. 23 (1985) 1–12.
 S.C. Sheppard, W.G. Evenden, The assumption of linearity in soil and plant concentration ratios: an experimental evaluation. J. Environ. Radioact. 7 (1988) 221–247
 C.E. Dunn, Application of biogeochemical methods to mineral exploration in the boreal forests of central Canada, In Carlisle, D. et al (ed), Mineral exploration: Biological systems and organic matter, Prentice Hall, Englewood Cliffs NJ, 1986.
 Drobkov, Radiological Health Data, U.S. Public Health Service. 5, 1964, 12, 579.