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Radiation and Environmental Biophysics

, Volume 36, Issue 1, pp 31–37 | Cite as

137Cs mobility in soils and its long-term effect on the external radiation exposure

  • K. Bunzl
  • P. Jacob
  • W. Schimmack
  • R. M. Alexakhin
  • N. P. Arkhipov
  • Y. Ivanov
  • S. V. Kruglov
ORIGINAL PAPER

Abstract

To predict the external gamma-dose rate of Chernobyl-derived 137Cs for a period of about 100 years after its deposition, the vertical distribution of radiocesium in several meadow soils in the Chernobyl area and in Germany was determined, and the corresponding residence half-times of this radionuclide in the various soil layers were evaluated using a compartment model. The resulting residence half-times were subsequently used to calculate the vertical distribution of 137Cs in the soil as a function of time and finally to predict the external gamma-dose rates in air for these sites at various times. A regression analysis of the data obtained showed that the time dependence of the relative gamma-dose rate in air D(t) at the Chernobyl sites can be described by an exponential equation D(t) = a + b ⋅ exp(–t/c), where t is the time after deposition. For the ten German sites the best fit was obtained using the two-exponential equation D(t) = a ⋅ exp(–t/b) + c ⋅ exp(–t/d). The gamma-dose rate of 137Cs at the Chernobyl sites decreases significantly more slowly with time than at the German sites. This means that after e.g. 30 years the mean relative gamma-dose rate at the German sites will have decreased from 100% (corresponding to an infinite plane source on a smooth surface) to 9% (95% confidence interval 8%–10%), while at the sites in the Chernobyl area it will have decreased only to 21% (20%–23%). This difference is the result of the longer residence half-times of 137Cs in the soils at the Chernobyl sites. All results are compared with estimates from earlier studies.

Keywords

Time Dependence Soil Layer Radiation Exposure Smooth Surface Vertical Distribution 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1997

Authors and Affiliations

  • K. Bunzl
    • 1
  • P. Jacob
    • 1
  • W. Schimmack
    • 1
  • R. M. Alexakhin
    • 3
  • N. P. Arkhipov
    • 2
  • Y. Ivanov
    • 4
  • S. V. Kruglov
    • 3
  1. 1.GSF – National Research Center for Environment and Health, D-85764 Neuherberg, GermanyDE
  2. 2.Pripyat Research Centre and Technical Industrial Association, 10 Karl Liebknecht St, Chernobyl, UkraineUA
  3. 3.Russian Institute of Agricultural Radioecology, 1 Kievskoe St, Kaluga, Obninsk, Russian FederationRU
  4. 4.Ukrainian Institute of Agricultural Radiology, 255205, Machinostroitelej st, 7, Chabani, Kiev Region, UkraineUA

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