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  • 1 Universität Regensburg Institut für Biophysik und physikalische Biochemie 93040 Regensburg Germany
  • | 2 Universität Regensburg Laboratory for Environmental Radioactivity, Institut für Organische Chemie 93040 Regensburg Germany
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The uptake and the radial distribution of naturally occurring radionuclides in the tree rings of a spruce tree were examined. The activity concentrations of Pb-210 are at a constant level of about 1,7 Bq/kg dry weight (dw) in older tree rings but decrease to younger ones. We suggest that Rn-222 dissolved in the soil water is taken up in significant amounts by the tree roots and decays to Pb-210 within the wood. The activity concentrations of Ra-226 of about 2,0 Bq/kg (dw) are nearly constant over all tree rings. Ra-228 however showed a significantly different behavior. Futhermore the activity concentrations of U-, Th- and Pu-isotopes were determined. A depth profile of the soil within the root zone of the spruce gives further informations.