The presence of some artificial and natural radionuclides in a Eucalyptus forest in the south of Spain

Long-lived artificial radionuclides (Cs-137, Sr-90) were studied in a Eucal yptus plantation located in the south-west of Spain. Radionuclide concentra tions were determined in different types of samples corresponding to specif ic forest components (soil, trees, herbs and litter). Depth profile distrib utions were obtained in two selected core soils. Two layers were separately measured in three other cores. The concentration factor, defined as the ra tio between the mean activity concentration in a component and the mean act ivity concentration in the soil, was calculated for each component. The bio mass of different components was estimated in order to evaluate the total d ensity concentration (Bq/ha) of the artificial radionuclides (Cs-137, Sr-90 ) in the Eucalyptus plantation. The transfer of the radionuclides between t he different forest components can be inferred from the results. Additional ly, other naturally occurring radionuclides (K-40, Ra-226, Ra-228, Ac-228) were determined for comparison. Transport of radionuclides from forest to a nearby pulp mill is also discussed. (C) 2001 Elsevier Science Ltd. All rig hts reserved.