Natural radionuclides in an eucalyptus forest located in the south of Spain

A pulp mill and the forest from which the raw material for its operation is collected have been studied since 1992 with respect to the natural radioactivity involved. The activity concentrations of 234U, 238U, 228Th, 230Th, 232Th in forest samples (soils, wood, barks), were determined using alpha and gamma spectrometry. Radium and thorium isotopes were analyzed using the conventional radiochemical method. For gamma spectrometry, the HPGe detector efficiency was determined using the generalized transmission method developed by Bolivar et al. The results obtained by the two techniques are presented. The natural radionuclide distribution, activity ratio and relative activities among the forest compartments (soil, wood and barks) are given