[en] A comparison between the environmental impact by nuclear facilities with the burden suffered from natural radioactivity calls for studying the long-lived radionuclides of the U-238 and Th-232 decay series U-238, U-234, Th-232, Th-230, Th-228, Ra-228, Ra-226, Pb-210 and Po-210. This work describes the development of a fast isotope dilution analysis method allowing to separate with one sample solution U, Th, Ra, Pb and Po both from each other and, at the same time, from the matrix. To test its applicability, the method was used with samples consisting of soil, sediments, plants, water, carbon and air dust filter. The detection limit for the chemical yield attained of approx. 70% was 0.27 mBq per sample for Th-232, Th-230, Th-228, U-238, U-234 and Po-210. The detection limit for Pb-210 was 10 mBq per sample. On account of the influence by Ra-226 in the Ra-228 measurement and vice versa the detection limit is a function of the Ra-226 and Ra-228 concentrations, respectively, in the sample. The detection limits for the pure nuclides are 0.9 mBq per sample and 10 mBq per sample, respectively, for Ra-226 and Ra-228. (orig./HP)

[en] A spectrophotometric determination of thorium with arsenazo III (1,8 dihidroxynaphtaline - 3,6 sulfanic acid - 2,7 bis (azo-2) - phenil argonic acid) was carried out aiming to analyse this element in water. In order to eliminate possible interferences, a coprecipitation with lantanium fluoride was used followed by an extration with 0,2 M TTA (tenoil-trifluor - aceton) / Benzen. The results showed a good agreement with the ones obtained by alfa-spectrometry. (Author)

[en] The determination of Pb-210 and U-238 by γ spectrometry in environmental samples was carried out using the 47 KeV (4%) line for Pb-210 and the 63 KeV (3,9%) line from Th-234 to U-238. An intrinsic Ge detector with 0,8 KeV resolution for the 60 KeV line of Am-41 was employed. The eficiency was determined by using the radionuclide water solution. The samples were measured in a cylindric geometry with 7 cm diameter and 3 cm hight with a mass ranging from 25 to 180g, depending on the density. The self absorption correction factor for each sample was determined by using an external source of Pb-210 and Am-241. The results showed good agreement with the radiochemical analysis values. The diferences were lower than 20%; the detection limit changed from sample to sample staying on the pCi/g range for the 200 minutes couting time. (Author)

[en] A method of analysis was developed for U-238, U-234, Th-232, Th-230, Th-228, Ra-228, Ra-226, Pb-210 and Po-210 starting from a same sample-solution. The chemical separation U/Th/Pb/Po/Ra was based on chromatographic extraction. (E.G.)

No abstract available

No abstract available

[en] Published in summary form only

[en] The occurrence of relatively high concentrations of radionuclides in certain spring waters has been of interest to researchers on natural radioactivity and radioprotection including in Brazil. Twenty four springs known in the Pocos de Caldas plateau were analysed and investigated for their concentrations on U-238, U-234, Th-232, Th-230, Th-228, and Ra-226. The highest activity concentrations were found in waters from Aguas da Prata, in the rim of plateau, where values up to 2,4 Bq/l of Ra-226 were measured. (author)

[en] A method of sequential analysis was developed aiming to determine U-238, U-234, Th-232, Th-230, Th-228, Ra-226 and Ra-228 in environmental samples, and was applied to the analysis of mineral waters from the Pocos de Caldas Plateau. The highest values were found in samples from Aguas da Prata city, which had up to 63 pCi Ra-226/1. The minimum detectable activities were lower than 0,1 pCi/1 for uranium and thorium isotopes and about 0,5 pCi/1 and 2pCi/1 for Ra-226 and Ra-228 respectively. (Author)

[en] The concentration of Cs, Fe, Cr, and Co in macroalgae locally abundant in the Piraquara de Fora bay -Angra dos Reis, Nuclear Power Plant Region, R.J. Brazil was been determined using neutron activation analysis. The results demonstrated that the studied species of macroalgaes can be employed as useful monitors for routine or accidental radionuclides releases. (Author)