Published 1989 | Version v1
Miscellaneous Open

Development of an in vitro bioassay method to determine the intake q natural thorium

Creators

Description

A simple and economic method for analytical determination of the Th-232 concentration in excreta samples (urine and feces) was developed, using Th-229 as a tracer. Solvent extraction followed by alpha spectrometry was employed. The minimum activity detectable for urine samples was (0,36 ± 0,05) mBq/dm3 and for fecal samples (0,52 ± 0,12) mBq/dm3. Two groups of persons were analyzed. The first one, A, contituted by persons non ocupationally exposed and the second one, B, by workers ocupationally exposed. The results of thorium concentration in excreta samples from group A were compared with the daily excretion due to alimentary diet of thorium and the results obtained from the second group were compared with the limits of excretion derived from the annual limits of intake recommended by the ICRP. All the samples analyzed showed thorium concentration levels bellow the limits recommended by the ICRP. (author)

Availability note (English)

MF available from INIS under the Report Number.

Abstract (Portuguese)

Um metodo simples e economico foi desenvolvido utilizando a extracao quimica por solvente, seletiva para o torio, seguida de espectrometria alfa. Como tracador utilizou-se o isotopo de 229Th. Foram analisadas amostras de excretas (urina e fezes) para a determinacao do 232Th e a atividade minima detectavel foi de (0,36 ± 0.05) mBq/dm3 para urina e de (0.52 ± 0,12) mBq/dm3 para fezes. Dois grupos de servidores foram submetidos a esta analise, o primeiro grupo, A, constituido de pessoas nao ocupacionalmente expostas e o segundo grupo, B, constituido de pessoas ocupacionalmente expostas. Os resultados apresentados pelo grupo A foram comparados com a dieta alimentar do torio sugerida pela Comissao Internacional de Protecao Radiologica e o grupo B, com os limites de excrecao originados dos limites de incorporacao anual recomendados pela propria Comissao Internacional. Constatou-se que todas as amostras analisadas apresentaram niveis de concentracao de 232Th inferiores aos limites derivados de excrecao recomendados. (autor)

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Additional details

Additional titles

Original title (Portuguese)
Desenvolvimento de um metodo de bioanalise in vitro para a determinacao de torio natural incorporado

Publishing Information

Imprint Pagination
92 p.
Report number
INIS-BR--2229

INIS

Country of Publication
Brazil
Country of Input or Organization
Brazil
INIS RN
21079386
Subject category
S62: RADIOLOGY AND NUCLEAR MEDICINE;
Resource subtype / Literary indicator
Thesis
Descriptors DEI
CHEMICAL ANALYSIS; FECES; THORIUM 229; THORIUM 232; TRACER TECHNIQUES; URINE
Descriptors DEC
ACTINIDE NUCLEI; ALPHA DECAY RADIOISOTOPES; BIOLOGICAL MATERIALS; BIOLOGICAL WASTES; BODY FLUIDS; EVEN-EVEN NUCLEI; EVEN-ODD NUCLEI; HEAVY NUCLEI; ISOTOPE APPLICATIONS; ISOTOPES; MATERIALS; NUCLEI; RADIOISOTOPES; SPONTANEOUS FISSION RADIOISOTO; THORIUM ISOTOPES; WASTES; YEARS LIVING RADIOISOTOPES