Background contribution to internal contamination.
Intakes of Radionuclides : Occupational and Public Exposure. Workshop. Avignon, FRA, 1997/09/15.
The northern part of the state of Rio de Janeiro is characterised by the presence of large deposits of monazite sand.
In this region a monazite sand extraction plant is located, which has been in operation for more than 25 years.
In order to analyse the background contribution to the internal contamination, 72 inhabitants of this region were monitored by excreta analysis.
Some people have contributed with more than one sample to the study.
In the high background radiation area it was possible to detect significant amounts of 232Th in urine samples suggesting a chronic thorium incorporation.
In'normal'background areas, as in the city of Rio de Janeiro, the amount of 232Th excreted in urine is not significant.
The average 232Th concentration in faeces of the non-exposed population is about one third of the average of 232Th concentration in faeces samples from the workers and twice the average concentration in faeces samples from inhabitants of the city of Rio de Janeiro.
The results indicate that the thorium intake is influenced by the place of residence and show how important it is to characterise the region where workers live when occupational control is carried out.
Mots-clés Pascal : Radiocontamination, Monitorage, Excrétion, Dosimétrie, Thorium, Exposition professionnelle, Rétention, Distribution dose, Brésil, Amérique du Sud, Amérique
Mots-clés Pascal anglais : Radioactive contamination, Monitoring, Excretion, Dosimetry, Thorium, Occupational exposure, Retention, Dose repartition, Brazil, South America, America
Notice produite par :
Inist-CNRS - Institut de l'Information Scientifique et Technique
Cote : 99-0011347
Code Inist : 002A08F03. Création : 31/05/1999.