Determination of internal doses to workers exposed to suspended radioactive dust in the ceramic industry by radiochemical methods

Abstract

[EN] Zircon products used as raw materials in the ceramic industry are NORM ("Naturally Occurring Radioactive Material") and can be found in suspended powder form mainly in the zircon sand milling plants. They can generate internal doses by inhalation to exposed workers. To assess such internal doses, personal aerosol filters were collected from zircon sand milling plants from Spain and analyzed by a radiochemical method for 238U and 232Th chains activity estimation by alpha spectrometry. This work presents the improvement in the accuracy of the assessment of internal doses received by different homogeneous exposure groups in several milling plants compared to previous work. The method allows the analysis of small amount of sample and with no equilibrium in the chain. With the method proposed, a reduction in the dose between 23 and 63% was obtained, in comparison with the doses considering the activity of the materials used. Significant differences in uranium and thorium activities of the aerosol dust analyzed depending on the industry were observed, and also for the different homogeneous exposure groups.