Occupational exposure to natural ionizing radiation in workplace of ceramic factory

The ceramic industry is one of the major consumers of zircon sands used as raw materials in the composition of the tiles. These materials, considered as NORM have radioactivity concentrations significantly higher than the world average noticed in soils and rocks (the average activity concentrations of 238U and 232Th in zircon sands are 3000 and 600 Bq kg-1, respectively). Furthermore, normal industrial practices may increase the concentration of these elements to levels where special precautions are needed for handling, storing, transporting, and disposing of the zircon materials Annual limits to the maximum amount of occupational exposure are enforced by Italian national law (Legislative Decree n. 241/00): these limits prevent any worker from being exposed to levels of radiation which exceed all acceptable risk for their occupation or activity. The present paper deals with the calculation of occupational exposure to natural ionizing radiation in a ceramic factory. Results obtained indicates that the values of annual effective dose E (mSv), calculated for a “standard” worker is 0.4 mSv (the contribution of dust inhalation on the total dose is 30% and the external exposure is 70%).