Workplaces with natural radionuclides – investigation results from Bavaria

Abstract

Abstract Since the amendment of the German Radiation Protection Ordinance in the year 2001 special workplaces with increased exposure due to natural terrestrial radiation have been subject to legal regulations. After the Radiation Protection Ordinance came into force the Bavarian Environment Agency informed all water supply facilities, breweries, dairies, mineral water manufactures, operators of underground workplaces and radon spas that the annual radon exposure of their staff has to be estimated. In Bavaria approximately 3330 companies with workplaces with exposure to radon were investigated. Herein the water supply facilities represented the largest group with 2550 companies. In about 96 % of all investigated companies the radon exposure of the staff is below the action level of 6 mSv per year. In 75 water supply facilities and two mines the radon exposure of the staff exceeded the action level (6 mSv/a) or the annual limit (20 mSv/a). Workplaces with increased exposure due to uranium and thorium are of secondary importance in Bavaria. Within the scope of a research project 13 companies were found, that still use thoriated welding electrodes. Only a few facilities use thoriated mantles, thorium alloys or natural thorium and uranium. The effective dose of all examined workers was below the action level of 6 mSv per year.