Radiological Impacts of NORM in the Environment and Workplaces

Full text: Among the sources of natural radioelements, which were detected not being connected with the nuclear industry, there were found during energy production using fossil fuels and the phosphate industry. The chemical or physical processing may increase the concentrations of the radioactive components (from the raw materials), in the end products, by-products and the wastes. The aim of this study has been to assess the exposure of both workers and members of the public due to these two industries involving Naturally Occurring Radioactive Materials (NORM). Between 1996-1999 we have studied four modern and representative coal-fired power plants (CFPPs) and one phosphate fertilisers plant (PFP). Knowing that the pathways of exposure of workers and population are gamma external irradiation, dust and radon inhalation, within the framework of the study we have proceeded as follows. There were extensively measured the levels of natural radioactivity in coal, sedimentary phosphate rock, fertilisers, phosphogypsum, slag, ash, dust and air at workplaces and in the environmental components (air, soil, water, vegetation). The workers in the phosphate industry receive the highest total effective doses from inhalation of radon, thoron and their progeny, as well as from external exposure. The exposure in workplaces could be responsible for 3x10-2 potential radiation induced fatal cancers in 298 workers from CFPPs and 10-2 cases in 151 workers from PFP. For workers in CFPPs the higher risk is associated with the intake of thorium-232 while in PFP the higher risk is associated with the intake of radium-226 and uranium-238. Our study had clearly shown the increase of the natural radioactive content in the environmental components, therefore of irradiation, only in the neighbourhood area of CFPPs. (author)