Environmental Burden of NORM Residues

The monitoring and prevention of occupational radiation risk caused by NORM has in many cases become obligatory for industries of concern. Usually, the degree of control applied in such cases has been based on conventional radiation protection standards as applied to radiation risks from artificial sources. Case specific risk scenarios have been developed and have become readily available to industry operators. Far less attention has been paid to the environmental burden of NORM residues that have been designated as waste. Such waste is often deposited directly into the environment, a practice that is forbidden in the case of radioactive waste containing radionuclides of artificial origin. Hence, to assess the environmental impact, it is essential to have information on the radionuclide species deposited, interactions within affected ecosystems and the time dependent distribution of radionuclide species influencing mobility and biological uptake. Preliminary data have indicated a strong need to consider such waste as a specific type of environmental hazard. But NORM residues differ significantly in quantity and quality from 'classical' nuclear materials and, moreover, the derived radiation risk is usually associated with the risk caused by other pollutants. That is why they cannot be controlled by applying directly the standards designed and developed for radioactive waste containing radionuclides of artificial origin. Such a situation results in there being no precise regulations in this area and the non-nuclear industry is not aware of the environmental problems caused by NORM residues. This paper discusses all aspects of the radiation risk to the environment caused by NORM residue deposits that have not been regulated from a radiation protection point of view. The inconclusive nature of existing recommendations and models of radiation risk assessment are underlined. General terms such as the environmental effect, and the basic parameters necessary to carry out a consistent and comparable environmental risk assessment have been developed and defined. (author)