The term NORM exists also to distinguish ‘natural radioactive material’ from anthropogenic sources of radioactive material, such as those produced by nuclear power and used in nuclear medicine, where incidentally the radioactive properties of a material maybe what make it useful. These elements have always been present in the Earth's crust and atmosphere, and are concentrated in some places, such as uranium orebodies which may be mined. Long-lived radioactive elements such as uranium, thorium and potassium and any of their decay products, such as radium and radon are examples of NORM. Concentrations of actual radionuclides may or may not have been increased if they have, the term technologically-enhanced NORM (TENORM) may be used. However, the term is used more specifically for all naturally occurring radioactive materials where human activities have increased the potential for exposure compared with the unaltered situation. NORM potentially includes all radioactive elements found in the environment.
Material giving rise to these enhanced exposures has become known as naturally occurring radioactive material (NORM). However, certain work activities can give rise to significantly enhanced exposures that may need to be controlled by regulation. For most human activities involving minerals and raw materials, the levels of exposure to these radionuclides are not significantly greater than normal background levels and are not of concern for radiation protection. The most important for the purposes of radiation protection are the radionuclides in the U-238 and Th-232 decay series. Radon in homes is one occurrence of NORM which may give rise to concern and action to control it, by ventilation.Īll minerals and raw materials contain radionuclides of natural origin.Uranium mining exposes those involved to NORM in the uranium orebody.NORM results from activities such as burning coal, making and using fertilisers, oil and gas production.Radioactive materials which occur naturally and where human activities increase the exposure of people to ionising radiation are known by the acronym 'NORM'.Naturally-Occurring Radioactive Materials (NORM)
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