TABLE OF CONTENTS Naturally occurring radioactive materials (NORM) are part of the Earth. The majority of radionuclides in NORM (principally radium and radon) arise from uranium and thorium decay. Radon exposure in homes can be high, particularly those built on Rn-containing rocks such as in SW England and the Peak District in Derbyshire as the gas continuously accumulates and may achieve potentially dangerous concentrations. Human activities and technological processes such as fossil fuel burning, mineral extraction and fertiliser application often increase concentrations of radionuclides in the NORM. Industrial practices involving natural resources often concentrate radionuclides to a degree that may pose a risk to humans and the environment. Materials that contain natural radionuclides, whose levels are concentrated due to technological operations, are termed technologically enhanced naturally occurring radioactive materials (TENORM). TENORM are, in many cases, large-volume, low-activity waste streams produced by industries such as mineral mining, ore beneficiation, phosphate fertiliser manufacture, water treatment and purification, paper and pulp manufacture, oil and gas production, scrap metal recycling and waste incineration. The level of individual exposure from NORM is usually trivial. However, TENORM in some cases can be dangerous and classified as radioactive waste.
Primordial radionuclides are typically long lived, with half-lives often of the order of hundreds of millions of years. Primordial radionuclides are classified as non-series and series depending on the decay pathway. Two primary non-series primordial radionuclides are 40K and 87Rb whose basic properties are given in Table 5.1.
