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Radionuclides: Natural

  1. Dominic Larivière,
  2. Nicolas Guérin

Published Online: 15 JUN 2010

DOI: 10.1002/0470862106.ia700

Encyclopedia of Inorganic Chemistry

Encyclopedia of Inorganic Chemistry

How to Cite

Larivière, D. and Guérin, N. 2010. Radionuclides: Natural. Encyclopedia of Inorganic Chemistry. .

Author Information

  1. Université Laval, Québec, QC, Canada

Publication History

  1. Published Online: 15 JUN 2010

Abstract

The natural ionizing radiation present on our planet comes from many sources and generates most of the radioactivity that surrounds us. Primordial radionuclides, defined as radionuclides present since the formation of Earth about 4.6 × 109 years ago, play a critical role in our understanding of geological conditions on our planet over its whole history. Radioactivity initiated by the successive decay of 232Th, 235U, and 238U is essentially responsible for the presence of radioisotopes of lead, polonium, bismuth, astatine, radon, francium, radium, and protactinium on Earth. Because of their short half-lives with respect to Earth's geologic timescale, the decay of these radionuclides is responsible for a significant portion of the doses of natural radioactivity received by humans. Cosmic radiation, originating from both within and beyond our solar system, completes the list of significant modes of production of natural radioactivity in the atmosphere and the lithosphere. Minor sources of natural radioactivity (including radionuclides produced by cosmic neutron bombardments and spontaneous fission in uranium and thorium minerals) are known to generate quantities of transuranium isotopes and fission products, which are generally associated with the development of nuclear power.

Keywords:

  • natural radioactivity;
  • radioactive disintegration;
  • cosmic radiation;
  • cosmogenic;
  • primordial;
  • decay series;
  • actinides;
  • fission products;
  • technologically enhanced naturally occurring radioactive materials (TENORM);
  • geological events;
  • environmental sources