Definitions for "Radionuclides"
Radioactive elements. These may be subdivided into natural radionuclides such as radium or uranium which are normally present in the earth, or artificial radionuclides which are not normally present (or normally present in very small amounts) and are produced by nuclear fission.
Radioactive material capable of giving off radiant energy in the form of particles or rays as alpha, beta and gamma rays by the disintegration of atomic nuclei.
Any man-made or natural element that emits radiation and that may cause cancer after many years of exposure through drinking water.