Please refer to the Dutch or French webpages for a brief introduction on radioactivity, or consult the UNEP booklet 'Radiation: effects and sources'. This publication is largely based on the findings of the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), a subsidiary body of the United Nations General Assembly and for which the United Nations Environment Programme provides the secretariat. This publication is also available on other languages, such as Dutch, French and German. In cases of discrepancy, the original English text will prevail.