Natural Radioactivity in Fresh Water System

Abstract

Measurement of natural radioactivity in drinking water has been performed for the assessment of the doses and the risks resulting from consuming water. Ingestion is a major pathway for internal exposure; hence, the measurement of radioactivity in drinking water is relevant. The dose contribution is primarily due to the presence of naturally occurring radionuclides of the uranium and thorium series. It is observed that the most natural radioactivity present in drinking water consists of the decay chain of the U and Th series. Among naturally occurring radionuclides, ²²⁶Ra and ²²⁸Ra are biologically significant due to their long radiological and biological half-life. ²²⁶Ra, an alpha emitter, with a half-life of 1622 years is produced by the decay of ²³⁸U, and ²²⁸Ra a long-lived beta emitter (half-life 5.7 years), is produced by the decay of ²³²Th. Thus, the distribution of ²²⁶Ra and ²²⁸Ra is the function of U and Th content in drinking water.