Abstract

Radionuclides undergo radioactive decay through emission of alpha and beta particles or gamma rays. There are about 2000 known radionuclides present in the earth. These naturally occurring radionuclides are ubiquitous trace elements found in rocks and soils. In general, radionuclides can be categorized in two ways: (1) by type of radioactive decay (alpha, beta, or gamma emission) and (2) by naturally occurring or manufactured. The radioactive elements are also present in water. The presence of radioactive elements in the groundwater depends on the geology and geochemistry of the rock formation. Groundwater is one of the likely pathways for radionuclide transport during accidental releases from nuclear facilities, such as power plants, fuel processing plants, and mining or milling operations. This can be estimated by direct measurement of activity or using mathematical models or a combination of these techniques.