Uranium in drinking water, naturally

Abstract

Natural uranium consists almost entirely of the uranium 238 isotope in its hexavalent state, which commonly associates with oxygen as the uranyl ion UO₂²⁺. It decays by both alpha (i.e., nucleus of a helium atom) and gamma (i.e., high-energy photon) emissions. Relative to other radionuclides, natural uranium has a low level of radioactivity because of its extremely long half-life (4.5 billion years).