Radium Fact Sheet

Radium is formed when uranium and thorium undergo radioactive decay in the environment. Uranium and thorium are found in small amounts in most rocks and soil. Radium is constantly being produced by the radioactive decay of uranium and thorium. Two of the main radium isotopes found in the environment are radium-226 and radium-228 with an atomic weight of 226 and 228. Radium has been used as a radiation source for treating cancer, in radiography of metals, and combined with other metals as a neutron source for research and radiation instrument calibration. Surface water sources and shallow wells will typically have lower levels of radium while deeper wells may at times have higher concentrations, depending on several natural factors.