Radium-226 and -228 are radioactive elements that enter water from eroding rock and soil. These naturally occurring contaminants increase the risk of cancer.

Combined Radium (-226 & -228) occurs naturally in the environment, primarily in rocks and soil. As water moves through deposits containing these radioactive isotopes, it can dissolve and carry them into groundwater sources. The presence of radium in drinking water is typically measured in picocuries per liter (pCi/L). While radium is found in trace amounts across the U.S., some regions have higher concentrations due to their geological makeup. Regular testing and treatment methods like ion exchange or reverse osmosis can help reduce radium levels in public water supplies.