Radium-226 in Drinking Water

Radium-226 is a naturally occurring radioactive element that forms as part of the uranium decay chain. It is found in many types of rock and soil and dissolves into groundwater, particularly in areas with sandstone aquifers, phosphate-rich geological formations, and granite bedrock. Once ingested through drinking water, radium behaves like calcium in the body -- it is absorbed into bones and teeth, where it continues to emit radiation for years. This makes it a uniquely dangerous contaminant because the radiation source becomes embedded in your body.

The primary health risk from radium-226 in drinking water is bone cancer. Because radium accumulates in bones, the alpha radiation it emits directly damages the surrounding bone tissue and marrow over time. Studies of radium exposure, dating back to the tragic cases of the "Radium Girls" who painted watch dials with radium paint in the 1920s, have definitively established the link between radium ingestion and bone cancer, as well as cancers of the head (sinuses and nasal passages). The EPA's MCLG of zero reflects the fact that any exposure to radium carries some cancer risk.

The EPA regulates combined radium-226 and radium-228 at 5 picocuries per liter (pCi/L). Many Midwestern and Southern states have widespread radium contamination in groundwater, including parts of Illinois, Wisconsin, Iowa, Texas, Florida, and the Carolinas. Community water systems in these areas sometimes struggle with compliance, and smaller systems may lack the treatment infrastructure to effectively remove radium. If your water system has reported radium detections in its Consumer Confidence Report, it's worth understanding the levels and considering additional home treatment.