Source Water Protection
Radium in Minnesota’s Paleozoic Bedrock Aquifers
Radium is a naturally-occurring metal that is common in groundwater pumped from sandstone bedrock aquifers of southeastern Minnesota. Drinking water containing radium may cause cancers of the blood and bone. For this reason, the federal Maximum Contaminant Level (MCL) for radium is 5 picocuries per liter (pCi/L).
The patterns of radium occurrence have been studied in two important Minnesota sandstone aquifers. Further information can be found below.
The Minnesota Geological Survey first determined the occurrence of radium in the Mt. Simon-Hinckley Sandstone aquifer in a 1992 report. The report concluded that radium is widespread and commonly close to or above the MCL (5 pCi/L). Further information can be found here:
Radium occurs sporadically at high levels in the Jordan Sandstone. To accurately define the radium distribution in the Jordan Aquifer, MDH carried out a sampling plan in coordination with Duke University during 2008-2011. Further information can be found here: