Radioactive materials are called radionuclides. They come from natural and human-made sources. When radionuclides break down, they give off radiation.
Small amounts of radiation are common in the air, soil, bedrock, surface water and groundwater. Because of this, radionuclides can also be found in drinking water.
Health concerns
Radionuclides that can be found in drinking water are gross (total) alpha and radium. Long-term exposure to either may cause health problems. These include an increased risk for certain types of cancers and kidney damage.
However, there are no immediate health risks or symptoms from drinking water. Because radionuclides cannot pass through skin, using the water for showering, washing or other daily activities is not a health risk.
Testing for radionuclides
The number of radionuclides in water can vary. This is because the Earth's crust has different amounts of radioactive elements in different places.
Community public water systems must test for radioactive contaminants. In Dakota County, some city drinking water wells have had levels above the Environmental Protection Agency's Maximum Contaminant Level.
You can find test results and information about any violations on your city's website or in your city's Consumer Confidence Report.
Find your city's drinking water information on the Dakota County Drinking Water webpage.
Dakota County tested some private wells through the Ambient Groundwater Quality Study.
Map of gross alpha levels in Dakota County wells
Map of radium levels in Dakota County wells
Radionuclides in private wells
Private wells do not have to be tested for radionuclides. You cannot see, smell, or taste radioactive elements in water. Testing is the only way to know if they are present.
If you are concerned about radionuclides in your private well, have your water tested. There is one testing option available for gross alpha and radium.
Wisconsin State Lab
- Request a test kit by calling 608-224-6203 or visit the Wisconsin State Lab website.
- You must collect and ship a one-gallon water sample.
- Expedited shipping is required. The sample must arrive at the lab within five days.
- Cost: $87 for the gross alpha test and $314 for the radium test.
- Results may take up to two months.
Water treatment devices
You may already have a device that reduces radionuclides.
- Reverse osmosis system can reduce gross alpha and radium.
- Ion exchange devices, such as a water softener, can reduce radium.
More treatment options for radium are listed on Page 3 of the state's Home Water Treatment fact sheet.
If you are concerned about exposure and do not use a treatment device, you may test your water or install treatment. You can find a licensed water conditioning professional.
If you install a treatment system, consider testing your water again. This makes sure the system is reducing radionuclides to safe levels.
If you are not sure whether your main drinking water tap is softened, you can request a hardness test strip. Call Dakota County Environmental Resources at 952-891-7000 to have one mailed to you or pick one up at the Robert Trail and Inver Glen libraries.
Radon air testing
Radon is a radionuclide in gas form. According to the Minnesota Department of Health, there is no link between radionuclides in water and indoor radon levels.
However, Dakota County Public Health recommends that every home be tested for radon. Two out of 5 homes in Dakota County have high radon levels. To get a radon test kit, visit the Dakota County Radon webpage.
For more information