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Fact Sheet- Alpha Radiation

What is Alpha Radiation?

Alpha radiation is one of the types of energy released when certain radioactive elements decay or break down over time. Radioactive elements such as uranium and thorium are found naturally in rocks and minerals in the earth's crust in varying amounts. Uranium and thorium slowly transform into radium and radon over millions of years through the release of energy. One form of this energy is alpha radiation.

Why is alpha radiation in drinking water supplies?

Groundwater flows through rocks, sediments, and soils and often accumulates in underground water "bodies" called aquifers. Well drillers try to penetrate into aquifers to construct drinking water wells. Some bedrock formations naturally have elevated amounts of radioactive elements that may dissolve into groundwater and be carried in solution to an aquifer. The continual decay of radioactive elements in groundwater results in the emission of alpha radiation. Radon gas may also be dissolved with uranium and radium in groundwater. Approximately 60% of Vermonters obtain their drinking water from wells.

How would I know if my drinking water contains alpha radiation?

Community public wells are tested for mineral alpha radioactivity by using a test called "gross alpha activity". If the gross alpha results are above public drinking water standards, the water system is notified and a plan is developed to reduce levels. Private well owners can purchase a kit to have their water tested for gross alpha activity at the Vermont Department of Health Laboratory and at other approved laboratories. Kits for measuring radon in drinking water and air are also available.

What is Vermont's drinking water standard?

Alpha radiation is measured in picocuries per liter (pCi/L). The U.S. Environmental Protection Agency has set maximum contaminant levels of 15 pci/liter for adjusted gross alpha and 5 pci/liter for combined radium 226 and 228 in drinking water. Adjusted gross alpha is the total alpha counts minus alpha counts from uranium and radon. Public water supplies in Vermont are required to test periodically for adjusted gross alpha and, if necessary, radium 226 and 228, uranium, and radon. Although the U.S. EPA sets the upper limit for uranium in community public wells at 30 micrograms per liter, the Vermont DEC Drinking Water and Groundwater Protection Division adopted a stricter level for public water supply of 20 micrograms per liter (µg/L). See Water Supply Rule, 2010, p.39

Private well owners are not required to test for drinking water radioactivity. If a homeowner decides to test his or her well, an unadjusted gross alpha test is the first step. Unadjusted gross alpha generally measures alpha radiation from uranium, radium, and radon. If unadjusted gross alpha is measured at or above 5 pCi/L in your home well, additional testing is suggested to pinpoint the source. For more information, contact the Vermont Department of Health or the Department of Environmental Conservation, Water Supply Division at (800) 823 6500.

What are the health concerns associated with alpha radiation?

There are no immediate health risks or symptoms from drinking water with above-standard alpha radiation; however, it may cause health problems over a lifetime. Because alpha radiation is weak, it doesn't pass through skin and is not a hazard unless ingested. Lifetime consumption of water with elevated levels of radium and uranium increases one's risk of bone cancer and kidney damage, respectively.

Well water that contains elevated levels of dissolved radioactive elements may also contain radon gas that could increase radon levels in the air inside a home. Actions like taking showers, doing laundry or running a dishwasher can release radon into the air inside your home. Homes with elevated gross alpha levels in drinking water may also have problems with radon seeping into the basement. Breathing air with elevated levels of radon over a lifetime increases a person's risk of getting lung cancer.


EPA Level


Health Effect

Combined radium 226/228

5 pCi/L

Naturally occurs in some drinking water sources

Some people who drink water with elevated levels of radium over many years may have an increased risk of getting cancer

Adjusted Gross Apha

15 pCi/L

Naturally occurs in some drinking water sources

Some people who drink water with elevated levels of alpha emitters over many years may have an increased risk of getting cancer


30 m g/L***

Naturally occurs in some drinking water sources

Exposure to uranium in drinking water may result in toxic effects to the kidney. Some people who drink water with elevated levels of alpha emitters over many years may have an increased risk of getting cancer

Source: US EPA Office of Water
*** Vermont Public Water Supply level is 20 µg/L for uranium (2010)


Can the levels of alpha radiation in my drinking water be reduced?

Yes. There are several treatment options available to help reduce the levels of gross alpha radiation in drinking water. To determine the most effective treatment, the source of the alpha radiation must be identified. Because alpha radiation can come from a variety of sources, more than a single test may be needed.

  • If the gross alpha result is less than 5 pCi/L, no further testing or treatment is necessary.
  • If the gross alpha result is 5-15 pCi/L, test for radium 226 and 228.
  • If the gross alpha result is greater than 15 pCi/L, test for radium 226, radium 228 and uranium.

What are my treatment options?

Solving an alpha radiation problem can be complex. Radon and uranium are not yet regulated and there continues to be discussion among scientists and regulators about the acceptable amount of radon and uranium in drinking water supplies. Also under discussion are future government requirements for disposal of radioactive wastes.

  • Radium - Consider treatment when test results show that the total radium 226 and 228 is 5 pCi/L or higher. A water softener (also called a cation exchanger) can be used to remove radium from drinking water. In this method of treatment, radium is exchanged for sodium or potassium. When the softener is cleaned, the radium is flushed away with the wastewater into a disposal site such as a leachfield or municipal sewer.

Another type of treatment called reverse osmosis has also been shown to remove most radium from drinking water. In this process, water is forced under pressure through a membrane leaving the radium behind. The radium is then flushed away. The process is relatively slow and may be more suitable for a household rather than a public water system.

  • Uranium- The Vermont DEC Water Supply Rule (2010) established maximum contaminant level for uranium in public drinking water at 20 ug/L. The Vermont Dept. of Health considers ug/l to be equivalent to pci/l. Anion exchange is the treatment of choice for uranium and is similar to water softening except that in this case uranium is removed and exchanged for chloride. Reverse osmosis also removes uranium. Public systems have additional treatment options not available to homeowners such as lime softening (to reduce radium and uranium) and coagulation and filtration (to reduce uranium).

  • Radon- If radon is present in your drinking water, test the air in your home as well. Consider treatment for your well water if the radon from the water is causing the level of radon in the air in your home to rise above the recommended indoor air action level of 4 pCi/L. It generally takes 10,000 pCi/L in water to increase the radon level in air by 1.0 pCi/L.

Aeration removes radon from water. In this treatment method, large volumes of air are blown through the water or the water is sprayed so that it is exposed to the air. In this way, the radon gas leaves the water and enters the air. The air is vented outside, and the treated water is repressurized and piped to faucets.


Public Water System Regulations and Testing Requirements; Wastewater Management Issues

Department of Environmental Conservation
Drinking Water and Groundwater Protection Division, Drinking Water Systems

Private Drinking Water: Health Concerns, Technical Assistance and Testing Guidance, Home Water Treatment

Department of Health
Health Protection Division
Environmental Health Unit

Laboratory Testing Services: Water Testing; To Order Test Kits

Public Health Laboratory
195 Colchester Avenue
Burlington, Vermont, 05402

Compilation and Assessment of Geophysical and Geological Radioactivity Data in Vermont


Generalized Geologic 
	Map of Vermont - 1970 - click for larger map image

VT DEC Geology and Mineral Resources Division 1 National Life Drive, Davis 2  Montpelier, VT  05620-3920 
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