Radon, formed by the natural radioactive decay of uranium, is the second leading cause of lung cancer.

 WHAT IS RADON

Radon is a radioactive, colorless, odorless, tasteless gas produced by the natural breakdown of uranium in soil and rocks. Decay of radon, which has a half-life of 3.8 days, results in the daughter products polonium, bismuth, astatine, and lead. When inhaled over a long period of time, these solid radioactive daughter products can cause lung-cancer. Between 2,000 and 3,000 lung cancer deaths are attributed to radon each year in the United States.

 

Radon can move through cracks in rocks and through pore spaces in soils.

(Source U.S. Geological Survey)
Because radon is a gas, it can migrate through rocks and soils, escaping into fractures and openings in rocks and into ground water. Radon moves more readily through permeable soils, such as sand and gravel, and through fractures in rocks. Radon moves more slowly in water than in air; therefore, moist soils retard its movement more effectively than dry soils. Radon moving through soil near the earth's surface usually escapes into the atmosphere. Radon gas may seep into our homes through construction joints, cracks in the foundation, or the water supply. Even if the soil air contains only moderate levels of radon, concentrations inside houses may be high. Thr U.S. Environmental Protection Agency's action level (the level at which steps should be taken to reduce radon) is 4 picocuries per liter of air (pCi/L). About 1 out of every 15 houses in the U.S. has radon levels exceeding the recommended action level.

 

(Source U.S. Geological Survey)

 EVALUATING RADON POTENTIAL
By evaluating the geology in an area, scientists can evaluate the radon potential of the rocks and soils at housing sites or other areas of interest. The factors listed below can increase the probability that an area will have above-average levels of radon.

1. Uranium-rich rocks underlie the area.

2. The site is located on a hill or slope.

3. Soils are well drained or dry most of the time.

4. Soils form deep cracks during dry time of the year.

5. Highly permeable soils are present.

6. The soils are thin and bedrock is close to the surface.

7. Underlying rocks are fractured.

8. The underlying rock contains limestone caverns.

9. High levels of indoor radon have been reported in the county or neighborhood.
 

(Source U.S. Geological Survey)

 OCCURRENCE OF RADON

Levels of radon vary from place to place and even from house to house within a given area. The higher the uranium content of the rocks that underlie an area, the greater the likelihood that houses in the area will contain elevated levels of radon. The only way to know if you have a radon problem is to test. It's quick, easy, and inexpensive.

 

ALABAMA RADON POTENTIAL MAP

Radioactivity maps indicate the uranium levels of surface materials. These maps can be used to show the potential for radon occurrence in different areas. The map below shows the potential for radon occurrence in Alabama.

 

(Source U.S. Geological Survey)

 TESTING FOR RADON

There are many kinds of inexpensive, do-it-yourself radon test kits available through the mail and in hardware stores and other retail outlets. Be sure to buy a kit that is approved by the EPA. Short-term tests may take as little as 2 days and are generally performed in the lowest level of the home.

 SOURCES OF RADON INFORMATION
Alabama Department of Public Health

Division of Radiation Control

1-800-582-1866

 

U.S. Environmental Protection Agency Region 4

(404)347-3907

http://www.epa.gov/iaq/radon

 

National Radon Information Hotline

1-800-SOS-RADON

 

U.S. Geological Survey

http://energy.cr.usgs.gov/radon/radonhome.html

 

American Lung Association

http://www.lungusa.org/

 

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