Radon is a naturally occurring radioactive gas that is released when radium undergoes radioactive decay. The gas is linked to lung cancer, according to the E.O. Lawrence Berkeley National Laboratory at Columbia University in New York. Radon gas is found in all areas of the U.S. The Environmental Protection Agency recommends that all homes be tested for elevated levels of the gas.
Geology
High radon levels can occur as a natural process related to geology and rock decay. The Radon Project of Lawrence Berkeley National Laboratory and the Columbia University Department of Statistics list key geographic areas with naturally high levels of radon gas. The upper Midwest and northern plains states have higher levels of naturally occurring radon, but portions of southeast Pennsylvania, southwest Minnesota, much of Iowa and a pocket of land on the extreme eastern part of Washington state have the largest deposits of rock that cause the high gas levels. The Radon Project labels these high-radon "living area concentration" regions.
Use of Radon-Embedded Materials
The use of radon-embedded materials is related to high radon levels in homes. The Marble Institute of America has identified granite countertops and bathroom shower enclosures as containing radon. The Environmental Protection Agency notes that the levels of radon vary greatly between granite samples, and that "some types of granite may emit gamma radiation above typical background levels." In enclosed areas of the home with insufficient ventilation, the EPA states, levels may reach "higher than expected levels." A case-by-case analysis of the danger must be done to evaluate specific radon levels in homes with granite countertops and bathroom installations.
Trapped Gases
Home and commercial construction techniques frequently cause increased levels of radon gas. The colorless, odorless gas typically disperses into the environment without effect. Construction techniques often trap radon under a concrete foundation or basement. When cracks in the foundation occur, gases are released into the building or basement. This causes higher levels than would normally be found in that particular environment, according to the Utah Geological Survey. Radon barriers include the installation of additional concrete walls to halt gas seepage, and use of interior fans to divert the gases to the outside of the building.
Radon Water
Ground water transported through a public water system, or home water taken from a private well on the property that is contaminated with radon, both pose risks for high radon levels. Water wells in an area with large amounts of decaying uranium deposits create high levels of radon in the water. Water can effectively be filtered to remove radon to acceptable levels, but an abatement professional is required to ensure that the proper procedure is selected. The contractor also has the equipment to take an accurate radon reading of the water.
References
- Environmental Protection Agency: A Citizen's Guide to Radon
- Environmental Protection Agency: Radon
- Environmental Protection Agency: Radon: EPA Map of Radon Zones
- E.O. Lawrence Berkeley National Laboratory: High-Radon Project Home Page
- Columbia University Department of Statistics and Lawrence Berkeley National Laboratory: Radon Project
