Radon

Type: Gas
Periodic Element: (Rn)
RDA: If testing shows levels less than 4 picocuries radon per liter of air (150 Bq/m3), then no action is necessary.
Importance- To Body:
Contaminant
Distribution- In Body:
As radon itself decays, it produces decay products, which are other radioactive elements called radon daughters (also known as radon progeny). Unlike the gaseous radon itself, radon daughters are solids and stick to surfaces, such as dust particles in the air. If such contaminated dust is inhaled, these particles can also cause lung cancer.
Excess Effects:
Epidemiological studies have shown a clear link between breathing high concentrations of radon and incidence of lung cancer. Radon is a contaminant that affects indoor air quality worldwide.
Deficiency Effects:
None listed
Sources:
Sources Environmental/Geographic:
Radon is produced by the radioactive decay of radium-226, which is found in uranium ores, phosphate rock, shales, igneous and metamorphic rocks such as granite, gneiss, and schist, and to a lesser degree, in common rocks such as limestone. Some of the highest radon hazard in the United States is found in Iowa and in the Appalachian Mountain areas in southeastern Pennsylvania. Some of the highest readings ever have been recorded in the Irish town of Mallow, County Cork, prompting local fears regarding lung cancer.
Most countries have adopted a radon concentration of 200–400 Bq/m3 for indoor air as an Action or Reference Level. Very high radon concentrations (>1000 Bq/m3) have been found in houses built on soils with a high uranium content and/or high permeability of the ground. If levels are 20 picocuries radon per liter of air (800 Bq/m3) or higher, the home owner should consider some type of procedure to decrease indoor radon levels.
Supplemental information: