Radon testing of soils This information should be included in soil survey reports
decay, they release a burst of energy in the form of positively charged alpha particles consisting of a nucleus of two protons and two neutrons. Because of their large size, alpha particles have a short range in air (< 10 cm) and little penetrating power, but these high-energy particles can damage lung tissue and increase the risk of lung cancer. Estimates of lung cancer risk from accumulated low-level exposure to radon have been extrapolated from known highdose responses from epidemiological studies on underground
miners. Based on the average level of radon in US. homes (1.5 pCi/L), the increased chance of contracting lung cancer from indoor radon is about one in 250 and accounts for 10,CGU lung cancer deaths per year (2). The concentration of indoor radon varies widely (over 4 orders of magnitude), even among adjacent homes. Of the 80 million single-family homes in the United States, 1 million have been estimated to have greater than 8 pCi/L or 300 Bq/m’ of air. One picocurie is approximately equal to the decay of
By Michael Boyle Radon is the second leading cause of lung cancer. Radon monitoring of all homes was urged by U.S. Surgeon General Koop in a health advisory issued in September. Information on radon levels could be included in soil survey reports to help identify the health risks associated with current and fnture dwellings. Radon is a naturally occurring radioactive gas that is produced through the normal decay of uranium and thorium found in rocks and soil. Radon (222Rn) produced from uranium (238U) is the isotope of environmental concern. This noble gas is almost chemically inert, and an inhaled radon atom is very likely to be exhaled before it decays into other radioactive elements called radon daughters (Figure 1) (I).Radon daughters are initially, positively charged solids that rapidly adsorb to surfaces such as airborne dust particles; the average distance a free radon daughter travels before it becomes adsorbed is approximately 6 cm. If the contaminated dust is inhaled, these particles can adhere to lung surfaces. As two of these short-lived radon daughters @olonium 218 and polonium 214) W1~936WWC922-1397$01.~0Q 1988 American Chemical Saciely
Envimn.Sci.Tschnol..MI.22. No. 12.1988 1397
