Radon mobility

One aspect of radon mobility, in relation to groundwater, is being studied by O.S. Zepecza (U.S. Geological Survey). He is determining the factors which control radionuclide transport and fate in groundwater in the Newark basin and southern coastal plains of New Jersey, and the mechanism of release of radionuclides to groundwater or retention in aquifer solids. 

Deals with issues that affect the quality of our air and protection from exposure to harmful radiation. OAR de >el-ops national programs, technical policies, and regulations for controlling air pollution and radiation exposure. Areas of concern to OAR include indoor and outdoor air quality, stationaiy and mobile sources of air pollution, radon, acid rain, stratospheric ozone depletion, radiation protection, and pollution prevention. 

There are a series of papers that focus on the behavior of the radon decay products and their interactions with the indoor atmosphere. Previous studies (Goldstein and Hopke, 1983) have elucidated the mechanisms of neutralization of the Po-218 ionic species in air. Wilkening (1987) reviews the physics of small ions in the air. It now appears that the initially formed polonium ion is rapidly neutralized, but can become associated with other ions present. Reports by Jonassen (1984) and Jonassen and McLaughlin (1985) suggest that only 5 to 10% of the decay products are associated with highly mobile ions and that much of the activity is on large particles that have a bipolar charge distribution. 

Kulju, L.M., K.D. Chu, and P.K. Hopke, The Development of a Mobility Analyzer for Studying the Neutralization and Particle Producing Phenomena Related to Radon Progeny, this volume (1987). 

The ratio of mobile radon to the total radon produced is referred to as the emanating fraction or emanation coefficient. The range of observed emanation coefficients is indicated in Table I. The effect of moisture on the emanation coefficient has been noted by several authors (Thamer fill al.. 1981 Strong and... 

Development of a Mobility Analyzer for Studying the Particle-Producing Phenomena Related to Radon Progeny... 

The determination of the activity size distribution of the ultrafine ions is of particular interest due to their influence on the movement and deposition of Po-218. These ultrafine ions are the result of radiolysis and their rate of formation is a function of radon concentration, the energy associated with the recoil path of Po-218, and the presence of H O vapor and trace gases such as S02 a joint series of experiments utilizing a mobility analyzer, the separate single screen method, and the stacked screen method were conducted to examine the activity size distribution of the ultrafine mode. 

These radon daughter ions have electrical mobilities in the same range as ordinary atmospheric ions and the ions can be divided into a number of groups where each group has a particular mobility (Nolan, 1916 McClelland and Nolan, 1926). Bricard et al. (1966) reports measurements for five distinct mobility groups with values in the range of 0.4-2.2 cm s v for small radioactive ions in air. 

This diffusion chamber was modified to provide a uniform flow from two channels at the entrance, one for the filtered room air and the other for the gas from the radon chamber. This modified mobility analyzer is schematically shown in Figure 2. The pressure heads are adjusted so that the gas velocities, v, are the same in both channels. An adjustable vertical electric field, E, is provided through the analyzer so that charged particles are drawn toward the detector located at x cm from the entrance. With the known distance, d, between the radon-laden gas channel and the detector implanted plate, the mobility can then be determined from... 

In order to examine the process of ultrafine particle formation, a joint series of experiments were conducted at the Denver Research Center of the U.S. Bureau of Mines. In the Denver radon chamber, the activity size distribution of the ultrafine mode was measured using the mobility analyzer designed by Chu and Hopke (1985), the separate single screen method (Holub and Knutson, 1987), and the stacked single screen method (Holub and Knutson, 1987) for various relative humidities and for various concentrations of SO. The results... 

Another concept relating to the decay products is that of the "unattached" fraction. Although it is now known that the decay product atoms are really attached rapidly to ultrafine particles (0.5 to 3 nm in diameter), there is a long history of an operationally defined quantity called the "unattached" fraction. These decay products have much higher mobilities in the air and can more effectively deposit in the respiratory system. Thus, for a long time the "unattached" fraction has been given extra importance in estimating the health effects of radon decay products. Typically most of the "unattached" activity is Po-218 and the value of unattached frac-... 

Mobility of Uranium and Radon associated with uranium roll front occurrences in the Horton Group of the Windsor area, Nova Scotia,... 

The rate and quantity of radon and uranium contributed to waters exposed to mineralized outcrops and the subsequent mobility of these elements in the present day environment has not been previously documented. This paper presents the results from leaching experiments carried out on uranium-enriched Horton Group sandstones in the Windsor area of Nova Scotia. Understanding of these processes is important both to environmental and exploration geochemistry. 

In the environment, thorium and its compounds do not degrade or mineralize like many organic compounds, but instead speciate into different chemical compounds and form radioactive decay products. Analytical methods for the quantification of radioactive decay products, such as radium, radon, polonium and lead are available. However, the decay products of thorium are rarely analyzed in environmental samples. Since radon-220 (thoron, a decay product of thorium-232) is a gas, determination of thoron decay products in some environmental samples may be simpler, and their concentrations may be used as an indirect measure of the parent compound in the environment if a secular equilibrium is reached between thorium-232 and all its decay products. There are few analytical methods that will allow quantification of the speciation products formed as a result of environmental interactions of thorium (e.g., formation of complex). A knowledge of the environmental transformation processes of thorium and the compounds formed as a result is important in the understanding of their transport in environmental media. For example, in aquatic media, formation of soluble complexes will increase thorium mobility, whereas formation of insoluble species will enhance its incorporation into the sediment and limit its mobility. 

Warner, Kenneth E., David Mendez, and Paul N. Courant. 1996. Toward a More Realistic Appraisal of the Lung Cancer Risk from Radon The Effects of Residential Mobility. American Journal of Public Health 86 1222-27. 

Jonassen, N. Hayes, E. (1972) Mobility distribution of radon-222 daughter small ions in laboratory air. Journal of Geophysical Research, 77, 5876-82. 

Ukraine s Chernobyl Nuclear Plant, wearing protective clothing, from International Mobile Radiological Laboratories, near Chernobyl, Ukraine, photograph. Reuters NewsMedia Inc./Corbis. Reproduced by permission p. 60 Radon test kit and carbon monoxide detector, photograph by Robert J. Huffman. 

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