Radon in mines

The first surveys of radon in US (Colorado) uranium mines were made in 1952, when the raised incidence of lung cancer in miners first became apparent (United States Public Health Service, 1957). The level was highly variable, with medians for each mine varying from 7 x 102 to 3 x 105 Bq m-3. The median of the medians was 4 x 104 Bq m-3,1000 times higher than the median concentration in houses (Table 1.4). Subsequently, ventilation was improved and other measures were taken, for example disused parts of mines were sealed off. The median of medians was reduced to 1 x 104 Bq m-3 in 1956 and to 4 x 103 Bq m-3 in 1966. In a survey of six mines in New Mexico in 1970, George Hinchliffe (1972) found a median radon concentration of 7 x 103 Bq m-3. 

In 1955, the International Commission on Radiological Protection set a maximum permissible occupational concentration of 3.7 x 103 Bq m-3 (10-10 Ci l-1), for continuous exposure, equivalent to 1.1 x 104 Bq m-3 (3 x 10-10 pCi P1) for a 40-h working week. Subsequently, when it was realised that the critical dose to the lung was from inhalation of decay products, not radon itself, the permissible concentration was defined in terms of the concentration of decay products. The current recommended limit (ICRP, 1986) for a working period of 2000 h per year is 1.5 x 103 Bq m 3 equilibrium equivalent radon concentration (a term defined in Section 1.8 below). 

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National Research Council, Comparative Dosimetry of Radon in Mines and Homes, Panel on Dosimetric Assumption Affecting the Applications of Radon Risk Estimates, Board on Radiation Effects Research, Commission on Life Sciences, National Academy Press, Washington, D.C., 1991. 

Jakupi B, Krstic G, Tonic M, Ilic R (1997) Radon in mines and dwellings in Kosovo and Metohia. Radiat Meas 28 691-694... 

Epidemiological studies on miners indicate an increased incidence of lung cancer from exposure to radon in mines with high radon concentrations (Roscoe et al., 1989). In Ontario uranium mines, miners mortality for lung cancer is significantly higher than expected for the population (observed = 152, expected = 67). The mortality from lung cancer is clearly associated with the exposure of workers to the descendants of shortlived radon (Kusiak et al., 1993). 

NAS. Comparative Dosimetry of Radon in Mines and Homes. Washington, DC National Academy Press, 1991. 

Harley, N.H., Radon and Lung Cancer in Mines and Homes, New England Journal of Medicine, 310 1525-1526 (1984). 

Kusnetz H.L., 1956, Radon Daughters in Mine Atmospheres, a Field Method for Determing Concentrations, Ind.Hyg.Quart., 17, 85-88. 

Pogorski, S. and C.R. Phillips, The Transient Response of Radon and Thoron Chambers, Proc. Int. Conf. Occupational Radiation Safety in Mining, (H. Stocker, ed), vol. 2, 394, Can. Nucl. Assoc. (1985). 

Jonassen, N., Electrical Properties of Radon Daughters in Proc. Int. Conf. Occupational Radiation Safety in Mining,... 

The lung cancer risk from radon daughter exposure is known only for occupationally exposed males. In order to determine the risk in environmental situations it is necessary to determine whether the bronchial alpha dose, which confers the risk, is similar to that in mines. 

Edling,C., Lung Cancer and Radon Daughter Exposure in Mines and Dwellings study no. V. Linkoping University, Medical Dissertation No. 157, Dept, of Occup. Med., Linkoping, Sweden (1983). 

Abelson, P.H. Mineral Dusts and Radon in Uranium Mines, Science. 777... 

Nielson KK, Rogers VC. 1981. Health effect coefficients for radium and radon released in the mining and milling of uranium. In Gomez M, ed. Radiation Hazards in Mining, 760-763. 

Austin, S.R., 1975. A laboratory study of radon emanation from domestic uranium ores. Radon in uranium mining, IAEA Vienna, PL-565/8, pp. 151-160. 

Barnes, I., Platfker, G., White, D. and Armstrong, A.K., 1980. Potential natural gas in the Gulf of Alaska indicated by calcite depleted in carbon-13. In W.L. Coonrad (cd.). The United States Geological Survey in Alaska - accomplishments during 1980. US Gcol. Survey, Circular 844, pp. 143-146.Barretto, P.M.C., 1975. Radon-222 emanation characteristics of rocks and minerals. Reprint from "Radon in Uranium Mining", IAEA, Vienna, pp. 129-150. 

Smoking and exposure to radon have a synergistic multiplicative effect on lung cancer incidence. I126 This effect has been observed in instances of household radon/smoking combinations 127 as well as jn industrial dual exposures, most notably in mining populations. 128 No well-understood mechanism exists at this time to account for this effect. 

ERA recommends that all homes should be monitored for radon. If testing shows levels less than 4 picocuries radon per liter of air, then no action is necessary. For levels above this, follow-up measurements should be taken. If follow-up levels are 20 picocuries radon per liter of air or higher, the home owner should consider some type of procedure to decrease indoor radon levels. The Mine Safety and Health Administration (MSHA) uses a standard of 4 Working Level Months (WLM) per year for people who work in mines. (Working Level Months combine the amount with length of exposure.) You will find more information on guidelines and standards in Chapter 7. 

Other airborne irritants, as well as ore dust and diesel exhaust, may act synergistically with radon and radon daughters to increase the incidence of adverse health effects. Epidemiological studies report the presence of other airborne irritants in mining environments, including arsenic, hexavalent chromium, nickel, cobalt (Sevc et al. 1984), serpentine (Radford and Renard 1984), iron ore dust (Damber and Larsson 1982 Ediing and Axelson 1983 Radford and Renard 1984), and diesel exhaust (Damber and Larsson 1982 Sevc et al. 1984). 

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