Radon transport from soil to air

Reviews of Geophysics - Tập 30 Số 2 - Trang 137-160 - 1992
William W. Nazaroff

Tóm tắt

Radon generated within the upper few meters of the Earth's crust by the radioactive decay of radium can migrate during its brief lifetime from soil into the atmosphere. This phenomenon leads to a human health concern as inhalation of the short‐lived decay products of radon causes irradiation of cells lining the respiratory tract. This paper reviews the factors that control the rate at which two radon isotopes, 222Rn and 220Rn, enter outdoor and indoor air from soil. The radium content of surface soils in the United States is usually in the range 10–100 Bq kg−1. The emanation coefficient, which refers to the fraction of radon generated in a material that enters the pore fluids, varies over a wide range with a typical value being 0.2. Radon in soil pores may be partitioned among three states: in the pore air, dissolved in the pore water, and sorbed to the soil grains. Except in the immediate vicinity of buildings, radon migrates through soil pores principally by molecular diffusion. Average reported flux densities from undisturbed soil into the atmosphere are 0.015–0.048 Bq m−2 s−1 for 222Rn and 1.6–1.7 Bq m−2 s−1 for 220Rn. Soil is the dominant source of radon in most buildings. Advective flow of soil gas across substructure penetrations is a key element in the transport process. The advective flow is driven by the weather (wind and indoor‐outdoor temperature differences) and by the operation of building systems, such as heating and air conditioning equipment. A typical radon entry rate into a single‐family dwelling of 10–15 kBq h−1 can be accounted for by weather‐induced pressure‐driven flow through moderately to highly permeable soils. The extent to which diffusion through soil pores contributes to radon entry into buildings is not known, but in buildings with elevated concentrations, diffusion is believed to be less important than advection.

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Tài liệu tham khảo

American Society of Heating, Refrigerating, and Air‐Conditioning Engineers, 1985, ASHRAE Handbook—1985 Fundamentals

Andrews J. N., 1972, Mechanism of radon release in rock matrices and entry into groundwaters, Trans. Inst. Min. Metall., Sect. B, 81, 198

10.1029/GL017i006p00825

Austin S. R. R. F.Droullard Radon emanation from domestic uranium ores determined by modifications of the closed‐can gamma‐only assay methodRep. RI 8264Denver Min. Res. Cent. Denver Colo. 1977.

Barretto P. M. C. Emanation characteristics of terrestrial and lunar materials and the radon‐222 loss effect on the uraniumlead system discordance Ph.D. dissertation Rice Univ. Houston Tex. 1973.

Bates R. C., 1981, Radiation Hazards in Mining: Control, Measurement and Medical Aspects, 149

Bear J., 1972, Dynamics of Fluids in Porous Media, 126

10.1093/oxfordjournals.rpd.a082966

Bowles J. E., 1979, Physical and Geotechnical Properties of Soils, 213

10.1080/14786441208637183

Browne E., 1986, Table of Radioactive Isotopes

10.1080/00022470.1983.10465550

10.1029/JC079i033p05025

Committee on the Biological Effects of Ionizing Radiation, 1988, Health Risks of Radon and Other Internally Deposited Alpha‐Emitters

10.1029/JB074i017p04199

10.1016/0048-9697(85)90236-0

DSMA Atcon A computer study of soil gas movement into buildingsRep. 1389/1333Dep. of Health and Welfare Ottawa Ont. 1985.

10.1016/0378-7788(83)90005-1

10.1097/00010694-195504000-00002

Garbesi K. Experiments and modeling of the soil‐gas transport of volatile organic compounds into a residential basementRep. LBL‐25519 Rev.Lawrence Berkeley Lab. Berkeley Calif. 1988.

10.1109/23.106733

George A. C., 1980, Proceedings of the Natural Radiation Environment III, U.S. Dep. of Comm. Rep. Conf‐780422, 1272

10.1029/GL017i006p00841

10.1016/0140-6736(90)91071-H

10.1098/rspa.1939.0016

Hopke P. K. The initial atmospheric behavior of radon decay productsTech. Rep. DOE/ER‐0375U.S. Dep. of Energy Washington D. C. 1988.

Houseworth J. E. Longitudinal dispersion in nonuniform isotropic porous media Ph.D. dissertation Calif. Inst. of Technol. Pasadena 1984.

10.1097/00004032-198308000-00008

Israelsson S., 1980, Proceedings of the Natural Radiation Environment III, U.S. Dep. of Comm. Rep. Conf‐780422, 210

James A. C., 1988, Radon and Its Decay Products in Indoor Air, 259

10.1021/es00020a013

Kalin M., 1981, Radiation Hazards in Mining: Control, Measurement and Medical Aspects, 707

Knutson E. O., 1988, Radon and Its Decay Products in Indoor Air, 161

Kraner H. W., 1964, Natural Radiation Environment, 191

10.1016/0016-7037(88)90327-4

10.1034/j.1600-0889.1990.00007.x

Kunz C. C. A.Laymon C.Parker Gravelly soils and indoor radonEPA 1988 Symposium on Radon and Radon Reduction TechnologyEnviron. Protect. Agency Denver Colo.Oct. 17–21 1988.

10.1029/JD089iD05p07291

10.1021/es00079a007

10.1097/00004032-198909000-00008

10.1097/00004032-198907000-00015

10.1111/j.1365-2389.1958.tb01892.x

10.2136/sssaj1982.03615995004600060024x

10.1029/JB079i023p03357

10.1097/00004032-198805000-00001

10.1097/00004032-198309000-00006

10.1029/GL017i006p00821

National Council on Radiation Protection and Measurements Measurement of radon and radon daughters in airRep. 97 174 Bethesda Md. 1988.

10.1093/oxfordjournals.rpd.a080269

10.1097/00004032-198812000-00018

Nazaroff W. W., 1988, Radon and Its Decay Products in Indoor Air

10.1021/es00181a010

10.1021/es00076a600

10.1016/0004-6981(85)90134-9

10.1097/00004032-198703000-00002

10.1021/es00159a006

Nazaroff W. W., 1988, Radon and Its Decay Products in Indoor Air, 57

Nazaroff W. W. B. A.Moed R. G.Sextro K. L.Revzan A. V.Nero Factors influencing soil as a source of indoor radon: Framework for assessing radon source potentialRep. LBL‐20645Lawrence Berkeley Lab. Berkeley Calif. 1989.

10.1063/1.881213

10.1093/oxfordjournals.rpd.a082958

10.1126/science.3775373

Nero A. V. A. J.Gadgil W. W.Nazaroff K. L.Revzan Indoor radon and decay products: Concentrations causes and control strategiesTech. Rep. DOE/ER‐0480P 138U.S. Dep. of Energy Washington D. C. 1990.

Powers R. P., 1980, Proceedings of the Natural Radiation Environment III, U.S. Dep. of Comm. Rep. Conf‐780422, 640

Rama, 1990, Micro‐crystallinity in radioactive materials, Int. J. Radiat. Appli, Instrum. Part E, Nucl. Geophys., 4, 475

Revzan K. L. Supplemental information on the National Aerial Radiometric Reconnaissance (NARR) DatabaseRep. LBID‐1453Lawrence Berkeley Lab. Berkeley Calif. 1988.

10.1093/oxfordjournals.rpd.a080266

10.1021/ie50726a005

10.1097/00004032-199106000-00006

10.1097/00004032-199108000-00006

Rogers V. C. K. K.Nielson G. B.Merrell D. R.Kalkwarf The effects of advection on radon transport through earthen materialsRep. NUREG/CR‐3409 PNL‐4789 RAE‐18‐4U.S. Nucl. Regul. Comm. Washington D.C. 1983.

Rogers V. C. K. K.Nielson G. B.Merrell Radon generation adsorption absorption and transport in porous mediaRep. DOE/ER/60664‐1U.S. Dep. of Energy Washington D. C. 1989.

10.1016/0375-6742(90)90100-O

Rundo J., 1979, Observation of high concentrations of radon in certain houses, Health Phys., 36, 729

Sachs P., 1972, Wind Forces in Engineering

10.1093/jnci/81.10.745

Scheidegger A. E., 1974, The Physics of Flow Through Porous Media

10.1080/10473289.1990.10466704

10.1029/JD094iD15p18297

10.1029/JB087iB04p02969

10.1029/JD089iD05p07299

10.1029/JD094iD06p08567

Scott A. G., 1988, Radon and Its Decay Products in Indoor Air, 407

10.1021/bk-1987-0331.ch002

Silker W. B. andD. R.Kalkwarf Radon diffusion in candidate soils for covering uranium mill tailings Rep. PNLO‐4434 Pac. Northwest Lab. Richland Wash. (Also available as Rep. NUREG/CR‐2924 U.S. Nucl. Regul. Cowan. Washington D. C. 1983.)1983.

Stranden E., 1988, Radon and Its Decay Products in Indoor Air, 113

10.1093/oxfordjournals.rpd.a082962

10.1097/00004032-198201000-00003

Strong K. P., 1981, Radiation Hazards in Mining: Control, Measurement and Medical Aspects, 713

Tanner A. B., 1964, Natural Radiation Environment, 161

Tanner A. B., 1980, Proceedings of the Natural Radiation Environment III, U.S. Dep. of Comm. Rep. CONF‐780422, 5

Terzaghi K., 1967, Soil Mechanics in Engineering Practice

Thamer B. J. K. K.Nielson K.Felthauser The effects of moisture on radon emanation including the effects on diffusionRep. BuMines OFR 184‐82 PB83‐136358U.S. Dep. of Comm. Washington D. C. 1981.

10.4141/cjss80-055

Tuma J. J., 1973, Engineering Soil Mechanics, 102

Turk B. H. R. J.Prill W. J.Fisk D. T.Grimsrud B. A.Moed R. G.Sextro Radon and remedial action in Spokane River Valley homes vol. 1 Experimental design and data analysisRep. LBL‐23430Lawrence Berkeley Lab. Berkeley Calif. 1987.

10.1080/10473289.1991.10466873

U.S. Department of Agriculture group Soil Survey Manual Handb. 18 Soil Conservation Service Washington D. C. 1962.

10.1175/1520-0469(1957)014<0160:PSOHWS>2.0.CO;2

10.1029/GL017i006p00829

10.1126/science.183.4123.413

Wilkening M. H., 1972, Proceedings of the Natural Radiation Environment II, U.S. Dep. of Comm. Rep. Conf‐720805, 717

10.1029/GL017i006p00805

Wollenberg H. A. A. R.Smith Naturally occurring radioelements and terrestrial gamma‐ray exposure rates: An assessment based on recent geochemical dataRep. LBL‐18714Lawrence Berkeley Lab. Berkeley Calif. 1984.

10.1097/00004032-198308000-00010

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Reviews of Geophysics

Tập 30 Số 2

137-160

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