A comprehensive review of radon emanation measurements for mineral, rock, soil, mill tailing and fly ash

Sakoda, Akihiro; Ishimori, Yuu; Yamaoka, Kunihiro

doi:10.1016/j.apradiso.2011.06.009

Cited by 212 publications

(89 citation statements)

References 55 publications

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“…This mobility can induce a substantial decrease (up to about one half) of dose rate, because of the loss of the Radon daughters by the system. Loss of Rn in «Fe laterite» has been reported as low as 3% by Sakoda et al (2011), but this can probably be much higher as it is expected to depend on the evolution of porosity during the lifetime of the iron duricrust. Consequently, in absence of detailed information about the evolution of porosity, two extreme scenarii of 100% Rn loss (considered as a worst case for an open system) and 0% Rn loss (closed system) were taken into account to calculate dose rates and bracket the possible ages of kaolinite trapped in the duricrust.…”

Section: Dose Rate Determinationmentioning

confidence: 99%

Combined dating of goethites and kaolinites from ferruginous duricrusts. Deciphering the Late Neogene erosion history of Central Amazonia

et al. 2018

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This study focuses on the dating of millimetric pisoliths from ferruginous duricrusts located in central Amazonia (Brazil), by coupling detailed mineralogy and two relevant dating methods: (i) (U-Th)/He analysis of goethites by mass spectrometry; (ii) analysis of radiation-induced defects of kaolinites embedded in duricrusts by electron paramagnetic resonance spectroscopy (EPR). Three samples collected at different elevations in the landscape were selected. The goethite corrected ages range from 1.1-15.2 Ma and consistently increase with elevation. EPR was performed on kaolinites after several cycles of a deferration procedure. Considering extreme geochemical scenarii, the ages of kaolinites are 1.7-7.1 Ma for a closed system and 4.0-16.7 Ma for an open system with 100% Rn loss. Ages of goethites and kaolinites are close, in the limit of the uncertainty of the methods. They show important periods of duricrust formation at Middle Miocene and at Late Miocene/Pliocene. Data allow the estimation of lowering rates between 3 and 8 m/Ma, in agreement with independent data available in the literature for the central Amazonia region or even for erosion of other cratons in the world. The two dating methods can be compared on common duricrust samples. By revealing single or multi-step weathering/erosion episodes related to relictual paleosurfaces, they also bring promising contributions to an advanced knowledge of ancient and complex lateritic geosystems.

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Section: Dose Rate Determinationmentioning

confidence: 99%

Combined dating of goethites and kaolinites from ferruginous duricrusts. Deciphering the Late Neogene erosion history of Central Amazonia

et al. 2018

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“…The rest (fraction 1 -f ) remain trapped in the solid mineral grains. A comprehensive review on emanation measurements is provided by Sakoda et al (33) . One of the key findings of emanation studies is the fact that in the range of 0-10 % of the volumetric water content in soil pores, the emanation factor increases roughly by a factor of two (21, 33 -37) .…”

Section: Emanationmentioning

confidence: 99%

Effect of Soil Moisture on Seasonal Variation in Indoor Radon Concentration: Modelling and Measurements in 326 Finnish Houses

Arvela

Holmgren

Hänninen

2015

Radiat Prot Dosimetry

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The effect of soil moisture on seasonal variation in soil air and indoor radon is studied. A brief review of the theory of the effect of soil moisture on soil air radon has been presented. The theoretical estimates, together with soil moisture measurements over a period of 10 y, indicate that variation in soil moisture evidently is an important factor affecting the seasonal variation in soil air radon concentration. Partitioning of radon gas between the water and air fractions of soil pores is the main factor increasing soil air radon concentration. On two example test sites, the relative standard deviation of the calculated monthly average soil air radon concentration was 17 and 26 %. Increased soil moisture in autumn and spring, after the snowmelt, increases soil gas radon concentrations by 10-20 %. In February and March, the soil gas radon concentration is in its minimum. Soil temperature is also an important factor. High soil temperature in summer increased the calculated soil gas radon concentration by 14 %, compared with winter values. The monthly indoor radon measurements over period of 1 y in 326 Finnish houses are presented and compared with the modelling results. The model takes into account radon entry, climate and air exchange. The measured radon concentrations in autumn and spring were higher than expected and it can be explained by the seasonal variation in the soil moisture. The variation in soil moisture is a potential factor affecting markedly to the high year-to-year variation in the annual or seasonal average radon concentrations, observed in many radon studies.

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“…Mean D e value thus obtained as 5×10 −6 m 2 s −1 is reasonable by considering homogeneous and well-drained soil in our test site (Nazaroff 1992;Sakoda et al 2011). Diffusion-controlled 222 Rn flux in soil air was therefore estimated to be about 1×10 −1 Bq m −2 s −1 during observation period from August to September in 2013.…”

Section: Gamma Spectrometrymentioning

confidence: 83%

Soil radon (222Rn) monitoring in a forest site in Fukushima, Japan

et al. 2014

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Soil radon ( 222 Rn) has been monitored since August 2013 at three different soil depths on a campus forest of Fukushima University in Japan where a large amount of fallout nuclides were released by the accident of Fukushima Daiichi Nuclear Power Plant in March 2011. The primary purpose of this study is to evaluate 222 Rn activity level, variability and factors controlling 222 Rn concentration in soil air using data obtained from August to December 2013. Time series of 222 Rn activity concentration showed depth-dependent variability with an equilibrium value ( 222 Rn eq ) during this observation period; 7.5, 14 and 23 kBq m -3 at 0.3, 0.6 and 1.0 m in depth, respectively. Two typhoons passing over the site had a great influence on soil radon level, which was practically used for evaluating effective diffusion coefficient of 222 Rn there. Transport mechanism of 222 Rn in soil air was considered to be diffusion-controlled with data sets on changing 222 Rn concentration with time in selected cases that showed decreasing (or increasing) 222 Rn concentration with time at every depth. Important factors affecting soil 222 Rn variability are meteorological parameters, low pressure front passing over the site, and subsequent precipitation. Time-lags of decreasing 222 Rn concentration at different depths after rain indicate a certain relationship of 222 Rn level with moving water (and water vapor) in soil. The findings obtained in this study are important to evaluate fate of fallout nuclides (radiocesium) in contaminated forest sites using soil radon as a tracer of moving soil air. IntroductionRadon ( 222 Rn) in the environment has been extensively studied to evaluate dose levels due to inhaling the radioactive gas into the body, to estimate its flux from the ground surface to the atmosphere (exhalation) as a tracer of air movement in the lower atmosphere, and to predict seismic activity in tectonically active areas (Dorr et al. 1983;Zahorowski et al. 2004;Vaupotič et al 2010). Another important and basic aspect exists in the study of 222 Rn in soil air to elucidate mechanisms of its migration in soil and transportation to the ground surface (Nazaroff 1992;Neznal and Neznal 2005;Fujiyoshi et al. 2010Fujiyoshi et al. , 2013. Soil radon monitoring has shown that 222 Rn activity concentration varies to a great extent depending on geological, meteorological and hydrological factors, and that its migration through the soil and rock is controlled not only by diffusion but convection It is widely recognized that both liquid and gaseous water movements are fundamental factors controlling many processes in soil. Soil water dynamics are strongly linked to temperature variations and then biological activities. These processes, complicated due to interrelations among controlling factors, have not been clarified thoroughly (Wells et al. 2007;Bittelli et al. 2008). Understanding radon transportation in soil is useful for evaluating soil air movement in the surface soil layers, because radon is chemically inert and radioactive...

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A comprehensive review of radon emanation measurements for mineral, rock, soil, mill tailing and fly ash

Cited by 212 publications

References 55 publications

Combined dating of goethites and kaolinites from ferruginous duricrusts. Deciphering the Late Neogene erosion history of Central Amazonia

Combined dating of goethites and kaolinites from ferruginous duricrusts. Deciphering the Late Neogene erosion history of Central Amazonia

Effect of Soil Moisture on Seasonal Variation in Indoor Radon Concentration: Modelling and Measurements in 326 Finnish Houses

Soil radon (222Rn) monitoring in a forest site in Fukushima, Japan

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