Variation of 222Rn Activity Concentration in Soil Gas at a Site in Sapporo, Japan

Fujiyoshi, Ryoko; Kinoshita, Moriyoshi; Sawamura, Sadashi

doi:10.1007/s10653-005-7569-4

Cited by 13 publications

(13 citation statements)

References 19 publications

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“…6 In the observation site in Sapporo soil sampling was carried out in different seasons to investigate seasonal variation of the soil properties including environmental radionuclides ( 226 Ra, 137 Cs and 210 Pb) other than 40 K. Radon ( 222 Rn) and CO 2 (and its carbon isotopes,  13 C and  14 C) have also been monitored in this site since 2002. 5,10,11,17 It is interested to note in Table 1 that the amount of soil organic matter varied in winter-high and summer-low under a deciduous stand in Sapporo.…”

Section: Resultsmentioning

confidence: 99%

Depth profiles of potassium and its isotope ratio (40K/K) in several forest soils

Fujiyoshi

Satake

Sumiyoshi

2009

J Radioanal Nucl Chem

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Depth profiles potassium and its isotope ratio ( 40 K/K) were investigated in several forest soils from different geological and climatic backgrounds. The ratio was found not to be constant (0.0117 %) but varied appreciably from 0.0085 to 0.0167 % among different soils.Possible factors affecting variability of 40 K/K values were considered by a multivariate factor analysis which suggested that aqueous parameters like humidity and pH might be a controlling factor in the surface soils. The amount (and probably chemical forms) of iron oxide may be another one influencing 40 K/K values in mineral components at deeper portions.

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Section: Resultsmentioning

confidence: 99%

Depth profiles of potassium and its isotope ratio (40K/K) in several forest soils

Fujiyoshi

Satake

Sumiyoshi

2009

J Radioanal Nucl Chem

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“…kg -1 ) was much smaller than those observed in soils under deciduous and coniferous temperate stands in Germany, Czech Republic as well as in Japan (Table 2). 4,5,7 Cesium-137 is a typical man-made radionuclide with a half life of 30.17 years. A great many studies have already been published on the behavior of this nuclide in various regions in the world.…”

Section: Photo 1 View Of a Ceiba Tree (Ceiba Trichistandra)mentioning

confidence: 99%

“…The level is more than 5 times higher than that obtained in Sapporo, Japan (Table 2). 5 A summary was published on the environment in the Alto Mayo Protected Forest region. 9 According to this report, the wind primarily originates from the east and from the north during the first three and last three months of the year, respectively.…”

Section: Site 2 (Alto Mayo)mentioning

confidence: 99%

“…They showed applicability of these nuclides of different origin and of chemical properties as tracers for tracking natural and anthropogenic transition under various temperate stands in Germany and Czech Republic as well as on the campus of Hokkaido University in Sapporo, Japan. [4][5][6][7] The purpose of the this study is to elucidate natural and anthropogenic consequences on tropical forest soils in northern Peru where little intervention by men has been encountered so far using several environmental radionuclides ( 40 K, 137 Cs, 210 Pb and 226 Ra) as natural tracers. Figure 1 shows the location map of investigation sites (El Angolo and Alto Mayo) in Northern Peru.…”

Section: Introductionmentioning

confidence: 99%

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Natural and anthropogenic consequences of tropical forest soils in Northern Peru using environmental radionuclides as radiotracers

Fujiyoshi

Satake

Satō

et al. 2009

J Radioanal Nucl Chem

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Environmental radionuclides ( 40 K, 137 Cs, 210 Pb, 226 Ra) were determined in soils under semi-arid stands, a transition area from thorn to deciduous forest in El Angolo, and heath stands in the Alto Mayo in Northern Peru in order to elucidate their activity level in soil, and to trace underground environment in remote areas of little anthropogenic intervention. Anthropogenic 137 Cs was only found in the uppermost portion of the soils in small amount, whereas the 210 Pb activity was exceptionally high at the soil surfaces in a tropical stand of Alto Mayo. The results suggest a fallout nuclide, 210 Pb, having been transported from local source(s) not to be specified yet.

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“…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 (Yakovleva 2005;Perrier and Girault 2013). Monitoring soil radon for several years since 2004 gave the results that a major factor affecting soil 222 Rn concentration was soil temperature under high atmospheric pressure region in three seasons except for winter on a campus forest site of the Hokkaido University, Japan (Fujiyoshi et al 2005(Fujiyoshi et al , 2006(Fujiyoshi et al , 2010. In contrast, lower 222 Rn concentration with small variability appeared in soil under persisting snow in winter months from December to March.…”

Section: Introductionmentioning

confidence: 99%

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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Variation of 222Rn Activity Concentration in Soil Gas at a Site in Sapporo, Japan

Cited by 13 publications

References 19 publications

Depth profiles of potassium and its isotope ratio (40K/K) in several forest soils

Depth profiles of potassium and its isotope ratio (40K/K) in several forest soils

Natural and anthropogenic consequences of tropical forest soils in Northern Peru using environmental radionuclides as radiotracers

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

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