Investigation of 220Rn emanation and exhalation from soil samples of Larsemann Hills region, Antarctica

In the present study, thoron exhalation flux density were measured in the soil samples collected around the Indian station namely Bharati (69° 24.41' S, 76° 11.72' E) and its nearby islands in the Larsemann hills region of Antarctica. Further, dependency of thoron mass emanation rate and emanation coefficient on the soil grain size was studied by segregating the soil samples into four different grain size groups: 50-100 μm, 100-200 μm, 200-500 μm and 500-1000 μm which showed that both of them follow a decreasing trend with increase in grain size. A comparison of measured mass emanation rate between different soil samples showed that it had a larger variation for the smaller grain size which eventually decreased as grain size increased while emanation coefficient was observed to be nearly constant for all the grain size groups. The variation in emanation coefficient with respect to mean grain size has been investigated and an empirical exponential model has been proposed for predicting emanation coefficient for different grain sizes.

Environmental evaluation of natural radioactivity in soil near a lignite-burning power plant in Turkey

Natural radionuclides are released into the environment together with fly ash from the coal-burning power plant and cause an increase in the natural radioactivity in environmental samples. The study concerns to the evaluation the influence of Kangal lignite-burning power plant (LBPP) with a power of 457 MWe, which has been in operation since 1989, on natural radionuclide a concentration in surface soil samples around it. Activity concentrations of natural radionuclides (²²⁶Ra, ²³²Th, ⁴⁰K and ²²²Rn) in the soil samples, and emanation coefficient (EC) and mass (ER_M) and surface (ER_S) exhalation rate of radon were determined by using a gamma-ray spectrometer with an HPGe detector. The average values of ²²⁶Ra, ²³²Th, ⁴⁰K and ²²²Rn, EC, ER_M and ER_S were found as 37±5, 17±3, 222±30Bqkg^-1 and 9±1kBqm^-3, 12%, 12.1 µBq kg^-1 s^-1 and 7.1mBqm^-2 s^-1, respectively. Absorbed gamma dose rate in outdoor air and the corresponding effective dose rate from external exposure and excess lifetime cancer risk were estimated to evaluate radiological hazards for human population. The results revealed that the Kangal LBPP has caused a small increment in ²²⁶Ra concentration in the studied area. No influence was observed for ²³²Th and ⁴⁰K.

Origin of radon concentration of Csalóka Spring in the Sopron Mountains (West Hungary)

We examined the Csalóka Spring, which has the highest radon concentration in the Sopron Mountains (West Hungary) (, yearly average of 227 ± 10 Bq L(-1)). The main rock types here are gneiss and micaschist, formed from metamorphism of former granitic and clastic sedimentary rocks respectively. The aim of the study was to find a likely source of the high radon concentration in water. During two periods (2007-2008 and 2012-2013) water samples were taken from the Csalóka Spring to measure its radon concentration (from 153 ± 9 Bq L(-1) to 291 ± 15 Bq L(-1)). Soil and rock samples were taken within a 10-m radius of the spring from debrish and from a deformed gneiss outcrop 500 m away from the spring. The radium activity concentration of the samples (between 24.3 ± 2.9 Bq kg(-1) and 145 ± 6.0 Bq kg(-1)) was measured by gamma-spectroscopy, and the specific radon exhalation was determined using radon-chamber measurements (between 1.32 ± 0.5 Bq kg(-1) and 37.1 ± 2.2 Bq kg(-1)). Based on these results a model calculation was used to determine the maximum potential radon concentration, which the soil or the rock may provide into the water. We showed that the maximum potential radon concentration of these mylonitic gneissic rocks (cpot = 2020 Bq L(-1)) is about eight times higher than the measured radon concentration in the water. However the maximum potential radon concentration for soils are significantly lower (41.3 Bq L(-1)) Based on measurements of radon exhalation and porosity of rock and soil samples we concluded that the source material can be the gneiss rock around the spring rather than the soil there. We determined the average radon concentration and the time dependence of the radon concentration over these years in the spring water. We obtained a strong negative correlation (-0.94 in period of 2007-2008 and -0.91 in 2012-2013) between precipitation and radon concentration.

A new method for estimating the coefficients of diffusion and emanation of radon in the soil

This paper describes a new method for determining the basic parameters of soil - diffusion and emanation coefficients related to the transfer of radon in the soil matrix, which are very useful for testing models, based on diffusion and characteristics of various soil matrices regarding the dangers of radon. The method is based on the measurement of radon in soil air on two small depths, differing twice. The paper presents the results of the determination of the parameters for covering loams and clays of Tomsk (Russian Federation), obtained by this method.