• Journal of the Korean Society of Radiology
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• v.9 no.4
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• pp.257-261
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• 2015

Radon is produced after the Uranium-238 and thorium-232 undergone radioactive decay process is a colorless, odorless inert gas is stored in a basement or an enclosed space. Building materials are made by a rock or soil materials. Form of radon gas is introduced into the lungs through the respiratory tract and deposited in the lungs or bronchial Daughter nuclides radon causes lung cancer. In this study, To subject the Constructed Apartment in Gwangju Gwangsan-Gu, the position is closed window and opened window was measured using a measuring instrument for radon. The measured results indicate that the measurement was carried out in concentrations of radon gas measured at Newly Constructed Apartment is low than United states in the radon concentration in air public 4 pCi called radon gas baseline maximum allowable concentrations. The exposure caused by radon concentration of new construction apartment when on the measurement results is expected to be insignificant. However, when radon gas like this is that it accumulates in the body and lungs get damaged due to exposure, such as lung cancer often open the windows to reduce the radon concentration measurements, such as in radiation protection aspects to the ventilation to reduce exposure it is considered necessary.

• Journal of Radiation Protection and Research
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• v.7 no.1
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• pp.17-22
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• 1982

Measurement of the radon concentration close to the ground surface can be used in search of environmental radiation for human safety, exploration for uranium, premonitory signals from earthquakes. We can detect radons in soil gas by alpha particle track method using the plastic track detectors, cellulose nitrate (LR115-Type 2 and CA80-15, Kodak $Path\'{e}$) and CR-39. For present works, radon cups having these detectors were made in our laboratory and their conversion factor was determined. A typical conversion factor was $1tr/cm^2{\cdot}30days=1.2{\times}10^{-2}pCi/l$. In the radon cups, some of $CaSO_4$ were used as desiccant for reducing the moisture effects on plastic track detectors. With these radon cups, underground radon concentrations of Kyungpook area were measured. Average radon concentration in Daegu from Jan. 1981 to Feb. 1982 was 39.7pCi/l. From Aug. 1981 to Feb. 1982, average radon concentrations of Daegu, Angang, Kyungju, Pohang, Chungha, and Andong were 31.8pCi/l, 124.5pCi/l, 127.0pCi/l, 79.1pCi/l, 144.4pCi/l, and 70.9pCi/l, respectively. The results were compared with the environmental radiation measured by TLD method.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.1
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• pp.71-84
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• 2017

Radon, which enters the interior environment from soil, rocks, and groundwater, is a radioactive gas that poses a serious risk to humans. Indoor radon concentrations are measured to investigate the risk of radon gas exposure and reliable radon concentration mapping is then performed for further analysis. In this study, we compared the predictive performance of various univariate kriging algorithms, including ordinary kriging and three nonlinear transform-based kriging algorithms (log-normal, multi-Gaussian, and indicator kriging), for mapping radon concentrations with an asymmetric distribution. To compare and analyze the predictive performance, we carried out jackknife-based validation and analyzed the errors according to the differences in the data intervals and sampling densities. From a case study in South Korea, the overall nonlinear transform-based kriging algorithms showed better predictive performance than ordinary kriging. Among the nonlinear transform-based kriging algorithms, log-normal kriging had the best performance, followed by multi-Gaussian kriging. Ordinary kriging was the best for predicting high values within the spatial pattern. The results from this study are expected to be useful in the selection of kriging algorithms for the spatial prediction of data with an asymmetric distribution.

• Economic and Environmental Geology
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• v.51 no.6
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• pp.553-566
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• 2018

The occurrence of natural radionuclides like uranium and radon in groundwater was hydrochemically examined based on 40 well groundwaters in Mungyeong area. The range of electrical conductivity (EC) value in the study area was $68{\sim}574{\mu}S/cm$. In addition to the increase of EC value, the content of cations and anions also tends to increase. Uranium concentrations ranged from $0.03{\sim}169{\mu}g/L$ (median value, $0.82{\mu}g/L$) and radon concentrations ranged from 70~30,700 pCi/L (median value, 955 pCi/L). Only 1 out of 40 wells (2.5%) showed uranium concentration exceeding the maximum contaminant level (MCL; $30{\mu}g/L$) proposed by the US Environmental Protection Agency (EPA). Radon concentrations of eight wells (20%) exceeded AMCL(Alternative maximum contaminant level) of the US EPA (4,000 pCi/L). Four out of those eight wells even exceeded Finland's guideline level (8,100 pCi/L). When concentrations of uranium and radon were investigated in terms of geology, the highest values are generally associated with granite. The uranium and radon levels observed in this study are low in comparison to those of other countries with similar geological settings. It is likely that the measured value was lower than the actual content due to the inflow of shallow groundwater by the lack of casing and grouting.

• The Journal of Engineering Geology
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• v.22 no.4
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• pp.427-437
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• 2012

A total of 100 groundwater samples were collected from the Nonsan area and the behaviors of uranium and radon as natural radionuclides were investigated with respect to other physicochemical components in the groundwater in order to understand their occurrence, properties, and origins. Radionuclide levels were used to construct detailed concentration maps. The concentration of uranium ranges from 0 to 378 ${\mu}g/L$, with an average of 8.57 ${\mu}g/L$, standard deviation of 42.88 ${\mu}g/L$, and median of 0.56 ${\mu}g/L$. The correlation coefficient between uranium and radon is 0.42, whereas these radionuclides show no relation with other physicochemical components in groundwater. It is noteworthy that the uranium level in most samples (97% of the samples) is less than 30 ${\mu}g/L$, where the bedrock of the aquifer is granite or complex rocks located along the boundary between granite and metamorphic rocks. In the Okcheon metamorphic belt, the uranium concentration of most groundwater is less than 1 ${\mu}g/L$. Radon levels varies from 128 to 9,140 pCi/L, with an average of 2,186 pCi/L, standard deviation of 1,725 pCi/L, and median of 1,805 pCi/L. High radon levels (> 4,000 pCi/L) are most common in regions of Jurassic granite, whereas low radon areas are found in regions of sedimentary rock. In conclusion, the distribution and occurrence of radionuclides are intimately related to the basic geological characteristics of the rocks in which the radiogenic minerals are primarily contained.

• The Journal of Engineering Geology
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• v.23 no.4
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• pp.477-491
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• 2013

Natural radionuclides in groundwater in the Danyang area were investigated to characterize the behaviors of uranium and radon with respect to lithology and physico-chemical components, which can aid our understanding of their occurrence, properties, and origins. To this end, a total of 100 groundwater samples were collected and analyzed, and radionuclide levels were used to construct detailed concentration maps. The water type of the groundwater, assessed using a Piper diagram, is mainly Ca-Na-$HCO_3$. The concentrations of uranium range from 0.02 to $251.0{\mu}g/L$ (average, $3.85{\mu}g/L$) and only 1% exceed USEPA's MCL (Maximum Contaminant Level). Uranium is enriched in groundwaters of Cretaceous granites and Precambrian metamorphic rocks, whereas it is depleted in groundwaters of sedimentary rocks. The concentrations of radon range from 13 to 28,470 pCi/L (average, 2397 pCi/L). Only 15% of the samples exceed AMCL (Alternative Maximum Contaminant Level) of 4000 pCi/L. The radon concentration is highest in groundwater of Cretaceous granites and lowest in groundwater of sedimentary rocks. In conclusion, the distribution and occurrence of radionuclides are intimately related to the basic geological characteristics of the rocks in which the radiogenic minerals are primarily contained. The behavior of uranium is only weakly related to that of radon (correlation coefficient = 0.15). There are also weak correlations between radionuclides and the main chemical components, pH, EC, Eh, and well depth. Of note, the correlation coefficient between radon and $SiO_2$ is 0.68, and that between radon and $HCO_3$ is -0.48. Factor analysis shows that radionuclides behave somewhat independently of each other because there are no significant factors that control the behavior of chemical components as well as radionuclides. The detailed concentration maps during this study will be used to establish useful database of radionuclide distribution and geological properties throughout Korea.

• Journal of the Korean Society of Radiology
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• v.5 no.5
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• pp.231-235
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• 2011

Radium is rock or soil of crust or uranium of building materials and thorium after radioactivity collapse process are created colorless and odorless inert gas that accrue well in sealed space like mine or basement. It inflow to lung circulate respiratory organ and caused lung cancer because of deposition of lung or bronchial tubes. Radium sheath of medical institution treat person's life is possible big danger to professional regarding radioactivity who has much amount exposed radioactivity and weaker immune patient. so we do this test. Using measuring instrument at test is real time radium measuring instrument, Professional Continuous Radon monitor, and measuring places are basement first floor and second floor of two hospitals and measure from 10 a.m to 3 p.m. Measurement result of Professional Continuous Radon monitor is minimum 14.8 Bq/$m^3$ to maximum 70.3 Bq/$m^3$ and show domestic baseline below 148 Bq/$m^3$, effective dose-rate is minimum 0.296 mSv to maximum 1.406 mSv that show 2.4 mSv, 10~58.3% level, exposed radiation amount from nature radiation one year.

• The Journal of Engineering Geology
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• v.24 no.4
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• pp.535-550
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• 2014

The origins and varieties of natural radioactive materials, including uranium and radon-222, were examined in a drilled borehole extending to a depth of 120 m below the surface in the Goesan area. In addition to core samples, eight groundwater samples were collected at different depths, using a double packer system and bailer, and their geochemical characteristics were determined. Most of the rock samples from the drilled core consisted of granite porphyry, with sedimentary rocks (slate, carbonate, or lime-silicates) and pegmatite occurring in certain sections. The pH of samples varied from 7.8 to 8.4, and the groundwater was of a Na-$HCO_3$type. Uranium and thorium concentrations in the core were < 0.2-14.8 ppm and 0.56-45.0 ppm, respectively. Observations by microscope and an electron probe microanalyzer (EPMA) showed that the mineral containing the natural radioactive materials was monazite contained in biotite crystals. The uranium, which substituted for major elements in the monazite, appeared to have dissolved and been released into the groundwater in a shear zone. Concentrations of Radon-222 in the borehole showed no close relationship with levels of uranium. The isotopes of noble gases, such as helium and neon, would be useful for analyzing the origins and characteristics of the natural radioactive materials.

• Nuclear Engineering and Technology
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• v.56 no.5
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• pp.1781-1795
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• 2024

This study investigated the levels of radioactivity in soil surrounding a phosphate fertilizer factory in Egypt, aiming to assess potential risks to the population exposed to radiation. Concentrations of ²³⁸U, ²²⁶Ra, ²³²Th, and ⁴⁰K were measured in soil samples collected from two subsites: one near the factory (subsite 1) and another further away (subsite 2). Two different systems were used for measuring radioactivity, a high-purity gamma ray spectroscopy system with an HPGe detector for gamma-emitting isotopes and a CR-39 solid nuclear track detector for alpha-emitting radon gas. Subsite 1, located close to the factory, displayed significantly elevated levels of ²²⁶Ra compared to global background levels (514 and 456 Bq/kg vs. 35 Bq/kg). Additionally, the concentrations of ²³⁸U (241.06 Bq/kg vs. global average 35 Bq/kg), ²³²Th (16.15 Bq/kg vs. global average 30 Bq/kg), and ⁴⁰K (146.36 Bq/kg vs. global average 400 Bq/kg) were all above global averages. Furthermore, a high concentration of radon gas (337.06 μSv/y) was measured at subsite 1. The strong positive correlation observed between ²²⁶Ra and ²³⁸U (0.96256) provides further evidence of potentially elevated radioactivity levels near the factory. In contrast, subsite 2, situated farther from the factory, exhibited natural radioactive background levels within international limits. Quantitative analysis revealed that gamma ray absorbed doses for ²²⁶Ra and ²³²Th exceeded global averages in some samples. Specifically, ²²⁶Ra doses ranged from 7.8 to 46.26 ppm (exceeding the 20 ppm global average in some cases), and ²³²Th doses ranged from 1.98 to 9.14 ppm (exceeding the 10 ppm global average in some cases). The concentration of ⁴⁰K, however, remained within the global range (0.07%-0.69 %). The observed imbalances in the ratios of Th/U (0.17-0.24 Bq/kg and 0.73-0.24 ppm) and U/Ra (0.81-0.73 Bq/kg and 0.73-0.17 ppm), both of which are significantly lower than their respective global averages of 4 and 2.4, point towards the presence of fertilizer-derived contamination. This conclusion is further supported by the high phosphate concentrations detected in the samples. Overall, this study suggests that radioactive contamination near the phosphate fertilizer factory significantly exceeds global background levels and international limits in some cases. This raises concerns about potential risks posed to surrounding agricultural land and crops.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1431-1438
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• 2022

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 93, 77, 92 and 938 Bq kg^-1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y^-1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30×10^-3, 4.26×10^-3, 0.62×10^-3, and 25.61×10^-3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.