• Journal of Environmental Science International
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• v.20 no.9
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• pp.1165-1182
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• 2011

The evaluation of potential submarine groundwater is an important research topic for exploring an alternative water resource. Two different approaches, water budget analysis and Rn mass balance method, were employed to investigate the annual variation of submarine groundwater discharge in 2010 at a marine watershed located at the south-eastern part of Korean Peninsula. In order to obtain reliable hydrological data during study period, temporal and spatial variations of rainfall and soil moisture had been collected and hydro-meterological data such as temperature, humidity and wind speed were collected The runoff response was simulated using SCS-CN method with spatial distributions of landuse and soil texture from GIS analysis. Six different methods were used to estimate the monthly variation of evapotranspiration and field measurements of soil moisture were used to account for the infiltration. Comparisons of infiltration and surface runoff between simulation and water balance with measurements showed coincidence. The water budget analysis and Rn mass balance method provide mean daily submarine groundwater as 5.35 and 4.07 $m^3/m/day$ in 2010, respectively.

• Journal of Soil and Groundwater Environment
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• v.17 no.2
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• pp.22-27
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• 2012

$^{226}Ra$ in groundwater could be analyzed by various methods. LSC (liquid scintillation counter) is used to measure its activity of Ba co-precipitates with Hisafe III scintillation cocktail solution. Counting efficiency was obtained using NIST $^{226}Ra$ standard solution in triplicate and calculated $^{226}Ra$ concentration using the efficiency values. $^{226}Ra$ values of 19 groundwaters having Gross-${\alpha}$ concentrations of more than 5 pCi/L ranged from ND (${\leq}$ 0.1 pCi/L) to 1.18 pCi/L. Geologic settings of the 19 areas are composed of granitic rocks of Pre-Cambrian and Jurassic and Cretaceous, gneiss (schist) of Pre-Cambrian, and volcanic rocks of Cretaceous. No relationship was shown among $^{226}Ra$ a concentrations and in-situ water quality data, and Gross-${\alpha}$, uranium, radon concentrations.

• The Journal of Engineering Geology
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• v.26 no.4
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• pp.531-549
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• 2016

The purpose of this study is to analyze the relationship of hydrochemistry, geology, fault with occurrence of uranium and radon-222 from the groundwater in the Yeongdong area. In this study, 49 groundwater and 4 surface water samples collected in the study area were collected on two separate occasions. The surface radioactivities were measured at 40 points to know the relationship between the occurrence of uranium in groundwater and surface geology. The chemical composition of groundwater showed three types : $Ca-HCO_3$, $Na-HCO_3$ and $Ca-HCO_3(SO_4,\;NO_3)$. Two groundwater of 49 samples exceeded the maximum contaminant levels of uranium, $30{\mu}g/L$, proposed by the Ministry of Environment of Korea and 11 groundwater of 40 samples for Rn-222 concentrations exceeded the 148 Bq/L maximum contaminant level of US EPA. Most of unsuitable groundwater are located in the geological boundary related with the biotite gneiss and the surface radioactivities of rock samples showed no relationship with groundwater geochemical constituents. The strike-slip fault, Youngdong fault, is $N45^{\circ}E$ direction and the high concentrations of uranium in upper part of fault, consisted of granite and granitic gneiss are detected but in lower part, consisted of metamorphic sedimentary rock are not detected. It suggests that the natural radioactive concentrations are related with the geologic characteristics and the migration and diffusion of natural radioactive materials are affected by the fault.

• Analytical Science and Technology
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• v.29 no.2
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• pp.65-72
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• 2016

This study presented an analytical method for detecting radium in soils using a liquid scintillation counter (LSC). The isotope ²²⁶Ra was extracted from soil using the fusion method and then separated from interfering radionuclides using the precipitation method. Radium was coprecipitated as sulfate salts with barium (Ba) and then converted into Ba(Ra)CO₃, which is soluble in an acidic solution. The isotope ²²²Rn, the decay progeny of ²²⁶Ra, was trapped in a water immiscible cocktail and analyzed by LSC. The pulse shape analysis (PSA) level was estimated using ⁹⁰Sr and ²²⁶Ra standard solutions. The figure of merit was the highest at PSA 80, while the alpha spillover was the lowest at PSA 80. The counting efficiency was 243 ± 2% in a glass vial. This analytical method was verified with International Atomic Energy Agency (IAEA) reference materials, including IAEA-312, IAEA-314, and IAEA-315. The recovery ranged from 60–82%, while the relative bias between the measured value and the recommended value was less than 10%. The minimum detectable activity was 2.1 Bq kg⁻¹ with dry mass 1 g, the background count rate of 0.02 cpm, the recovery rate of 70% and counting time of 30 min.

• Journal of Radiation Protection and Research
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• v.26 no.4
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• pp.441-445
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• 2001

In this work we investigated distribution of the natural and artificial radioactive nuclides and level of the regional background in soil in Busan. For 45 points, the environmental radioactivity concentration of Busan surface soil is $14.38{\sim}57.03\;(mean\;:\;33.95)\;Bq{\cdot}kg^{-1}$ for $^{226}Ra,\;2.41{\sim}86.58\;(mean\;:\;51.08)\;Bq{\cdot}kg^{-1}$ for $^{228}Ra,\;223.64{\sim}1332.30\;(mean\;668.51)\;Bq{\cdot}kg^{-1}$ for $^{40}K$ and $<0.33{\sim}33.37\;(mean:13.74) Bq{\cdot}kg^{-1}$ for $^{137}Cs$. Also, in order to investigate vertical distribution for radioactivity, we examined radioactive concentration with mountain height. But there was no correlation between radiaoactivity distribution and mountain height. The $^{226}Ra/^{228}Ra$ and $^{226}Ra/^{40}K$ concentration ratios were $0.68{\pm}19 %$ and $0.06{\pm}34%$, respectively.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.565-583
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• 2020

In recent years, various social issues related to the natural radioactive elements detected in household goods and building materials are addressed, and should be solved promptly. In Korea, for more than 20 years, the Ministry of Environment has investigated the natural radioactive materials such as heavy metals, uranium, and radon in soil or groundwater. The origins of natural radioactive materials in them may have a close correlation with the geological factors including classification of rocks, petrogenetic origins, and deformation characteristics, but the exact geological correlations are not clarified because of the absence of the government policy preserved in the basement rocks, soils as well as groundwater in fault-related reservoirs. This study aims to perform a research on the correlation between the petrogeneses of the Phanerozoic plutonic rocks and natural radioactive concentrations in rocks (radon, uranium, thorium, potassium etc.) in Korea. Among the Phanerozoic plutonic rocks, alkaline plutonic rocks (syenite, monzonite and monzodiorite and alkali granite) show high U and Th concentrations by high solubilities of U, Th, Zr, REE, and Nb until the most extreme stages of magmatic fractionation (viz. crystal fractionation) due to high magma temperature and high alkalinity tendency. The highly fractionated high-K calalkaline and peraluminous granitic rocks (leucogranite, two-mica granite and leucocratic pegmatite are also U and Th concentrations compared with other less or medium fractionated granitic rocks (diorite, granodiorite and granite). The alkaline plutonic rocks are associated with intracontinental rifting and extensional environment after crustal thickening by collisional and subductional processes. In contrast, the dominant calc-alkaline granitic rocks in Korea are related to the arc environment of the subduction zone. In summary, the trends of the U, Th and K concentration from the Phanerozoic plutonic rocks in Korea are closely linked to the petrogenesis of the rocks in tectonic environment. The preliminary data for gamma-spectrometric mesurments of natural radionuclide contents (²²⁶Ra, ²³²Th and ⁴⁰K) in the Phanerozoic plutonic rocks show high values in the alkaline and highly fractionated granitic rocks.