• Economic and Environmental Geology
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• v.31 no.1
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• pp.11-20
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• 1998

The effects of the major cations ($Ca^{2+}$, $Mg^{2+}$, $K^+$, $Na^+$), complex-forming anions ($SO_4{^{2-}}$, $HCO_3{^-}$), and solution pH on the adsorption of $^{137}Cs$ and $^{90}Sr$ by kaolinite in groundwater chemistry were investigated. Three-dimensional Kd modelling designed by a statistical method was attempted to compare the relative effect among hydrated radii, charge and concentration of competing cations on the adsorption of Cs and Sr. The modelling results indicate that the hydrated radii of competing cations is the most important factor, and then their charges and concentrations are also important factors in order. The property of zeta potential of kaolinite particles was discussed in terms of the amphoteric reactions of a kaolinite surface affecting the adsorption of Cs and Sr. The ionic strength of competing cations on the adsorption of Cs and Sr exerts a greater effect than the solution pH. The sorption behaviour of Sr on kaolinite is also highly dependent on the concentration of bicarbonate. The speciation of Sr and the saturation state of a secondary phase were thermodynamically calculated by a computer program, WATEQ4F. This indicates that the change in solution pH with the concentration of bicarbonate and the precipitation of a strontianite ($SrCO_3$) are major factors controlling Sr adsorption behaviour in the presence of bicarbonate ion.

• Journal of Korean Society of Forest Science
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• v.98 no.6
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• pp.669-675
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• 2009

The purpose of this study was to examine the influence of land use change in the forest catchment on sedimentation rate at the outlets of rivers in Kushiro Mire that have been impacted by forest clearing, agricultural activity and river regulation. We analysed Caesium-137(Cs-137) concentration in sediment cores, and we estimated sedimentation rates and Cs-137 inventories over the last 50 years. Cs-137 from atomic bomb testing first entered the environment in 1954 which provides easily identifiable chronological markers in the sediment. Because Cs-137 is strongly absorbed into sediment particles, its redistribution occurs in association with sedimentary particles. Since the 1950s, the forest catchment areas draining into the mire have been developed intensively from forest areas to agricultural lands. The sediment accumulations at the outlets of rivers after 1954 ranged from 36 to 148 cm. The Cs-137 inventory is significantly greater than the reference sites which reflected natural accumulation conditions because sediment containing Cs-137 was carried from catchments into the outlets of the rivers. In addition, the Cs-137 inventory was correlated with the sedimentation rate. However, the Cs-137 inventories in Kuchoro and Kushiro river profiles were slowly increased with the sedimentation rates. This is because the sediment originating from scoured areas such as streambeds and banks contains a low level of Cs-137 concentration.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.24-29
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• 1983

The effects of temperature on the uptake of $^{137}Cs$ from seawater and on the retention after its uptake by the clam Cycling sinensis was investigated under laboratory conditions. The clams exhibited a greater bioaccumulation of $^{137}Cs$ in $25^{\circ}C$-acclimated animals than those acclimated at $15^{\circ}C$. The viscera of the clams reached the highest bioconcentration factor after 14 days uptake from seawater, but the tissue distribution pattern of $^{137}Cs$ was little influenced, if any, by the uptake temperature. The uptake rate slightly decreased with an increase of temperature in order of $10^{\circ}C$. The radionuclide accumulated in clams was released again in a radionuclide-free seawater according to a two-exponential compartment model. A temperature increase of $10^{\circ}C$ reduced the biological half-life of the long-lived component with a factor of about two, whereas it caused no change in the short-lived component.

• Nuclear Engineering and Technology
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• v.16 no.2
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• pp.64-69
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• 1984

With regard to the radioactive waste disposal, adsorption properties and migration rates have been evaluated for Cs-137 and Sr-90 with the domestic clay sampled from Cnyang, Sanchong and Mooan. Sorption coefficients (Ksorp) were determined by batch experiments. The measured values of Ksorp were ranged from 8000 to 17,000 ml/gr for Cs-137 of 0.1$\mu$Ci/ml, and from 10,000 to 15,000m1/gr for Sr-90 of 0.l$\mu$Ci/ml. Remarkably, Mooan clay showed lower values of Ksorp than those of the others. This could be explained by the poor soprtion capacity of the quartz found only in the Mooan clay. For the quantitative analysis, sorption isotherm equations of Freundlich type were made with the obtained values of Ksorp. $C_{R}$=18.0 $C_{A}$$^{0.74}$ : Cs-137, $C_{R}$=0.84 $C_{A}$$^{0.45}$ : Sr-90. By introducing the BOX model combined with the above relationships, simulation of underground nuclide movement was carried out. The results showed that the domestic clays could be the effective backfill material for repositories.itories.ies.

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.236-237
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• 2010

• Proceedings of the Korean Nuclear Society Conference
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• 2002.05a
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• pp.436.1-436
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• 2002

• Journal of radiological science and technology
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• v.46 no.1
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• pp.37-42
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• 2023

Most of research on environmental radioactivity is conducted in areas near nuclear power plants, so basic data about the distribution of environmental radioactivity in soil in other areas are insufficient. Therefore, in this study, divide into four categories by the land development characteristics of Incheon and the purpose of development, and confirm the stability of the Incheon through soil sample collection and gamma-ray analysis based on ⁴⁰K, ¹³⁷Cs and ²²⁶Ra (²¹⁴Pb, ²¹⁴Bi). The spectrum obtained by measuring for 80,000 seconds by using the HPGe detector was analyzed by Genie 2000 program. Soil radioactivity concentrations in urban parks of Incheon area are generally within a safe range compared to the results of the Nuclear safety and security commission. However, as ¹³⁷Cs was detected in one park, which will require continuous monitoring.

• Journal of Food Hygiene and Safety
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• v.35 no.1
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• pp.31-36
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• 2020

To ensure food safety of berries from radioactive contamination, radioactivity monitoring was conducted with a total 258 samples of the berries and processed berry products distributed in Gyeonggi-do, South Korea, from 2016 to 2018. The concentration of artificial radionuclides, ¹³¹I, ¹³⁴Cs and ¹³⁷Cs, was analyzed using gamma-ray spectrometry. ¹³¹I and ¹³⁴Cs were not detected above the MDA (Minimum Detectable Activity) value from any of the samples. However, the range of radioactivity concentration of ¹³⁷Cs was 0.69-808.90 Bq/kg in 39 cases of berries. ¹³⁷Cs was detected at 0.70-3.29 Bq/kg from 6 cases of domestic berries, which were manufactured from imported raw materials. Among 33 cases of imported berries, ¹³⁷Cs was detected at 0.69-808.90 Bq/kg. The concentrations of ¹³⁷Cs in 1 case of blueberry powder product (808.90 Bq/kg) and 2 cases of lingonberry powder products (103.93, 188.46 Bq/kg) exceed domestic maximum radioactivity limits, and these were detected in the berries from Poland. These results suggest that monitoring system for imported berries and processed berry products should be continuously intensified to secure food safety.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.161-166
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• 2005

In KAERI, about 3,100 drums containing soil have been stored. The soils were generated from the decommissioning process of Seoul office in 1988. Those soils occupy about $27\%$ of the capacity of the radioactive waste storage facility and make it difficult to maintain the storage facility. The major radioactive nuclides contained in the soils were expected to be Co-60 and Cs-137. As 16 years have passed, the radioactivity of those nuclides have decayed a lot. In this study, as a basis of regulatory clearance, radionuclides and radioactivity concentration of soils were analyzed. As a result, there are only Co-60 and Cs-137 in soils as ${\gamma}-emitters$. The total concentration of ${\gamma}-emitters$ in soil is analyzed as about $0.01\;{\sim}\;0.12$ Bq/g. As the soils are expected to be regulatory cleared in 2009, those concentrations will decay to be less than 0.1 Bq/g. This concentration can be meet the regulatory criteria suggested by IAEA. The regulatory clearance will be proceeded based on not only the assessment results of environmental influence but also related regulations.

• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.51-58
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• 1996

Underground migration of $^{54}Mn,\;^{60}Co,\;^{85}Sr\;and\;^{137}Cs$ in paddy and upland conditions was studied through two years' greenhouse experiment. At early and late growth stages of rice, soybean, Chinese cabbage and radish, a mixed solution of the radionuclides was applied to the water or soil surfaces of the culture boxes filled with an acidic loamy-sandy soil for the upper 20cm. Soil was sampled in layers upto $15{\sim}20cm$ down after harvest. Soil concentrations of the radionuclides decreased exponentially with increasing soil depth and more than 80% of the radioactivities remained in top $3{\sim}4cm$. The mobility of the radionuclides decreased in the order of $^{85}Sr>^{54}Mn>^{60}Co{\geq}^{137}Cs$. Downward migrations of the radionuclides were the greatest in rice soil and the lowest in soybean soil which was fertilized with the least amount of N, P and K. Differences in depth profiles between two application times indicate that the amount of daily migration from $0{\sim}1cm$ layer to the lower area decreases with increasing time after deposition. By a simultaneous addition of KCl and lime following the earlier application, downward migration in soybean, Chinese cabbage and radish soils changed little or retarded more or less but that in rice soil accelerated a little.