• Journal of Environmental Science International
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• v.2 no.2
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• pp.123-133
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• 1993

Shingal reservoir is a relatively small (211ha) and shallow impoundment, and approximately 25 ha of its sediment is exposed after spring drawdown. At least 14 vascular p13n1 species germinate on the exposed sediment, but Persimria vulgaris Webb et Moq. quickly dominates the vegetation. In order to estimate the role of the vegetation in the dynamics of heavy metal pollutants in the reservoir, Cu concentration of water, fallout particles, exposed sediment, and tissues of p. vulgaris, Ivas analyzed. Cu content in reservoir water decreased from $13.10mg/m^2$ on May 15 (before dralvdown) to $3.08mg/m^2$ in June 1 (after drawdown), mainly due to the loiwering of water level. Average atmospheric deposition of Cu by fallout particles was $10.84 {\mu}g/m^2/day$. Cu content in the surface 15cm of exposed sediment decreased from $5.094g1m^2$ right after drawdown, to $0.530g/m^2$ in 41 days, which is a 89.6% decrease. Therefore up to 99.7% of Cu in the reservoir appears to exist in the sediment. only 0.3% in water If the rate of atmospheric Input by fallout particles is assumed to have been the same since 1958, when the reservoir was completed, cumulative input of Cu during the 38 years would have been $150.35mg/m^2$, which is only 3.0% of Cu content in sediment right after drawdown. Therefore, most of Cu in the Shingal reservoir must have been transported by the Shingal-chun flowing into the reservoir, Standing crop of vegetation on the exposed sediment 41 days after drawdown was $730.67g/m^2$, of which 630.91g/m2 was p. vulgaris alone, and Cu content in P vulgaris at this time was $6.612mg/m^2$. This was only 0.13% of Cu in the exposed sediment, but was 50.5% of Cu in water before drawdown, or 167% of the average annual input of Cu by atmospheric deposition. If other plants were assumed to absorb Cu to the same concentration as p. vulgaris, total amount of Cu absorbed in 41 days by vegetation on the exposed sediment is estimated to be 1913.3 g, which is a considerable contribution to the purification of the reservoir water.

• Journal of Environmental Science International
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• v.2 no.2
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• pp.29-29
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• 1993

Shingal reservoir is a relatively small (211ha) and shallow impoundment, and approximately 25 ha of its sediment is exposed after spring drawdown. At least 14 vascular p13n1 species germinate on the exposed sediment, but Persimria vulgaris Webb et Moq. quickly dominates the vegetation. In order to estimate the role of the vegetation in the dynamics of heavy metal pollutants in the reservoir, Cu concentration of water, fallout particles, exposed sediment, and tissues of p. vulgaris, Ivas analyzed. Cu content in reservoir water decreased from $13.10mg/m^2$ on May 15 (before dralvdown) to $3.08mg/m^2$ in June 1 (after drawdown), mainly due to the loiwering of water level. Average atmospheric deposition of Cu by fallout particles was $10.84 {\mu}g/m^2/day$. Cu content in the surface 15cm of exposed sediment decreased from $5.094g1m^2$ right after drawdown, to $0.530g/m^2$ in 41 days, which is a 89.6% decrease. Therefore up to 99.7% of Cu in the reservoir appears to exist in the sediment. only 0.3% in water If the rate of atmospheric Input by fallout particles is assumed to have been the same since 1958, when the reservoir was completed, cumulative input of Cu during the 38 years would have been $150.35mg/m^2$, which is only 3.0% of Cu content in sediment right after drawdown. Therefore, most of Cu in the Shingal reservoir must have been transported by the Shingal-chun flowing into the reservoir, Standing crop of vegetation on the exposed sediment 41 days after drawdown was $730.67g/m^2$, of which 630.91g/m2 was p. vulgaris alone, and Cu content in P vulgaris at this time was $6.612mg/m^2$. This was only 0.13% of Cu in the exposed sediment, but was 50.5% of Cu in water before drawdown, or 167% of the average annual input of Cu by atmospheric deposition. If other plants were assumed to absorb Cu to the same concentration as p. vulgaris, total amount of Cu absorbed in 41 days by vegetation on the exposed sediment is estimated to be 1913.3 g, which is a considerable contribution to the purification of the reservoir water.

• Journal of Nuclear Fuel Cycle and Waste Technology
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• v.1 no.1
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• pp.49-55
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• 2013

To characterize quantitatively the transport of $^{99}Tc$ and the global fallout ($^{137}Cs$, $^{90}Sr$, and $^{239+240}Pu$) for soils in Korea, the transport parameters of a convective-dispersion model, apparent migration velocity, and apparent dispersion coefficient were estimated from the vertical depth profiles of the radionuclides in soils. The vertical profiles of $^{99}Tc$ were measured from a pot experiment for paddy soil that had been sampled from a rice-field around the Gyeongju radioactive waste repository in Korea, and the vertical depth distributions of the global fallout $^{137}Cs$, $^{90}Sr$, and $^{239+240}Pu$ were measured from the soil samples that were taken from local areas in Korea. The front edge of the $^{99}Tc$ profiles reached a depth of about 12 cm in 138 days, indicating a faster movement than the fallout radionuclides. A weak adsorption of $^{99}Tc$ on the soil particles by the formation of Tc(VII) and a high water infiltration velocity seemed to have controlled the migration of $^{99}Tc$. The apparent migration velocity and dispersion coefficient of $^{99}Tc$ for the disturbed paddy soil were 2.88 cm/y and 6.3 $cm^2/y$, respectively. The majority of the global fallout $^{137}Cs$, $^{90}Sr$, and $^{239+240}Pu$ were found in the top 20 cm of the soils even after a transport of about 30 years. The transport parameters for the global fallout radionuclides were 0.01-0.1cm/y ($^{137}Cs$), 0.09-0.13cm/y ($^{90}Sr$), and 0.09-0.18cm/y ($^{239+240}Pu$) for the apparent migration velocity: 0.21-1.09 $cm^2/y$ ($^{137}Cs$), 0.12-0.7$cm^2/y$ ($^{90}Sr$), and 0.09-0.36$cm^2/y$ ($^{239+240}Pu$) for the apparent dispersion coefficient.

• Korean Journal of Soil Science and Fertilizer
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• v.15 no.4
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• pp.207-212
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• 1982

Soils and sediments have been uniquely tagged by radioactive isotopes as a result of nuclear test explosions in the 1950's and 1960's. Fallout $^{137}Cs$ strongly fixed to fine soil particles, was measured in sediment profiles in Larto Lake to calculate the sedimentation rate as a time dependence. The Lake sediment profiles indicated an average rate of 1.6 to 3.1 cm/yr of sediment deposition since 1958. The rate of sediment depositions clearly decreased with time. Particle size distribution in sediment was reflected almost fine particles in lake.

• Nuclear Engineering and Technology
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• v.55 no.8
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• pp.2802-2811
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• 2023

In a first-of-its-kind study, terrestrial radionuclide concentrations were measured in 35 topsoil samples from the outskirts of Dhaka using HPGe gamma-ray spectrometry to assess the radiological consequences of such a vast number of brick kilns on the plant workers, general as well as dwelling environment. The range of activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K is found at 19 ± 3.04 to 38 ± 4.94, 39 ± 5.85 to 57 ± 7.41, and (430 ± 51.60 to 570 ± 68.40) Bq/kg, respectively. ²³²Th and ⁴⁰K concentrations were higher than the global averages. Bottom ash deposition in lowlands, fly ash buildup in soils, and the fallout of micro-particles are all probable causes of the elevated radioactivity levels. ¹³⁷Cs was found in the sample, which indicates the migration of ¹³⁷Cs from nuclear accidents or nuclear fallout, or the contamination of feed coal. Although the effective dose received by the general public was below the recommended dose limit but, most estimates of hazard parameters surpass their respective population weighted global averages, indicating that brick kiln workers and nearby residents are not safe due to prolonged exposures to terrestrial radiation. In addition, the soil around sampling sites is found to be unsuitable for agricultural purposes.

• Economic and Environmental Geology
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• v.33 no.3
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• pp.195-204
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• 2000

order to investigate physical characteristics and element concentrations of sediments, coastal bottom sediments were collected at 20 stations in the vicinity of Youngkwang Nuclear Power Plant. After air drying of samples in the laboratory. article size distribution was examined by Master sizer (X-350F), radio-activity by HPGe ${\gamma}$-spectrphotometer, and element concentrations by ICP-AES and AAS. According to particle size analysis , sediments are mainly composed of silt fraction weith 23% of sand, 65% of silt and 12% of clay on average. Most sediments are derived from muddy environment that silt dominates with the characteristics of 5.3${\varsigma}$ mean particle size, poorly sorted, very fine skewed and lepto-kurtic. Only two sediments are well sorted with sandy silt owing to wind, winnowing action, tide and current andits complex reactions. Element concentrations in the coastal bottom sediments are relatively high at finer sediment and show significant relationship with grain size. Index of geoaccumulation by heavy metals at every sampling station is classified as practically unpolluted. The radioactivities of the sediments were measured for 15 isotope elements, and 2 elements of K-40 and Cs-137 were detected in most sediments. The K-40 is the natural nuclide and the artificial nuclide of Cs-137 was thought to be derived from the fallout of past nuclear weapon test. The results of correlation coefficient between grain size and radioactivity shows that the activity of Cs-137 significantly increases in finer grain.

• Korean Journal of Organic Agriculture
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• v.3 no.1
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• pp.11-22
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• 1994

Exposing plant organs to high doses of ionizing irradiation, penetrating into the plant tis-sues and cells, along the track structure of particles, lesions, and sublesions are formed on the molecules and organelles. As a result, disorders in the growth and development as well as chlorophyll-deficiency symptoms occur. The time scale of their reparation, recovery and over compensation during ontogenesis, constitutes a question of high theoretical and practical importanced, with special regard to nuclear fallout. With an aim to model the “ut supra”stated phenomena, the seeds of bean, Echo elit licensed variety, were irradiated by 300 Gy dose of X-ray-irradiation (120 kV:4.5 mA). According to the data obtained, the biosynthesis of photosynthetic pigments, will have been completed by the beginning of flowering. In consequence of the overcompensation of the repairing processes, the organs of plants developed from irradiated seeds, showed a partly differing correlative growth, compared to those of control plants. In order to characterize the vivo response of radiation-injured plants, a new method and approach were used. The changes of the electric capacitance of the plants during their ontogenesis, were continously monitored and recorede via a computer-aided and controlled measurement. In view of the data collected in such a way, the repairing plants may respond more quickly and intensively to the changes of environmental factors.

• Journal of Korean Tunnelling and Underground Space Association
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• v.19 no.4
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• pp.589-609
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• 2017

This study carried out the density and energy dispersive X-ray spectroscopy and particle size analysis which are the physical characteristics of coal dust by collecting samples of coal dust in the five domestic mines to control the coal dust through ventilation in the workplace for coal mining in the country. This will contribute to a more comfortable working environment by understanding the physical characteristics of the coal dust which is derived from any hard coal produced domestically. In particular, the result of PSA analysis showed that the size of coal dust sample for this study ranged from $0.007{\sim}88.614{\mu}m$ were the particles less than $3.5{\mu}m$, the size range responsible for pneumoconiosis. To observe the flow of coal dust collected on the wind speed, the fallout of coal dust produced by the wind tunnel for the wind was measured and the particle size analysis of coal dust fallout was carried out. In addition, airborne dust is measured according to the mine velocity by using a multi-stage Anderson sampler in the mine where fine dust is generated in a large amount and the wind speed is found out to control the coal dust below $3.5{\mu}m$. In addition, natural ventilation pressure of A mine was calculated to prevent over design of the main fan.