• Korean Journal of Environmental Agriculture
• /
• v.16 no.1
• /
• pp.25-30
• /
• 1997

Absorption, distribution, metabolism and excretion of $^{14}C-carbofuran$(2,3-dihydro-2,2-dimethyl-7-benzofuranyl methylcarbamte) were studied in carp(Cyprinus carpio L.) after the treatment of carbofuran at the dose level of 43 parts per billion. Maximum radioactivities in tissues(liver, kidney, gut, gall bladder) and blood of carp were shown 12hrs after the treatment of $^{14}C-carbofuran$. Carbofuran was metabolized to 3-hydroxycarbofuran and 3-ketocarbofuran in liver and kindney of carp, and the major metabolite was 3-hydroxycarbofuran. Most radioactivity absorbed into the carp tissues was eliminated 3hrs after transfer of the carp to fresh water. The excretory metabolites were 3-ketocarbofuran(32.3%), 3-hydroxycarbofuran(52.8%) and an unknown metabolite(2.6%) during the period of 3hrs of the excretory experiment.

• Applied Chemistry for Engineering
• /
• v.28 no.2
• /
• pp.133-140
• /
• 2017

Increasing concerns on radioactive wastes have drawn much attention on the development of remediation technologies. Massive amounts of radioactive wastes generated from hospital and nuclear power plants were exposed to our environment. Although physicochemical removal methods were developed, an eco-friendly remediation method has not yet been demonstrated. Recently, an extremophilic bacterium has received much attention due to their extraordinary characteristics. Among them, Deinococcus radiodurans (D. radiodurans) strain was regarded as the best host organism for the removal of radioactive heavy metals and radionuclides, because of their superb characteristics like tolerance against the high level of radioactivity. In this article, we briefly introduced the extraordinary nature of D. radiodurans and also discussed the potential use of D. radiodurans strain for the removal of radioactive wastes.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.11a
• /
• pp.232-235
• /
• 2003

In general, the parameters of climate change include aerosol chemical compounds, aerosol optical depth, greenhouse gases(carbon dioxide, CFCs, methane, nitrous oxide, tropospheric ozone), ozone distribution, precipitation acidity and chemical compounds, persistent organic pollutants and heavy metals, radioactivity, solar radiation including ultra-violet and standard meteorological parameters. Over the last ten years, the monitoring activities of Korea regarding to the climate change have been progressed within the WMO GAW and ACE-Asia IOP programs centered at the observation sites of Anmyeon and Jeju Gosan islands respectively. The Greenhouse gases were pointed out that standard air quality monitoring techniques are required to enhance data comparability and that data presentation formats need to be harmonized and easily understood. Especially, the impact of atmospheric aerosols on climate depends on their optical properties, which, in turn, are a function of aerosol size distribution and the spectral reflective indices. Aerosol optical depth and single scattering albedo in the visible are used as the two basic parameters in the atmospheric temperature variation studies. The former parameter is an indicator of the attenuation power of aerosols, while the latter represents the relative strength of scattering and absorption by aerosols. For aerosols with weak absorption, surface temperature decreases as the optical depth increases because of the domination of backscattering. For aerosols with strong absorption, however, warming could occur as the optical depth increases. The objective of the study is to characterize the means, variability, and trends of Greenhouse gases and aerosol properties on a regional basis using data from its baseline observatories in Korea peninsula. A further goal is to understand the factors that control radiative forcing of the greenhouse and aerosol.

• Journal of the Korean Society of Radiology
• /
• v.5 no.1
• /
• pp.5-10
• /
• 2011

Based on basic concept of detection limit, sample measurement time & background measurement time was considered, and MDA values according to background measurement time and sample measurement time in land samples(river soil, surface soil, drinking water, underground water, surface water, pine leaf, mugwort) analysis among environmental samples were compared. Seeing the water sample analysis result, it was shown that most of the samples were not detected, and most of the samples in land specimen analysis showed to be below the detection limit of "Ministry of Education, Science and Technology Announcement Je-2008-28-ho", but $^{137}Cs$ which is one of artificial radioactive nuclide was detected in some samples. It can be traced back to 1950s and 1960s when nuclear tests were carried out in atmosphere and catastrophic Chernobyl atomic power station accident that caused fallouts in the sky, and this is common level of detection that can be observed worldwide. Seeing the result that the $^{134}Cs$(which is a isotope of $^{137}Cs$, and it has relatively short half life) was not detected in all samples, it can be considered it doesn't affect to the operation of atomic power station.

• Journal of Radiation Protection and Research
• /
• v.41 no.4
• /
• pp.418-423
• /
• 2016

Background: This work was to get information about $^{90}Sr$ contamination of the environment by using soil and moss from selected areas in Jeju Island, Korea. Materials and Methods: The activities of $^{90}Sr$ in soil and moss samples were investigated at nine locations of Jeju island, Korea. The soil samples have been collected at 4 sites of Jeju island during June to August of 2013, analyzed for vertical distribution of $^{90}Sr$ activities. The moss samples have been collected at 5 sites of Jeju island during November of 2011 to June of 2012, and analyzed for radioactive $^{90}Sr$. Results and Discussion: The $^{90}Sr$ vertical concentrations in the investigated soil samples were 2.77 to $18.24Bq{\cdot}kg^{-1}$ in eastern part, 1.69 to $18.27Bq{\cdot}kg^{-1}$ in northern part, 3.76 to $13.46Bq{\cdot}kg^{-1}$ in the western part and 1.09 to $8.70Bq{\cdot}kg^{-1}$ in the southern part of the Mt. Halla in Jeju island, respectively. Activities of $^{90}Sr$ show the highest value at the surface soil and decrease with depth. The activity concentration measured was in the range of 79.6 to $363Bq{\cdot}kg^{-1}$ -dry moss. Conclusion: This material is expected to be basis reference for survey of environmental radioactivity in Jeju Island.

• Journal of Korean Society of Environmental Engineers
• /
• v.38 no.10
• /
• pp.535-542
• /
• 2016

As one of the most cost-effective methods for surface emission measurements, flux chamber method has been used worldwide. It can be classified into two types: SFC (with slope method) and DFC (with steady-state method). SFC (static flux chamber) type needs only simple equipment and is easy to handle. However, the value of flux might vary with SFC method, because it assumes that the change of concentration in chamber is linear with time. Although more specific equipments are required for DFC (dynamic flux chamber) method, it can lead to a constant result without any ambiguity. We made a self-designed DFC using a small and compact kit, which recorded good sample homogeneity (RSD < 5%) and recovery ( > 90%). Relative expanded measurement uncertainty of this improved DFC method was 7.37%, which mainly came from uncontrolled sweep air. The study shows that the improved DFC method can be used to collect highly reliable emission data from large landfill area.

• Journal of radiological science and technology
• /
• v.40 no.4
• /
• pp.605-611
• /
• 2017

The structure of the actual detector was computed using the code of the PENELOPE. Using the standard mixed sources (450, 1,000 ml), compare the effectiveness of each energy according to various densities and height of the PENELOPE computer simulation, and calculate the effectiveness of the various environmental specimens and apply them to various environmental specimens to determine the lower limit. The values obtained by the obtained value were obtained by applying the obtained efficiency to the actual environmental specimens and obtaining the lower limit values. The density correction factor is 1.155 g of the density correction factor of $0.4g/cm^3$ (59.54keV), 1.153 (661 keV), $1.06g/cm^3$ 1.064 (1,836.04keV), 1.03, and 1.033. It was confirmed that the radioactivity concentration of environmental samples decreased as the amount of specimen was measured increases, and the MDA value decreased as time measured increases.

• Journal of Environmental Impact Assessment
• /
• v.27 no.5
• /
• pp.431-446
• /
• 2018

In this study, chemical characteristics of $PM_{2.5}$ samples collected in an agricultural area in Nonsan of Korea were investigated focusing on of black carbon, 3 inorganic ions and 22 trace elements. It was found that the relative error and relative standard deviation of many trace elements fell below 10%, which indicates good analytical accuracy and precision. The mean values of $PM_{2.5}$ in an agricultural area were exceeded by new Korean air quality standard of March 2018. The concentration of $PM_{2.5}$ was well correlated with those of black carbon and ions. The concentrations of trace elements were in a wide range of seven orders of a magnitude. Based on these $PM_{2.5}$ data sets, a total of 6 sources were identified using PMF (Positive Matrix Factorization; secondary aerosol (34.4%), soil/road dust (20.1%), biomass burning (16.9%), incineration/fuel combustion (13.2%), vehicle exhaust(12.2%), sea-salt (3.17%). Results of our study indicate that it is very important to control illegal burning activities in agricultural area.

• Journal of Environmental Impact Assessment
• /
• v.27 no.5
• /
• pp.405-416
• /
• 2018

In this research, the distribution of Platinum Group Elements (PGEs) at roadside dust in Daejeon, Korea was examined using an ICP-MS (Inductively Coupled Plasma-Mass Spectrometry) technique. For the quality assurance of the determination, method validation based on its accuracy and precision was conducted using SRM (Standard Reference Material). It was found that the relative errors of Pt, Pd, and Rh against each SRM value were -0.7%, -10.0%, and -20.4%, respectively, while relative standard deviations for three elements were less than 10%. The concentrations of Pt, Pd and Rh in roadside dust averaged as $17.4{\pm}9.2{\mu}g/kg$, $283.6{\pm}20.5{\mu}g/kg$, and $7.3{\pm}2.8{\mu}g/kg$, respectively. The concentrations of Pt and Rh have significantly higher distribution patterns in the dust at roadside and underground parking lot than those in soil of the background or other urban area. The correlation analysis between concentrations of PGEs in roadside dust indicates that the distribution of Pt and Rh concentration were strongly affected by automobile sources.

• The Korean Journal of Pesticide Science
• /
• v.18 no.4
• /
• pp.258-268
• /
• 2014

The test method of aerobic transformation in soil has established based on international test guideline (OECD TG 307). And then, the case study was conducted with [$^{14}C$]butachlor. Butachlor is commonly used herbicide in Korea. [$^{14}C$]Butachlor was treatrd $6.83mgKg^{-1}$ in loamy soil. The treated soil was incubated in flow-through system for 60 days. The mass balance of applied radioactivity (AR) ranged from 91.1 to 95.5% and from 93.0% to 97.7% for non-sterile and sterile soils, respectively. In non-sterile soil, the concentration of [$^{14}C$]butachlor was declined from 94.4% AR at 0 day to 8.4% AR at 60 days after treatment. 2-Chloro-2',6'-diethylacetanilide was the major degradation product detected in soil extract. The calculated $DT_{50}$ and $DT_{90}$ of butachlor were 10.4 days and 34.6 days, respectively. $^{14}CO_2$ and non-extractable soil residue were increased up to 3.5% and 43.5% AR at 60 DAT. There is no significant decrease of the [$^{14}C$]butachlor through the incubation period in sterile soil.