• Journal of Soil and Groundwater Environment
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• v.9 no.4
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• pp.15-23
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• 2004

Deicer operations provide traffic safety during winter driving conditions in urban areas. Using large quantities of de-icing chemicals (i.e., $CaCl_2$ and NaCl) can cause serious environmental problems and may change behaviors of heavy metals in roadside sediments, resulting in an increase in mobilization of heavy metals due to complexation of heavy metals with chloride ions. To examine effect of de-icing salt concentration on the leaching behaviors and mobility of heavy metals (cadmium, zinc, copper, lead, arsenic, nickel, chromium, cobalt, manganese, and iron), leaching experiments were conducted on roadside sediments collected from Seoul city using de-icing salt solutions having various concentrations (0.01-5.0M). Results indicate that zinc, copper, and manganese in roadside sediments were easily mobilized, whereas chromium and cobalt remain strongly fixed. The zinc, copper and manganese concentrations measured in the leaching experiments were relatively high. De-icing salts can cause a decrease in partitioning between adsorbed (or precipitated) and dissolved metals, resulting in an increase in concentrations of dissolved metals in salt laden snowmelt. As a result, run-off water quality can be degraded. The de-icing salt applied on the road surface also lead to infiltration and contamination of heavy metal to groundwater.

• Journal of Soil and Groundwater Environment
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• v.11 no.5
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• pp.43-50
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• 2006

Bioreporter bacteria, such as recombinant bioluminescent bacteria, have been used for the detection of specific compounds in complex environmental media. In this study, optimum conditions for the preparation and application of deep-freezed and Iyophilized recombinant bioluminescent strain KG1206 were investigated for the future application on contaminated environmental sites. Genetically engineered microorganism, Pseudomonas putida mt-2 KG1206, contains TOL plasmid and the plasmid inserted $P_{m}$, promoter on the upper part of lux gone in vector pUCD615, and m-toluate and benzoate are considered direct inducers for bioluminescence. Optimum conditions determined for the preparation and application of the deep-freezed and lyophilized strain were followings: cryoprotective agent (24% sucrose), lyophilization time (12 hrs), strain concentration ($OD_{600}=0.6$), reconstitution for freezed strain (quick reconstitution at $35^{\circ}C$), reconstitution for lyophilized strain ($3{\sim}6$ hrs exposure on LB medium), carrying conditions (keep at $20^{\circ}C$ after reconstitution). These results demonstrate the feasibility of deep-freezed or lyophilized state of genetically engineered bioluminescent strain for environmental usage.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.34-34
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• 2012

Heavy storms rainfall has caused many landslides and slope failures especially in the mountainous area of the world. Landslides and slope failures are common geologic hazards and posed serious threats and globally cause billions in monetary losses and thousands of casualies each year so that studies on slope stability and its failure mechanism under rainfall are being increasing attention of these days. Rainfall-induced slope failures are generally caused by the rise in ground water level, and increase in pore water pressures and seepage forces during periods of intense rainfall. The effective stress in the soil will be decreased due to the increased pore pressure, which thus reduces the soil shear strength, eventually resulting in slope failure. During the rainfall, a wetting front goes downward into the slope, resulting in a gradual increase of the water content and a decrease of the negative pore-water pressure. This negative pore-water pressure is referred to as matric suction when referenced to the pore air pressure that contributes to the stability of unsaturated soil slopes. Therefore, the importance is the study of saturated unsaturated soil behaviors in evaluation of slope stability under heavy rainfall condition. In an actual field, a series of failures may occur in a slope due to a rainfall event. So, this study attempts to develop a numerical model to investigate this failure mechanism. A two-dimensional seepage flow model coupled with a one-dimensional surface flow and erosion/deposition model is used for seepage analysis. It is necessary to identify either there is surface runoff produced or not in a soil slope during a rainfall event, while analyzing the seepage and stability of such slopes. Runoff produced by rainfall may result erosion/deposition process on the surface of the slope. The depth of runoff has vital role in the seepage process within the soil domain so that surface flow and erosion/deposition model computes the surface water head of the runoff produced by the rainfall, and erosion/deposition on the surface of the model slope. Pore water pressure and moisture content data obtained by the seepage flow model are then used to analyze the stability of the slope. Spencer method of slope stability analysis is incorporated into dynamic programming to locate the critical slip surface of a general slope.

• Korean Journal of Medicinal Crop Science
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• v.4 no.1
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• pp.19-26
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• 1996

The crop rotation of rice and ginseng in paddy field has very important meaning because up-land field suitable for ginseng cultivation is now being insufficient day by day in main ginseng production area. This studies were conducted to define basic problems related to ginseng cultivation and replanting in paddy field. In Keumsan district, the most serious problem on ginseng cultivation in paddy field was excess of mineral salts left behind in the soil of rice cultivation. The amounts of organic matters, CEC and the mineral elements including potassium were higher in the soil of paddy ginseng field compared to those of upland. Plant growth of 3 and 4 year old ginseng and root yield of four year old ginseng cultivated in paddy field of 1st and replanting were not decreased compared to those of 1st - planting of up-land field, but those were significantly decreased in replanted compared to those of first planted upland field. Crop rotation with ginseng and rice in paddy field seemed to be a good way to avoid hazards of continuous cropping of ginseng with it's outyield of root and less infection of diseases. Amounts of crude saponin and ginsenosides of ginseng cultivated in paddy field were not differ from those of upland field.

• Journal of Trauma and Injury
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• v.20 no.1
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• pp.33-39
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• 2007

Purpose: Few studies have been done for spinal injuries after skiing and snowboarding accidents. Assuming that the riding patterns of skiing and snowboarding were different, we analyzed the differences between the mechanisms, diagnoses and levels of spinal injuries caused by them. The purpose of this study was to gain a better understanding of spinal hazards associated with skiing and snowboarding in order to educate skiers and snowboarders. Methods: We conducted a prospective study of 96 patients who had sustained spinal injuries as a result of skiing and snowboarding accidents from January 2003 to March 2006. We used a questionnaire, radiological studies, history taking, and physical examinations. We analyzed the mechanism of injury, the level of spinal injury, the severity of spinal injury, and the Abbreviated Injury Scale scores (AIS score). We used the t-test and the chi-square test. Results: The skiing and the snowboarding injury group included in 96 patients. The skiing injury group included 30 patients (31.2%), and the snowboarding injury group included the remaining 66 patients (69.8%). The primary mechanism of injury in skiing was collisions and in snowboarding was slip downs (p=0.508). The primary level of spinal injury in skiing and snowboarding was at the L-spine level (p=0.547). The most common athlete ability of the injured person was at the intermediate level (p=0.954). The injured were most commonly at the beginner or the intermediate level (p=0.302). The primary diagnosis of spinal injury in skiing and snowboarding was back spain (p=0.686). The AIS scores did not differed between the two groups (p=0.986). Conclusion: The most common spinal injury after skiing and snowboarding accidents was back sprain. There was no difference in the severity of spinal injury between skiing and snowboarding accidents.

• Journal of Korean Society of Transportation
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• v.26 no.4
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• pp.99-110
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• 2008

It is commonly estimated that there is a much higher potential for accidents at a crossroads than along a single road due to its plethora of conflicting points. According to the 2006 figures by the National Police Agency, the number of traffic accidents at crossroads is greatly increasing compared to that along single roads. Among others, crossroads installed with traffic signals have more varied influential factors for traffic accidents and leave much more room for improvement than ones without traffic signals; thus, it is expected that a noticeable effect could be achieved in safety if proper counter-measures against the hazards at a crossroads were taken together with an estimate of causes for accidents This research managed to develop models for accident forecasts and accident intensity by applying data on accident history and site inspection of crossroads, targeting four selected downtown crossroads installed with traffic signals. The research was done by roughly dividing the process into four stages: first, analyze the accident model examined before; second, select variables affecting traffic accidents; third, develop a model for traffic accident forecasting by using a statistics-based methodology; and fourth, carry out the verification process of the models.

• Journal of the Korean Vacuum Society
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• v.19 no.6
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• pp.442-452
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• 2010

Our team carried out a new program for public engagement on nanotechnology in Korea. We chose 22 monitors, who majored in science or technology and graduated from universities long time ago. Most of them were married and housewives. This 'focus group' had not only general knowledge about science or technology but also much interest in social activities. The 167 nanoproducts to be monitored were for daily life, e.g. home appliances (washing machine, refrigerator, water purifier, etc), clothing, cosmetics, food, toy, and others. And the period of it was one month. The monitors had a sheet with 10 questions, and filled them out in essay form. All of them submitted 2~3 sheets every weekend to our team. Before monitoring, our team had a meeting for introduction and explanation about the potential risk of nanotechnology as well as benefits from it. Another meeting was held after finishing monitoring to share their experience one another. The main results of the monitoring were as follows: the number of nanoproducts describing both the definition of 'nano' and the size of nanomaterials was just 2 (1.2%) the number of them explaining the technical methods enough was 15 (9/0%) the number of them accounting for the reason of functional improvement enough was 14(8.4%); the number of them doubtful as if there would be exaggeration or false knowledge was 27 (16.2%); the number of them commenting potential hazards to human health or environment was almost zero; the number of them describing about safety certification acceptable was 9 (5.4%). The monitors made a proposal containing recommendation to Government and industry. The contents were as follows: industry should make the manual in detail and correctly, Describe Certificate detailed and correctly, Do research on risk and toxicity continually, Educate employee about nanoproducts at consumer's center; Government should make indication of nanoproducts compulsory, Appoint Certificate Authority and make Certificate Mark guaranteeing the safety on nanoproducts, Make detailed explanation about nanoproducts compulsory.

• Journal of Veterinary Clinics
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• v.32 no.6
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• pp.504-507
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• 2015

Coxiella burnetii is an obligate intracellular rickettsial organism and the causative agent of Query fever, a zoonosis that occurs worldwide. In Korea, C. burnetii infection had occurred in humans and animals. However, the studies were only conducted in geographically limited area for detection of C. burnetii. The objective of this study was to detect C. burnetii in Korean native cattle and dairy cattle nationwide by real-time PCR. The total of 807 blood samples from 622 Korean native cattle and 185 dairy cows, 170 individual milk samples of dairy cows, and 348 bulk tank milk samples of dairy herds were collected nationwide. From blood samples, C. burnetii was detected in 17 (2.7%) out of 622 Korean native cattle and 2 (1.1%) of 185 dairy cows. From milk samples, C. burnetii was detected in 27 (15.9%) out of 170 individual milk samples of dairy cows. And C. burnetii was detected in 84 (24.1%) of 348 bulk tank milk samples. In conclusion, this study revealed that the detection rates are considerably high in cattle and the infection of C. burnetii has been continuously occurring in cattle of Korea. In order to prevent the hazards of a zoonosis Q-fever that occur both humans and domestic animals, further studies are needed to clarify the epidemiology of Q-fever of domestic animals and humans in Korea.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.2
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• pp.100-106
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• 2012

Objectives: Diazinon is an insecticide which acts as a contact stomach and respiratory poison, and used throughout the world to control a wide range of sucking and chewing insects and mites on a range of crops. In this study, the airborne diazinon levels were measured for farmers, pest control operaters, landscapers, and agricultural chemicals sellers, and an assessment of the health risk to the workers was presented. The exposure scenario was based on the route of inhalation and skin absorption. The "OSHA Method No. 62" was used to sample and measure the airborne diazinon levels. The skin wipe method was applied to measure the level of the diazinone exposure through the skin. For the determination of exposure scenario, the exposure factors were surveyed for the daily average inhalation rate and the exposure period and frequency and time of diazinone as well as the body weight and lifetime of the workers. The median values of exposure frequency and exposure time were selected after evaluating the validity of those. Methods: The highest level of the diazinon exposure in the air was $107.21ug/m^3$ in farmers, followed by $93.53ug/m^3$ in landscapers, at $31.40ug/m^3$ in pest control operators, and $1.04ug/m^3$ in agricultural chemical seller. The amount of skin absorption was the highest in farmers at 63.39 ug/day, followed by landscapers at 10.47 ng/day, pest control operaters at 4.26 ng/day, and agricultural chemicals sellers at 0.34 ng/day. The hazardous indices calculated using toxicological reference value were 2.79 for pest control operaters, 0.41 for landscapers, 0.07 for agricultural chemicals sellers, and 0.06 for farmers. Conclusions: While the farmers were exposed to the high levels of diazinon through the air and skin, the pest control operaters, landscapers and agricultural chemicals sellers have more the diazinon hazards than the farmer based on the risk assessment in this study.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.28 no.3
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• pp.257-266
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• 2018

Objectives: The objective of this study was to evaluate asphalt fumes and PAHs exposure among asphalt road paving workers. Methods: Task-based personal air samplings(n=41) were carried out in 3 asphalt road paving construction sites using PTFE (polytetrafluorethylene) filters for asphalt fume and XAD-2 with glass fiber filters for PAHs. The concentration of fumes and PAHs were showed by four different job(paver finisher operator, paving laborer(raker), macadam roller operator and tire roller operator). Results: The geometric mean(GM) concentration of asphalt fumes as benzene soluble aerosol was highest at paving laborers($42.32{\mu}g/m^3$), followed by in order, paver finisher operators($41.57{\mu}g/m^3$), macadam roller operators($31.9{\mu}g/m^3$), and tire roller operators($30.31{\mu}g/m^3$). The GM of total PAHs concentration was highest at paver finisher operators($37.5{\mu}g/m^3$), followed by in order, paving laborers($20.13{\mu}g/m^3$), tire roller operators($8.66{\mu}g/m^3$), and macadam roller operators($6.23{\mu}g/m^3$). The results of the evaluation of 16 compounds of PAHs showed that the concentrations of naphthalene, achenaphthylene, achenaphthene, pyrene, fluorene and benz (a) anthracene was higher than those of other PAHs compounds and as the carcinogenic substances, benzo(a)pyrene, and debenz(a,h) anthracene were detected. The benzo(a)pyrene equivalent concentration(BaPeq) was $2.81{\mu}g/m^3$ at paver finisher operators, $2.07{\mu}g/m^3$ at paving laborers, $0.41{\mu}g/m^3$ at tire roller operators and $0.22{\mu}g/m^3$ at macadam roller operators. Asphalt road paving workers have higher benzo(a)pyrene equivalent(BaPeq) values even though at lower total PAHs concentration than workers in steel pipe coating and tar industry. Conclusions: Asphalt road paving workers were found to have risk of carcinogen exposure due to higher Benzo(a)pyrene equivalent concentration(BaPeq) than other PAHs exposure occupations. This study confirmed the carcinogenic hazards among asphalt paving workers.