• Journal of People, Plants, and Environment
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• v.23 no.6
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• pp.625-636
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• 2020

Background and objects: Soil contamination caused by CaCl₂ that is used to deice slippery roads in winter is now recognized as one of the major causes of damage of roadside plants. The aim of this study is to identify the salt mitigation effects of planting Chrysanthemum zawadskii and using a soil conditioner. Methods: The study was conducted at the site where Pinus densiflora f. multicaulis was planted on the roadside between Konkuk University Sageori and Danwol Samgeori located in Chungju-si. We classified the soils collected from the field experimental site according to the degree of the damage caused by deicing agents and divided the site into six blocks of three 80 × 80 cm plots replicated by treatment type. Three selected plots were treated with loess-balls on the soil surface (high salinity with loess-balls, medium salinity with loess-balls, low salinity with loess-balls) and three were left as an untreated control (H = high salinity, M = medium salinity, L = low salinity). The soil properties were measured including pH, EC and exchangeable cations as well as the growth of Chrysanthemum zawadskiia. Results: In the results of soil analysis, pH before planting Chrysanthemum zawadskiia was 6.39-6.74 and in September, five months after planting, the acidity was reduced to 5.43-5.89. Electrical conductivity (EC) was measured to be H > M > L with the higher degree of damage by deicing agents. The analysis of deicing exchangeable cations showed that the content of Ca²⁺ of soils were significantly correlated to deicing exchangeable cations (Ca²⁺, Na⁺, Mg²⁺) in the shoot part of Chrysanthemum zawadskii. The loess-ball treatment showed a lower content of deicing exchangeable cations than the treatment where Chrysanthemum zawadskiia was planted. Conclusion: In this study, the use of a new system made of loess-balls is proposed as a soil conditioner to protect soils from the adverse effects of road deicing salts. These data suggest that treatment of soil conditioners and planting Chrysanthemum zawadskiia are effective in mitigation of salt stress on the soils damaged by deicing agents.

• The Journal of Korean Society for Radiation Therapy
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• v.21 no.2
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• pp.75-82
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• 2009

Purpose: Measure the ozone level in the treatment room while treating a patient so want to know the degree of contamination caused by ozone occurrence. Materials and Methods: Use the linear accelerator (Clinac 21EX, Varian, USA) with the ozone meter (series-200, aeroQual, New Zealand) and water phantom (Wellhofer, IBA, Germany) is irradiated the radiation so that measured the ozone generation level according to MU, dose-rate, SSD, field size, energy, delay time and put the ozone meter in the treatment room actually while treating a patient so measured the daily ozone level variation. Results: While irradiating the radiation, degree of ozone contamination wasn't affected by the energy but mostly in case of electron beam, ozone level was higher than photon beam. The higher dose-rate (0.016~0.025 ppm/hr), the farther SSD (0.018~0.030 ppm/hr), the wider field sizes (0.016~0.025 ppm/hr), the more MU (0.018~0.046 ppm/hr), it occurred high ozone level. Ozone decrement according to delay time changed the background level (0.016 ppm/hr) after elapsed time of 10 minutes from irradiating radiation. And daily ozone occurrence level in the treatment room was below ozone standard level 0.1 ppm/hr (average:0.06 ppm/8 hr) but it could confirm that ozone generation level was included the level (max:0.038 ppm/hr) above 0.02 ppm/hr which patient could perceive. Conclusion: Through ozone level according to variation of certain conditions, actually in the treatment room ozone generation level didn't damaged to patients or workers. Commonly peoples think that ozone was harmful gas but it thought that small amount of ozone generation level while treating a patient was beneficial in the treatment room through air purge action of pathogenic germ or virus sterilization.

• Journal of the korean academy of Pediatric Dentistry
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• v.43 no.4
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• pp.365-373
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• 2016

Composites are the most useful restorative material. However, composites have some disadvantages such as polymerization shrinkage, long working time, and susceptibility to water and contamination, which are stood out more especially when treating children. To solve these problems, bulk-fill composites have been developed. The aim of this study is to compare mechanical properties of bulk-fill and conventional composites. Bulk-fill composites (SureFil SDR flow (SDR), Tetric N-Ceram bulk fill (TBF)) and conventional composites (Filtek Z-350 (Z-350), Unifil Flow (UF), Unifil Loflo Plus (UL)) were used. The Vickers hardness tester was used to measure the microhardness of materials, and Fourier transform infrared spectroscopy was used to measure the degree of conversion. Polymerization shrinkage was measured by using a linometer. Flexural and compressive properties were measured by using the universal testing machine. Data were statistically analyzed by ANOVA and Scheffe's post hoc test. The level of significance was set to p < 0.05. Most conventional composites showed higher microhardness than bulk-fill composites. However, bulk-fill composites showed a higher top/bottom microhardness ratio than conventional composites. Bulk-fill composites showed a higher top/bottom degree of conversion ratio than conventional composites. The polymerization shrinkage was highest in UL and lowest in Z-350. The polymerization shrinkage of flowable composites was higher than that of non flowable composites. The compressive properties were highest in Z-350 and lowest in SDR and UL. In terms of flexural properties, Z-350 was the highest. However, none of the bulk-fill composites exhibited mechanical properties as good as those of conventional composites. Nonetheless, the ratio of microhardness and degree of conversion, which are important properties of bulk filling, were higher in bulk-fill composites. Therefore, the bulk-fill composites might be considered suitable restorative materials in pediatric dentistry.

• Journal of Soil and Groundwater Environment
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• v.10 no.3
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• pp.32-37
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• 2005

The soil properties of the royal tombs (managed by cultural properties administration) located in Seoul and suburban Gyonggi area were investigated to see the influence of the change in soil environment on the royal tomb s이I. To compare the soil chemical properties of four royal tombs soil of Changdeokgung, Jongmyo, Seooneung, and Dongguneung, pH, organic content, available phosphate, extractable calcium, extractable potassium, extractable magnesium, cation exchange capacity, degree of base saturation, and total nitrogen content were measured. The concentrations of Cd, Pb, and Cu measured as the degree of heavy metal contamination can be an indication of atmospheric pollution in the soil environment. To estimate the degree of soil compaction, soil hardness, pore space, porosity, bulk density, and soil atmosphere were analyzed. Through these studies, following conclusions were made: 1. The soil hardness and pore space which can be used as indexes of soil compaction, were worse in the soil of Seooneung than in those of Changdeokgung and Dongguneury. These phenomena seem to be the result of increase in visitors in Seooneung and Dongguneung better and soil management in Changdeokgung and Dongguneung. When three different regions of forest area, prohibited area, and soil compaction area in Seooneung soil were compared, the degree of compaction in the forest area was less than compaction area, indicating the need for the employment of soil resting period in the compaction area. 2. The pH measurements of all four royal tombs soil were higher in top soil than sub soil. The higher soil pH values in Jongmyo and Seooneung seem to result from the application of soil conditioner. In the case of Seooneung, the values for soil pH and organic content were higher in the forest area than those in compaction area. It is thought that active soil management was employed in the forest area through application of organic matters and soil conditioners. 3. The heavy metal contents from soil of Changdeokgung and Jongmyo were higher than that from soil of Dongguneung. Since Changdeokgung and Jongmyo are located inside Seoul, it is thought that the high level of heavy metal concentrations in these royal tomb soil is the result of accumulation of pollutants from the city.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.1
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• pp.66-74
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• 2005

This survey was conducted to assess the consumer perceptions of food-related hazard in 500 housewives from all over Korea. The subjects were selected by stratified random sampling method. The survey was performed using structured questionnaire through telephone interview by skilled interviewers. The results showed that 34.6% of the respondents felt secure and were not concerned about food safety, and 65.4% were concerned about food safety. Logistic regression analysis showed that the increasing concern on food brands, food additives (such as food preservatives and artificial color), and imported foodstuffs indicated the current increasing concern on food safety. Other related factors indicating the increasing concern on food safety were education level and care for children's health. The respondents who cared about food safety expressed a high degree of concern on processed foodstuffs such as commercial boxed lunch (93.3%), imported foods (92.7%), fastfoods (89.9%), processed meat products (88.7%), dining out (85.6%), cannery and frozen foods (83.5%), and instant foods (82.0%). The lowest degree of concern was on rice. All the respondents perceived that residues of chemical substances such as pesticides and food additives, and endocrine disrupters were the most potential food risk factors, followed by food-borne pathogens, and GMOs (Genetically Modified Organisms). However, these results were not consistent with scientific judgment. Therefore, more education and information were needed for consumers' awareness of facts and myths about food safety. In addition, the results showed that consumers put lower trust in food products information such as food labels, cultivation methods (organic or not), quality labels, and the place of origin. Nevertheless, the respondents expressed their desire to overcome alienation, and recognized the importance of knowing of the origin or the producers of food. They identified that people who need to take extreme precautions on food contamination were the producers, government officials, food companies, consumers, the consumer's association, and marketers, arranged in the order of highest to lowest. They also believed that the production stage of agriculture was the most important step for improving the level of food safety Therefore, the results indicated that there is a need to introduce safety systems in the production of agricultural products, as follows: Good Agricultural Practice (GAP), Hazard Analysis and Critical Control Point (HACCP), and Traceability System (75).

• Journal of the Korean Society of Groundwater Environment
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• v.4 no.1
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• pp.41-53
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• 1997

Geochemical data of soil and water samples were presented in order to assess the environmental impart for drinking water sites. Microscopic observation of rock samples and physical and chemical analysis of soil and water samples were undertaken. The geology of study areas are classified into three groups such as granitic rocks, meta-sedimentary rocks and sedimentary rocks. Enrichment of heavy metals derived from those rocks is not found in this study areas. Soils were analyzed for Cu, Pb, Zn, Cd and Cr using AAS extracted by HNO$_3$+HClO$_4$ and 0.1 N HCl. Heavy metal concentrations in soils are within the range of those in uncontaminated soils. In comparison of metal contents extracted by 0.1 N HCl and HNO$_3$+HC1O$_4$, less than 10% of the heavy metals are present in the exchangeable fraction. In particular, an pollution index has been proposed to assess the degree of soil contamination. Pollution index in soils are between 0.03 and 0.47 therefore, soils are not polluted with heavy metals. Deep groundwaters within granitic rocks have been evolved into Na$\^$＋/-HCO$_3$$\^$-/ type, whereas other deep groundwaters evolved into Ca$\^$2＋/-HCO$_3$$\^$-/ type. The predominance of Na$\^$＋/ over Ca$\^$2＋/ in deep groundwaters within granitic rocks is a result of dissolution of plagioclase, but for sedimentary and meta-sedimentary rocks, dissolution of calcite is a dominant factor for their hydrogeochemistry. The pH, conductivity and contents of the most dissolved ions in the water increase with depth. Shallow groundwaters, however, are highly susceptible to pollution owing to agricultural activities, considering the fact that high contents of nitrate, chloride and potassium, and high K/Na ratio are observed in some shallow groundwaters. In a thermodynamic approach, most natural water samples are plotted within the stability fields of kaolinite and smectite. Therefore, microcline and other feldspars will alter to form clay minerals, such as kaolinite and smectite. From the modelling for water-rock interactions based on mass balance equation, models accord well with behavior of the ions and results of thermodynamic studies are derived.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.10
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• pp.1497-1507
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• 2016

The purpose of this study was to conduct importance and performance analysis of sanitation management in workers at small and medium foodservice industries using HACCP prerequisites. Questionnaires were distributed to 500 small and medium foodservice industry workers in Seoul Gyeonggi province, and a total of 458 responses were used for analysis. Factors with relatively low comparison degree were as follows. 'Handwashing and clean uniform of employee in the workplace', 'regular checking and managing of trapped vermin and rodents', 'checking stocked raw materials', 'recording and filing the results of improved food safety factors', and 'regular cleaning and sterilizing of monitoring tools' factors must be improved along with their performance levels through sanitation education. According to the IPA results, among the 15 HACCP prerequisite factors with high importance but low performance were '2. Regular checking and managing of trapped vermin and rodents', '4. Handwashing and clean uniform of employee in the workplace', '14. Preventing food cross-contamination'. Furthermore, the small and medium foodservice industry IPA with high importance but low performance were 'Regular checking and managing of trapped vermin and rodents', 'Handwashing and clean uniform of employee in the workplace', and 'Preventing food cross-contamination' for the small foodservice industry, along with 'Vermin and rodents control' and 'Recording and filing the results of improved food safety factors' for the medium foodservice industry. Thus, there is a need for reinforced hygiene education through case studies on actual food service establishments to fulfill sanitation guidelines and set amended guides for much-needed items for small and mid-sized food service.

• Microbiology and Biotechnology Letters
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• v.8 no.3
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• pp.155-166
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• 1980

Studies have teen undertaken to investigate the degree of microbial contamination in the subsidiary materials which have been known as an important source of microorganisms associated with spoilage of fish sausage and fish paste products. Twenty hinds of food ingredients including starch, spices and condiments, 59 samples in total collected from commercial fish sausage processing plants and supermarket in the period of July to October 1979, were examined for standard plate count, coliform and fecal coliform, mold and yeast, thermoduric microorganisms, aerobic sporeformers (mesophilic and thermophilic), anaerobic sporeformers (mesophilic and thermophilic) and sulfide spoilage anaerobes. The results obtained are summarized as follows. 1. Among the food ingredients examined, corn starch, black pepper, hot pepper, onion, garlic, ginger, beef extract and frank marked high bacterial contamination with general and sporeforming microorganisms. And bacterial content of marked samples were generally higher than that of the samples from plants. 2. The high standard plate count caused by high content of these bacteria like thermoduric, mesophilic or thermophilic sporeforming aerobes. 3. Bacterial content of food ingredients such as black pepper and beef extract being used in plants, and black pepper, hot pepper, onion and garlic from the market were exceeded the bacterial standards being enforced in Japan and U. S. A. 4. Average standard plate count was in the range of 10$^4$to 10$^{5}$ /g for black pepper, wheat flour, onion and garlic collected from plants, and 10$^{5}$ to 10$^{7}$ /g for black pepper, hot pepper, onion and garlic from market. No plate count was observed in pepper essence and coloring material. 5. Coliform organism was detected in starch, black pepper, hot pepper, onion, garlic, ginger and gluten that showed high standard plate but no fecal coliform in the samples except black pepper and hot pepper. 6. Average mold and yeast count was 140 to 460/g for corn starch, wheat flour and black pepper from plants, and 10$^3$/g for black pepper and hot pepper from market. No count was observed in the other ingredients. 7. Sulfide spoilage sporeforming anaerobes boiled for 5 min. at 10$0^{\circ}C$ and incubated at 55$^{\circ}C$ was not detected in all the samples examined.

• Korean Journal of Environmental Agriculture
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• v.12 no.2
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• pp.129-143
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• 1993

The objective of this study is to understand the status of the water pollution in rural areas and to furnish a basic material for the management of the water pollution in rural areas. For this purpose, the Bokha river basin, Ichon-Gun, Kyungki-Do considering as a typical agricultural area was selected as a representative experimental watershed. The characteristics of water pollution in streams of the Bokha river basin was revealed by investigating and analyzing data collected for the source of pollution, water qualities in reaches of the stream, the degree of contribution to the river contamination by pollution mass produced from each source, and the status of the self-purification at the main stream. The most important source of the water pollution in investigated watershed was livestock, and the next important one were in the order of population, land use, and industry. The water quality of the Bokha river was relatively favorable judging from the BOD and COD concentration, however since the concentration of T-N and T-P showed significantly large values, it was concluded that the river was seriously contaminated by the nutrient material. The main cause of the river contamination was proved due to livestock waste. For the T-N, both land use and livestock were much more contributied to the pollution than any other source, which characterized the typical water pollution of rural areas. Run-off ratios for the Bokha river tributaries to the main stream were changed according to the similar trend to the variation of discharges in the branch streams. For the value of the self-purification constant at the main stream, it showed smaller value in the downstream reach than the middle-stream and upstream reaches, where could possibly have smaller reoxidation action due to slower velocity and deeper water depth.

• Journal of dental hygiene science
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• v.4 no.1
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• pp.7-11
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• 2004

The purpose of this study was to investigate the distribution of microorganisms and the degree of contamination in the air of the dental clinics and to offer basic data as to the contamination of medical equipment and the prevention of the clinics. With this in mind, the researcher gathered air samples from the waiting rooms and medical offices of nine dental clinics in the city of J, South Korea with the use of a method of natural inattention and an air sampler and cultivated the samples on the plain table and drew from it bacteria falling and separated and sorted out the colony with the help of ATB and detected the distribution of the germs. The results are following, The number of bacteria falling in the air of the dental clinics was less than 10(CFU/Plate) with the exception of one dental clinic. This implies that they fit in with standards for hygiene. The number of bacteria falling in the air of the medical offices was less than 10(CFU/Plate) with the exception of one dental clinic. This implies that they fit in with standards for hygiene. The survey on the detection of staph. aureus reveals that all the dental clinics with the exception of B dental clinic proving to be positive had non-pathogenic staphylococci detected. The survey on the detection of pathogenic gram negative bacilli indicates that all the dental clinics but one were none detected. The survey on the distribution of germs shows that germs in 7 out of 9 dental clinics were none detected, and that they in four out of 9 waiting rooms were none detected. All the germs detected in the others were mostly non-pathogenic. The study shows that all the subject dental clinics but one were hygienically controlled and that there was a difference in accordance with cleaning and sterilization. This means that dental clinics should be equipped with systematic programs for cleaning and sterilization designed to prevent infection.