• Journal of Korean Society for Atmospheric Environment
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• v.25 no.6
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• pp.523-538
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• 2009

Recently, there has been a keen demand for real-time automatic monitoring of VOCs not only in Korea but other developed countries. We carried out this study to evaluate and to optimize the performance of a continuous automatic monitoring system for hazardous VOCs (HVOCs) in the ambient atmosphere, using an on-line GC system. The online system normally consisted of a Nafion dryer prior to a cold trap of an automatic thermal desorption apparatus and a GC system equipped with two detectors, i.e. PID and ECD. Preliminary tests conducted to check out any contamination of the system revealed an evidence of significant artifact formation of benzene, and it was found that the Nafion dryer (even brand new one) is the source of the benzene artifact. Thus, all the subsequent experiments in this study was carried out inevitably by removing the Nafion dryer. The on-line GC method was investigated with a variety of QC/QA performance criteria such as repeatability, linearity, lower detection limits, and accuracy. In order to find out the best operating condition for the on-line GC system, three different types (in terms of adsorption strength) of cold trap combinations were tested, i.e. (i) Tenax-TA and Carbopack-B combination (weak and hydrophobic); (ii) Tenax-TA, Carbopack-X and Carboxen-1000 combination (strong and hydrophilic); and (iii) Tenax-TA and Carbopack-X combination (medium and hydrophobic/hydrophilic). The USEPA TO-17 manual method was selected as a reference method to evaluate the performance of the on-line method. A series of experiments revealed that the system performance was superior to others when a cold trap packed with hydrophilic adsorbents (Tenax-TA/Carbopack-X/Carboxen-1000 combination) was used and operated at $25^{\circ}C$. However, the system with a cold trap packed with a combination of Tenax-TA and Carbopack-X is more recommended for field applications since the carboxen-1000 adsorbent is too sensitive to water vapor, and hence the performance of the system might be very unstable to humid samples or during rainy days. Furthermore, the precision and accuracy criteria of the Tenax-TA/ Carbopack-X combination were generally compatible with the triple adsorbents cold trap. The continuous automatic monitoring method is, thus, considered very useful to real-time monitoring to understand the variations of VOCs concentrations in ambient air, as it adopts much simpler procedures in sampling, analysis, and data integration steps than manual monitoring methods. However, it should be noted that there is a high possibility of benzene artifacts formation through the Nafion dryer, which is often installed to remove water vapor in air samples before being adsorbed onto the cold trap. Therefore, if a Nafion dryer is used in any studies of monitoring VOCs, the benzene contamination should be carefully examined before carrying out obtaining the data.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2515-2519
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• 2015

Purpose: To determine knowledge levels of working and student nurses about cervical cancer and prophylactic cancer vaccines. Materials and Methods: This study was performed on 259 nursing students in the Department of Nursing and 137 nurses working in Health Research and Practice Center, approved to participate in the study between April-June 2012. The study was performed universally without selecting a sample. A questionnaire that was prepared for evaluating participants' knowledge and attitudes about human papilloma virus (HPV) vaccine was distributed to the nurses and data obtained from the forms were transferred to SPSS 15.00 program and statistically analyzed. Results: It was found that 54.8% of the student nurses were between 21-24 years old and 13.1% of working students were between 25-28 years old. When student nurses and working nurses were compared in terms of their knowledge about the causes of cervical cancer, their ideas about prevention from cervical cancer with HPV vaccine, their ideas about possible risks of HPV vaccine and conservation ratios of HPV vaccine, it was observed that there were no statistically significant differences (p>0.05). When student nurses and working nurses were compared in terms of the information-source about HPV, ways of HPV contamination, awareness about people who are susceptible to HPV contamination and age of HPV vaccination, it was determined that there was a statistically significant difference (p<0.05). Conclusions: It was found that all nurses had some knowledge about cervical cancer and HPV vaccine, but this was not sufficient. Therefore; it is recommended to use verbal, written and visual communication tools intensively in order to have topics on cervical cancer, early diagnosis and prevention in bachelor and master programs for nurses, to inform society about cervical cancer and HPV vaccine for public health and to teach precautions for its prevention.

• Journal of the Korean earth science society
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• v.24 no.8
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• pp.711-720
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• 2003

To study characteristics of the heavy metal pollution, sediment samples were collected at 67 sites on the roadside of Jeonju city during summer and winter, 2002. The total concentration of metals including Cd, Co, Cr, Cu, Ni, Pb, Zn, and Mn in the sediment samples were determined. The results indicate that the roadside sediments in Jeonju city have lower (1/2 to 1/7 times) concentrations of Zn, Cu, Pb and Cd than the metal concentrations previously reported for roadside soil, dust and sewage sludges in Seoul. However, the metal concentrations are higher than environmental quality criteria in soil suggested from several countries, and Zn, Cu, Pb and Cd contents are usually 2-7 times higher than the world average contents of the metals in natural soil. Although pollution index and concentrations of Cr, Ni, Pb and Zn in the roadside sediments at industrial area were usually higher than those of downtown and residential area, the metal having small vehicle- and steel-related industries had high concentrations of metals. The results of chemical partitioning analysis showed that Pb, Zn and Mn are mainly associated with carbonate/adsorbed and Fe-Mn oxide phases but that Cu is largely associated with the organic and sulfide fractions. It thus indicates that both large and small (vehicle- and steel-related) industries are main sources of heavy metal contamination. Due to high solubility of the carbonate phases by natural leaching episodes, the carbonate/adsorbed Cd, Co, Ni, Pb, Zn and Mn in the roadside sediments may serve as a potential source of contamination.

• Journal of the Korean Dietetic Association
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• v.4 no.2
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• pp.235-244
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• 1998

Hand washing is an important component of hygiene program for food handlers. Hands can be a source of direct or indirect contamination of foods with pathogenic microorganisms. In this study, the effectiveness of hand washing methods and the use of 70% alcohol solution against transient skin bacteria was tested in an university foodservice facility. 70% alcohol solution is sprayed for 5 seconds automatically when hands are placed in the dispenser. Samples were taken using swab technique in meat cutting area, vegetable trimming area, and vegetable cutting area: before and after washing hands according to planned methods, and after being sprayed with 70% alcohol solution after washing hands. The bacteriological analysis of total plate counts, coliform, fecal coliform of food handlers' hands was done. Statistical data analysis was completed with Mann-Whitney U test and Kruskal-Wallis model using the SPSS program. The levels of initial contamination of workers' hand were significantly different by the work areas($x^2$=9.156, p<0.01). Workers in the vegetable trimming area had more heavily soiled hands than in the other work areas. Mean of TPC counts and coliform was 8.97×$10^5$ CFU/12.4$cm^2$, 2.93×$10^2$ MPN/12.4$cm^2$ respectively, but fecal coliform was not detected. Transient bacteria were removed from hands after washing and using 70% alcohol solution but were not removed completely. Mean reduction percentage in TPC varied among work areas and ranged from 93.19% to 94.99%, and in coliforms from 97.31% to 100%. A significant difference in TPC was found between before and after hand disinfection (Z=-2.714, p<.01) and between standardized hand washing procedures and un-standardized hand washing procedures(z=-2.301, p<.01). Subjects using the hand sanitizer showed a great elimination of TPC(99.45% reduction), but this effect was valid only after following proper washing procedures. Based on the results, the most effective hand washing method was recommended as the combination of the standardized hand washing procedure with warm-water and use of the 70% alcohol solution. The results can be used to develop hand hygiene programs and training strategies for enhancing hand hygiene practices for food handlers in foodservice operations.

• Economic and Environmental Geology
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• v.30 no.1
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• pp.61-65
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• 1997

Cadmium occurs as a minor element in sphalerite ((Zn, Fe)S) from the Boseong-Jangheung gold-silver mine district. We analyzed the abundance of cadmium in sphalerite using an electron probe micro analyzer (EPMA) and discussed the natural sources of cadmium in terms of bedrock geochemistry, in order to preliminarily reconnoiter the potential cadmium contamination in mine districts. Cadmium contents of sphalerites from the Au-Ag mines (Bodeok, Mundeok, Jeonbo, Boknae, Keumsan) in the Boseong-Jangheung district are considerably high, compared with cadmium contents of sphalerites (average = 0.5 wt.% Cd, maximum = 4.4 wt.% Cd) in the world. Sphalerites from the Keumsan mine (average = 9.49 wt.% Cd, maximum=11.22 wt. Cd) are highly enriched in cadmium. Our data suggest that the Boseong-Jangheung area is an important potential site of cadmium contamination in Korea. Based on bedrock geochemistry, natural causes of cadmium enrichment in sphalerite from the mine district are thought to be the mixing of cadmium leached from organic-rich, metasedimentary rocks (including coal) and/or black shales. From this study, we propose that the pinpointing of potential sites of pollution by toxic heavy metals can be done effectively through detailed reconnaisance study on mineralogical compositions of ore minerals such as sphalerite from the mine area.

• Journal of Dairy Science and Biotechnology
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• v.27 no.1
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• pp.1-12
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• 2009

In 2008, baby formula containing melamine was found to be responsible for a large outbreak of renal failure in infants in China. A total of 294,000 infants were hospitalized, and at least 6 babies died due to ingestion of the tainted formula. Melamine contains high levels of nitrogen (>60%), which is used as an indicator of protein content. Therefore, high levels of melamine in infant formula were thought to be the result of deliberate contamination m an attempt to increase its apparent protein content. Following inspections by China's national inspection agency, assorted products from at least 22 dairy manufacturers across China were found to have varied levels of melamine (range: 0.096196.61 mg/kg). Melamine co-exposure with cyanuric acid can induce acute melamine-cyanurate crystal nephropathy, which can lead to renal failure at much lower doses than if either compound were ingested alone. However, currently, there are very few data on melamine analogues other than cyanuric acid. At an expert meeting of the WHO and FAO held to review toxicological aspects of melamine and cyanuric acid on December 14, 2008, a new tolerable daily intake (TDI) of melamine was established that could be applied to the entire population, including infants. Therefore, a risk assessment of the various theoretical melamine contamination levels in infant formula and selected representative foods (other than infant formula and sole-source nutrition products) is urgently needed for Korean babies and children up to 7 years of age. Although the undetectable level regulation for infant formula may be low enough to guarantee the safety of babies under the age of 1 year (including premature babies), the melamine standard of 2.5 ppm for foods other than baby formula could be insufficient to protect the 95th percentile population aged 1~2 years because of this demographic's high consumption of milk, yogurt, and soy milk (hazard index = 1.79). Because TDIs are chronic values intended to protect an individual over his/her lifetime, occasional modest ingestion in excess of the TDI is not likely to be a health concern. However, children aged 1~2 years may have renal systems that are comparatively more sensitive to the crystallization of melamine and its analogues. Therefore, governmental jurisdictions may need to practice more prudent management of food items that could raise the melamine exposure for this population.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.116-124
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• 2010

While groundwater is the major source for drinking and irrigation purposes, arsenic (As) contamination of groundwater is a serious issue in Bangladesh. With a view to reduce As contamination in drinking water the guideline value recommended for Bangladesh is 0.05 mg/L. We assessed groundwater As in an As-affected Sadar Upazilla (small administrative unit) in the District (administrative unit) of Chapai Nabwabganj during 2006, where 50% hand tube well water were above the recommended limit (0.05 mg/L) during dry season. Almost 20% tube well waters were above the recommended limit during rainy season, perhaps due to the dilution of water table. The groundwater in Bangladesh contaminates surface soils and plants thereby As entering the food chain. In 2005, we examined the As levels in different rice varieties grown in different Districts of Bangladesh and the As concentrations in rice grain ranged from 0.07~1.12 mg/kg while the concentrations in 3 rice varieties were above the recommended limit (1 mg/kg rice grain) and the maximum concentration was 1.12 mg/kg rice grain in the rice variety BR 11. With few exceptions, the As content of rice grain in Bangladesh is not considered to be concentration of greater health concern as yet. We also observed enhanced root uptake, efficient root-to shoot translocation, and a much elevated tolerance through internal detoxification all contribute to As hyperaccumulation in a plant, ladder brake fern (Pteris vittata L.). But the phytoremediation technique might not be an appropriate tool to reduce the As calamity in the vast areas of Bangladesh. To mitigate the As problem of Bangladesh, better coordination among governmental agencies and many other organizations will be required to combat the disaster.

• Food Science of Animal Resources
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• v.23 no.4
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• pp.327-332
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• 2003

This study was conducted to investigate the characteristics of strains which were isolated from market milk treated with ESL(extended shelf life) and conventional system, and to compare the microbiological quality of ESL milk with conventional milk. In order to characterize the isolated strains, purification, Gram staining, spore staining, catalase, oxidase, motility test, and identification by means of automatic identificator were performed. The results obtained are as follows: total 364 selected strains were analyzed in this study. Depending upon the isolated source, the number of strains from conventional milk was found to be Higher than ESL-milk. By means of grouping of total strains, Bacillus ssp. and Staphylococcus ssp. showed to be predominant. But most of strains were distributed with various groups except Lactobacillus ssp. When the isolates were compared with milk process methods, Enterococcus ssp. was detected much on market milk treated with LTLT pasteurization. Also, Pseudomonas ssp. was detected much on conventional milk treated with UHT pasteurization. By comparison with genus groups depending upon storage temperature of market milk, the higher milk storage temperature increased, the most frequency detected Bacillus ssp. increased. Also, Pseudomonas ssp. was detected most frequently at 10$^{\circ}C$ storage condition. Generally this genus derived from post-contamination during milk processing and related to the quality of market milk during chilled system. In conclusion, it was shown that ESL system reduced post-contamination during milk process, following the improvement of product quality and life cycle during the distribution of market milk.

• Journal of dental hygiene science
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• v.15 no.2
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• pp.232-237
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• 2015

The water supplied from dental unit water systems (DUWS) in dentistry may be heavily contaminated with bacteria and thus may be a potential source of infection for both practice staff and patients. The aim of this study was to evaluate the level of heterotrophic bacteria and to confirm the presence of opportunistic pathogens from DUWS in student clinical simulation laboratory of college of dentistry. Water samples were collected from 36 ultrasonic scalers in student clinical simulation laboratory. The levels of heterotrophic bacteria in water samples were quantified by counting colony forming units (CFUs) on R2A agar media. In addition, opportunistic pathogens were detected by using the polymerase chain reaction (PCR) method. The mean CFUs were 16,095 CFU/ml for water samples and all of water samples exceeded current American Dental Association recommendations of 200 CFU/ml. Pseudomonas species and non-tuberculous Mycobacterium species were detected in the one sample and two samples, respectively, among the 36 water samples by the PCR with specific primers for these bacteria. Our study indicated that DUWS in student clinical simulation laboratory can cause potential infection in students and participants. This study suggested the dental unit water line management and wearing personal protective equipment in student clinical simulation laboratory will be needed to reduce bacterial contamination.

• Journal of Korean Society of Environmental Engineers
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• v.28 no.7
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• pp.776-781
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• 2006

Perchlorate ion($ClO_4^-$), which is present in the solid propellant for rocket, herbicide and some fertilizers. Perchlorate inhibits iodide uptake by the human thyroid gland. Impairment of thyroid function in expectant mothers may impact the fetus and result in effects including cerebral palsy, give rise to thyroid gland cancer. The US EPA(Environmental Protection Agency) adopted a reference dose(RfD) for perchlorate 0.0007 mg/kg-day, and this guidance lead to a Drinking Water Equivalent Level(DWEL) of 24.5 ${\mu}g/L$. The studies about perchlorate are actively performed in foreign countries, especially in USA but there is no study which surveyed the perchlorate contamination in Korea. Therefore, this study was done to investigate perchlorate contamination in Nak-dong river and tap water. The perchlorate was detected in Nakdong river and ranged from ND to 278.4 ${\mu}g/L$. The highest concentration was observed in Kumichon. The perchlorate concentration was decreased with the down stream of Nakdong river. The perchlorate concentration in tap water was varied with the cities and the concentration levels were $ND{\sim}34.1$ ppb. The highest perchlorate concentration was observed in DalsuGoo in Daegu and the similar concentration($9{\sim}11$ ${\mu}g/L$) was detected in most of the districts in Busan. The result of this study suggests that there is a perchlorate source near the Nakdong river and the urgent policy is needed to control perchlorate for the cities which are supplied from Nakdong river as for their tap water.