• The Journal of Engineering Geology
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• v.28 no.3
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• pp.411-429
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• 2018

Daeyoung mine (also called "Daema mine") produced gold and silver from mainly gold- and silver-bearing quartz veins. The mine tailings are a waste hazard, but most of the tailings were swept away or dispersed throughout the area around the mine long before the tailing dump areas were transformed into agricultural land. Soil liner and protection facilities, such as retaining walls, were constructed in the mine area to prevent the loss of tailings. The content of the tailings is 3,424.41~3,803.61 mg/kg, which exceeds the safety standard by a factor of 45. In addition, contamination was detected near agricultural areas and in the sediments in downstream drainage channels. A high level of As contamination was concentrated near the waste tailings yard; comparaable levels were detected in agricultural areas close to streams that ran through the waste dump yard, whereas the levels were much lower in areas far from the streams. The contamination in stream sediments showed a gradual decrease with distance from the mine waste yard. Based on these contamination patterns, we concluded that there are two main paths that affect the spread of contaminants: (1) loss of mine waste, and (2) the introduction of mine waste into agricultural areas by floods after transportation by streams. The agricultural areas contaminated by mass inflow of mine waste can act as contamination sources themselves, affecting other agricultural areas through the diffusion of contaminants. At present, although the measured effect in minimal, sediments in streams are contaminated by exposed mine waste and surface liners. It is possible for contaminants to diffuse or spread into nearby areas if heavy elements trapped in soil grains in contaminated agricultural areas leach out as soil solution or contaminant particles during diffusion into the water supply.

• Journal of the Korean Society for Marine Environment & Energy
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• v.14 no.3
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• pp.147-153
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• 2011

This study is to measure the differences of the trace-metals resulted from the different ecologies, such as nickel(Ni), copper(Cu), zinc(Zn), cadmium(Cd), plumbum(Pb), arsenic(As) and chrome(Cr) remaining in the parts of Korean Yeongdeok Crab (KYC) and Russian Snow Crab (RSC) based on ICP-MS. The recovery rate of each metal certified the reference materials (CRM) was in the average of 81~99%, which corresponded with the level required in Codex. The level of metals in the parts of KYC was in the order of Ni > As > Zn > Cu > Cr > Cd in the both male and female shell; the order of Zn > As > Cu > Cr > Ni > Cd in the leg flesh; the order of Zn > As > Cu > Cr > Cd > Ni in the body flesh; the order of Cu > Zn > As > Cd > Cr > Ni in the gill; the order of Cu > As > Zn > Cd > Ni > Cr in the male hepatopancreas; the order of Cu > Zn > As > Cd > Cr > Ni in the female hepatopancreas, thereby showing some differences. It was revealed that the levels of most metals (nickel, copper, zinc, arsenic and chrome) were similar between KYC and RSC except cadmium which was somewhat lower than that of KYC. However, the cadmium in RSC was discovered in high level in most of the parts, two times higher in the hepatopancreas, and four times in the gill. It was also revealed that the trace metal contents were changing according to the size of KYC; the metals with the highest level of Ni in shell, Zn in leg and body flesh, Cu in gill tended to decrease as growing, whereas the cadmium contents tended to increase overall and accumulated the most in hepatopancreas. The results showed there was a possibility that the phenomenon of bioaccumulation within hepatopancreas would increase as growing.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.511-519
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• 2008

Statement of problem: An incompatibility between the initiator systems of self-curing composite resins and light-curing adhesives was supposed recently. Purpose: The purpose of the study was to evaluate the influence of activators for self/dual bonding on dentin shear bonding strengths. Material and methods: Fifty human molars were divided into 5 groups. A flat dentin surface was created for each tooth. A self-curing composite resin (Luxacore) was bonded with the following adhesives (n = 10); One-Step, Prime&Bond NT, AdheSE, Prime&Bond NT and AdheSE were also used in combination with activators. Shear bond strengths were measured after 24 hours of water storage. The specimens were loaded in shear in the Instron until failure at a 1 mm/min crosshead speed. Data were compared using one-way ANOVA and Tukey HSD test (${\alpha}$= 0.05). Results: The dentin adhesive systems in order of decreasing median bond strength were One-Step > Prime&Bond NT with activator, AdheSE with activator > Prime&Bond NT, AdheSE. Among adhesives, One-Step had the highest bond strength. Prime&Bond NT with activator had higher bond strengths than Prime&Bond NT that was used alone, and so was AdheSE. Conclusion: Shear bond strengths were increased in Prime&Bond NT and AdheSE when these were used with activators comparing used without activators. But using activators was not effective clinically comparing One-Step.

• Korean Journal of Animal Reproduction
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• v.22 no.1
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• pp.1-9
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• 1998

This study was carried out to confirm whether the developmental capacity of bovine mature oocytes frozen ultra-rapidly using electron microscopic(EM) grids and EFS30 can be obtained, and whether the cryoprotectants and the freezing method used in this study effect detrimentally to the bovine oocytes by indirect immunocytochemistry. As freezing solution, we used EFS30 which consisted of 30% ethylene glycol, 0.5 M sucrose, 18% ficoll and 10% FBS added in D-PBS. The results obtained in this experiment were summarized as follows: When the effects of cryoprotectant and freezing procedure on the microtuble, micrfilament and chromatin morphology of oocytes were evaluated using indirect immunocytochemistry, the results of freezing as well as exposure group were not different with that of the control oocytes. When the fertilization abnormality after ultrarapid freezing of bovine mature oocytes was examined by Hoechst staining, the rates of total penetration(96.7, 9.0%), normal two pronuclei formation(74.6, 68.9%) and mean number of sperm / oocyte(1.50, 1.44) were not different between control and freezing group. In addition, when the developmental capacity of frozen-thawed of oocytes(85.5%) was survived, 74.5% of them were cleaved and 31.4% of cleaved embryos were developed to blastocyst. These data were similar to those of the control(76.0%, 34.6%) and exposure(74.5%, 33.0%) except survival rates. Also, when the total cell number of blastocysts produced from the each treatment at day after IVF was examined by hoechst staining, there were not different among groups. There results demonstrate that developmental capacity of frozen-thawed bovine mature oocytes can be successfully obtained by ultra-rapid freezing method using EM grid and EFS30 solution.

• Analytical Science and Technology
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• v.23 no.5
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• pp.485-491
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• 2010

A certified reference material (CRM) of KRISS 109-03-SSD was developed for the analysis of hazardous elements in soil. The target elements were As, Cd, Cr, Cu, Hg, Ni, Pb, Zn being regulated by the Soil Environment Conservation Act. Starting material was collected from tailing dump of an unworked tungsten mine at Sangdong (Gangwon-do, Korea). The starting material under-went through a series of fabricating process steps of screening, drying, grinding, sieving, blending, bottling, sterilization and was certified according to the ISO Guide 35. Isotope dilution-inductively coupled mass spectrometry (ID-ICP/MS) and instrumental neutron activation analysis (INAA) were used for the measurement. Homogeneity was tested according to ISO 13528 annex B. The certified values were determined using the results from two different methods or from two independent measurements using a method. Finally, certified values of seven elements of arsenic, cadmium, chromium, copper, lead, nickel and zinc were determined. Mercury did not satisfied the criteria of homogeneity and the result would be provided for information only, together with iron and tungsten. It was also studied, the extractable fraction of elements by aqua regia according to the ISO 11466 protocol being frequently studied for the purpose of environmental monitoring. It was performed as a inter-laboratory study by 6 laboratories of a public institute and universities. Standard deviation among the laboratories was much bigger than the uncertainty of the certified value. The result of inter-laboratory study on the extractable fraction will be provided for information, only.

• Korean journal of food and cookery science
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• v.24 no.1
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• pp.68-75
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• 2008

The aim of this study was to evaluate the quality characteristics and antioxidant activity of yogurt containing spirulina. Yogurt base was prepared from skim milk added with $0.25{\sim}1%(w/v)$ spirulina powder and fermented with lactic acid bacteria (S. thermophilus : L. bulgaricus = 1 : 1) at $40^{\circ}C$ for 12 hr. Kiwi puree and oligosaccharides were then added. The addition of 1% spirulina powder stimulated the growth of lactic acid bacteria, which showed the highest viable cell count ($3.4{\times}10^9$ CFU/mL), and increased the titratable acidity (1.10%). The viscosity range of the yogurt was 6,000 to 9,000 cP, and the sugar content of the yogurt was around 18 $^{\circ}Brix$. The antioxidant activities were determined using the DPPH method, and the hydroxyl radical scavenging activity of the yogurt containing spirulina was higher than that of the control. The sensory evaluation scores for appearance, odor, taste, overall acceptability and buying intention were higher in the yogurt containing 0.25% spirulina than in the other groups. The amount of macronutrients in the yogurt containing spirulina was higher than that in the control. In addition, the amounts of micronutrients in the yogurt containing spirulina was significantly increased. According to these results, the optimum concentration of spirulina powder is around 0.25%.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.182-187
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• 1985

This study was attempted to evaluate the chemical components of Aldaegu, Gadus macrocephalus, which consumed as a salted and dried product popularly in Korea. The contents of such compounds as amino acids, nucleotides and their related compounds, fatty acids and minerals were analysed. The content of total free amino acids was 814.9 mg% on dry basis and the major amino acids were tyrosine, alanine, histidine, leucine, phenylalanine, lysine and valine in a decreasing order. These amino acids were resulted as 45% of total free amino acids in Aldaegu. In the nucleotides and their related compounds, inosine and hypoxanthine were the only compounds detected. The overall content of nucleotide and their related nitrogenous compounds, free amino acid-N., ammonia-N., creatine and creatinine-N., and betaine-N., was 78.6% of extractable nitrogen. Ammonia-N was the most abundant of other nitrogenous compounds, resulting 36.6% of extractable nitrogen from the sample. In the fatty acid composition of total lipid and phospholipid, polyenoic fatty acid was abundant holding about 48% respectively. However, higher amounts of saturated fatty acids(39.8%) were found in glycolipid, and the predominant fatty acids in quantity were palmitic $acid(C_{16:0})$, stearic acid $(C_{18:0})$, oleic $acid(C_{18:1})$, docosahexaenoic $acid(C_{22:6})$, eicosapentaenoic $acid(C_{20:5})$ and eicosatetraenoic $acid(C_{20:4})$. Aldaegu contained 27,430 ppm of sodium and the trace amount of lead and cadmium was detected, which gave a good safety in the food sanitation aspects. It was presumed that free amino acids, ammonia, hypoxanthine, betaine, creatine and creatinine, and minerals play an important role for the characteristics of taste and flavor of Aldaegu.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.18 no.3
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• pp.195-205
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• 1985

As a part of investigation to use the Anatrctic krill, Euphausia superba, more effectively as a food source, processing conditions, utilizations and storage stability of krill paste (intermediate product of krill) were examined and also chemical compositions of krill paste were analyzed. Frozen raw krill was chopped, agitated with $25\%$ of water to the minced krill and then centrifuged to separate the liquid fraction from the residue. This liquid fraction was heated at $98^{\circ}C$ for 20 min. to coagulate the proteins of krill, and it was filtered to separate the protein fraction. Krill paste was prepared with grinding the protein fraction, adding $0.2\%$ of polyphosphate and $0.3\%$ of sodium erythorbate to the krill paste for enhancing of functional properties and quality stability. The krill paste was packed in a carton box, and then stored at $-30^{\circ}C$. Chemical compositions of krill paste were as follows : moisture $78\%$, crude protein $12.9\%$, crude lipid $5.9\%$, and the contents of hazardous elements of krill paste as Hg 0.001 ppm, Cd 1.15 ppm, Zn 9.1 ppm, Pb 0.63 ppm and Cu 11.38ppm were safe for food. The amino acid compositions of krill paste showed relatively high amount of taurine, glutamic acid, aspartic acid, leucine, lysine and arginine, which occupied $55\%$ of total amino acid and also taurine, lysine, glycine, arginine and proline were occupied $65\%$ of total free amino acid. Fatty acid compositions of krill paste consist of $32.4\%$ of saturated fatty acid, $29.6\%$ of monoenoic acid and $38.0\%$ of polyenoic acid, and major fatty acids of product were eicosapentaenoic acid ($17.8\%$), oleic acid ($16.9\%$), palmitic acid ($15.3\%$), myristic acid ($8.7\%$) and docosahexaenoic acid ($8.4\%$). In case of procssing of fish sausage as one of experiment for krill paste use, Alaska pollack fish meat paste could be substituted with the krill paste up to $30\%$ without any significant defect in taste and texture of fish sausage, and the color of fish sausage could be maintained by the color of krill paste. Judging from the results of chemical and microbial experiments during frozen storage, the quality of krill paste could be preserved in good condition for 100 days at $-39^{\circ}C$.