• Polymer(Korea)
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• v.30 no.6
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• pp.525-531
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• 2006

In this study, Sulfonated PONF-g-styrene ion exchange fibers were synthesized by radiation induced graft copolymerization. And also, hybride ion exchange fibers, which was combined sulfonated PONF-g-styrene fibers and cationic ion exchange resin, were fabricated by hot melt adhesion method and then their adsorption properties were investigated. ion exchange capacity and water content of hybrid ion exchange fibers increased as compared with those of bead and ion exchange fiber. Their maximum values were 4.76 meq/g and 23.5%, respectively. Adsorption breakthrough time for mercury of hybrid ion exchange fiber was slower than those of bead resin and fibrous ion exchanger. It's value was 130 minutes. Their breakthrough time become short as increasing of pH, and concentration. The initial breakthrough time was observed before and after 10 minutes as increasing of concentration. The adsorption of hybrid ion exchange fibers for $Hg^{2+}\;Pb^{2+},\;Cd^{2+}$ among heavy metals in the mixed solution was observed before 20 min. And also, The adsorption for $Hg^{2+}$ among the heavy metals by hybride ion exchange fibers was observed.

• Journal of the Korean Wood Science and Technology
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• v.42 no.3
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• pp.318-326
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• 2014

This study was conducted to investigate the potential of non-used forest biomass residues as raw materials for making wood pellets with additives such as wood tar and starch and to evaluate fuel characteristics of the pellets. Wood tar, a by-product provided from the carbonization process of wood, could be a suitable additive for wood pellet production due to its higher calorific value and lower hazardous heavy metals, such as cadmium and mercury, compared to woody biomass. When the wood tar (10 wt%) was added, the calorific value was increased from 4,630 kcal/kg (wood pellet without additive) to 4,800 kcal/kg (wood pellet with additive). With the increase of additive amount into wood pellet, the length and individual density of wood pellet increased. In addition, bulk density of the pellets was increased, whereas the fine content was decreased. Consequently the overall productivity of wood pellets was improved by adding 2 w% additives into wood pellets; the percentage of productivity increase was 5.9% and 4.9% for adding starch and wood tar, respectively.

• YAKHAK HOEJI
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• v.57 no.1
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• pp.8-17
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• 2013

The objective of this study is investigation of contamination levels and transfer rate of heavy metals and assessment of health risk effects in animal medicines. A total of sixteen items with 148 samples were obtained for this investigation from major herbal medicine producing areas and herbal markets from 2011 to 2012. Inductively coupled plasma mass spectrometer method was conducted for the quantitative analysis of Pb, Cd and As. In addition, the mercury analyzer system was conducted for that of Hg without sample digestion. The average contents of heavy metals in animal medicines were as follows : 1.55 mg/kg for Pb, 0.28 mg/kg for Cd, 0.70 mg/kg for As and 0.047 mg/kg for Hg respectively. The average contents of heavy metals in decoctions were as follows : 0.03 mg/kg for Pb, 0.01 mg/kg for Cd, 0.17 mg/kg for As and 0.003 mg/kg for Hg respectively. The average transfer rates of heavy metals from animal medicines to decoctions were 1.9% for Pb, 3.6% for Cd, 24.2% for As and 6.0% for Hg respectively. Cancer risks of animal medicines and decoctions through slope factor by ministry of environment republic korea and environmental protection agency was $1.36{\times}10^{-6}$ and $2.50{\times}10^{-8}$ for Pb and $7.46{\times}10^{-5}$ and $1.98{\times}10^{-5}$ for As (assuming that the total arsenic content was equal to the inorganic arsenic) respectively. The hazard index of heavy metals in animal medicines and decoctions was below recommended hazard index as 0.52 and 0.05 respectively. Taken together, cancer risks about Pb and hazard indexes of animal medicines and decoctions indicate that the majority of samples except for some samples with relative high contents of heavy metals were safe. But cancer risks about As of animal medicines indicate that the majority of samples were not relatively safe.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.19-29
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• 1994

A large volume of paper mill sludge(PMS) is produced every day from paper industries after treatments of waste water and it costs too much to dispose of the sludge. Since PMS consists mostly of biodegradable organic matter, cellulose, it is desirable to recycle it by proper treatments such as composting. In this study, experiments were conducted using a small scale reactor(12l) to establish optimum conditions for efficient composting of PMS of which initial pH, C/N ratio, and moisture content were 7.1, 28~30, and 60~65%, respectively. No heavy metals such as mercury, cadmimum, and lead were not detected in the PMS. Various levels of forced aeration, 1 minute aeration per every 30, 60, 120, 240, and 480 minutes were applied and 1 minute aeration per 60 and 120 minutes found to be proper for composting of 8l PMS in this system. Relationship between $CO_2$ production and temperatures was positively correlated with r> 0.82 suggesting that the normal decomposition of PMS by microorganisms occurred. However, under the condition of aeration interval over than 240 minutes, a negative relationship between two parameters was found indicating the occurrence of abnormal(maybe anaerobic) degradation. The amount of added nitrogen also affected composting of PMS resulting in the increase of $CO_2$ production and temperature. Semi-field tests using 100kg PMS in a static pile sysem showed that PMS could be composted efficiently under optimal environmental conditions. The parameters determining efficiency of composting such as C/N ratio, aeration, moisture content, and pH need to be monitored.

• Korean Journal of Food Science and Technology
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• v.43 no.4
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• pp.413-418
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• 2011

This survey was conducted to monitor the safety of red ginseng products in Gwangju, in 2010. Among 100 samples, 37 were beverages, 5 were functional health foods on the market, and 58 were beverages from a tailor-made shop. All samples were negative for coliform bacteria. Aerobic plate counts were detected from 13 samples in the 58 tailor-made products but not detected in the other types of products. Benzoic acid was detected in 5 samples (range, 19.2-543.0 mg/kg). Among heavy metals, lead was detected, ranging from 28.8-62.3 ${\mu}g/kg$, cadmium, from 1.15-4.18 ${\mu}g/kg$, and mercury from 0.10-0.18 ${\mu}g/kg$. Benzopyrene was not detected in any samples. Ginsenoside Rg1 and Rb1 were detected in 0.1-23.4 mg/90 mL of beverages and 12.1-66.8 mg/90 mL of functional health foods. These results indicate that red ginseng products are safe in terms of microbial contaminants and hazardous chemical compounds such as heavy metals and benzopyrene.

• Journal of Food Hygiene and Safety
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• v.27 no.4
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• pp.375-387
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• 2012

The objective of this study is investigation of contamination levels and assessment of health risk effects of heavy metals in herbal pills. 31 Items and 93 samples were obtained for this investigation from major herbal medicine producing areas, herbal markets and on-line supermarkets from Jan to Jun in 2010. Inductively coupled plasma mass spectrometer method was conducted for the quantitative analysis of Pb, Cd and As. In addition, the mercury analyzer system was conducted for that of Hg without sample digestion. The average contents of heavy metals in samples were as follows : 0.87 mg/kg for Pb, 0.08 mg/kg for Cd, 2.87 mg/kg for As and 0.16 mg/kg for Hg, respectively. In addition, the average contents of heavy metals in different parts of plants, including cortex, fructus, herba, radix, seed, algae and others were 0.63 mg/kg, 3.94 mg/kg, 1.42 mg/kg, 1.05 mg/kg, 0.16 mg/kg, 22.31 mg/kg and 10.17 mg/kg, respectively. After the estimations of dietary exposure, the acceptable daily intake (ADI), the average daily dose (ADD), the provisional tolerable weekly intake (PTWI) and the relative hazard of heavy metals were evaluated. As the results, the relative hazards compared to PTWI in samples were below the recommended standard of JECFA as Pb 3.1%, Cd 0.9%, Hg 0.5%. Cancer risks through slope factor (SF) by Ministry of Environment Republic Korea and Environmental Protection Agency was $4.24{\times}10^{-7}$ for Pb and $3.38{\times}10^{-4}$ for As (assuming that the total arsenic content was equal to the inorganic arsenic). Based on our results, possible Pb-induced cancer risks in herbal pills according to parts used including cortex, fructus, herba, radix, seed, algae and others were $1.95{\times}10^{-7}$, $1.45{\times}10^{-6}$, $2.14{\times}10^{-7}$, $6.27{\times}10^{-7}$, $1.99{\times}10^{-8}$, $3.61{\times}10^{-7}$ and $9.64{\times}10^{-8}$, respectively. Possible As-induced cancer risks in herbal pills by parts used including cortex, fructus, herba, radix, seed, algae and others were $1.54{\times}10^{-5}$, $7.24{\times}10^{-5}$, $1.23{\times}10^{-4}$, $2.02{\times}10^{-5}$, $3.25{\times}10^{-6}$, $2.18{\times}10^{-3}$ and $5.67{\times}10^{-6}$ respectively. Taken together, these results indicate that the majority of samples except for some samples with relative high contents of heavy metals were safe.

• Analytical Science and Technology
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• v.28 no.6
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• pp.436-445
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• 2015

Amomi Fructus with anti-oxidative activity was chosen and essential oil was obtained by SDE (simultaneous distillation extraction), and 39 constituents were determined by GC-MS (gas chromatography-mass spectrometry). Major components were camphor, borneol acetate, borneol, D-limonene and camphene. Three solvent extracts such as hexanes, diethyl ether and methylene chloride from Amomi Fructus were obtained. These were analyzed by GC-MS and 4 more constituents were identified in addition to 39 components discovered in essential oil. Five major components such as camphor, borneol acetate, borneol, D-limonene and camphene were also detected, however the relative peak percents of those components were different from those of constituents in essential oil. To estimate the kind and the amount of materials evaporated at certain temperature and conditions from essential oil and solvent extracts, dynamic headspace apparatus was used and materials evaporated and trapped at certain conditions were analyzed by GC-MS. Recovery yield of SDE method from Amomi Fructus was measured by using camphor and standard calibration solution of camphor methanol solution and, the yield was 82.0%. Content of Hg was measured by mercury analyzer and contents of Cd, Pb, Cr, Mn, Co, Ni, Cu and Zn in Amomi Fructus, essential oils and solvent extracts were determined by ICP-MS (Inductively coupled plasma-mass spectrometer). Pb, Cd and Hg were measured in the concentration of 0.72 mg/kg, <0.10 mg/kg and 0.0023 mg/kg, respectively and these were below permission level of purity test. Contents of Mn, Cu and Zn in Amomi Fructus were 213 mg/kg, 8.29 mg/kg and 31.0 mg/kg, respectively and which were relatively higher than other metals such as Cr, Co and Ni. Metals such as Mn (0.65 ~ 9.08 mg/kg), Cu (1.16 ~ 4.40 mg/kg) and Zn (1.10 ~ 3.80 mg/kg) in essential oil and solvent extracts were detected. At this point it is not clear that the metals were cross-contaminated in the course of treating Amomi Fructus or metals were contained in Amomi Fructus. The influence evaluation toward biological model study of these metals in essential oil and solvent extracts will be needed.

• Journal of the Korea Concrete Institute
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• v.19 no.5
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• pp.613-621
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• 2007

Due to the increasing significance of durability, much researches on carbonation, one of the major deterioration phenomena are carried out. However, conventional researches based on fully hardened concrete are focused on prediction of carbonation depth and they sometimes cause errors. In contrast with steel members, behaviors in early-aged concrete such as porosity and hydrates (calcium hydroxide) are very important and may be changed under carbonation process. Because transportation of deteriorating factors is mainly dependent on porosity and saturation, it is desirable to consider these changes in behaviors in early-aged concrete under carbonation for reasonable analysis of durability in long term exposure or combined deterioration. As for porosity, unless the decrease in $CO_2$ diffusion due to change in porosity is considered, the results from the prediction is overestimated. The carbonation depth and characteristics of pore water are mainly determined by amount of calcium hydroxide, and bound chloride content in carbonated concrete is also affected. So Analysis based on test for hydration and porosity is recently carried out for evaluation of carbonation characteristics. In this study, changes in porosity and hydrate $(Ca(OH)_2)$ under carbonation process are performed through the tests. Mercury Intrusion Porosimetry (MIP) for changed porosity, Thermogravimetric Analysis (TGA) for amount of $(Ca(OH)_2)$ are carried out respectively and analysis technique for porosity and hydrates under carbonation is developed utilizing modeling for behavior in early-aged concrete such as multi component hydration heat model (MCHHM) and micro pore structure formation model (MPSFM). The results from developed technique is in reasonable agreement with experimental data, respectively and they are evaluated to be used for analysis of chloride behavior in carbonated concrete.

• Journal of the Korean Society of Food Science and Nutrition
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• v.42 no.8
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• pp.1270-1276
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• 2013

Laver, a red algae belonging to the genus Porphyra tenera, is one of the most widely consumed edible seaweeds in Korea, China, and Japan. Lavers are usually consumed in dried, roasted, and seasoned forms to improve their palatability. We evaluated the composition of amino acids, minerals, and trace heavy metals in these three differently cooked forms of laver. The moisture and ash contents of three differently cooked lavers ranged from 1.49~9.69% and 6.07~10.31%, respectively. The crude protein and lipid content ranged from 17.24~36.88% and 0.52~42.42%, respectively. Dried laver was found to be a good source of amino acids such as taurine, alanine, and glutamic acid (871.10 mg, 833.53 mg, and 719.77 mg per 100 g dry weight, respectively). Laver was a good source of macro and micro minerals such as K, Ca, Mg, Na, P, I, and Fe, although laver more extensively cooked (roasted and seasoned) contained less minerals compared to the dried form. Mercury levels in the three differently cooked forms of laver were all less than 100 ng/g dry weight (the limit of detection with our methodology). The levels of arsenic were the most abundant elements in the differently cooked laver. There was a clear variation, depending on the cooking process, in terms of amino acid, mineral, and trace metal contents of laver.

• Journal of Food Hygiene and Safety
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• v.31 no.4
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• pp.258-263
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• 2016

The risks of sanitary indicative bacteria, heavy metals and chlorinated derivatives in 94 cases of sanitary wet towels used in food services (39 from sanitary wet towel treatment business, 55 from food services) were assessed in the present study. Lead was detected in the range of N.D.~0.41 mg/kg (75 cases were not detected), N.D.~0.25 mg/kg of arsenic (93 cases were not detected), N.D.~0.01 mg/kg of cadmium (7 cases were lower than limit of quantitation; 87 cases were not detected), 0.003 mg/kg ~ 0.09 mg/kg of mercury. And chromium (VI) was not detected from all samples. The level of lead was the highest among the tested heavy metals, and the highest concentration of lead was 0.41 mg/kg. However, it was only 2.1% of legal limit (less than 20 mg/kg). The average moisture content of the samples was 61.9% (50.0% ~ 77.0%) and it showed no relevance to the detection of bacterial counts. Escherichia coli was not detected. Bacterial counts were detected 43 cases and among them, 24 cases were exceeded the legal limit. It was verified that the packaging conditions of sanitary wet towel (whether it is packed by a piece or not and sealed or not) are critical factors to cause the germ contamination and cross contamination in the wet towels. The chlorinated derivatives (chlorites and chlorates) were detected in 17 (19.3%) out of 88 cases. The results would be used as preliminary information to establish the programs of "Safety education for manufacturers and public policy of safety".