• Journal of Radiation Protection and Research
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• v.37 no.3
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• pp.108-115
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• 2012

The Urban Areas Working Group within the EMRAS-2 ($\underline{E}$nvironmental $\underline{M}$odelling for $\underline{RA}$diation $\underline{S}$afety, Phase 2), which has been supported by the IAEA (International Atomic Energy Agency), has designed some types of accidental scenarios to test and improve the capabilities of models used for evaluation of radioactive contamination in urban areas. For the comparison of the results predicted from the different models, the absorbed doses in air were analyzed as a function of time following the accident with consideration of countermeasures to be taken. Two kinds of considerations were performed to find the dependency of the predicted results. One is the 'accidental season', i.e. summer and winter, in which an event of radioactive contamination takes place in a specified urban area. Likewise, the 'rainfall intensity' on the day of an event was also considered with the option of 1) no rain, 2) light rain, and 3) heavy rain. The results predicted using a domestic model of METRO-K have been submitted to the Urban Areas Working Group for the intercomparison with those of other models. In this study, as a part of these results using METRO-K, the countermeasures effectiveness in terms of dose reduction was analyzed and presented for the ground floor of a 24-story business building in a specified urban area. As a result, it was found that the countermeasures effectiveness is distinctly dependent on the rainfall intensity on the day of an event, and season when an event takes place. It is related to the different deposition amount of the radionuclides to the surfaces and different behavior on the surfaces following a deposition, and different effectiveness from countermeasures. In conclusion, a selection of appropriate countermeasures with consideration of various environmental conditions may be important to minimize and optimize the socio-economic costs as well as radiation-induced health detriments.

• Applied Chemistry for Engineering
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• v.20 no.3
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• pp.241-250
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• 2009

During the past few years, titanium salts were investigated as alternative coagulants for the removal of organic matter of different molecular sizes in contaminated water. The flocculation efficiency of Ti-salt was comparable to those of $FeCl_3$ and $Al_2(SO_4)_3$ salts, commonly used coagulants. Incinerated sludge-$TiO_2$ showed higher surface area and photocatalytic activity than commercially available $TiO_2$. Metal-doped forms were produced by adding coagulant aids such as iron (Fe-), aluminium (Al-) and (Ca-) calcium salts during Ti-salt flocculation to increase pH. Ca- and Al- doped $TiO_2$ showed very high photocatalytic activity compared to Fe-doped $TiO_2$. When tested in a pilot scale plant for treatment of dye wastewater to check practical feasibility of the novel process, the removal ratio of the chemical oxygen demand was comparable to those of commonly used coagulants but the settling of sludge was faster. The $TiO_2$ generated after sludge incineration showed a high photocatalytic activity for degradation of volatile organic compounds and increased the rate of hydrogen production by water photosplitting. $TiCl_4$ coagulant and $TiO_2$ produced from different water sources with different concentrations had low acute toxicity compared to heavy metals and commercial $TiO_2$ when examined based on D. Magna mortality. This paper presents the production, characterisation and the photoactivity of $TiO_2$ produced from Ti-salt flocculated sludge. Different case studies are discussed to highlighted recent advances in this field.

• Journal of Soil and Groundwater Environment
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• v.14 no.2
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• pp.45-53
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• 2009

A quick and simple detection method of explosive compounds in environmental matrix (soil and water) can provide a screening step which reduces the number of unnecessary samples and the cost of expensive laboratory analysis at a site investigation. A commercially available EXPRAY$^{(R)}$Explosives Field Detection Kit (EXPRAY) was used to determine the minimum detection concentration and to test the possibility of semi-quantitative analysis of 14 explosive compounds using standard solutions. The results showed that EXPRAY could detect 5 explosive compounds, TNT, RDX, HMX, Tetryl, and TNB, out of 14 US EPA designated explosives. The minimum detection limit of the nitramine explosives was 14 ng/$^2$ for HMX and RDX. EXPRAY was more sensitive to nitroaromatics than the nitramines and the minimum detection limits per unit area (mm$^2$) for Tetryl, TNB, and TNT, were 3 ng, 3 ng, and 0.3 ng, respectively. The semi-quantification of 5 explosive compounds in an order ofmagnitude could be achieved by the intensity of developed color only when EXPRAY was applied on the standard solutions under controlled laboratory conditions. With contaminated soil samples, however, only the presence and type of explosive compounds was identified. Therefore, EXPRAY is an economic and sensitive method that can be used in a screening step for the identification of explosives in the field samples.

• Journal of Life Science
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• v.22 no.2
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• pp.239-244
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• 2012

The purpose of this paper is to analyze the characteristics and chemical components of biosurfactant produced by Pseudomonas sp. G314. Pseudomonas sp. G314 was isolated from soil samples which were contaminated with oil in Daejon area. As such, it produced quality biosurfactant [23]. One type of biosurfactant was kept in a refrigerator, whereas another type of biosurfactant was kept in room temperature. The surface tension activities were then compared. As a result, the biosurfactant from Pseudomonas sp. G314 that was kept at room temperature was stable for 10 days, showing 26.2 dyne/cm of surface tension activity. This result was found to be similar to that of the refrigerator storage. The surface tension of batch culture was 25 dyne/cm, but the culture in the 5 l fermentor was 27 dyne/cm. Therefore, it can be suggested that the large-scale culture is feasible via the fermentor. Biosurfactant from Pseudomonas sp. G314 was estimated to be a kind of glycolipid because it dissolved in acetone and methanol much better than in benzene and toluene [23]. A spot was detected through the elution of silica gel column and the spread of TLC, and the Rf value was 0.58. This spot has a positive reaction with Bail's reagent and rhodamine 6G. Hence, we can conclude that biosurfactant from Pseudomons sp. G314 was a glycolipid containing carbohydrate and lipid.

• Journal of Food Hygiene and Safety
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• v.15 no.4
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• pp.315-323
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• 2000

Serious consequences can arise from lack of hygiene in mass catering. Microbiological testing is of value in determining hazards for developing a HACCP plan, and in demonstrating to food handlers the reality of the microbial risk. This studies was performed to describe the overall hygiene of cooking utensils and equipments, employees, and environment in mass catering establishments. Generally, hygienic conditions of cutting board and sanitized dish cloth were better than those of other cooking utensils such as knife, sieve, and peeler. It was found that the cross-contamination of knife might be caused by the use of contaminated sanitizing solution. It was observed that there was considerable variation (10$^1$~10$^{5}$ CFU) of the number of general bacteria for employee's hands. The number of general bacteria were influenced from establishment, employee, and the period of analysis. The number of Coliform group for employee's hands was in the range of 10$^2$~10$^4$CFU only at the first analysis. Total aerial bacteria in working area of mass catering establishments was below 7 CFU/Plate and aerial Staphylococcus sp. was not detected at all except one spot.

• Journal of Korean Academy of Nursing
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• v.25 no.1
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• pp.99-109
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• 1995

Post-operative wound infections have been the serious problems in nursing care in the operating room and appear to be strongly related to the infection occurring during the operation. The purpose of this study is to identify the level of contamination in saline used in the operation and also examine the correlation between the contaminated saline and the length of the operation, and unclean atmospheric factor. Subjects for this study include 13 cases of operation performed at the operative theatre of a hospital in Seoul area. Test samples and related data were collected from this medical facility between Oct. 6 through Dec. 10, 1994 by the author and anurse who worked in the operating room. For the study, multiple batches of saline sample were collected at the various time intervals duringthe operation and filtered through the membrane filters. Viable microorganisms retained on the filters were cultured on the appropriate culture media and the levels of existing cells in saline were enumerated according to Koch's method. In the analyses of the data, Pearson's correlation coefficient was obtained for the examination of relationship between the length of operation and numbers of microorganisms existing in saline and for the comparison of the differences in numbers if microrganisms in saline sample collected at the various operative stages, e. g. pre-incision, excision and skin suturing stages, ANOVA and Scheff Tests were performed. The results of this study are summarized as follows. 1) The lenth of the operation and numbers of microorganisms in the saline used in the operation appeared to be significantly correlated (r=0.5467, P<0,001). 2) In case of saline exposed to air, but not used in the operation, the length of exposure to the air and the numbers of microorganisms present in saline also showed an apparent correlation(r=0.5087, P<0. 001). 3) The frequencies of occurrence of microorganisms in saline used in the operation and in saline exposed only to the air in the given time showed significant differences(t=3.73, p=.0000). 4) In case of saline used in the operation, there is significant differences in its numbers of contained microorganisms between the operative stages ; pre-incision, excision, and skin suture (F=17.7500, p=.0000). 5) In case of saline exposed only to the air in the given time, there is significant differences in its numbers of contained microorganisms between the operative stages . pre-incision, excision, and skin suture(F=6.3807, p=.00031).

• Korean Journal of Environmental Agriculture
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• v.19 no.3
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• pp.213-217
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• 2000

In order to select more proper plants for phytoextraction at the heavy metal polluted areas, 11 species of non-edible plants were cultivated at the cadmium(Cd) and Lead(Pb) treated soils and analyzed the content of the absorbed Cd and Pb in each part of plants. Plants include three fibers(Linum usitatissimum, Cannabis sativa, Gossypium spp.), three flowers(Calendula officinalis, Rhododendron lateritium, Portulaca grandiflora), and five trees(Pinus thunbergii, Magnolia kobus, $Populus\;nigra\;{\times}\;P.$ maximowiczii, Euonymus japonica, Fraxinus rhynchophylla). Yield of tree species were higher than that of fiber and flower species. Cd and Pb were highly accumulated in root rather than leaves and stems. The Cd content of plants was in the order Portulaca grandiflora > Calendula officinalis > Gossypium spp. > Linum usitatissimum, Pb was Cannabis sativa > Linum usitatissimum > Fraxinus rhynchophylla. Total absorbed Cd by each plant was in the order $Populus\;nigra\;{\times}\;P.$ maximowiczii > Euonymus japonica > Rhododendron lateritium, but Pb was $Populus\;nigra\;{\times}\;P.$ maximowiczii > Rhododendron lateritium > Euonymus japonica. Total absorbed Cd and Pb contents in plants were negatively correlated with the residual Cd and Pb in the treated soils. It was estimated that $Populus\;nigra\;{\times}\;P.$ maximowiczii, Euonymus japonica, Fraxinus rhynchophylla, and Rhododendron lateritium were the most effective species for phytoextraction in the polluted area considering yield and heavy metal uptake.

• Economic and Environmental Geology
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• v.28 no.1
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• pp.25-31
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• 1995

In Dongnam area, Cretaceous igneous rocks, such as diorite, porphyritic granite, and quartz porphyry intruded Paleozoic sedimentary rocks, such as Myobong slate and Pungchon limestone. The Dongnam Fe-Mo skarn deposits were imposed on the diorite(endoskarn) and the Myobong slate(exoskarn). The ore deposits consist mainly of magnetite and molybdenite with small amounts of sulfides, such as galena, sphalerite, pyrite, chalcopyrite, and pyrrhotite. The igneous rocks show nearly constant $^{206}Pb/^{204}Pb(18.80{\sim}19.06)$ and $^{207}Pb/^{204}Pb(15.71{\sim}15.72)$ ratios. Their $^{207}Pb/^{204}Pb$ ratios higher than the typical ratios of orogene suggest that the igeneous rocks were formed from lower crust(or mantle) - derived magma excessively contaminated by upper crustal materials such as high radiogenic Precambrian basement rocks. The lead isotopic compositions of the igneous rocks, the Pungchon limestone, and the ore minerals show a well defined linear in $^{206}Pb/^{204}Pb$ - $^{207}Pb/^{204}Pb$ plot. The lead isotopic compositions of the igneous rocks are similar to those of magnetite and galena, which were formed at early skarn stage and significantly lower than those of altered quartz porphyry, molybdenites, and pyrite, which were formed at late epithermal alteration stage. Considering the systematic variation of the lead isotopic compositions in the ore minerals according to hydrothermal stages, the variation may be due to a relative variation in surrounding rock(Pungchon limestone) involvement in hydrothermal ore solution leaching the surrounding rock. Therefore, the variation of the lead isotopic compositions in ore minerals can be modeled in terms of the mixing of the leads derived from the igneous rocks as low radiogenic source and the surrounding rock(Pungchon limestone) as high radiogenic source.

• Journal of the Society of Disaster Information
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• v.16 no.3
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• pp.542-549
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• 2020

Purpose: As nitrate nitrogen produced during fermentation of liquid fertilizer is a pollution indicator of water, in this study, four research areas where liquid fertilizer was sprayed were selected, and a model was designed to estimate the concentration of nitrate nitrogen pollution. Method: Prior to shooting on site, a spectrum library was constructed by dividing the ratio of liquid fertilizer into 5 groups: 0%, 25%, 50%, 75%, and 100%. PLSR (Partial least squares regression) method was applied to hyperspectral images acquired in the study area based on the aspect of spectrum. Result: The behavior of nitrate nitrogen was confirmed by 1st and 2nd differentiation of the spectrum of the constructed liquid fertilizer. PLSR concentration estimation modeling was implemented using images from field experiments and compared with actual concentration of nitrate nitrogen. Conclusion: When comparing the PLSR concentration estimation model with the actual concentration of nitrate nitrogen, it was measured that the detection is possible in high concentration areas where the concentration of nitrate nitrogen is 70mg/kg or more.

• Analytical Science and Technology
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• v.25 no.6
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• pp.350-363
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• 2012

To determine ionic species in snowpit samples using ion chromatography system, we described the performance of ion chromatography(IC) system, cleaning method of bottle, and interference by filtering procedure. The limit of detection, reproducibilities, and accuracies determined with BCR$^{(R)}$-408 were 0.01-0.26 ${\mu}g$/L, 0.4-17.4%, 4.5-12.0% for cations and 0.02-0.26 ${\mu}g/L$, 0.1-27.6%, 1.3-5.6% for anions, respectively. Lab blank test for sample bottle indicated that $CH_3CO_2{^-}$, $HCO_2{^-}$, and $NH_4{^+}$ can be easily contaminated in the lab environment. The positive interferences of $NO_3{^-}$ were partly attributed to the cleaning method of bottle. The filtering of melted snow sample should be carefully applied because it can positively affect the concentration levels of some ionic species. Finally, this method was applied to measure ionic species in snowpit samples from the upward area near NEEM camp and the uncertainties of measurement data of $F^-$ were also estimated.