• Korean Journal of Food Science and Technology
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• v.18 no.4
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• pp.249-254
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• 1986

An experiment was performed to investigate the combined effect of preservatives and the synergistic effect of sodium chloride to them on the inhibition of bacterial growth. Escherichia coli and Salmonella typhimurium were cultured with or without shaking in liquid media (pH 6) of tryptone-glucose-yeast extract or tryptic soy broth which contained 0.1% potassium sorbate and/or 0.03% sodium benzoate, equivalent to half of the maximum permissible levels, respectively. The growth of E. coli was more inhibited with one or both of the two preservatives by shaking culture than by non-shaking culture. For S. typhimurium the single treatment of the preservatives did not show inhibitory effect whereas the combined treatment of them showed bacteriostatic effect in shaking culture and a prolongation of lag phase in non-shaking culture. Addition of 2% sodium chloride to either potassium sorbate or potassium sorbate plus sodium benzoate remarkably increased the growth inhibition of E. coli for non-shaking cultivation but no effect observed for shaking cultivation. S. typhimurium was more sensitive to the addition of sodium chloride than E. coli in both shaking and non-shaking culture to show lower viable cell counts than initial numbers.

• Korean Journal of Environmental Agriculture
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• v.39 no.1
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• pp.75-82
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• 2020

BACKGROUND: This study was carried out to establish pre-harvest residue limits (PHRLs) of indoxacarb and pymetrozine in broccoli under greenhouse conditions, based on dissipation patterns and biological half-lives of pesticides during 10 days after application. METHODS AND RESULTS: The field studies were conducted in two different greenhouse, located in Chungju-si (Field 1) and Gunsan-si (Field 2). Samples were collected at 0, 1, 2, 3, 5, 7 and 10 days after spraying pesticide suspension. The analytical methods for indoxacarb and pymetrozine using HPLC-DAD were validated by recoveries ranging of 94.3-105.4% and 81.8-96.0%, respectively, and MLOQ (Method Limit of Quantification) of 0.05 mg/kg. Biological half-lives of indoxacarb and pymetrozine were 2.9 and 3.2-3.8 days in broccoli, respectively. The lower 95% confidence intervals of dissipation rate constant of indoxacarb were determined as 0.1508 (Field 1) and 0.2017 (Field 2), whereas those of pymetrozine were calculated as 0.1489 (Field 1) and 0.1577 (Field 2). CONCLUSION: The significant differences were not observed between the dissipation rates of indoxacarb and pymetrozine in broccoli. The major factor affecting residue dissipation was the dilution effect by fast growth. The PHRLs for 10 days prior to harvest were recommended as 30.06 (Field 1) and 18.07 (Field 2) mg/kg for indoxacarb, and 4.84 (Field 1) and 4.43 (Field 2) mg/kg for pymetrozine, respectively.

• Research in Plant Disease
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• v.11 no.2
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• pp.179-184
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• 2005

A previous study reported that the stem and root rot of paprika (Capsicum annum L. var, grossum) caused by Nectria haematococca became a threat to safe cultivation of the plant in the country. However, no strategies for control the disease have been suggested. In this study, fungicides registered for pepper were screened to evaluate their control effects on the disease. Among fungicides tested, prochloraz manganase complex com pletely suppressed mycelial growth of the pathogen at 10 ppm a.i. tebuconazole, benomyl, and carbendazim $\cdot$kasugamycin also effectively inhibited mycelial growth of the fungus. However, kresoxim-methyl and triflox ystrobin did not suppress mycelial growth but significantly suppressed conidial germination of the fungus. Azoxystrobin, benomyl, prochloraz, tebuconazol, and carbendazim$\cdot$ kasugamycin were also effective to retard conidial germination. In vivo tests, tebuconazole strongly inhibited the plant growth even at 16,000x (15.6 ppm a.i.), while others did not induce chemical injury at 4,000x or 8,000x when drenched into a rockwool cube. In a greenhouse test, prochloraz manganase complex at 125 ppm a.i. (4,000x) showed highest control value by $89.9\%$. Other fungicides thiophanate-methylthiram, axozystrobin, trifloxystrobin, and benomyl presented $60-80\%$ control value in the hydroponic cultivation system. However, application time and interval remained to be investigated for identify maximum residue limit.

• Journal of Korean Society on Water Environment
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• v.26 no.1
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• pp.1-9
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• 2010

Technology-Based Effluent Limitations (TBELs) is a permit limits for a pollutant that is based on the capability of a treatment technology to reduce the pollutant to a certain concentration. Widely practiced for regulations of industrial wastewater in US, TBELs has been accepted as an effective means that can achieve balanced goals between complete elimination of pollutants discharge and economic feasibility for industries. The review of TBELs application in US and the applicability of TBELs to the domestic industry categories was given in three papers. In the first paper, the development and practices of TBELs in US were reviewed including case studies. The developments of TBELs in US in the four major categories, the metal products & machinery, the petroleum refining, the porcelain enameling and the meat & poultry products were reviewed. The applicability of TBELs to the domestic industrial categories was also assessed. In the second paper, the pollution loads analysis for domestic industrial wastewater was conducted based on risk assessment indicator using Toxic Weighting Factors (TWFs). This is an essential part to determine the priority of TBELs application for the domestic industrial categories. In the last paper, the application of TBELs to the domestic industries was demonstrated through a case-study for the pulp/paper/paperboard category. Direct application of TBELs of US into the Korean regulation system may not be desirable because the specific goals and the environment for the regulations for the two countries may not be identical. For example, unlike US, Korea does not adopt the individual permit system for pollution sources. However, among the unproductive and exhaustive controversies over the uniform regulations regardless of the industrial categories in Korea, the introduction of the principles of TBELs are inevitable and more extensive study for applications of TBELs optimized for Korean regulation system will be necessary.

• Journal of the Mineralogical Society of Korea
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• v.24 no.2
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• pp.119-131
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• 2011

The asbestos contents in some representative building materials were analyzed using JIS (Japanese Industrial Standard) X-ray diffraction (XRD) method. The changes in mineral composition during analysis process and problems in JIS method were also examined. XRD analysis of some representative domestic building materials used for roof, wall, ceiling, and floor indicates that slate have the highest asbestos content having 6.87~6.93% of chrysotile. Other building materials analyzed in this study also have 1.35~3.98% of chrysotile contents. The XRD analysis results of asbestos contents in some domestic building materials are presented in this study. This method is very effective for the asbestos content evaluation of building materials according to newly modified asbestos content regulation (Law of Industrial Safety and Health, 2007-26) that limits asbestos content less than 0.1% by Ministry of Employment and Labor. Small amount of tremolite as well as chrysotile were also observed in some samples. With consideration of crystal shape, contents and geological occurrence, it is considered that tremolite is an associated mineral of chrysotile and is not intentionally added. Complemental analyses with optical microscope and SEM/EDS are also necessary because XRD method cannot distinguish asbestiform from non-asbestiform. The XRD method applied in this study is very effective in the asbestos content analysis of building materials, specially building materials showing high asbestos concentration in residues due to the high loss rate with ashing and acid dissolution procedure.

• Korean Journal of Environmental Agriculture
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• v.22 no.2
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• pp.130-136
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• 2003

An organophosphorus insecticide, chlorpyrifos and an arylnitrile fungicide, chlorothalonil commonly used far apple were subjected to a residual investigation under field conditions to ensure safety of terminal residues at harvest. After pesticides were applied at standard rate in apple tree fer 15 days for chlorpyrifos and 30 days far chlorothalonil, persistence of their residues in apple was investigated by several interval. At harvest, residual concentrations of chlorpyrifos and chlorothalonil in apple were 1.3 and 2.4mg/kg, respectively, and the residue levels were higher than MRL 1.0 mg/kg in Korea. As well fitted by the first-oder kinetics, biological half-lives of the pesticide residues in apple were 9.3 days for chlorpyrifos and 32.2 days for chlorothalonil. During the storage, half-lives of chlorpyrifos and chlorothalonil were 35.0 and 56.3days at room temperature, and 120.7 and 182.8 days at 412, respectively. Distribution of chlorpyrifos residue in flesh, fruit skin and stalk cavity of each apple corresponded to 0.1% 22.8% and 77.1%, respectively. In case of chlorothalonil, residue in flesh, fruit skin and stalk cavity was 4.4%, 10.4% and 85.2%, respectively.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.34 no.1
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• pp.53-62
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• 2016

In recent years, UAV Photogrammetry based on an ultra-light UAS(Unmanned Aerial System) installed with a low-cost compact navigation device and a camera has attracted great attention through fast and accurate acquirement of geo-spatial data. In particular, UAV Photogrammetry do gradually replace the traditional aerial photogrammetry because it is able to produce DEMs(Digital Elevation Models) and Orthophotos rapidly owing to large amounts of high resolution image collection by a low-cost camera and image processing software combined with computer vision technique. With these advantages, UAV-Photogrammetry has therefore been applying to a large scale mapping and cadastral surveying that require accurate position information. This paper presents experimental results of an accuracy performance test with images of 4cm GSD from a fixed wing UAS to demarcate parcel boundaries in agricultural area. Consequently, the accuracy of boundary point extracted from UAS orthoimage has shown less than 8cm compared with that of terrestrial cadastral surveying. This means that UAV images satisfy the tolerance limit of distance error in cadastral surveying for the scale of 1: 500. And also, the area deviation is negligible small, about 0.2%(3.3m²), against true area of 1,969m² by cadastral surveying. UAV-Photogrammetry is therefore as a promising technology to demarcate parcel boundaries.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.1
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• pp.66-72
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• 2020

This study aimed to discuss the optimal seeding and harvesting dates with growing degree days(GDD) via meta-data of whole crop maize(WCM). The raw data (n=3,152) contains cultivation year, cultivars, location, seeding and harvesting dates collected from various reports such as thesis, science journals and research reports (1982-2012). The processing was: recording, screening and modification of errors; Then, the final dataset (n=121) consists of seeding cases (n=29), and harvesting cases (n=92) which were used to detect the optimum. In addition, the optimal periods considering tolerance range and GDD also were estimated. As a result, the optimum seeding and harvesting periods were 14th April ~ 3rd May and 15th August ~ 4th September, respectively; where, their GDDs were 23.7~99.6℃ and 1,328.7~1,602.1℃, respectively. These GDDs could be used as a judge standard for selecting the seeding and harvesting dates.

• Korean Journal of Food Science and Technology
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• v.45 no.4
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• pp.409-415
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• 2013

Post-harvest fungicide residue was measured in citrus fruits. Samples were collected from local markets in Seoul and analyzed using liquid chromatography coupled with mass spectrometry (LC-MS). LC-MS results were validated for the assay of pesticides by using linearity, accuracy, precision, and limits of detection and quantification. The linearity in the concentration ranged from 0.005 to 2.0 mg/kg ($R^2$ >0.999). Sample recoveries ranged from 80.2 to 98.3% with relative standard deviations below 4.0% for spiking levels from 0.01 to 1.0 mg/kg. The limits of detection ranged between 0.002 and 0.008 mg/kg, and the limits of quantification ranged between 0.006 and 0.027 mg/kg. The highest residue levels for carbendazim, thiabendazole, imazalil, and azoxystrobin in citrus fruits were 0.541, 0.958, 0.721, and 0.052 mg/kg, respectively. The pesticide residues found in citrus fruits were blow maximum residue limits (MRLs) and are not a serious public health problem.

• Analytical Science and Technology
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• v.18 no.3
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• pp.250-256
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• 2005

A selective method of high performance liquid chromatography with UV detector has been applied to determine 4 tetracycline antibiotics in the animal food, simultaneously. The targets were chlortetracycline (CTC), doxycycline (DC), oxytetracycline (OTC), and tetracycline (TC) that are used routinely in veterinary medicine for prevention and control of disease. Food samples were beef, pork, chicken, milk, whole egg, flatfish (Limanda yokohamae), jacopever (Sebastes hubbsi), seabream (Chrysophrys major), eel (Anguilla japonica) and lobster (Hommarus americanus). After extracting food samples with 20% trichloroacetic acid and McIlvaine buffer, they were purified by a $C_18$ SPE cartridge with 0.01M methanolic oxalic acid solution. The concentrated residue was re-dissolved in methanol, filtered, cleaned up and analyzed on a $C_18$ column. The mobile phase was a mixture of 0.01M oxalic acid and acetonitrile with a gradient ratio from 85:15 to 60:40. The UV wavelength was 365 nm. The overall recoveries were ranged from 71% to 98% and the limit of detections were 0.022 for CTC, 0.012 for DC and OTC and 0.009 mg/kg for TC at signal/noise > 3, respectively. As results, CTC, DC and TC were not detected in all selected food samples, however, OTC was detected in meat and fishes. The determined level of OTC was 0.04 ppm for pork, 0.17 ppm for flatfish and 0.05 and 0.08 ppm for jacopever, that were within the Maximum Residue Limits (MRLs) in the food.