• Journal of Food Hygiene and Safety
• /
• v.39 no.2
• /
• pp.95-101
• /
• 2024

In this study, we investigated the migration level of items specified in the Korean Standards and Specifications for Utensils, Containers, and Packages (Ministry of Food and Drug Safety Notification) for 50 utensils and hygiene products made of biodegradable resins. Our results revealed that one Polylactide (PLA) baby tableware contained 20 mg/L in consumption of potassium permanganate, exceeding the standard of 10 mg/L or less. In all other samples, formaldehyde, lead (Pb), and arsenic (As) levels could be considered very safe and remained below the standard. Moreover, we tested the PLA baby tablewares (n = 21) for migration into a food simulant (4% v/v acetic acid) upon repeated elution at 100℃ for 30 min or UV irradiation for 2 h. We detected increased formaldehyde and As amounts at the repeated 100℃ treatment for 30 min compared to those upon repeated UV irradiation. However, the migration level was markedly low under both conditions. Furthermore, the Estimated Daily Intake (EDI) calculated on an infant-to-child basis from the formaldehyde and As migration at 100℃ for 30 min in the PLA sample was at the maximum value, i.e., 6.0×10^-4 mg/kg b.w./day and 1.3×10^-1 ㎍/kg b.w./day, corresponding to 0.40% and 10.42% of the Tolerable Daily Intake (TDI, 0.15 mg/kg b.w./day) and Provisional Tolerable Weekly Intake (PTWI, 9.0 ㎍/kg b.w./week), respectively. Therefore, in this study, we confirmed that biodegradable synthetic resins are safe to use for food.

• Journal of Sericultural and Entomological Science
• /
• v.25 no.1
• /
• pp.34-43
• /
• 1983

These studies have been carried out to find better locations for sericultural service regardless of the international silk market fluctuation in Korea. In order to acieve the purpose, various investigations and analyses have been carried out for more than four hundred sericultural communities to find out the main factors which caused to decrease in cocoon production in spite of a gloomy past silk market. Now, we believe that we have set up some fundamental guide lines in developing sound serviceable sericultural communities in Korea in case the government accepts the written advices, and the results obtained are as follows: 1. The Korean sericulture has been very prosperous from the 60's to the 70's. In 1976 the cocoon production was at its peak, reaching 41,704M/T from which its decline took place with annual averages of 18.5% for total cocoon production and 16.4% for mulberry field. These figures represent a quantitative decrease to one-third of the total amount in 1976. Since then, the Korean sericulture had continuously suffered from a shortage of raw silk resulting in a slow development of sericulture. At present, a steady development through all possible measures is great importance. 2. The downfall of the korean sericulture resulted from two factors of such as the external, which led to the decline in the price of raw silk at the international market and restrain of import and, the internal, resulting in the little increase of cocoon price and a comparatively lower benefits from the sericulture than from other cash crops. 3. The already established sericultural zone collapsed and then reorganized with the outstanding regional specialization so the decline in total cocoon production in the country. Based on the agricultural regions, 1980 cocoon production was very stable in the mountaineaus area of the east-south which used with intercropping. In this area there was small decline of 33% compare with that of the 1979, and with 70% decline in the dry field farming area of Kangwon Do. In an administrative districtwise, six counties beginning with Sanchnung county of Kyungsang Nam Do, showed less than 20% decline of cocoon production, sixteen counties beginning with Samchuck county of Kangwon Do marked above 80% decrease of cocoon production. In the smaller unit area-wise, there was a big difference among them. twenty-five myons rather increased and a hundrd fourty-three myons decreased above 80% of it. 4. The cocoon production was positively correlated with the decreasing percentage of cocoon production per household. It was also affected by the ratio of the mulberry field area to the total cultivated area per household and cocoon productivity per 10a. 5. Four hundred sixty-four villages in the seventeen counties were surveyed on the basis of farm management and techniques concerned ('80/'79), and then the results were evaluated by using of computer. These results are summarized as foolows: (1) Cocoon production per household There was no difference among the agricultural regions in cocoon production. The cocoon production per household in the comparatively stable villages increased from 100.8kg in 1979 to 122kg in 1981. Cocoon yield in the stable villages decreased by 20% of '81/'79. The cocoon production per house hold in while that of the unstable villages decreased by more than 40% from 102.9kg in 1979 to 82kg in 1981. (2) Cocoon yield per 10a mulberry field The cocoon yield per 10a was higher in the plain area than in the mountaineous area. The stable villages had an average of 73.4kg cocoon yield/10a while the unstabe ones had only an average of 55kg. (3) Adoption the mulberry branch rearing method The branch rearing method was more popular in the plain area than in the mountainous area. In the stable vilages adopted 24.2% in spring and 16.7% in autumn of 1979. In 1981 it shwed increases of 34.3% and 10.1% in the two seasons respectivly. However, the unstable villages showed 13.3% and 126% in both seasons, respectively. (4) The patterns of the combined management system in the sericultural farming The popular management system in the sericultural from was combined with rice and other cash crops, showing 55% of the total households surveyed. Fourteen percent of the households combined the management system with rice and other cash crops and 14% of the households combined with rice only. The villages wich earned less than 20% of the total income from the sericulture reached 81% of the total houscholds indicating that they were still far beyond a complete combination system. (5) Damage by agricultural chemicals The damage caused by agricultural chemicals was mainly due to the protection of rice against insectpests and diseases in the plain areas and took place mostly in the autumn season. The chemicals applied was 65% of Iiquid and 35% of powder forms and 35% of damage was from granulat form of the chemicals. The use of the granular chemicals was low because of high cost.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.3
• /
• pp.250-258
• /
• 1999

The purpose of this study was to compare heavy metal concentrations in uncontaminated soil with those in soil influenced by industrial activities, and to investigate the relationship between change of heavy metal content and the kind of industry at the Iksan 2nd Industrial Complex that has started since 1995. Soils sampled in 0-3 cm and 3-6 cm soil depth, respectively were analized for content of Cd, Cu, Ni, Pb and Zn. The content of Cd in soil layer of 0 to 3 cm was 0.07-4.37ppm range, average concentration was 0.516ppm and 3-6 cm was 0.07-8.52ppm range, average concentration was 0.380ppm. Area of the chemicals, dyes and metal products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Cu in soil layer of 0 to 3 cm was 0.61-42.62ppm range, average concentration was 11.087ppm and 3-6 cm was 0.16-35.45ppm range, average concentration was 7.578ppm. Area of the metal products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Ni in soil layer of 0 to 3 cm was 0.19-15.93ppm range, average concentration was 5.525ppm and 3-6 cm was 0.39-15.59ppm range, average concentration was 5.310ppm. Area of the metal and chemical products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Pb in soil layer of 0 to 3 cm was 3.10-55.75ppm range, average concentration was 23.543ppm and 3-6 cm was 3.35-46.55ppm range, average concentration was 19.198ppm. Area of the chemicals and metal products manufacturing were higher than the other manufacturing area in Industrial Complex. The content of Zn in soil layer of 0 to 3 cm was 26.50-943.00ppm range, average concentration was 158.329ppm and 3-6 cm was 35.45-882.45ppm range, average concentration was 127.914ppm. Area of the chemicals and metal products manufacturing were higher than the other manufacturing area in Industrial Complex. As the result, this study was to compare Cd, Cu, Ni, Pb, Zn average concentration in uncontaminated soil of world with those in soil, that Cu, Ni were uncontaminated concentration level, Cd was somewhat higher compare with the concentration level of world, Pb and Zn were very higher. Soil contaminated degree of Iksan 2nd Industrial Complex was known a difference by type of industrial activities(chemical, dyes and metal of products)

• The Korean Journal of Nuclear Medicine Technology
• /
• v.14 no.2
• /
• pp.26-32
• /
• 2010

Purpose: It is to find the way to minimize occupationally exposed dose for workers in vivo tests in each working stage within the range of the working environment which does not ruin the examination and the performance efficiency. Materials and Methods: The process of the nuclear tests in vivo using a radioactive isotope consists of radioisotope distribution, a radioisotope injection ($^{99m}Tc$, $^{18}F$-FDG), and scanning and guiding patients. Using a measuring instrument of RadEye-G10 gamma survey meter (Thermo SCIENTIFIC), the exposure doses in each working stage are measured and evaluated. Before the radioisotope injection the patients are explained about the examination and educated about matters that require attention. It is to reduce the meeting time with the patients. In addition, workers are also educated about the outside exposure and have to put on the protected devices. When the radioisotope is injected to the patients the exposure doses are measured due to whether they are in the protected devices or not. It is also measured due to whether there are the explanation about the examination and the education about matters that require attention or not. The total exposure dose is visualized into the graph in using Microsoft office excel 2007. The difference of this doses are analyzed by wilcoxon signed ranks test in using SPSS (statistical package for the social science) program 12.0. In this case of p<0.01, this study is reliable in the statistics. Results: It was reliable in the statistics that the exposure dose of injecting $^{99m}Tc$-DPD 20 mCi in wearing the protected devices showed 88% smaller than the dose of injecting it without the protected devices. However, it was not reliable in the statistics that the exposure dose of injecting $^{18}F$-FDG 10 mCi with wearing protected devices had 26% decrease than without them. Training before injecting $^{99m}Tc$-DPD 20 mCi to patient made the exposure dose drop to 63% comparing with training after the injection. The dose of training before injecting $^{18}F$-FDG 10 mCi had 52% less then the training after the injection. Both of them were reliable in the statistics. Conclusion: In the examination of using the radioisotope $^{99m}Tc$, wearing the protected devices are more effective to reduce the exposure dose than without wearing them. In the case of using $^{18}F$-FDG, reducing meeting time with patients is more effective to drop the exposure dose. Therefore if we try to protect workers from radioactivity according to each radioisotope characteristic it could be more effective and active radiation shield from radioactivity.

• The Journal of Korean Society for Radiation Therapy
• /
• v.31 no.1
• /
• pp.33-41
• /
• 2019

Purpose : To evaluate the effectiveness of Jaw-tracking(JT) technique in Intensity-modulated radiation therapy(IMRT) and Volumetric-modulated arc therapy(VMAT) for radiation therapy of esophageal cancer by analyzing volume dose of perimetrical normal organs along with the low-dose volume regions. Materials and Method: A total of 27 patients were selected who received radiation therapy for esophageal cancer with using $VitalBeam^{TM}$(Varian Medical System, U.S.A) in our hospital. Using Eclipse system(Ver. 13.6 Varian, U.S.A), radiation treatment planning was set up with Jaw-tracking technique(JT) and Non-Jaw-tracking technique(NJT), and was conducted for the patients with T-shaped Planning target volume(PTV), including Supraclavicular lymph nodes(SCL). PTV was classified into whether celiac area was included or not to identify the influence on the radiation field. To compare the treatment plans, Organ at risk(OAR) was defined to bilateral lung, heart, and spinal cord and evaluated for Conformity index(CI) and Homogeneity index(HI). Portal dosimetry was performed to verify a clinical application using Electronic portal imaging device(EPID) and Gamma analysis was performed with establishing thresholds of radiation field as a parameter, with various range of 0 %, 5 %, and 10 %. Results: All treatment plans were established on gamma pass rates of 95 % with 3 mm/3 % criteria. For a threshold of 10 %, both JT and NJT passed with rate of more than 95 % and both gamma passing rate decreased more than 1 % in IMRT as the low dose threshold decreased to 5 % and 0 %. For the case of JT in IMRT on PTV without celiac area, $V_5$ and $V_{10}$ of both lung showed a decrease by respectively 8.5 % and 5.3 % in average and up to 14.7 %. A $D_{mean}$ decreased by $72.3{\pm}51cGy$, while there was an increase in radiation dose reduction in PTV including celiac area. A $D_{mean}$ of heart decreased by $68.9{\pm}38.5cGy$ and that of spinal cord decreased by $39.7{\pm}30cGy$. For the case of JT in VMAT, $V_5$ decreased by 2.5 % in average in lungs, and also a little amount in heart and spinal cord. Radiation dose reduction of JT showed an increase when PTV includes celiac area in VMAT. Conclusion: In the radiation treatment planning for esophageal cancer, IMRT showed a significant decrease in $V_5$, and $V_{10}$ of both lungs when applying JT, and dose reduction was greater when the irradiated area in low-dose field is larger. Therefore, IMRT is more advantageous in applying JT than VMAT for radiation therapy of esophageal cancer and can protect the normal organs from MLC leakage and transmitted doses in low-dose field.