• Journal of Radiation Protection and Research
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• v.42 no.3
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• pp.166-175
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• 2017

Background: This study presents food ingestion standards for radioactivity that can be applied in nuclear emergency exposure situations, and discusses the validity of the current domestic standards. Materials and Methods: This study derived food ingestion standards for radiocesium and radioiodine using domestic food intake rates and intervention levels, which serve as a basis for determining the necessity of public protective actions, and then compared them with the existing guidelines. Operational intervention levels were also derived using domestic food intake rates, and were compared with those of the International Atomic Energy Agency. Results and Discussion: The derived activity concentrations for food ingestion standards of radiocesium for infants were higher than those in the Act on Physical Protection and Radiological Emergency (APPRE) for all food categories, while for adults, the derived activity concentrations for drinking water and milk appeared to be slightly lower. The derived activity concentrations for vegetables, fruits, and grains were greater than those in the guidelines of the APPRE, while the derived activity concentrations for meat and seafood were similar to those in the APPRE. The derived activity concentrations for radioiodine were greater than both domestic and global standards. The calculated operational intervention levels (OILs) based on domestic food intake rates were greater than the IAEA's default OIL6 values for most radionuclides, except for a few ${\alpha}$-radionuclides. Conclusion: The current domestic guidelines turned out to be conservative overall, compared to the present results that were calculated using domestic food intake rates. It is recommended that the domestic guidelines should be revised and complemented transparently through an in-depth review by stakeholders on a solid scientific basis.

• Korean Journal of Environmental Biology
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• v.21 no.4
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• pp.321-327
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• 2003

Differences between the principles for the radiological protection of man and the environment are compared. The derived levels of exposure for man and biota recommended by the international agencies with dose rates for chronic radiation producing effects at different levels of biological organization were given in terms of the biological effects. Cytogenetic effects on plants after an exposure to ionizing radiation at low doses alone and in combination with other factors are discussed. A wide range of experimental data were analysed and the general conclusions were extracted to cover the topics such as non-linearity of dose response, synergistic and antagonistic effects of the combined exposure of different factors, radiation-induced genomic instability, and the phenomena of radioadaptation.

• The Korean Journal of Malacology
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• v.29 no.1
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• pp.43-50
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• 2013

We investigated the growth performance of oysters (initial shell height $57.5{\pm}8.5$ mm) under differing conditions of tidal exposure time and culture rack height in an experiment that commenced in April, 2011. Significant differences were observed in shell height from June 2011, in total weight from August, and in meat weight from September. Fatness tended to decrease during the experimental period, but was not significantly different at the end of the experiment. Significant differences in survival rates were mainly observed from June to August. After September, further changes were not observed in any experimental treatment group. The greatest growth potential ($L_{\infty}$) and survival rate were observed at a sea level of approximately 116 cm. The results indicate that in the study area the use of oyster culture conditions involving 1 or 2 h of tidal exposure and 60 - 70 cm rack height could result in oysters reaching the favored commercial half shell size within 14 months, with > 80% survival.

• The Korean Journal of Nuclear Medicine Technology
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• v.14 no.2
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• pp.65-76
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• 2010

Purpose: he use of PET scanners and the number of patient in Korea have been increased for recent several years dramatically. For this reason, technologists have more possibilities to be exposed to the radiation. The hospitals using PET scanners should make an effort to reduce the radiation exposure dose. The purpose of this study was to evaluate the radiation exposure does when using radiation shielding devices. The evaluation was performed through questionnaire survey and experiment. Materials and Methods: First, the technologists who had experience working in PET center in 2008-2009 were surveyed with questionnaire and TLD Figures, personal opinion of utilization of radiation shielding devices are analyzed. Second, we measured the shielding rate of shielding devices which have been using in PET study procedures. We divided the procedures into four steps; distribution, moving, injection of $^{18}F$-FDG and patient setup. Results: First, the results of this survey, using of L-block+Syringe shield, L-block, Syringe shield, No shield during the injection, were each 58.5%, 20%, 9%, 12.3%. The TLD values according to utilization of radiation shield, using both L-block+Syringe Shield and L-block showed the lower TLD values, and Syringe shield only or No shield showed the higher TLD values. Second, the results of experiments according to PET study procedures measured the shielding rates as follows. The shielding rates during the distribution using L-block, L-block+Apron shield were measured 97.4%, 97.7%. The shielding rates during the $^{18}F$-FDG delivery to the injection room using mobile Syringe shield, Syringe holder, Syringe shield carrier were each 81.7%, 98.9%, 99.7%. The shielding rates during the injection using Syringe shield, L-block, L-block+Syringe shield were measured each 51.9%, 98.3%, 98.7%. The shielding rates of Apron were measured in each 30, 60, 90, 120, 150 cm distance. The measurement were each 16.9%, 14.2%, 16.6%, 17.1%, 18.1%, 18.6%. Conclusion: The most effective method for radiation shielding is to using L-block during the $^{18}F$-FDG distribution and Syringe shield carrier during in moving $^{18}F$-FDG. For the $^{18}F$-FDG injection, L-block+Syringe shield have to be used. The shielding effect of Apron has shown average 16.4%. According to the survey of questionnaire, the operators recognized well risk of the radiation exposure but, tended ignore in working. The radiation dose according to recognition of radiation exposure risk was not relevant. but radiation dose according to utilization of radiation shield lower the more use it. The main reason of no use of shielding devices is cumbersome, 55% of the respondents answered. I'm sure, by use of radiation shield in all PET procedure, radiation exposure will be reduced considerably.

• Journal of Preventive Medicine and Public Health
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• v.47 no.1
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• pp.7-17
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• 2014

Risk assessment considers the situations and characteristics of the exposure environment and host. Various physiological variables of the human body reflects the characteristics of the population that can directly influence risk exposure. Therefore, identification of exposure factors based on the Korean population is required for appropriate risk assessment. It is expected that a handbook about general exposure factors will be used by professionals in many fields as well as the risk assessors of the health department. The process of developing the exposure factors handbook for the Korean population will be introduced in this article, with a specific focus on the general exposure factors including life expectancy, body weight, surface area, inhalation rates, amount of water intake, and soil ingestion targeting the Korean population. The researchers used national databases including the Life Table and the 2005 Time Use Survey from the National Statistical Office. The anthropometric study of size in Korea used the resources provided by the Korean Agency for Technology and Standards. In addition, direct measurement and questionnaire surveys of representative samples were performed to calculate the inhalation rate, drinking water intake, and soil ingestion.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.170-179
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• 2017

Objectives: This study aims to investigate the occupational radiation exposures of emergency medical technicians(EMTs) in emergency medical centers in Korea. The results will provide a basis for developing prevention programs to minimize adverse health effects relating to radiation exposure among emergency medical technicians working in this area. Methods: Radiation exposure doses were measured for twenty-two EMTs working in six emergency medical centers. Thermo Luminescent Dosimeters(TLD) were placed on three representative body parts, including chest, neck, and a finger. Measurements were conducted over the entire working hours of the participants for foor weeks. Dosimeters were analyzed according to a standard method by a KFDA-designated lab. Detection rate, annual radiation exposure dose, and relative levels to dose limit were derived based on the measured doses from the dosimeters. SPSS/Win 18.0 software(IBM, US) was used for statistical analysis. Results: Detection rates were 45.5%, 36.4%, and 45.5% for the dosimeters sampled from chest, neck, and a finger, respectively. The average annual doses were $2.39{\pm}3.44mSv/year$(range 0.38-10.0 mSv/year) for the chest, $2.72{\pm}3.05mSv/year$(2.00-11.34) for the neck, and $20.98{\pm}17.57mSv/year$(1.25-53.50) for the hand dose. The average annual eye dose was estimated to $3.61{\pm}2.37mSv/year$(1.50-8.34). The exposure dose levels of EMTs were comparable to those of radiologists, who showed relatively higher radiation dose among health care workers, as reported in another study. Conclusions: EMTs working in emergency medical centers are considered to be at risk of radiation exposure. Although the radiation exposure dose of EMTs does not exceed the dose limit, it is not negligible comparing to other professionals in health care sectors.

• Journal of Environmental Health Sciences
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• v.41 no.1
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• pp.1-10
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• 2015

Objectives: The purpose of this study was to propose an indirect exposure assessment method using a questionnaire survey at a time when direct exposure assessment would be impossible after a chemical accident. Methods: About two weeks after an accident, a questionnaire survey was performed with 1,264 persons from the local community. Variables related to exposure were extracted from the survey contents, weighted and then graded for comparison with subjective symptoms in order to evaluate the extent of exposure. Survey items suitable for reflecting the previous exposure level during the accident were extracted, weighted and divided into quartile ranges. Subjective symptoms showed an increasing tendency with higher exposure level when compared with final exposure level (p<0.01). Results: For the relationship between the final exposure grade and subjective symptoms, as the exposure grade was increasing the rates complaining of symptom also showed an increasing tendency. However, when adjusted for demographic characteristics, there was a tendency for the eye irritation symptom to appear higher in women, and respiratory organ irritation appeared higher in smokers. Conclusions: When the problem of recall bias is considered, this study may not have completely unraveled exposure and the characteristics of the participants can affect subjective symptoms. Nevertheless, the exposure rating method of using a questionnaire showed a significant relationship with symptom level. It can be deemed that assessment of past exposure may be successfully evaluated by questionnaire in cases such as chemical accidents.

• Journal of Environmental Health Sciences
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• v.21 no.1
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• pp.47-55
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• 1995

Minari(Oenanthe stolonifera DC.) lived in serious polluted water is able to remove chemical elements from batch system. This study attempted to compare the incorporation of cadmium and lead in batch system. Different concentrations of Cd(0.02 0.1 0.5 1.00 5.00 mg/l) and Pb(0.1 0.5 1.0 5.0 10.0 mg/l) were used. Toxic effects were obvious at Cd 1.00 mg/l and Pb 5.00 mg/l. The detrimental effects on minari were chlorosis of leaves and stunted roots and reduction in the number of lateral roots. There was reduction in growth rates exposed above Cd 1.00 mg/l and lead 5.0 mg/l. The minari capacities to remove Cd were 34.1-74.2% and Pb were 53.0~91.5%. The removal rates by minari in Cd and Pb solution were decreased with increased exposure concentration(in Cd r=0.97, in Pb r=0.88). The removal rates by minari in Cd and Pb solution were increased with increased growth rate(in Cd r=0.93 in Pb r=0.92). Recovery rates on minari are 67.3~95.2% in Cd water and 72.6~88.3% in Pb water. The rates are increased with increased growth rates and decreased initial concentrations.

• Journal of Environmental Health Sciences
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• v.46 no.3
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• pp.335-343
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• 2020

Objectives: The Korean Ministry of Environment has identified cases of people suspected of suffering lung disease potentially caused by polyhexamethylene guanidine (PHMG) used in humidifier disinfectants (HDs). Exposure assessment for the HDs was conducted using a questionnaire during face-to-face interview. The main purposes of this study were to develop a methodology to effectively classify levels of exposure to HDs based on a questionnaire. Methods: We first identified the overall participants' exposure characteristics by HD exposure levels; Second, we selected misclassified subjects and investigated characteristics of overestimated and underestimated subjects, focusing on exposure cases to PHMG-containing HDs. An inhalation reference concentration (RfC) for PHMG was produced on the basis of inhalation toxicity values. We made a cross-tabulation of the exposure classes (Exposure classes 1-to-4) by clinical classes based on the RfC. When the value of the exposure class minus the clinical class was 0 or 1, we assumed these were true values. When the value was ≥2 and ≤ -2, we assigned these cases to the overestimation group and underestimation group, respectively. Results: The overestimated group may have already recovered and responded excessively due to psychological anxiety or in order to receive compensation. On the other hand, relatively high mortality rates and surrogate responses for those under 10 years of age may have resulted in inaccurate exposure assessment for underestimated groups. For the characteristics of exposure, it was shown that for the underestimated group, the exposure was relatively weaker than the overestimated group, even though a high overall clinical rating was determined. Conclusions: This study may suggest ways to reduce bias and overcome the limitations of current HD exposure assessment.

• Journal of the Korean Society of Radiology
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• v.13 no.4
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• pp.667-674
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• 2019

Because examination with technegas produces images through simple diffusion accumulation, the examination room can become contaminated after scan. Therefore, radiation workers and patients awaiting examination will be affected by internal exposure from technegas inhalation. Before and after gravity ventilation, I am trying to find a way to reduce the exposure dose of waiting patients according to a comparative analysis of horizontal spatial dose rates over time. Spatial dose ratio were measured for 10 minutes from various distances and angles around ventilator's location before and after gravity ventilation. Then, mean values, standard deviation and reduction ratio were calculated. The highest reduction rate of gravity ventilation was 95.31% and the highest reduction ratio was 1 to 3 minutes. Therefore, the gravity ventilation could reduce the exposure dose of radiologic technologists, waiting patients, patient guardians and nurses. In conclusion, the reduction of the exposure dose during the technegas ventilation study through gravity ventilation will play a role in optimiging the protection and it is in accordance with the recommended reduction of the medical exposure by ICRP 103.