• Title, Summary, Keyword: ingestion pathway

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Nuclides Transport Analysis and Dose Calculation Using Dynamic Model for Rice Ingestion Pathway (쌀 섭취경로에서 동적모델을 사용한 장반감기핵종의 거동해석 및 내부피폭 선량계산)

  • Lee, Chang-Woo;Choi, Yong-Ho;Hwang, Won-Tae;Lee, Jeong-Ho
    • Journal of Radiation Protection and Research
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    • v.17 no.2
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    • pp.15-23
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    • 1992
  • Transport behaviors of Cs-137 and Sr-90 were analyzed and ingestion doses were calculated using dynamic model for rice field-rice-man pathway. Cs-137 binding strongly to soil remain longer in rice field than Sr-90. Foliar deposition on rice plant during growing period is the main contamination mechanism.

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Analysis of Exposure Pathways and the Relative Importance of Radionuclides to Radiation Exposure in the Case of a Severe Accident of a Nuclear Power Plant (원전 중대사고시 피폭경로 및 핵종의 방사선 피폭에 대한 상대적 중요도 해석)

  • Hwang, Won-Tae;Suh, Kyung-Suk;Kim, Eun-Han;Han, Moon-Hee;Kim, Byung-Woo
    • Journal of Radiation Protection and Research
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    • v.19 no.3
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    • pp.209-221
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    • 1994
  • In the case of a severe accident of a nuclear power plant, the whole body dose and the relative importance of the radionuclides during the lifetime of an exposed person were estimated for each exposure pathway with distances from the release point. The external exposure pathways due to immersion of radioactive cloud and deposition of radioactive materials on the ground, and the internal exposure pathways due to inhalation and ingestion of contaminated foodstuffs were considered. The effects due to the ingestion of contaminated foodstuffs were estimated considering the variation of radioactive concentration in the foodstuffs according to deposition time and elapsed time after deposition using a dynamic ingestion pathway model applicable to Korean environment, named 'KORFOOD'. As the results up to 80 km from the release point, the effects due to ingestion of contaminated foodstuffs showed the highest contribution to total exposure dose. The contribution of I isotopes was the highest in the case of the external dose due to immersion of radioactive cloud and internal dose due to inhalation. The contribution of Cs isotopes was highest in the case of the external dose due to deposition of radioactive materials on the ground. In the case of the internal dose due to ingestion of contaminated foodstuffs, Cs deposition in summer and Sr deposition in winter, respectively, were the most dominant radionuclide to whole body.

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Parameter Uncertainty and Sensitivity Analysis on a Dose Calculation Model for Terrestrial Food-Chain Pathway (육상식품 섭취경로에 의한 선량계산 모델에서 파라메터의 불확실성 및 민감도 분석)

  • Lee, Chang-Woo;Choi, Yong-Ho;Chun, Ki-Jung;Lee, Jeong-Ho
    • Journal of Radiation Protection and Research
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    • v.16 no.2
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    • pp.67-74
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    • 1991
  • Parameter uncertainty and sensitivity of KFOOD model for calculating the ingestion dose via terrestrial food-chain pathway was analyzed with using Monte-Carlo approach. For the rice ingestion pathway, estimated values from KFOOD code were very conservative. Most sensitive input parameters in model were deposition velocities and soil-to-plant transfer coefficient of radionuclides.

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Health Risk Assessment of Lead Exposure through Multi-pathways in Korea (납의 다경로 노출에 의한 건강위해성평가 : 우리 나라 일부 지역 성인들을 대상으로)

  • Chung, Yong;Hwang, Man-Sik;Yang, Ji-Yeon;Jo, Seong-Joon
    • Environmental health and toxicology
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    • v.14 no.4
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    • pp.203-216
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    • 1999
  • This paper describes a set of multi-pathway models for estimating health risk to lead. The models link concentrations of an environmental contaminant (lead) in air, water and food to human exposure through inhalation, ingestion, and dietary routes. Exposure is used as the foundation for predicting risk of health detriment within the population. The process of estimating exposure using often limited data and extrapolating to a large diverse population requires many assumption, inferences, and simplification. This paper is divided into four section. The first section provides lead contaminant levels on obtaining environmental concentration of air, tap water, and foods. The second section provides a discussion of exposure parameters and uncertainty associated predicting human health risk of contaminants. The third and fourth section illustrate lifetime average daily exposure (LADE) and excess cancer risk (ECR) based on exposure parameters. The relationship between concentration of lead in an environmental medium and human exposure is determined with pathway exposure factors (PEFs). The calculation of LADE and ECR is carried out using Monte-Carlo simulation with probability density function of exposure parameters. Examination of the result reveals that, for lead exposure, ingestion (food) is the dominant route of exposure rather than inhalation (air), and ingestion (tap eater).

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A Study on the Assessment of Derived Intervention Levels in Foodstuffs Using the Dynamic Ingestion Pathway Model (동적 섭식경로모델을 이용한 음식물에 대한 유도 방사능 개입준위의 산정에 관한 연구)

  • Hwang, Won-Tae;Han, Moon-Hee;Kim, Byung-Woo
    • Journal of Radiation Protection and Research
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    • v.19 no.3
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    • pp.199-208
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    • 1994
  • The derived intervention levels in Korean foodstuffs were estimated using the dynamic ingestion pathway model which was developed considering Korean environment. The derived intervention levels were estimated from the intervention level of dose based on the thyroid committed dose equivalent of infant in the case of I-131, and the whole body committed dose equivalent for age groups and 13 kinds foodstuffs in the cases of Cs-137 and Sr-90. The derived intervention levels were shown as a considerable variation with deposition time and radionuclide. The adult was the most important age group in the estimation of derived intervention levels for Cs-137 and Sr-90. In the adult, the derived intervention levels for rice were 2390 and 47 Bq/kg for Cs-137 and Sr-90 in the case of deposition in summer, respectively, and 198 and 79 Bq/kg in the case of deposition in winter, respectively.

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Stabilization of fluorine in soil using calcium hydroxide and its potential human health risk

  • Jeong, Seulki;Kim, Doyoung;Yoon, Hye-On
    • Environmental Engineering Research
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    • v.24 no.4
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    • pp.654-661
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    • 2019
  • This study assessed the stabilization of fluorine (F)-contaminated soil using calcium hydroxide (Ca(OH)2) and the consequent changes in human health risk. The bioavailable F decreased to 3.5%, (i.e., 57.9 ± 1.27 mg/kg in 6% Ca(OH)2-treated soil sample) from 43.0%, (i.e., 711 ± 23.4 mg/kg in control soil sample). This resulted from the conversion of water-soluble F to stable calcium fluoride, which was confirmed by XRD spectrometry. Soil ingestion, inhalation of fugitive dust from soil, and water ingestion were selected as exposure pathways for human health risk assessment. Non-carcinogenic risks of F in soils reduced to less than 1.0 after stabilization, ranging from 4.2 to 0.34 for child and from 3.0 to 0.25 for adult. Contaminated water ingestion owing to the leaching of F from soil to groundwater was considered as a major exposure pathway. The risks through soil ingestion and inhalation of fugitive dust from soil were insignificant both before and after stabilization, although F concentration exceeded the Korean soil regulatory level before stabilization. Our data suggested that substantial risk to human health owing to various potential exposure pathways could be addressed by managing F present in soil.

Identification of a neural pathway governing satiety in Drosophila

  • Min, Soohong;Chung, Jongkyeong
    • BMB Reports
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    • v.49 no.3
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    • pp.137-138
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    • 2016
  • Satiety cues a feeding animal to cease further ingestion of food, thus protecting it from excessive energy gain. Impaired control of satiety is often associated with feeding-related disorders such as obesity. In our recent study, we reported the identification of a neural pathway that expresses the myoinhibitory peptide (MIP), critical for satiety responses in Drosophila. Targeted silencing of MIP neuron activity strikingly increased the body weight (BW) through elevated food intake. Similarly, genetic disruption of the gene encoding MIP also elevated feeding and BW. Suppressing the MIP pathway behaviorally transformed the satiated flies to feed similar to the starved ones, with augmented sensitivity to food. Conversely, temporal activation of MIP neuron markedly reduced the food intake and BW, and blunted the sensitivity of the starved flies to food as if they have been satiated. Shortly after termination of MIP neuron activation, the reduced BW reverted to the normal level along with a strong feeding rebound. Together our results reveal the switch-like role of the MIP pathway in feeding regulation by controlling satiety.

Assessment of health risk associated with arsenic exposure from soil, groundwater, polished rice for setting target cleanup level nearby abandoned mines

  • Lee, Ji-Ho;Kim, Won-Il;Jeong, Eun-Jung;Yoo, Ji-Hyock;Kim, Ji-Young;Lee, Je-Bong;Im, Geon-Jae;Hong, Moo-Ki
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.1
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    • pp.38-47
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    • 2011
  • This study focused on health risk assessment via multi-routes of As exposure to establish a target cleanup level (TCL) in abandoned mines. Soil, ground water, and rice samples were collected near ten abandoned mines in November 2009. The As contaminations measured in all samples were used for determining the probabilistic health risk by Monte-Carlo simulation techniques. The human exposure to As compound was attributed to ground water ingestion. Cancer risk probability (R) via ground water and rice intake exceeded the acceptable risk range of $10^{-6}{\sim}10^{-4}$ in all selected mines. In particular, the MB mine showed the higher R value than other mines. The non-carcinogenic effects, estimated by comparing the average As exposure with corresponding reference dose were determined by hazard quotient (HQ) values, which were less than 1.0 via ground water and rice intake in SD, NS, and MB mines. This implied that the non-carcinogenic toxic effects, due to this exposure pathway had a greater possibility to occur than those in other mines. Besides, hazard index (HI) values, representing overall toxic effects by summed the HQ values were also greater than 1.0 in SD, NS, JA, and IA mines. This revealed that non-carcinogenic toxic effects were generally occurred. The As contaminants in all selected mines exceeded the TCL values for target cancer risk ($10^{-6}$) through ground water ingestion and rice intake. However, the As level in soil was greater than TCL value for target cancer risk via inadvertent soil ingestion pathway, except for KK mine. In TCL values for target hazard quotient (THQ), the As contaminants in soil did not exceed such TCL value. On the contrary, the As levels in ground water and polished rice in SD, NS, IA, and MB mines were also beyond the TCL values via ground water and rice intake. This study concluded that the health risks through ground water and rice intake were greater than those though soil inadvertent ingestion and dermal contact. In addition, it suggests that the abandoned mines to exceed the risk-based TCL values are carefully necessary to monitor for soil remediation.

A Calculation of Effective Dose Equivalent from Data of Environmental Monitoring around the Karlsruhe Nuclear Research Center (Karlsruhe 원자력연구소 주변의 환경방사능 측정자료로부터 실효선량당량계산)

  • Lee, Chang-Woo;Lee, Jeong-Ho;Wicke, A.
    • Journal of Radiation Protection and Research
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    • v.15 no.2
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    • pp.75-85
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    • 1990
  • The dose calculations were carried out using environmental montoring data around Karlsruhe Nuclear Research Center(KfK). Ingestion of plant foods was the most important pathway, and the K-40 and Pb-210 natural radioisotopes in food were the most effective radiation source to man. The dose received from artificial nuclides were mostly emitted by gamma irradiation of Cs-134 and Cs-137 deposited on the ground. The effective dose equivalent in the KfK environment was far less than the dose equivalent limit recommended by ICRP.

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A Pathway Analysis Model for Determining Acceptable Levels of Contamination of Radionuclides in Soil (토양의 방사능오염 허용기준치 설정을 위한 피폭경로모델)

  • Lee, Chang-Woo;Kim, Kug-Chan;Lee, Jeong-Ho
    • Journal of Radiation Protection and Research
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    • v.15 no.2
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    • pp.67-74
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    • 1990
  • A methodology for calculating acceptable levels of contamination of radionuclides in soil for unrestricted use was described. Pathways of exposure include direct radiation from ground surfaces, ingestion of contaminated food and inhalation of resuspended radionuclides. Results calculated using site-specific data for Korean environment were discussed and compared with those estimated by other guidelines.

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