• 한국지하수토양환경학회지:지하수토양환경
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• 제20권6호
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• pp.1-7
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• 2015

The most critical health effect of lead exposure is the neurodevelopmental effect to children caused by the increased blood lead level. Therefore, the endpoint of the risk assessment for lead-contaminated sites should be set at the blood lead level of children. In foreign countries, the risk assessment for lead-contaminated sites is conducted by estimating the increased blood lead level of children via oral intake and/or inhalation (United States Environmental Protection Agency, USEPA), or by comparing the estimated oral dose to the threshold oral dose of lead, which is derived from the permissible blood lead level of children (Dutch National Institute for Public Health and the Environment, RIVM). For the risk assessment, USEPA employs Integrated-Exposure-Uptake-Biokinetic (IEUBK) Model to check whether the estimated portion of children whose blood lead level exceeds 10 µg/dL, threshold blood lead level determined by USEPA, is higher than 5%, while Dutch RIVM compares the estimated oral dose of lead to the threshold oral dose (2.8 µg/kg-day), which is derived from the permissible blood lead level of children. In Korea, like The Netherlands, risk assessment for lead-contaminated sites is conducted by comparing the estimated oral dose to the threshold oral dose; however, because the threshold oral dose listed in Korean risk assessment guidance is an unidentified value, it is recommended to revise the existing threshold oral dose described in Korean risk assessment guidance. And, if significant lead exposure via inhalation is suspected, it is useful to employ IEUBK Model to derive the risk posed via multimedia exposure (i.e., both oral ingestion and inhalation).

• 한국입자에어로졸학회지
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• 제14권4호
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• pp.97-105
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• 2018

Recently, people's interest in particulate matter (PM) has been increasing, due to its hazardous health effects. The purpose of this study was to investigate the concentrations and as well as the inhaled weight of PM, correlated with person's heart rate in subway, bus, vehicle and bicycle in the major public transportation (Sadang - Jamsil and Nowon - Dongdaemun) in Seoul. The concentration of $PM_{10}$ and $PM_{2.5}$ were measured from each of transportation means and calculated the average concentrations which were 87.2 and $57.8{\mu}g/m^3$ for subway, 62.8 and $42.5{\mu}g/m^3$ for vehicle, 61.5 and $36.8{\mu}g/m^3$ for bus and 53.0 and $29.4{\mu}g/m^3$ for bicycle in $PM_{10}$ and $PM_{2.5}$ respectively. Inhalation dose for $PM_{10}$ and $PM_{2.5}$ were estimated at 248.1 and $139.4{\mu}g$ for bicycle, 56.7 and $39.3{\mu}g$ for vehicle, 49.4 and $29.9{\mu}g$ for bus and 44.3 and $29.1{\mu}g$ for subway, respectively. Even though subway had the highest concentration, the highest inhalation dose was the bicycle. It was due to the long travel time-exposure and breathing rate which leads to maximum of $PM_{10}$ 5.6 and $PM_{2.5}$ with 4.8 times inhalation dose comparing with other modes of transportation. With regards to future studies, the amount of inhalation in each transportation means should be considered in risk assessments of PM.

• 동의생리병리학회지
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• 제16권1호
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• pp.78-88
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• 2002

Experimental animals were divided into 5 groups; normal, cadmium control, and 3 experimental groups. Cadmium control and experimental groups were exposed to 1 mg/㎥ of cadmium aerosol in air by inhalation exposure for 6 hours/day, 5 days/week during 4 weeks. Dosages of 20, 40, and 80mg/kg of extracts of persimmon leaves were intraperitoneally injected to experimental groups respectively and several toxicological parameters and induction of metallothionein were measured from the rats that inhaled cadmium aerosol in air. The results of this study were as follows. Cadmium concentration that cadmium control and experimental groups were inhaled was 0.980±0.061 mg/㎥. Mass median diameter of cadmium aerosol for inhalation exposure was 4.93±0.483㎛. Cadmium content of normal group in lung was 0.088㎍/g and the highest cadmium content in lung, 55.492㎍/g was from 80mg/kg dose group. Cadmium concentration of normal group in blood was 0.348㎍/100㎖ and the highest cadmium concentration in blood, 2.642㎍/100㎖ was from cadmium control. Cadmium concentration of normal group in liver was 0.010㎍/g and the highest cadmium concentration in liver, 31.100㎍/g was from 20mg/kg dose group. Cadmium concentration of normal group in kidney was 0.030㎍/g and the highest cadmium concentration in kidney, 2.526㎍/g was from cadmium control. Cadmium concentration of normal group in intestine was O.064㎍/g and the highest cadmium concentration in intestine, 0.300㎍/g was from 80mg/kg dose group. The highest cadmium concentration in urine by week was 6.080㎍/day from 20mg/kg dose group in the fouth week and the highest cadmium concentration in feces by week was 341.731㎍/day from 20mg/kg dose group in the fouth week. Metallothionein concentration of normal group in lung was 5.769㎍/g and the highest in lung, 30.986㎍/g was from 80mg/kg dose group. Metallothionein concentration of normal group in liver was 38.856㎍/g and the highest in liver, 169.378㎍/g was from 40mg/kg dose group. Metallothionein concentration of normal group in kidney was 22.228㎍/g and the highest in kidney, 47.898㎍/g was from 80mg/kg dose group. Metallothionein concentration of normal group in intestine was 2.170㎍/g and the highest in intestine, 13.642㎍/g was from 80mg dose group.

• Journal of Radiation Protection and Research
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• 제48권2호
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• pp.59-67
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• 2023

Background: This study aims to reevaluate natural radiation exposure, following up on our previous study conducted in 2019, and to assess the associated risk of lung cancer to the public residing in the gold mining areas of Betare-Oya, east Cameroon, and its vicinity. Materials and Methods: Gamma-ray spectra collected using a 7.62 cm×7.62 cm in NaI(Tl) scintillation spectrometer during a car-borne survey, in situ measurements and laboratory measurements performed in previous studies were used to determine the outdoor absorbed dose rate in air to evaluate the annual external dose inhaled by the public. For determining internal exposure, radon gas concentrations were measured and used to estimate the inhalation dose while considering the inhalation of radon and its decay products. Results and Discussion: The mean value of the laboratory-measured outdoor gamma dose rate was 47 nGy/hr, which agrees with our previous results (44 nGy/hr) recorded through direct measurements (in situ and car-borne survey). The resulting annual external dose (0.29±0.09 mSv/yr) obtained is similar to that of the previous study (0.33±0.03 mSv/yr). The total inhalation dose resulting from radon isotopes and their decay products ranged between 1.96 and 9.63 mSv/yr with an arithmetic mean of 3.95±1.65 mSv/yr. The resulting excess lung cancer risk was estimated; it ranged from 62 to 216 excess deaths per million persons per year (MPY), 81 to 243 excess deaths per MPY, or 135 excess deaths per MPY, based on whether risk factors reported by the U.S. Environmental Protection Agency, United Nations Scientific Committee on the effects of Atomic Radiation, or International Commission on Radiological Protection were used, respectively. These values are more than double the world average values reported by the same agencies. Conclusion: There is an elevated level of risk of lung cancer from indoor radon in locations close to the Betare-Oya gold mining region in east Cameroon. Therefore, educating the public on the harmful effects of radon exposure and considering some remedial actions for protection against radon and its progenies is necessary.

• Nuclear Engineering and Technology
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• 제54권1호
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• pp.293-300
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• 2022

During the decommissioning of the nuclear facilities, the radioactive gases in pressure vessels may leak due to the demolition operations. The decommissioning site has large space, slow air circulation, and many large nuclear facilities, which increase the difficulty of workers' inhalation exposure assessment. In order to dynamically evaluate the activity distribution of radionuclides and the committed effective dose from inhalation in nuclear decommissioning environment, an inhalation exposure assessment method based on the modified eddy-diffusion model and the inhaled dose conversion factor is proposed in this paper. The method takes into account the influence of building, facilities, exhaust ducts, etc. on the distribution of radioactive gases, and can evaluate the influence of radioactive gases diffusion on workers during the decommissioning of nuclear facilities.

• 대한방사성의약품학회지
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• 제3권1호
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• pp.18-24
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• 2017

Patient-specific image-based internal dosimetry involves using the patient's individual anatomy and spatial distribution of radioactivity over time to obtain an absorbed dose calculation. Individual absorbed dose was calculated by accumulated activity multiply S-value of each organs. The aim of this study was to calculate the S-values using Monte Carlo simulation in monkey and mouse and evaluation of absorbed dose in each organ. Self-irradiation S-value of monkey heart self-irradiation was 3.15E-03 mGy-g/MBq-s, lung self-irradiation was 8.94E-04 mGy-g/MBq-s and liver self-irradiation S-value was 2.23E-03 mGy-g/MBq-s. Mouse heart self-irradiation S-value was 1.95E-01 mGy-g/MBq-s, lung was 9.59E-02 mGy-g/MBq-s, and liver was 1.40E-03 mGy-g/MBq-s. The results of this study show that the calculation protocol of image based individual absorbed dose of each organ using Monte Carlo simulation. Therefore, this study may be applied to calculate human specific absorbed dose.

• Toxicological Research
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• 제24권2호
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• pp.119-127
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• 2008

The objectives of this study were to examine the lung injury and inflammation caused by manual metal arc stainless steel(MMA-SS) welding fume inhalation and to evaluate the recovery process. Sprague-Dawley rats were exposed to MMA-SS welding fumes for 2 h per day in a whole-body exposure chamber, with a total suspended particulate(TSP) concentration of $51.4{\pm}2.8mg/m^3$(low dose) or $84.6{\pm}2.9mg/m^3$(high dose) for 30 days. The animals were sacrificed after 30 days of exposure as well as after a 30-day recovery period. To assess the inflammatory or injury responses, cellular and biochemical parameters as well as cytokines were assayed in the bronchoalveolar lavage fluid(BALF). MMA-SS welding fume exposure led to a significant elevation in the number of alveolar macrophages(AM) and polymorphonuclear cells(PMN). Additionary, the values of $\beta$-n-acetyl glucosaminidase($\beta$-NAG) and lactate dehydrogenase(LDH) in the BALF were increased in the exposed group when compared to controls. After 30 days of recovery from exposure, a significant reduction in inflammatory parameters of BALF was observed between the exposed and recovered groups. Slight, but significant elevations were noted in the number of AM and PMN in the recovered groups, and AM that had been ingested fume particles still remain in the lungs. In conclusion, these results indicated that welding fumes induced inflammatory responses and cytotoxicity in the lungs of exposed rats. Fume particles were not fully cleared from lungs even after a 30-day recovery period.

• Journal of Radiation Protection and Research
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• 제31권3호
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• pp.135-140
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• 2006

비밀봉 방사성물질의 취급 사고시 방사성핵종은 흡입과 취식의 두 가지 경로로 섭취될 수 있다. 이때 일상 감시처럼 하나의 섭취경로만 가정하여 예탁유효선량을 평가하면 심각한 오차를 유발할 수 없다. 이러한 잠재 오차를 제시하기 위해 총 섭취에 대한 흡입섭취의 비율을 달리할 때 예탁유효선량의 변동을 분석하였다. $^{241}Am$(AMAD 5 ${\mu}m$, 흡수형 M)을 대상으로 핵종의 생물역동학적 모델과 데이터를 이용하여 여러 흡입섭취 분율에서 폐, 소변 및 대변에 대한 바이오어세이 측정치를 모의하였다. 섭취 3일 후 예상 측정치를 이용하고 단일 경로 섭취를 가정한 경우 평가된 예탁유효선량의 잠재 오차는 -100%에서부터 많게는 +34,000%에 이르는 것으로 나타났다. 흡입섭취가 있을 때 대변만 분석하면 큰 오차가 발생하였다. 섭취경로 오판에 따르는 선량평가의 오차를 줄이기 위해 두 종류의 바이오어세이를 이용하는 전략을 제안하였다.

• 동의생리병리학회지
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• 제18권2호
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• pp.474-483
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• 2004

To know the effects between Cd inhalation toxicity and extract of Radix Achyranthis Bidentatae, 4 rat groups were exposed to Cd aerosol in air using whole-body inhalation exposure for 6 hours/day, 5 days/week, and 4 weeks. Cd concentration in air was 1.03㎎/㎥ and mass median diameter(MMD) was 1.69㎛. 3 different dose intraperitoneal injections of extract of Radix Achyranthis Bidentatae to 3 inhalation exposure groups was done for 4 weeks and the results were as follows: The highest body weight gain for 4 weeks and food intake per day were from inhalation exposure group I and the highest lung and liver weight were also from inhalation exposure group I. The highest kidney weight was from inhalation exposure group III. The lowest Cd content in lung was 33.49㎍/g from inhalation exposure group I. The lowest Cd concentration in blood was 9.36㎍/㎗ from inhalation exposure control. Cd concentrations of 40.02㎍/g in liver and 69.18㎍/g in kidney were the lowest from inhalation exposure group I and III, respectively. The lowest Cd concentration in liver was 21.08㎍/g from inhalation exposure group III and The lowest Cd concentration in kidney was 15.78㎍/g from inhalation exposure group II. For weekly Cd concentration in urine, the value of the fourth week from inhalation exposure group III was the highest. For weekly Cd concentration in feces, the value of the first week from inhalation exposure group III was the highest. The highest metallothionein concentration in lung was 53.42 ㎍/g from inhalation exposure group III and the highest metallothionein concentration in liver was 188.18㎍/g from inhalation exposure group III. The highest metallothionein concentration in kidney was 143.92㎍/g from inhalation exposure group III. The highest Hct, Hb, and WBC values were from inhalation exposure group II and the highest RBC value was from inhalation exposure group III.

• Journal of Radiation Protection and Research
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• 제16권1호
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• pp.1-13
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• 1991

국내 12개 지역의 340여 실내에서 측정한 라돈농도로부터 단순한 수학적 폐선량 평가모형을 이용하여 주민의 실효선량당량을 평가하였다. 수동적 시간적분형 CR-39 라돈컵으로 1990년 4월부터 10월까지 $3{\sim}4$개월 동안 측정 한 실내의 라돈농도는 지역별로 $33.82{\sim}61.42 Bq/m^3$(평균 : $48.90 Bq/m^3$)의 분포를 보였으며, 이로 인한 라돈자핵종의 평형등가라 돈농도$(EEC_{Rn})$는 라돈과 자핵종간의 평형인자의 값 0.4를 적용했을 때 $13.53{\sim}24.57Bq/m^3$(평균 : $19.55 Bq/m^3$)으로 예상되었다. 국제방사선방어위원회의 폐모형에 근거한 본 연구의 폐선량 평가모형에서 유도된 단위 평형등가라돈농도의 피폭당 실효선량당량환산 인자는 $1.07{\times}10^{-5}\;mSv/Bq\;h\;m^{-3}$으로 국제방사선방어위원회나 국제연합 방사선영향평가 과학위원회(UNSCEAR)에서 권고한 값과 잘 일치하였다. 동 선량환산인자와 CR-39 라돈 컵으로 측정 한 실내 의 평균 평형등가라돈농도를 년간 $0.75 m^3/h$의 호흡율로 호흡한 것으로 가정했을 때, 주민이 받는 년평균 폐선량당량 및 실효선량당량은 갹각 20.90 mSv 및 1.25 mSv인 것으로 평가되었다. 동 피폭선량은 국제연합(UNSCEAR)에서 1988년에 발표한 일반인의 년평균 자연방사선피폭 실효선량당량인 2.40mSv의 거의 50%에 상당하였다.