• 방사선산업학회지
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• 제17권2호
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• pp.161-172
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• 2023

Coal-fired power plants handle large quantities of coal, one of the most prominent NORM, and the coal ash produced after the coal is burned can be tens of times more radioactive than the coal. Workers in these industries may be exposed to internal exposure by inhalation of particles while handling NORM. This study evaluated the size, concentration, particle shape and density, and radioactivity concentrations of airborne suspended particles in the main processes of a coal-fired power plant. Finally, the internal radiation dose to workers from particle inhalation was evaluated. For this purpose, airborne particles were collected by size using a multi-stage particle collector to determine the size, shape, and concentration of particles. Samples of coal and coal ash were collected to measure the density and radioactivity of particles. The dose conversion factor and annual radionuclide inhalation amount were derived based on the characteristics of the particles. Finally, the internal radiation dose due to particle inhalation was evaluated. Overall, the internal radiation dose to workers in the main processes of coalfired power plants A and B ranged from 1.47×10^-5~1.12×10^-3 mSv y^-1. Due to the effect of dust generated during loading operations, the internal radiation dose of fly ash loading processes in both coal-fired power plants A and B was higher than that of other processes. In the case of workers in the coal storage yard at power plants A and B, the characteristic values such as particle size, airborne concentration, and working time were the same, but due to the difference in radioactivity concentration and density depending on the origin of the coal, the internal radiation dose by origin was different, and the highest was found when inhaling coal imported from Australia among the five origins. In addition, the main nuclide contributing the most to the internal radiation dose from the main processes in the coal-fired power plants was thorium due to differences in dose conversion factors. However, considering the external radiation dose of workers in coal-fired power plants presented in overseas research cases, the annual effective dose of workers in the main processes of power plants A and B does not exceed 1mSv y^-1, which is the dose limit for the general public notified by the Nuclear Safety Act. The results of this study can be utilized to identify the internal exposure levels of workers in domestic coal-fired power plants and will contribute to the establishment of a data base for a differential safety management system for NORM-handling industries in the future.

• 한국산업보건학회지
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• 제24권4호
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• pp.547-555
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• 2014

Objective: This study was conducted to investigate the association between subjective distress symptoms and argon welding among workers in Gyeongnam Province shipyard. Method: 31 argon and 29 non-argon welding workers were selected as study subjects in order to measure concentrations of personal dust, welding fumes and other hazardous materials such as ZnO, Pb, Cr, FeO, MnO, Cu, Ni, $TiO_2$, MgO, NO, $NO_2$, $O_3$, $O_2$, $CO_2$, CO and Ar. An interviewer-administered questionnaire survey was also performed on the same subjects. The items queried were as follows: age, height, weight, working duration, welding time, welding rod amounts used, drinking, smoking, and rate of subjective distress symptoms including headache and other symptoms such as fever, vomiting and nausea, metal fume fever, dizziness, tingling sensations, difficulty in breathing, memory loss, sleep disorders, emotional disturbance, hearing loss, hand tremors, visual impairment, neural abnormality, allergic reaction, runny nose and stuffiness, rhinitis, and suffocation. Statistical analysis was performed using SPSS software, version 18. Data are expressed as the mean ${\pm}SD$. An ${\chi}^2$-test and a normality test using a Shapiro wilk test were performed for the above variables. Logistic regression analysis was also conducted to identify the factors that affect the total score for subjective distress symptoms. Result: An association was shown between welding type (argon or non-argon welding) and the total score for subjective distress symptoms. Among the rate of complaining of subjective distress symptoms, vomiting and nausea, difficulty breathing, and allergic reactions were all significantly higher in the argon welding group. Only the concentration of dust and welding fumes was shown to be distributed normally after natural log transformation. According to logistic regression analysis, the correlations of working duration and welding type (argon or non-argon) between the total score of subjective distress symptoms were found to be statistically significant (p=0.041, p=0.049, respectively). Conclusion: Our results suggest that argon welding could cause subjective distress symptoms in shipyard workers.

• Asian-Australasian Journal of Animal Sciences
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• 제29권3호
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• pp.444-454
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• 2016

This study was designed to examine the characteristics of sawdust and cocopeat bedding materials, including physicochemical properties (Exp. I) and on-farm trial (Exp. II). In Exp. I, the proportion of particle size was in the order of sawdust>cocopeat India>cocopeat Vietnam (p<0.05), and cocopeat contained higher proportion of small particles ($250{\mu}m$+below $250{\mu}m$) than sawdust, causing a dust production problem. Bulk density was cocopeat India>cocopeat Vietnam>sawdust (p<0.05), thus cocopeat treatments showed 4.4 times higher bedding cost than sawdust. The water absorption rates were 702.0% in cocopeat India, 678.3% in cocopeat Vietnam, and 444.0% in sawdust, showing cocopeat had approximately 1.5 times higher water absorption rate than sawdust. Moisture evaporation rates after 12 h of air blowing (2.00 m/s) were higher (p<0.05) in cocopeat Vietnam (80.4%) than sawdust (71.2%) and cocopeat India (72.8%). In vitro ammonia emissions were higher (p<0.05) in sawdust ($2.71mg/m^2/h$) than cocopeat India ($1.59mg/m^2/h$) and Vietnam ($1.22mg/m^2/h$), and total ammonia emissions were higher (p<0.05) in sawdust ($37.02mg/m^2$) than cocopeat India ($22.51mg/m^2$) and Vietnam ($13.60mg/m^2$). In Exp. II, an on-farm trial was conducted with 48 Hanwoo cattle in 16 pens using the same bedding materials as in Exp. I, with fan (blowing 2.00 m/s) and no fan treatments, and feed bunk side (FB) and water supply side (WS) within a pen (4.5 m, $width{\times}9.0m$, length). Beddings were replaced with fresh bedding materials when moisture concentrations were over 65%. No interactions among treatments were detected for moisture concentration and increment rates, and ammonia concentrations, but a significant effect was observed (p<0.01) for each of the treatments. Both concentrations and increment rate of moisture were higher (p<0.01) in the beddings without fan than with fan. Moisture concentrations and increment rate within a pen were also higher (p<0.01) in FB than WS. Thus, the whole no-fan-FB and sawdust-fan-FB were replaced with fresh bedding material between 4 to 5 experimental weeks. The ammonia concentrations and pH of beddings were not significantly different among treatments. Therefore, using cocopeat bedding with a blowing fan can extend twice the bedding utilization period, and WS within a pen showed twice the bedding-life compared to FB. Despite the outstanding characteristics of cocopeat compared with sawdust, using cocopeat as an alternative for sawdust bedding is not recommended for cattle management, considering it has 4.4 times higher bedding cost and a dust production problem.

• 한국대기환경학회지
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• 제26권5호
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• pp.475-489
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• 2010

In order to verify the enhancement of ozone and carbon monoxide (CO) during springtime in East Asia, we investigated weather conditions and data from remote sensors, air quality models, and air quality monitors. These include the geopotential height archived from the final (FNL) meteorological field, the potential vorticity and the wind velocity simulated by the Meteorological Mesoscale Model 5 (MM5), the back trajectory estimated by the Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) model, the total column amount of ozone and the aerosol index retrieved from the Total Ozone Mapping Spectrometer (TOMS), the total column density of CO retrieved from the Measurement of Pollution in the Troposphere (MOPITT), and the concentration of ozone and CO simulated by the Model for Ozone and Related Chemical Tracers (MOZART). In particular, the total column density of CO, which mightoriginate from the combustion of fossil fuels and the burning of biomass in China, increased in East Asia during spring 2000. In addition, the enhancement of total column amounts of ozone and CO appeared to be associated with both the upper cut-off low near 500 hPa and the frontogenesis of a surface cyclone during a weak Asian dust event. At the same time, high concentrations of ozone and CO on the Earth's surface were shown at the Seoul air quality monitoring site, located at the surface frontogenesis in Korea. It was clear that the ozone was invaded by the downward stretched vortex anomalies, which included the ozone-rich airflow, during movement and development of the cut-off low, and then there was the catalytic photochemical reaction of ozone precursors on the Earth's surface during the day. In addition, air pollutants such as CO and aerosol were tracked along both the cyclone vortex and the strong westerly as shown at the back trajectory in Seoul and Busan, respectively. Consequently, the maxima of ozone and CO between the two areas showed up differently because of the time lag between those gases, including their catalytic photochemical reactions together with the invasion from the upper troposphere, as well as the path of their transport from China during the weak Asian dust event.

• 분석과학
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• 제24권5호
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• pp.395-400
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• 2011

본 연구는 [지정폐기물 중 신규유해물질 항목설정 및 시험방법 확립에 관한 연구]에 선정된 우선관리대상 미규제 유기물질 3종(PCDD/DFs, PAHs, PCBs)에 대해 효과적인 관리를 위하여 수행하였다. 국립환경과학원에서 제시된 함량시험법에 따라 분석하였으며, 폐유기용제, 폐페인트, 분진이 포함된 도료 및 제철 제강공정에서 발생하는 폐기물을 대상으로 함량을 결정하였다. GC/MSD를 이용한 PAHs 7종을 조사한 결과, 나프탈렌(N.D~1631.33 mg/kg)이 검출되었다. 폐유기용제와 폐페인트의 나프탈렌 결과 값은 해양배출처리기준을 초과하는 것으로 조사되었다. PCB 7종에 대해 함량 분석값은 전부 불검출로 나타났다. PCDD/DFs 분석결과, 바젤협약 기술지침서의 low POP 기준에 부합한 것으로 조사되었다. 10공정(빌렛, 불룸)에서 배출되는 분진 시료에서 PCDD/DFs의 함량 결과는 N.D~5.66 ng I-TEQ/g으로 조사되었다.

• 환경영향평가
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• 제27권5호
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• pp.431-446
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• 2018

본 연구에서는 충청남도 논산시 농촌지역의 대기 중 블랙카본, 이온, 금속원소 등을 포함한 $PM_{2.5}$의 화학적 특성을 규명하고 $PM_{2.5}$의 오염원을 정량적으로 평가하였다. 분석의 정도관리를 평가한 결과, 금속원소를 포함한 대부분의 미량성분의 분석값은 상대오차와 상대표준편차가 10% 미만이었다. 농촌지역의 $PM_{2.5}$의 평균 농도($20.1{\pm}10.1{\mu}g/m^3$)는 2018년에 강화된 연평균 기준을 초과하는 수준이었다. $PM_{2.5}$와 탄소 및 이온성분은 서로 유의한 상관성을 보였고, 미량성분의 농도는 $10^{-3}{\sim}10^4ng/m^3$ 범위인 것으로 나타났다. 양의 인자 분석법(PMF, Positive Matrix Factorization)을 이용하여 오염원을 평가한 결과, 농촌지역의 $PM_{2.5}$의 오염원은 secondary aerosol(34.4%), soil/road dust(20.1%), biomass burning(16.9%), incineration/fuel combustion(13.2%), vehicle exhaust(12.2%), sea-salt(3.17%) 이었다. 도시지역과 달리 농촌지역은 연소와 관련된 오염원이 중요하였고 따라서, 농촌지역의 관리 대상 오염원으로서 불법소각은 세심한 대책을 필요로 한다.

• 한국지구과학회지
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• 제23권6호
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• pp.514-525
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• 2002

본 연구는 서울시 북동지역의 군자동에 위치한 세종대학교를 중심으로 2001년 봄철 3월에서 4월까지 PM2.5와 PM10을 채취하여, 이들과 결합된 중금속 성분들에 대한 농도분포의 특성을 살펴보았다. 전체 관측기간 동안 산출된 PM2.5, PM10, 조대입자 영역(PM10-PM2.5)의 평균농도는 49.3${\pm}$29.2, 95.5${\pm}$46.1, 50.5${\pm}$35.0 ${\mu}g$/m$^3$으로 나타났다. 연구대상지역의 중금속 오염도를 살펴보기 위해 부화계수(enrichment factor: EF)를 비교한 결과, 미세 및 조대입자 모두에서 Zn, V, Cr, Pb, Cu, Ni, Co, Mo 등의 중금속 성분들의 EF값이 수십, 수백의 범위에 달할 정도로 오염의 수준이 심각하다는 것을 확인할 수 있었다. 미세/조대입자 영역간에 형성되는 농도비를 비교한 결과, Zn, Cr, Pb, Ni 등이 미세입자 영역에서 뚜렷하게 더 높은 농도를 보이는 것으로 확인되었다. 중금속 농도에 대해 보다 세부적인 분석을 실시한 결과, 중금속 성분들의 농도는 상당 수준 증가하는데, 이와 같은 증가는 황사의 영향을 상당 수준 받는 것으로 나타났다.

• 한국수자원학회논문집
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• 제37권11호
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• pp.959-967
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• 2004

충북 청주시에 위치한 충북대학교에서 강수에 따른 습성강하물 중의 TN, TP 및 COD의 농도와 오염부하를 조사하였다 강수사상에 대한 샘플은 1998년에서 2003년까지 채집되었다. 오염물질의 강수량가중평균 농도는 TN이 0.60mg/L, TP가 0.014mg/L, COD는 4.8mg/L이었는데, 이는 각각의 산술평균보다 26, 18, 14% 작게 나타났다. TN, TP 및 COD의 농도는 강수량이 증가함에 따라 감소하는 경향을 나타냈다. 모든 수질항목은 됨에 가장 많이 나타났는데, 이는 풍식 및 황사에 의한 먼지, 꽃가루 등 때문으로 생각된다. 습성강하물의 평균 연간부하는 TN 7.9kg/ha$\cdot$yr, TP 0.19kg/ha$\cdot$yr, COD 53.9ka/ha$\cdot$yr로 나타났는데, 이를 일본에서 보고된 각각의 연간부하와 비교하면 TN과 TP는 비슷했으나, COD는 약간 놀게 나타났다.

• 대한환경공학회지
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• 제29권6호
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• pp.728-733
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• 2007

본 연구에서는 개인용 컴퓨터(PC) 내부의 시료를 채취하여, 세균의 CFU와 곰팡이의 종류를 분석하였다. 시료는 대중 PC 이용 시설(PC방), 대학실험실 및 대학 전산실습실의 PC 51대에서 채취하였다. CFU(colony forming unit)법을 이용한 세균수의 경우, 컴퓨터 총 작동시간이 증가할수록 PC 내부의 세균수는 증가하는 것으로 확인되었으며$(r^2=0.90)$, PC 내부 부품 중에서는 CPU 냉각 팬에서 가장 높은 수치로 확인되었다(평균 605 $CFU/cm^2$). 곰팡이의 경우, 다수의 유해성을 지닌 곰팡이가 검출되었으며, 그 중 Aspergillus sp.와 Penicillium sp.가 가장 많은 비율로 존재함이 확인되었다. 또한 PC 내부에서 채취된 먼지에서는 mg 당 212 CFU의 세균이 발견되었다. 본 연구의 결과, PC 내부에는 여러 다양한 종류의 미생물이 존재한다는 것을 확인하였으며, 이 결과는 PC의 취급, 사용 및 정비 시 각종 미생물에 의한 감염의 가능성이 있다는 것을 나타내고 있다.

• 분석과학
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• 제15권4호
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• pp.381-387
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• 2002

미국산업위생학회 (American Industrial Hygiene Association, AIHA)와 미국환경보호청(US Environmental Protection Agency, EPA)에서 실시하는 납 분석 정도관리 프로그램에 가입하여 1999부터 2001년까지 매년 4회씩 공기, 페인트 칩, 토양 그리고 먼지 중 납을 분석하였다. 분석결과, 총 128개의 시료 중 126개의 결과가 적합 범위에 들어 전체적으로 'proficient' 인정을 받았다. 공기, 페인트 칩, 토양 그리고 먼지 중 납의 농도는 각각 $0.0089{\sim}0.3956mg/m^3$, 0.0500~8.9149%, 29.0~1697 mg/kg 그리고 $18.00{\sim}900.3{\mu}g/sample$ 이었다. 다양한 환경시료 중의 납은 각 매트릭스별로 적절한 전처리를 한 다음 불꽃 원자흡수분광광도법으로 불꽃 방법으로 분석하였다. 공기 중 납은 염산으로 추출하였고, 페인트 칩과 토양 시료는 마이크로웨이브와 핫플레이트에서 회화시키는 방법, 두 가지를 모두 이용하였다. 그리고 먼지 시료는 마이크로웨이브 회화법을 이용하였다. 각각의 전처리 방법에 따른 차이는 없었으며, 다양한 환경 시료 중의 납 분석방법으로 적당하였다.