• Environmental Analysis Health and Toxicology
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• 제10권1_2호
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• pp.21-35
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• 1995

Risk assessment processes, which include processes for the estimation of human cancer potency using animal bioassay data and calculation of human exposure, entail uncertainties. In the exposure assessment process, exposure scenarios with various assumptions could affect the exposure amount and excess cancer risk. We compared risk estimates among various exposure scenarios of vinyl chloride, trichloroethylene and tetrachloroethylene in tap water. The contaminant concentrations were analyzed from tap water samples in Seoul from 1993 to 1994. The oral and inhalation cancer potencies of the contaminants were estimated using multistage, Weibull, lognormal, and Mantel-Bryan model in TOX-RISK computer software. In the first case, human excess cancer risk was estimated by the US EPA method used to set the MCL(maximum contaminant level). In the second and third case, the risk was estimated for multi-route exposure with and without adopting Monte-Carlo simulation, respectively. In the second case, exposure input parameters and cancer potencies used probability distributions, and in the third case, those values used point estimates(mean, and maximum or 95% upper-bound value). As a result, while the excess cancer risk estimated by US EPA method considering only direct ingestion tended to be underestimated, the risk which was estimated by considering multi-route exposure without Monte-Carlo simulation and then using the maximum or 95% upper-bound value as input parameters tended to be overestimated. In risk assessment for volatile organic compounds, considering multi-route exposure with adopting Monte-Carlo analysis seems to provide the most reasonable estimations.

• 한국환경보건학회지
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• 제44권5호
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• pp.460-467
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• 2018

Objectives: The objectives of this study are to estimate the inhalation exposure level of benzene for workers using Tier 1 exposure models ECETOC TRA (European Center for Ecotoxicology and Toxicology of Chemicals Target Risk Assessment) and Stoffenmanager, and to investigate their reliability for exposure assessment in K-REACH. Methods: Two exposure scenarios, 'manufacture of benzene' and 'use as solvents,' were developed for assessment of workers' exposure to benzene. The Process Category (PROC) for ECETOC TRA was collected from the European Chemical Agency (ECHA) registration dossier, and the Activity for Stoffenmanager was converted from PROC using translation of exposure models (TREXMO). The information related to exposure, such as working duration, Respiratory Protective Equipment (RPE), Local Exhaust Ventilation (LEV), and Risk Management Measure (RMM) were classified into high, medium, and low exposure conditions. The risk was determined by the ratio of the estimated exposure and occupational exposure limits of benzene. Results: Under high exposure conditions, the worker exposure level calculated from all PROCs and Activities exceeded the risk level, with the exception of PROC 1 and Activity 1. In the medium exposure condition, PROC 8a, 8b, and 9 and Activity 3, 7, and 8 all exceeded the risk, whereas in the low condition, all PROCs and Activities were determined to be safe. As a result, action corresponding with the low exposure condition is required to reduce the risk of exposure among workers in workplaces where benzene is manufactured or used as a solvent. In addition, the predicted exposure levels derived from the exposure models were lower than measured levels. The exposure levels estimated from Stoffenmanager were more conservative than those from ECETOC TRA. Conclusions: This study demonstrates the feasibility of exposure models for exposure assessment through the example of occupational inhalation exposure assessment for benzene. For more active utilization of exposure models in K-REACH, the exact application of collected information and accurate interpretation of obtained results are necessary.

• 한국산업보건학회지
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• 제5권1호
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• pp.16-39
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• 1995

From July 8 to September 2 1994, asbestos exposure level among asbestos textile workers was surveyed. Six plants out of plants in Korea were selected for this study. In addition to the exposure level, the relationship between the level of exposure and some factors affecting exposure were studied. Also, using historical data of asbestos concentrations in asbestos textile plants plus current data, trend of asbestos exposure level could be introduced. Historical exposure level was estimated on the basis of these data. The main results of this study are follows. 1. Average concentration of all six plants surveyed was 1.54 f/cc, and range of those concentrations was 0.03 - 11.58 f/cc. The minimum average concentration was 0.32 f/cc and the maximum was 8.04 f/cc which is four times higher than the Korean standard. A wide difference of exposure level among the workers of different plants was observed. In three plants, the half of all the plants surveyed, their average concentrations exceeded the Korean standard, and those in all the plants exceeded the ACGIH TLV. 2. Among total 56 samples, 22 samples(39%) were in excess of the Korean standard, and 53 samples(95%) were above the ACGIH TLV. Among 32 personal samples, 15 samples(47%) exceeded the Korean standard, and 30 samples(94%) exceeded the ACGIH TLV. Among 24 area samples excluding a few samples collected in office area, seven samples exceeded the Korean standard, and 23 samples( 96%) exceeded the ACGIH TLV. 3. Distributions of concentrations were observed by processes. In weaving, the highest, average concentration was 4.29 f/cc, and range was 2.61 - 11.58 f/cc. In spinning, average concentration was 2.22 f/cc, and range was 0.41 - 8.93 f/cc. In carding, average concentration was 1.98 f/cc, and range was 0.23 - 10.93 f/cc, In twisting, average concentration was 1.65 f/cc, and range was 0.21 - 9.83 f/cc. In mixing, the lowest, average concentration was 0.48 f/cc, and range was 0.22 - 1.20 f/cc. 4. All the samples from basic processes of asbestos textile plants were above the ACGIH TLV. Nineteen samples(45%) out of all these 42 samples exceeded Korean standard. Fourteen samples(58%) of total 24 personal samples, and five samples(28%) of total 18 area samples exceeded the Korean standard. Considering processes, all the samples in weaving process exceeded the Korean standard and 50 did 54% of those in spinning, 40% in carding, and 27% in twisting. 5. Trend of decreasing asbestos concentrations in asbestos textile plants was observed by time. 6. Asbestos concentrations in asbestos textile plant in 1975 were estimated to be 11.0 - 92.4 f/cc.

• 대한환경공학회지
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• 제27권10호
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• pp.1090-1098
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• 2005

벤조일 퍼록사이드는 수서생물에 대해 매우 높은 독성을 나타냄에도 불구하고 환경 중 잔류 농도 및 노출영향에 대해 연구가 이루어지지 않아 OECD에서 추천하고 있는 대표적인 다매체 환경거동 모델인 EQC 모델을 이용하여 본 물질에 대한 환경중의 농도를 예측하고 위해성평가 및 화학물질의 관리를 수행하기 위한 기초자료로 활용코자 하였다. 평형, 정상상태에서 100,000 kg의 벤조일 퍼록사이드가 환경내로 유입된 상태를 나타내는 Level I과 평형, 정상상태 이류와 분해현상이 있고 일정한 속도 1,000 kg/h로 유입되었을 경우를 나타내는 Level II에서 벤조일 퍼록사이드는 주로 토양(68.3%)과 물(28.7%)로 배출되는 것으로 예측되었다. 비평형, 정상상태, 이류와 분해현상이 있고 다매체 이동을 하는 시스템에서 벤조일 퍼록사이드가 대기, 물, 토양, 침전물의 각각의 4개 매체에 연속적으로 1,000 kg/h로 유입될 경우인 Level III에서는 주로 토양(99.9%)으로 배출되었고 전체 잔류시간은 3.4년으로 예측되어 벤조일 퍼록사이드가 환경 중에 잔류성이 있는 물질로 평가되었다.

• 한국건설관리학회논문집
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• 제5권2호
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• pp.136-143
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• 2004

본 논문은 초기 건설공사의 리스크 관리방법론을 제시한 것으로서, 리스크식별 및 분석을 중심으로 연구를 진행하였다. 리스크식별은 초기 건설공사를 $공통공사\cdot토공사\cdot지정$ 및 기초공사로 구분하여 리스크를 규명하고 작업분류체계에 기반하여 리스크분류체계를 제안하였다. 리스크분석은 리스크분류체계를 바탕으로 퍼지추론을 이용하여 리스크인자의 위험도를 정량화하고 퍼지척도를 이용하여 리스크인자의 중요도를 산정하였으며, 이를 통합하여 상위 리스크인자의 종합위험도를 구하기 위해 퍼지적분을 이용하였다. 리스크인자의 관리 우선순위는 종합위험도로부터 결정할 수 있다. 본 연구에서 제시한 리스크 관리 방법론의 타당성을 확인하기 위하여 사례적용을 실시하였으며, 그 결과 제시한 방법론이 현장 및 공사의 특성을 반영하여 리스크인자의 관리 우선순위를 결정하는데 충분히 활용할 수 있음을 확인할 수 있었다.

• 한국환경보건학회지
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• 제27권1호
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• pp.20-26
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• 2001

personal nitrogen dioxide(NO$_2$) exposures for 31 professional drivers were measured using passive sampler and time activity diary in Asan and Chunan area, and were estimated using time-weighted average model. Mean concentrations of driver’s indoor and outdoor were 24.7$\pm$10.7 ppb and 23.3$\pm$8.3 ppb, respectively with indoor/outdoor of 1.1. Mean personal NO$_2$ exposure was 30.3$\pm$9.7 ppb. Personal NO$_2$ exposures were strongly correlated with indoor car NO$_2$ levels ($R^2$=0.80) rather than residential indoor NO$_2$ level ($R^2$=0.55). and outdoor NO$_2$ level ($R^2$=0.50). The driver’s NO$_2$ exposure using LP-gas with 24.4$\pm$8.0 ppb were statistically different from those using diesel with 36.3$\pm$14.1 ppb(p<0.01). The effect of driver’s smoking for personal NO$_2$ exposure was not found. It was considered that the main NO$_2$in driver is transportation. Since drivers mostly spent their times in indoor and inside car, time-weighted average model could be used to estimated personal NO$_2$ exposure using time activity diary, Though we did not measure all microenvironments, the estimated personal NO$_2$ exposures with 26.9$\pm$10.2 ppb were statistically correlated with measured personal NO $_2$ exposures30.3$\pm$9.7 ppb ($R^2$=0.89). The mean and standard deviation of personal NO$_2$ exposure using Mote-Carlo simulation were 26.6$\pm$7.2 ppb.

• Environmental Analysis Health and Toxicology
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• 제19권1호
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• pp.49-58
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• 2004

It is important to select a risk based priority area for environmental policy formation and decision-making. We estimated the health risks and associated damage costs from exposure to fine particles and assigned priority areas for twenty -five districts in Seoul. In order to estimate the theoretical mortality incidence of the health risk, baseline risks were estimated from mortality rates in two low level areas of fine particles, Seocho Gu and Cheju city To estimate the damage cost from the risk estimates, we investigated and estimated the willingness to pay (WTP) for specific risk reduction. We assumed two different locations as the reference area, Cheju city as Scenario I and Seocho gu as Scenario II. From the results, the five districts, Kwangjin, Chungnang, Kangbuk, Nowon, and Kangnam, ranked high in the categories of both health risk and economic risk. Damage costs were over twenty billion won in each of these districts. As there are uncertainties in these results, the parameter values such as PM$_{2.5}$ level, dose -response slope factor, baseline risk, exposure population and WTP should be continuously validated and refined.d.

• 한국환경과학회지
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• 제10권3호
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• pp.195-200
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• 2001

The personal exposures of nitrogen dioxide(NO$_2$), microenvironmental levels and daily time activity patterns on Seoul subway station workers were measured from February 10 to March 12, 1999. Personal NO$_2$exposure for 24 hours were 29.40$\pm$9.75 ppb. NO$_2$level of occupational environment were 27.87$\pm$7.15 ppb in office, 33.60$\pm$8.64 ppb in platform and 50.13$\pm$13.04 ppb in outdoor. Personal exposure time of subway station workers was constituted as survey results with $7.94\pm$3.00 hours in office, $2.82\pm$1.63 hours in platform and 1 hours in outdoor. With above results, personal $NO_2$exposure distributions on subway station workers in Seoul were estimated with Monte Carlo simulation which uses statistical probabilistic theory on various exposure scenario testing. Some of distributions which did not have any formal patterns were assumed as custom distribution type. Estimated personal occupational $NO_2$exposure using time weighted average (TWA) model was 31.$29\pm$5.57 ppb, which were under Annual Ambient Standard (50ppb) of Korea. Though arithmetic means of measured personal $NO_2$exposure was lower than that of occupational $NO_2$exposure estimated by TWA model, considering probability distribution type simulated, probability distribution of measured personal $NO_2$exposures for 24 hours was over ambient standard with 3.23%, which was higher than those of occupational exposure(0.02%). Further research is needed for reducing these 24 hour $NO_2$personal excess exposures besides occupational exposure on subway station workers in Seoul.

• 환경위생공학
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• 제13권3호
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• pp.66-71
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• 1998

This study was investigated to evaluate worker exposures to organic solvents by type of print industry. Results were as follows; 1. Workers were exposed to mixture of toluene, isopropyl alcohol(IPA), methyl ethyl ketone(MEK), n-hexane, ethylacetate(EA), acetone. The components of high exposure solvents were toluene, IPA and MEK. 2. Considering additive effects of the compounds, exposure indices(Em) were calculated. The Mean of exposure indices were 1.79 for Gravere, 0.41 for Screen and 0.14 for Opset workplace. The workers of Gravere workplace were estimated to overexpose for solvents. 3. The highest overexposed solvent was toluene for a single component. The rate of overexposed level for toluene was 7.41% for some print workplace and for mixed solvent was 1.85％. 4. Local exhaust systems were inappropriate and respiratory protective devices were not supplied to the workers. 5. Sound level was over 90dB(A) in Opset print workplace and some measures should be performed to get down the sound level.

• 한국환경보건학회지
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• 제43권3호
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• pp.185-193
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• 2017

Objectives: An on-site study was conducted in order to quantify indoor exposure levels and the emission rate of particulate matter for domestic poultry buildings. Materials and methods: Three types of poultry building (caged layer house, broiler house, and layer house with manure belt) as classified by mode of manure treatment and ventilation were investigated in this study. Nine sites per each poultry building were selected and visited for measuring exposure levels and emission rate of particulate matter. Total dust and respirable dust among the particulate matter were analyzed based on the weight method. Emission rates were estimated by dividing emission amount, which was calculated through multiplying indoor concentration ($mg/m^3$), by the ventilation rate ($m^3/h$), into indoor area ($m^2$) and number of poultry reared in the poultry building. Results: Mean exposure levels for total dust and respirable dust in the poultry buildings were $3.91({\pm}1.99)mg/m^3$ and $1.99({\pm}0.89)mg/m^3$, respectively. The emission rates of particulate matter in the poultry buildings were estimated as $4.75({\pm}1.22)mg\;head^{-1}h^{-1}$ and $64.39({\pm}24.95)g\;m^{-2}h^{-1}$ for total dust and $0.58({\pm}0.23)mg\;head^{-1}h^{-1}$ and $7.52({\pm}2.51)mg\;m^{-2}h^{-1}$ for respirable dust, respectively. The distribution patterns for total dust and respirable dust were similar regardless of poultry building type. Among poultry buildings, broiler house showed the highest exposure level and emission rate of total dust and respirable dust, followed by layer house with manure belt and caged layer house. Conclusions: The finding that the broiler house showed the highest exposure level and emission rate of particulate matter can be attributed to sawdust utilized as bedding material, which can be dispersed into the air by movements of the chickens. Thus, a work environmental management solution for optimally reducing dust concentrations is necessary for broiler houses.