• 대한예방의학회:학술대회논문집
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• 대한예방의학회 1994년도 교수 연수회(환경)
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• pp.450-468
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• 1994

Scientists have long used conventional toxicological methods to establish 'safe levels of exposure' for chemicals presumed to have threshold health effects or doses below which significant effects are unlikely to occur. These same methods cannot be used to establish safe levels of exposure for non-threshold pollutants. such as carcinogens. Therefore. Federal regulatory agencies in the United States are using risk assessment methods to provide information for public health policy decisions concerning increases in risk associated with increases in exposure to carcinogenic and other non-threshold pollutants. Acceptable exposure/risk levels are decided by policymakers who consider descriptions and estimates of risks together with social and economic benefits from the uses of the chemical. 1bis paper focuses on the development of quantitative risk assessment approaches by Federal regulatory agencies in the United States, and identifies the mathematical models currently being used for risk extrapolation. including their inherent uncertainties. The uncertainties and limitations of these methods have led some scientists to question the utility of quantitative risk extrapolation. The experience of the; U.S. Environmental Protection Agency (EPA). as summarized in this paper. can provide a realistic basis for evaluating the pros and cons. Finally. shortcomings in current risk assessment methods and their use in policy decisions are explored. and areas for possible improvement. given current scientific knowledge. are identified.

• Environmental Analysis Health and Toxicology
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• 제17권4호
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• pp.273-284
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• 2002

At present, the health risks associated with the natural radionuclides of ground water have become a concern as potential social problems. However, there are no regulatory actions or control strategies for such risks. Therefore, we have investigated and discussed the risks and associated management strategies for radionuclides in other countries. US EPA has proposed MCL (300 pCi/L) and AMCL (4,000 pCi/L) for radon, and 30 ppb for uranium, 15 pCi/L for gross-alpha and 5 pCi/L for radium as final MCLs. Also, Canada, WHO and European countries have their inherent management levels. Finally, we suggested several criteria for setting guidelines in our countries including exposure related criteria such as geological distribution, occurrence, exposure probability distribution, exposure population and multimedia exposure assessment, acceptable risk, and cost -benefit analysis. The national-scale exposure and risk assessment, and economic analysis should be conducted for producing and aggregating the representative information on these criteria.

• Toxicological Research
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• 제28권3호
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• pp.173-178
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• 2012

This study investigated the human health risks of trichloroethylene from Industrial Complex A. The excessive carcinogenic risks for central tendency exposure were $1.40{\times}10^{-5}$ for male and female residents in the vicinity of Industrial Complex A. The excessive cancers risk for reasonable maximum exposure were $2.88{\times}10^{-5}$ and $1.97{\times}10^{-5}$ for males and females, respectively. These values indicate that there are potential cancer risks for exposure to these concentrations. The hazard index for central tendency exposure to trichloroethylene was 1.71 for male and female residents. The hazard indexes for reasonable maximum exposure were 3.27 and 2.41 for males and females, respectively. These values were over one, which is equivalent to the threshold value. This result showed that adverse cancer and non-cancer health effects may occur and that some risk management of trichloroethylene from Industrial Complex A was needed.

• 한국산업보건학회지
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• 제28권3호
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• pp.319-329
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• 2018

Objectives: The object of this paper is to analyze difference of general and occupational characters, risk exposure and ill health symptom depending on the special type of employment. Methods: 50,007 participants from Fourth Korean Working Condition Survey conducted in 2014 was analyzed. Cross-tabulation analysis was conducted for deriving difference in general and occupational characters, mulitvariate logistic regression analysis was conducted after controlling general and occupational characters for deriving difference in risk exposure and ill health symptom depending on the special type of employment. Results: In the special type of employment, female, ages of 50, education levels of high school, monthly income of 2,000-3,000 thousand won, job types of sales person, enterprises of less than 100 workers, working duration of 2-10 years and long working hours worker's proportion was higher than general employment. Physical(OR: 0.84, 95% CI: 0.76-0.94) and ergonomic (OR: 0.48, 95% CI: 0.42-0.55) risk exposure was lower, psychological(OR: 1.77, 95% CI: 1.54-2.04) risk exposure was higher than general employment, and there was no significant difference between the special type of employment and general employment in chemical/biological risk exposure(OR: 1.06, 95% CI: 0.94-1.20) and ill health symptom(OR: 0.98, 95% CI: 0.89-1.09). Conclusions: This article offers the analysing difference between the special type of employment and general employment using huge size cross sectional data represent Korean employees.

• 한국환경보건학회지
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• 제45권1호
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• pp.9-17
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• 2019

Objectives: This study examined the safety of tattoo ink by analyzing the phenol contents in tattoo inks and its risk assessment of selected phenol. Methods: A sample of 30 tattoo inks was purchased, the phenol contents were analyzed, and a risk assessment on dermal exposure from tattooing was carried out. Hazard identification was collected from toxicity data on systemic effects caused by dermal exposure to phenol, and the most sensitive toxicity value was adopted. Exposure assessment ($Exposure_{phenol}$) was calculated by applying phenol contents and standard exposure factors, while dose-response assessment was based on the collected toxicity data and skin absorption rate of phenol, assessment factors (AFs) for derived no-effect level ($DNEL_{demal}$). In addition, the risk characterization was calculated by comparing the risk characterization ratio (RCR) with $Exposure_{phenol}$ and $DNEL_{dermal}$ Results: The phenol concentration in the 30 products was from 1.4 to $649.1{\mu}g/g$. The toxicity value for systemic effects of phenol was adopted at 107 mg/kg. $Exposure_{phenol}$ in tattooing was from 0.000087 to 0.040442 mg/kg. $DNEL_{dermal}$ was calculated at 0.0072 mg/kg (=toxicity value 107 mg/kg ${\div}$ AFs 650 ${\times}$ skin absorption rate 4.4%). Thirteen out of 30 products showed an RCR between 1.02 and 5.62. The RCR of all red inks was above 1. Conclusions: Phenol was detected in all of the 30 tattoo inks, and the RCR of 13 products above 1 indicates a high level of risk concern, making it necessary to prepare safety management standards for phenol in tattoo inks.

• Journal of Preventive Medicine and Public Health
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• 제43권6호
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• pp.543-548
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• 2010

Objectives: The objective of this study was to calculate sample size and power in an ongoing cohort, Korea radiation effect and epidemiology cohort (KREEC). Method: Sample size calculation was performed using PASS 2002 based on Cox regression and Poisson regression models. Person-year was calculated by using data from '1993-1997 Total cancer incidence by sex and age, Seoul' and Korean statistical informative service. Results: With the assumption of relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, sample size calculation was 405 events based on a Cox regression model. When the relative risk was assumed to be 1.5 then number of events was 170. Based on a Poisson regression model, relative risk=1.3, exposure:non-exposure=1:2 and power=0.8 rendered 385 events. Relative risk of 1.5 resulted in a total of 157 events. We calculated person-years (PY) with event numbers and cancer incidence rate in the nonexposure group. Based on a Cox regression model, with relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, 136 245PY was needed to secure the power. In a Poisson regression model, with relative risk=1.3, exposure:non-exposure=1:2 and power=0.8, person-year needed was 129517PY. A total of 1939 cases were identified in KREEC until December 2007. Conclusions: A retrospective power calculation in an ongoing study might be biased by the data. Prospective power calculation should be carried out based on various assumptions prior to the study.

• 한국농공학회논문집
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• 제50권4호
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• pp.17-24
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• 2008

Exposure risk assessment of pesticide molinate using the RICEWQ model in a rice paddy plot was performed to observe the effects of various water and pesticide management scenarios. Several scenarios were developed to represent the specific water and pesticide management practices of rice cultivation in Korea. The results of the scenario analysis using the RICEWQ model simulation from the previous studies were analysed. The molinate risk for aquatic organisms is evaluated by the ratio of the predicted environmental concentration(PEC) and the predicted no-effect concentration(PNEC). The results showed that the no-effect periods for aquatic organisms for the deep, shallow and very shallow irrigation conditions were 33.3, 28.9 and 25.6 DATs for the lable rate application and 36.4, 33.7 and 30.8 DATs for the double lable rate application, respectively. The higher application rate showed greater exposure risk to the aquatic organisms. Based on this study, the withholding period of molinate practiced in Korea, that is 3 to 4 DATs, must be much longer. The results of this study can be used for the non-point source pollution control and environmental policy making regarding pesticides.

• Environmental Analysis Health and Toxicology
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• 제12권3_4호
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• pp.31-41
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• 1997

Public concerns about hazardous health effect from the exposure to organic by-products of the chlorination have been increased. There are numerous studies reporting that chlorination of drinking water produces numerous chlorinated organic by-products including THMs, HAAs, HANs. Some of these products are known to be animal carcinogens. The purpose of this study was to estimate health risk of DBPs by chlorinated drinking water ingestion in Seoul based on methodologies that have been developed for conducting risk assessment of complex-chemical-mixture. The drinking water sample was collected seperately at six water treatment plant in Seoul at March, April, 1996. In tap water of households in Seoul, DBPs were measured wilfh the mean value of 36.6 $\mu$g/L. 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. The reference dose of haloacetonitriles was estimated to be 0.0023 mg/kg/day by applying dibromoacetonitrile NOAEL and uncertainty factor to the mean concentration. 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 Trihalomethanes, considering multi-route exposure with adopting Monte-Carlo analysis seems to provide the most reasonable estimations.

• 한국산업보건학회지
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• 제22권3호
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• pp.191-199
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• 2012

Objectives: The study aim was to evaluate the application of a chemical exposure assessment tool for the Korean workplace. The Ministry of Employment and Labor in Korea (KMOEL) introduced the need for workplace risk assessments in 2011, requiring the Korean chemical industry to consider both domestic and international chemical regulation policies (e.g., estimations of exposure scenarios). Exposure scenarios are required in the European Union as part of material safety data sheets (MSDS) under the Registration, Evaluation, Authorization, and Restriction of Chemicals (REACH) system. Methods: Although many programs for the estimation of exposure have been developed worldwide, to date there is no standard for the Korean workplace. To develop programs suitable for the Korean workplace, we examined the applicability of the European Center for Ecotoxicology and Toxicology of Chemicals target risk assessment (ECETOC TRA), which is recommended by the European Chemical Agency (ECHA). Results: To investigate the applicability of the ECETOC TRA to Korean industry, this study simulated 15 industrial processes. The predicted respiratory exposures for four processes using origin input parameters were underestimated compared to the measured respiratory exposure. Using calibrated input parameters, results for two processes were underestimated compared to the measured respiratory exposure. This result suggests that the use of calibrated input parameters reduces the differences between predicted and measured respiratory exposure. Conclusions: we developed applicable exposure estimating method by modifying the ECETOC TRA program; one suggested the development of exposure estimating program that explains Korea domestic workplace exposure scenario.This study will support the introduction of exposure scenario in MSDS system and protect health of worker from hazardous chemical.

• 대한치과교정학회지
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• 제51권3호
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• pp.189-198
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• 2021

Objective: To estimate the projected cancer risk attributable to diagnostic cone-beam computed tomography (CBCT) performed under different exposure settings for orthodontic purposes in children and adults. Methods: We collected a list of CBCT machines and their specifications from 38 orthodontists. Organ doses were estimated using median and maximum exposure settings of 105 kVp/156.8 mAs and 130 kVp/200 mAs, respectively. The projected cancer risk attributable to CBCT procedures performed 1-3 times within 2 years was calculated for children (aged 5 and 10 years) and adult (aged 20, 30, and 40 years) male and female patients. Results: For maximum exposure settings, the mean lifetime fractional ratio (LFR) was 14.28% for children and 0.91% for adults; this indicated that the risk to children was 16 times the risk to adults. For median exposure settings, the mean LFR was 5.25% and 0.58% for children and adults, respectively. The risk of cancer decreased with increasing age. For both median and maximum exposure settings, females showed a higher risk of cancer than did males in all age groups. Cancer risk increased with an increase in the frequency of CBCT procedures within a given period. Conclusions: The projected dental CBCT-associated cancer risk spans over a wide range depending on the machine parameters and image acquisition settings. Children and female patients are at a higher risk of developing cancer associated with diagnostic CBCT. Therefore, the use of diagnostic CBCT should be justified, and protective measures should be taken to minimize the harmful biological effects of radiation.