• Safety and Health at Work
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• v.12 no.2
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• pp.174-183
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• 2021

Background: Toluene diisocyanate (TDI) is a highly reactive chemical that causes sensitization and has also been associated with increased lung cancer. A risk assessment was conducted based on occupational epidemiologic estimates for several health outcomes. Methods: Exposure and outcome details were extracted from published studies and a NIOSH Health Hazard Evaluation for new onset asthma, pulmonary function measurements, symptom prevalence, and mortality from lung cancer and respiratory disease. Summary exposure-response estimates were calculated taking into account relative precision and possible survivor selection effects. Attributable incidence of sensitization was estimated as were annual proportional losses of pulmonary function. Excess lifetime risks and benchmark doses were calculated. Results: Respiratory outcomes exhibited strong survivor bias. Asthma/sensitization exposure response decreased with increasing facility-average TDI air concentration as did TDI-associated pulmonary impairment. In a mortality cohort where mean employment duration was less than 1 year, survivor bias pre-empted estimation of lung cancer and respiratory disease exposure response. Conclusion: Controlling for survivor bias and assuming a linear dose-response with facility-average TDI concentrations, excess lifetime risks exceeding one per thousand occurred at about 2 ppt TDI for sensitization and respiratory impairment. Under alternate assumptions regarding stationary and cumulative effects, one per thousand excess risks were estimated at TDI concentrations of 10 - 30 ppt. The unexplained reported excess mortality from lung cancer and other lung diseases, if attributable to TDI or associated emissions, could represent a lifetime risk comparable to that of sensitization.

• Safety and Health at Work
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• v.7 no.3
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• pp.251-255
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• 2016

Background: Building demolition can lead to emission of dust into the environment. Exposure to silica dust may be considered as an important hazard in these sites. The objectives of this research were to determine the amount of workers' exposure to crystalline silica dust and assess the relative risk of silicosis and the excess lifetime risk of mortality from lung cancer in demolition workers. Methods: Four sites in the Tehran megacity region were selected. Silica dust was collected using the National Institute for Occupational Safety and Health method 7601 and determined spectrophotometrically. The Mannetje et al and Rice et al models were chosen to examine the rate of silicosis-related mortality and the excess lifetime risk of mortality from lung cancer, respectively. Results: The amount of demolition workers' exposure was in the range of $0.085-0.185mg/m^3$. The range of relative risk of silicosis related mortality was increased from 1 in the workers with the lowest exposure level to 22.64/1,000 in the employees with high exposure level. The range of the excess lifetime risk of mortality from lung cancer was in the range of 32-60/1,000 exposed workers. Conclusion: Geometric and arithmetic mean of exposure was higher than threshold limit value for silica dust in all demolition sites. The risk of silicosis mortality for many demolition workers was higher than 1/1,000 (unacceptable level of risk). Estimating the lifetime lung cancer mortality showed a higher risk of mortality from lung cancer in building demolition workers.

• Journal of Radiation Protection and Research
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• v.46 no.3
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• pp.83-97
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• 2021

Background: The lifetime risk of lung cancer incidence due to radiation for nonsmokers is overestimated because of the use of the average cancer baseline risk among a mixed population, including smokers. In recent years, the generalized multiplicative (GM)-excess relative risk (ERR) model has been developed in the life span study of atomic bomb survivors to consider the joint effect of radiation and smoking. Based on this background, this paper discusses the issues of radiation risk assessment considering smoking in two parts. Materials and Methods: In Part 1, we proposed a simple method of estimating the baseline risk for nonsmokers using current smoking data. We performed sensitivity analysis on baseline risk estimation to discuss the birth cohort effects. In Part 2, we applied the GM-ERR model for Japanese smokers to calculate lifetime attributable risk (LAR). We also performed a sensitivity analysis using other ERR models (e.g., simple additive (SA)-ERR model). Results and Discussion: In Part 1, the lifetime baseline risk from mixed population including smokers to nonsmokers decreased by 54% (44%-60%) for males and 24% (18%-29%) for females. In Part 2, comparison of LAR between SA- and GM-ERR models showed that if the radiation dose was ≤200 mGy or less, the difference between these ERR models was within the standard deviation of LAR due to the uncertainty of smoking information. Conclusion: The use of mixed population for baseline risk assessment overestimates the risk for lung cancer due to low-dose radiation exposure in Japanese males.

• Proceedings of the Korea Society of Environmental Toocicology Conference
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• 2004.11a
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• pp.41-42
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• 2004

• Journal of Environmental Science International
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• v.24 no.7
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• pp.927-937
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• 2015

This study was performed to identify and quantify the asbestos fibers released from two types of asbestos-cement slate roofs. One is a plant roof installed in 1987 which contained 15% chrysotile, and the other is a residential roof installed before 1983 which contained 12% chrysotile. The concentrations of asbestos fibers in air surrounding asbestos-cement slate roofs and in the falling water harvested from the same roofs on rainy days ranged from 0.0012 to 0.0018 f/mL and from 1,764 f/L to 10,584 f/L, respectively. The concentration of inorganic fibers in the soil around asbestos-cement slate roofs was from 217 to 348 f/g. With the above results, the excess lifetime cancer risk (ELCR) for the risk assessment of the asbestos fibers released from asbestos-cement slate based on US EPA IRIS (Integrated risk information system) model is within 5.5E-06 ~ 6.5E-06 levels which indicates that the levels do not exceed "the acceptable risk(1.0E-05)" recommended by WHO. The asbestos concentration in air, drained rainfall and soil around the plant slate roof was higher than that around residential slate roof, but the excess lifetime cancer risk (ELCR) from residential slate was higher than that from plant slate. This suggested that the enclose and encapsulation of residential roofs have priority in removal policy to minimize the exposure risk.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.325-336
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• 2019

The activity concentrations of $^{226}Ra$, $^{232}Th$, and $^{40}K$ from 102 building materials samples were determined using a high-purity germanium (HPGe) detector. The activity concentrations were evaluated for possible radiological hazards to the human health. The excess lifetime cancer risks (ELCR) were also estimated, and the average values were recorded as $0.42{\pm}0.24{\times}10^{-3}$, $3.22{\pm}1.83{\times}10^{-3}$, and $3.65{\pm}1.85{\times}10^{-3}$ for outdoor, indoor, and total ELCR respectively. The activity concentrations were further subjected to RESRAD-BUILD computer code to evaluate the long-term radiation exposure to a dweller. The indoor doses were assessed from zero up to 70 years. The simulation results were $92{\pm}59$, $689{\pm}566$, and $782{\pm}569{\mu}Sv\;y^{-1}$ for indoor external, internal, and total effective dose equivalent (TEDE) respectively. The results reported were all below the recommended maximum values. Therefore, the radiological hazards attributed to building materials under study are negligible.

• Journal of Environmental Health Sciences
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• v.45 no.3
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• pp.247-257
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• 2019

Objectives: The Korea Ministry of Environment regulates concentrations of hazardous air pollutants (HAPs) through Atmosphere Environmental Standards to protect public health from HAPs. However, simply determining the exceedance of HAP concentrations has several limitations and more comprehensive assessment is required. In addition, integrated risk assessment is needed considering exposure in all microenvironments, including outdoor as well as indoor environments. The purpose of this study was to assess the differences in risk by sub-population groups according to time-activity patterns and reported concentrations, as well as the lifetime risk for Koreans. Methods: In this study, we calculated time-weighted average exposure concentrations for benzene and $PM_{10}$ among preschool-age children, students, housewifes, workers, and the elderly using residential time and concentrations for indoor (house, school or workplace, other), outdoor, and transport by the meta-analysis method. The risk assessments were conducted by excess cancer risk and disease death risk using 1,000,000 Monte-Carlo simulations for probabilistic analysis. Results: Preschool-age children, students, housewifes, workers, and the elderly spent 91.9, 86.0, 79.8, 82.2, and 77.3% of their day in their house, workplace, or school, respectively. The more than 99% excess cancer risk for benzene exceed 1.0E-06 in all sub-populations and lifetime. The acute disease death risk for $PM_{10}$ for housewifes and workers for lifetime were 3.35E-04 and 3.18E-04, and chronic disease death risks were 2.84E-03 and 2.70E-03, respectively. Conclusions: The risk of benzene and $PM_{10}$ by sub-population group and for the lifetime of housewifes and workers were assessed. Benzene showed risky results for this study. All disease death risks of $PM_{10}$ were higher than 1.0E-04 and showed different risks by sub-population. This study can be used as a basis for lifetime exposure and risk assessment to benzene and $PM_{10}$.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.57-70
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• 1992

An excess risk of lung cancer mortality among Koreans, attributable to indoor $^{222}Rn$ daughters exposure, were quantitatively evaluated by applying a stochastic health risk projection model on the radiation exposure. The lung cancer rate in Korean males and females, based on the 1989 demographic data, were estimated to be $22.4/10^5-y\;and\;9.5/10^5-y$, respectively The lifetime baseline lung cancer risks, deduced from these rates, appeared to be 0.047 and 0.019 for males and females, respectively, and were lower than the corresponding 1984 values of 0.067 and 0.025 in the U.S.A. The excess risk coefficients, derived by modified relative risk projection model of the BEIR-IV Committee under the US National Academy of Science, per annual 1.0 WLM of exposure to indoor radon daughters were estimated to be 0.022/WLM for males, 0.009/WLM for females, and 0.017/WLM for both sexes. The resulting annual frequency of excess lung cancer mortality for the life expectancy in the Korean population appeared to be 230/10^6-WLM, which was an approximate median of $120{\sim}450/10^6-WLM$ reported so far in the world.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.1
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• pp.29-37
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• 1992

The risk of benzo(a)pyrene for cancer in the ambient air of Seoul was assessed by using the extrapolation methods. The average daily lifetime exposure of benzo(a)pyrene in the ambient air of Seoul was calculated at 6.97-24.30ng/$m^2$/day, which was based on the occurrence analysis of benzo(a)pyrene in the residential(Bull Kwang Dong) and traffic areas(Shin Chon) of Seoul. Using the dose scaling based on body surface area in comparisons of toxicity for extrapolation from animal to human and mathematical models from the high dose region, the low-dose risk was estimated. The response probabilities were estimated by the tolerance distribution models; Probit, Logit and Weibull model. They were consistent with the observed ones at experimental dose region. The unit risk estimates of these models were too low to be used. One-hit and multistage model to prove more conservative risk was selected. As a redult, the lifetime unit risk of benzo(a)pyrene for cancer and virtually safe dose were calculated; One-hit model provided the risk 2.8 $\times 10^{-7}$ and 3.4ng/$m^3$, respectively and multistage model provided 5.2 $\times 10^{-7}$ and 1.9ng/$m^3$ as the more conservatives. The lifetime excess risk estimates of benzo(a)pyrene for cancer were calculated at 0.37-1.30 persons/million persons by one-hit model and 0.69-2.41 persons/million persons by multistage model, which was considered in without virtual risk.

• Journal of Environmental Science International
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• v.22 no.12
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• pp.1579-1587
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• 2013

This study was performed to evaluate the asbestos exposure levels and to calculate excess lifetime cancer risk (ELCR) for the risk assessment of the asbestos fibers released from asbestos-cement slate roofing (ASR) building. Total number of ASR buildings was into 21,267 in Busan, and 82.03 percent of the buildings was residential houses, and 43.61 percent of the buildings was constructed in 1970s. For this study, ten buildings were selected randomly among the ASR buildings. The range of airborne asbestos concentration in the selected ten ASR buildings was from 0.0016 to 0.0067 f/mL, and the concentration around no-admitted ASR buildings was higher than that around admitted buildings. The ELCR based on US EPA IRIS (integrated risk information system) model is within 3.5E-05 ~ 1.5E-04 levels, and the ELCR of no-admitted ASR buildings was higher than 1.0E-04 (one person per million) level that is considered a more aggressive approach to mitigate risk. These results indicate that the cancer risk from ASR buildings is higher than other buildings, and systematic public management is required for control of no-admitted ASR buildings within near future.