• Title/Summary/Keyword: Probabilistic exposure assessment

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Differences by Selection Method for Exposure Factor Input Distribution for Use in Probabilistic Consumer Exposure Assessment

  • Kang, Sohyun;Kim, Jinho;Lim, Miyoung;Lee, Kiyoung
    • Journal of Environmental Health Sciences
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    • v.48 no.5
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    • pp.266-271
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    • 2022
  • Background: The selection of distributions of input parameters is an important component in probabilistic exposure assessment. Goodness-of-fit (GOF) methods are used to determine the distribution of exposure factors. However, there are no clear guidelines for choosing an appropriate GOF method. Objectives: The outcomes of probabilistic consumer exposure assessment were compared by using five different GOF methods for the selection of input distributions: chi-squared test, Kolmogorov-Smirnov test (K-S), Anderson-Darling test (A-D), Akaike information criterion (AIC) and Bayesian information criterion (BIC). Methods: Individual exposures were estimated based on product usage factor combinations from 10,000 respondents. The distribution of individual exposure was considered as the true value of population exposures. Results: Among the five GOF methods, probabilistic exposure distributions using the A-D and K-S methods were similar to individual exposure estimations. Comparing the 95th percentiles of the probabilistic distributions and the individual estimations for 10 CPs, there were 0.73 to 1.92 times differences for the A-D method, and 0.73 to 1.60 times differences (excluding tire-shine spray) for the K-S method. Conclusions: There were significant differences in exposure assessment results among the selection of the GOF methods. Therefore, the GOF methods for probabilistic consumer exposure assessment should be carefully selected.

Comparison of Deterministic and Probabilistic Approaches through Cases of Exposure Assessment of Child Products (어린이용품 노출평가 연구에서의 결정론적 및 확률론적 방법론 사용실태 분석 및 고찰)

  • Jang, Bo Youn;Jeong, Da-In;Lee, Hunjoo
    • Journal of Environmental Health Sciences
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    • v.43 no.3
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    • pp.223-232
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    • 2017
  • Objectives: In response to increased interest in the safety of children's products, a risk management system is being prepared through exposure assessment of hazardous chemicals. To estimate exposure levels, risk assessors are using deterministic and probabilistic approaches to statistical methodology and a commercialized Monte Carlo simulation based on tools (MCTool) to efficiently support calculation of the probability density functions. This study was conducted to analyze and discuss the usage patterns and problems associated with the results of these two approaches and MCTools used in the case of probabilistic approaches by reviewing research reports related to exposure assessment for children's products. Methods: We collected six research reports on exposure and risk assessment of children's products and summarized the deterministic results and corresponding underlying distributions for exposure dose and concentration results estimated through deterministic and probabilistic approaches. We focused on mechanisms and differences in the MCTools used for decision making with probabilistic distributions to validate the simulation adequacy in detail. Results: The estimation results of exposure dose and concentration from the deterministic approaches were 0.19-3.98 times higher than the results from the probabilistic approach. For the probabilistic approach, the use of lognormal, Student's T, and Weibull distributions had the highest frequency as underlying distributions of the input parameters. However, we could not examine the reasons for the selection of each distribution because of the absence of test-statistics. In addition, there were some cases estimating the discrete probability distribution model as the underlying distribution for continuous variables, such as weight. To find the cause of abnormal simulations, we applied two MCTools used for all reports and described the improper usage routes of MCTools. Conclusions: For transparent and realistic exposure assessment, it is necessary to 1) establish standardized guidelines for the proper use of the two statistical approaches, including notes by MCTool and 2) consider the development of a new software tool with proper configurations and features specialized for risk assessment. Such guidelines and software will make exposure assessment more user-friendly, consistent, and rapid in the future.

Application of Probabilistic Health Risk Analysis in Life Cycle Assessment -Part I : Life Cycle Assessment for Environmental Load of Chemical Products using Probabilistic Health Risk Analysis : A Case Study (전과정평가에 있어 확률론적 건강영향분석기법 적용 -Part II : 화학제품의 환경부하 전과정평가에 있어 건강영향분석 모의사례연구)

  • Park, Jae-Sung;Choi, Kwang-Soo
    • Journal of Environmental Impact Assessment
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    • v.9 no.3
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    • pp.203-214
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    • 2000
  • Health risk assessment is applied to streamlining LCA(Life Cycle Assessment) using Monte carlo simulation for probabilistic/stochastic exposure and risk distribution analysis caused by data variability and uncertainty. A case study was carried out to find benefits of this application. BTC(Benzene, Trichloroethylene, Carbon tetrachloride mixture alias) personal exposure cases were assumed as production worker(in workplace), manager(in office) and business man(outdoor). These cases were different from occupational retention time and exposure concentration for BTC consumption pattern. The result of cancer risk in these 3 scenario cases were estimated as $1.72E-4{\pm}1.2E+0$(production worker; case A), $9.62E-5{\pm}1.44E-5$(manger; case B), $6.90E-5{\pm}1.16E+0$(business man; case C), respectively. Portions of over acceptable risk 1.00E-4(assumed standard) were 99.85%, 38.89% and 0.61%, respectively. Estimated BTC risk was log-normal pattern, but some of distributions did not have any formal patterns. Except first impact factor(BTC emission quantity), sensitivity analysis showed that main effective factor was retention time in their occupational exposure sites. This case study is a good example to cover that LCA with probabilistic risk analysis tool can supply various significant information such as statistical distribution including personal/environmental exposure level, daily time activity pattern and individual susceptibility. Further research is needed for investigating real data of these input variables and personal exposure concentration and application of this study methodology.

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A Method for Operational Safety Assessment of a Deep Geological Repository for Spent Fuels

  • Jeong, Jongtae;Cho, Dong-Keun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.18 no.spc
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    • pp.63-74
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    • 2020
  • The operational safety assessment is an important part of a safety case for the deep geological repository of spent fuels. It consists of different stages such as the identification of initiating events, event tree analysis, fault tree analysis, and evaluation of exposure doses to the public and radiation workers. This study develops a probabilistic safety assessment method for the operational safety assessment and establishes an assessment framework. For the event and fault tree analyses, we propose the advanced information management system for probabilistic safety assessment (AIMS-PSA Manager). In addition, we propose the Radiological Safety Analysis Computer (RSAC) program to evaluate exposure doses to the public and radiation workers. Furthermore, we check the applicability of the assessment framework with respect to drop accidents of a spent fuel assembly arising out of crane failure, at the surface facility of the KRS+ (KAERI Reference disposal System for SNFs). The methods and tools established through this study can be used for the development of a safety case for the KRS+ system as well as for the design modification and the operational safety assessment of the KRS+ system.

Probabilistic Approach on Dietary Exposure Assessment of Neonicotinoid Pesticide Residues in Fruit Vegetables (과채류 섭취를 통한 Neonicotinoid계 농약의 노출평가에 대한 확률적 접근)

  • Paik, Min-Kyoung;Park, Byung-Jun;Son, Kyung-Ae;Kim, Jin-Bae;Hong, Su-Myeong;Kim, Won-Il;Im, Geon-Jae;Hong, Moo-Ki
    • The Korean Journal of Pesticide Science
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    • v.14 no.2
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    • pp.110-115
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    • 2010
  • The aim of this study is to investigate the exposure assessment of Korean consumers to five neonicotinoid pesticides in fruit vegetables cultivated in Korea, using a probabilistic approach. We used five neonicotionid pesticides residues(acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) data in fruit vegetables reported by Rural Development Administration for the 2009 monitoring programme. Total exposure of five neonicotinoid pesticides for Korean consumer ranged from 0.087 to 0.236 ${\mu}g$/kg/day at the $95^{th}$ percentile. The $95^{th}$ percentile values of total exposure of five neonicotinoid pesticides by probabilistic approach were lower than those by deterministic approach, although mean values of total exposure by probabilistic approach were similar with those of total exposure by deterministic approach. Total exposure to acetamiprid residue may be mainly due to the exposure to acetamiprid through the consumption of strawberry. Also, acetamiprid residues in strawberry were considered as much more contributory factor to total exposure of acetamiprid than consumption data of strawberry. This contributory properties of acetamiprid were similar with those of all other neonicotinoid pesticides, excluding thiacloprid.

A Probabilistic Safety Assessment of a Pyro-processed Waste Repository (A-KRS 처분 시스템 확률론적 안전성 평가)

  • Lee, Youn-Myoung;Jeong, Jongtae
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.10 no.4
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    • pp.263-272
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    • 2012
  • A GoldSim template program for a safety assessment of a hybrid-typed repository system, called A-KRS, in which two kinds of pyro-processed radioactive wastes, low-level metal wastes and ceramic high-level wastes that arise from the pyro-processing of PWR nuclear spent fuels are disposed of, has been developed. This program is ready both for a deterministic and probabilistic total system performance assessment which is able to evaluate nuclide release from the repository and farther transport into the geosphere and biosphere under various normal, disruptive natural and manmade events, and scenarios. The A-KRS has been probabilistically assessed with 9 selected input parameters, each of which has its own statistical distribution for a normal release and transport scenario associated with nuclide release and transport in and around the repository. Probabilistic dose exposure rates to the farming exposure group have been evaluated. A sensitivity of 9 selected parameters to the result has also been investigated to see which parameter is more sensitive and important to the exposure rates.

Human Health Risk Assessment of Benzene from Industrial Complexes of Chungcheong and Jeonla Province (충청·전라지역 산업단지 주변지역에서의 벤젠 인체 위해성 평가)

  • Jang, Yong-Chul;Lee, Sungwoo;Shin, YongSeung;Kim, Heekap;Lee, Jonghyun
    • Journal of Environmental Impact Assessment
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    • v.20 no.4
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    • pp.497-507
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    • 2011
  • This research studied human health risk assessment of benzene from industrial complexes of Chungcheong Province (Seosan industrial complex) and Jeonla Province (Iksan industrial complex and Yeosoo industrial complex). The residents near the industrial complexes areas can be often exposed to volatile organic compounds (e.g., benzene, toluene, xylenes) through a number of exposure pathways, including inhalation of the organic pollutant via various environmental matrices (air, water and soil), contaminated water, and soil intake. Benzene is well known to be a common carcinogenic and toxic compound that is produced from industrial and oil refinery complexes. In this study, a number of samples from water, air, and soil were taken from the residential settings and public school zones located near the industrial complex sites. Based on the carcinogenic risk assessment, the risk estimates were slightly above $10{\times}10^{-6}$ at all three industrial sites. According to deterministic risk assessment, inhalation was the most important route. The distribution of benzene in the environment would be dependent on vapor pressure, and the physical property influencing the extent of the potential risks. Non-carcinogenic risk assessment of benzene shows that the values of Hazard Index(HI) were much lower than 1.0 at all industrial complexes. Therefore, benzene was not a cause of concern in terms of non-carcinogenic risk posed to the residents near the sites. When compared to probabilistic risk assessment, the CTE(central tendency exposure) cancer risk values of deterministic risk assessment were close to the mean values predicted by the probabilistic risk assessment. The RME(reasonable maximum exposure) values fell within the range of 95% to 99.9% estimated by the probabilistic risk assessment. Since the values of carcinogenic risk assessment were higher than $10{\times}10^{-6}$, further detailed monitoring and refined risk assessment for benzene may be warranted to estimate more reliable and potential inhalation risks to receptors near the industrial complexes.

Comparative Study of Probabilistic Ecological Risk Assessment (PERA) used in Developed Countries and Proposed PERA approach for Korean Water Environment (확률생태위해성평가(PERA) 선진국 사례분석 및 국내수계에 적합한 PERA 기법 제안)

  • An, Youn-Joo;Nam, Sun-Hwa;Lee, Woo-Mi
    • Journal of Korean Society on Water Environment
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    • v.25 no.4
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    • pp.494-501
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    • 2009
  • Probabilistic Ecological risk assessment (PERA) is extensive approach to qualify and quantify risk on the multi species based on species sensitivity distribution (SSD). As a while, deterministic ecological risk assessment (DERA) considers the comparison of predicted no-effect concentration (PNEC) and predicted exposure concentration (PEC). DERA is used to determine if there is potential risk or no risk, and it doesn't consider the nature variability and the species sensitivity. But PERA can be more realistic and reasonable approach to estimate likelihood or risk. In this study, we compared PERA used in developed countries, and proposed PERA applicable for the Korean water environment. Taxonomic groups were classified as "class" level including Actinopterygill, Branchiopoda, Chlorophyceae, Maxillapoda, Insects, Bivalvia, Gastropoda, Secernentea, Polychaeta, Monocotyldoneae, and Chanophyceae in this study. Statistical extrapolation method (SEM), statistical extrapolation method $_{acutechronicratio}$ ($SEM_{ACR}$) and assessment factor method (AFM) were used to calculate the ecological protective concentration based on qualitative and quantitative levels of taxonomic toxicity data. This study would be useful to establish the PERA for the protection of aquatic ecosystem in Korea.

Human Risk Assessment of Perchloroethylene Considering Multi-media Exposure (다매체 노출을 고려한 Perchloroethylene의 인체위해성평가연구)

  • Seo, Jungkwan;Kim, Taksoo;Jo, Areum;Kim, Pilje;Choi, Kyunghee
    • Journal of Environmental Health Sciences
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    • v.40 no.5
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    • pp.397-406
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    • 2014
  • Objectives: Perchloroethylene (PCE) is a volatile chemical widely used as a solvent in the dry-cleaning and textile processing industries. It was evaluated as Group 2 "probably carcinogenic to humans" by the Integrated Risk Information System (IRIS) of the United State Environmental Protection Agency (U.S. EPA) in 2012. In order to provide a scientific basis for establishing risk management measures for chemicals on the national priority substances list, aggregate risk assessment was conducted for PCE, included in the top-10 substances. Methods: We conducted the investigation and monitoring of PCE exposure (e.g., exposure scenario, detection levels, and exposure factors, etc.) and assessed its multi-media (e.g., outdoor air, indoor air, and ground water) exposure risk with a deterministic and probabilistic approach. Results: In human risk assessment (HRA), the level of human exposure was higher in the younger age group. The exposure level through inhalation at home was the highest among the exposure routes. Outdoor air or uptake of drinking water represented less than 1% of total contributions to PCE exposure. These findings suggested that the level of risk was negligible since the Hazard Index (HI) induced by HRA was below one among all age groups, with a maximum HI value of 0.17 when reasonable maximum exposure was applied. Conclusion: In conclusion, it was suggested that despite low exposure risk, further studies are needed considering main sources, including occupational exposure.

Proposed Approach of Korean Ecological Risk Assessment for the Derivation of Soil Quality Criteria (토양준거치 도출을 위한 국내형 생태위해성평가기법 제안)

  • An, Youn-Joo;Lee, Woo-Mi;Nam, Sun-Hwa;Jeong, Seung-Woo
    • Journal of Soil and Groundwater Environment
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    • v.15 no.3
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    • pp.7-14
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    • 2010
  • Ecological Risk Assessment (ERA) supports a decision-making process such as establishment of environmental quality criteria. Soil quality criteria (SQC) are essential to protect soil organisms from the exposure to various soil contaminants. In this study, ERA methodologies of advanced countries for soil pollution were extensively compared to propose the ERA approach suitable for soil ecosystem in Korea. The soil ERAs in European Chemical Bureau(ECB), The Netherlands, and Canada can be classified as deterministic ecological risk assessment (DERA), and probabilistic ecological risk assessment (PERA) based on species sensitivity distribution (SSD). We propose three ERA methods according to abundance and reliability of soil ecotoxicity data. The method considered land use such as residential/agricultural, and industrial/commercial uses. The taxonomic groups of soil organism were classified as 'Class' level including different trophic levels (Magnoliopsida or Liliopsida, Clitellata, and Insecta or Secernentea). This study can be used to estimate the soil quality criteria to protect soil biota.