• Title/Summary/Keyword: Probabilistic exposure assessment

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Quantitative microbial risk assessment of Campylobacter jejuni in jerky in Korea

  • Ha, Jimyeong;Lee, Heeyoung;Kim, Sejeong;Lee, Jeeyeon;Lee, Soomin;Choi, Yukyung;Oh, Hyemin;Yoon, Yohan
    • Asian-Australasian Journal of Animal Sciences
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    • v.32 no.2
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    • pp.274-281
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    • 2019
  • Objective: The objective of this study was to estimate the risk of Campylobacter jejuni (C. jejuni) infection from various jerky products in Korea. Methods: For the exposure assessment, the prevalence and predictive models of C. jejuni in the jerky and the temperature and time of the distribution and storage were investigated. In addition, the consumption amounts and frequencies of the products were also investigated. The data for C. jejuni for the prevalence, distribution temperature, distribution time, consumption amount, and consumption frequency were fitted with the @RISK fitting program to obtain appropriate probabilistic distributions. Subsequently, the dose-response models for Campylobacter were researched in the literature. Eventually, the distributions, predictive model, and dose-response model were used to make a simulation model with @RISK to estimate the risk of C. jejuni foodborne illness from the intake of jerky. Results: Among 275 jerky samples, there were no C. jejuni positive samples, and thus, the initial contamination level was statistically predicted with the RiskUniform distribution [RiskUniform (-2, 0.48)]. To describe the changes in the C. jejuni cell counts during distribution and storage, the developed predictive models with the Weibull model (primary model) and polynomial model (secondary model) were utilized. The appropriate probabilistic distribution was the BetaGeneral distribution, and it showed that the average jerky consumption was 51.83 g/d with a frequency of 0.61%. The developed simulation model from this data series and the dose-response model (Beta Poisson model) showed that the risk of C. jejuni foodborne illness per day per person from jerky consumption was $1.56{\times}10^{-12}$. Conclusion: This result suggests that the risk of C. jejuni in jerky could be considered low in Korea.

A Computerized Construction Cost Estimating Method based on the Actual Cost Data (실적 공사비에 의한 예정공사비 산정 전산화 방안)

  • Chun Jae-Youl;Cho Jae-ho;Park Sang-Jun
    • Korean Journal of Construction Engineering and Management
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    • v.2 no.2
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    • pp.90-97
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    • 2001
  • The paper considers non-deterministic methods of analysing the risk exposure in a cost estimate. The method(referred to as the 'Monte Carlo simulation' method) interprets cost data indirectly, to generate a probability distribution for total costs from the deficient elemental experience cost distribution. The Monte Carlo method is popular method for incorporating uncertainty relative to parameter values in risk assessment modelling. Non-deterministic methods, they are here presented as possibly effective foundation on which to risk management in cost estimating. The objectives of this research is to develop a computerized algorithms to forecast the probabilistic total construction cost and the elemental work cost at the planning stage.

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A Sensitivity Study on Nuclide Release from the Near-field of the Pyroprocessed Waste Repository System: Part 1. A Probabilistic Approach (파이로처리 폐기물 처분 시스템 근계 영역 내 핵종 유출 민감도: 제 1 부 확률론적 접근)

  • Lee, Youn-Myoung;Jeong, Jongtae
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.12 no.1
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    • pp.19-35
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    • 2014
  • A parametric sensitivity to the annual exposure dose rate to the farming exposure group has been probabilistically carried out for three principal elements associated with the nuclide transport behavior in the near-field of the pyroprocessed waste repository system. Credit time for both metal and ceramic containers, annual nuclide release rete, and the degree of loss of bentonite buffer around the container are selected as the elements and investigated for important nuclides. All the elements are shown to be sensitive to the results. Methodology studied through this study and the results are expected to make a good feedback to the repository design. As a follow-up study, separated in Part 2, the A-KRS will be deterministically assessed and then compared among each other with the normal, the worst, and the best case scenarios associated with their extreme values these elements could have.

Assessment of health risk associated with arsenic exposure from soil, groundwater, polished rice for setting target cleanup level nearby abandoned mines

  • Lee, Ji-Ho;Kim, Won-Il;Jeong, Eun-Jung;Yoo, Ji-Hyock;Kim, Ji-Young;Lee, Je-Bong;Im, Geon-Jae;Hong, Moo-Ki
    • Korean Journal of Soil Science and Fertilizer
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    • v.44 no.1
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    • pp.38-47
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    • 2011
  • This study focused on health risk assessment via multi-routes of As exposure to establish a target cleanup level (TCL) in abandoned mines. Soil, ground water, and rice samples were collected near ten abandoned mines in November 2009. The As contaminations measured in all samples were used for determining the probabilistic health risk by Monte-Carlo simulation techniques. The human exposure to As compound was attributed to ground water ingestion. Cancer risk probability (R) via ground water and rice intake exceeded the acceptable risk range of $10^{-6}{\sim}10^{-4}$ in all selected mines. In particular, the MB mine showed the higher R value than other mines. The non-carcinogenic effects, estimated by comparing the average As exposure with corresponding reference dose were determined by hazard quotient (HQ) values, which were less than 1.0 via ground water and rice intake in SD, NS, and MB mines. This implied that the non-carcinogenic toxic effects, due to this exposure pathway had a greater possibility to occur than those in other mines. Besides, hazard index (HI) values, representing overall toxic effects by summed the HQ values were also greater than 1.0 in SD, NS, JA, and IA mines. This revealed that non-carcinogenic toxic effects were generally occurred. The As contaminants in all selected mines exceeded the TCL values for target cancer risk ($10^{-6}$) through ground water ingestion and rice intake. However, the As level in soil was greater than TCL value for target cancer risk via inadvertent soil ingestion pathway, except for KK mine. In TCL values for target hazard quotient (THQ), the As contaminants in soil did not exceed such TCL value. On the contrary, the As levels in ground water and polished rice in SD, NS, IA, and MB mines were also beyond the TCL values via ground water and rice intake. This study concluded that the health risks through ground water and rice intake were greater than those though soil inadvertent ingestion and dermal contact. In addition, it suggests that the abandoned mines to exceed the risk-based TCL values are carefully necessary to monitor for soil remediation.

Monitoring of Neonicotinoid Pesticide Residues in Fruit Vegetable and Human Exposure Assessment (과채류 중 Neonicotinoid계 농약의 모니터링 및 인체노출평가)

  • Park, Byung-Jun;Son, Kyung-Ae;Paik, Min-Kyoung;Kim, Jin-Bae;Kwon, Hye-Young;Hong, Su-Myeong;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.104-109
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    • 2010
  • We investigated five neonicotinoid pesticide residues (acetamiprid, clothianidin, imidacloprid, thiacloprid, thiamethoxam) in fruit vegetables and estimated the exposure of neonicotinoid pesticide residue through fruit vegetable consumption using a deterministic approach. Two hundred forty samples of eight fruit vegetables cultivated in Korea were analyzed for their pesticide residue contents. Acetamiprid had the highest detection frequency and the highest residue level in pepper. However, all pesticide levels detected didn't exceed national MRLs. The results using a deterministic approach showed that for chronic and acute study of all neonicotinoid pesticide residues, the exposure was about 50 times lower than toxicological endpoint values. It is necessary to understand that the exposure assessment in this study using a probabilistic approach should be regarded as a important knowledge in the decision-making process.

Risk Assessment of Mercury through Food Intake for Korean Population (식품 중 수은 위해평가)

  • Choi, Hoon;Park, Sung-Kug;Kim, Mee-Hye
    • Korean Journal of Food Science and Technology
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    • v.44 no.1
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    • pp.106-113
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    • 2012
  • The present study was conducted to assess the dietary exposure to mercury and the associated risks for Koreans resulting from their food intake. The probabilistic approach in the Monte Carlo simulation was used to estimate dietary exposures. Based on several reports regarding heavy metals published by KFDA in the 2000s, 178 types of representative foods were selected and data were collected on the occurrence of mercury. The contents of mercury in foods ranged: agricultural products 0.1 (fruits)-45.4 ${\mu}g/kg$ (mushrooms), 3.7 ${\mu}g/kg$ (meat), and 9.3 (Echinodermata, chordata)-194.9 ${\mu}g/kg$ (fish). Others categories investigated were alcoholic beverages (0.7 ${\mu}g/kg$) and processed food (4.4 ${\mu}g/kg$). The mean and 95th percentile for exposure to dietary mercury were 4.29 and 12.48 ${\mu}g/day$, corresponding to 13.6% and 39.7% of PTWI (Provisional Tolerable Weekly Intake), respectively. Therefore, overall level of mercury exposure for Koreans through food intake is below levels recommended by JECFA, indicating the least possibility of risk, and is less than or similar to levels reported in other countries.

Acute and Chronic Exposure Assessment of Organophosphate Pesticides through the Consumption of Fruit Vegetables (과채류 섭취를 통한 유기인계 농약의 급성 및 만성노출평가)

  • Park, Byung-Jun;Gil, Keun-Hwan;Son, Kyeong-Ae;Im, Geon-Jae;Yoon, Hyunjoo;Park, Kyung-Hun;Kim, Doo-Ho;Ihm, Yangbin;Paik, Min-Kyoung
    • The Korean Journal of Pesticide Science
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    • v.18 no.2
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    • pp.95-103
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    • 2014
  • In this study, we monitored the residues of organophosphate pesticides (OP) in eight fruit vegetables grown in Korea, and assessed risk levels of acute and chronic exposure of OP through the consumption of fruit vegetables. Chlorpyrifos, EPN, methidathion and phosphamidon in eight fruit vegetables were detected in this study. The results of cumulative assessment of national estimated short term intake for acute exposure of OP were due to the following order; eggplant, tomato, squash and cucumber. Total theoretical maximum daily intake calculated at first step of chronic exposure assessment for registered OP in Korea was 76.14%, compared with acceptable daily intake ADI) based on chlorpyrifos. In addition, total national estimated maximum daily intake calculated at second step of chronic exposure assessment was 13.949%, compared with ADI. Third chronic assessment was conducted by probabilistic approach using OP residues detected in eight fruit vegetables and showed that total exposure risk was very low, corresponding to 0.0001% compared to ADI. Based on those finding, the risk of organophosphate pesticides in fruit vegetables was considered quantitatively negligible. In future, further investigation to expand the target should be followed to do more accurate and detailed risk assessment.

Assessment of Extreme Wind Risk for Window Systems in Apartment Buildings Based on Probabilistic Model (확률 모형 기반의 아파트 창호 시스템 강풍 위험도 평가)

  • Ham, Hee Jung;Yun, Woo-Seok;Choi, Seung Hun;Lee, Sungsu;Kim, Ho-Jeong
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.28 no.6
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    • pp.625-633
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    • 2015
  • In this study, a coupled probabilistic framework is developed to assess wind risk on apartment buildings by using the convolution of wind hazard and fragility functions. In this framework, typhoon induced extreme wind is estimated by applying the developed Monte Carlo simulation model to the climatological data of typhoons affecting Korean peninsular from 1951 to 2013. The Monte Carlo simulation technique is also used to assess wind fragility function for 4 different damage states by comparing the probability distributions of the window system's resistance performance and wind load. Wind hazard and fragility functions are modeled by the Weibull and lognormal probability distributions based on simulated wind speeds and failure probabilities. The modeled functions are convoluted to obtain the wind risk for the different damage levels. The developed probabilistic framework clearly shows that wind risk are influenced by various important characteristics of terrain and apartment building such as location of building, exposure category, topographic condition, roof angle, height of building, etc. The risk model presented in this paper can be used as tools to predict economic loss estimation and to establish wind risk mitigation plan for the existing building inventory.

A Probabilistic Assessment of Human Health Risk from Arsenic-Contaminated Rice Grown Near The Mining Areas of Korea

  • Paik, Min-Kyoung;Kim, Won-Il;Yoo, Ji-Hyock;Kim, Jin-Kyoung;Im, Geon-Jae;Hong, Moo-Ki
    • Journal of Food Hygiene and Safety
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    • v.25 no.2
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    • pp.143-147
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    • 2010
  • Chronic exposure to Arsenic (As) causes significant human health effects including various cancers. Total As concentrations from 300 polished rice samples cultivated near the mining areas in Korea were analyzed to estimate a probabilistic assessment of human health risk from As-contaminated rice. The mean of total As concentrations in rice was 0.09 mg/kg and lognormal distribution model was set for total As concentrations. Human health risk for As in rice was estimated using gender-specific rice consumption data and average daily dose (ADD). While cancer risk (CR) and hazard quotient (HQ) were calculated using oral cancer slope factor (OCSF) and Reference dose (RfD) suggested by the U.S. EPA. Mean of CR posed by total As was 2.16 (for male) and 1.83 (for female) per 10,000. The HQ for general population from rice cultivated near the mining areas in Korea was below 1 as the $50^{th}$ percentile of general population. However, less than 10% of general population consuming rice cultivated near the mining areas would exceed 1.0. This result is similar with those from each gender-specific group.

Application of Risk-Informed Inservice Inspection for Piping in Nuclear Power Plants (리스크 정보를 활용한 배관 가동중검사 적용)

  • Jin, Young Bok;Jin, Seuk Hong;Moon, Yong Sig
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.7 no.4
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    • pp.31-37
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    • 2011
  • Pressurized Water Reactor Owners Group(PWROG) proposed and applied a risk-informed inservice inspection(RI-ISI) program to alternate existing ASME Section XI periodic inspections. The RI-ISI programs enhance overall safety by focusing inspections of piping at high safety significant(HSS) and locations where failure mechanisms are likely to be present, and by improving the effectiveness on inspection of components because the examination methods are based on the postulated failure mode and the configuration of the piping structural element. The RI-ISI programs can reduce NDE, man-rem exposure, costs of engineering analysis, outage duration and chance of complicating plant operations etc. RI-ISI methods of piping inservice inspection were applied on 3 units(KSNP : Korea Standard Nuclear Power Plant) and are scheduled to apply on the other units. In this paper, we compared and showed the results of the 2 units and we concluded that the RI-ISI application could enhance and maintain plant safety and give unquantifiable benefits.