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Sample records for exposure assessment model

  1. Advanced REACH tool: A Bayesian model for occupational exposure assessment

    NARCIS (Netherlands)

    McNally, K.; Warren, N.; Fransman, W.; Entink, R.K.; Schinkel, J.; Van Tongeren, M.; Cherrie, J.W.; Kromhout, H.; Schneider, T.; Tielemans, E.

    2014-01-01

    This paper describes a Bayesian model for the assessment of inhalation exposures in an occupational setting; the methodology underpins a freely available web-based application for exposure assessment, the Advanced REACH Tool (ART). The ART is a higher tier exposure tool that combines disparate

  2. Task-based dermal exposure models for regulatory risk assessment.

    Science.gov (United States)

    Warren, Nicholas D; Marquart, Hans; Christopher, Yvette; Laitinen, Juha; VAN Hemmen, Joop J

    2006-07-01

    The regulatory risk assessment of chemicals requires the estimation of occupational dermal exposure. Until recently, the models used were either based on limited data or were specific to a particular class of chemical or application. The EU project RISKOFDERM has gathered a considerable number of new measurements of dermal exposure together with detailed contextual information. This article describes the development of a set of generic task-based models capable of predicting potential dermal exposure to both solids and liquids in a wide range of situations. To facilitate modelling of the wide variety of dermal exposure situations six separate models were made for groupings of exposure scenarios called Dermal Exposure Operation units (DEO units). These task-based groupings cluster exposure scenarios with regard to the expected routes of dermal exposure and the expected influence of exposure determinants. Within these groupings linear mixed effect models were used to estimate the influence of various exposure determinants and to estimate components of variance. The models predict median potential dermal exposure rates for the hands and the rest of the body from the values of relevant exposure determinants. These rates are expressed as mg or microl product per minute. Using these median potential dermal exposure rates and an accompanying geometric standard deviation allows a range of exposure percentiles to be calculated.

  3. Determinants of Dermal Exposure Relevant for Exposure Modelling in Regulatory Risk Assessment

    NARCIS (Netherlands)

    Marquart, J.; Brouwer, D.H.; Gijsbers, J.H.J.; Links, I.H.M.; Warren, N.; Hemmen, J.J. van

    2003-01-01

    Risk assessment of chemicals requires assessment of the exposure levels of workers. In the absence of adequate specific measured data, models are often used to estimate exposure levels. For dermal exposure only a few models exist, which are not validated externally. In the scope of a large European

  4. Task-based dermal exposure models for regulatory risk assessment

    NARCIS (Netherlands)

    Warren, N.D.; Marquart, H.; Christopher, Y.; Laitinen, J.; Hemmen, J.J. van

    2006-01-01

    The regulatory risk assessment of chemicals requires the estimation of occupational dermal exposure. Until recently, the models used were either based on limited data or were specific to a particular class of chemical or application. The EU project RISKOFDERM has gathered a considerable number of

  5. Modeling Exposure to Persistent Chemicals in Hazard and Risk Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Cowan-Ellsberry, Christina E.; McLachlan, Michael S.; Arnot, Jon A.; MacLeod, Matthew; McKone, Thomas E.; Wania, Frank

    2008-11-01

    Fate and exposure modeling has not thus far been explicitly used in the risk profile documents prepared to evaluate significant adverse effect of candidate chemicals for either the Stockholm Convention or the Convention on Long-Range Transboundary Air Pollution. However, we believe models have considerable potential to improve the risk profiles. Fate and exposure models are already used routinely in other similar regulatory applications to inform decisions, and they have been instrumental in building our current understanding of the fate of POP and PBT chemicals in the environment. The goal of this paper is to motivate the use of fate and exposure models in preparing risk profiles in the POP assessment procedure by providing strategies for incorporating and using models. The ways that fate and exposure models can be used to improve and inform the development of risk profiles include: (1) Benchmarking the ratio of exposure and emissions of candidate chemicals to the same ratio for known POPs, thereby opening the possibility of combining this ratio with the relative emissions and relative toxicity to arrive at a measure of relative risk. (2) Directly estimating the exposure of the environment, biota and humans to provide information to complement measurements, or where measurements are not available or are limited. (3) To identify the key processes and chemical and/or environmental parameters that determine the exposure; thereby allowing the effective prioritization of research or measurements to improve the risk profile. (4) Predicting future time trends including how quickly exposure levels in remote areas would respond to reductions in emissions. Currently there is no standardized consensus model for use in the risk profile context. Therefore, to choose the appropriate model the risk profile developer must evaluate how appropriate an existing model is for a specific setting and whether the assumptions and input data are relevant in the context of the application

  6. Modeling exposure to persistent chemicals in hazard and risk assessment.

    Science.gov (United States)

    Cowan-Ellsberry, Christina E; McLachlan, Michael S; Arnot, Jon A; Macleod, Matthew; McKone, Thomas E; Wania, Frank

    2009-10-01

    Fate and exposure modeling has not, thus far, been explicitly used in the risk profile documents prepared for evaluating the significant adverse effect of candidate chemicals for either the Stockholm Convention or the Convention on Long-Range Transboundary Air Pollution. However, we believe models have considerable potential to improve the risk profiles. Fate and exposure models are already used routinely in other similar regulatory applications to inform decisions, and they have been instrumental in building our current understanding of the fate of persistent organic pollutants (POP) and persistent, bioaccumulative, and toxic (PBT) chemicals in the environment. The goal of this publication is to motivate the use of fate and exposure models in preparing risk profiles in the POP assessment procedure by providing strategies for incorporating and using models. The ways that fate and exposure models can be used to improve and inform the development of risk profiles include 1) benchmarking the ratio of exposure and emissions of candidate chemicals to the same ratio for known POPs, thereby opening the possibility of combining this ratio with the relative emissions and relative toxicity to arrive at a measure of relative risk; 2) directly estimating the exposure of the environment, biota, and humans to provide information to complement measurements or where measurements are not available or are limited; 3) to identify the key processes and chemical or environmental parameters that determine the exposure, thereby allowing the effective prioritization of research or measurements to improve the risk profile; and 4) forecasting future time trends, including how quickly exposure levels in remote areas would respond to reductions in emissions. Currently there is no standardized consensus model for use in the risk profile context. Therefore, to choose the appropriate model the risk profile developer must evaluate how appropriate an existing model is for a specific setting and

  7. Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

    International Nuclear Information System (INIS)

    Caudeville, Julien; Bonnard, Roseline; Boudet, Céline; Denys, Sébastien; Govaert, Gérard; Cicolella, André

    2012-01-01

    Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: -identify and manage geographic areas where hotspot exposures are a potential risk to human health; and -reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km 2 regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. -- Highlights: ► We present a multimedia exposure model for mapping environmental disparities. ► We perform a risk assessment on a region of France at a fine scale for three metals. ► We examine exposure determinants and detect vulnerable population. ► The largest

  8. Determinants of dermal exposure relevant for exposure modelling in regulatory risk assessment.

    Science.gov (United States)

    Marquart, J; Brouwer, D H; Gijsbers, J H J; Links, I H M; Warren, N; van Hemmen, J J

    2003-11-01

    Risk assessment of chemicals requires assessment of the exposure levels of workers. In the absence of adequate specific measured data, models are often used to estimate exposure levels. For dermal exposure only a few models exist, which are not validated externally. In the scope of a large European research programme, an analysis of potential dermal exposure determinants was made based on the available studies and models and on the expert judgement of the authors of this publication. Only a few potential determinants appear to have been studied in depth. Several studies have included clusters of determinants into vaguely defined parameters, such as 'task' or 'cleaning and maintenance of clothing'. Other studies include several highly correlated parameters, such as 'amount of product handled', 'duration of task' and 'area treated', and separation of these parameters to study their individual influence is not possible. However, based on the available information, a number of determinants could clearly be defined as proven or highly plausible determinants of dermal exposure in one or more exposure situation. This information was combined with expert judgement on the scientific plausibility of the influence of parameters that have not been extensively studied and on the possibilities to gather relevant information during a risk assessment process. The result of this effort is a list of determinants relevant for dermal exposure models in the scope of regulatory risk assessment. The determinants have been divided into the major categories 'substance and product characteristics', 'task done by the worker', 'process technique and equipment', 'exposure control measures', 'worker characteristics and habits' and 'area and situation'. To account for the complex nature of the dermal exposure processes, a further subdivision was made into the three major processes 'direct contact', 'surface contact' and 'deposition'.

  9. Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale.

    Science.gov (United States)

    Caudeville, Julien; Bonnard, Roseline; Boudet, Céline; Denys, Sébastien; Govaert, Gérard; Cicolella, André

    2012-08-15

    Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: - identify and manage geographic areas where hotspot exposures are a potential risk to human health; and - reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km(2) regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Development of a spatial stochastic multimedia exposure model to assess population exposure at a regional scale

    Energy Technology Data Exchange (ETDEWEB)

    Caudeville, Julien, E-mail: Julien.CAUDEVILLE@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Joint research unit UMR 6599, Heudiasyc (Heuristic and Diagnoses of Complex Systems), University of Technology of Compiegne and CNRS, Rue du Dr Schweitzer, 60200 Compiegne (France); Bonnard, Roseline, E-mail: Roseline.BONNARD@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Boudet, Celine, E-mail: Celine.BOUDET@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Denys, Sebastien, E-mail: Sebastien.DENYS@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Govaert, Gerard, E-mail: gerard.govaert@utc.fr [Joint research unit UMR 6599, Heudiasyc (Heuristic and Diagnoses of Complex Systems), University of Technology of Compiegne and CNRS, Rue du Dr Schweitzer, 60200 Compiegne (France); Cicolella, Andre, E-mail: Andre.CICOLELLA@ineris.fr [INERIS (French National Institute for Industrial Environment and Risks), Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France)

    2012-08-15

    Analyzing the relationship between the environment and health has become a major focus of public health efforts in France, as evidenced by the national action plans for health and the environment. These plans have identified the following two priorities: -identify and manage geographic areas where hotspot exposures are a potential risk to human health; and -reduce exposure inequalities. The aim of this study is to develop a spatial stochastic multimedia exposure model for detecting vulnerable populations and analyzing exposure determinants at a fine resolution and regional scale. A multimedia exposure model was developed by INERIS to assess the transfer of substances from the environment to humans through inhalation and ingestion pathways. The RESPIR project adds a spatial dimension by linking GIS (Geographic Information System) to the model. Tools are developed using modeling, spatial analysis and geostatistic methods to build and discretize interesting variables and indicators from different supports and resolutions on a 1-km{sup 2} regular grid. We applied this model to the risk assessment of exposure to metals (cadmium, lead and nickel) using data from a region in France (Nord-Pas-de-Calais). The considered exposure pathways include the atmospheric contaminant inhalation and ingestion of soil, vegetation, meat, egg, milk, fish and drinking water. Exposure scenarios are defined for different reference groups (age, dietary properties, and the fraction of food produced locally). The two largest risks correspond to an ancient industrial site (Metaleurop) and the Lille agglomeration. In these areas, cadmium, vegetation ingestion and soil contamination are the principal determinants of the computed risk. -- Highlights: Black-Right-Pointing-Pointer We present a multimedia exposure model for mapping environmental disparities. Black-Right-Pointing-Pointer We perform a risk assessment on a region of France at a fine scale for three metals. Black-Right-Pointing-Pointer We

  11. Stoffenmanager exposure model: company-specific exposure assessments using a Bayesian methodology.

    NARCIS (Netherlands)

    Ven, P. van de; Fransman, W.; Schinkel, J.; Rubingh, C.; Warren, N.; Tielemans, E.

    2010-01-01

    The web-based tool "Stoffenmanager" was initially developed to assist small- and medium-sized enterprises in the Netherlands to make qualitative risk assessments and to provide advice on control at the workplace. The tool uses a mechanistic model to arrive at a "Stoffenmanager score" for exposure.

  12. Harmonization of future needs for dermal exposure assessment and modeling : a workshop report

    NARCIS (Netherlands)

    Marquart, H.; Maidment, S.; Mcclaflin, J.L.; Fehrenbacher, M.C.

    2001-01-01

    Dermal exposure assessment and modeling is still in early phases of development. This article presents the results of a workshop organized to harmonize the future needs in this field. Methods for dermal exposure assessment either assess the mass of contaminant that is transferred to the skin, or the

  13. An Exploratory Study: Assessment of Modeled Dioxin Exposure in Ceramic Art Studios (Final Report, 2008)

    Science.gov (United States)

    EPA announced the availability of the final report, An Exploratory Study: Assessment of Modeled Dioxin Exposure in Ceramic Art Studios. This report investigates the potential dioxin exposure to artists/hobbyists who use ball clay to make pottery and related products. Derm...

  14. A review of air exchange rate models for air pollution exposure assessments.

    Science.gov (United States)

    Breen, Michael S; Schultz, Bradley D; Sohn, Michael D; Long, Thomas; Langstaff, John; Williams, Ronald; Isaacs, Kristin; Meng, Qing Yu; Stallings, Casson; Smith, Luther

    2014-11-01

    A critical aspect of air pollution exposure assessments is estimation of the air exchange rate (AER) for various buildings where people spend their time. The AER, which is the rate of exchange of indoor air with outdoor air, is an important determinant for entry of outdoor air pollutants and for removal of indoor-emitted air pollutants. This paper presents an overview and critical analysis of the scientific literature on empirical and physically based AER models for residential and commercial buildings; the models highlighted here are feasible for exposure assessments as extensive inputs are not required. Models are included for the three types of airflows that can occur across building envelopes: leakage, natural ventilation, and mechanical ventilation. Guidance is provided to select the preferable AER model based on available data, desired temporal resolution, types of airflows, and types of buildings included in the exposure assessment. For exposure assessments with some limited building leakage or AER measurements, strategies are described to reduce AER model uncertainty. This review will facilitate the selection of AER models in support of air pollution exposure assessments.

  15. Indoor aerosol modeling for assessment of exposure and respiratory tract deposited dose

    Science.gov (United States)

    Hussein, Tareq; Wierzbicka, Aneta; Löndahl, Jakob; Lazaridis, Mihalis; Hänninen, Otto

    2015-04-01

    Air pollution is one of the major environmental problems that influence people's health. Exposure to harmful particulate matter (PM) occurs both outdoors and indoors, but while people spend most of their time indoors, the indoor exposures tend to dominate. Moreover, higher PM concentrations due to indoor sources and tightness of indoor environments may substantially add to the outdoor originating exposures. Empirical and real-time assessment of human exposure is often impossible; therefore, indoor aerosol modeling (IAM) can be used as a superior method in exposure and health effects studies. This paper presents a simple approach in combining available aerosol-based modeling techniques to evaluate the real-time exposure and respiratory tract deposited dose based on particle size. Our simple approach consists of outdoor aerosol data base, IAM simulations, time-activity pattern data-base, physical-chemical properties of inhaled aerosols, and semi-empirical deposition fraction of aerosols in the respiratory tract. These modeling techniques allow the characterization of regional deposited dose in any metric: particle mass, particle number, and surface area. The first part of this presentation reviews recent advances in simple mass-balance based modeling methods that are needed in analyzing the health relevance of indoor exposures. The second part illustrates the use of IAM in the calculations of exposure and deposited dose. Contrary to previous methods, the approach presented is a real-time approach and it goes beyond the exposure assessment to provide the required information for the health risk assessment, which is the respiratory tract deposited dose. This simplified approach is foreseen to support epidemiological studies focusing on exposures originating from both indoor and outdoor sources.

  16. Predictive models for the assessment of occupational exposure to chemicals: A new challenge for employers

    Directory of Open Access Journals (Sweden)

    Jan Piotr Gromiec

    2013-10-01

    Full Text Available Employers are obliged to carry out and document the risk associated with the use of chemical substances. The best but the most expensive method is to measure workplace concentrations of chemicals. At present no "measureless" method for risk assessment is available in Poland, but predictive models for such assessments have been developed in some countries. The purpose of this work is to review and evaluate the applicability of selected predictive methods for assessing occupational inhalation exposure and related risk to check the compliance with Occupational Exposure Limits (OELs, as well as the compliance with REACH obligations. Based on the literature data HSE COSHH Essentials, EASE, ECETOC TRA, Stoffenmanager, and EMKG-Expo-Tool were evaluated. The data on validation of predictive models were also examined. It seems that predictive models may be used as a useful method for Tier 1 assessment of occupational exposure by inhalation. Since the levels of exposure are frequently overestimated, they should be considered as "rational worst cases" for selection of proper control measures. Bearing in mind that the number of available exposure scenarios and PROC categories is limited, further validation by field surveys is highly recommended. Predictive models may serve as a good tool for preliminary risk assessment and selection of the most appropriate risk control measures in Polish small and medium size enterprises (SMEs providing that they are available in the Polish language. This also requires an extensive training of their future users. Med Pr 2013;64(5:699–716

  17. Assessment of Aircrew Radiation Exposure by further measurements and model development

    International Nuclear Information System (INIS)

    Lewis, B. J.; Desormeaux, M.; Green, A. R.; Bennett, L. G. I.; Butler, A.; McCall, M.; Saez Vergara, J. C.

    2004-01-01

    A methodology is presented for collecting and analysing exposure measurements from galactic cosmic radiation using a portable equipment suite and encapsulating these data into a semi-empirical model/Predictive Code for Aircrew Radiation Exposure (PCAIRE) for the assessment of aircrew radiation exposure on any flight over the solar cycle. The PCAIRE code has been validated against integral route dose measurements at commercial aircraft altitudes during experimental flights made by various research groups over the past 5 y with code predictions typically within ±20% of the measured data. An empirical correlation, based on ground-level neutron monitoring data, is detailed further for estimation of aircrew exposure from solar particle events. The semi-empirical models have been applied to predict the annual and career exposure of a flight crew member using actual flight roster data, accounting for contributions from galactic radiation and several solar energetic-particle events over the period 1973-2002. (authors)

  18. Exposure assessment of mobile phone base station radiation in an outdoor environment using sequential surrogate modeling.

    Science.gov (United States)

    Aerts, Sam; Deschrijver, Dirk; Joseph, Wout; Verloock, Leen; Goeminne, Francis; Martens, Luc; Dhaene, Tom

    2013-05-01

    Human exposure to background radiofrequency electromagnetic fields (RF-EMF) has been increasing with the introduction of new technologies. There is a definite need for the quantification of RF-EMF exposure but a robust exposure assessment is not yet possible, mainly due to the lack of a fast and efficient measurement procedure. In this article, a new procedure is proposed for accurately mapping the exposure to base station radiation in an outdoor environment based on surrogate modeling and sequential design, an entirely new approach in the domain of dosimetry for human RF exposure. We tested our procedure in an urban area of about 0.04 km(2) for Global System for Mobile Communications (GSM) technology at 900 MHz (GSM900) using a personal exposimeter. Fifty measurement locations were sufficient to obtain a coarse street exposure map, locating regions of high and low exposure; 70 measurement locations were sufficient to characterize the electric field distribution in the area and build an accurate predictive interpolation model. Hence, accurate GSM900 downlink outdoor exposure maps (for use in, e.g., governmental risk communication and epidemiological studies) are developed by combining the proven efficiency of sequential design with the speed of exposimeter measurements and their ease of handling. Copyright © 2013 Wiley Periodicals, Inc.

  19. Using ecosystem modelling techniques in exposure assessments of radionuclides - an overview

    International Nuclear Information System (INIS)

    Kumblad, L.

    2005-01-01

    The risk to humans from potential releases from nuclear facilities is evaluated in safety assessments. Essential components of these assessments are exposure models, which estimate the transport of radionuclides in the environment, the uptake in biota, and transfer to humans. Recently, there has been a growing concern for radiological protection of the whole environment, not only humans, and a first attempt has been to employ model approaches based on stylized environments and transfer functions to biota based exclusively on bioconcentration factors (BCF). They are generally of a non-mechanistic nature and involve no knowledge of the actual processes involved, which is a severe limitation when assessing real ecosystems. in this paper, the possibility of using an ecological modelling approach as a complement or an alternative to the use of BCF-based models is discussed. The paper gives an overview of ecological and ecosystem modelling and examples of studies where ecosystem models have been used in association to ecological risk assessment studies for other pollutants than radionuclides. It also discusses the potential to use this technique in exposure assessments of radionuclides with a few examples from the safety assessment work performed by the Swedish nuclear fuel and waste management company (SKB). Finally there is a comparison of the characteristics of ecosystem models and traditionally exposure models for radionuclides used to estimate the radionuclide exposure of biota. The evaluation of ecosystem models already applied in safety assessments has shown that the ecosystem approach is possible to use to assess exposure to biota, and that it can handle many of the modelling problems identified related to BCF-models. The findings in this paper suggest that both national and international assessment frameworks for protection of the environment from ionising radiation would benefit from striving to adopt methodologies based on ecologically sound principles and

  20. An Exploratory Study: Assessment of Modeled Dioxin Exposure in Ceramic Art Studios (External Review Draft)

    Science.gov (United States)

    EPA has released an external review draft entitled, An Exploratory Study: Assessment of Modeled Dioxin Exposure in Ceramic Art Studios(External Review Draft). The public comment period and the external peer-review workshop are separate processes that provide opportunities ...

  1. Kriged and modeled ambient air levels of benzene in an urban environment: an exposure assessment study

    Directory of Open Access Journals (Sweden)

    Lai Dejian

    2011-03-01

    Full Text Available Abstract Background There is increasing concern regarding the potential adverse health effects of air pollution, particularly hazardous air pollutants (HAPs. However, quantifying exposure to these pollutants is problematic. Objective Our goal was to explore the utility of kriging, a spatial interpolation method, for exposure assessment in epidemiologic studies of HAPs. We used benzene as an example and compared census tract-level kriged predictions to estimates obtained from the 1999 U.S. EPA National Air Toxics Assessment (NATA, Assessment System for Population Exposure Nationwide (ASPEN model. Methods Kriged predictions were generated for 649 census tracts in Harris County, Texas using estimates of annual benzene air concentrations from 17 monitoring sites operating in Harris and surrounding counties from 1998 to 2000. Year 1999 ASPEN modeled estimates were also obtained for each census tract. Spearman rank correlation analyses were performed on the modeled and kriged benzene levels. Weighted kappa statistics were computed to assess agreement between discretized kriged and modeled estimates of ambient air levels of benzene. Results There was modest correlation between the predicted and modeled values across census tracts. Overall, 56.2%, 40.7%, 31.5% and 28.2% of census tracts were classified as having 'low', 'medium-low', 'medium-high' and 'high' ambient air levels of benzene, respectively, comparing predicted and modeled benzene levels. The weighted kappa statistic was 0.26 (95% confidence interval (CI = 0.20, 0.31, indicating poor agreement between the two methods. Conclusions There was a lack of concordance between predicted and modeled ambient air levels of benzene. Applying methods of spatial interpolation for assessing exposure to ambient air pollutants in health effect studies is hindered by the placement and number of existing stationary monitors collecting HAP data. Routine monitoring needs to be expanded if we are to use these data

  2. Assessment of human exposures

    Energy Technology Data Exchange (ETDEWEB)

    Lebret, E [RIVM-National Inst. of Public Health and Environmental Protection (Netherlands)

    1996-12-31

    This article describes some of the features of the assessment of human exposure to environmental pollutants in epidemiological studies. Since exposure assessment in air pollution epidemiology studies typically involve professionals from various backgrounds, interpretation of a concepts like `exposure` may vary. A brief descriptions is therefore given by way of introduction

  3. Assessment of human exposures

    Energy Technology Data Exchange (ETDEWEB)

    Lebret, E. [RIVM-National Inst. of Public Health and Environmental Protection (Netherlands)

    1995-12-31

    This article describes some of the features of the assessment of human exposure to environmental pollutants in epidemiological studies. Since exposure assessment in air pollution epidemiology studies typically involve professionals from various backgrounds, interpretation of a concepts like `exposure` may vary. A brief descriptions is therefore given by way of introduction

  4. Evaluation of three physiologically based pharmacokinetic (PBPK) modeling tools for emergency risk assessment after acute dichloromethane exposure

    NARCIS (Netherlands)

    Boerleider, R. Z.; Olie, J. D N; van Eijkeren, J. C H; Bos, P. M J; Hof, B. G H; de Vries, I.; Bessems, J. G M; Meulenbelt, J.; Hunault, C. C.

    2015-01-01

    Introduction: Physiologically based pharmacokinetic (PBPK) models may be useful in emergency risk assessment, after acute exposure to chemicals, such as dichloromethane (DCM). We evaluated the applicability of three PBPK models for human risk assessment following a single exposure to DCM: one model

  5. Dermal Exposure Assessment to Pesticides in Farming Systems in Developing Countries: Comparison of Models

    Directory of Open Access Journals (Sweden)

    Camilo Lesmes Fabian

    2015-04-01

    Full Text Available In the field of occupational hygiene, researchers have been working on developing appropriate methods to estimate human exposure to pesticides in order to assess the risk and therefore to take the due decisions to improve the pesticide management process and reduce the health risks. This paper evaluates dermal exposure models to find the most appropriate. Eight models (i.e., COSHH, DERM, DREAM, EASE, PHED, RISKOFDERM, STOFFENMANAGER and PFAM were evaluated according to a multi-criteria analysis and from these results five models (i.e., DERM, DREAM, PHED, RISKOFDERM and PFAM were selected for the assessment of dermal exposure in the case study of the potato farming system in the Andean highlands of Vereda La Hoya, Colombia. The results show that the models provide different dermal exposure estimations which are not comparable. However, because of the simplicity of the algorithm and the specificity of the determinants, the DERM, DREAM and PFAM models were found to be the most appropriate although their estimations might be more accurate if specific determinants are included for the case studies in developing countries.

  6. Modeling The Inhalation Exposure Pathway In Performance Assessment Of Geologic Radioactive Waste Repository At Yucca Mountain

    International Nuclear Information System (INIS)

    M.A. Wasiolek

    2006-01-01

    Inhalation exposure pathway modeling has recently been investigated as one of the tasks of the BIOPROTA Project (BIOPROTA 2005). BIOPROTA was set up to address the key uncertainties in long term assessments of contaminant releases into the environment arising from radioactive waste disposal. Participants of this international Project include national authorities and agencies, both regulators and operators, with responsibility for achieving safe and acceptable radioactive waste management. The objective of the inhalation task was to investigate the calculation of doses arising from inhalation of particles suspended from soils within which long-lived radionuclides, particularly alpha emitters, had accumulated. It was recognized that site-specific conditions influence the choice of conceptual model and input parameter values. Therefore, one of the goals of the task was to identify the circumstances in which different processes included in specific inhalation exposure pathway models were important. This paper discusses evaluation of processes and modeling assumptions specific to the proposed repository at Yucca Mountain as compared to the typical approaches and other models developed for different assessments and project specific contexts. Inhalation of suspended particulates that originate from contaminated soil is an important exposure pathway, particularly for exposure to actinides such as uranium, neptunium and plutonium. Radionuclide accumulation in surface soil arises from irrigation of soil with contaminated water over many years. The level of radionuclide concentration in surface soil depends on the assumed duration of irrigation. Irrigation duration is one of the parameters used on biosphere models and it depends on a specific assessment context. It is one of the parameters addressed in this paper from the point of view of assessment context for the proposed repository at Yucca Mountain. The preferred model for the assessment of inhalation exposure uses

  7. Validity of a traffic air pollutant dispersion model to assess exposure to fine particles.

    Science.gov (United States)

    Kostrzewa, Aude; Reungoat, Patrice; Raherison, Chantal

    2009-08-01

    Fine particles (PM(2.5)) are an important component of air pollution. Epidemiological studies have shown health effects due to ambient air particles, particularly allergies in children. Since the main difficulty is to determine exposure to such pollution, traffic air pollutant (TAP) dispersions models have been developed to improve the estimation of individual exposure levels. One such model, the ExTra index, has been validated for nitrogen oxide concentrations but not for other pollutants. The purpose of this study was to assess the validity of the ExTra index to assess PM(2.5) exposure. We compared PM(2.5) concentrations calculated by the ExTra index to reference measures (passive samplers situated under the covered part of the playground), in 15 schools in Bordeaux, in 2000. First, we collected the input data required by the ExTra index: background and local pollution depending on traffic, meteorology and topography. Second, the ExTra index was calculated for each school. Statistical analysis consisted of a graphic description; then, we calculated an intraclass correlation coefficient. Concentrations calculated with the ExTra index and the reference method were similar. The ExTra index underestimated exposure by 2.2 microg m(-3) on average compared to the reference method. The intraclass correlation coefficient was 0.85 and its 95% confidence interval was [0.62; 0.95]. The results suggest that the ExTra index provides an assessment of PM(2.5) exposure similar to that of the reference method. Although caution is required in interpreting these results owing to the small number of sites, the ExTra index could be a useful epidemiological tool for reconstructing individual exposure, an important challenge in epidemiology.

  8. The MULTIMEDIA exposure model as a risk assessment tool at LUST sites

    International Nuclear Information System (INIS)

    Bowers, R.B.

    1994-01-01

    In the course of characterizing Leaking Underground Storage Tank (LUST) sites in the Commonwealth, Virginia Department of Environmental Quality (VDEQ) regulations section 6.5.A.2.b of VR-680-13-02, requires that a risk assessment be performed which must address, among other issues, aqueous phase contaminant exposure levels to critical receptors. often, during the course of conducting such an assessment, the aqueous phase contaminant plume has not yet intercepted the critical down gradient receptor. Thus, the determination of the maximum potential exposure level to this receptor can only be made through the use of an appropriate fate and transport model. This paper focuses on an application of the saturated zone module of the USEPA's MULTIMEDIA Exposure Assessment model. The case study presented involves a LUST site in the Commonwealth, in which four critical receptors of leaded gasoline contaminated groundwater were identified. These receptors included three residential water wells and an intermittent stream. At this particular site, the aqueous phase contaminant plume had not yet reached any of the receptors; and the MULTIMEDIA model was employed to predict the steady-state aqueous phase concentrations with very favorable results

  9. Environmental fate and exposure models: advances and challenges in 21st century chemical risk assessment.

    Science.gov (United States)

    Di Guardo, Antonio; Gouin, Todd; MacLeod, Matthew; Scheringer, Martin

    2018-01-24

    Environmental fate and exposure models are a powerful means to integrate information on chemicals, their partitioning and degradation behaviour, the environmental scenario and the emissions in order to compile a picture of chemical distribution and fluxes in the multimedia environment. A 1995 pioneering book, resulting from a series of workshops among model developers and users, reported the main advantages and identified needs for research in the field of multimedia fate models. Considerable efforts were devoted to their improvement in the past 25 years and many aspects were refined; notably the inclusion of nanomaterials among the modelled substances, the development of models at different spatial and temporal scales, the estimation of chemical properties and emission data, the incorporation of additional environmental media and processes, the integration of sensitivity and uncertainty analysis in the simulations. However, some challenging issues remain and require research efforts and attention: the need of methods to estimate partition coefficients for polar and ionizable chemical in the environment, a better description of bioavailability in different environments as well as the requirement of injecting more ecological realism in exposure predictions to account for the diversity of ecosystem structures and functions in risk assessment. Finally, to transfer new scientific developments into the realm of regulatory risk assessment, we propose the formation of expert groups that compare, discuss and recommend model modifications and updates and help develop practical tools for risk assessment.

  10. ASSESSING CHILDREN'S EXPOSURES TO PESTICIDES: AN IMPORTANT APPLICATION OF THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION MODEL (SHEDS)

    Science.gov (United States)

    Accurately quantifying human exposures and doses of various populations to environmental pollutants is critical for the Agency to assess and manage human health risks. For example, the Food Quality Protection Act of 1996 (FQPA) requires EPA to consider aggregate human exposure ...

  11. From eyeballing to statistical modelling : methods for assessment of occupational exposure

    NARCIS (Netherlands)

    Kromhout, H.

    1994-01-01

    In this thesis methods for assessment of occupational exposure are evaluated and developed. These methods range from subjective methods (qualitative and semiquantitative) to more objective quantitative methods based on actual measurement of personal exposure to chemical and physical

  12. Generic Screening Models for Assessing Exposures to the Public and ICRP Reference Animals and Plants

    Energy Technology Data Exchange (ETDEWEB)

    Yankovich, Tamara L.; Proehl, Gerhard; Telleria, Diego [International Atomic Energy Agency, P.O. Box 100, 1400 Vienna (Austria); Berkovskyy, Volodymyr [Ukrainian Radiation Protection Institute (RPI), 53, Melnikova Street, 04050, Kiev (Ukraine)

    2014-07-01

    With the update of the IAEA Fundamental Safety Principles (SF-1) stating the objective to protect people and the environment from harmful effects of ionizing radiation, it has been necessary to update International Basic Safety Standards (BSS) on Radiation Protection and Safety of Radiation Sources and the underlying safety guides and technical documents to provide guidance on how this could be achieved in practice. The current paper provides an update on the status and plans to revise the IAEA Safety Report 'Generic Models for Use in Assessing the Impact of Discharges of Radioactive Substances to the Environment' (SRS 19) that was published in 2001. The models of SRS 19 (2001), which was focused on assessment of exposures to the public, is being expanded into three volumes that provide methodologies for screening assessments for the public, as well as for flora and fauna. The revised SRS 19 guide will ultimately facilitate the application of screening models for different levels of assessment using updated parameter values from database that have been developed as part of the IAEA's EMRAS (Environmental Modelling for Radiation Safety) and EMRAS II international model validation programmes. The scope of the revised SRS 19 covers prospective screening assessment of doses to the representative person and Reference Animals and Plants (RAPs), and will provide simple and robust assessment methods for radiological assessment related to planning and design, applying a graded approach. Tabulated screening coefficients and environmental dilution factors will be included for 825 radionuclides. The screening coefficients are developed assuming equilibrium conditions; they can be used to assess radiological impacts arising from routine discharges of radionuclides to terrestrial and aquatic receptors for planned exposure situations. Volumes 1 and 2 of the revised SRS 19 are at an advanced stage of completion and are focused on 'Screening Assessment of Public

  13. Multimedia radionuclide exposure assessment modeling. Annual report, October 1980-September 1981

    International Nuclear Information System (INIS)

    Whelan, G.; Onishi, Y.; Simmons, C.S.; Horst, T.W.; Gupta, S.K.; Orgill, M.M.; Newbill, C.A.

    1982-12-01

    Pacific Northwest Laboratory (PNL) and Los Alamos National Laboratory (LANL) are jointly developing a methodology for assessing exposures of the air, water, and plants to radionuclides as part of an overall development effort of a radionuclide disposal site evaluation methodology. Work in FY-1981 continued the development of the Multimedia Contaminant Environmental Exposure Assessment (MCEA) methodology and initiated an assessment of radionuclide migration in Los Alamos and Pueblo Canyons, New Mexico, using the methodology. The AIRTRAN model was completed, briefly tested, and documented. In addition, a literature search for existing validation data for AIRTRAN was performed. The feasibility and advisability of including the UNSAT moisture flow model as a submodel of the terrestrial code BIOTRAN was assessed. A preliminary application of the proposed MCEA methodology, as it related to the Mortandad-South Mortandad Canyon site in New Mexico is discussed. This preliminary application represented a scaled-down version of the methodology in which only the terrestrial, overland, and surface water components were used. An update describing the progress in the assessment of radionuclide migration in Los Alamos and Pueblo Canyons is presented. 38 references, 47 figures, 11 tables

  14. Annual report, October 1980-September 1981 Multimedia radionuclide exposure assessment modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Whelan, G.; Onishi, Y.; Simmons, C.S.; Horst, T.W.; Gupta, S.K.; Orgill, M.M.; Newbill, C.A.

    1982-12-01

    Pacific Northwest Laboratory (PNL) and Los Alamos National Laboratory (LANL) are jointly developing a methodology for assessing exposures of the air, water, and plants to radionuclides as part of an overall development effort of a radionuclide disposal site evaluation methodology. Work in FY-1981 continued the development of the Multimedia Contaminant Environmental Exposure Assessment (MCEA) methodology and initiated an assessment of radionuclide migration in Los Alamos and Pueblo Canyons, New Mexico, using the methodology. The AIRTRAN model was completed, briefly tested, and documented. In addition, a literature search for existing validation data for AIRTRAN was performed. The feasibility and advisability of including the UNSAT moisture flow model as a submodel of the terrestrial code BIOTRAN was assessed. A preliminary application of the proposed MCEA methodology, as it related to the Mortandad-South Mortandad Canyon site in New Mexico is discussed. This preliminary application represented a scaled-down version of the methodology in which only the terrestrial, overland, and surface water components were used. An update describing the progress in the assessment of radionuclide migration in Los Alamos and Pueblo Canyons is presented. 38 references, 47 figures, 11 tables.

  15. The Validity and Applicability of Using a Generic Exposure Assessment Model for Occupational Exposure to Nano-Objects and Their Aggregates and Agglomerates

    NARCIS (Netherlands)

    Bekker, Cindy; Voogd, Eef; Fransman, Wouter; Vermeulen, Roel

    2016-01-01

    BACKGROUND: Control banding can be used as a first-tier assessment to control worker exposure to nano-objects and their aggregates and agglomerates (NOAA). In a second tier, more advanced modelling approaches are needed to produce quantitative exposure estimates. As currently no general quantitative

  16. The validity and applicability of using a generic exposure assessment model for occupational exposure to nano-objects and their aggregates and agglomerates

    NARCIS (Netherlands)

    Bekker, C.; Voogd, E.; Fransman, W.; Vermeulen, R.

    2016-01-01

    Background: Control banding can be used as a first-tier assessment to control worker exposure to nano-objects and their aggregates and agglomerates (NOAA). In a second tier, more advanced modelling approaches are needed to produce quantitative exposure estimates. As currently no general quantitative

  17. Combining exposure and effect modeling into an integrated probabilistic environmental risk assessment for nanoparticles.

    Science.gov (United States)

    Jacobs, Rianne; Meesters, Johannes A J; Ter Braak, Cajo J F; van de Meent, Dik; van der Voet, Hilko

    2016-12-01

    There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To deal with uncertainty in the risk assessment effectively, probabilistic methods are advantageous. In the present study, the authors developed a method to model both the variability and the uncertainty in environmental risk assessment of ENPs. This method is based on the concentration ratio and the ratio of the exposure concentration to the critical effect concentration, both considered to be random. In this method, variability and uncertainty are modeled separately so as to allow the user to see which part of the total variation in the concentration ratio is attributable to uncertainty and which part is attributable to variability. The authors illustrate the use of the method with a simplified aquatic risk assessment of nano-titanium dioxide. The authors' method allows a more transparent risk assessment and can also direct further environmental and toxicological research to the areas in which it is most needed. Environ Toxicol Chem 2016;35:2958-2967. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC. © 2016 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals, Inc. on behalf of SETAC.

  18. Modeled exposure assessment via inhalation and dermal pathways to airborne semivolatile organic compounds (SVOCs) in residences.

    Science.gov (United States)

    Shi, Shanshan; Zhao, Bin

    2014-05-20

    Exposure to airborne semivolatile organic compounds (SVOCs) in indoor and outdoor environments of humans may lead to adverse health risks. Thus, we established a model to evaluate exposure to airborne SVOCs. In this model, SVOCs phase-specific concentrations were estimated by a kinetic partition model accounting for particle dynamics. The exposure pathways to airborne SVOCs included inhalation exposure to gas- and particle-phases, dermal exposure by direct gas-to-skin pathway and dermal exposure by direct particle deposition. Exposures of defined "reference people" to two typical classifications of SVOCs, one generated from both indoor and outdoor sources, represented by polycyclic aromatic hydrocarbons (PAHs), and the other generated mainly from only indoor sources, represented by di 2-ethylhexyl phthalate (DEHP), were analyzed as an example application of the model. For PAHs with higher volatility, inhalation exposure to gas-phase, ranging from 6.03 to 16.4 ng/kg/d, accounted for the most of the exposure to the airborne phases. For PAHs with lower volatility, inhalation exposure to particle-phase, ranging from 1.48 to 1.53 ng/kg/d, was the most important exposure pathway. As for DEHP, dermal exposure via direct gas-to-skin pathway was 460 ng/kg/d, which was the most striking exposure pathway when the barrier effect of clothing was neglected.

  19. Development of Toxicological Risk Assessment Models for Acute and Chronic Exposure to Pollutants

    Directory of Open Access Journals (Sweden)

    Elke S. Reichwaldt

    2016-08-01

    Full Text Available Alert level frameworks advise agencies on a sequence of monitoring and management actions, and are implemented so as to reduce the risk of the public coming into contact with hazardous substances. Their effectiveness relies on the detection of the hazard, but with many systems not receiving any regular monitoring, pollution events often go undetected. We developed toxicological risk assessment models for acute and chronic exposure to pollutants that incorporate the probabilities that the public will come into contact with undetected pollution events, to identify the level of risk a system poses in regards to the pollutant. As a proof of concept, we successfully demonstrated that the models could be applied to determine probabilities of acute and chronic illness types related to recreational activities in waterbodies containing cyanotoxins. Using the acute model, we identified lakes that present a ‘high’ risk to develop Day Away From Work illness, and lakes that present a ‘low’ or ‘medium’ risk to develop First Aid Cases when used for swimming. The developed risk models succeeded in categorising lakes according to their risk level to the public in an objective way. Modelling by how much the probability of public exposure has to decrease to lower the risks to acceptable levels will enable authorities to identify suitable control measures and monitoring strategies. We suggest broadening the application of these models to other contaminants.

  20. Exposure assessment of dioxins and dioxin-like PCBs in pasteurised bovine milk using probabilistic modelling.

    Science.gov (United States)

    Adekunte, Adefunke O; Tiwari, Brijesh K; O'Donnell, Colm P

    2010-09-01

    Quantitative exposure assessment is a useful technique to investigate the risk from contaminants in the food chain. The objective of this study was to develop a probabilistic exposure assessment model for dioxins (PCDD/Fs) and dioxin-like PCBs (DL-PCBs) in pasteurised bovine milk. Mean dioxins and DL-PCBs (non-ortho and mono-ortho PCBs) concentrations (pg WHO-TEQ g(-1)) in bovine milk were estimated as 0.06 ± 0.07 pg WHO-TEQ g(-1) for dioxins and 0.08 ± 0.07 pg WHO-TEQ g(-1) for DL-PCBs using Monte Carlo simulation. The simulated model estimated mean exposure for dioxins was 0.19 ± 0.29 pg WHO-TEQ kg(-1)bw d(-1) and 0.14 ± 0.22 pg WHO-TEQ kg(-1) bw d(-1) and for DL-PCBs was 0.25 ± 0.30 pg WHO-TEQ kg(-1) bw d(-1) and 0.19 ± 0.22 pg WHO-TEQ kg(-1) bw d(-1) for men and women, respectively. This study showed that the mean dioxins and DL-PCBs exposure from consumption of pasteurised bovine milk is below the provisional maximum tolerable monthly intake of 70 pg TEQ kg(-1) bw month(-1) (equivalent of 2.3 pg TEQ kg(-1) bw d(-1)) recommended by the Joint FAO/WHO Expert Committee on Food Additives and Contaminants (JECFA). Results from this study also showed that the estimated dioxins and DL-PCBs concentration in pasteurised bovine milk is comparable to those reported in previous studies. Copyright © 2010 Elsevier Ltd. All rights reserved.

  1. Assessment and improvement of biotransfer models to cow's milk and beef used in exposure assessment tools for organic pollutants.

    Science.gov (United States)

    Takaki, Koki; Wade, Andrew J; Collins, Chris D

    2015-11-01

    The aim of this study was to assess and improve the accuracy of biotransfer models for the organic pollutants (PCBs, PCDD/Fs, PBDEs, PFCAs, and pesticides) into cow's milk and beef used in human exposure assessment. Metabolic rate in cattle is known as a key parameter for this biotransfer, however few experimental data and no simulation methods are currently available. In this research, metabolic rate was estimated using existing QSAR biodegradation models of microorganisms (BioWIN) and fish (EPI-HL and IFS-HL). This simulated metabolic rate was then incorporated into the mechanistic cattle biotransfer models (RAIDAR, ACC-HUMAN, OMEGA, and CKow). The goodness of fit tests showed that RAIDAR, ACC-HUMAN, OMEGA model performances were significantly improved using either of the QSARs when comparing the new model outputs to observed data. The CKow model is the only one that separates the processes in the gut and liver. This model showed the lowest residual error of all the models tested when the BioWIN model was used to represent the ruminant metabolic process in the gut and the two fish QSARs were used to represent the metabolic process in the liver. Our testing included EUSES and CalTOX which are KOW-regression models that are widely used in regulatory assessment. New regressions based on the simulated rate of the two metabolic processes are also proposed as an alternative to KOW-regression models for a screening risk assessment. The modified CKow model is more physiologically realistic, but has equivalent usability to existing KOW-regression models for estimating cattle biotransfer of organic pollutants. Copyright © 2015. Published by Elsevier Ltd.

  2. Equivalent magnetic vector potential model for low-frequency magnetic exposure assessment

    Science.gov (United States)

    Diao, Y. L.; Sun, W. N.; He, Y. Q.; Leung, S. W.; Siu, Y. M.

    2017-10-01

    In this paper, a novel source model based on a magnetic vector potential for the assessment of induced electric field strength in a human body exposed to the low-frequency (LF) magnetic field of an electrical appliance is presented. The construction of the vector potential model requires only a single-component magnetic field to be measured close to the appliance under test, hence relieving considerable practical measurement effort—the radial basis functions (RBFs) are adopted for the interpolation of discrete measurements; the magnetic vector potential model can then be directly constructed by summing a set of simple algebraic functions of RBF parameters. The vector potentials are then incorporated into numerical calculations as the equivalent source for evaluations of the induced electric field in the human body model. The accuracy and effectiveness of the proposed model are demonstrated by comparing the induced electric field in a human model to that of the full-wave simulation. This study presents a simple and effective approach for modelling the LF magnetic source. The result of this study could simplify the compliance test procedure for assessing an electrical appliance regarding LF magnetic exposure.

  3. Assessing exposure to violence using multiple informants: application of hierarchical linear model.

    Science.gov (United States)

    Kuo, M; Mohler, B; Raudenbush, S L; Earls, F J

    2000-11-01

    The present study assesses the effects of demographic risk factors on children's exposure to violence (ETV) and how these effects vary by informants. Data on exposure to violence of 9-, 12-, and 15-year-olds were collected from both child participants (N = 1880) and parents (N = 1776), as part of the assessment of the Project on Human Development in Chicago Neighborhoods (PHDCN). A two-level hierarchical linear model (HLM) with multivariate outcomes was employed to analyze information obtained from these two different groups of informants. The findings indicate that parents generally report less ETV than do their children and that associations of age, gender, and parent education with ETV are stronger in the self-reports than in the parent reports. The findings support a multivariate approach when information obtained from different sources is being integrated. The application of HLM allows an assessment of interactions between risk factors and informants and uses all available data, including data from one informant when data from the other informant is missing.

  4. Modelling exposure opportunities

    DEFF Research Database (Denmark)

    Sabel, Clive E.; Gatrell, Anthony C.; Löytönen, Markku

    2000-01-01

    This paper addresses the issues surrounding an individual's exposure to potential environmental risk factors, which can be implicated in the aetiology of a disease. We hope to further elucidate the 'lag' or latency period between the initial exposure to potential pathogens and the physical...... boundaries.We use kernel estimation to model space-time patterns. Raised relative risk is assessed by adopting appropriate adjustments for the underlying population at risk, with the use of controls. Significance of the results is assessed using Monte Carlo simulation, and comparisons are made with results...

  5. An introduction to the indirect exposure assessment approach: modeling human exposure using microenvironmental measurements and the recent National Human Activity Pattern Survey.

    Science.gov (United States)

    Klepeis, N E

    1999-01-01

    Indirect exposure approaches offer a feasible and accurate method for estimating population exposures to indoor pollutants, including environmental tobacco smoke (ETS). In an effort to make the indirect exposure assessment approach more accessible to people in the health and risk assessment fields, this paper provides examples using real data from (italic>a(/italic>) a week-long personal carbon monoxide monitoring survey conducted by the author; and (italic>b(/italic>) the 1992 to 1994 National Human Activity Pattern Survey (NHAPS) for the United States. The indirect approach uses measurements of exposures in specific microenvironments (e.g., homes, bars, offices), validated microenvironmental models (based on the mass balance equation), and human activity pattern data obtained from questionnaires to predict frequency distributions of exposure for entire populations. This approach requires fewer resources than the direct approach to exposure assessment, for which the distribution of monitors to a representative sample of a given population is necessary. In the indirect exposure assessment approach, average microenvironmental concentrations are multiplied by the total time spent in each microenvironment to give total integrated exposure. By assuming that the concentrations encountered in each of 10 location categories are the same for different members of the U.S. population (i.e., the NHAPS respondents), the hypothetical contribution that ETS makes to the average 24-hr respirable suspended particle exposure for Americans working their main job is calculated in this paper to be 18 microg/m3. This article is an illustrative review and does not contain an actual exposure assessment or model validation. Images Figure 3 Figure 4 PMID:10350522

  6. Turbulent eddy diffusion models in exposure assessment - Determination of the eddy diffusion coefficient.

    Science.gov (United States)

    Shao, Yuan; Ramachandran, Sandhya; Arnold, Susan; Ramachandran, Gurumurthy

    2017-03-01

    The use of the turbulent eddy diffusion model and its variants in exposure assessment is limited due to the lack of knowledge regarding the isotropic eddy diffusion coefficient, D T . But some studies have suggested a possible relationship between D T and the air changes per hour (ACH) through a room. The main goal of this study was to accurately estimate D T for a range of ACH values by minimizing the difference between the concentrations measured and predicted by eddy diffusion model. We constructed an experimental chamber with a spatial concentration gradient away from the contaminant source, and conducted 27 3-hr long experiments using toluene and acetone under different air flow conditions (0.43-2.89 ACHs). An eddy diffusion model accounting for chamber boundary, general ventilation, and advection was developed. A mathematical expression for the slope based on the geometrical parameters of the ventilation system was also derived. There is a strong linear relationship between D T and ACH, providing a surrogate parameter for estimating D T in real-life settings. For the first time, a mathematical expression for the relationship between D T and ACH has been derived that also corrects for non-ideal conditions, and the calculated value of the slope between these two parameters is very close to the experimentally determined value. The values of D T obtained from the experiments are generally consistent with values reported in the literature. They are also independent of averaging time of measurements, allowing for comparison of values obtained from different measurement settings. These findings make the use of turbulent eddy diffusion models for exposure assessment in workplace/indoor environments more practical.

  7. Asbestos Exposure Assessment Database

    Science.gov (United States)

    Arcot, Divya K.

    2010-01-01

    Exposure to particular hazardous materials in a work environment is dangerous to the employees who work directly with or around the materials as well as those who come in contact with them indirectly. In order to maintain a national standard for safe working environments and protect worker health, the Occupational Safety and Health Administration (OSHA) has set forth numerous precautionary regulations. NASA has been proactive in adhering to these regulations by implementing standards which are often stricter than regulation limits and administering frequent health risk assessments. The primary objective of this project is to create the infrastructure for an Asbestos Exposure Assessment Database specific to NASA Johnson Space Center (JSC) which will compile all of the exposure assessment data into a well-organized, navigable format. The data includes Sample Types, Samples Durations, Crafts of those from whom samples were collected, Job Performance Requirements (JPR) numbers, Phased Contrast Microscopy (PCM) and Transmission Electron Microscopy (TEM) results and qualifiers, Personal Protective Equipment (PPE), and names of industrial hygienists who performed the monitoring. This database will allow NASA to provide OSHA with specific information demonstrating that JSC s work procedures are protective enough to minimize the risk of future disease from the exposures. The data has been collected by the NASA contractors Computer Sciences Corporation (CSC) and Wyle Laboratories. The personal exposure samples were collected from devices worn by laborers working at JSC and by building occupants located in asbestos-containing buildings.

  8. Development of a physiologically based pharmacokinetic model for assessment of human exposure to bisphenol A

    International Nuclear Information System (INIS)

    Yang, Xiaoxia; Doerge, Daniel R.; Teeguarden, Justin G.; Fisher, Jeffrey W.

    2015-01-01

    A previously developed physiologically based pharmacokinetic (PBPK) model for bisphenol A (BPA) in adult rhesus monkeys was modified to characterize the pharmacokinetics of BPA and its phase II conjugates in adult humans following oral ingestion. Coupled with in vitro studies on BPA metabolism in the liver and the small intestine, the PBPK model was parameterized using oral pharmacokinetic data with deuterated-BPA (d 6 -BPA) delivered in cookies to adult humans after overnight fasting. The availability of the serum concentration time course of unconjugated d 6 -BPA offered direct empirical evidence for the calibration of BPA model parameters. The recalibrated PBPK adult human model for BPA was then evaluated against published human pharmacokinetic studies with BPA. A hypothesis of decreased oral uptake was needed to account for the reduced peak levels observed in adult humans, where d 6 -BPA was delivered in soup and food was provided prior to BPA ingestion, suggesting the potential impact of dosing vehicles and/or fasting on BPA disposition. With the incorporation of Monte Carlo analysis, the recalibrated adult human model was used to address the inter-individual variability in the internal dose metrics of BPA for the U.S. general population. Model-predicted peak BPA serum levels were in the range of pM, with 95% of human variability falling within an order of magnitude. This recalibrated PBPK model for BPA in adult humans provides a scientific basis for assessing human exposure to BPA that can serve to minimize uncertainties incurred during extrapolations across doses and species. - Highlights: • A PBPK model predicts the kinetics of bisphenol A (BPA) in adult humans. • Serum concentrations of aglycone BPA are available for model calibration. • Model predicted peak BPA serum levels for adult humans were in the range of pM. • Model predicted 95% of human variability fell within an order of magnitude.

  9. Development of a physiologically based pharmacokinetic model for assessment of human exposure to bisphenol A

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoxia, E-mail: xiaoxia.yang@fda.hhs.gov [Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States); Doerge, Daniel R. [Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States); Teeguarden, Justin G. [Health Effects and Exposure Science, Pacific Northwest National Laboratory, Richland, WA 99352 (United States); Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR 97331 (United States); Fisher, Jeffrey W. [Division of Biochemical Toxicology, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079 (United States)

    2015-12-15

    A previously developed physiologically based pharmacokinetic (PBPK) model for bisphenol A (BPA) in adult rhesus monkeys was modified to characterize the pharmacokinetics of BPA and its phase II conjugates in adult humans following oral ingestion. Coupled with in vitro studies on BPA metabolism in the liver and the small intestine, the PBPK model was parameterized using oral pharmacokinetic data with deuterated-BPA (d{sub 6}-BPA) delivered in cookies to adult humans after overnight fasting. The availability of the serum concentration time course of unconjugated d{sub 6}-BPA offered direct empirical evidence for the calibration of BPA model parameters. The recalibrated PBPK adult human model for BPA was then evaluated against published human pharmacokinetic studies with BPA. A hypothesis of decreased oral uptake was needed to account for the reduced peak levels observed in adult humans, where d{sub 6}-BPA was delivered in soup and food was provided prior to BPA ingestion, suggesting the potential impact of dosing vehicles and/or fasting on BPA disposition. With the incorporation of Monte Carlo analysis, the recalibrated adult human model was used to address the inter-individual variability in the internal dose metrics of BPA for the U.S. general population. Model-predicted peak BPA serum levels were in the range of pM, with 95% of human variability falling within an order of magnitude. This recalibrated PBPK model for BPA in adult humans provides a scientific basis for assessing human exposure to BPA that can serve to minimize uncertainties incurred during extrapolations across doses and species. - Highlights: • A PBPK model predicts the kinetics of bisphenol A (BPA) in adult humans. • Serum concentrations of aglycone BPA are available for model calibration. • Model predicted peak BPA serum levels for adult humans were in the range of pM. • Model predicted 95% of human variability fell within an order of magnitude.

  10. CAirTOX, An inter-media transfer model for assessing indirect exposures to hazardous air contaminants

    International Nuclear Information System (INIS)

    McKone, T.E.

    1994-01-01

    Risk assessment is a quantitative evaluation of information on potential health hazards of environmental contaminants and the extent of human exposure to these contaminants. As applied to toxic chemical emissions to air, risk assessment involves four interrelated steps. These are (1) determination of source concentrations or emission characteristics, (2) exposure assessment, (3) toxicity assessment, and (4) risk characterization. These steps can be carried out with assistance from analytical models in order to estimate the potential risk associated with existing and future releases. CAirTOX has been developed as a spreadsheet model to assist in making these types of calculations. CAirTOX follows an approach that has been incorporated into the CalTOX model, which was developed for the California Department of Toxic Substances Control, With CAirTOX, we can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The capacity to explicitly address uncertainty has been incorporated into the model in two ways. First, the spreadsheet form of the model makes it compatible with Monte-Carlo add-on programs that are available for uncertainty analysis. Second, all model inputs are specified in terms of an arithmetic mean and coefficient of variation so that uncertainty analyses can be carried out

  11. Modelling the bioaccumulation of persistent organic pollutants in agricultural food chains for regulatory exposure assessment.

    Science.gov (United States)

    Takaki, Koki; Wade, Andrew J; Collins, Chris D

    2017-02-01

    New models for estimating bioaccumulation of persistent organic pollutants in the agricultural food chain were developed using recent improvements to plant uptake and cattle transfer models. One model named AgriSim was based on K OW regressions of bioaccumulation in plants and cattle, while the other was a steady-state mechanistic model, AgriCom. The two developed models and European Union System for the Evaluation of Substances (EUSES), as a benchmark, were applied to four reported food chain (soil/air-grass-cow-milk) scenarios to evaluate the performance of each model simulation against the observed data. The four scenarios considered were as follows: (1) polluted soil and air, (2) polluted soil, (3) highly polluted soil surface and polluted subsurface and (4) polluted soil and air at different mountain elevations. AgriCom reproduced observed milk bioaccumulation well for all four scenarios, as did AgriSim for scenarios 1 and 2, but EUSES only did this for scenario 1. The main causes of the deviation for EUSES and AgriSim were the lack of the soil-air-plant pathway and the ambient air-plant pathway, respectively. Based on the results, it is recommended that soil-air-plant and ambient air-plant pathway should be calculated separately and the K OW regression of transfer factor to milk used in EUSES be avoided. AgriCom satisfied the recommendations that led to the low residual errors between the simulated and the observed bioaccumulation in agricultural food chain for the four scenarios considered. It is therefore recommended that this model should be incorporated into regulatory exposure assessment tools. The model uncertainty of the three models should be noted since the simulated concentration in milk from 5th to 95th percentile of the uncertainty analysis often varied over two orders of magnitude. Using a measured value of soil organic carbon content was effective to reduce this uncertainty by one order of magnitude.

  12. Assessing frost damages using dynamic models in walnut trees: exposure rather than vulnerability controls frost risks.

    Science.gov (United States)

    Guillaume, Charrier; Isabelle, Chuine; Marc, Bonhomme; Thierry, Améglio

    2018-05-01

    Frost damages develop when exposure overtakes frost vulnerability. Frost risk assessment therefore needs dynamic simulation of frost hardiness using temperature and photoperiod in interaction with developmental stage. Two models, including or not the effect of photoperiod, were calibrated using five years of frost hardiness monitoring (2007-2012), in two locations (low and high elevation) for three walnut genotypes with contrasted phenology and maximum hardiness (Juglans regia cv Franquette, J. regia × nigra 'Early' and 'Late'). The photothermal model predicted more accurate values for all genotypes (efficiency = 0.879; Root Mean Standard Error Predicted (RMSEP) = 2.55 °C) than the thermal model (efficiency = 0.801; RMSEP = 3.24 °C). Predicted frost damages were strongly correlated to minimum temperature of the freezing events (ρ = -0.983) rather than actual frost hardiness (ρ = -0.515), or ratio of phenological stage completion (ρ = 0.336). Higher frost risks are consequently predicted during winter, at high elevation, whereas spring is only risky at low elevation in early genotypes exhibiting faster dehardening rate. However, early frost damages, although of lower value, may negatively affect fruit production the subsequent year (R 2  = 0.381, P = 0.057). These results highlight the interacting pattern between frost exposure and vulnerability at different scales and the necessity of intra-organ studies to understand the time course of frost vulnerability in flower buds along the winter. © 2017 John Wiley & Sons Ltd.

  13. Bayesian Algorithm Implementation in a Real Time Exposure Assessment Model on Benzene with Calculation of Associated Cancer Risks

    Directory of Open Access Journals (Sweden)

    Pavlos A. Kassomenos

    2009-02-01

    Full Text Available The objective of the current study was the development of a reliable modeling platform to calculate in real time the personal exposure and the associated health risk for filling station employees evaluating current environmental parameters (traffic, meteorological and amount of fuel traded determined by the appropriate sensor network. A set of Artificial Neural Networks (ANNs was developed to predict benzene exposure pattern for the filling station employees. Furthermore, a Physiology Based Pharmaco-Kinetic (PBPK risk assessment model was developed in order to calculate the lifetime probability distribution of leukemia to the employees, fed by data obtained by the ANN model. Bayesian algorithm was involved in crucial points of both model sub compartments. The application was evaluated in two filling stations (one urban and one rural. Among several algorithms available for the development of the ANN exposure model, Bayesian regularization provided the best results and seemed to be a promising technique for prediction of the exposure pattern of that occupational population group. On assessing the estimated leukemia risk under the scope of providing a distribution curve based on the exposure levels and the different susceptibility of the population, the Bayesian algorithm was a prerequisite of the Monte Carlo approach, which is integrated in the PBPK-based risk model. In conclusion, the modeling system described herein is capable of exploiting the information collected by the environmental sensors in order to estimate in real time the personal exposure and the resulting health risk for employees of gasoline filling stations.

  14. Bayesian algorithm implementation in a real time exposure assessment model on benzene with calculation of associated cancer risks.

    Science.gov (United States)

    Sarigiannis, Dimosthenis A; Karakitsios, Spyros P; Gotti, Alberto; Papaloukas, Costas L; Kassomenos, Pavlos A; Pilidis, Georgios A

    2009-01-01

    The objective of the current study was the development of a reliable modeling platform to calculate in real time the personal exposure and the associated health risk for filling station employees evaluating current environmental parameters (traffic, meteorological and amount of fuel traded) determined by the appropriate sensor network. A set of Artificial Neural Networks (ANNs) was developed to predict benzene exposure pattern for the filling station employees. Furthermore, a Physiology Based Pharmaco-Kinetic (PBPK) risk assessment model was developed in order to calculate the lifetime probability distribution of leukemia to the employees, fed by data obtained by the ANN model. Bayesian algorithm was involved in crucial points of both model sub compartments. The application was evaluated in two filling stations (one urban and one rural). Among several algorithms available for the development of the ANN exposure model, Bayesian regularization provided the best results and seemed to be a promising technique for prediction of the exposure pattern of that occupational population group. On assessing the estimated leukemia risk under the scope of providing a distribution curve based on the exposure levels and the different susceptibility of the population, the Bayesian algorithm was a prerequisite of the Monte Carlo approach, which is integrated in the PBPK-based risk model. In conclusion, the modeling system described herein is capable of exploiting the information collected by the environmental sensors in order to estimate in real time the personal exposure and the resulting health risk for employees of gasoline filling stations.

  15. Environmental tobacco smoke in designated smoking areas in the hospitality industry: exposure measurements, exposure modelling and policy assessment.

    Science.gov (United States)

    McNabola, A; Eyre, G J; Gill, L W

    2012-09-01

    Tobacco control policy has been enacted in many jurisdictions worldwide banning smoking in the workplace. In the hospitality sector many businesses such as bars, hotels and restaurants have installed designated smoking areas on their premises and allowance for such smoking areas has been made in the tobacco control legislation of many countries. An investigation was carried out into the level of exposure to environmental tobacco smoke (ETS) present in 8 pubs in Ireland which included designated smoking areas complying with two different definitions of a smoking area set out in Irish legislation. In addition, ETS exposure in a pub with a designated smoking area not in compliance with the legislation was also investigated. The results of this investigation showed that the two differing definitions of a smoking area present in pubs produced similar concentrations of benzene within smoking areas (5.1-5.4 μg/m(3)) but differing concentrations within the 'smoke-free' areas (1.42-3.01 μg/m(3)). Smoking areas in breach of legislative definitions were found to produce the highest levels of benzene in the smoking area (49.5 μg/m(3)) and 'smoke-free' area (7.68 μg/m(3)). 3D exposure modelling of hypothetical smoking areas showed that a wide range of ETS exposure concentrations were possible in smoking areas with the same floor area and same smoking rate but differing height to width and length to width ratios. The results of this investigation demonstrate that significant scope for improvement of ETS exposure concentrations in pubs and in smoking areas may exist by refining and improving the legislative definitions of smoking areas in law. Copyright © 2012 Elsevier Ltd. All rights reserved.

  16. Pathway analysis and exposure assessment: MEPAS modeling for nonradiological chemical contaminants at the Hanford Site

    International Nuclear Information System (INIS)

    Blanton, M.L.; Dirkes, R.; Buck, J.; Cooper, A.; Castieton, K.; Glantz, C.

    1995-01-01

    A Chemical Pathway Analysis and Exposure Assessment was performed by the Surface Environmental Surveillance Project (SESP). The SESP monitors air, surface water, sediment, agricultural products, vegetation, soil, and wildlife in order to assess onsite of offsite environmental impacts and offsite human health risk at the Hanford Site. The objectives of this study are (1) determine if a nonradiological chemical monitoring program is warranted for the Hanford Site, (2) ensure that the selection of surveillance parameters such as media, sampling location, and analytes are chosen in a manner that is scientifically sound and cost-efficient, and (3) identify specific nonradiological chemicals of concern (COC) for the Hanford Site. The basis for identification of COC for the Hanford Site was an extensive literature review. The model was also used to predict COC concentrations required onsite to achieve an offsite cancer incidence of 1 E-6 and a hazard quotient of 1.0. This study indicated that nonradiological chemical contamination occurring onsite does not pose a significant offsite human health risk. The highest cancer incidence to the offsite maximally exposed individual from COC was from arsenic (1.76E-1 0); the highest hazard quotient was chromium VI (1.48E-04)

  17. A PROBABILISTIC EXPOSURE ASSESSMENT FOR CHILDREN WHO CONTACT CCA-TREATED PLAYSETS AND DECKS USING THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION (SHEDS) MODEL FOR THE WOOD PRESERVATIVE EXPOSURE SCENARIO

    Science.gov (United States)

    The U.S. Environmental Protection Agency has conducted a probabilistic exposure and dose assessment on the arsenic (As) and chromium (Cr) components of Chromated Copper Arsenate (CCA) using the Stochastic Human Exposure and Dose Simulation model for wood preservatives (SHEDS-Wood...

  18. Annual individual hygienic assessment of natural exposure doses of the Altai territory model areas population

    Directory of Open Access Journals (Sweden)

    N. Yu. Potseluev

    2016-01-01

    Full Text Available The goal is to determine ionizing radiation natural sources exposure regularities of Altai Territory model areas population. The materials and methods. 11376 radon measurements, 1247 gamma radiation meas-urements in an open area and in residential and office buildings were performed, selection of 189 drinking water tests was carried out. Results. Complex radiation and hygienic examination of the region with the most large municipalities number with model areas allocation was conducted. The assessment of the Altai Territory population’s individual annual radiation doses from natural radionuclides has revealed a number of the regularities depending on the terrain’s ecological and geographical type. Following the research results, ranging the region territories taking into account of annual effective doses of the population from natural sources for 2009-2015 was carried out. The annual individual effective dose of the Altai Territory upland areas population presented by the highest values and ranges from 7.36 mSv / year to 8.19 mSv / year. Foothill regions of Altai and in Salair ridge are characterized by increased population exposure from natural sources. Here the dose ranges from 5.09 mSv / year to 6.22 mSv / year. Steppe and forest-steppe territories are characterized by the lowest level of the natural radiation which is ranging from 3.23 mSv / year to 4.11 mSv / year, that doesn’t exceed the all-Russian levels. Most of the hygienic radon equivalent equilibrium volume activity standards exceedances were registered in mountain and foothill areas buildings. A number of radon anomalies is revealed also in steppe areas. Med exceedances ranged from 203 ± 17.8 Bq / m3 to 480 ± 37.9 Bq / m3. Given the fact that most of these buildings belong to the administrative or educational institutions with an eight-hour working day, the dose of radiation for people there can be up to 10 mSv / year. Conclusion. Spreading of individual annual effective

  19. Exposure assessment and modeling of particulate matter for asthmatic children using personal nephelometers

    Science.gov (United States)

    Wu, Chang-Fu; Delfino, Ralph J.; Floro, Joshua N.; Quintana, Penelope J. E.; Samimi, Behzad S.; Kleinman, Michael T.; Allen, Ryan W.; Sally Liu, L.-J.

    It has been shown that acute exposures to particulate matter (PM) may exacerbate asthma in children. However, most epidemiological studies have relied on time-integrated PM measurements taken at a centrally located stationary monitoring sites. In this article, we characterized children's short-term personal exposures to PM 2.5 (PM with aerodynamic diameters size-selective inlet was used to estimate real-time PM 2.5 concentrations on 20 asthmatic children, inside and outside of their residences, and at a central site. The personal and indoor pDRs were operated passively, while the home outdoor and central site instruments were operated actively. The subjects received 29.2% of their exposures at school, even though they only spent 16.4% of their time there. More precise personal clouds were estimated for the home-indoor and home-outdoor microenvironments where PM concentrations were measured. The personal cloud increased with increasing activity levels and was higher during outdoor activities than during indoor activities. We built models to predict personal PM exposures based on either microenvironmental or central-site PM 2.5 measurements, and evaluated the modeled exposures against the actual personal measurements. A multiple regression model with central site PM concentration as the main predictor had a better prediction power ( R2=0.41) than a three-microenvironmental model ( R2=0.11). We further constructed a source-specific exposure model utilizing the time-space-activity information and the particle infiltration efficiencies (mean=0.72±0.15) calculated from a recursive mass balance model. It was estimated that the mean hourly personal exposures resulting from ambient, indoor-generated, and personal activity PM 2.5 were 11.1, 5.5, and 10.0 μg/m 3, respectively, when the modeling error was minimized. The high PM 2.5 exposure to personal activities reported in our study is likely due to children's more active lifestyle as compared with older adult subjects in

  20. Exposure levels, environmental fate modelling and human health risk assessment of lindane in Ghana

    International Nuclear Information System (INIS)

    Adu-Kumi, S.

    2011-01-01

    This thesis discusses an innovative approach of combining chemical trace analysis including the use of 13 C-labelled isotopes as internal and recovery standards) with multi-media modelling for assessing health risks of Lindane which is a persistent organic pollutant (POP) and a commercial formulated insecticide also known as Gamma-hexachlorocyclohexane (γ-HCH). Samples studied were background air, human breast milk, and edible fish (tilapia and catfish). The investigations focused on the exposure of the general population. For the first time levels and seasonal variation of Lindane, α-HCH and β-HCH in background air of Lake Bosumtwi, Kwabenya and East Legon in Ghana were studied with polyurethane foam based passive air samplers. Lindane (average concentration 53 pg m -3 ) was measured in all samples with (i) gas chromatography-mass spectrometer (GC-MS) and (ii) gas chromatography-mass spectrometer operated in electron ionization mode (GC-EI-MS). Agricultural application and revolatilisation from soils were main primary and secondary sources of HCH releases. Levels and variation of Lindane, α-HCH and β-HCH in pooled and individual human breast milk samples collected from lactating mothers countrywide were determined using a high-resolution gas chromatography interfaced with a high-resolution gas chromatography interfaced with a high-resolution mass spectrometer (HRGC-HRMS). This constitutes the first comprehensive nationwide human breast milk study of assessing risks of HCHs for the general population of Ghana. Mothers were selected from three major cities (Accra, Kumasi and Tamale) and three rural communities (Ada, Jachie/Pramso and Tolon) representing the Southern, Middle and Northern sectors respectively. The results of the study showed that the general population of Ghana is widely exposed to HCHs although the current levels are generally low; and also suggest that the usage pattern and exposure levels of Lindane vary among the various regions in Ghana.

  1. CSOIL 2000 an exposure model for human risk assessment of soil contamination. A model description

    NARCIS (Netherlands)

    Brand E; Otte PF; Lijzen JPA; LER

    2007-01-01

    This RIVM description of the CSOIL 2000 model deals, for the first time, with all aspects of the model. CSOIL 2000 can be used to derive intervention values. Intervention values are calculated for contaminated soil and represent a measure for determining when contaminated soil needs to be

  2. Evaluation of semi-generic PBTK modeling for emergency risk assessment after acute inhalation exposure to volatile hazardous chemicals

    NARCIS (Netherlands)

    Olie, J Daniël N; Bessems, Jos G; Clewell, Harvey J; Meulenbelt, Jan; Hunault, Claudine C

    BACKGROUND: Physiologically Based Toxicokinetic Models (PBTK) may facilitate emergency risk assessment after chemical incidents with inhalation exposure, but they are rarely used due to their relative complexity and skill requirements. We aimed to tackle this problem by evaluating a semi-generic

  3. Evaluation of semi-generic PBTK modeling for emergency risk assessment after acute inhalation exposure to volatile hazardous chemicals

    NARCIS (Netherlands)

    Olie, J. Daniël N; Bessems, Jos G.; Clewell, Harvey J.; Meulenbelt, Jan; Hunault, Claudine C.

    2015-01-01

    BACKGROUND: Physiologically Based Toxicokinetic Models (PBTK) may facilitate emergency risk assessment after chemical incidents with inhalation exposure, but they are rarely used due to their relative complexity and skill requirements. We aimed to tackle this problem by evaluating a semi-generic

  4. A model to systematically employ professional judgment in the Bayesian Decision Analysis for a semiconductor industry exposure assessment.

    Science.gov (United States)

    Torres, Craig; Jones, Rachael; Boelter, Fred; Poole, James; Dell, Linda; Harper, Paul

    2014-01-01

    Bayesian Decision Analysis (BDA) uses Bayesian statistics to integrate multiple types of exposure information and classify exposures within the exposure rating categorization scheme promoted in American Industrial Hygiene Association (AIHA) publications. Prior distributions for BDA may be developed from existing monitoring data, mathematical models, or professional judgment. Professional judgments may misclassify exposures. We suggest that a structured qualitative risk assessment (QLRA) method can provide consistency and transparency in professional judgments. In this analysis, we use a structured QLRA method to define prior distributions (priors) for BDA. We applied this approach at three semiconductor facilities in South Korea, and present an evaluation of the performance of structured QLRA for determination of priors, and an evaluation of occupational exposures using BDA. Specifically, the structured QLRA was applied to chemical agents in similar exposure groups to identify provisional risk ratings. Standard priors were developed for each risk rating before review of historical monitoring data. Newly collected monitoring data were used to update priors informed by QLRA or historical monitoring data, and determine the posterior distribution. Exposure ratings were defined by the rating category with the highest probability--i.e., the most likely. We found the most likely exposure rating in the QLRA-informed priors to be consistent with historical and newly collected monitoring data, and the posterior exposure ratings developed with QLRA-informed priors to be equal to or greater than those developed with data-informed priors in 94% of comparisons. Overall, exposures at these facilities are consistent with well-controlled work environments. That is, the 95th percentile of exposure distributions are ≤50% of the occupational exposure limit (OEL) for all chemical-SEG combinations evaluated; and are ≤10% of the limit for 94% of chemical-SEG combinations evaluated.

  5. Model for screening-level assessment of near-field human exposure to neutral organic chemicals released indoors.

    Science.gov (United States)

    Zhang, Xianming; Arnot, Jon A; Wania, Frank

    2014-10-21

    Screening organic chemicals for hazard and risk to human health requires near-field human exposure models that can be readily parametrized with available data. The integration of a model of human exposure, uptake, and bioaccumulation into an indoor mass balance model provides a quantitative framework linking emissions in indoor environments with human intake rates (iRs), intake fractions (iFs) and steady-state concentrations in humans (C) through consideration of dermal permeation, inhalation, and nondietary ingestion exposure pathways. Parameterized based on representative indoor and adult human characteristics, the model is applied here to 40 chemicals of relevance in the context of human exposure assessment. Intake fractions and human concentrations (C(U)) calculated with the model based on a unit emission rate to air for these 40 chemicals span 2 and 5 orders of magnitude, respectively. Differences in priority ranking based on either iF or C(U) can be attributed to the absorption, biotransformation and elimination processes within the human body. The model is further applied to a large data set of hypothetical chemicals representative of many in-use chemicals to show how the dominant exposure pathways, iF and C(U) change as a function of chemical properties and to illustrate the capacity of the model for high-throughput screening. These simulations provide hypotheses for the combination of chemical properties that may result in high exposure and internal dose. The model is further exploited to highlight the role human contaminant uptake plays in the overall fate of certain chemicals indoors and consequently human exposure.

  6. A model to assess exposure from releases of radioactivity into the seas of northern Europe

    International Nuclear Information System (INIS)

    Clark, M.J.; Webb, G.A.M.

    1981-01-01

    A regional marine model is described which can be used to estimate the exposure of populations as a result of the discharge of radioactive effluents into the coastal waters of northern Europe. The model simulates the dispersion of radionuclides in marine waters, their interaction with marine sediments and the concentration mechanisms occurring in seafoods. A local/regional interface is included whereby releases are assumed to first enter a local marine compartment before widespread dispersion in coastal waters. Depletion mechanisms operate within both the local and regional environments influencing the fraction of radionuclide release which contributes to collective exposure. In general, results of the regional model are expressed as collective intakes of activity from ingestion of marine seafoods. These quantities can be converted into collective doses per unit discharge, given a knowledge of local depletion factors and the dose per unit intake of radionuclides. Results for caesium-137 and plutonium-239 released into United Kingdom coastal waters are discussed. (author)

  7. Indirect human exposure assessment of airborne lead deposited on soil via a simplified fate and speciation modelling approach.

    Science.gov (United States)

    Pizzol, Massimo; Bulle, Cécile; Thomsen, Marianne

    2012-04-01

    In order to estimate the total exposure to the lead emissions from a municipal waste combustion plant in Denmark, the indirect pathway via ingestion of lead deposited on soil has to be quantified. Multi-media fate models developed for both Risk Assessment (RA) and Life Cycle Assessment (LCA) can be used for this purpose, but present high uncertainties in the assessment of metal's fate. More sophisticated and metal-specific geochemical models exist, that could lower the uncertainties by e.g. accounting for metal speciation, but they require a large amount of data and are unpractical to combine broadly with other fate and dispersion models. In this study, a Simplified Fate & Speciation Model (SFSM) is presented, that is based on the parsimony principle: "as simple as possible, as complex as needed", and that can be used for indirect human exposure assessment in different context like RA and regionalized LCA. SFSM couples traditional multi-media mass balances with empirical speciation models in a tool that has a simple theoretical framework and that is not data-intensive. The model calculates total concentration, dissolved concentration, and free ion activity of Cd, Cu, Ni, Pb and Zn in different soil layers, after accounting for metal deposition and dispersion. The model is tested for these five metals by using data from peer reviewed literature. Results show good accordance between measured and calculated values (factor of 3). The model is used to predict the human exposure via soil to lead initially emitted into air by the waste combustion plant and both the lead cumulative exposure and intake fraction are calculated. Copyright © 2012 Elsevier B.V. All rights reserved.

  8. Human Exposure Assessment for Air Pollution.

    Science.gov (United States)

    Han, Bin; Hu, Li-Wen; Bai, Zhipeng

    2017-01-01

    Assessment of human exposure to air pollution is a fundamental part of the more general process of health risk assessment. The measurement methods for exposure assessment now include personal exposure monitoring, indoor-outdoor sampling, mobile monitoring, and exposure assessment modeling (such as proximity models, interpolation model, air dispersion models, and land-use regression (LUR) models). Among these methods, personal exposure measurement is considered to be the most accurate method of pollutant exposure assessment until now, since it can better quantify observed differences and better reflect exposure among smaller groups of people at ground level. And since the great differences of geographical environment, source distribution, pollution characteristics, economic conditions, and living habits, there is a wide range of differences between indoor, outdoor, and individual air pollution exposure in different regions of China. In general, the indoor particles in most Chinese families comprise infiltrated outdoor particles, particles generated indoors, and a few secondary organic aerosol particles, and in most cases, outdoor particle pollution concentrations are a major contributor to indoor concentrations in China. Furthermore, since the time, energy, and expense are limited, it is difficult to measure the concentration of pollutants for each individual. In recent years, obtaining the concentration of air pollutants by using a variety of exposure assessment models is becoming a main method which could solve the problem of the increasing number of individuals in epidemiology studies.

  9. The landscape of existing models for high-throughput exposure assessment

    DEFF Research Database (Denmark)

    Jolliet, O.; Fantke, Peter; Huang, L.

    2017-01-01

    and ability to easily handle large datasets. For building materials a series of diffusion-based models have been developed to predict the chemicals emissions from building materials to indoor air, but existing models require complex analytical or numerical solutions, which are not suitable for LCA or HTS...... applications. Thus, existing model solutions needed to be simplified for application in LCA and HTS, and a parsimonious model has been developed by Huang et al. (2017) to address this need. For SVOCs, simplified solutions do exist, assuming constant SVOC concentrations in building materials and steadystate...... for skin permeation and volatilization as competing processes and that requires a limited number of readily available physiochemical properties would be suitable for LCA and HTS purposes. Thus, the multi-pathway exposure model for chemicals in cosmetics developed by Ernstoff et al.constitutes a suitable...

  10. Assessment and improvement of biotransfer models to cow’s milk and beef used in exposure assessment tools for organic pollutants

    OpenAIRE

    Takaki, Koki; Wade, Andrew J.; Collins, Christopher D.

    2015-01-01

    The aim of this study was to assess and improve the accuracy of biotransfer models for the organic pollutants (PCBs, PCDD/Fs, PBDEs, PFCAs, and pesticides) into cow’s milk and beef used in human exposure assessment. Metabolic rate in cattle is known as a key parameter for this biotransfer, however few experimental data and no simulation methods are currently available. In this research, metabolic rate was estimated using existing QSAR biodegradation models of microorganisms (BioWIN) and fish ...

  11. Analysis of intervention strategies for inhalation exposure to polycyclic aromatic hydrocarbons and associated lung cancer risk based on a Monte Carlo population exposure assessment model.

    Science.gov (United States)

    Zhou, Bin; Zhao, Bin

    2014-01-01

    It is difficult to evaluate and compare interventions for reducing exposure to air pollutants, including polycyclic aromatic hydrocarbons (PAHs), a widely found air pollutant in both indoor and outdoor air. This study presents the first application of the Monte Carlo population exposure assessment model to quantify the effects of different intervention strategies on inhalation exposure to PAHs and the associated lung cancer risk. The method was applied to the population in Beijing, China, in the year 2006. Several intervention strategies were designed and studied, including atmospheric cleaning, smoking prohibition indoors, use of clean fuel for cooking, enhancing ventilation while cooking and use of indoor cleaners. Their performances were quantified by population attributable fraction (PAF) and potential impact fraction (PIF) of lung cancer risk, and the changes in indoor PAH concentrations and annual inhalation doses were also calculated and compared. The results showed that atmospheric cleaning and use of indoor cleaners were the two most effective interventions. The sensitivity analysis showed that several input parameters had major influence on the modeled PAH inhalation exposure and the rankings of different interventions. The ranking was reasonably robust for the remaining majority of parameters. The method itself can be extended to other pollutants and in different places. It enables the quantitative comparison of different intervention strategies and would benefit intervention design and relevant policy making.

  12. Analysis of intervention strategies for inhalation exposure to polycyclic aromatic hydrocarbons and associated lung cancer risk based on a Monte Carlo population exposure assessment model.

    Directory of Open Access Journals (Sweden)

    Bin Zhou

    Full Text Available It is difficult to evaluate and compare interventions for reducing exposure to air pollutants, including polycyclic aromatic hydrocarbons (PAHs, a widely found air pollutant in both indoor and outdoor air. This study presents the first application of the Monte Carlo population exposure assessment model to quantify the effects of different intervention strategies on inhalation exposure to PAHs and the associated lung cancer risk. The method was applied to the population in Beijing, China, in the year 2006. Several intervention strategies were designed and studied, including atmospheric cleaning, smoking prohibition indoors, use of clean fuel for cooking, enhancing ventilation while cooking and use of indoor cleaners. Their performances were quantified by population attributable fraction (PAF and potential impact fraction (PIF of lung cancer risk, and the changes in indoor PAH concentrations and annual inhalation doses were also calculated and compared. The results showed that atmospheric cleaning and use of indoor cleaners were the two most effective interventions. The sensitivity analysis showed that several input parameters had major influence on the modeled PAH inhalation exposure and the rankings of different interventions. The ranking was reasonably robust for the remaining majority of parameters. The method itself can be extended to other pollutants and in different places. It enables the quantitative comparison of different intervention strategies and would benefit intervention design and relevant policy making.

  13. Meta-modeling of the pesticide fate model MACRO for groundwater exposure assessments using artificial neural networks

    Science.gov (United States)

    Stenemo, Fredrik; Lindahl, Anna M. L.; Gärdenäs, Annemieke; Jarvis, Nicholas

    2007-08-01

    Several simple index methods that use easily accessible data have been developed and included in decision-support systems to estimate pesticide leaching across larger areas. However, these methods often lack important process descriptions (e.g. macropore flow), which brings into question their reliability. Descriptions of macropore flow have been included in simulation models, but these are too complex and demanding for spatial applications. To resolve this dilemma, a neural network simulation meta-model of the dual-permeability macropore flow model MACRO was created for pesticide groundwater exposure assessment. The model was parameterized using pedotransfer functions that require as input the clay and sand content of the topsoil and subsoil, and the topsoil organic carbon content. The meta-model also requires the topsoil pesticide half-life and the soil organic carbon sorption coefficient as input. A fully connected feed-forward multilayer perceptron classification network with two hidden layers, linked to fully connected feed-forward multilayer perceptron neural networks with one hidden layer, trained on sub-sets of the target variable, was shown to be a suitable meta-model for the intended purpose. A Fourier amplitude sensitivity test showed that the model output (the 80th percentile average yearly pesticide concentration at 1 m depth for a 20 year simulation period) was sensitive to all input parameters. The two input parameters related to pesticide characteristics (i.e. soil organic carbon sorption coefficient and topsoil pesticide half-life) were the most influential, but texture in the topsoil was also quite important since it was assumed to control the mass exchange coefficient that regulates the strength of macropore flow. This is in contrast to models based on the advection-dispersion equation where soil texture is relatively unimportant. The use of the meta-model is exemplified with a case-study where the spatial variability of pesticide leaching is

  14. Development of a new modelling tool (FACET) to assess exposure to chemical migrants from food packaging.

    Science.gov (United States)

    Oldring, P K T; O'Mahony, C; Dixon, J; Vints, M; Mehegan, J; Dequatre, C; Castle, L

    2014-01-01

    The approach used to obtain European Union-wide data on the usage and concentration of substances in different food packaging materials is described. Statistics were collected on pack sizes and market shares for the different materials used to package different food groups. The packaging materials covered were plastics (both flexible and rigid), metal containers, light metal packaging, paper and board, as well as the adhesives and inks used on them. An explanation as to how these data are linked in various ways in the FACET exposure modelling tool is given as well as an overview of the software along with examples of the intermediate tables of data. The example of bisphenol A (BPA), used in resins that may be incorporated into some coatings for canned foodstuffs, is used to illustrate how the data in FACET are combined to produce concentration distributions. Such concentration distributions are then linked probabilistically to the amounts of each food item consumed, as recorded in national food consumption survey diaries, in order to estimate exposure to packaging migrants. Estimates of exposure are at the level of the individual consumer and thus can be expressed for various percentiles of different populations and subpopulations covered by the national dietary surveys.

  15. Evaluation of semi-generic PBTK modeling for emergency risk assessment after acute inhalation exposure to volatile hazardous chemicals.

    Science.gov (United States)

    Olie, J Daniël N; Bessems, Jos G; Clewell, Harvey J; Meulenbelt, Jan; Hunault, Claudine C

    2015-08-01

    Physiologically Based Toxicokinetic Models (PBTK) may facilitate emergency risk assessment after chemical incidents with inhalation exposure, but they are rarely used due to their relative complexity and skill requirements. We aimed to tackle this problem by evaluating a semi-generic PBTK model built in MS Excel for nine chemicals that are widely-used and often released in a chemical incident. The semi-generic PBTK model was used to predict blood concentration-time curves using inhalation exposure scenarios from human volunteer studies, case reports and hypothetical exposures at Emergency Response Planning Guideline, Level 3 (ERPG-3) levels.(2) Predictions using this model were compared with measured blood concentrations from volunteer studies or case reports, as well as blood concentrations predicted by chemical-specific models. The performances of the semi-generic model were evaluated on biological rationale, accuracy, and ease of use and range of application. Our results indicate that the semi-generic model can be easily used to predict blood levels for eight out of nine parent chemicals (dichloromethane, benzene, xylene, styrene, toluene, isopropanol trichloroethylene and tetrachloroethylene). However, for methanol, 2-propanol and dichloromethane the semi-generic model could not cope with the endogenous production of methanol and of acetone (being a metabolite of 2-propanol) nor could it simulate the formation of HbCO, which is one of the toxic end-points of dichloromethane. The model is easy and intuitive to use by people who are not so familiar with toxicokinetic models. A semi-generic PBTK modeling approach can be used as a 'quick-and-dirty' method to get a crude estimate of the exposure dose. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. PARAMETER EVALUATION AND MODEL VALIDATION OF OZONE EXPOSURE ASSESSMENT USING HARVARD SOUTHERN CALIFORNIA CHRONIC OZONE EXPOSURE STUDY DATA

    Science.gov (United States)

    To examine factors influencing long-term ozone exposures by children living in urban communities, we analyzed longitudinal data on personal, indoor, and outdoor ozone concentrations as well as related housing and other questionnaire information collected in the one-year-long Harv...

  17. Dynamic model for the assessment of radiological exposure to marine biota

    Energy Technology Data Exchange (ETDEWEB)

    Vives i Batlle, J. [Westlakes Scientific Consulting Ltd, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria CA24 3LN (United Kingdom)], E-mail: jordi.vives@westlakes.ac.uk; Wilson, R.C.; Watts, S.J.; Jones, S.R.; McDonald, P.; Vives-Lynch, S. [Westlakes Scientific Consulting Ltd, The Princess Royal Building, Westlakes Science and Technology Park, Moor Row, Cumbria CA24 3LN (United Kingdom)

    2008-11-15

    A generic approach has been developed to simulate dynamically the uptake and turnover of radionuclides by marine biota. The approach incorporates a three-compartment biokinetic model based on first order linear kinetics, with interchange rates between the organism and its surrounding environment. Model rate constants are deduced as a function of known parameters: biological half-lives of elimination, concentration factors and a sample point of the retention curve, allowing for the representation of multi-component release. The new methodology has been tested and validated in respect of non-dynamic assessment models developed for regulatory purposes. The approach has also been successfully tested against research dynamic models developed to represent the uptake of technetium and radioiodine by lobsters and winkles. Assessments conducted on two realistic test scenarios demonstrated the importance of simulating time-dependency for ecosystems in which environmental levels of radionuclides are not in equilibrium.

  18. Optimum modellings of atmospheric diffusion of radioactive effluents and exposure doses in the accident consequence assessment (Level 3 PSA)

    International Nuclear Information System (INIS)

    Kim, Byung Woo; Lee, Young Bok; Han, Moon Hee; Kim, Eun Han; Suh, Kyung Suk; Hwang, Won Tae

    1992-12-01

    Atmospheric diffusion and exposure strongly dependent on the environment were firstly considered in the full spectrum of accident consequence assessment to establish based on Korean conditions. An optimum weather category based on Korean climate and site-specific meteorology of Kori region was established by statistical analysis of measured data for 10 years. And a trajectory model was selected as the optimal one in the ACA by reviewing several existing diffusion models. Following aspects were considered in this selection as availability of meteorological data, ability to treat the change to wind direction, easy applicability of the model, and restriction of CPU time and core memory in current computers. Numerical integration method of our own was selected as the optimal dose assessment tool of external exposure. Unit dose rate was firstly computed with this method as the function of energy level of radionuclide, size of lattice, and distance between source and receptor, and then the results were rearranged as the data library for the rapid access to the ACA run. Dynamic ecosystem modelling has been done in order to estimate the seasonal variation of radioactivity for the assessment of ingestion exposure, considering Korean ingestion behavior, agricultural practice and the transportation. There is a lot of uncertainty in a countermeasure model due to the assumed values of parameters such as fraction of population with different shielding factor and driving speed. A new countermeasure model was developed using the concept of fuzzy set theory, since it provided the mathematical tools which could characterize the uncertainty involved in countermeasure modelling. (Author)

  19. A polygon-based modeling approach to assess exposure of resources and assets to wildfire

    Science.gov (United States)

    Matthew P. Thompson; Joe Scott; Jeffrey D. Kaiden; Julie W. Gilbertson-Day

    2013-01-01

    Spatially explicit burn probability modeling is increasingly applied to assess wildfire risk and inform mitigation strategy development. Burn probabilities are typically expressed on a per-pixel basis, calculated as the number of times a pixel burns divided by the number of simulation iterations. Spatial intersection of highly valued resources and assets (HVRAs) with...

  20. Assessment of body doses from photon exposures using human voxel models

    International Nuclear Information System (INIS)

    Zankl, M.; Fill, U.; Petoussi-Henss, N.; Regulla, D.

    2000-01-01

    For the scope of risk assessment in protection against ionising radiation (occupational, environmental and medical) it is necessary to determine the radiation dose to specific body organs and tissues. For this purpose, a series of models of the human body were designed in the past, together with computer codes simulating the radiation transport and energy deposition in the body. Most of the computational body models in use are so-called mathematical models; the most famous is the MIRD-5 phantom developed at Oak Ridge National Laboratory. In the 1980s, a new generation of human body models was introduced at GSF, constructed from whole body CT data. Due to being constructed from image data of real persons, these 'voxel models' offer an improved realism of external and internal shape of the body and its organs, compared to MIRD-type models. Comparison of dose calculations involving voxel models with respective dose calculations for MIRD-type models revealed that the deviation of the individual anatomy from that described in the MIRD-type models indeed introduces significant deviations of the calculated organ doses. Specific absorbed fractions of energy released in a source organ due to incorporated activity which are absorbed in target organs may differ by more than an order of magnitude between different body models; for external photon irradiation, the discrepancies are more moderate. (author)

  1. A dynamic urban air pollution population exposure assessment study using model and population density data derived by mobile phone traffic

    Science.gov (United States)

    Gariazzo, Claudio; Pelliccioni, Armando; Bolignano, Andrea

    2016-04-01

    A dynamic city-wide air pollution exposure assessment study has been carried out for the urban population of Rome, Italy, by using time resolved population distribution maps, derived by mobile phone traffic data, and modelled air pollutants (NO2, O3 and PM2.5) concentrations obtained by an integrated air dispersion modelling system. More than a million of persons were tracked during two months (March and April 2015) for their position within the city and its surroundings areas, with a time resolution of 15 min and mapped over an irregular grid system with a minimum resolution of 0.26 × 0.34 Km2. In addition, demographics information (as gender and age ranges) were available in a separated dataset not connected with the total population one. Such BigData were matched in time and space with air pollution model results and then used to produce hourly and daily resolved cumulative population exposures during the studied period. A significant mobility of population was identified with higher population densities in downtown areas during daytime increasing of up to 1000 people/Km2 with respect to nigh-time one, likely produced by commuters, tourists and working age population. Strong variability (up to ±50% for NO2) of population exposures were detected as an effect of both mobility and time/spatial changing in pollutants concentrations. A comparison with the correspondent stationary approach based on National Census data, allows detecting the inability of latter in estimating the actual variability of population exposure. Significant underestimations of the amount of population exposed to daily PM2.5 WHO guideline was identified for the Census approach. Very small differences (up to a few μg/m3) on exposure were detected for gender and age ranges population classes.

  2. A study on modeling nitrogen dioxide concentrations using land-use regression and conventionally used exposure assessment methods

    Science.gov (United States)

    Choi, Giehae; Bell, Michelle L.; Lee, Jong-Tae

    2017-04-01

    The land-use regression (LUR) approach to estimate the levels of ambient air pollutants is becoming popular due to its high validity in predicting small-area variations. However, only a few studies have been conducted in Asian countries, and much less research has been conducted on comparing the performances and applied estimates of different exposure assessments including LUR. The main objectives of the current study were to conduct nitrogen dioxide (NO2) exposure assessment with four methods including LUR in the Republic of Korea, to compare the model performances, and to estimate the empirical NO2 exposures of a cohort. The study population was defined as the year 2010 participants of a government-supported cohort established for bio-monitoring in Ulsan, Republic of Korea. The annual ambient NO2 exposures of the 969 study participants were estimated with LUR, nearest station, inverse distance weighting, and ordinary kriging. Modeling was based on the annual NO2 average, traffic-related data, land-use data, and altitude of the 13 regularly monitored stations. The final LUR model indicated that area of transportation, distance to residential area, and area of wetland were important predictors of NO2. The LUR model explained 85.8% of the variation observed in the 13 monitoring stations of the year 2009. The LUR model outperformed the others based on leave-one out cross-validation comparing the correlations and root-mean square error. All NO2 estimates ranged from 11.3-18.0 ppb, with that of LUR having the widest range. The NO2 exposure levels of the residents differed by demographics. However, the average was below the national annual guidelines of the Republic of Korea (30 ppb). The LUR models showed high performances in an industrial city in the Republic of Korea, despite the small sample size and limited data. Our findings suggest that the LUR method may be useful in similar settings in Asian countries where the target region is small and availability of data is

  3. TOWARDS RELIABLE AND COST-EFFECTIVE OZONE EXPOSURE ASSESSMENT: PARAMETER EVALUATION AND MODEL VALIDATION USING THE HARVARD SOUTHERN CALIFORNIA CHRONIC OZONE EXPOSURE STUDY DATA

    Science.gov (United States)

    Accurate assessment of chronic human exposure to atmospheric criteria pollutants, such as ozone, is critical for understanding human health risks associated with living in environments with elevated ambient pollutant concentrations. In this study, we analyzed a data set from a...

  4. GIS-based models for ambient PM exposure and health impact assessment for the UK

    International Nuclear Information System (INIS)

    Stedman, John R; Grice, Susannah; Kent, Andrew; Cooke, Sally

    2009-01-01

    GIS-based models have been developed to map ambient PM 10 and PM 25 mass concentrations across the UK. The resulting maps are used for the assessments of air quality required by the EU ambient air quality directives, health impact assessment and the development of UK air quality policy. Maps are presented for 2006 along with projections to 2020. The largest single contribution to the UK population-weighted mean annual mean background concentrations of PM 10 in 2006 is estimated to be from secondary PM (43%), followed by the contribution from primary PM (24%). Concentrations are predicted to decline by 15% for PM 10 and 13% for PM 25 over the period from 2006 to 2020. The extent of exceedence of the 24-hour limit value is predicted to decline from 1.9% to 0.1% of urban major roads over the same period. The potential health benefits of reductions in ambient PM are large. A reduction in concentration of 0.93 μg m -3 as a result of a possible package of measures has been estimated within the UK Air Quality Strategy to result in a reduction in life years lost of approximately 2 - 4 million over a period of 100 years.

  5. Probabilistic dietary exposure models

    NARCIS (Netherlands)

    Boon, Polly E.; Voet, van der H.

    2015-01-01

    Exposure models are used to calculate the amount of potential harmful chemicals ingested by a human population. Examples of harmful chemicals are residues of pesticides, chemicals entering food from the environment (such as dioxins, cadmium, lead, mercury), and chemicals that are generated via

  6. Integrated fate modeling for exposure assessment of produced water on the Sable Island Bank (Scotian shelf, Canada).

    Science.gov (United States)

    Berry, Jody A; Wells, Peter G

    2004-10-01

    Produced water is the largest waste discharge from the production phase of oil and gas wells. Produced water is a mixture of reservoir formation water and production chemicals from the separation process. This creates a chemical mixture that has several components of toxic concern, ranging from heavy metals to soluble hydrocarbons. Analysis of potential environmental effects from produced water in the Sable Island Bank region (NS, Canada) was conducted using an integrated modeling approach according to the ecological risk assessment framework. A hydrodynamic dispersion model was used to describe the wastewater plume. A second fugacity-based model was used to describe the likely plume partitioning in the local environmental media of water, suspended sediment, biota, and sediment. Results from the integrated modeling showed that the soluble benzene and naphthalene components reach chronic no-effect concentration levels at a distance of 1.0 m from the discharge point. The partition modeling indicated that low persistence was expected because of advection forces caused by tidal currents for the Sable Island Bank system. The exposure assessment for the two soluble hydrocarbon components suggests that the risks of adverse environmental effects from produced water on Sable Island Bank are low.

  7. Combining exposure and effect modeling into an integrated probabilistic environmental risk assessment for nanoparticles

    NARCIS (Netherlands)

    Jacobs, Rianne; Meesters, Johannes A.J.; Braak, ter Cajo J.F.; Meent, van de Dik; Voet, van der Hilko

    2016-01-01

    There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To

  8. Combining exposure and effect modeling into an integrated probabilistic environmental risk assessment for nanoparticles

    NARCIS (Netherlands)

    Jacobs, R.; Meesters, J.A.J.; Ter Braak, C.J.; Meent, D. van de; van der Voet, H.

    2016-01-01

    There is a growing need for good environmental risk assessment of engineered nanoparticles (ENPs). Environmental risk assessment of ENPs has been hampered by lack of data and knowledge about ENPs, their environmental fate, and their toxicity. This leads to uncertainty in the risk assessment. To deal

  9. Multiple-Strain Approach and Probabilistic Modeling of Consumer Habits in Quantitative Microbial Risk Assessment: A Quantitative Assessment of Exposure to Staphylococcal Enterotoxin A in Raw Milk.

    Science.gov (United States)

    Crotta, Matteo; Rizzi, Rita; Varisco, Giorgio; Daminelli, Paolo; Cunico, Elena Cosciani; Luini, Mario; Graber, Hans Ulrich; Paterlini, Franco; Guitian, Javier

    2016-03-01

    Quantitative microbial risk assessment (QMRA) models are extensively applied to inform management of a broad range of food safety risks. Inevitably, QMRA modeling involves an element of simplification of the biological process of interest. Two features that are frequently simplified or disregarded are the pathogenicity of multiple strains of a single pathogen and consumer behavior at the household level. In this study, we developed a QMRA model with a multiple-strain approach and a consumer phase module (CPM) based on uncertainty distributions fitted from field data. We modeled exposure to staphylococcal enterotoxin A in raw milk in Lombardy; a specific enterotoxin production module was thus included. The model is adaptable and could be used to assess the risk related to other pathogens in raw milk as well as other staphylococcal enterotoxins. The multiplestrain approach, implemented as a multinomial process, allowed the inclusion of variability and uncertainty with regard to pathogenicity at the bacterial level. Data from 301 questionnaires submitted to raw milk consumers were used to obtain uncertainty distributions for the CPM. The distributions were modeled to be easily updatable with further data or evidence. The sources of uncertainty due to the multiple-strain approach and the CPM were identified, and their impact on the output was assessed by comparing specific scenarios to the baseline. When the distributions reflecting the uncertainty in consumer behavior were fixed to the 95th percentile, the risk of exposure increased up to 160 times. This reflects the importance of taking into consideration the diversity of consumers' habits at the household level and the impact that the lack of knowledge about variables in the CPM can have on the final QMRA estimates. The multiple-strain approach lends itself to use in other food matrices besides raw milk and allows the model to better capture the complexity of the real world and to be capable of geographical

  10. CAirTOX: A compartment model for assessing the fate of and human exposure to toxic-chemical emissions to air

    Energy Technology Data Exchange (ETDEWEB)

    McKone, T.E.

    1993-10-01

    CAirTOX has been developed as a spreadsheet model to assist in making a risk assessment of toxic air emissions. With CAirTOX, one can address how contaminants released to an air basin can lead to contamination of soil, food, surface water, and sediments. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify uncertainty in multimedia, multiple-pathway exposure assessments. The multimedia transport and transformation model is a steady-state, but non-equilibrium model that can be used to assess concentrations of contaminants released continuously to air. In Part 1, the authors describe the multimedia transport and transformation model used to determine the fate of air emissions. In Part 2, they describe inputs and data needs for CAirTOX and the development of a set of landscape factors, which can be used to represent regional air basin/water-shed systems in California. In Part 3, they describe the multiple-pathway exposure scenarios and exposure algorithms. In Part 4, they compare the HRA approach and results and the CAirTOX exposure equations. In Part 5, they consider model sensitivity and uncertainty to determine how variability and uncertainty in model inputs affects the precision, accuracy, and credibility of the model output.

  11. GPS-based Microenvironment Tracker (MicroTrac) Model to Estimate Time-Location of Individuals for Air Pollution Exposure Assessments: Model Evaluation in Central North Carolina

    Science.gov (United States)

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure...

  12. Assessing internal exposure in the absence of an appropriate model: two cases involving an incidental inhalation of transuranic elements

    International Nuclear Information System (INIS)

    Blanchin, N.; Grappin, L.; Guillermin, A.M.; Lafon, P.; Miele, A.; Berard, P.; Blanchardon, E.; Fottorino, R.

    2008-01-01

    Two incidents involving internal exposure by inhalation of transuranic compounds are presented herein. The results of the measurements of urinary and faecal excretions of the two individuals involved do not concur with the values predicted by the ICRP models that should be applied by default, according to the circumstances of the incidents and the chemical form of the products involved: oxide in the first case and nitrate in the second. These cases are remarkable in the similarity of their biokinetic behaviour even though they occurred in different situations and involved different chemical compounds. Both situations provide an illustration of the management of internal contamination events. The precautions to be taken and the questions that the physician should ask himself in the estimation of the internal dose are listed as follows: What type of examinations should be prescribed and at what frequency? What analysis results should be used in assessing the dose? How can the effect of the Ca-DTPA treatment be assessed? How long is it necessary to perform radio toxicological exams before assessing the dose? What should be done if the ICRP model corresponding to the initial circumstances does not fit the measurement data? Finally, our selected hypotheses, used to explain specific biokinetic behaviour and to estimate its intake in both cases, are detailed. These incidental contaminations suggest that further studies should be carried out to develop a new model for inhalation of transuranic compounds that would follow neither the S nor the M absorption type of the respiratory tract model of ICRP publication 66. (authors)

  13. Assessing internal exposure in the absence of an appropriate model: two cases involving an incidental inhalation of transuranic elements

    International Nuclear Information System (INIS)

    Blanchin, Nicolas; Fottorino, Robert; Grappin, Louise; Guillermin, Anne-Marie; Lafon, Philippe; Miele, Alain; Berard, Philippe; Blanchardon, Eric

    2008-01-01

    Two incidents involving internal exposure by inhalation of transuranic compounds are presented herein. The results of the measurements of urinary and faecal excretions of the two individuals involved do not concur with the values predicted by the ICRP models that should be applied by default, according to the circumstances of the incidents and the chemical form of the products involved: oxide in the first case and nitrate in the second. These cases are remarkable in the similarity of their biokinetic behaviour even though they occurred in different situations and involved different chemical compounds. Both situations provide an illustration of the management of internal contamination events. The precautions to be taken and the questions that the physician should ask himself in the estimation of the internal dose are listed as follows: a) What type of examinations should be prescribed and at what frequency?; b) What analysis results should be used in assessing the dose?; c) How can the effect of the Ca-DTPA treatment be assessed?; d) How long is it necessary to perform radio toxicological exams before assessing the dose?; e) What should be done if the ICRP model corresponding to the initial circumstances does not fit the measurement data? Finally, our selected hypotheses, used to explain specific biokinetic behaviour and to estimate its intake in both cases, are detailed. These incidental contaminations suggest that further studies should be carried out to develop a new model for inhalation of transuranic compounds that would follow neither the S nor the M absorption type of the respiratory tract model of ICRP publication 66. (author)

  14. Estimating the value of a Country's built assets: investment-based exposure modelling for global risk assessment

    Science.gov (United States)

    Daniell, James; Pomonis, Antonios; Gunasekera, Rashmin; Ishizawa, Oscar; Gaspari, Maria; Lu, Xijie; Aubrecht, Christoph; Ungar, Joachim

    2017-04-01

    In order to quantify disaster risk, there is a demand and need for determining consistent and reliable economic value of built assets at national or sub national level exposed to natural hazards. The value of the built stock in the context of a city or a country is critical for risk modelling applications as it allows for the upper bound in potential losses to be established. Under the World Bank probabilistic disaster risk assessment - Country Disaster Risk Profiles (CDRP) Program and rapid post-disaster loss analyses in CATDAT, key methodologies have been developed that quantify the asset exposure of a country. In this study, we assess the complementary methods determining value of building stock through capital investment data vs aggregated ground up values based on built area and unit cost of construction analyses. Different approaches to modelling exposure around the world, have resulted in estimated values of built assets of some countries differing by order(s) of magnitude. Using the aforementioned methodology of comparing investment data based capital stock and bottom-up unit cost of construction values per square meter of assets; a suitable range of capital stock estimates for built assets have been created. A blind test format was undertaken to compare the two types of approaches from top-down (investment) and bottom-up (construction cost per unit), In many cases, census data, demographic, engineering and construction cost data are key for bottom-up calculations from previous years. Similarly for the top-down investment approach, distributed GFCF (Gross Fixed Capital Formation) data is also required. Over the past few years, numerous studies have been undertaken through the World Bank Caribbean and Central America disaster risk assessment program adopting this methodology initially developed by Gunasekera et al. (2015). The range of values of the building stock is tested for around 15 countries. In addition, three types of costs - Reconstruction cost

  15. Environmental Health and Aging: Activity, Exposure and Biological Models to Improve Risk Assessment and Health Promotion

    Science.gov (United States)

    The US Environmental Protection Agency (EPA) and other public health agencies are concerned that the environmental health of America’s growing population of older adults has not been taken into consideration in current approaches to risk assessment. The reduced capacity to respo...

  16. Environmental modeling and exposure assessment of sediment-associated pyrethroids in an agricultural watershed.

    Directory of Open Access Journals (Sweden)

    Yuzhou Luo

    Full Text Available Synthetic pyrethroid insecticides have generated public concerns due to their increasing use and potential effects on aquatic ecosystems. A modeling system was developed in this study for simulating the transport processes and associated sediment toxicity of pyrethroids at coupled field/watershed scales. The model was tested in the Orestimba Creek watershed, an agriculturally intensive area in California' Central Valley. Model predictions were satisfactory when compared with measured suspended solid concentration (R(2 = 0.536, pyrethroid toxic unit (0.576, and cumulative mortality of Hyalella azteca (0.570. The results indicated that sediment toxicity in the study area was strongly related to the concentration of pyrethroids in bed sediment. Bifenthrin was identified as the dominant contributor to the sediment toxicity in recent years, accounting for 50-85% of predicted toxicity units. In addition, more than 90% of the variation on the annual maximum toxic unit of pyrethroids was attributed to precipitation and prior application of bifenthrin in the late irrigation season. As one of the first studies simulating the dynamics and spatial variability of pyrethroids in fields and instreams, the modeling results provided useful information on new policies to be considered with respect to pyrethroid regulation. This study suggested two potential measures to efficiently reduce sediment toxicity by pyrethroids in the study area: [1] limiting bifenthrin use immediately before rainfall season; and [2] implementing conservation practices to retain soil on cropland.

  17. GPS-based microenvironment tracker (MicroTrac) model to estimate time-location of individuals for air pollution exposure assessments: model evaluation in central North Carolina.

    Science.gov (United States)

    Breen, Michael S; Long, Thomas C; Schultz, Bradley D; Crooks, James; Breen, Miyuki; Langstaff, John E; Isaacs, Kristin K; Tan, Yu-Mei; Williams, Ronald W; Cao, Ye; Geller, Andrew M; Devlin, Robert B; Batterman, Stuart A; Buckley, Timothy J

    2014-07-01

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure to do so can add uncertainty and bias to risk estimates. In this study, a classification model, called MicroTrac, was developed to estimate time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from global positioning system (GPS) data and geocoded building boundaries. Based on a panel study, MicroTrac estimates were compared with 24-h diary data from nine participants, with corresponding GPS data and building boundaries of home, school, and work. MicroTrac correctly classified the ME for 99.5% of the daily time spent by the participants. The capability of MicroTrac could help to reduce the time-location uncertainty in air pollution exposure models and exposure metrics for individuals in health studies.

  18. GPS-based microenvironment tracker (MicroTrac) model to estimate time–location of individuals for air pollution exposure assessments: Model evaluation in central North Carolina

    Science.gov (United States)

    Breen, Michael S.; Long, Thomas C.; Schultz, Bradley D.; Crooks, James; Breen, Miyuki; Langstaff, John E.; Isaacs, Kristin K.; Tan, Yu-Mei; Williams, Ronald W.; Cao, Ye; Geller, Andrew M.; Devlin, Robert B.; Batterman, Stuart A.; Buckley, Timothy J.

    2014-01-01

    A critical aspect of air pollution exposure assessment is the estimation of the time spent by individuals in various microenvironments (ME). Accounting for the time spent in different ME with different pollutant concentrations can reduce exposure misclassifications, while failure to do so can add uncertainty and bias to risk estimates. In this study, a classification model, called MicroTrac, was developed to estimate time of day and duration spent in eight ME (indoors and outdoors at home, work, school; inside vehicles; other locations) from global positioning system (GPS) data and geocoded building boundaries. Based on a panel study, MicroTrac estimates were compared with 24-h diary data from nine participants, with corresponding GPS data and building boundaries of home, school, and work. MicroTrac correctly classified the ME for 99.5% of the daily time spent by the participants. The capability of MicroTrac could help to reduce the time–location uncertainty in air pollution exposure models and exposure metrics for individuals in health studies. PMID:24619294

  19. Assessment of dermal exposure to chemicals

    NARCIS (Netherlands)

    Hemmen, J.J. van; Brouwer, D.H.

    1995-01-01

    The methods for the dermal exposure assessment vary in their complexity and are in some sense complementary to each other. The most easy-to-use methods involve a pseudo-skin-approach, such as gloves and removal by washing. In some cases generic modelling appears to be possible. The experimental

  20. Safety assessments for potential exposures

    International Nuclear Information System (INIS)

    Dunn, D.I.

    2012-04-01

    Safety Assessment of potential exposures have been carried out in major practices, namely: industrial radiography, gamma irradiators and electron accelerators used in industry and research, and radiotherapy. This paper focuses on reviewing safety assessment methodologies and using developed software to analyse radiological accidents, also review, and discuss these past accidents.The primary objective of the assessment is to assess the adequacy of planned or existing measures for protection and safety and to identify any additional measures that should be put in place. As such, both routine use of the source and the probability and magnitude of potential exposures arising from accidents or incidents should be considered. Where the assessment indicates that there is a realistic possibility of an accident affecting workers or members of the public or having consequences for the environment, the registrant or licensee should prepare a suitable emergency plan. A safety assessment for normal operation addresses all the conditions under which the radiation source operates as expected, including all phases of the lifetime of the source. Due account needs to be taken of the different factors and conditions that will apply during non-operational phases, such as installation, commissioning and maintenance. (author)

  1. Probabilistic calculations and sensitivity analysis of parameters for a reference biosphere model assessing the potential exposure of a population to radionuclides from a deep geological repository

    Energy Technology Data Exchange (ETDEWEB)

    Staudt, Christian; Kaiser, Jan Christian [Helmholtz Zentrum Muenchen, Institute of Radiation Protection, Munich (Germany); Proehl, Gerhard [International Atomic Energy Agency, Division of Radiation, Transport and Waste Safety, Wagramerstrasse 5, 1400 Vienna (Austria)

    2014-07-01

    Radioecological models are used to assess the exposure of hypothetical populations to radionuclides. Potential radionuclide sources are deep geological repositories for high level radioactive waste. Assessment time frames are long since releases from those repositories are only expected in the far future, and radionuclide migration to the geosphere biosphere interface will take additional time. Due to the long time frames, climate conditions at the repository site will change, leading to changing exposure pathways and model parameters. To identify climate dependent changes in exposure in the far field of a deep geological repository a range of reference biosphere models representing climate analogues for potential future climate states at a German site were developed. In this approach, model scenarios are developed for different contemporary climate states. It is assumed that the exposure pathways and parameters of the contemporary biosphere in the far field of the repository will change to be similar to those at the analogue sites. Since current climate models cannot predict climate developments over the assessment time frame of 1 million years, analogues for a range of realistically possible future climate conditions were selected. These climate states range from steppe to permafrost climate. As model endpoint Biosphere Dose conversion factors (BDCF) are calculated. The radionuclide specific BDCF describe the exposure of a population to radionuclides entering the biosphere in near surface ground water. The BDCF are subject to uncertainties in the exposure pathways and model parameters. In the presented work, probabilistic and sensitivity analysis was used to assess the influence of model parameter uncertainties on the BDCF and the relevance of individual parameters for the model result. This was done for the long half-live radionuclides Cs-135, I-129 and U-238. In addition to this, BDCF distributions for nine climate reference regions and several scenarios were

  2. 76 FR 365 - Exposure Modeling Public Meeting

    Science.gov (United States)

    2011-01-04

    ... classification for ecological risk assessments using aerial photography and GIS data. Dermal contact, movement... ENVIRONMENTAL PROTECTION AGENCY [EPA-HQ-OPP-2009-0879; FRL-8860-5] Exposure Modeling Public Meeting AGENCY: Environmental Protection Agency (EPA). ACTION: Notice. SUMMARY: An Exposure Modeling...

  3. Challenges and perspectives of nanoparticle exposure assessment.

    Science.gov (United States)

    Lee, Ji Hyun; Moon, Min Chaul; Lee, Joon Yeob; Yu, Il Je

    2010-06-01

    Nanoparticle exposure assessment presents a unique challenge in the field of occupational and environmental health. With the commercialization of nanotechnology, exposure usually starts from the workplace and then spreads to environment and consumer exposure. This report discusses the current trends of nanoparticle exposure assessment, including the definition of nanotechnology relevant terms, essential physicochemical properties for nanomaterial characterization, current international activities related nanomaterial safety, and exposure assessment standard development for nanotechnology. Further this report describes challenges of nanoparticle exposure assessment such as background measurement, metrics of nanoparticle exposure assessment and personal sampling.

  4. Exposure factors for marine eutrophication impacts assessment based on a mechanistic biological model

    DEFF Research Database (Denmark)

    Cosme, Nuno Miguel Dias; Koski, Marja; Hauschild, Michael Zwicky

    2015-01-01

    marine ecosystem (LME), five climate zones, and site-generic. The XFs obtained range from 0.45 (Central Arctic Ocean) to 15.9kgO2kgN-1 (Baltic Sea). While LME resolution is recommended, aggregated PE or XF per climate zone can be adopted, but not global aggregation due to high variability. The XF......Emissions of nitrogen (N) from anthropogenic sources enrich marine waters and promote planktonic growth. This newly synthesised organic carbon is eventually exported to benthic waters where aerobic respiration by heterotrophic bacteria results in the consumption of dissolved oxygen (DO......). This pathway is typical of marine eutrophication. A model is proposed to mechanistically estimate the response of coastal marine ecosystems to N inputs. It addresses the biological processes of nutrient-limited primary production (PP), metazoan consumption, and bacterial degradation, in four distinct sinking...

  5. Bayesian Algorithm Implementation in a Real Time Exposure Assessment Model on Benzene with Calculation of Associated Cancer Risks

    OpenAIRE

    Sarigiannis, Dimosthenis A.; Karakitsios, Spyros P.; Gotti, Alberto; Papaloukas, Costas L.; Kassomenos, Pavlos A.; Pilidis, Georgios A.

    2009-01-01

    The objective of the current study was the development of a reliable modeling platform to calculate in real time the personal exposure and the associated health risk for filling station employees evaluating current environmental parameters (traffic, meteorological and amount of fuel traded) determined by the appropriate sensor network. A set of Artificial Neural Networks (ANNs) was developed to predict benzene exposure pattern for the filling station employees. Furthermore, a Physiology Based...

  6. Framework for Multi-Pathway Cumulative Exposure for Comparative Assessments

    DEFF Research Database (Denmark)

    McKone, Tom; Fantke, Peter

    2016-01-01

    in comparative risk assessment, life-cycle assessment (LCA), and chemical alternatives assessment (CAA), multimedia fate and exposure models synthesize information about partitioning, reaction, and intermedia-transport properties of chemicals in a representative (local to regional) or generic (continental...

  7. AirPEx. Air Pollution Exposure Model

    Energy Technology Data Exchange (ETDEWEB)

    Freijer, J.I.; Bloemen, H.J.Th.; De Loos, S.; Marra, M.; Rombout, P.J.A.; Steentjes, G.M.; Van Veen, M.P.

    1997-12-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The principal grounds for studying the inhalatory exposure of humans to air pollutants are formed by the need for realistic exposure/dose estimates to evaluate the health effects of these pollutants. The AirPEx (Air Pollution Exposure) model, developed to assess the time- and space-dependence of inhalatory exposure of humans to air pollution, has been implemented for use as a Windows 3.1 computer program. The program is suited to estimating various exposure and dose quantities for individuals, as well as for populations and subpopulations. This report describes the fundamentals of the AirPEx model and provides a user manual for the computer program. Several examples included in the report illustrate the possibilities of the AirPEx model in exposure assessment. The model will be used at the National Institute of Public Health and the Environment as a tool in analysing the current exposure of the Dutch population to air pollutants. 57 refs.

  8. Integrated Environmental Assessment Part III: ExposureAssessment

    Energy Technology Data Exchange (ETDEWEB)

    McKone, Thomas E.; Small, Mitchell J.

    2006-06-01

    Human exposure assessment is a key step in estimating the environmental and public health burdens that result chemical emissions in the life cycle of an industrial product or service. This column presents the third in a series of overviews of the state of the art in integrated environmental assessment - earlier columns described emissions estimation (Frey and Small, 2003) and fate and transport modeling (Ramaswami, et al., 2004). When combined, these first two assessment elements provide estimates of ambient concentrations in the environment. Here we discuss how both models and measurements are used to translate ambient concentrations into metrics of human and ecological exposure, the necessary precursors to impact assessment. Exposure assessment is the process of measuring and/or modeling the magnitude, frequency and duration of contact between a potentially harmful agent and a target population, including the size and characteristics of that population (IPCS, 2001; Zartarian, et al., 2005). Ideally the exposure assessment process should characterize the sources, routes, pathways, and uncertainties in the assessment. Route of exposure refers to the way that an agent enters the receptor during an exposure event. Humans contact pollutants through three routes--inhalation, ingestion, and dermal uptake. Inhalation occurs in both outdoor environments and indoor environments where most people spend the majority of their time. Ingestion includes both water and food, as well as soil and dust uptake due to hand-to-mouth activity. Dermal uptake occurs through contacts with consumer products; indoor and outdoor surfaces; the water supply during washing or bathing; ambient surface waters during swimming or boating; soil during activities such as work, gardening, and play; and, to a lesser extent, from the air that surrounds us. An exposure pathway is the course that a pollutant takes from an ambient environmental medium (air, soil, water, biota, etc), to an exposure medium

  9. Are engineered nano iron oxide particles safe? an environmental risk assessment by probabilistic exposure, effects and risk modeling.

    Science.gov (United States)

    Wang, Yan; Deng, Lei; Caballero-Guzman, Alejandro; Nowack, Bernd

    2016-12-01

    Nano iron oxide particles are beneficial to our daily lives through their use in paints, construction materials, biomedical imaging and other industrial fields. However, little is known about the possible risks associated with the current exposure level of engineered nano iron oxides (nano-FeOX) to organisms in the environment. The goal of this study was to predict the release of nano-FeOX to the environment and assess their risks for surface waters in the EU and Switzerland. The material flows of nano-FeOX to technical compartments (waste incineration and waste water treatment plants) and to the environment were calculated with a probabilistic modeling approach. The mean value of the predicted environmental concentrations (PECs) of nano-FeOX in surface waters in the EU for a worst-case scenario (no particle sedimentation) was estimated to be 28 ng/l. Using a probabilistic species sensitivity distribution, the predicted no-effect concentration (PNEC) was determined from ecotoxicological data. The risk characterization ratio, calculated by dividing the PEC by PNEC values, was used to characterize the risks. The mean risk characterization ratio was predicted to be several orders of magnitude smaller than 1 (1.4 × 10 - 4 ). Therefore, this modeling effort indicates that only a very limited risk is posed by the current release level of nano-FeOX to organisms in surface waters. However, a better understanding of the hazards of nano-FeOX to the organisms in other ecosystems (such as sediment) needs to be assessed to determine the overall risk of these particles to the environment.

  10. Challenges and Perspectives of Nanoparticle Exposure Assessment

    OpenAIRE

    Lee, Ji Hyun; Moon, Min Chaul; Lee, Joon Yeob; Yu, Il Je

    2010-01-01

    Nanoparticle exposure assessment presents a unique challenge in the field of occupational and environmental health. With the commercialization of nanotechnology, exposure usually starts from the workplace and then spreads to environment and consumer exposure. This report discusses the current trends of nanoparticle exposure assessment, including the definition of nanotechnology relevant terms, essential physicochemical properties for nanomaterial characterization, current international activi...

  11. Chapter three: methodology of exposure modeling

    CSIR Research Space (South Africa)

    Moschandreas, DJ

    2002-12-01

    Full Text Available methodologies and models are reviewed. Three exposure/measurement methodologies are assessed. Estimation methods focus on source evaluation and attribution, sources include those outdoors and indoors as well as in occupational and in-transit environments. Fate...

  12. Assessment of inhomogeneous ELF magnetic field exposures

    International Nuclear Information System (INIS)

    Leitgeb, N.; Cech, R.; Schroettner, J.

    2008-01-01

    In daily life as well as at workplaces, exposures to inhomogeneous magnetic fields become very frequent. This makes easily applicable compliance assessment methods increasingly important. Reference levels have been defined linking basic restrictions to levels of homogeneous fields at worst-case exposure conditions. If reference levels are met, compliance with basic restrictions can be assumed. If not, further investigations could still prove compliance. Because of the lower induction efficiency, inhomogeneous magnetic fields such as from electric appliances could be allowed exceeding reference levels. To easily assess inhomogeneous magnetic fields, a quick and flexible multi-step assessment procedure is proposed. On the basis of simulations with numerical, anatomical human models reference factors were calculated elevating reference levels to link hot-spot values measured at source surfaces to basic limits and allowing accounting for different source distance, size, orientation and position. Compliance rules are proposed minimising assessment efforts. (authors)

  13. An Exposure Assessment of Polybrominated Diphenyl Ethers ...

    Science.gov (United States)

    EPA announced the availability of the final report, An Exposure Assessment of Polybrominated Diphenyl Ethers. This report provides a comprehensive assessment of the exposure of Americans to this class of persistent organic pollutants. Individual chapters in this document address: the production, use, and lifecycle of PBDEs; environmental fate; environmental levels; and human exposure. This final report addresses the exposure assessment needs identified in the OPBDE Workgroup project plan. It provides a comprehensive assessment of the exposure of Americans to this class of persistent organic pollutants. Individual chapters in this document address: the production, use, and lifecycle of PBDEs; environmental fate; environmental levels; and human exposure.

  14. Making fate and exposure models for freshwater ecotoxicity in life cycle assessment suitable for organic acids and bases.

    Science.gov (United States)

    van Zelm, Rosalie; Stam, Gea; Huijbregts, Mark A J; van de Meent, Dik

    2013-01-01

    Freshwater fate and exposure factors were determined for organic acids and bases, making use of the knowledge on electrical interaction of ionizing chemicals and their sorption to particles. The fate factor represents the residence time in the environment whereas exposure factors equal the dissolved fraction of a chemical. Multimedia fate, exposure, and effect model USES-LCA was updated to take into account the influence of ionization, based upon the acid dissociation constant (pK(a)) of a chemical, and the environmental pH. Freshwater fate (FF) and exposure (XF) factors were determined for 415 acids and 496 bases emitted to freshwater, air, and soil. The relevance of taking account of the degree of ionization of chemicals was tested by determining the ratio (R) of the new vs. fate and exposure factors determined with USES-LCA suitable for neutral chemicals only. Our results show that the majority of freshwater fate and exposure factors of chemicals that are largely ionized in the environment are larger with the ionics model compared to the factors determined with the neutrals model version. R(FF) ranged from 2.4×10(-1) to 1.6×10(1) for freshwater emissions, from 1.2×10(-2) to 2.0×10(4) for soil emissions and from 5.8×10(-2) to 6.0×10(3) for air emissions, and R(XF) from 5.3×10(-1) to 2.2×10(1). Prediction of changed solid-water partitioning, implying a change in runoff and in removal via sedimentation, and prediction of negligible air-water partition coefficient, leading to negligible volatilization were the main contributors to the changes in freshwater fate factors. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Statistical multi-path exposure method for assessing the whole-body SAR in a heterogeneous human body model in a realistic environment.

    Science.gov (United States)

    Vermeeren, Günter; Joseph, Wout; Martens, Luc

    2013-04-01

    Assessing the whole-body absorption in a human in a realistic environment requires a statistical approach covering all possible exposure situations. This article describes the development of a statistical multi-path exposure method for heterogeneous realistic human body models. The method is applied for the 6-year-old Virtual Family boy (VFB) exposed to the GSM downlink at 950 MHz. It is shown that the whole-body SAR does not differ significantly over the different environments at an operating frequency of 950 MHz. Furthermore, the whole-body SAR in the VFB for multi-path exposure exceeds the whole-body SAR for worst-case single-incident plane wave exposure by 3.6%. Moreover, the ICNIRP reference levels are not conservative with the basic restrictions in 0.3% of the exposure samples for the VFB at the GSM downlink of 950 MHz. The homogeneous spheroid with the dielectric properties of the head suggested by the IEC underestimates the absorption compared to realistic human body models. Moreover, the variation in the whole-body SAR for realistic human body models is larger than for homogeneous spheroid models. This is mainly due to the heterogeneity of the tissues and the irregular shape of the realistic human body model compared to homogeneous spheroid human body models. Copyright © 2012 Wiley Periodicals, Inc.

  16. The assessment of the aircrew exposure

    International Nuclear Information System (INIS)

    Tommasino, L.

    2002-01-01

    In 1991 ICRP first included exposure of aircraft crew to cosmic radiation as occupational exposure. The European Dosimetry Group (EURADOS) established a working group in 1992 to address this issue. The report 'Exposure of Air Crew to Cosmic Radiation' was published in the European Commission's Radiation Protection series as report 85. The first section of the report assesses the existing data on radiation exposure, describes the radiation environment at civil aviation altitudes and summarizes the computational models that have been developed to describe the cosmic ray radiation field in the atmosphere. The second section describes the quantities used to assess the radiation doses. It is clear that conventional radiation protection dosimetry as applied on the ground is not quite applicable to the situation for air crews. A multinational European research project was launched to investigate the problem of cosmic rays and dosimetry at aviation altitudes. The major objective was to measure the flux and energy spectra of neutrons and charged particles over a wide energy interval at aviation altitudes and compare the results with those calculated with various computer codes. Within the project much progress was made in different areas, for instance the determination of the fundamental physical characteristics of the cosmic radiation field at aircraft altitudes, development of instrumentation, measurements of dose rates and route doses and application of routine radiation protection. Surveys of air crew exposure have been carried out with different advanced dosimetric systems and comparisons were made between passive and real-time detector systems

  17. Review of the chronic exposure pathways models in MACCS [MELCOR Accident Consequence Code System] and several other well-known probabilistic risk assessment models

    International Nuclear Information System (INIS)

    Tveten, U.

    1990-06-01

    The purpose of this report is to document the results of the work performed by the author in connection with the following task, performed for US Nuclear Regulatory Commission, (USNRC) Office of Nuclear Regulatory Research, Division of Systems Research: MACCS Chronic Exposure Pathway Models: Review the chronic exposure pathway models implemented in the MELCOR Accident Consequence Code System (MACCS) and compare those models to the chronic exposure pathway models implemented in similar codes developed in countries that are members of the OECD. The chronic exposures concerned are via: the terrestrial food pathways, the water pathways, the long-term groundshine pathway, and the inhalation of resuspended radionuclides pathway. The USNRC has indicated during discussions of the task that the major effort should be spent on the terrestrial food pathways. There is one chapter for each of the categories of chronic exposure pathways listed above

  18. Exposure Assessment Tools by Chemical Classes - Nanomaterials

    Science.gov (United States)

    EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

  19. Development of a dynamic model for the assessment of environmental radiation exposures through the stagnant water pathway

    International Nuclear Information System (INIS)

    Saenger, W.; Huebel, K.

    1991-01-01

    The model describes time-dependent changes in activity concentrations that 5 ecological variables (water, tripton, plankton, sediment, fishes) undergo in stagnant waters after brief exposure to high radioactive loads. The evaluation of Chernobyl data within the context of this model leads to meaningful results, if one describes the radionuclide migration as being faster than all subsequent activity changes - preferably as the so-called delta function. The model comprises a system of 5 coupled, analytically approachable rate balances in the form of 5 time-dependent first degree differential equations with constant coefficients. The latter are determined by adjusting the analytical solutions for the model system (model functions) to the values measured. (orig./HP) [de

  20. Health risk assessment of exposure to ionizing radiation

    International Nuclear Information System (INIS)

    Ogata, Hiromitsu

    2011-01-01

    Risk assessment is an essential process for evaluating the human health effects of exposure to ionizing radiation and for determining acceptable levels of exposure. There are two major components of radiation risk assessment: a measure of exposure level and a measure of disease occurrence. For quantitative estimation of health risks, it is important to evaluate the association between exposure and disease occurrence using epidemiological or experimental data. In these approaches, statistical risk models are used particularly for estimating cancer risks related to exposure to low levels of radiation. This paper presents a summary of basic models and methods of risk assessment for studying exposure-risk relationships. Moreover, quantitative risk estimates are subject to several sources of uncertainty due to inherent limitations in risk assessment studies. This paper also discusses the limitations of radiation risk assessment. (author)

  1. Assessing vanadium and arsenic exposure of people living near a petrochemical complex with two-stage dispersion models

    International Nuclear Information System (INIS)

    Chio, Chia-Pin; Yuan, Tzu-Hsuen; Shie, Ruei-Hao; Chan, Chang-Chuan

    2014-01-01

    Highlights: • Two-stage dispersion models can estimate exposures to hazardous air pollutants. • Spatial distribution of V levels is derived for sources without known emission rates. • A distance-to-source gradient is found for V levels from a petrochemical complex. • Two-stage dispersion is useful for modeling air pollution in resource-limited areas. - Abstract: The goal of this study is to demonstrate that it is possible to construct a two-stage dispersion model empirically for the purpose of estimating air pollution levels in the vicinity of petrochemical plants. We studied oil refineries and coal-fired power plants in the No. 6 Naphtha Cracking Complex, an area of 2,603-ha situated on the central west coast of Taiwan. The pollutants targeted were vanadium (V) from oil refineries and arsenic (As) from coal-fired power plants. We applied a backward fitting method to determine emission rates of V and As, with 192 PM 10 filters originally collected between 2009 and 2012. Our first-stage model estimated emission rates of V and As (median and 95% confidence intervals at 0.0202 (0.0040–0.1063) and 0.1368 (0.0398–0.4782) g/s, respectively. In our second stage model, the predicted zone-average concentrations showed a strong correlation with V, but a poor correlation with As. Our findings show that two-stage dispersion models are relatively precise for estimating V levels at residents’ addresses near the petrochemical complex, but they did not work as well for As levels. In conclusion, our model-based approach can be widely used for modeling exposure to air pollution from industrial areas in countries with limited resources

  2. Probabilistic assessment of wildfire hazard and municipal watershed exposure

    Science.gov (United States)

    Joe Scott; Don Helmbrecht; Matthew P. Thompson; David E. Calkin; Kate Marcille

    2012-01-01

    The occurrence of wildfires within municipal watersheds can result in significant impacts to water quality and ultimately human health and safety. In this paper, we illustrate the application of geospatial analysis and burn probability modeling to assess the exposure of municipal watersheds to wildfire. Our assessment of wildfire exposure consists of two primary...

  3. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

    Science.gov (United States)

    Denkins, Pamela; Badhwar, Gautam; Obot, Victor; Wilson, Bobby; Jejelewo, Olufisayo

    2001-08-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far, the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space, exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

  4. Radiation transport modeling and assessment to better predict radiation exposure, dose, and toxicological effects to human organs on long duration space flights

    Science.gov (United States)

    Denkins, P.; Badhwar, G.; Obot, V.; Wilson, B.; Jejelewo, O.

    2001-01-01

    NASA is very interested in improving its ability to monitor and forecast the radiation levels that pose a health risk to space-walking astronauts as they construct the International Space Station and astronauts that will participate in long-term and deep-space missions. Human exploratory missions to the moon and Mars within the next quarter century, will expose crews to transient radiation from solar particle events which include high-energy galactic cosmic rays and high-energy protons. Because the radiation levels in space are high and solar activity is presently unpredictable, adequate shielding is needed to minimize the deleterious health effects of exposure to radiation. Today, numerous models have been developed and used to predict radiation exposure. Such a model is the Space Environment Information Systems (SPENVIS) modeling program, developed by the Belgian Institute for Space Aeronautics. SPENVIS, which has been assessed to be an excellent tool in characterizing the radiation environment for microelectronics and investigating orbital debris, is being evaluated for its usefulness with determining the dose and dose-equivalent for human exposure. Thus far. the calculations for dose-depth relations under varying shielding conditions have been in agreement with calculations done using HZETRN and PDOSE, which are well-known and widely used models for characterizing the environments for human exploratory missions. There is disagreement when assessing the impact of secondary radiation particles since SPENVIS does a crude estimation of the secondary radiation particles when calculating LET versus Flux. SPENVIS was used to model dose-depth relations for the blood-forming organs. Radiation sickness and cancer are life-threatening consequences resulting from radiation exposure. In space. exposure to radiation generally includes all of the critical organs. Biological and toxicological impacts have been included for discussion along with alternative risk mitigation

  5. Comparative Plasma Exposure and Lung Distribution of Two Human Use Commercial Azithromycin Formulations Assessed in Murine Model: A Preclinical Study

    OpenAIRE

    Rivulgo, Virginia Margarita; Sparo, Mónica; Ceci, Mónica; Fumuso, Elida; Confalonieri, Alejandra; Delpech, Gastón; Sanchez Bruni, Sergio Fabian

    2016-01-01

    Azithromycin(AZM)therapeutic failure and relapses of patients treated with generic -35 formulations have been observed in clinical practice.The main goal of this research was 36 to compare in a pre-clinical study the serum exposure and lung tissue concentrationof 37 two commercial formulations AZM-based in murine model. The current study involved 38 264 healthy Balb-C.Mice were divided in two groups (n=44): Animals of Group A 39 (Reference Formulation ?R-) were orally treated with AZM suspens...

  6. Modeled population exposures to ozone

    Data.gov (United States)

    U.S. Environmental Protection Agency — Population exposures to ozone from APEX modeling for combinations of potential future air quality and demographic change scenarios. This dataset is not publicly...

  7. Evaluation and Quantification of Uncertainty in the Modeling of Contaminant Transport and Exposure Assessment at a Radioactive Waste Disposal Site

    Science.gov (United States)

    Tauxe, J.; Black, P.; Carilli, J.; Catlett, K.; Crowe, B.; Hooten, M.; Rawlinson, S.; Schuh, A.; Stockton, T.; Yucel, V.

    2002-12-01

    The disposal of low-level radioactive waste (LLW) in the United States (U.S.) is a highly regulated undertaking. The U.S. Department of Energy (DOE), itself a large generator of such wastes, requires a substantial amount of analysis and assessment before permitting disposal of LLW at its facilities. One of the requirements that must be met in assessing the performance of a disposal site and technology is that a Performance Assessment (PA) demonstrate "reasonable expectation" that certain performance objectives, such as dose to a hypothetical future receptor, not be exceeded. The phrase "reasonable expectation" implies recognition of uncertainty in the assessment process. In order for this uncertainty to be quantified and communicated to decision makers, the PA computer model must accept probabilistic (uncertain) input (parameter values) and produce results which reflect that uncertainty as it is propagated through the model calculations. The GoldSim modeling software was selected for the task due to its unique facility with both probabilistic analysis and radioactive contaminant transport. Probabilistic model parameters range from water content and other physical properties of alluvium to the activity of radionuclides disposed to the amount of time a future resident might be expected to spend tending a garden. Although these parameters govern processes which are defined in isolation as rather simple differential equations, the complex interaction of couple processes makes for a highly nonlinear system with often unanticipated results. The decision maker has the difficult job of evaluating the uncertainty of modeling results in the context of granting permission for LLW disposal. This job also involves the evaluation of alternatives, such as the selection of disposal technologies. Various scenarios can be evaluated in the model, so that the effects of, for example, using a thicker soil cap over the waste cell can be assessed. This ability to evaluate mitigation

  8. Models for Pesticide Risk Assessment

    Science.gov (United States)

    EPA considers the toxicity of the pesticide as well as the amount of pesticide to which a person or the environments may be exposed in risk assessment. Scientists use mathematical models to predict pesticide concentrations in exposure assessment.

  9. Advances in real-time technology assessment and emergency response: Close-in atmospheric dispersion modeling and exposure estimation

    International Nuclear Information System (INIS)

    Sims, J.; Lee, R.; McCallen, R.; Lawver, B.; Clark, J.; Rueppel, D.; Sullivan, T.

    1992-07-01

    We have developed a stand-alone, real-time emergency response system to assess and predict the offsite dispersion of particulate releases. We have also developed advanced modeling tools that win expand the capability of the emergency response system to predict nearfield dispersion over complex terrain and around buildings

  10. Assessment of Human Exposure to ENMs.

    Science.gov (United States)

    Jiménez, Araceli Sánchez; van Tongeren, Martie

    2017-01-01

    Human exposure assessment of engineered nanomaterials (ENMs) is hampered, among other factors, by the difficulty to differentiate ENM from other nanomaterials (incidental to processes or naturally occurring) and the lack of a single metric that can be used for health risk assessment. It is important that the exposure assessment is carried out throughout the entire life-cycle as releases can occur at the different stages of the product life-cycle, from the synthesis, manufacture of the nano-enable product (occupational exposure) to the professional and consumer use of nano-enabled product (consumer exposure) and at the end of life.Occupational exposure surveys should follow a tiered approach, increasing in complexity in terms of instruments used and sampling strategy applied with higher tiers in order tailor the exposure assessment to the specific materials used and workplace exposure scenarios and to reduce uncertainty in assessment of exposure. Assessment of consumer exposure and of releases from end-of-life processes currently relies on release testing of nano-enabled products in laboratory settings.

  11. Assessing the Cytotoxicity of Black Carbon As A Model for Ultrafine Anthropogenic Aerosol Across Human and Murine Cells: A Chronic Exposure Model of Nanosized Particulate Matter

    Science.gov (United States)

    Salinas, E.

    2015-12-01

    Combustion-derived nanomaterials or ultrafine (fuels. Ultrafine particles (UFPs) can absorb other noxious pollutants including volatile organic compounds (VOCs), polycyclic aromatic hydrocarbons (PAHs), toxic organic compounds, and heavy metals. The combination of high population density, meteorological conditions, and industrial productivity brings high levels of air pollution to the metropolitan area of El Paso, Texas, USA/ Ciudad Juarez, Chihuahua, Mexico, comprising the Paso del Norte air basin. A study conducted by scientists from the Research Triangle Park in North Carolina, analyzed sites adjacent to heavy-traffic highways in El Paso and elucidated higher UFP concentrations in comparison to previously published work exploring pollution and adverse health effects in the basin. UFPs can penetrate deep into the alveolar sacs of the lung, reaching distant alveolar sacs and inducing a series of immune responses that are detrimental to the body: evidence suggests that UFPs can also cross the alveolar-blood barrier and potentially endanger the body's immune response. The physical properties of UFPs and the dynamics of local atmospheric and topographical conditions indicate that emissions of nanosized carbonaceous aerosols could pose significant threats to biological tissues upon inhalation by local residents of the Paso del Norte. This study utilizes Black Carbon (BC) as a model for environmental UFPs and its effects on the immunological response. An in vitro approach is used to measure the ability of BC to promote cell death upon long-term exposure. Human epithelial lung cells (A549), human peripheral-blood monocytes (THP-1), murine macrophages (RAW264.7), and murine epithelial lung cells (LA-4) were treated with BC and assessed for metabolic activity after chronic exposure utilizing three distinct and independent cell viability assays. The cell viability experiments included a chronic study at 7, 10, and 14 days of UFP exposure at six different concentrations of

  12. Respiratory hazard assessment of combined exposure to complete gasoline exhaust and respirable volcanic ash in a multicellular human lung model at the air-liquid interface

    Science.gov (United States)

    Tomasek, Ines; Horwell, Claire J.; Bisig, Christoph; Damby, David; Comte, Pierre; Czerwinski, Jan; Petri-Fink, Alke; Clift, Martin J D; Drasler, Barbara; Rothen-Rutishauer, Barbara

    2018-01-01

    Communities resident in urban areas located near active volcanoes can experience volcanic ash exposures during, and following, an eruption, in addition to sustained exposures to high concentrations of anthropogenic air pollutants (e.g., vehicle exhaust emissions). Inhalation of anthropogenic pollution is known to cause the onset of, or exacerbate, respiratory and cardiovascular diseases. It is further postulated similar exposure to volcanic ash can also affect such disease states. Understanding of the impact of combined exposure of volcanic ash and anthropogenic pollution to human health, however, remains limited.The aim of this study was to assess the biological impact of combined exposure to respirable volcanic ash (from Soufrière Hills volcano (SHV), Montserrat and Chaitén volcano (ChV), Chile; representing different magmatic compositions and eruption styles) and freshly-generated complete exhaust from a gasoline vehicle. A multicellular human lung model (an epithelial cell-layer composed of A549 alveolar type II-like cells complemented with human blood monocyte-derived macrophages and dendritic cells cultured at the air-liquid interface) was exposed to diluted exhaust (1:10) continuously for 6 h, followed by immediate exposure to the ash as a dry powder (0.54 ± 0.19 μg/cm2 and 0.39 ± 0.09 μg/cm2 for SHV and ChV ash, respectively). After an 18 h incubation, cells were exposed again for 6 h to diluted exhaust, and a final 18 h incubation (at 37 °C and 5% CO2). Cell cultures were then assessed for cytotoxic, oxidative stress and (pro-)inflammatory responses.Results indicate that, at all tested (sub-lethal) concentrations, co-exposures with both ash samples induced no significant expression of genes associated with oxidative stress (HMOX1, NQO1) or production of (pro-)inflammatory markers (IL-1β, IL-8, TNF-α) at the gene and protein levels. In summary, considering the employed experimental conditions, combined exposure of

  13. Respiratory hazard assessment of combined exposure to complete gasoline exhaust and respirable volcanic ash in a multicellular human lung model at the air-liquid interface.

    Science.gov (United States)

    Tomašek, Ines; Horwell, Claire J; Bisig, Christoph; Damby, David E; Comte, Pierre; Czerwinski, Jan; Petri-Fink, Alke; Clift, Martin J D; Drasler, Barbara; Rothen-Rutishauser, Barbara

    2018-07-01

    Communities resident in urban areas located near active volcanoes can experience volcanic ash exposures during, and following, an eruption, in addition to sustained exposures to high concentrations of anthropogenic air pollutants (e.g., vehicle exhaust emissions). Inhalation of anthropogenic pollution is known to cause the onset of, or exacerbate, respiratory and cardiovascular diseases. It is further postulated similar exposure to volcanic ash can also affect such disease states. Understanding of the impact of combined exposure of volcanic ash and anthropogenic pollution to human health, however, remains limited. The aim of this study was to assess the biological impact of combined exposure to respirable volcanic ash (from Soufrière Hills volcano (SHV), Montserrat and Chaitén volcano (ChV), Chile; representing different magmatic compositions and eruption styles) and freshly-generated complete exhaust from a gasoline vehicle. A multicellular human lung model (an epithelial cell-layer composed of A549 alveolar type II-like cells complemented with human blood monocyte-derived macrophages and dendritic cells cultured at the air-liquid interface) was exposed to diluted exhaust (1:10) continuously for 6 h, followed by immediate exposure to the ash as a dry powder (0.54 ± 0.19 μg/cm 2 and 0.39 ± 0.09 μg/cm 2 for SHV and ChV ash, respectively). After an 18 h incubation, cells were exposed again for 6 h to diluted exhaust, and a final 18 h incubation (at 37 °C and 5% CO 2 ). Cell cultures were then assessed for cytotoxic, oxidative stress and (pro-)inflammatory responses. Results indicate that, at all tested (sub-lethal) concentrations, co-exposures with both ash samples induced no significant expression of genes associated with oxidative stress (HMOX1, NQO1) or production of (pro-)inflammatory markers (IL-1β, IL-8, TNF-α) at the gene and protein levels. In summary, considering the employed experimental conditions, combined exposure of

  14. Assessing population exposures to motor vehicle exhaust.

    Science.gov (United States)

    Van Atten, Chris; Brauer, Michael; Funk, Tami; Gilbert, Nicolas L; Graham, Lisa; Kaden, Debra; Miller, Paul J; Bracho, Leonora Rojas; Wheeler, Amanda; White, Ronald H

    2005-01-01

    The need is growing for a better assessment of population exposures to motor vehicle exhaust in proximity to major roads and highways. This need is driven in part by emerging scientific evidence of adverse health effects from such exposures and policy requirements for a more targeted assessment of localized public health impacts related to road expansions and increasing commercial transportation. The momentum for improved methods in measuring local exposures is also growing in the scientific community, as well as for discerning which constituents of the vehicle exhaust mixture may exert greater public health risks for those who are exposed to a disproportionate share of roadway pollution. To help elucidate the current state-of-the-science in exposure assessments along major roadways and to help inform decision makers of research needs and trends, we provide an overview of the emerging policy requirements, along with a conceptual framework for assessing exposure to motor-vehicle exhaust that can help inform policy decisions. The framework includes the pathway from the emission of a single vehicle, traffic emissions from multiple vehicles, atmospheric transformation of emissions and interaction with topographic and meteorologic features, and contact with humans resulting in exposure that can result in adverse health impacts. We describe the individual elements within the conceptual framework for exposure assessment and discuss the strengths and weaknesses of various approaches that have been used to assess public exposures to motor vehicle exhaust.

  15. Biodegradation kinetics for pesticide exposure assessment.

    Science.gov (United States)

    Wolt, J D; Nelson, H P; Cleveland, C B; van Wesenbeeck, I J

    2001-01-01

    Understanding pesticide risks requires characterizing pesticide exposure within the environment in a manner that can be broadly generalized across widely varied conditions of use. The coupled processes of sorption and soil degradation are especially important for understanding the potential environmental exposure of pesticides. The data obtained from degradation studies are inherently variable and, when limited in extent, lend uncertainty to exposure characterization and risk assessment. Pesticide decline in soils reflects dynamically coupled processes of sorption and degradation that add complexity to the treatment of soil biodegradation data from a kinetic perspective. Additional complexity arises from study design limitations that may not fully account for the decline in microbial activity of test systems, or that may be inadequate for considerations of all potential dissipation routes for a given pesticide. Accordingly, kinetic treatment of data must accommodate a variety of differing approaches starting with very simple assumptions as to reaction dynamics and extending to more involved treatments if warranted by the available experimental data. Selection of the appropriate kinetic model to describe pesticide degradation should rely on statistical evaluation of the data fit to ensure that the models used are not overparameterized. Recognizing the effects of experimental conditions and methods for kinetic treatment of degradation data is critical for making appropriate comparisons among pesticide biodegradation data sets. Assessment of variability in soil half-life among soils is uncertain because for many pesticides the data on soil degradation rate are limited to one or two soils. Reasonable upper-bound estimates of soil half-life are necessary in risk assessment so that estimated environmental concentrations can be developed from exposure models. Thus, an understanding of the variable and uncertain distribution of soil half-lives in the environment is

  16. Risk assessment and management of radiofrequency radiation exposure

    Energy Technology Data Exchange (ETDEWEB)

    Dabala, Dana [Railways Medical Clinic Cluj-Napoca, Occupational Medicine Department, 16-20 Bilascu Gheorghe St., 400015 Cluj-Napoca (Romania); Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath St., 400293 Cluj-Napoca (Romania)

    2013-11-13

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management.

  17. Risk assessment and management of radiofrequency radiation exposure

    International Nuclear Information System (INIS)

    Dabala, Dana; Surducan, Emanoil; Surducan, Vasile; Neamtu, Camelia

    2013-01-01

    Radiofrequency radiation (RFR) industry managers, occupational physicians, security department, and other practitioners must be advised on the basic of biophysics and the health effects of RF electromagnetic fields so as to guide the management of exposure. Information on biophysics of RFR and biological/heath effects is derived from standard texts, literature and clinical experiences. Emergency treatment and ongoing care is outlined, with clinical approach integrating the circumstances of exposure and the patient's symptoms. Experimental risk assessment model in RFR chronic exposure is proposed. Planning for assessment and monitoring exposure, ongoing care, safety measures and work protection are outlining the proper management

  18. Improvement, Verification, and Refinement of Spatially-Explicit Exposure Models in Risk Assessment - FishRand Spatially-Explicit Bioaccumulation Model Demonstration

    Science.gov (United States)

    2015-08-01

    Unaccounted dynamic habitats and resultant changes in wildlife usage;  Simplified foraging strategies (lacking important considerations such as...and water exposures, fish foraging strategies, and PCB uptake. Figure 2 additionally shows the comparison of standard deviations across the...area (1, 2, and 5) at the Tyndall AFB site. ....................................... 22  Figure 5. Comparison of model predictions to site data for

  19. Presenting of a material exposure health risk assessment model in Oil and Gas Industries (case study: Pars Economic and Energy Region

    Directory of Open Access Journals (Sweden)

    M. Heydari

    2014-02-01

    Result and Conclusion: The results revealed that the quantitative amount of consequence, probability and exposure was 83.2, 8.45, and 2.2, respectively. Generally, the chemical exposure risk number was 1546 which shows that reforming plans are in highly priorities from an economical point of view. William-fine method has the benefit of an accurate chemical exposure by combination of effect severity, exposure probability and detriment rate, and also minimization of personal judgments during the assessment.

  20. Assessing the risk of Legionnaires' disease: the inhalation exposure model and the estimated risk in residential bathrooms.

    Science.gov (United States)

    Azuma, Kenichi; Uchiyama, Iwao; Okumura, Jiro

    2013-02-01

    Legionella are widely found in the built environment. Patients with Legionnaires' disease have been increasing in Japan; however, health risks from Legionella bacteria in the environment are not appropriately assessed. We performed a quantitative health risk assessment modeled on residential bathrooms in the Adachi outbreak area and estimated risk levels. The estimated risks in the Adachi outbreak approximately corresponded to the risk levels exponentially extrapolated into lower levels on the basis of infection and mortality rates calculated from actual outbreaks, suggesting that the model of Legionnaires' disease in residential bathrooms was adequate to predict disease risk for the evaluated outbreaks. Based on this model, the infection and mortality risk levels per year in 10 CFU/100 ml (100 CFU/L) of the Japanese water quality guideline value were approximately 10(-2) and 10(-5), respectively. However, acceptable risk levels of infection and mortality from Legionnaires' disease should be adjusted to approximately 10(-4) and 10(-7), respectively, per year. Therefore, a reference value of 0.1 CFU/100 ml (1 CFU/L) as a water quality guideline for Legionella bacteria is recommended. This value is occasionally less than the actual detection limit. Legionella levels in water system should be maintained as low as reasonably achievable (<1 CFU/L). Copyright © 2012 Elsevier Inc. All rights reserved.

  1. Assessment of risk of potential exposures on facilities industries

    International Nuclear Information System (INIS)

    Leocadio, Joao Carlos

    2007-03-01

    This work develops a model to evaluate potential exposures on open facilities of industrial radiography in Brazil. This model will decisively contribute to optimize operational, radiological protection and safety procedures, to prevent radiation accidents and to reduce human errors in industrial radiography. The probabilistic safety assessment (PSA) methodology was very useful to assess potential exposures. The open facilities of industrial radiography were identified as the scenario to be analyzed in what concerns the evaluation of potential exposures, due to their high accidents indices. The results of the assessment of potential exposures confirm that the industrial radiography in Brazil is a high-risk practice as classified by the IAEA. The risk of potential exposure was estimated to be 40,5 x 10 -2 per year in Brazil, having as main consequences injuries to the workers' hands and arms. In the world scene, the consequences are worst, leading to fatalities of people, thus emphasizing the high risk of industrial radiography. (author)

  2. Lung cancer risk assessment due to traffic-generated particles exposure in urban street canyons: A numerical modelling approach.

    Science.gov (United States)

    Scungio, M; Stabile, L; Rizza, V; Pacitto, A; Russi, A; Buonanno, G

    2018-08-01

    Combustion-generated nanoparticles are responsible for negative health effects due to their ability to penetrate in the lungs, carrying toxic compounds with them. In urban areas, the coexistence of nanoparticle sources and particular street-building configurations can lead to very high particle exposure levels. In the present paper, an innovative approach for the evaluation of lung cancer incidence in street canyon due to exposure to traffic-generated particles was proposed. To this end, the literature-available values of particulate matter, PAHs and heavy metals emitted from different kind of vehicles were used to calculate the Excess Lifetime Cancer Risk (ELCR) at the tailpipe. The estimated ELCR was then used as input data in a numerical CFD (Computational Fluid Dynamics) model that solves the mass, momentum, turbulence and species transport equations, in order to evaluate the cancer risk in every point of interest inside the street canyon. Thus, the influence of wind speed and street canyon geometry (H/W, height of building, H and width of the street, W) on the ELCR at street level was evaluated by means of a CFD simulation. It was found that the ELCR calculated on the leeward and windward sides of the street canyon at a breathable height of 1.5 m, for people exposed 15 min per day for 20 years, is equal to 1.5 × 10 -5 and 4.8 × 10 -6 , respectively, for wind speed of 1 m/s and H/W equal to 1. The ELCR at street level results higher on the leeward side for aspect ratios equal to 1 and 3, while for aspect ratio equal to 2 it is higher on the windward side. In addition, the simulations showed that with the increasing of wind speed the ELCR becomes lower everywhere in the street canyon, due to the increased in dispersion. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Exposure scenario libraries as a tool for exposure assessment

    International Nuclear Information System (INIS)

    Jiménez, Araceli Sánchez; Rashid, Shahzad; Van Tongeren, Martie; Brouwer, Derk; Fransman, Wouter; Fito, Carlos; Boulougouris, George

    2015-01-01

    The development of nanotechnology has reached a point where it is being widely applied, and numerous nanomaterials and nano-enabled products are handled across a broad range of industrial sectors. Exposure extends beyond occupational settings as products containing nanomaterials are used by different consumer groups.Despite the knowledge on their toxic effects is growing there is still not OEL for most NMS and therefore the precautionary approach is still used where levels are kept as low as possible Therefore there is a need to assess workers and consumers exposure. (paper)

  4. A class of non-linear exposure-response models suitable for health impact assessment applicable to large cohort studies of ambient air pollution.

    Science.gov (United States)

    Nasari, Masoud M; Szyszkowicz, Mieczysław; Chen, Hong; Crouse, Daniel; Turner, Michelle C; Jerrett, Michael; Pope, C Arden; Hubbell, Bryan; Fann, Neal; Cohen, Aaron; Gapstur, Susan M; Diver, W Ryan; Stieb, David; Forouzanfar, Mohammad H; Kim, Sun-Young; Olives, Casey; Krewski, Daniel; Burnett, Richard T

    2016-01-01

    The effectiveness of regulatory actions designed to improve air quality is often assessed by predicting changes in public health resulting from their implementation. Risk of premature mortality from long-term exposure to ambient air pollution is the single most important contributor to such assessments and is estimated from observational studies generally assuming a log-linear, no-threshold association between ambient concentrations and death. There has been only limited assessment of this assumption in part because of a lack of methods to estimate the shape of the exposure-response function in very large study populations. In this paper, we propose a new class of variable coefficient risk functions capable of capturing a variety of potentially non-linear associations which are suitable for health impact assessment. We construct the class by defining transformations of concentration as the product of either a linear or log-linear function of concentration multiplied by a logistic weighting function. These risk functions can be estimated using hazard regression survival models with currently available computer software and can accommodate large population-based cohorts which are increasingly being used for this purpose. We illustrate our modeling approach with two large cohort studies of long-term concentrations of ambient air pollution and mortality: the American Cancer Society Cancer Prevention Study II (CPS II) cohort and the Canadian Census Health and Environment Cohort (CanCHEC). We then estimate the number of deaths attributable to changes in fine particulate matter concentrations over the 2000 to 2010 time period in both Canada and the USA using both linear and non-linear hazard function models.

  5. Impact Assessment of Cigarette Smoke Exposure on Organotypic Bronchial Epithelial Tissue Cultures: A Comparison of Mono-Culture and Coculture Model Containing Fibroblasts

    Science.gov (United States)

    Iskandar, Anita R.; Xiang, Yang; Frentzel, Stefan; Talikka, Marja; Leroy, Patrice; Kuehn, Diana; Guedj, Emmanuel; Martin, Florian; Mathis, Carole; Ivanov, Nikolai V.; Peitsch, Manuel C.; Hoeng, Julia

    2015-01-01

    Organotypic 3D cultures of epithelial cells are grown at the air–liquid interface (ALI) and resemble the in vivo counterparts. Although the complexity of in vivo cellular responses could be better manifested in coculture models in which additional cell types such as fibroblasts were incorporated, the presence of another cell type could mask the response of the other. This study reports the impact of whole cigarette smoke (CS) exposure on organotypic mono- and coculture models to evaluate the relevancy of organotypic models for toxicological assessment of aerosols. Two organotypic bronchial models were directly exposed to low and high concentrations of CS of the reference research cigarette 3R4F: monoculture of bronchial epithelial cells without fibroblasts (BR) and coculture with fibroblasts (BRF) models. Adenylate kinase (AK)-based cytotoxicity, cytochrome P450 (CYP) 1A1/1B1 activity, tissue histology, and concentrations of secreted mediators into the basolateral media, as well as transcriptomes were evaluated following the CS exposure. The results demonstrated similar impact of CS on the AK-based cytotoxicity, CYP1A1/1B1 activity, and tissue histology in both models. However, a greater number of secreted mediators was identified in the basolateral media of the monoculture than in the coculture models. Furthermore, annotation analysis and network-based systems biology analysis of the transcriptomic profiles indicated a more prominent cellular stress and tissue damage following CS in the monoculture epithelium model without fibroblasts. Finally, our results indicated that an in vivo smoking-induced xenobiotic metabolism response of bronchial epithelial cells was better reflected from the in vitro CS-exposed coculture model. PMID:26085348

  6. Tools for regulatory assessment of occupational exposure: Development and challenges

    NARCIS (Netherlands)

    Tielemans, E.; Warren, N.; Schneider, T.; Tischer, M.; Ritchie, P.; Goede, H.; Kromhout, H.; Hemmen, J. van; Cherrie, J.W.

    2007-01-01

    REACH (Registration, Evaluation and Authorization of CHemicals) requires improved exposure models that can be incorporated into screening tools and refined assessment tools. These are referred to as tier 1 and 2 models, respectively. There are a number of candidate in tier 1 models that could be

  7. Assessing the reliability of dose coefficients for exposure to radioiodine by members of the public, accounting for dosimetric and risk model uncertainties.

    Science.gov (United States)

    Puncher, M; Zhang, W; Harrison, J D; Wakeford, R

    2017-06-26

    Assessments of risk to a specific population group resulting from internal exposure to a particular radionuclide can be used to assess the reliability of the appropriate International Commission on Radiological Protection (ICRP) dose coefficients used as a radiation protection device for the specified exposure pathway. An estimate of the uncertainty on the associated risk is important for informing judgments on reliability; a derived uncertainty factor, UF, is an estimate of the 95% probable geometric difference between the best risk estimate and the nominal risk and is a useful tool for making this assessment. This paper describes the application of parameter uncertainty analysis to quantify uncertainties resulting from internal exposures to radioiodine by members of the public, specifically 1, 10 and 20-year old females from the population of England and Wales. Best estimates of thyroid cancer incidence risk (lifetime attributable risk) are calculated for ingestion or inhalation of 129 I and 131 I, accounting for uncertainties in biokinetic model and cancer risk model parameter values. These estimates are compared with the equivalent ICRP derived nominal age-, sex- and population-averaged estimates of excess thyroid cancer incidence to obtain UFs. Derived UF values for ingestion or inhalation of 131 I for 1 year, 10-year and 20-year olds are around 28, 12 and 6, respectively, when compared with ICRP Publication 103 nominal values, and 9, 7 and 14, respectively, when compared with ICRP Publication 60 values. Broadly similar results were obtained for 129 I. The uncertainties on risk estimates are largely determined by uncertainties on risk model parameters rather than uncertainties on biokinetic model parameters. An examination of the sensitivity of the results to the risk models and populations used in the calculations show variations in the central estimates of risk of a factor of around 2-3. It is assumed that the direct proportionality of excess thyroid cancer

  8. Assessment of chemical exposures: calculation methods for environmental professionals

    National Research Council Canada - National Science Library

    Daugherty, Jack E

    1997-01-01

    ... on by scientists, businessmen, and policymakers. Assessment of Chemical Exposures: Calculation Methods for Environmental Professionals addresses the expanding scope of exposure assessments in both the workplace and environment...

  9. Assessment and characterisation of yeast-based products intended to mitigate ochratoxin exposure using in vitro and in vivo models.

    Science.gov (United States)

    Pfohl-Leszkowicz, A; Hadjeba-Medjdoub, K; Ballet, N; Schrickx, J; Fink-Gremmels, J

    2015-01-01

    The aim of this paper was to evaluate the capacity of several yeast-based products, derived from baker's and brewer's yeasts, to sequester the mycotoxin ochratoxin A (OTA) and to decrease its rate of absorption and DNA adduct formation in vivo. The experimental protocol included in vitro binding studies using isotherm models, in vivo chicken experiments, in which the serum and tissue concentrations of OTA were analysed in the absence and presence of the test compounds, and the profile of OTA-derived metabolites and their associated DNA adducts were determined. Additionally in vitro cell culture studies (HK2 cells) were applied to assess further the effects for yeast cell product enriched with glutathione (GSH) or selenium. Results of the in vitro binding assay in a buffer system indicated the ability of the yeast-based products, as sequester of OTA, albeit at a different level. In the in vitro experiments in chickens, decreased serum and tissue concentrations of treated animals confirmed that yeast-based products are able to prevent the absorption of OTA. A comparison of the binding affinity in a standard in vitro binding assay with the results obtained in an in vivo chicken experiment, however, showed a poor correlation and resulted in a different ranking of the products. More importantly, we could show that yeast-based products actively modulate the biotransformation of OTA in vivo as well as in vitro in a cell culture model. This effect seems to be attributable to residual enzymatic activities in the yeast-based products. An enrichment of yeast cell wall products with GSH or selenium further modulated the profile of the generated OTA metabolites and the associated pattern of OTA-induced DNA adducts by increasing the conversion of OTA into less toxic metabolites such as OTA, OTB and 4-OH-OTA. A reduced absorption and DNA adduct formation was particularly observed with GSH-enriched yeast, whereas selenium-enriched yeasts could counteract the OTA-induced decrease

  10. Exposure dose assessment using bioassay

    International Nuclear Information System (INIS)

    Suga, Shinichi

    1994-01-01

    Bioassay involves following steps: sampling, pre-treatment, chemical separation and counting of radioactivity. As bioassay samples, urines are usually used, although faecal analysis may be required in some occasions for example to assess intake of non-transferable radioactive materials. Nasal smear is a useful indicator of an inhalation case. Exhalation air is used to estimate the intake of tritiated water. Sample pre-treatment includes evaporation for concentration, wet ashing, dry ashing and co-precipitation. After adding small amount of nitric acid, the sample can be concentrated by 1/10 of initial volume, which may be used to identify γ-emitters. As the pre-treatment of urine, wet ashing is used for example for analysis of Pu, and co-precipitation is used for example for analysis of Sr. Dry ashing by electric furnace is usually adopted for faecal samples. Methods of chemical separation depend on the radionuclide(s) to be analysed. The detection limit depends also on radionuclide, and for example typical detection limits are 0.4Bq / l (volume of urine sample) for 89 Sr or 90 Sr, and 0.01 Bq / l with urine and 0.01 Bq per sample with faeces for 238 Pu, 239 Pu or 241 Am. Simpler methods can be used for some radionuclides: For example, radioactivity concentration of tritium can be determined by liquid scintillation counting of urine or condensed water from exhaled air, and natural uranium in urine can be quantified by using fluorometric method. In some circumstances, gross-α or gross-β analyses are useful for quick estimation. To estimate intakes by inhalation or by ingestion from bioassay results and to assess the committed dose equivalent, commonly available bases are the relevant publications by the ICRP and domestic guides and manuals that conform to the radiation protection regulations. (author)

  11. Modeling individual movement decisions of brown hare (Lepus europaeus) as a key concept for realistic spatial behavior and exposure: A population model for landscape-level risk assessment.

    Science.gov (United States)

    Kleinmann, Joachim U; Wang, Magnus

    2017-09-01

    Spatial behavior is of crucial importance for the risk assessment of pesticides and for the assessment of effects of agricultural practice or multiple stressors, because it determines field use, exposition, and recovery. Recently, population models have increasingly been used to understand the mechanisms driving risk and recovery or to conduct landscape-level risk assessments. To include spatial behavior appropriately in population models for use in risk assessments, a new method, "probabilistic walk," was developed, which simulates the detailed daily movement of individuals by taking into account food resources, vegetation cover, and the presence of conspecifics. At each movement step, animals decide where to move next based on probabilities being determined from this information. The model was parameterized to simulate populations of brown hares (Lepus europaeus). A detailed validation of the model demonstrated that it can realistically reproduce various natural patterns of brown hare ecology and behavior. Simulated proportions of time animals spent in fields (PT values) were also comparable to field observations. It is shown that these important parameters for the risk assessment may, however, vary in different landscapes. The results demonstrate the value of using population models to reduce uncertainties in risk assessment and to better understand which factors determine risk in a landscape context. Environ Toxicol Chem 2017;36:2299-2307. © 2017 SETAC. © 2017 SETAC.

  12. [Occupational exposure to nanoparticles. Assessment of workplace exposure].

    Science.gov (United States)

    Bujak-Pietrek, Stella

    2010-01-01

    Nanotechnology is currently one of the most popular branch of science. It is a technology that enables designing, manufacturing and application of materials and structures of very small dimensions, and its products are applied in almost every field of life. Nanoparticles are the structures having one or more dimensions of the order of 100 nm or less. They are used in precise mechanics, electronics, optics, medicine, pharmacy, cosmetics and many other spheres. Due to their very small size, nanostructures have completely different and specific properties, unknown for the bulk of materials. Fast-growing nanotechnology provides a wide spectrum of applications, but it also brings about new and unknown danger to human health. Nanotechnology is the branch that has developed rather recently, and much information about health risk and its influence on the environment is beyond our knowledge. Nanoparticles, released in many technological processes, as well as manufactured nanoparticles can induce occupational hazards to workers. The lack of regulations and standards, compulsory in the manufacture and use ofnanoparticles is a fundamental problem faced in the evaluation of exposure. Another problem is the choice of proper measurement equipment for surveying of very small particles - their number, mass and surface area in the workpost air. In this article, the possibility and scope of exposure assessment is discussed and a brief specification of available instrumentation for counting and assessing the parameters essential for classifying the exposure to nanoparticles is presented.

  13. Mobile phone tracking: in support of modelling traffic-related air pollution contribution to individual exposure and its implications for public health impact assessment

    Science.gov (United States)

    2013-01-01

    We propose a new approach to assess the impact of traffic-related air pollution on public health by mapping personal trajectories using mobile phone tracking technology in an urban environment. Although this approach is not based on any empirical studies, we believe that this method has great potential and deserves serious attention. Mobile phone tracking technology makes it feasible to generate millions of personal trajectories and thereby cover a large fraction of an urban population. Through analysis, personal trajectories are not only associated to persons, but it can also be associated with vehicles, vehicle type, vehicle speed, vehicle emission rates, and sources of vehicle emissions. Pollution levels can be estimated by dispersion models from calculated traffic emissions. Traffic pollution exposure to individuals can be estimated based on the exposure along the individual human trajectories in the estimated pollution concentration fields by utilizing modelling tools. By data integration, one may identify trajectory patterns of particularly exposed human groups. The approach of personal trajectories may open a new paradigm in understanding urban dynamics and new perspectives in population-wide empirical public health research. This new approach can be further applied to individual commuter route planning, land use planning, urban traffic network planning, and used by authorities to formulate air pollution mitigation policies and regulations. PMID:24188173

  14. Perspectives for integrating human and environmental exposure assessments.

    Science.gov (United States)

    Ciffroy, P; Péry, A R R; Roth, N

    2016-10-15

    Integrated Risk Assessment (IRA) has been defined by the EU FP7 HEROIC Coordination action as "the mutual exploitation of Environmental Risk Assessment for Human Health Risk Assessment and vice versa in order to coherently and more efficiently characterize an overall risk to humans and the environment for better informing the risk analysis process" (Wilks et al., 2015). Since exposure assessment and hazard characterization are the pillars of risk assessment, integrating Environmental Exposure assessment (EEA) and Human Exposure assessment (HEA) is a major component of an IRA framework. EEA and HEA typically pursue different targets, protection goals and timeframe. However, human and wildlife species also share the same environment and they similarly inhale air and ingest water and food through often similar overlapping pathways of exposure. Fate models used in EEA and HEA to predict the chemicals distribution among physical and biological media are essentially based on common properties of chemicals, and internal concentration estimations are largely based on inter-species (i.e. biota-to-human) extrapolations. Also, both EEA and HEA are challenged by increasing scientific complexity and resources constraints. Altogether, these points create the need for a better exploitation of all currently existing data, experimental approaches and modeling tools and it is assumed that a more integrated approach of both EEA and HEA may be part of the solution. Based on the outcome of an Expert Workshop on Extrapolations in Integrated Exposure Assessment organized by the HEROIC project in January 2014, this paper identifies perspectives and recommendations to better harmonize and extrapolate exposure assessment data, models and methods between Human Health and Environmental Risk Assessments to support the further development and promotion of the concept of IRA. Ultimately, these recommendations may feed into guidance showing when and how to apply IRA in the regulatory decision

  15. Polybrominated Diphenyl Ethers in Human Milk and Serum from the U.S. EPA MAMA Study: Modeled Predictions of Infant Exposure and Considerations for Risk Assessment

    Science.gov (United States)

    Marchitti, Satori A.; Fenton, Suzanne E.; Mendola, Pauline; Kenneke, John F.; Hines, Erin P.

    2016-01-01

    Background: Serum concentrations of polybrominated diphenyl ethers (PBDEs) in U.S. women are believed to be among the world’s highest; however, little information exists on the partitioning of PBDEs between serum and breast milk and how this may affect infant exposure. Objectives: Paired milk and serum samples were measured for PBDE concentrations in 34 women who participated in the U.S. EPA MAMA Study. Computational models for predicting milk PBDE concentrations from serum were evaluated. Methods: Samples were analyzed using gas chromatography isotope-dilution high-resolution mass spectrometry. Observed milk PBDE concentrations were compared with model predictions, and models were applied to NHANES serum data to predict milk PBDE concentrations and infant intakes for the U.S. population. Results: Serum and milk samples had detectable concentrations of most PBDEs. BDE-47 was found in the highest concentrations (median serum: 18.6; milk: 31.5 ng/g lipid) and BDE-28 had the highest milk:serum partitioning ratio (2.1 ± 0.2). No evidence of depuration was found. Models demonstrated high reliability and, as of 2007–2008, predicted U.S. milk concentrations of BDE-47, BDE-99, and BDE-100 appear to be declining but BDE-153 may be rising. Predicted infant intakes (ng/kg/day) were below threshold reference doses (RfDs) for BDE-99 and BDE-153 but above the suggested RfD for BDE-47. Conclusions: Concentrations and partitioning ratios of PBDEs in milk and serum from women in the U.S. EPA MAMA Study are presented for the first time; modeled predictions of milk PBDE concentrations using serum concentrations appear to be a valid method for estimating PBDE exposure in U.S. infants. Citation: Marchitti SA, Fenton SE, Mendola P, Kenneke JF, Hines EP. 2017. Polybrominated diphenyl ethers in human milk and serum from the U.S. EPA MAMA Study: modeled predictions of infant exposure and considerations for risk assessment. Environ Health Perspect 125:706–713; http://dx.doi.org/10

  16. Air Pollution Exposure Modeling for Health Studies | Science ...

    Science.gov (United States)

    Dr. Michael Breen is leading the development of air pollution exposure models, integrated with novel personal sensor technologies, to improve exposure and risk assessments for individuals in health studies. He is co-investigator for multiple health studies assessing the exposure and effects of air pollutants. These health studies include participants with asthma, diabetes, and coronary artery disease living in various U.S. cities. He has developed, evaluated, and applied novel exposure modeling and time-activity tools, which includes the Exposure Model for Individuals (EMI), GPS-based Microenvironment Tracker (MicroTrac) and Exposure Tracker models. At this seminar, Dr. Breen will present the development and application of these models to predict individual-level personal exposures to particulate matter (PM) for two health studies in central North Carolina. These health studies examine the association between PM and adverse health outcomes for susceptible individuals. During Dr. Breen’s visit, he will also have the opportunity to establish additional collaborations with researchers at Harvard University that may benefit from the use of exposure models for cohort health studies. These research projects that link air pollution exposure with adverse health outcomes benefit EPA by developing model-predicted exposure-dose metrics for individuals in health studies to improve the understanding of exposure-response behavior of air pollutants, and to reduce participant

  17. A Study on the Use of Compound and Extracted Models in the High Frequency Electromagnetic Exposure Assessment

    Directory of Open Access Journals (Sweden)

    Mario Cvetković

    2017-01-01

    Full Text Available The paper presents the numerical results for the induced electric field in the various models of the human eye and the head. The comparison between the extracted or the single organ models and the compound organ models placed inside realistic head models obtained from the magnetic resonance imaging scans is presented. The numerical results for several frequencies and polarizations of the incident electromagnetic (EM plane wave are obtained using the hybrid finite element method/boundary element method (FEM/BEM formulation and the surface integral equation (SIE based formulation featuring the use of method of moments, respectively. Although some previous analysis showed the similar distribution of the induced electric field along the pupillary axis obtained in both eye models, this study showed this not to be the case in general. The analysis showed that the compound eye model is much more suitable when taking into account the polarization of the incident EM wave. The numerical results for the brain models showed much better agreement in the maximum values and distributions of the induced surface field between detailed models, while homogeneous brain model showed better agreement with the compound model in the distribution along selected sagittal axis points. The analysis could provide some helpful insights when carrying out the dosimetric analysis of the human eye and the head/brain exposed to high frequency EM radiation.

  18. Combination of a higher-tier flow-through system and population modeling to assess the effects of time-variable exposure of isoproturon on the green algae Desmodesmus subspicatus and Pseudokirchneriella subcapitata.

    Science.gov (United States)

    Weber, Denis; Schaefer, Dieter; Dorgerloh, Michael; Bruns, Eric; Goerlitz, Gerhard; Hammel, Klaus; Preuss, Thomas G; Ratte, Hans Toni

    2012-04-01

    A flow-through system was developed to investigate the effects of time-variable exposure of pesticides on algae. A recently developed algae population model was used for simulations supported and verified by laboratory experiments. Flow-through studies with Desmodesmus subspicatus and Pseudokirchneriella subcapitata under time-variable exposure to isoproturon were performed, in which the exposure patterns were based on the results of FOrum for Co-ordination of pesticide fate models and their USe (FOCUS) model calculations for typical exposure situations via runoff or drain flow. Different types of pulsed exposure events were realized, including a whole range of repeated pulsed and steep peaks as well as periods of constant exposure. Both species recovered quickly in terms of growth from short-term exposure and according to substance dissipation from the system. Even at a peak 10 times the maximum predicted environmental concentration of isoproturon, only transient effects occurred on algae populations. No modified sensitivity or reduced growth was observed after repeated exposure. Model predictions of algal growth in the flow-through tests agreed well with the experimental data. The experimental boundary conditions and the physiological properties of the algae were used as the only model input. No calibration or parameter fitting was necessary. The combination of the flow-through experiments with the algae population model was revealed to be a powerful tool for the assessment of pulsed exposure on algae. It allowed investigating the growth reduction and recovery potential of algae after complex exposure, which is not possible with standard laboratory experiments alone. The results of the combined approach confirm the beneficial use of population models as supporting tools in higher-tier risk assessments of pesticides. Copyright © 2012 SETAC.

  19. The ChimERA project: Coupling mechanistic exposure and effect models into an integrated platform for ecological risk assessment

    NARCIS (Netherlands)

    Laender, de F.; Brink, van den P.J.; Janssen, C.R.; Guardo, Di A.

    2014-01-01

    Current techniques for the ecological risk assessment of chemical substances are often criticised for their lack of environmental realism, ecological relevance and methodological accuracy. ChimERA is a 3-year project (2013-2016), funded by Cefic's Long Range Initiative (LRI) that aims to address

  20. Probabilistic quantitative microbial risk assessment model of farmer exposure to Cryptosporidium spp. in irrigation water within Kumasi Metropolis-Ghana

    DEFF Research Database (Denmark)

    Sampson, Angelina; Owusu-Ansah, Emmanuel de-Graft Johnson; Mills-Robertson, Felix C.

    2017-01-01

    causing gastroenteritis. The results indicate high positive levels of Cryptosporidium in the irrigation water, however, the levels of Cryptosporidium decreases during the rainfall seasons, risk assessment results show that, farmers face a higher risk of being infected by Cryptosporidium due to frequent...

  1. A Health Hazard Assessment for Blast Overpressure Exposures Subtitle - Biological Response to Blast Overpressure: A Summary of Modeling

    National Research Council Canada - National Science Library

    Stuhmiller, James

    1996-01-01

    .... For the past 15 years, JAYCOR, working together with the Walter Reed Army Institute of Research, has been using modeling, simulation, and data analysis to determine the nature of injury in animal...

  2. ASSESSMENT OF HUMAN EXPOSURE TO TOLUENE DIISOCYANATE

    Directory of Open Access Journals (Sweden)

    OLIVIA ANCA RUSU

    2011-03-01

    Full Text Available Assessment of human exposure to toluene diisocyanate. Toluene diisocyanate (TDI, an aromatic compound, may be dangerous for human health. Diisocyanates have wide industrial use in the fabrication of flexible and rigid foams, fibers, elastomers, and coatings such as paints and varnishes. Isocyanates are known skin and respiratory sensitizers, and proper engineering controls should be in place to prevent exposure to isocyanate liquid and vapor; exposure to TDI vapors is well documented to increase asthma risk. The study focused on the exposure of workers and nearby populations to toluene diisocyanate in a Polyurethane Foam Factory located in Baia Mare, Romania. Workplace air measurements were performed in different departments of the plant, after sampling either in fixed points or as personal monitoring. Sampling in four different locations of Baia Mare town was carried out, - during and after the foaming process. TDI sampling was performed on silica cartridge followed by GC-MS analysis. TDI concentration at workplace was lower than 0,035 mg/m³, which represents the permissible exposure limit, while in the city the TDI concentration had shown values below 0,20 μg/m³. Health assessment of a group of 49 workers was based on questionnaire interview, determination of TDI antibodies and lung function tests. Data collected until this stage do not show any negative effects of TDI on the employees health. Since this plant had only recently begun operating, continuous workplace and ambient air TDI monitoring, along with workers health surveillance, is deemed necessary.

  3. Conceptual Framework To Extend Life Cycle Assessment Using Near-Field Human Exposure Modeling and High-Throughput Tools for Chemicals.

    Science.gov (United States)

    Csiszar, Susan A; Meyer, David E; Dionisio, Kathie L; Egeghy, Peter; Isaacs, Kristin K; Price, Paul S; Scanlon, Kelly A; Tan, Yu-Mei; Thomas, Kent; Vallero, Daniel; Bare, Jane C

    2016-11-01

    Life Cycle Assessment (LCA) is a decision-making tool that accounts for multiple impacts across the life cycle of a product or service. This paper presents a conceptual framework to integrate human health impact assessment with risk screening approaches to extend LCA to include near-field chemical sources (e.g., those originating from consumer products and building materials) that have traditionally been excluded from LCA. A new generation of rapid human exposure modeling and high-throughput toxicity testing is transforming chemical risk prioritization and provides an opportunity for integration of screening-level risk assessment (RA) with LCA. The combined LCA and RA approach considers environmental impacts of products alongside risks to human health, which is consistent with regulatory frameworks addressing RA within a sustainability mindset. A case study is presented to juxtapose LCA and risk screening approaches for a chemical used in a consumer product. The case study demonstrates how these new risk screening tools can be used to inform toxicity impact estimates in LCA and highlights needs for future research. The framework provides a basis for developing tools and methods to support decision making on the use of chemicals in products.

  4. Added value of experts' knowledge to improve a quantitative microbial exposure assessment model--Application to aseptic-UHT food products.

    Science.gov (United States)

    Pujol, Laure; Johnson, Nicholas Brian; Magras, Catherine; Albert, Isabelle; Membré, Jeanne-Marie

    2015-10-15

    In a previous study, a quantitative microbial exposure assessment (QMEA) model applied to an aseptic-UHT food process was developed [Pujol, L., Albert, I., Magras, C., Johnson, N. B., Membré, J. M. Probabilistic exposure assessment model to estimate aseptic UHT product failure rate. 2015 International Journal of Food Microbiology. 192, 124-141]. It quantified Sterility Failure Rate (SFR) associated with Bacillus cereus and Geobacillus stearothermophilus per process module (nine modules in total from raw material reception to end-product storage). Previously, the probabilistic model inputs were set by experts (using knowledge and in-house data). However, only the variability dimension was taken into account. The model was then improved using expert elicitation knowledge in two ways. First, the model was refined by adding the uncertainty dimension to the probabilistic inputs, enabling to set a second order Monte Carlo analysis. The eight following inputs, and their impact on SFR, are presented in detail in this present study: D-value for each bacteria of interest (B. cereus and G. stearothermophilus) associated with the inactivation model for the UHT treatment step, i.e., two inputs; log reduction (decimal reduction) number associated with the inactivation model for the packaging sterilization step for each bacterium and each part of the packaging (product container and sealing component), i.e., four inputs; and bacterial spore air load of the aseptic tank and the filler cabinet rooms, i.e., two inputs. Second, the model was improved by leveraging expert knowledge to develop further the existing model. The proportion of bacteria in the product which settled on surface of pipes (between the UHT treatment and the aseptic tank on one hand, and between the aseptic tank and the filler cabinet on the other hand) leading to a possible biofilm formation for each bacterium, was better characterized. It was modeled as a function of the hygienic design level of the aseptic

  5. Opportunities for using spatial property assessment data in air pollution exposure assessments

    Directory of Open Access Journals (Sweden)

    Keller C Peter

    2005-10-01

    Full Text Available Abstract Background Many epidemiological studies examining the relationships between adverse health outcomes and exposure to air pollutants use ambient air pollution measurements as a proxy for personal exposure levels. When pollution levels vary at neighbourhood levels, using ambient pollution data from sparsely located fixed monitors may inadequately capture the spatial variation in ambient pollution. A major constraint to moving toward exposure assessments and epidemiological studies of air pollution at a neighbourhood level is the lack of readily available data at appropriate spatial resolutions. Spatial property assessment data are widely available in North America and may provide an opportunity for developing neighbourhood level air pollution exposure assessments. Results This paper provides a detailed description of spatial property assessment data available in the Pacific Northwest of Canada and the United States, and provides examples of potential applications of spatial property assessment data for improving air pollution exposure assessment at the neighbourhood scale, including: (1 creating variables for use in land use regression modelling of neighbourhood levels of ambient air pollution; (2 enhancing wood smoke exposure estimates by mapping fireplace locations; and (3 using data available on individual building characteristics to produce a regional air pollution infiltration model. Conclusion Spatial property assessment data are an extremely detailed data source at a fine spatial resolution, and therefore a source of information that could improve the quality and spatial resolution of current air pollution exposure assessments.

  6. Simplified fate, exposure and effect modelling of chemical compounds in the case of lacking complete assessment data sets

    DEFF Research Database (Denmark)

    Birkved, Morten; Heijungs, R; Olsen, Stig Irving

    2004-01-01

    availability limitations to select key parameters that explain much of the variance and at the same time are relatively easily available. Further, PLSR was used to derive linear SBM models. In further investigations multiple linear regression (MLR) will be used to derive predictive equations for SBM...... characterisation factors. The result of this will be tested on common sense and environmental knowledge and a mechanistically understandable SBM will be developed by rounding off the coefficients of the regression equations. Preliminary results including PLSR derived linear SBM’s of this work is presented........g. in terms of how the input parameters enter the regression equation. In the absence of a final OMNIITOX BM a model of similar complexity USES-LCA, has been used as surrogate BM. We have applied partial least square of latent structure regression (PLSR) and combined insights from this with knowledge on data...

  7. Development of a pathway model to assess the exposure of European pine trees to pine wood nematode via the trade of wood.

    Science.gov (United States)

    Douma, J C; van der Werf, W; Hemerik, L; Magnusson, C; Robinet, C

    2017-04-01

    Pine wood nematode (PWN), Bursaphelenchus xylophilus, is a threat for pine species (Pinus spp.) throughout the world. The nematode is native to North America, and invaded Japan, China, Korea, and Taiwan, and more recently Portugal and Spain. PWN enters new areas through trade in wood products. Once established, eradication is not practically feasible. Therefore, preventing entry of PWN into new areas is crucial. Entry risk analysis can assist in targeting management to reduce the probability of entry. Assessing the entry of PWN is challenging due to the complexity of the wood trade and the wood processing chain. In this paper, we develop a pathway model that describes the wood trade and wood processing chain to determine the structure of the entry process. We consider entry of PWN through imported coniferous wood from China, a possible origin of Portuguese populations, to Europe. We show that exposure increased over years due to an increase in imports of sawn wood. From 2000 to 2012, Europe received an estimated 84 PWN propagules from China, 88% of which arose from imported sawn wood and 12% from round wood. The region in Portugal where the PWN was first reported is among those with the highest PWN transfer per unit of imported wood due to a high host cover and vector activity. An estimated 62% of PWN is expected to enter in countries where PWN is not expected to cause the wilt of pine trees because of low summer temperatures (e.g., Belgium, Sweden, Norway). In these countries, PWN is not easily detected, and such countries can thus serve as potential reservoirs of PWN. The model identifies ports and regions with high exposure, which helps targeting monitoring and surveillance, even in areas where wilt disease is not expected to occur. In addition, we show that exposure is most efficiently reduced by additional treatments in the country of origin, and/or import wood from PWN-free zones. Pathway modelling assists plant health managers in analyzing risks along the

  8. DynaPop-X: A population dynamics model applied to spatio-temporal exposure assessment - Implementation aspects from the CRISMA project

    Science.gov (United States)

    Aubrecht, Christoph; Steinnocher, Klaus; Humer, Heinrich; Huber, Hermann

    2014-05-01

    In the context of proactive disaster risk as well as immediate situational crisis management knowledge of locational social aspects in terms of spatio-temporal population distribution dynamics is considered among the most important factors for disaster impact minimization (Aubrecht et al., 2013a). This applies to both the pre-event stage for designing appropriate preparedness measures and to acute crisis situations when an event chain actually unfolds for efficient situation-aware response. The presented DynaPop population dynamics model is developed at the interface of those interlinked crisis stages and aims at providing basic input for social impact evaluation and decision support in crisis management. The model provides the starting point for assessing population exposure dynamics - thus here labeled as DynaPop-X - which can either be applied in a sense of illustrating the changing locations and numbers of affected people at different stages during an event or as ex-ante estimations of probable and maximum expected clusters of affected population (Aubrecht et al., 2013b; Freire & Aubrecht, 2012). DynaPop is implemented via a gridded spatial disaggregation approach and integrates previous efforts on spatio-temporal modeling that account for various aspects of population dynamics such as human mobility and activity patterns that are particularly relevant in picturing the highly dynamic daytime situation (Ahola et al., 2007; Bhaduri, 2008; Cockings et al., 2010). We will present ongoing developments particularly focusing on the implementation logic of the model using the emikat software tool, a data management system initially designed for inventorying and analysis of spatially resolved regional air pollutant emission scenarios. This study was performed in the framework of the EU CRISMA project. CRISMA is funded from the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement no. 284552. REFERENCES Ahola, T., Virrantaus, K., Krisp, J

  9. Assessing asbestos exposure potential in nonindustrial settings.

    Science.gov (United States)

    Chang, S N; White, L E; Scott, W D

    1987-01-01

    The presence of asbestos containing materials (ACM) in office and commercial buildings is a significant environmental problem. Asbestosis, mesothelioma and lung cancer have been linked with industrial exposure to airborne asbestos. The extensive use of asbestos products in buildings has raised concerns about the widespread exposure of the general public to asbestos in nonoccupational settings. The presence of asbestos in a building does not necessarily mean that significant exposure of the occupants of the building has occurred, but it is important that the asbestos be monitored regularly to ensure that fibers do not become airborne. If ACM are contained within a matrix and not disturbed, exposure is unlikely. However, if the asbestos becomes friable (crumbling) or if building maintenance, repair, renovation or other activities disturb ACM, airborne asbestos fibers may be a source of exposure to the occupants of the building. Currently, asbestos exposure assessment is conducted by a phase contrast light microscope (PCM) technique. Due to its inherent limitation in resolution and the generic counting rules used, analysis by the PCM method underestimates the airborne asbestos fiber concentration as compared to analysis by transmission electron microscopy (TEM). It is important that the air monitoring results analyzed by PCM be interpreted carefully in conjunction with a survey by a professional to judge the physical condition of the ACM in buildings. Exposure levels to airborne asbestos fibers vary from day to day and depend on the physical condition of the material involved and the type of operating and maintenance program in place.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. An energetics-based honeybee nectar-foraging model used to assess the potential for landscape-level pesticide exposure dilution

    Directory of Open Access Journals (Sweden)

    Johannes M. Baveco

    2016-08-01

    Full Text Available Estimating the exposure of honeybees to pesticides on a landscape scale requires models of their spatial foraging behaviour. For this purpose, we developed a mechanistic, energetics-based model for a single day of nectar foraging in complex landscape mosaics. Net energetic efficiency determined resource patch choice. In one version of the model a single optimal patch was selected each hour. In another version, recruitment of foragers was simulated and several patches could be exploited simultaneously. Resource availability changed during the day due to depletion and/or intrinsic properties of the resource (anthesis. The model accounted for the impact of patch distance and size, resource depletion and replenishment, competition with other nectar foragers, and seasonal and diurnal patterns in availability of nectar-providing crops and wild flowers. From the model we derived simple rules for resource patch selection, e.g., for landscapes with mass-flowering crops only, net energetic efficiency would be proportional to the ratio of the energetic content of the nectar divided by distance to the hive. We also determined maximum distances at which resources like oilseed rape and clover were still energetically attractive. We used the model to assess the potential for pesticide exposure dilution in landscapes of different composition and complexity. Dilution means a lower concentration in nectar arriving at the hive compared to the concentration in nectar at a treated field and can result from foraging effort being diverted away from treated fields. Applying the model for all possible hive locations over a large area, distributions of dilution factors were obtained that were characterised by their 90-percentile value. For an area for which detailed spatial data on crops and off-field semi-natural habitats were available, we tested three landscape management scenarios that were expected to lead to exposure dilution: providing alternative resources than

  11. AirPEx: Air Pollution Exposure Model

    NARCIS (Netherlands)

    Freijer JI; Bloemen HJTh; Loos S de; Marra M; Rombout PJA; Steentjes GM; Veen MP van; LBO

    1997-01-01

    Analysis of inhalatory exposure to air pollution is an important area of investigation when assessing the risks of air pollution for human health. Inhalatory exposure research focuses on the exposure of humans to air pollutants and the entry of these pollutants into the human respiratory tract. The

  12. Incorporation of additional radionuclides and the external exposure pathway into the BECAMP [Basic Environmental Compliance and Monitoring Program] radiological assessment model

    International Nuclear Information System (INIS)

    Ng, Yook C.; Rodean, H.C.; Anspaugh, L.R.

    1988-11-01

    The Nevada Applied Ecology Group (NAEG) Model of transport and dose for transuranic radionuclides was modified and expanded for the analysis of radionuclides other than pure alpha-emitters. Doses from internal and external exposures were estimated for the inventories and soil distributions of the individual radionuclides quantified in Areas 2 and 4 of the Nevada Test Site (NTS). We found that the dose equivalents via inhalation to liver, lungs, bone marrow, and bone surface from the plutonium isotopes and 241 Am, those via ingestion to bone marrow and bone surfaces from 90 Sr, and those via ingestion to all the target organs from 137 Cs were the highest from internal exposures. The effective dose equivalents from 137 Cs, 152 Eu, and 154 Eu were the highest from the external exposures. The 60 Co, 152 Eu, 154 Eu, and 155 Eu dose estimates for external exposures greatly exceeded those for internal exposures. The 60 Co, 90 Sr, and 137 Cs dose equivalents from internal exposures were underestimated due to the adoption of some of the foodchain parameter values originally selected for 239 Pu. Nonetheless, the ingestion pathway contributed significantly to the dose estimates for 90 Sr and 137 Cs, but contributed very much less than external exposures to the dose estimates for 60 Co. Therefore, the use of more appropriate values would not alter the identification of important radionuclides, pathways, target organs, and exposure modes in this analysis. 19 refs., 13 figs., 12 tabs

  13. EPa`s program for risk assessment guidelines: Exposure issues

    Energy Technology Data Exchange (ETDEWEB)

    Callahan, M.A. [Environmental Protection Agency, Washington, DC (United States)

    1990-12-31

    Three major issues to be dealt with over the next ten years in the exposure assessment field are: consistency in terminology, the impact of computer technology on the choice of data and modeling, and conceptual issues such as the use of time-weighted averages.

  14. Assessment of exposure dose to workers in virtual decommissioning environments

    International Nuclear Information System (INIS)

    Jeong, KwanSeong; Moon, JeiKwon; Choi, ByungSeon; Hyun, Dongjun; Lee, Jonghwan; Kim, Ikjune; Kim, GeunHo; Seo, JaeSeok

    2014-01-01

    This paper is intended to suggest the method analyze and assess the exposure dose to workers in virtual decommissioning environments. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. This work was to be able to simulate scenarios of decommissioning so that exposure dose to workers could be measured and assessed. To establish the plan of exposure dose to workers during decommissioning of nuclear facilities before decommissioning activities are accomplished, the method of simulation assessment was developed in virtual radiological environments. But this work was developed as a tool of simulation for single subject mode. Afterwards, the simulation environment for multi-subjects mode will be upgraded by simultaneous modules with networking environments. Then the much more practical method will be developed by changing number of workers and duration of time under any circumstances of decommissioning

  15. Assessment of exposure dose to workers in virtual decommissioning environments

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, KwanSeong; Moon, JeiKwon; Choi, ByungSeon; Hyun, Dongjun; Lee, Jonghwan; Kim, Ikjune; Kim, GeunHo; Seo, JaeSeok [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2014-10-15

    This paper is intended to suggest the method analyze and assess the exposure dose to workers in virtual decommissioning environments. To simulate a lot of decommissioning scenarios, decommissioning environments were designed in virtual reality. To simulate and assess the exposure dose to workers, human model also was designed in virtual environments. These virtual decommissioning environments made it possible to real-time simulate and assess the exposure dose to workers. This work was to be able to simulate scenarios of decommissioning so that exposure dose to workers could be measured and assessed. To establish the plan of exposure dose to workers during decommissioning of nuclear facilities before decommissioning activities are accomplished, the method of simulation assessment was developed in virtual radiological environments. But this work was developed as a tool of simulation for single subject mode. Afterwards, the simulation environment for multi-subjects mode will be upgraded by simultaneous modules with networking environments. Then the much more practical method will be developed by changing number of workers and duration of time under any circumstances of decommissioning.

  16. Exposure Assessment of Diesel Bus Emissions

    Directory of Open Access Journals (Sweden)

    Werner Hofmann

    2006-12-01

    Full Text Available The goal of this study was to measure ultrafine particle concentrations with diameters less than 1 μm emitted by diesel buses and to assess resulting human exposure levels. The study was conducted at the Woolloongabba Busway station in Brisbane, Australia in the winter months of 2002 during which temperature inversions frequently occurred. Most buses that utilize the station are fuelled by diesel, the exhaust of which contains a significant quantity of particle matter. Passengers waiting at the station are exposed to these particles emitted from the buses. During the course of this study, passenger census was conducted, based on video surveillance, yielding person-by-person waiting time data. Furthermore, a bus census revealed accurate information about the total number of diesel versus Compressed Natural Gas (CNG powered buses. Background (outside of the bus station and platform measurements of ultrafine particulate number size distributions were made to determine ambient aerosol concentrations. Particle number exposure concentration ranges from 10 and 40 to 60% of bus related exhaust fumes. This changes dramatically when considering the particle mass exposure concentration, where most passengers are exposed to about 50 to 80% of exhaust fumes. The obtained data can be very significant for comparison with similar work of this type because it is shown in previous studies that exhaust emissions causes cancer in laboratory animals. It was assumed that significant differences between platform and background distributions were due to bus emissions which, combined with passenger waiting times, yielded an estimate of passenger exposure to ultrafine particles from diesel buses. From an exposure point of view, the Busway station analyzed resembles a street canyon. Although the detected exhaust particle concentration at the outbound platform is found to be in the picogram range, exposure increases with the time passengers spend on the platform

  17. Computational assessment of pregnant woman models exposed to uniform ELF-magnetic fields: compliance with the European current exposure regulations for the general public and occupational exposures at 50 Hz

    International Nuclear Information System (INIS)

    Liorni, Ilaria; Parazzini, Marta; Fiocchi, Serena; Ravazzani, Paolo; Douglas, Mark; Capstick, Myles; Kuster, Niels

    2016-01-01

    The Recommendation 1999/529/EU and the Directive 2013/35/EU suggest limits for both general public and occupational exposures to extremely low-frequency magnetic fields, but without special limits for pregnant women. This study aimed to assess the compliance of pregnant women to the current regulations, when exposed to uniform MF at 50 Hz (100 μT for EU Recommendation and 1 and 6 mT for EU Directive). For general public, exposure of pregnant women and fetus always resulted in compliance with EU Recommendation. For occupational exposures, (1) Electric fields in pregnant women were in compliance with the Directive, with exposure variations due to fetal posture of 40 % in head tissues, (3) Electric fields in fetal CNS tissues of head are above the ICNIRP 2010 limits for general public at 1 mT (in 7 and 9 months gestational age) and at 6 mT (in all gestational ages). (authors)

  18. Radiation exposure to natural radioactivity in crude oil and petroleum waste from oil fields in Ghana: modelling, risk assessment and regulatory control

    International Nuclear Information System (INIS)

    Kpeglo, D. O.

    2015-06-01

    In this research work radiological hazards and risks to members of the public and workers from exposure to natural radioactivity as a result of crude oil production activities and waste generation from the Saltpond and Jubilee oilfields of Ghana, have been investigated via several exposure pathways using alpha spectrometry after radiochemical separation, nondestructive gamma spectrometry, Scanning Electron Microscope (SEM) and Inductively Coupled Plasma Quadrupole-Based Mass Spectrometry (ICP-QMS) and other complimentary analytical tools. Additionally, in this study a Human health risk assessment model for cancer risk associated with NORM (Naturally Occurring Radioactive Material) components in produced water was developed. Characterization and determination of specific activities of 234 U, 238 U, 210 Po, 230 Th, 2 3 2 Th, 226 Ra, 210 Pb, 234 Th, 228 Ra, 228 Th, 224 Ra, and 40 K for several environmental and NORM waste samples in different matrices have been established. The elements Al, Ba, Ca, Cl, Cu, Fe, K, Mg, Na, P, Pb S, Si, Sr, and Zn were identified and semi qualitatively quantified by Scanning Electron Microscope for NORM waste samples. The total annual effective dose of 0.35 mSv.y -1 obtained for all exposure pathways for the public in this study was below the International Commission on Radiological Protection (ICRP) recommended dose limit of 1 mSv.y -1 for members of the public, whilst the total annual effective dose of 80.86 mSv.y -1 obtained in this study for workers clearly exceeded the ICRP recommended dose limit for an occupationally exposed worker of 20 mSv.y -1 , averaged over 5 years, but not exceeding 50 mSv.y -1 in any single year. The estimated total lifetime fatality cancer risk and the lifetime hereditary effect values were 1.3 x 10 -3 and 4.9 x 10 -5 for the public, and 23.2 x 10 -2 and 5.7 x 10 -3 for adult workers respectively. In conclusion, radium concentrations obtained in this study for scale, sludge and produced water from the

  19. How Exposure Science can be Integrated into the Assessment ...

    Science.gov (United States)

    The presentation describes ongoing research in the Rapid Exposure and Dosimetry project funded under the Chemical Safety for Sustainability Research Program of the Office of Research and Development. There is a well known need for information on human exposure to thousands of chemicals, especially with respect to route of exposure. A combination of curation of legacy data, new data collection activities, and mathematical models based both upon statistics (empirical) and mechanism are allowing chemicals to be prioritized for further exposure study. This presentation pays special attention to the opportunities presented by non-targeted screening using mass spectrometry. This is a presentation to the American College of Toxicology annual meeting in Baltimore, Maryland on November 7, 2016. This half hour presentation is part of a session on 21st Century Approaches to Assessing Food Ingredient Safety.

  20. Assessment of predictive dermal exposure to chemicals in the work environment

    Directory of Open Access Journals (Sweden)

    Agnieszka Jankowska

    2017-08-01

    Full Text Available Assessment of dermal exposure to chemicals in the work environment is problematic, mainly as a result of the lack of measurement data on occupational exposure to chemicals. Due to common prevalence of occupational skin exposure and its health consequences it is necessary to look for efficient solutions allowing for reliable exposure assessment. The aim of the study is to present predictive models used to assess non-measured dermal exposure, as well as to acquaint Polish users with the principles of the selected model functioning. This paper presents examples of models to assist the employer in the the assessment of occupational exposure associated with the skin contact with chemicals, developed in European Union (EU countries, as well as in countries outside the EU. Based on the literature data dermal exposure models EASE (Estimation and Assessment of Substance Exposure, COSHH Essentials (Control of Substances Hazardous to Health Regulations, DREAM (Dermal Exposure Assessment Method, Stoffenmanager , ECETOC TRA (European Centre for Ecotoxicology and Toxicology of Chemicals Targeted Risk Assessment, MEASE (Metal’s EASE, PHED (Pesticide Handlers Exposure Database, DERM (Dermal Exposure Ranking Method and RISKOFDERM (Risk Assessment of Occupational Dermal Exposure to Chemicals were briefly described. Moreover the characteristics of RISKOFDERM, guidelines for its use, information on input and output data were further detailed. Problem of full work shift dermal exposure assessment is described. An example of exposure assessment using RISKOFDERM and effectiveness evaluation to date were also presented. When no measurements are available, RISKOFDERM allows dermal exposure assessment and thus can improve the risk assessment quality and effectiveness of dermal risk management. Med Pr 2017;68(4:557–569

  1. In Vitro Exposure Systems and Dosimetry Assessment Tools ...

    Science.gov (United States)

    In 2009, the passing of The Family Smoking Prevention and Tobacco Control Act facilitated the establishment of the FDA Center for Tobacco Products (CTP) and gave it regulatory authority over the marketing, manufacture and distribution of tobacco products, including those termed “modified risk”. On 4-6 April 2016, the Institute for In Vitro Sciences, Inc. (IIVS) convened a workshop conference titled “In Vitro Exposure Systems and Dosimetry Assessment Tools for Inhaled Tobacco Products” to bring together stakeholders representing regulatory agencies, academia, and industry to address the research priorities articulated by the FDA CTP. Specific topics were covered to assess the status of current in vitro smoke and aerosol/vapor exposure systems, as well as the various approaches and challenges to quantifying the complex exposures, in in vitro pulmonary models developed for evaluating adverse pulmonary events resulting from tobacco product exposures. The four core topics covered were, 1) Tobacco Smoke And E-Cigarette Aerosols, 2) Air-Liquid Interface-In Vitro Exposure Systems, 3) Dosimetry Approaches For Particles And Vapors; In Vitro Dosimetry Determinations and 4) Exposure Microenvironment/Physiology Of Cells. The two and a half day workshop included presentations from 20 expert speakers, poster sessions, networking discussions, and breakout sessions which identified key findings and provided recommendations to advance these technologies. Here, we will re

  2. Validation of the dermal exposure model in ECETOC TRA.

    Science.gov (United States)

    Marquart, Hans; Franken, Remy; Goede, Henk; Fransman, Wouter; Schinkel, Jody

    2017-08-01

    The ECETOC TRA model (presently version 3.1) is often used to estimate worker inhalation and dermal exposure in regulatory risk assessment. The dermal model in ECETOC TRA has not yet been validated by comparison with independent measured exposure levels. This was the goal of the present study. Measured exposure levels and relevant contextual information were gathered via literature search, websites of relevant occupational health institutes and direct requests for data to industry. Exposure data were clustered in so-called exposure cases, which are sets of data from one data source that are expected to have the same values for input parameters in the ECETOC TRA dermal exposure model. For each exposure case, the 75th percentile of measured values was calculated, because the model intends to estimate these values. The input values for the parameters in ECETOC TRA were assigned by an expert elicitation and consensus building process, based on descriptions of relevant contextual information.From more than 35 data sources, 106 useful exposure cases were derived, that were used for direct comparison with the model estimates. The exposure cases covered a large part of the ECETOC TRA dermal exposure model. The model explained 37% of the variance in the 75th percentiles of measured values. In around 80% of the exposure cases, the model estimate was higher than the 75th percentile of measured values. In the remaining exposure cases, the model estimate may not be sufficiently conservative.The model was shown to have a clear bias towards (severe) overestimation of dermal exposure at low measured exposure values, while all cases of apparent underestimation by the ECETOC TRA dermal exposure model occurred at high measured exposure values. This can be partly explained by a built-in bias in the effect of concentration of substance in product used, duration of exposure and the use of protective gloves in the model. The effect of protective gloves was calculated to be on average a

  3. Technical Overview of Ecological Risk Assessment - Analysis Phase: Exposure Characterization

    Science.gov (United States)

    Exposure Characterization is the second major component of the analysis phase of a risk assessment. For a pesticide risk assessment, the exposure characterization describes the potential or actual contact of a pesticide with a plant, animal, or media.

  4. Use-exposure relationships of pesticides for aquatic risk assessment.

    Directory of Open Access Journals (Sweden)

    Yuzhou Luo

    2011-04-01

    Full Text Available Field-scale environmental models have been widely used in aquatic exposure assessments of pesticides. Those models usually require a large set of input parameters and separate simulations for each pesticide in evaluation. In this study, a simple use-exposure relationship is developed based on regression analysis of stochastic simulation results generated from the Pesticide Root-Zone Model (PRZM. The developed mathematical relationship estimates edge-of-field peak concentrations of pesticides from aerobic soil metabolism half-life (AERO, organic carbon-normalized soil sorption coefficient (KOC, and application rate (RATE. In a case study of California crop scenarios, the relationships explained 90-95% of the variances in the peak concentrations of dissolved pesticides as predicted by PRZM simulations for a 30-year period. KOC was identified as the governing parameter in determining the relative magnitudes of pesticide exposures in a given crop scenario. The results of model application also indicated that the effects of chemical fate processes such as partitioning and degradation on pesticide exposure were similar among crop scenarios, while the cross-scenario variations were mainly associated with the landscape characteristics, such as organic carbon contents and curve numbers. With a minimum set of input data, the use-exposure relationships proposed in this study could be used in screening procedures for potential water quality impacts from the off-site movement of pesticides.

  5. Exposure assessment in studies on health effects of traffic exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Setaelae, S [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J J.K. [Helsinki Univ. (Finland). Dept. of Public Health

    1996-12-31

    A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

  6. Exposure assessment in studies on health effects of traffic exhaust

    Energy Technology Data Exchange (ETDEWEB)

    Setaelae, S. [Association for the Pulmonary Disabled, Helsinki (Finland); Jaakkola, J.J.K. [Helsinki Univ. (Finland). Dept. of Public Health

    1995-12-31

    A main source of outdoor air pollution is road traffic, which produces a complex mixture of nitrogen oxides, carbon monoxide, volatile hydrocarbons, airborne particles and some other compounds. Traffic exhaust affects also the concentrations of ozone and other photo chemical oxidants. In earlier studies those components have had remarkable health effects. Several studies on occupational exposure to automobile exhaust have been published and several studies have been observed an association between both outdoor and indoor pollutant levels and health outcomes. However, there are only a few epidemiological studies in which traffic exhaust, a complex mixture, has been studied in its entirety. During recent years, interesting epidemiological studies of the health effects of this complex mixture have been published. Human exposure assessment for traffic exhaust can be categorized according to the environment of exposure (indoors, outdoors, in-traffic) or to the method of exposure assessment (direct or indirect methods). In this presentation the methods are further categorized into (1) traffic activity, (2) air concentration measurements, and (3) dispersion models, in order to better understand the advantages and disadvantages of different approaches. The objective of this presentation is to make a critical review of exposure assessments in the epidemiological studies on health effects of traffic exhaust. (author)

  7. Environmental radiation exposure: Regulation, monitoring, and assessment

    International Nuclear Information System (INIS)

    Chen, S.Y.; Yu, C.; Hong, K.J.

    1991-01-01

    Radioactive releases to the environment from nuclear facilities constitute a public health concern. Protecting the public from such releases can be achieved through the establishment and enforcement of regulatory standards. In the United States, numerous standards have been promulgated to regulate release control at nuclear facilities. Most recent standards are more restrictive than those in the past and require that radioactivity levels be as low as reasonably achievable (ALARA). Environmental monitoring programs and radiological dose assessment are means of ensuring compliance with regulations. Environmental monitoring programs provide empirical information on releases, such as the concentrations of released radioactivity in environmental media, while radiological dose assessment provides the analytical means of quantifying dose exposures for demonstrating compliance

  8. Presenting of a material exposure health risk assessment model in Oil and Gas Industries (case study: Pars Economic and Energy Region)

    OpenAIRE

    M. Heydari; M. Omidvari; I. M. Fam

    2014-01-01

    Introduction: One of the most important threats for employees working in chemical industries is exposing to the chemical materials. Lack of precaution and control regulations during working with chemicals can have irreparable consequences. So, in order to achieve an effective control program, it is necessary to have an appropriate assessment of the procedures involving exposure to the chemicals. William-fine method can provide an acceptable insight into hazard risk rate. . Material...

  9. How to assess exposure of aquatic organisms to manufactured nanoparticles?

    DEFF Research Database (Denmark)

    Quik, Joris T.K.; Vonk, Jan Arie; Hansen, Steffen Foss

    2011-01-01

    Ecological risk of chemicals is measured by the quotient of predicted no-effect concentrations and predicted exposure concentrations, which are hard to assess for manufactured nanomaterials (NMs). This paper proposes modifications to currently used models, in order to make them suitable for estim......Ecological risk of chemicals is measured by the quotient of predicted no-effect concentrations and predicted exposure concentrations, which are hard to assess for manufactured nanomaterials (NMs). This paper proposes modifications to currently used models, in order to make them suitable...... on sedimentation and dissolution of NMs in environmentally relevant systems. We deduce that the overall kinetics of water–sediment transport of NMs should be close to first order. The lack of data on dissolution of NMs under environmentally realistic conditions calls for a pragmatic decision on which rates...

  10. Assessment of human exposure to environmental sources of nickel in Europe: Inhalation exposure.

    Science.gov (United States)

    Buekers, Jurgen; De Brouwere, Katleen; Lefebvre, Wouter; Willems, Hanny; Vandenbroele, Marleen; Van Sprang, Patrick; Eliat-Eliat, Maxime; Hicks, Keegan; Schlekat, Christian E; Oller, Adriana R

    2015-07-15

    The paper describes the inhalation nickel (Ni) exposure of humans via the environment for the regional scale in the EU, together with a tiered approach for assessing additional local exposure from industrial emissions. The approach was designed, in the context of REACH, for the purpose of assessing and controlling emissions and air quality in the neighbourhood of Ni producers and downstream users. Two Derived No Effect Level (DNEL) values for chronic inhalation exposure to total Ni in PM10 (20 and 60ngNi/m(3)) were considered. The value of 20ngNi/m(3) is the current EU air quality guidance value. The value of 60ngNi/m(3) is derived here based on recently published Ni data (Oller et al., 2014). Both values are protective for respiratory toxicity and carcinogenicity but differ in the application of toxicokinetic adjustments and cancer threshold considerations. Estimates of air Ni concentrations at the European regional scale were derived from the database of the European Environment Agency. The 50th and 90th percentile regional exposures were below both DNEL values. To assess REACH compliance at the local scale, measured ambient air data are preferred but are often unavailable. A tiered approach for the use of modelled ambient air concentrations was developed, starting with the application of the default EUSES model and progressing to more sophisticated models. As an example, the tiered approach was applied to 33 EU Ni sulphate producers' and downstream users' sites. Applying the EUSES model demonstrates compliance with a DNEL of 60ngNi/m(3) for the majority of sites, while the value of the refined modelling is demonstrated when a DNEL of 20ngNi/m(3) is considered. The proposed approach, applicable to metals in general, can be used in the context of REACH, for refining the risk characterisation and guiding the selection of risk management measures. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. Health impact assessment of air pollution using a dynamic exposure profile: Implications for exposure and health impact estimates

    International Nuclear Information System (INIS)

    Dhondt, Stijn; Beckx, Carolien; Degraeuwe, Bart; Lefebvre, Wouter; Kochan, Bruno; Bellemans, Tom; Int Panis, Luc; Macharis, Cathy; Putman, Koen

    2012-01-01

    In both ambient air pollution epidemiology and health impact assessment an accurate assessment of the population exposure is crucial. Although considerable advances have been made in assessing human exposure outdoors, the assessments often do not consider the impact of individual travel behavior on such exposures. Population-based exposures to NO 2 and O 3 using only home addresses were compared with models that integrate all time-activity patterns—including time in commute—for Flanders and Brussels. The exposure estimates were used to estimate the air pollution impact on years of life lost due to respiratory mortality. Health impact of NO 2 using an exposure that integrates time-activity information was on average 1.2% higher than when assuming that people are always at their home address. For ozone the overall estimated health impact was 0.8% lower. Local differences could be much larger, with estimates that differ up to 12% from the exposure using residential addresses only. Depending on age and gender, deviations from the population average were seen. Our results showed modest differences on a regional level. At the local level, however, time-activity patterns indicated larger differences in exposure and health impact estimates, mainly for people living in more rural areas. These results suggest that for local analyses the dynamic approach can contribute to an improved assessment of the health impact of various types of pollution and to the understanding of exposure differences between population groups. - Highlights: ► Exposure to ambient air pollution was assessed integrating population mobility. ► This dynamic exposure was integrated into a health impact assessment. ► Differences between the dynamic and residential exposure were quantified. ► Modest differences in health impact were found at a regional level. ► At municipal level larger differences were found, influenced by gender and age.

  12. Health impact assessment of air pollution using a dynamic exposure profile: Implications for exposure and health impact estimates

    Energy Technology Data Exchange (ETDEWEB)

    Dhondt, Stijn, E-mail: stijn.dhondt@vub.ac.be [Department of Medical Sociology and Health Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels (Belgium); Beckx, Carolien, E-mail: Carolien.Beckx@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Degraeuwe, Bart, E-mail: Bart.Degraeuwe@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Lefebvre, Wouter, E-mail: Wouter.Lefebvre@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Kochan, Bruno, E-mail: Bruno.Kochan@uhasselt.be [Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Bellemans, Tom, E-mail: Tom.Bellemans@uhasselt.be [Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Int Panis, Luc, E-mail: Luc.intpanis@vito.be [Flemish Institute for Technological Research (VITO), Boeretang 200, 2400 Mol (Belgium); Transportation Research Institute, Hasselt University, Wetenschapspark 5 bus 6, 3590 Diepenbeek (Belgium); Macharis, Cathy, E-mail: cjmachar@vub.ac.be [Department MOSI-Transport and Logistics, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels (Belgium); Putman, Koen, E-mail: kputman@vub.ac.be [Department of Medical Sociology and Health Sciences, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090, Brussels (Belgium); Interuniversity Centre for Health Economics Research (I-CHER), Vrije Universiteit Brussel, Brussels (Belgium)

    2012-09-15

    In both ambient air pollution epidemiology and health impact assessment an accurate assessment of the population exposure is crucial. Although considerable advances have been made in assessing human exposure outdoors, the assessments often do not consider the impact of individual travel behavior on such exposures. Population-based exposures to NO{sub 2} and O{sub 3} using only home addresses were compared with models that integrate all time-activity patterns-including time in commute-for Flanders and Brussels. The exposure estimates were used to estimate the air pollution impact on years of life lost due to respiratory mortality. Health impact of NO{sub 2} using an exposure that integrates time-activity information was on average 1.2% higher than when assuming that people are always at their home address. For ozone the overall estimated health impact was 0.8% lower. Local differences could be much larger, with estimates that differ up to 12% from the exposure using residential addresses only. Depending on age and gender, deviations from the population average were seen. Our results showed modest differences on a regional level. At the local level, however, time-activity patterns indicated larger differences in exposure and health impact estimates, mainly for people living in more rural areas. These results suggest that for local analyses the dynamic approach can contribute to an improved assessment of the health impact of various types of pollution and to the understanding of exposure differences between population groups. - Highlights: Black-Right-Pointing-Pointer Exposure to ambient air pollution was assessed integrating population mobility. Black-Right-Pointing-Pointer This dynamic exposure was integrated into a health impact assessment. Black-Right-Pointing-Pointer Differences between the dynamic and residential exposure were quantified. Black-Right-Pointing-Pointer Modest differences in health impact were found at a regional level. Black

  13. Development of an in vitro cytotoxicity model for aerosol exposure using 3D reconstructed human airway tissue; application for assessment of e-cigarette aerosol.

    Science.gov (United States)

    Neilson, Louise; Mankus, Courtney; Thorne, David; Jackson, George; DeBay, Jason; Meredith, Clive

    2015-10-01

    Development of physiologically relevant test methods to analyse potential irritant effects to the respiratory tract caused by e-cigarette aerosols is required. This paper reports the method development and optimisation of an acute in vitro MTT cytotoxicity assay using human 3D reconstructed airway tissues and an aerosol exposure system. The EpiAirway™ tissue is a highly differentiated in vitro human airway culture derived from primary human tracheal/bronchial epithelial cells grown at the air-liquid interface, which can be exposed to aerosols generated by the VITROCELL® smoking robot. Method development was supported by understanding the compatibility of these tissues within the VITROCELL® system, in terms of airflow (L/min), vacuum rate (mL/min) and exposure time. Dosimetry tools (QCM) were used to measure deposited mass, to confirm the provision of e-cigarette aerosol to the tissues. EpiAirway™ tissues were exposed to cigarette smoke and aerosol generated from two commercial e-cigarettes for up to 6 h. Cigarette smoke reduced cell viability in a time dependent manner to 12% at 6 h. E-cigarette aerosol showed no such decrease in cell viability and displayed similar results to that of the untreated air controls. Applicability of the EpiAirway™ model and exposure system was demonstrated, showing little cytotoxicity from e-cigarette aerosol and different aerosol formulations when compared directly with reference cigarette smoke, over the same exposure time. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  14. An in vitro assessment of bioaccessibility of arsenicals in rice and the use of this estimate within a probabilistic exposure model.

    Science.gov (United States)

    Trenary, Heather R; Creed, Patricia A; Young, Andrea R; Mantha, Madhavi; Schwegel, Carol A; Xue, Jianping; Kohan, Michael J; Herbin-Davis, Karen; Thomas, David J; Caruso, Joseph A; Creed, John T

    2012-07-01

    In this study, an in vitro synthetic gastrointestinal extraction protocol was used to estimate bioaccessibility of different arsenicals present in 17 rice samples of various grain types that were collected across the United States. The across matrix average for total arsenic was 209 ng/g±153 (\\[xmacr]±2σ). The bioaccessibility estimate produced an across matrix average of 61%±19 (\\[xmacr]±2σ). The across matrix average concentrations of inorganic arsenic (iAs) and dimethylarsinic acid (DMA) were 81 ng/g±67.7 and 41 ng/g±58.1 (\\[xmacr]±2σ), respectively. This distribution of iAs concentrations in rice was combined with the distribution of consumption patterns (from WWEIA) in a Stochastic Human Exposure and Dose Simulator model to estimate population-based exposures. The mean consumption rate for the population as a whole was 15.7 g per day resulting in a 0.98 μg iAs per day exposure. The mean consumption rate for children 1-2 years old was 7 g per day resulting in a 0.48 μg iAs per day exposure. Presystemic biotransformation of DMA in rice was examined using an in vitro assay containing the anaerobic microbiota of mouse cecum. This assay indicated that DMA extracted from the rice was converted to dimethylthioarsinic acid, although a second oxygen-sulfur exchange to produce DMDTA was not observed.

  15. Health effects assessment of chemical exposures: ARIES methodology

    Energy Technology Data Exchange (ETDEWEB)

    Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

    1995-07-01

    In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs.

  16. Health effects assessment of chemical exposures: ARIES methodology

    International Nuclear Information System (INIS)

    Sierra, L; Montero, M.; Rabago, I.; Vidania, R.

    1995-01-01

    In this work, we present ARIES* update: a system designed in order to facilitate the human health effects assessment produced by accidental release of toxic chemicals. The first version of ARIES was developed in relation to 82/501/EEC Directive about mayor accidents in the chemical industry. So, the first aim was the support of the effects assessment derived for the chemicals included into this directive. From this establishment, it was considered acute exposures for high concentrations. In this report, we present the actual methodology for considering other type of exposures, such as environmental and occupational. Likewise other versions, the methodology comprises two approaches: quantitative and qualitative assessments. Quantitative assessment incorporates the mathematical algorithms useful to evaluate the effects produced by the most important routes of exposure: inhalation, ingestion, eye contact and skin absorption, in a short, medium and long term. It has been included models that realizes an accurate quantification of doses, effects,... and so on, such as simple approaches when the available information is not enough. Qualitative assessment, designed in order to complement or replace the previous one, is incorporated into an informatics system, developed in Clipper. It executes and displays outstanding and important toxicological information of about 100 chemicals. This information comes from ECDIN (Environmental Chemicals Data and Information Network) database through a collaboration with JRC-ISPRA working group. (Author) 24 refs

  17. Exposure Assessment Tools by Lifestages and Populations - General Population

    Science.gov (United States)

    EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

  18. [Hygiene and legal aspects of occupational exposure assessment to cytostatics].

    Science.gov (United States)

    Kupczewska-Dobecka, Małgorzata; Pałaszewska-Tkacz, Anna; Czerczak, Sławomir; Konieczko, Katarzyna

    2018-01-01

    The employers responsibilities for the assessment of occupational exposure to cytostatics in the workplace were analyzed in the light of existing legal regulations. Cytostatics may pose a threat to health and life of workers taking care of patients treated oncologically, i.e., pharmacists, physicians, nurses and other personnel. The significant scale of occupational exposure to cytostatics in Poland is confirmed by the data collected in the Central Register of Data on Exposure to Carcinogenic or Mutagenic Substances, Mixtures, Agents or Technological Processes, maintained by the Nofer Institute of Occupational Medicine, Łódź, Poland. The issue of occupational risk assessment of exposure to cytostatics gives raise to numerous concerns. Polish regulations concerning health protection of employees occupationally exposed to cytostatics are not unequivocal, as they are derived from different areas of the law, especially those applying to hazard classification, labeling and preparation of safety data sheets for cytostatics. There are neither binding occupational exposure limits legally set for active compounds of antineoplastic drugs nor methods for monitoring of these substances concentrations in a worker's breathing zone and biological material. This prevents the employer to carry out the correct assessment of occupational exposure, the results of which are the basis for preparing the proper preventive strategy. In this article the consequences of amendments to the European chemical legislation for employers responsible for adequate protection of health and life of employees exposed to cytostatics, were discussed, as well as some legal changes aimed at a better health and life protection of workers exposed to cytostatics in a workplace were proposed. Med Pr 2018;69(1):77-92. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  19. Exploring Global Exposure Factors Resources for Use in Consumer Exposure Assessments

    Science.gov (United States)

    Zaleski, Rosemary T.; Egeghy, Peter P.; Hakkinen, Pertti J.

    2016-01-01

    This publication serves as a global comprehensive resource for readers seeking exposure factor data and information relevant to consumer exposure assessment. It describes the types of information that may be found in various official surveys and online and published resources. The relevant exposure factors cover a broad range, including general exposure factor data found in published compendia and databases and resources about specific exposure factors, such as human activity patterns and housing information. Also included are resources on exposure factors related to specific types of consumer products and the associated patterns of use, such as for a type of personal care product or a type of children’s toy. Further, a section on using exposure factors for designing representative exposure scenarios is included, along with a look into the future for databases and other exposure science developments relevant for consumer exposure assessment. PMID:27455300

  20. Comprehensive European dietary exposure model (CEDEM) for food additives.

    Science.gov (United States)

    Tennant, David R

    2016-05-01

    European methods for assessing dietary exposures to nutrients, additives and other substances in food are limited by the availability of detailed food consumption data for all member states. A proposed comprehensive European dietary exposure model (CEDEM) applies summary data published by the European Food Safety Authority (EFSA) in a deterministic model based on an algorithm from the EFSA intake method for food additives. The proposed approach can predict estimates of food additive exposure provided in previous EFSA scientific opinions that were based on the full European food consumption database.

  1. Assessing human variability in kinetics for exposures to multiple environmental chemicals: a physiologically based pharmacokinetic modeling case study with dichloromethane, benzene, toluene, ethylbenzene, and m-xylene.

    Science.gov (United States)

    Valcke, Mathieu; Haddad, Sami

    2015-01-01

    The objective of this study was to compare the magnitude of interindividual variability in internal dose for inhalation exposure to single versus multiple chemicals. Physiologically based pharmacokinetic models for adults (AD), neonates (NEO), toddlers (TODD), and pregnant women (PW) were used to simulate inhalation exposure to "low" (RfC-like) or "high" (AEGL-like) air concentrations of benzene (Bz) or dichloromethane (DCM), along with various levels of toluene alone or toluene with ethylbenzene and xylene. Monte Carlo simulations were performed and distributions of relevant internal dose metrics of either Bz or DCM were computed. Area under the blood concentration of parent compound versus time curve (AUC)-based variability in AD, TODD, and PW rose for Bz when concomitant "low" exposure to mixtures of increasing complexities occurred (coefficient of variation (CV) = 16-24%, vs. 12-15% for Bz alone), but remained unchanged considering DCM. Conversely, AUC-based CV in NEO fell (15 to 5% for Bz; 12 to 6% for DCM). Comparable trends were observed considering production of metabolites (AMET), except for NEO's CYP2E1-mediated metabolites of Bz, where an increased CV was observed (20 to 71%). For "high" exposure scenarios, Cmax-based variability of Bz and DCM remained unchanged in AD and PW, but decreased in NEO (CV= 11-16% to 2-6%) and TODD (CV= 12-13% to 7-9%). Conversely, AMET-based variability for both substrates rose in every subpopulation. This study analyzed for the first time the impact of multiple exposures on interindividual variability in toxicokinetics. Evidence indicates that this impact depends upon chemical concentrations and biochemical properties, as well as the subpopulation and internal dose metrics considered.

  2. INFLUENCE OF EXPOSURE ASSESSMENT METHOD IN AN EPIDEMIOLOGIC STUDY OF TRIHALOMETHANE EXPOSURE AND SPONTANEOUS ABORTION

    Science.gov (United States)

    Trihalomethanes are common contaminants of chlorinated drinking water. Studies of their health effects have been hampered by exposure misclassification, due in part to limitations inherent in using utility sampling records. We used two exposure assessment methods, one based on ut...

  3. An in vitro liver model--assessing oxidative stress and genotoxicity following exposure of hepatocytes to a panel of engineered nanomaterials

    DEFF Research Database (Denmark)

    Kermanizadeh, Ali; Gaiser, Birgit K; Hutchison, Gary R

    2012-01-01

    Following exposure via inhalation, intratracheal instillation or ingestion some nanomaterials (NM) have been shown to translocate to the liver. Since oxidative stress has been implicated as a possible mechanism for NM toxicity this study aimed to investigate the effects of various materials (five...... titanium dioxide (TiO2), two zinc oxide (ZnO), two multi-walled carbon nanotubes (MWCNT) and one silver (Ag) NM) on oxidative responses of C3A cell line as a model for potential detrimental properties of nanomaterials on the liver.......Following exposure via inhalation, intratracheal instillation or ingestion some nanomaterials (NM) have been shown to translocate to the liver. Since oxidative stress has been implicated as a possible mechanism for NM toxicity this study aimed to investigate the effects of various materials (five...

  4. A statistical framework for the validation of a population exposure model based on personal exposure data

    Science.gov (United States)

    Rodriguez, Delphy; Valari, Myrto; Markakis, Konstantinos; Payan, Sébastien

    2016-04-01

    Currently, ambient pollutant concentrations at monitoring sites are routinely measured by local networks, such as AIRPARIF in Paris, France. Pollutant concentration fields are also simulated with regional-scale chemistry transport models such as CHIMERE (http://www.lmd.polytechnique.fr/chimere) under air-quality forecasting platforms (e.g. Prev'Air http://www.prevair.org) or research projects. These data may be combined with more or less sophisticated techniques to provide a fairly good representation of pollutant concentration spatial gradients over urban areas. Here we focus on human exposure to atmospheric contaminants. Based on census data on population dynamics and demographics, modeled outdoor concentrations and infiltration of outdoor air-pollution indoors we have developed a population exposure model for ozone and PM2.5. A critical challenge in the field of population exposure modeling is model validation since personal exposure data are expensive and therefore, rare. However, recent research has made low cost mobile sensors fairly common and therefore personal exposure data should become more and more accessible. In view of planned cohort field-campaigns where such data will be available over the Paris region, we propose in the present study a statistical framework that makes the comparison between modeled and measured exposures meaningful. Our ultimate goal is to evaluate the exposure model by comparing modeled exposures to monitor data. The scientific question we address here is how to downscale modeled data that are estimated on the county population scale at the individual scale which is appropriate to the available measurements. To assess this question we developed a Bayesian hierarchical framework that assimilates actual individual data into population statistics and updates the probability estimate.

  5. An approach to assess the Particulate Matter exposure for the population living around a cement plant: modelling indoor air and particle deposition in the respiratory tract

    Energy Technology Data Exchange (ETDEWEB)

    Sánchez-Soberón, Francisco; Mari, Montse; Kumar, Vikas [Environmental Engineering Laboratory, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia (Spain); Rovira, Joaquim [Environmental Engineering Laboratory, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia (Spain); Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Catalonia (Spain); Nadal, Martí [Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Catalonia (Spain); Schuhmacher, Marta, E-mail: marta.schuhmacher@urv.cat [Environmental Engineering Laboratory, Departament d' Enginyeria Quimica, Universitat Rovira i Virgili, Av. Països Catalans 26, 43007 Tarragona, Catalonia (Spain); Laboratory of Toxicology and Environmental Health, School of Medicine, IISPV, Universitat Rovira i Virgili, Sant Llorenç 21, 43201 Reus, Catalonia (Spain)

    2015-11-15

    In this paper we studied the exposure to three size fractions of outdoor particulate matter (PM{sub 10}, PM{sub 2.5}, and PM{sub 1}) collected in an area influenced by a cement plant. For that purpose, three groups of population were evaluated (children, adults and retired) in two seasons (summer and winter). Outdoor measured PM concentrations, as well as physiological parameters and activity patterns of the three groups of population were used as input data in two different models. The first one was an indoor air quality model, used to elucidate indoor PM concentrations in different microenvironments. The second one was a dosimetry model, used to evaluate the internal exposure and the distribution of the different PM fractions in the respiratory tract. Results from the indoor air quality model showed that special attention must be paid to the finest particles, since they penetrate indoors in a greater degree. Highest pulmonary doses for the three PM sizes were reported for retired people, being this a result of the high amount of time in outdoor environments exercising lightly. For children, the exposure was mainly influenced by the time they also spend outdoors, but in this case due to heavy intensity activities. It was noticed that deposition of fine particles was more significant in the pulmonary regions of children and retired people in comparison with adults, which has implications in the expected adverse health effects for those vulnerable groups of population. - Highlights: • PM deposition in the respiratory tract was evaluated for three population groups. • Activity patterns and different microenvironments were used in our calculation. • Outdoor activities are the main contributors to PM deposited mass. • Children experienced the highest deposition dose in the pulmonary region. • Retired registered the highest deposited mass in the respiratory tract as a whole.

  6. An approach to assess the Particulate Matter exposure for the population living around a cement plant: modelling indoor air and particle deposition in the respiratory tract

    International Nuclear Information System (INIS)

    Sánchez-Soberón, Francisco; Mari, Montse; Kumar, Vikas; Rovira, Joaquim; Nadal, Martí; Schuhmacher, Marta

    2015-01-01

    In this paper we studied the exposure to three size fractions of outdoor particulate matter (PM 10 , PM 2.5 , and PM 1 ) collected in an area influenced by a cement plant. For that purpose, three groups of population were evaluated (children, adults and retired) in two seasons (summer and winter). Outdoor measured PM concentrations, as well as physiological parameters and activity patterns of the three groups of population were used as input data in two different models. The first one was an indoor air quality model, used to elucidate indoor PM concentrations in different microenvironments. The second one was a dosimetry model, used to evaluate the internal exposure and the distribution of the different PM fractions in the respiratory tract. Results from the indoor air quality model showed that special attention must be paid to the finest particles, since they penetrate indoors in a greater degree. Highest pulmonary doses for the three PM sizes were reported for retired people, being this a result of the high amount of time in outdoor environments exercising lightly. For children, the exposure was mainly influenced by the time they also spend outdoors, but in this case due to heavy intensity activities. It was noticed that deposition of fine particles was more significant in the pulmonary regions of children and retired people in comparison with adults, which has implications in the expected adverse health effects for those vulnerable groups of population. - Highlights: • PM deposition in the respiratory tract was evaluated for three population groups. • Activity patterns and different microenvironments were used in our calculation. • Outdoor activities are the main contributors to PM deposited mass. • Children experienced the highest deposition dose in the pulmonary region. • Retired registered the highest deposited mass in the respiratory tract as a whole.

  7. Methyldibromo glutaronitrile: clinical experience and exposure-based risk assessment.

    Science.gov (United States)

    Zachariae, Claus; Rastogi, Suresh; Devantier, Charlotte; Menné, Torkil; Johansen, Jeanne Duus

    2003-03-01

    In the year 2000, the level of methyldibromo glutaronitrile (MDGN) allergy in dermatology clinics in Europe exceeded the level of allergies to all other preservatives, with a prevalence of 3.5%. In the present study, cases of primary sensitization and elicitation to MDGN due to cosmetic products were collected over an 8-month period at the Department of Dermatology, Gentofte University Hospital. The aim was to identify the products related to hand eczema, assess exposure to MDGN in these products and relate the findings to results from a newly developed updated risk assessment model for contact allergy. Out of 24 patients with a positive patch test to MDGN, 17 patients with hand eczema were identified. In 11 of these patients, cosmetic products used in relation to the onset of the disease were shown to contain MDGN (65%). In 8 of these 11 cases, primary sensitization was probable, 5 due to hand/body lotions and 3 due to lotions and/or liquid hand soap. Chemical analysis of 12 products showed that lotions contained 149-390 ppm of MDGN, liquid hand soap 144-399 ppm, a rinsing cream 293 ppm and shampoos 78-79 ppm. The shampoo exposure was not of certain relevance to the eczema. Applying the newly developed updated risk assessment model showed that the concentrations of MDGN in lotions of 149-390 ppm exceeded the calculated maximum acceptable exposure level for MDGN, which would be expected to lead to sensitization in consumers using such products, as seen in the current study. The present cases and updated exposure-based risk assessment process add to the evidence and need for re-defining safe-use concentrations of MDGN in cosmetic products.

  8. Quantifying human exposure to air pollution - moving from static monitoring to spatio-temporally resolved personal exposure assessment

    DEFF Research Database (Denmark)

    Steinle, Susanne; Reis, Stefan; Sabel, Clive E

    2013-01-01

    exposure studies to accurately assess human health risks. ? We discuss potential and shortcomings of methods and tools with a focus on how their development influences study design. ? We propose a novel conceptual model for integrated health impact assessment of human exposure to air pollutants. ? We......Quantifying human exposure to air pollutants is a challenging task. Ambient concentrations of air pollutants at potentially harmful levels are ubiquitous in urban areas and subject to high spatial and temporal variability. At the same time, every individual has unique activity-patterns. Exposure...... results from multifaceted relationships and interactions between environmental and human systems, adding complexity to the assessment process. Traditionally, approaches to quantify human exposure have relied on pollutant concentrations from fixed air quality network sites and static population...

  9. Historical Exposures to Chemicals at the Rocky Flats Nuclear Weapons Plant: A Pilot Retrospective Exposure Assessment

    Energy Technology Data Exchange (ETDEWEB)

    Robertson, Janeen Denise [Univ. of New Mexico, Albuquerque, NM (United States)

    1999-02-01

    In a mortality study of white males who had worked at the Rocky Flats Nuclear Weapons Plant between 1952 and 1979, an increased number of deaths from benign and unspecified intracranial neoplasms was found. A case-control study nested within this cohort investigated the hypothesis that an association existed between brain tumor death and exposure to either internally deposited plutonium or external ionizing radiation. There was no statistically significant association found between estimated radiation exposure from internally deposited plutonium and the development of brain tumors. Exposure by job or work area showed no significant difference between the cohort and the control groups. An update of the study found elevated risk estimates for (1) all lymphopoietic neoplasms, and (2) all causes of death in employees with body burdens greater than or equal to two nanocuries of plutonium. There was an excess of brain tumors for the entire cohort. Similar cohort studies conducted on worker populations from other plutonium handling facilities have not yet shown any elevated risks for brain tumors. Historically, the Rocky Flats Nuclear Weapons Plant used large quantities of chemicals in their production operations. The use of solvents, particularly carbon tetrachloride, was unique to Rocky Flats. No investigation of the possible confounding effects of chemical exposures was done in the initial studies. The objectives of the present study are to (1) investigate the history of chemical use at the Rocky Flats facility; (2) locate and analyze chemical monitoring information in order to assess employee exposure to the chemicals that were used in the highest volume; and (3) determine the feasibility of establishing a chemical exposure assessment model that could be used in future epidemiology studies.

  10. Radiation exposure and risk assessment for critical female body organs

    International Nuclear Information System (INIS)

    Atwell, W.; Weyland, M.D.; Hardy, A.C.

    1991-07-01

    Space radiation exposure limits for astronauts are based on recommendations of the National Council on Radiation Protection and Measurements. These limits now include the age at exposure and sex of the astronaut. A recently-developed computerized anatomical female (CAF) model is discussed in detail. Computer-generated, cross-sectional data are presented to illustrate the completeness of the CAF model. By applying ray-tracing techniques, shield distribution functions have been computed to calculate absorbed dose and dose equivalent values for a variety of critical body organs (e.g., breasts, lungs, thyroid gland, etc.) and mission scenarios. Specific risk assessments, i.e., cancer induction and mortality, are reviewed. 13 refs

  11. Modelling of individual subject ozone exposure response kinetics.

    Science.gov (United States)

    Schelegle, Edward S; Adams, William C; Walby, William F; Marion, M Susan

    2012-06-01

    A better understanding of individual subject ozone (O(3)) exposure response kinetics will provide insight into how to improve models used in the risk assessment of ambient ozone exposure. To develop a simple two compartment exposure-response model that describes individual subject decrements in forced expiratory volume in one second (FEV(1)) induced by the acute inhalation of O(3) lasting up to 8 h. FEV(1) measurements of 220 subjects who participated in 14 previously completed studies were fit to the model using both particle swarm and nonlinear least squares optimization techniques to identify three subject-specific coefficients producing minimum "global" and local errors, respectively. Observed and predicted decrements in FEV(1) of the 220 subjects were used for validation of the model. Further validation was provided by comparing the observed O(3)-induced FEV(1) decrements in an additional eight studies with predicted values obtained using model coefficients estimated from the 220 subjects used in cross validation. Overall the individual subject measured and modeled FEV(1) decrements were highly correlated (mean R(2) of 0.69 ± 0.24). In addition, it was shown that a matrix of individual subject model coefficients can be used to predict the mean and variance of group decrements in FEV(1). This modeling approach provides insight into individual subject O(3) exposure response kinetics and provides a potential starting point for improving the risk assessment of environmental O(3) exposure.

  12. Underwater Sound Propagation Modeling Methods for Predicting Marine Animal Exposure.

    Science.gov (United States)

    Hamm, Craig A; McCammon, Diana F; Taillefer, Martin L

    2016-01-01

    The offshore exploration and production (E&P) industry requires comprehensive and accurate ocean acoustic models for determining the exposure of marine life to the high levels of sound used in seismic surveys and other E&P activities. This paper reviews the types of acoustic models most useful for predicting the propagation of undersea noise sources and describes current exposure models. The severe problems caused by model sensitivity to the uncertainty in the environment are highlighted to support the conclusion that it is vital that risk assessments include transmission loss estimates with statistical measures of confidence.

  13. Modelling survival: exposure pattern, species sensitivity and uncertainty.

    Science.gov (United States)

    Ashauer, Roman; Albert, Carlo; Augustine, Starrlight; Cedergreen, Nina; Charles, Sandrine; Ducrot, Virginie; Focks, Andreas; Gabsi, Faten; Gergs, André; Goussen, Benoit; Jager, Tjalling; Kramer, Nynke I; Nyman, Anna-Maija; Poulsen, Veronique; Reichenberger, Stefan; Schäfer, Ralf B; Van den Brink, Paul J; Veltman, Karin; Vogel, Sören; Zimmer, Elke I; Preuss, Thomas G

    2016-07-06

    The General Unified Threshold model for Survival (GUTS) integrates previously published toxicokinetic-toxicodynamic models and estimates survival with explicitly defined assumptions. Importantly, GUTS accounts for time-variable exposure to the stressor. We performed three studies to test the ability of GUTS to predict survival of aquatic organisms across different pesticide exposure patterns, time scales and species. Firstly, using synthetic data, we identified experimental data requirements which allow for the estimation of all parameters of the GUTS proper model. Secondly, we assessed how well GUTS, calibrated with short-term survival data of Gammarus pulex exposed to four pesticides, can forecast effects of longer-term pulsed exposures. Thirdly, we tested the ability of GUTS to estimate 14-day median effect concentrations of malathion for a range of species and use these estimates to build species sensitivity distributions for different exposure patterns. We find that GUTS adequately predicts survival across exposure patterns that vary over time. When toxicity is assessed for time-variable concentrations species may differ in their responses depending on the exposure profile. This can result in different species sensitivity rankings and safe levels. The interplay of exposure pattern and species sensitivity deserves systematic investigation in order to better understand how organisms respond to stress, including humans.

  14. Risk assessment of exposure to radon decay products

    Energy Technology Data Exchange (ETDEWEB)

    Monchaux, G

    1999-07-01

    The aim of this project was to assess the risk due to inhalation of radon and its decay products using an horizontal approach across a large scale research programme. The central objective was the assessment of human risk which requires combination of several topics involving a multidisciplinary approach. In the Aerosol Studies Group, progress was achieved in improvement, calibration and automation of experimental techniques for continuous and integrated measurements of the unattached fraction f{sub p}- and equilibrium factor F- values. Measurements were performed to determine the variation of size distributions of unattached and aerosol-associated radon decay products under typical living conditions. All aerosol groups performed controlled chamber studies to understand the basic behaviour of airborne activity concentrations. Measurements were performed to determine neutralisation rates of {sup 218}Po, to understand the cluster growth with residence time and to understand the hygroscopic growth of aerosol particles. In the Modelling Group, the programme RADEP has been developed to calculate the weighted committed equivalent lung dose per unit exposure of radon progeny (H{sub w}/P{sub p}) which implements the ICRP Publication 66 Human Respiratory Tract Model (HRTM). The stochastic deposition model (IDEAL) has been compared with the deposition model used by the HRTM, and the agreement between the two deposition models was excellent. A deterministic radon progeny dosimetry model (RADOS) has been developed. This model includes all bronchial airway generations compared with the HRTM that groups the 16 airway generations into three regions. Initial calculations with RADOS show that the basal and secretory cell doses are slightly smaller compared with that of the HRTM. A sensitivity analysis has been performed that has identified those HRTM model parameters that most affect the Hw/Pp. A stochastic rat deposition model (RALMO) and a clearance model for the rat based on the

  15. Risk assessment of exposure to radon decay products

    International Nuclear Information System (INIS)

    Monchaux, G.

    1999-01-01

    The aim of this project was to assess the risk due to inhalation of radon and its decay products using an horizontal approach across a large scale research programme. The central objective was the assessment of human risk which requires combination of several topics involving a multidisciplinary approach. In the Aerosol Studies Group, progress was achieved in improvement, calibration and automation of experimental techniques for continuous and integrated measurements of the unattached fraction f p - and equilibrium factor F- values. Measurements were performed to determine the variation of size distributions of unattached and aerosol-associated radon decay products under typical living conditions. All aerosol groups performed controlled chamber studies to understand the basic behaviour of airborne activity concentrations. Measurements were performed to determine neutralisation rates of 218 Po, to understand the cluster growth with residence time and to understand the hygroscopic growth of aerosol particles. In the Modelling Group, the programme RADEP has been developed to calculate the weighted committed equivalent lung dose per unit exposure of radon progeny (H w /P p ) which implements the ICRP Publication 66 Human Respiratory Tract Model (HRTM). The stochastic deposition model (IDEAL) has been compared with the deposition model used by the HRTM, and the agreement between the two deposition models was excellent. A deterministic radon progeny dosimetry model (RADOS) has been developed. This model includes all bronchial airway generations compared with the HRTM that groups the 16 airway generations into three regions. Initial calculations with RADOS show that the basal and secretory cell doses are slightly smaller compared with that of the HRTM. A sensitivity analysis has been performed that has identified those HRTM model parameters that most affect the Hw/Pp. A stochastic rat deposition model (RALMO) and a clearance model for the rat based on the HRTM have been

  16. Probabilistic quantitative microbial risk assessment model of norovirus from wastewater irrigated vegetables in Ghana using genome copies and fecal indicator ratio conversion for estimating exposure dose

    DEFF Research Database (Denmark)

    Owusu-Ansah, Emmanuel de-Graft Johnson; Sampson, Angelina; Amponsah, Samuel K.

    2017-01-01

    physical and environmental factors that might influence the reliability of using indicator organisms in microbial risk assessment. The challenges facing analytical studies on virus enumeration (genome copies or particles) have contributed to the already existing lack of data in QMRA modelling. This study......The need to replace the commonly applied fecal indicator conversions ratio (an assumption of 1:10− 5 virus to fecal indicator organism) in Quantitative Microbial Risk Assessment (QMRA) with models based on quantitative data on the virus of interest has gained prominence due to the different...... attempts to fit a QMRA model to genome copies of norovirus data. The model estimates the risk of norovirus infection from the intake of vegetables irrigated with wastewater from different sources. The results were compared to the results of a corresponding model using the fecal indicator conversion ratio...

  17. CONSEXPO 3.0, consumer exposure and uptake models

    NARCIS (Netherlands)

    Veen MP van; LBM

    2001-01-01

    The report provides a modelling approach to consumer exposure to chemicals, based on mathematical contact, exposure and uptake models. For each route of exposure, a number of exposure and uptake models are included. A general framework joins the exposure and uptake models selected by the user. By

  18. Integrating local urban climate modelling and mobile sensor data for personal exposure assessments in the context of urban heat island effect

    Science.gov (United States)

    Ueberham, Maximilian; Hertel, Daniel; Schlink, Uwe

    2017-04-01

    Deeper knowledge about urban climate conditions is getting more important in the context of climate change, urban population growth, urban compaction and continued surface sealing. Especially the urban heat island effect (UHI) is one of the most significant human induced alterations of Earth's surface climate. According to this the appearance frequency of heat waves in cities will increase with deep impacts on personal thermal comfort, human health and local residential quality of citizens. UHI can be very heterogenic within a city and research needs to focus more on the neighborhood scale perspective to get further insights about the heat burden of individuals. However, up to now, few is known about local thermal environmental variances and personal exposure loads. To monitor these processes and the impact on individuals, improved monitoring approaches are crucial, complementing data recorded at conventional fixed stations. Therefore we emphasize the importance of micro-meteorological modelling and mobile measurements to shed new light on the nexus of urban human-climate interactions. Contributing to this research we jointly present the approaches of our two PhD-projects. Firstly we illustrate on the basis of an example site, how local thermal conditions in an urban district can be simulated and predicted by a micro-meteorological model. Secondly we highlight the potentials of personal exposure measurements based on an evaluation of mobile micro-sensing devices (MSDs) and analyze and explain differences between model predictions and mobile records. For the examination of local thermal conditions we calculated ENVI-met simulations within the "Bayerischer Bahnhof" quarter in Leipzig (Saxony, Germany; 51°20', 12°22'). To accomplish the maximum temperature contrasts within the diverse built-up structures we chose a hot summer day (25 Aug 2016) under autochthonous weather conditions. From these simulations we analyzed a UHI effect between the model core (urban area

  19. Environmental exposure assessment in European birth cohorts

    DEFF Research Database (Denmark)

    Gehring, Ulrike; Casas, Maribel; Brunekreef, Bert

    2013-01-01

    of the environmental exposure and health data in these studies was made as part of the ENRIECO (Environmental Health Risks in European Birth Cohorts) project. The focus with regard to exposure was on outdoor air pollution, water contamination, allergens and biological organisms, metals, pesticides, smoking and second...... hand tobacco smoke (SHS), persistent organic pollutants (POPs), noise, radiation, and occupational exposures. The review lists methods and data on environmental exposures in 37 European birth cohort studies. Most data is currently available for smoking and SHS (N=37 cohorts), occupational exposures (N......Environmental exposures during pregnancy and early life may have adverse health effects. Single birth cohort studies often lack statistical power to tease out such effects reliably. To improve the use of existing data and to facilitate collaboration among these studies, an inventory...

  20. Assessment and control of fetal exposure

    International Nuclear Information System (INIS)

    Harty, R.; Swinth, K.L.; Traub, R.J.

    1991-10-01

    The assessment and control of fetal exposure to radiation in the workplace is an issue that is complicated by both biological and political/social ramifications. As a result of the dramatic increase in the number of women employed as radiation workers during the past 10 years, many facilities using radioactive materials have instituted fetal protection programs with special requirements for female radiation workers. It is necessary, however, to ensure that any fetal protection program be developed in such a way as to be nondiscriminatory. A study has been initiated whose purpose is to balance the political/social and the biological ramifications associated with occupational protection of the developing embryo/fetus. Several considerations are involved in properly balancing these factors. These considerations include appropriate methods of declaring the pregnancy, training workers, controlling the dose to the embryo/fetus, measuring and calculating the dose to the embryo/fetus, and recording the pertinent information. Alternative strategies for handling these factors while ensuring maximum protection of the embryo/fetus and the rights and responsibilities of employees and employers are discussed

  1. Human Exposure Model (HEM): A modular, web-based application to characterize near-field chemical exposures and releases

    Science.gov (United States)

    The U.S. EPA’s Chemical Safety and Sustainability research program is developing the Human Exposure Model (HEM) to assess near-field exposures to chemicals that occur in various populations over the entire life cycle of a consumer product. The model will be implemented as a...

  2. Assessment of mankind's exposure through his environment: new tools and aid to decision - Colloquium report

    International Nuclear Information System (INIS)

    Thierry-Mieg, Morgane; Rousset, Marine; Varkados-Lemarechal, Margaret

    2012-01-01

    During this colloquium, the different sessions addressed environmental measurement strategies to assess mankind's exposure, the use and the interpretation of exposure bio-markers, the estimation and reconstruction of exposures (integrated modelling, model-measurement coupling), the organization and motives of dialogue between involved parties. Round tables addressed topics such as: measurement strategies and objectives, bio-availability of soil pollutants, approaches and tools for exposure assessment, new methodological strategies for the assessment of chemical exposure, interpretation of bio-markers, reference toxicological values, interest of bio-monitoring in professional environment, transcriptomic analysis, evolutions in the characterization of genotoxic hazards, a tool for the assessment of the exposure of newborn children to pesticides, and so on

  3. Estimators for longitudinal latent exposure models: examining measurement model assumptions.

    Science.gov (United States)

    Sánchez, Brisa N; Kim, Sehee; Sammel, Mary D

    2017-06-15

    Latent variable (LV) models are increasingly being used in environmental epidemiology as a way to summarize multiple environmental exposures and thus minimize statistical concerns that arise in multiple regression. LV models may be especially useful when multivariate exposures are collected repeatedly over time. LV models can accommodate a variety of assumptions but, at the same time, present the user with many choices for model specification particularly in the case of exposure data collected repeatedly over time. For instance, the user could assume conditional independence of observed exposure biomarkers given the latent exposure and, in the case of longitudinal latent exposure variables, time invariance of the measurement model. Choosing which assumptions to relax is not always straightforward. We were motivated by a study of prenatal lead exposure and mental development, where assumptions of the measurement model for the time-changing longitudinal exposure have appreciable impact on (maximum-likelihood) inferences about the health effects of lead exposure. Although we were not particularly interested in characterizing the change of the LV itself, imposing a longitudinal LV structure on the repeated multivariate exposure measures could result in high efficiency gains for the exposure-disease association. We examine the biases of maximum likelihood estimators when assumptions about the measurement model for the longitudinal latent exposure variable are violated. We adapt existing instrumental variable estimators to the case of longitudinal exposures and propose them as an alternative to estimate the health effects of a time-changing latent predictor. We show that instrumental variable estimators remain unbiased for a wide range of data generating models and have advantages in terms of mean squared error. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

  4. Uncertainties in radioecological assessment models

    International Nuclear Information System (INIS)

    Hoffman, F.O.; Miller, C.W.; Ng, Y.C.

    1983-01-01

    Environmental radiological assessments rely heavily on the use of mathematical models. The predictions of these models are inherently uncertain because models are inexact representations of real systems. The major sources of this uncertainty are related to bias in model formulation and imprecision in parameter estimation. The magnitude of uncertainty is a function of the questions asked of the model and the specific radionuclides and exposure pathways of dominant importance. It is concluded that models developed as research tools should be distinguished from models developed for assessment applications. Furthermore, increased model complexity does not necessarily guarantee increased accuracy. To improve the realism of assessment modeling, stochastic procedures are recommended that translate uncertain parameter estimates into a distribution of predicted values. These procedures also permit the importance of model parameters to be ranked according to their relative contribution to the overall predicted uncertainty. Although confidence in model predictions can be improved through site-specific parameter estimation and increased model validation, health risk factors and internal dosimetry models will probably remain important contributors to the amount of uncertainty that is irreducible. 41 references, 4 figures, 4 tables

  5. ASSESSING HUMAN EXPOSURE TO GRASS POLLEN IN DENMARK

    DEFF Research Database (Denmark)

    Peel, Robert George; Hertel, Ole; Herbert, Rob

    Objectives: Exposure to pollen is typically assessed using data collected at fixed roof-top monitoring stations, which give a general picture of airborne pollen concentrations over a wide region. Actual exposure levels can be obtained through personal exposure monitoring. This is typically done u...

  6. Assessing Children's Exposure to Intimate Partner Violence

    Science.gov (United States)

    Knutson, John F.; Lawrence, Erika; Taber, Sarah M.; Bank, Lew; DeGarmo, David S.

    2009-01-01

    Child exposure to intimate partner violence (IPV) is widely acknowledged as a threat to the psycho-social and academic well-being of children. Unfortunately, as reflected in the literature, the specific link between such exposure and childhood outcomes is ambiguous. Based on a review of the literature, this article suggests that this state of…

  7. Media Exposure: How Models Simplify Sampling

    DEFF Research Database (Denmark)

    Mortensen, Peter Stendahl

    1998-01-01

    In media planning, the distribution of exposures to more ad spots in more media (print, TV, radio) is crucial to the evaluation of the campaign. If such information should be sampled, it would only be possible in expensive panel-studies (eg TV-meter panels). Alternatively, the distribution...... of exposures may be modelled statistically, using the Beta distribution combined with the Binomial Distribution. Examples are given....

  8. Assessment of health risks from exposure to ionizing radiation

    International Nuclear Information System (INIS)

    Beebe, G.W.

    1982-01-01

    Rapid development in the assessment of health risks from exposure to ionizing radiation has produced an impressive array of risk differentials of presumed biologic significance. In the human data these differentials involve: (1) the variety of cancer, especially its size; (2) host factors, especially age; (3) time following exposure; (4) magnitude of dose; and (5) type of radiation. From experimental work we may presume that dose-rate also plays a role, especially for sparsely ionizing radiation. Current research is extending the scope of differentials with respect to these and other variables, including cell type and concomitant environmental risk factors, and testing dose-response models suggested by experimental and theoretical work. As facts to be explained, differentials in risk may lead to hypotheses to be explored experimentally and improve our understanding of how ionizing radiation causes cancer. 74 references

  9. Prioritizing Chemicals and Data Requirements for Screening-Level Exposure and Risk Assessment

    Science.gov (United States)

    Brown, Trevor N.; Wania, Frank; Breivik, Knut; McLachlan, Michael S.

    2012-01-01

    Background: Scientists and regulatory agencies strive to identify chemicals that may cause harmful effects to humans and the environment; however, prioritization is challenging because of the large number of chemicals requiring evaluation and limited data and resources. Objectives: We aimed to prioritize chemicals for exposure and exposure potential and obtain a quantitative perspective on research needs to better address uncertainty in screening assessments. Methods: We used a multimedia mass balance model to prioritize > 12,000 organic chemicals using four far-field human exposure metrics. The propagation of variance (uncertainty) in key chemical information used as model input for calculating exposure metrics was quantified. Results: Modeled human concentrations and intake rates span approximately 17 and 15 orders of magnitude, respectively. Estimates of exposure potential using human concentrations and a unit emission rate span approximately 13 orders of magnitude, and intake fractions span 7 orders of magnitude. The actual chemical emission rate contributes the greatest variance (uncertainty) in exposure estimates. The human biotransformation half-life is the second greatest source of uncertainty in estimated concentrations. In general, biotransformation and biodegradation half-lives are greater sources of uncertainty in modeled exposure and exposure potential than chemical partition coefficients. Conclusions: Mechanistic exposure modeling is suitable for screening and prioritizing large numbers of chemicals. By including uncertainty analysis and uncertainty in chemical information in the exposure estimates, these methods can help identify and address the important sources of uncertainty in human exposure and risk assessment in a systematic manner. PMID:23008278

  10. Prioritizing chemicals and data requirements for screening-level exposure and risk assessment.

    Science.gov (United States)

    Arnot, Jon A; Brown, Trevor N; Wania, Frank; Breivik, Knut; McLachlan, Michael S

    2012-11-01

    Scientists and regulatory agencies strive to identify chemicals that may cause harmful effects to humans and the environment; however, prioritization is challenging because of the large number of chemicals requiring evaluation and limited data and resources. We aimed to prioritize chemicals for exposure and exposure potential and obtain a quantitative perspective on research needs to better address uncertainty in screening assessments. We used a multimedia mass balance model to prioritize > 12,000 organic chemicals using four far-field human exposure metrics. The propagation of variance (uncertainty) in key chemical information used as model input for calculating exposure metrics was quantified. Modeled human concentrations and intake rates span approximately 17 and 15 orders of magnitude, respectively. Estimates of exposure potential using human concentrations and a unit emission rate span approximately 13 orders of magnitude, and intake fractions span 7 orders of magnitude. The actual chemical emission rate contributes the greatest variance (uncertainty) in exposure estimates. The human biotransformation half-life is the second greatest source of uncertainty in estimated concentrations. In general, biotransformation and biodegradation half-lives are greater sources of uncertainty in modeled exposure and exposure potential than chemical partition coefficients. Mechanistic exposure modeling is suitable for screening and prioritizing large numbers of chemicals. By including uncertainty analysis and uncertainty in chemical information in the exposure estimates, these methods can help identify and address the important sources of uncertainty in human exposure and risk assessment in a systematic manner.

  11. Aircrew radiation exposure assessment for Yugoslav airlines

    Energy Technology Data Exchange (ETDEWEB)

    Antic, Dragoljub [Vinca Inst. of Nuclear Sciences, Belgrade (Yugoslavia); Petrovic, Zika [Yugoslav Airlines, JAT, Bulevar umetnosti 16, 11001 Belgrade (Yugoslavia)

    1997-12-31

    The presented study shows that the crews of the intercontinental flights can receive significant annual effective doses (1.5-2.0 mSv). The exposure of the crews is comparable with natural radiation level on the ground level (it can be up to 5 times higher for some air crew members in the intercontinental flights), but smaller than maximum permissible dose for general population. The annual exposures of the passengers are generally smaller than the exposures of tile air crews. because the passengers have a limited number of flights per year compared with the members of the air-crews. (author).

  12. Assessing radiation impact at a protected coastal sand dune site: an intercomparison of models for estimating the radiological exposure of non-human biota

    International Nuclear Information System (INIS)

    Wood, Michael D.; Beresford, Nicholas A.; Barnett, Catherine L.; Copplestone, David; Leah, Richard T.

    2009-01-01

    This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R and D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured 90 Sr, 99 Tc, 137 Cs, 238 Pu, 239+240 Pu and 241 Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented.

  13. Comparative Assessment of Particulate Air Pollution Exposure from Municipal Solid Waste Incinerator Emissions

    Science.gov (United States)

    Ashworth, Danielle C.; Fuller, Gary W.; Toledano, Mireille B.; Font, Anna; Elliott, Paul; Hansell, Anna L.; de Hoogh, Kees

    2013-01-01

    Background. Research to date on health effects associated with incineration has found limited evidence of health risks, but many previous studies have been constrained by poor exposure assessment. This paper provides a comparative assessment of atmospheric dispersion modelling and distance from source (a commonly used proxy for exposure) as exposure assessment methods for pollutants released from incinerators. Methods. Distance from source and the atmospheric dispersion model ADMS-Urban were used to characterise ambient exposures to particulates from two municipal solid waste incinerators (MSWIs) in the UK. Additionally an exploration of the sensitivity of the dispersion model simulations to input parameters was performed. Results. The model output indicated extremely low ground level concentrations of PM10, with maximum concentrations of incinerator characteristics, magnitude of emissions, and surrounding meteorological and topographical conditions are considered. Reducing exposure misclassification is particularly important in environmental epidemiology to aid detection of low-level risks. PMID:23935644

  14. Systematic evaluation of observational methods assessing biomechanical exposures at work

    DEFF Research Database (Denmark)

    Takala, Esa-Pekka; Irmeli, Pehkonen; Forsman, Mikael

    2009-01-01

    by sorting the methods according to the several items evaluated.   Numerous methods have been developed to assess physical workload (biomechanical exposures) in order to identify hazards leading to musculoskeletal disorders, to monitor the effects of ergonomic changes, and for research. No indvidual method...... between observers Potential users NIOSH Lifting Eq. NA X - O, R Arbouw M - - O ACGIH Lifting TLV M - - O MAC - - M O, W(?) ManTRA - - - O, R(?),W(?) NZ Code for MH - - - O, W(?) Washington state ergonomic rule M X M O, W(?) BackEST ML - M R   Correspondence with valid reference: HM = High to moderate, L......), and Washington state model. MAC (UK), ManTRA (Australia), and New Zealand code are widely used for the assessment of risks in MMH but we did not found formal studies on validity of these methods. The inter-observer repeatability of MAC and the Washington state model has been found to be moderate. Back...

  15. Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace

    OpenAIRE

    Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon

    2015-01-01

    This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable ma...

  16. Development of a new fuzzy exposure model

    International Nuclear Information System (INIS)

    Vasconcelos, Wagner Eustaquio de; Lira, Carlos Alberto Brayner de Oliveira; Texeira, Marcello Goulart

    2007-01-01

    The main topic of this study is the development of an exposure fuzzy model to evaluate the exposure of inhabitants in an area containing uranium, which present a high natural background. In this work, a fuzzy model was created, based on some of the following main factors: activity concentration of uranium, physiological factors and characteristic customs of the exposed individuals. An inference block was created to evaluate some factors of radiation exposure. For this, AHP-fuzzy technique (Analytic Hierarchic Process) was used and its application was demonstrated for a subjected population to the radiation of the natural uranium. The Mandami type fuzzy model was also created from the opinion of specialists. The Monte Carlo method was used to generate a statistics of input data and the daily average exposure served as comparison parameter between the three techniques. The output fuzzy sets were expressed in form of linguistic variables, such as high, medium and low. In the qualitative analysis, the obtained results were satisfactory when translating the opinion of the specialists. In the quantitative analysis, the obtained values are part of the same fuzzy set as the values found in literature. The global results suggest that this type of fuzzy model is highly promising for analysis of exposure to ionizing radiation. (author)

  17. Development of a new fuzzy exposure model

    Energy Technology Data Exchange (ETDEWEB)

    Vasconcelos, Wagner Eustaquio de; Lira, Carlos Alberto Brayner de Oliveira [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil). Dept. de Energia Nuclear. Grupo de Engenharia de Reatores], E-mail: wagner@ufpe.br, E-mail: cabol@ufpe.br; Texeira, Marcello Goulart [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil). Terrestrial Modelling Group], E-mail: marcellogt@ime.eb.br

    2007-07-01

    The main topic of this study is the development of an exposure fuzzy model to evaluate the exposure of inhabitants in an area containing uranium, which present a high natural background. In this work, a fuzzy model was created, based on some of the following main factors: activity concentration of uranium, physiological factors and characteristic customs of the exposed individuals. An inference block was created to evaluate some factors of radiation exposure. For this, AHP-fuzzy technique (Analytic Hierarchic Process) was used and its application was demonstrated for a subjected population to the radiation of the natural uranium. The Mandami type fuzzy model was also created from the opinion of specialists. The Monte Carlo method was used to generate a statistics of input data and the daily average exposure served as comparison parameter between the three techniques. The output fuzzy sets were expressed in form of linguistic variables, such as high, medium and low. In the qualitative analysis, the obtained results were satisfactory when translating the opinion of the specialists. In the quantitative analysis, the obtained values are part of the same fuzzy set as the values found in literature. The global results suggest that this type of fuzzy model is highly promising for analysis of exposure to ionizing radiation. (author)

  18. Integration of Probabilistic Exposure Assessment and Probabilistic Hazard Characterization

    NARCIS (Netherlands)

    Voet, van der H.; Slob, W.

    2007-01-01

    A method is proposed for integrated probabilistic risk assessment where exposure assessment and hazard characterization are both included in a probabilistic way. The aim is to specify the probability that a random individual from a defined (sub)population will have an exposure high enough to cause a

  19. DREAM: a method for semi-quantitative dermal exposure assessment

    NARCIS (Netherlands)

    Wendel de Joode, B. van; Brouwer, D.H.; Kromhout, H.; Hemmen, J.J. van

    2003-01-01

    This paper describes a new method (DREAM) for structured, semi-quantitative dermal exposure assessment for chemical or biological agents that can be used in occupational hygiene or epidemiology. It is anticipated that DREAM could serve as an initial assessment of dermal exposure, amongst others,

  20. Progress in human exposure assessment for biocidal products

    NARCIS (Netherlands)

    Hemmen, J.J. van

    2004-01-01

    An important shortcoming in our present knowledge required for risk assessment of biocidal products is the assessment of human exposure. This knowledge gap has been filled in a preliminary fashion with the TNsG on human exposure to biocidal products (available from the ECB website). Explicit User

  1. Human exposure assessment: Approaches for chemicals (REACH) and biocides (BPD)

    NARCIS (Netherlands)

    Hemmen, J.J. van; Gerritsen-Ebben, R.

    2008-01-01

    The approaches that are indicated in the various guidance documents for the assessment of human exposure for chemicals and biocides are summarised. This reflects the TNsG (Technical notes for Guidance) version 2: human exposure assessment for biocidal products (1) under the BPD (Biocidal Products

  2. Sex Differences in Adolescent Depression: Stress Exposure and Reactivity Models

    Science.gov (United States)

    Hankin, Benjamin L.; Mermelstein, Robin; Roesch, Linda

    2007-01-01

    Stress exposure and reactivity models were examined as explanations for why girls exhibit greater levels of depressive symptoms than boys. In a multiwave, longitudinal design, adolescents' depressive symptoms, alcohol usage, and occurrence of stressors were assessed at baseline, 6, and 12 months later (N=538; 54.5% female; ages 13-18, average…

  3. Population models for time-varying pesticide exposure

    NARCIS (Netherlands)

    Jager T; Jong FMW de; Traas TP; LER; SEC

    2007-01-01

    A model has recently been developed at RIVM to predict the effects of variable exposure to pesticides of plant and animal populations in surface water. Before a pesticide is placed on the market, the environmental risk of the substance has to be assessed. This risk is estimated by comparing

  4. Parameterization models for pesticide exposure via crop consumption.

    Science.gov (United States)

    Fantke, Peter; Wieland, Peter; Juraske, Ronnie; Shaddick, Gavin; Itoiz, Eva Sevigné; Friedrich, Rainer; Jolliet, Olivier

    2012-12-04

    An approach for estimating human exposure to pesticides via consumption of six important food crops is presented that can be used to extend multimedia models applied in health risk and life cycle impact assessment. We first assessed the variation of model output (pesticide residues per kg applied) as a function of model input variables (substance, crop, and environmental properties) including their possible correlations using matrix algebra. We identified five key parameters responsible for between 80% and 93% of the variation in pesticide residues, namely time between substance application and crop harvest, degradation half-lives in crops and on crop surfaces, overall residence times in soil, and substance molecular weight. Partition coefficients also play an important role for fruit trees and tomato (Kow), potato (Koc), and lettuce (Kaw, Kow). Focusing on these parameters, we develop crop-specific models by parametrizing a complex fate and exposure assessment framework. The parametric models thereby reflect the framework's physical and chemical mechanisms and predict pesticide residues in harvest using linear combinations of crop, crop surface, and soil compartments. Parametric model results correspond well with results from the complex framework for 1540 substance-crop combinations with total deviations between a factor 4 (potato) and a factor 66 (lettuce). Predicted residues also correspond well with experimental data previously used to evaluate the complex framework. Pesticide mass in harvest can finally be combined with reduction factors accounting for food processing to estimate human exposure from crop consumption. All parametric models can be easily implemented into existing assessment frameworks.

  5. Assessing Climate Change Impacts on Wildfire Exposure in Mediterranean Areas.

    Science.gov (United States)

    Lozano, Olga M; Salis, Michele; Ager, Alan A; Arca, Bachisio; Alcasena, Fermin J; Monteiro, Antonio T; Finney, Mark A; Del Giudice, Liliana; Scoccimarro, Enrico; Spano, Donatella

    2017-10-01

    We used simulation modeling to assess potential climate change impacts on wildfire exposure in Italy and Corsica (France). Weather data were obtained from a regional climate model for the period 1981-2070 using the IPCC A1B emissions scenario. Wildfire simulations were performed with the minimum travel time fire spread algorithm using predicted fuel moisture, wind speed, and wind direction to simulate expected changes in weather for three climatic periods (1981-2010, 2011-2040, and 2041-2070). Overall, the wildfire simulations showed very slight changes in flame length, while other outputs such as burn probability and fire size increased significantly in the second future period (2041-2070), especially in the southern portion of the study area. The projected changes fuel moisture could result in a lengthening of the fire season for the entire study area. This work represents the first application in Europe of a methodology based on high resolution (250 m) landscape wildfire modeling to assess potential impacts of climate changes on wildfire exposure at a national scale. The findings can provide information and support in wildfire management planning and fire risk mitigation activities. © 2016 Society for Risk Analysis.

  6. Human exposure assessment to environmental chemicals using biomonitoring.

    Science.gov (United States)

    Calafat, Antonia M; Ye, Xiaoyun; Silva, Manori J; Kuklenyik, Zsuzsanna; Needham, Larry L

    2006-02-01

    In modern societies, humans may be exposed to a wide spectrum of environmental chemicals. Although the health significance of this exposure for many chemicals is unknown, studies to investigate the prevalence of exposure are warranted because of the chemicals' potential harmful health effects, as often indicated in animal studies. Three tools have been used to assess exposure: exposure history/questionnaire information, environmental monitoring, and biomonitoring (i.e. measuring concentrations of the chemicals, their metabolites, or their adducts in human specimens). We present an overview on the use of biomonitoring in exposure assessment using phthalates, bisphenol A and other environmental phenols, and perfluorinated chemicals as examples. We discuss some factors relevant for interpreting and understanding biomonitoring data, including selection of both biomarkers of exposure and human matrices, and toxicokinetic information. The use of biomonitoring in human risk assessment is not discussed.

  7. A probabilistic assessment of health risks associated with short-term exposure to tropospheric ozone

    Energy Technology Data Exchange (ETDEWEB)

    Whitfield, R.G; Biller, W.F.; Jusko, M.J.; Keisler, J.M.

    1996-06-01

    The work described in this report is part of a larger risk assessment sponsored by the U.S. Environmental Protection Agency. Earlier efforts developed exposure-response relationships for acute health effects among populations engaged in heavy exertion. Those efforts also developed a probabilistic national ambient air quality standards exposure model and a general methodology for integrating probabilistic exposure-response relation- ships and exposure estimates to calculate overall risk results. Recently published data make it possible to model additional health endpoints (for exposure at moderate exertion), including hospital admissions. New air quality and exposure estimates for alternative national ambient air quality standards for ozone are combined with exposure-response models to produce the risk results for hospital admissions and acute health effects. Sample results explain the methodology and introduce risk output formats.

  8. Assessment of exposure-response functions for rocket-emission toxicants

    National Research Council Canada - National Science Library

    Subcommittee on Rocket-Emission Toxicants, National Research Council

    ... aborted launch that results in a rocket being destroyed near the ground. Assessment of Exposure-Response Functions for Rocket-Emmission Toxicants evaluates the model and the data used for three rocket emission toxicants...

  9. Ab initio chemical safety assessment: A workflow based on exposure considerations and non-animal methods

    OpenAIRE

    Berggren, Elisabet; White, Andrew; Ouedraogo, Gladys; Paini, Alicia; Richarz, Andrea-Nicole; Bois, Frederic Y.; Exner, Thomas; Leite, Sofia; Grunsven, Leo A. van; Worth, Andrew; Mahony, Catherine

    2017-01-01

    Highlights • A workflow for an exposure driven chemical safety assessment to avoid animal testing. • Hypothesis based on existing data, in silico modelling and biokinetic considerations. • A tool to inform targeted and toxicologically relevant in vitro testing.

  10. Retrospective benzene and total hydrocarbon exposure assessment for a petroleum marketing and distribution worker epidemiology study.

    Science.gov (United States)

    Armstrong, T W; Pearlman, E D; Schnatter, A R; Bowes, S M; Murray, N; Nicolich, M J

    1996-04-01

    A quantitative exposure-estimating algorithm for benzene and total hydrocarbons was developed for a case control study of petroleum marketing and distribution workers. The algorithm used a multiplicative model to adjust recently measured quantitative exposure data to past scenarios for which representative exposure measurement data did not exist. This was accomplished through the development of exposure modifiers to account for differences in the workplace, the materials handled, the environmental conditions, and the tasks performed. Values for exposure modifiers were obtained empirically and through physical/chemical relationships. Dates for changes that altered exposure potential were obtained from archive records, retired employee interviews, and from current operations personnel. Exposure modifiers were used multiplicatively, adjusting available measured data to represent the relevant exposure scenario and time period. Changes in exposure modifiers translated to step changes in exposure estimates. Though limited by availability of data, a validation exercise suggested that the algorithm provided accurate exposure estimates for benzene (compared with measured data in industrial hygiene survey reports); the estimates generally differed by an average of less than 20% from the measured values. This approach is proposed to quantify exposures retrospectively where there are sufficient data to develop reliable current era estimates and where a historical accounting of key exposure modifiers can be developed, but where there are insufficient historic exposure measurements to directly assess historic exposures.

  11. Assessment of annual exposure for grout operations

    International Nuclear Information System (INIS)

    Potter, R.E.

    1994-01-01

    An analysis is presented of the direct radiation exposures and dose rates to personnel from assumed quantities of radioactive grout, and Double Shell Tank (DST) waste feed. This analysis was based on filling four disposal vaults per year. Whole body doses were analyzed for occupational workers assigned to the Grout Treatment Facility (GTF). The study makes assumptions that must be met by the facility. Otherwise, the GTF will meet all DOE and WHC direct radiation exposure criteria. This analysis will be published in the Grout Final Safety Analysis Report (FSAR)

  12. Ecological and human exposure assessment to PBDEs in Adige River.

    Science.gov (United States)

    Giulivo, Monica; Suciu, Nicoleta Alina; Eljarrat, Ethel; Gatti, Marina; Capri, Ettore; Barcelo, Damia

    2018-07-01

    The interest for environmental issues and the concern resulting from the potential exposure to contaminants were the starting point to develop methodologies in order to evaluate the consequences that those might have over both the environment and human health. Considering the feature of POPs, including PBDEs, such as bioaccumulation, biomagnification, long-range transport and adverse effects even long time after exposure, risk assessment of POPs requires specific approaches and tools. In this particular context, the MERLIN-Expo tool was used to assess the aquatic environmental exposure of Adige River to PBDEs and the accumulation of PBDEs in humans through the consumption of possible contaminated local aquatic food. The aquatic food web models provided as output of the deterministic simulation the time trend of concentrations for twenty years of BDE-47 and total PBDEs, expressed using the physico-chemical properties of BDE-47, in aquatic organisms of the food web of Adige River. For BDE-47, the highest accumulated concentrations were detected for two benthic species: Thymallus thymallus and Squalius cephalus whereas the lowest concentrations were obtained for the pelagic specie Salmo trutta marmoratus. The trend obtained for the total PBDEs, calculated using the physico-chemical properties of BDE-47, follows the one of BDE-47. For human exposure, different BDE-47 and total PBDEs concentration trends between children, adolescent, adults and elderly were observed, probably correlated with the human intake of fish products in the daily diet and the ability to metabolize these contaminants. In detail, for the adolescents, adults and elderly a continuous accumulation of the target contaminants during the simulation's years was observed, whereas for children a plateau at the end of the simulation period was perceived. Copyright © 2018 Elsevier Inc. All rights reserved.

  13. An approach for assessing human exposures to chemical mixtures in the environment

    International Nuclear Information System (INIS)

    Rice, Glenn; MacDonell, Margaret; Hertzberg, Richard C.; Teuschler, Linda; Picel, Kurt; Butler, Jim; Chang, Young-Soo; Hartmann, Heidi

    2008-01-01

    Humans are exposed daily to multiple chemicals, including incidental exposures to complex chemical mixtures released into the environment and to combinations of chemicals that already co-exist in the environment because of previous releases from various sources. Exposures to chemical mixtures can occur through multiple pathways and across multiple routes. In this paper, we propose an iterative approach for assessing exposures to environmental chemical mixtures; it is similar to single-chemical approaches. Our approach encompasses two elements of the Risk Assessment Paradigm: Problem Formulation and Exposure Assessment. Multiple phases of the assessment occur in each element of the paradigm. During Problem Formulation, analysts identify and characterize the source(s) of the chemical mixture, ensure that dose-response and exposure assessment measures are concordant, and develop a preliminary evaluation of the mixture's fate. During Exposure Assessment, analysts evaluate the fate of the chemicals comprising the mixture using appropriate models and measurement data, characterize the exposure scenario, and estimate human exposure to the mixture. We also describe the utility of grouping the chemicals to be analyzed based on both physical-chemical properties and an understanding of environmental fate. In the article, we also highlight the need for understanding of changes in the mixture composition in the environment due to differential transport, differential degradation, and differential partitioning to other media. The section describes the application of the method to various chemical mixtures, highlighting issues associated with assessing exposures to chemical mixtures in the environment

  14. Assessing radiological impacts (exposures and doses) associated with the mining and milling of radioactive ores

    International Nuclear Information System (INIS)

    Williams, G.A.

    1990-01-01

    The basic units and concepts applicable to radiological assessment are presented. Data relevant to the assessment of radiological exposures from the mining and milling phases of uranium and thorium ores are discussed. As a guide to the assessment of environmental exposures to members of the public, concepts such as the critical group are defined. Environmental transport and exposure pathways are presented in general terms, together with a discussion of the use of mathematical models. The dose assessment procedures defined in the 1987 Code of Practice are described. 13 refs., 2 tabs., 1 fig

  15. Probabilistic quantitative microbial risk assessment model of norovirus from wastewater irrigated vegetables in Ghana using genome copies and fecal indicator ratio conversion for estimating exposure dose.

    Science.gov (United States)

    Owusu-Ansah, Emmanuel de-Graft Johnson; Sampson, Angelina; Amponsah, Samuel K; Abaidoo, Robert C; Dalsgaard, Anders; Hald, Tine

    2017-12-01

    The need to replace the commonly applied fecal indicator conversions ratio (an assumption of 1:10 -5 virus to fecal indicator organism) in Quantitative Microbial Risk Assessment (QMRA) with models based on quantitative data on the virus of interest has gained prominence due to the different physical and environmental factors that might influence the reliability of using indicator organisms in microbial risk assessment. The challenges facing analytical studies on virus enumeration (genome copies or particles) have contributed to the already existing lack of data in QMRA modelling. This study attempts to fit a QMRA model to genome copies of norovirus data. The model estimates the risk of norovirus infection from the intake of vegetables irrigated with wastewater from different sources. The results were compared to the results of a corresponding model using the fecal indicator conversion ratio to estimate the norovirus count. In all scenarios of using different water sources, the application of the fecal indicator conversion ratio underestimated the norovirus disease burden, measured by the Disability Adjusted Life Years (DALYs), when compared to results using the genome copies norovirus data. In some cases the difference was >2 orders of magnitude. All scenarios using genome copies met the 10 -4 DALY per person per year for consumption of vegetables irrigated with wastewater, although these results are considered to be highly conservative risk estimates. The fecal indicator conversion ratio model of stream-water and drain-water sources of wastewater achieved the 10 -6 DALY per person per year threshold, which tends to indicate an underestimation of health risk when compared to using genome copies for estimating the dose. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. [The methods of assessment of health risk from exposure to radon and radon daughters].

    Science.gov (United States)

    Demin, V F; Zhukovskiy, M V; Kiselev, S M

    2014-01-01

    The critical analysis of existing models of the relationship dose-effect (RDE) for radon exposure on human health has been performed. Conclusion about the necessity and possibility of improving these models has been made. A new improved version ofthe RDE has been developed. A technique for assessing the human health risk of exposure to radon, including the method for estimating of exposure doses of radon, an improved model of RDE, proper methodology risk assessment has been described. Methodology is proposed for the use in the territory of Russia.

  17. Exposure Data for Travel Risk Assessment

    DEFF Research Database (Denmark)

    Jørgensen, N O; Koornstra, Matthijs; Broughton, Jeremy

    1999-01-01

    This report illustrates why risk and exposure data are critical for policymaking at local, national and EU levels.Conclusions are drawn about the evaluation and use of risk information for different modes and estimates are presented for the fatality risk of various travel modes in the EU....

  18. Exposure assessment of process-related contaminants in food by biomarker monitoring.

    Science.gov (United States)

    Rietjens, Ivonne M C M; Dussort, P; Günther, Helmut; Hanlon, Paul; Honda, Hiroshi; Mally, Angela; O'Hagan, Sue; Scholz, Gabriele; Seidel, Albrecht; Swenberg, James; Teeguarden, Justin; Eisenbrand, Gerhard

    2018-01-01

    Exposure assessment is a fundamental part of the risk assessment paradigm, but can often present a number of challenges and uncertainties. This is especially the case for process contaminants formed during the processing, e.g. heating of food, since they are in part highly reactive and/or volatile, thus making exposure assessment by analysing contents in food unreliable. New approaches are therefore required to accurately assess consumer exposure and thus better inform the risk assessment. Such novel approaches may include the use of biomarkers, physiologically based kinetic (PBK) modelling-facilitated reverse dosimetry, and/or duplicate diet studies. This review focuses on the state of the art with respect to the use of biomarkers of exposure for the process contaminants acrylamide, 3-MCPD esters, glycidyl esters, furan and acrolein. From the overview presented, it becomes clear that the field of assessing human exposure to process-related contaminants in food by biomarker monitoring is promising and strongly developing. The current state of the art as well as the existing data gaps and challenges for the future were defined. They include (1) using PBK modelling and duplicate diet studies to establish, preferably in humans, correlations between external exposure and biomarkers; (2) elucidation of the possible endogenous formation of the process-related contaminants and the resulting biomarker levels; (3) the influence of inter-individual variations and how to include that in the biomarker-based exposure predictions; (4) the correction for confounding factors; (5) the value of the different biomarkers in relation to exposure scenario's and risk assessment, and (6) the possibilities of novel methodologies. In spite of these challenges it can be concluded that biomarker-based exposure assessment provides a unique opportunity to more accurately assess consumer exposure to process-related contaminants in food and thus to better inform risk assessment.

  19. Assessing radiation impact at a protected coastal sand dune site: an intercomparison of models for estimating the radiological exposure of non-human biota

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Michael D., E-mail: mwood@liv.ac.u [Institute for Sustainable Water Integrated Management and Ecosystem Research (SWIMMER), Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom); School of Biological Sciences, Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom); Beresford, Nicholas A.; Barnett, Catherine L. [Centre for Ecology and Hydrology, Lancaster Environment Centre, Library Avenue, Bailrigg, Lancaster, Lancashire LA1 4AP (United Kingdom); Copplestone, David [Environment Agency, PO Box 12, Richard Fairclough House, Knutsford Road, Latchford, Warrington, Cheshire WA4 1HG (United Kingdom); Leah, Richard T. [Institute for Sustainable Water Integrated Management and Ecosystem Research (SWIMMER), Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom); School of Biological Sciences, Nicholson Building, University of Liverpool, Liverpool, Merseyside L69 3GP (United Kingdom)

    2009-12-15

    This paper presents the application of three publicly available biota dose assessment models (the ERICA Tool, R and D128/SP1a and RESRAD-BIOTA) to an assessment of the Drigg coastal sand dunes. Using measured {sup 90}Sr, {sup 99}Tc, {sup 137}Cs, {sup 238}Pu, {sup 239+240}Pu and {sup 241}Am activity concentrations in sand dune soil, activity concentration and dose rate predictions are made for a range of organisms including amphibians, birds, invertebrates, mammals, reptiles, plants and fungi. Predicted biota activity concentrations are compared to measured data where available. The main source of variability in the model predictions is the transfer parameters used and it is concluded that developing the available transfer databases should be a focus of future research effort. The value of taking an informed user approach to investigate the way in which models may be expected to be applied in practice is highlighted and a strategy for the future development of intercomparison exercises is presented.

  20. Assessment of Po-210 exposure for the Italian population

    International Nuclear Information System (INIS)

    Clemente, G.F.; Renzetti, A.; Santori, G.; Breuer, F.

    1980-01-01

    Most of the natural internal dose of the general population due to alpha particles is associated with 210 Po exposure. The experimental data obtained to evaluate the levels of 210 Po exposure to members of the general Italian population and to some critical population groups exposed to high radon and daughter air concentration are summarized. The 210 Po content was measured in the following: a) daily diets; b) urinary excretions from members of the general population, both non-smokers and smokers; c) urinary excretions from workers in radioactive spas and non-uranium mines; d) teeth and bone samples from the general population. In most samples the content of 210 Pb, was also measured to assess the behaviour of 210 Po in man. A mathematical model fitting the experimental data was developed to describe the metabolism of systemic 210 Po. Four different levels of 210 Po exposure were detected according to the internal burden measured in the considered subjects. The corresponding dose rate to cortical and trabecular bone and soft tissue was evaluated. The values of the mean dose to the skeleton (cortical bone) were found to range from about 70 μGy/year for non-smokers of the general population to about 2 mGy/year for individuals working inside radioactive spas. (H.K.)

  1. Addressing bystander exposure to agricultural pesticides in life cycle impact assessment

    DEFF Research Database (Denmark)

    Ryberg, Morten Walbech; Rosenbaum, Ralph K.; Mosqueron, Luc

    2018-01-01

    Residents living near agricultural fields may be exposed to pesticides drifting from the fields after application to different field crops. To address this currently missing exposure pathway in life cycle assessment (LCA), we developed a modeling framework for quantifying exposure of bystanders...... magnitude of individual bystanders can be substantially larger than the exposure of populations not living in the proximity to agricultural fields. Our framework for assessing bystander exposure to pesticide applications closes a relevant gap in the exposure assessment included in LCA for agricultural...... to pesticide spray drift from agricultural fields. Our framework consists of three parts addressing: (1) loss of pesticides from an agricultural field via spray drift; (2) environmental fate of pesticide in air outside of the treated field; and (3) exposure of bystanders to pesticides via inhalation...

  2. Modeling population exposures to silver nanoparticles present in consumer products

    Science.gov (United States)

    Royce, Steven G.; Mukherjee, Dwaipayan; Cai, Ting; Xu, Shu S.; Alexander, Jocelyn A.; Mi, Zhongyuan; Calderon, Leonardo; Mainelis, Gediminas; Lee, KiBum; Lioy, Paul J.; Tetley, Teresa D.; Chung, Kian Fan; Zhang, Junfeng; Georgopoulos, Panos G.

    2014-11-01

    Exposures of the general population to manufactured nanoparticles (MNPs) are expected to keep rising due to increasing use of MNPs in common consumer products (PEN 2014). The present study focuses on characterizing ambient and indoor population exposures to silver MNPs (nAg). For situations where detailed, case-specific exposure-related data are not available, as in the present study, a novel tiered modeling system, Prioritization/Ranking of Toxic Exposures with GIS (geographic information system) Extension (PRoTEGE), has been developed: it employs a product life cycle analysis (LCA) approach coupled with basic human life stage analysis (LSA) to characterize potential exposures to chemicals of current and emerging concern. The PRoTEGE system has been implemented for ambient and indoor environments, utilizing available MNP production, usage, and properties databases, along with laboratory measurements of potential personal exposures from consumer spray products containing nAg. Modeling of environmental and microenvironmental levels of MNPs employs probabilistic material flow analysis combined with product LCA to account for releases during manufacturing, transport, usage, disposal, etc. Human exposure and dose characterization further employ screening microenvironmental modeling and intake fraction methods combined with LSA for potentially exposed populations, to assess differences associated with gender, age, and demographics. Population distributions of intakes, estimated using the PRoTEGE framework, are consistent with published individual-based intake estimates, demonstrating that PRoTEGE is capable of capturing realistic exposure scenarios for the US population. Distributions of intakes are also used to calculate biologically relevant population distributions of uptakes and target tissue doses through human airway dosimetry modeling that takes into account product MNP size distributions and age-relevant physiological parameters.

  3. SHEDS-HT: an integrated probabilistic exposure model for prioritizing exposures to chemicals with near-field and dietary sources.

    Science.gov (United States)

    Isaacs, Kristin K; Glen, W Graham; Egeghy, Peter; Goldsmith, Michael-Rock; Smith, Luther; Vallero, Daniel; Brooks, Raina; Grulke, Christopher M; Özkaynak, Halûk

    2014-11-04

    United States Environmental Protection Agency (USEPA) researchers are developing a strategy for high-throughput (HT) exposure-based prioritization of chemicals under the ExpoCast program. These novel modeling approaches for evaluating chemicals based on their potential for biologically relevant human exposures will inform toxicity testing and prioritization for chemical risk assessment. Based on probabilistic methods and algorithms developed for The Stochastic Human Exposure and Dose Simulation Model for Multimedia, Multipathway Chemicals (SHEDS-MM), a new mechanistic modeling approach has been developed to accommodate high-throughput (HT) assessment of exposure potential. In this SHEDS-HT model, the residential and dietary modules of SHEDS-MM have been operationally modified to reduce the user burden, input data demands, and run times of the higher-tier model, while maintaining critical features and inputs that influence exposure. The model has been implemented in R; the modeling framework links chemicals to consumer product categories or food groups (and thus exposure scenarios) to predict HT exposures and intake doses. Initially, SHEDS-HT has been applied to 2507 organic chemicals associated with consumer products and agricultural pesticides. These evaluations employ data from recent USEPA efforts to characterize usage (prevalence, frequency, and magnitude), chemical composition, and exposure scenarios for a wide range of consumer products. In modeling indirect exposures from near-field sources, SHEDS-HT employs a fugacity-based module to estimate concentrations in indoor environmental media. The concentration estimates, along with relevant exposure factors and human activity data, are then used by the model to rapidly generate probabilistic population distributions of near-field indirect exposures via dermal, nondietary ingestion, and inhalation pathways. Pathway-specific estimates of near-field direct exposures from consumer products are also modeled

  4. Assessing the risks from exposure to radon in dwellings

    International Nuclear Information System (INIS)

    Walsh, P.J.; Lowder, W.M.

    1983-07-01

    The factors used to assess the radiation dose and health risks from human exposure to radon in dwellings are critically reviewed in this summary. Sources of indoor radon and determinants of air concentrations and exposure levels are given as well as the uncertainties that exist in their formulation. Methods of assessing health effects from inhalation of radon and its progeny are discussed with emphasis on dosimetry of radon daughters and formulation of risk per dose values. Finally, methods of assessing risks for general population exposures to indoor radon concentrations are treated

  5. Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace

    Directory of Open Access Journals (Sweden)

    Hyeon-Yeong Kim

    2015-05-01

    Full Text Available This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m3, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10−4 (central tendency exposure and 0.56 × 10−4 (reasonable maximum exposure, which is below the acceptable risk value of 1.0 × 10−4. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.

  6. Exposure monitoring and risk assessment of biphenyl in the workplace.

    Science.gov (United States)

    Kim, Hyeon-Yeong; Shin, Sae-Mi; Ham, Miran; Lim, Cheol-Hong; Byeon, Sang-Hoon

    2015-05-13

    This study was performed to assess exposure to and the risk caused by biphenyl in the workplace. Biphenyl is widely used as a heat transfer medium and as an emulsifier and polish in industry. Vapor or high levels of dust inhalation and dermal exposure to biphenyl can cause eye inflammation, irritation of respiratory organs, and permanent lesions in the liver and nervous system. In this study, the workplace environment concentrations were assessed as central tendency exposure and reasonable maximum exposure and were shown to be 0.03 and 0.12 mg/m³, respectively. In addition, the carcinogenic risk of biphenyl as determined by risk assessment was 0.14 × 10⁻⁴ (central tendency exposure) and 0.56 × 10⁻⁴ (reasonable maximum exposure), which is below the acceptable risk value of 1.0 × 10⁻⁴. Furthermore, the central tendency exposure and reasonable maximum exposure hazard quotients were 0.01 and 0.06 for oral toxicity, 0.05 and 0.23 for inhalation toxicity, and 0.08 and 0.39 for reproduction toxicity, respectively, which are all lower than the acceptable hazard quotient of 1.0. Therefore, exposure to biphenyl was found to be safe in current workplace environments. Because occupational exposure limits are based on socioeconomic assessment, they are generally higher than true values seen in toxicity experiments. Based on the results of exposure monitoring of biphenyl, the current occupational exposure limits in Korea could be reviewed.

  7. Exposure assessment of JAVELIN missile combustion products

    Science.gov (United States)

    Lundy, Donald O.; Langford, Roland E.

    1994-02-01

    Characterization and analysis of combustion products resulting from firing the JAVELIN missile were performed. Of those combustion products analyzed, it was determined that airborne lead concentrations exceeded the OSHA PEL of 50 micrograms each time the missile was fired while in the enclosure. Since the OSHA PEL standard is based upon a continuous rather than a short-term exposures blood lead concentrations were sought to ascertain the relationship between a short duration airborne exposure and its physiological effect on the body. Blood lead levels were taken on 49 test subjects prior to various JAVELIN missile test firings. Of those 49, 21 were outfitted With personal sampling equipment to determine airborne concentrations at the Assistant Gunner and Gunner positions. Periodic blood sampling after a single exposure showed an average increase of 2.27 micrograms/dL for all test subjects. Recommendations were made to consider changes in the positioning of the enclosure inhabitants to minimize airborne lead concentrations, to limit the number of missiles fired (situation dependent), and replacement of the lead B-resorcyolate with a non-lead containing burn rate modifier for the launch motor.

  8. Modeling residential exposure to secondhand tobacco smoke

    Science.gov (United States)

    Klepeis, Neil E.; Nazaroff, William W.

    We apply a simulation model to explore the effect of a house's multicompartment character on a nonsmoker's inhalation exposure to secondhand tobacco smoke (SHS). The model tracks the minute-by-minute movement of people and pollutants among multiple zones of a residence and generates SHS pollutant profiles for each room in response to room-specific smoking patterns. In applying the model, we consider SHS emissions of airborne particles, nicotine, and carbon monoxide in two hypothetical houses, one with a typical four-room layout and one dominated by a single large space. We use scripted patterns of room-to-room occupant movement and a cohort of 5000 activity patterns sampled from a US nationwide survey. The results for scripted and cohort simulation trials indicate that the multicompartment nature of homes, manifested as inter-room differences in pollutant levels and the movement of people among zones, can cause substantial variation in nonsmoker SHS exposure.

  9. Harmonizing exposure metrics and methods for sustainability assessments of food contact materials

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Jolliet, Olivier; Niero, Monia

    2016-01-01

    ) and Cradle to Cradle to support packaging design. Each assessment has distinct context and goals, but can help manage exposure to toxic chemicals and other environmental impacts. Metrics a nd methods to quantify and characterize exposure to potentially toxic chemicals specifically in food packaging are......, however, notably lacking from such assessments. Furthermore, previous case studies demonstrated that sustainable packaging design focuses, such as decreasing greenhouse gas emissions or resource consumption, can increase exposure to toxic chemicals through packaging. Thereby, developing harmonized methods...... for quantifying exposure to chemicals in food packaging is critical to ensure ‘sustainable packages’ do not increase exposure to toxic chemicals. Therefore we developed modelling methods suitable for first-tier risk screening and environmental assessments. The modelling framework was based on the new product...

  10. Exposure Assessment Tools by Tiers and Types - Deterministic and Probabilistic Assessments

    Science.gov (United States)

    EPA ExpoBox is a toolbox for exposure assessors. Its purpose is to provide a compendium of exposure assessment and risk characterization tools that will present comprehensive step-by-step guidance and links to relevant exposure assessment data bases

  11. Wishful Thinking? Inside the Black Box of Exposure Assessment.

    Science.gov (United States)

    Money, Annemarie; Robinson, Christine; Agius, Raymond; de Vocht, Frank

    2016-05-01

    Decision-making processes used by experts when undertaking occupational exposure assessment are relatively unknown, but it is often assumed that there is a common underlying method that experts employ. However, differences in training and experience of assessors make it unlikely that one general method for expert assessment would exist. Therefore, there are concerns about formalizing, validating, and comparing expert estimates within and between studies that are difficult, if not impossible, to characterize. Heuristics on the other hand (the processes involved in decision making) have been extensively studied. Heuristics are deployed by everyone as short-cuts to make the often complex process of decision-making simpler, quicker, and less burdensome. Experts' assessments are often subject to various simplifying heuristics as a way to reach a decision in the absence of sufficient data. Therefore, investigating the underlying heuristics or decision-making processes involved may help to shed light on the 'black box' of exposure assessment. A mixed method study was conducted utilizing both a web-based exposure assessment exercise incorporating quantitative and semiqualitative elements of data collection, and qualitative semi-structured interviews with exposure assessors. Qualitative data were analyzed using thematic analysis. Twenty-five experts completed the web-based exposure assessment exercise and 8 of these 25 were randomly selected to participate in the follow-up interview. Familiar key themes relating to the exposure assessment exercise emerged; 'intensity'; 'probability'; 'agent'; 'process'; and 'duration' of exposure. However, an important aspect of the detailed follow-up interviews revealed a lack of structure and order with which participants described their decision making. Participants mostly described some form of an iterative process, heavily relying on the anchoring and adjustment heuristic, which differed between experts. In spite of having undertaken

  12. A flexible matrix-based human exposure assessment framework suitable for LCA and CAA

    DEFF Research Database (Denmark)

    Jolliet, Olivier; Ernstoff, Alexi; Huang, Lei

    2016-01-01

    are not applicable to all types of near-field chemical releases from consumer products, e.g. direct dermal application. A consistent near-and far-field framework is needed for life cycle assessment (LCA) and chemical alternative assessment (CAA) to inform mitigation of human exposure to harmful chemicals. To close......Humans can be exposed to chemicals via near-field exposure pathways (e.g. through consumer product use) and far-field exposure pathways (e.g. through environmental emissions along product life cycles). Pathways are often complex where chemicals can transfer directly from products to humans during...... use or exchange between near-and far-field compartments until sub -fractions reach humans via inhalation, ingestion or dermal uptake. Currently, however, multimedia exposure models mainly focus on far-field exposure pathways. Metrics and modeling approaches used in far-field, emission-based models...

  13. Lead concentrations and risk exposure assessment in surface soils ...

    African Journals Online (AJOL)

    Lead concentrations and risk exposure assessment in surface soils at residential lands previously used for auto-mechanic and auto-welding activities in Port Harcourt, Nigeria. ... Journal of Applied Sciences and Environmental Management.

  14. Aggregate exposure pathways in support of risk assessment

    Science.gov (United States)

    Over time, risk assessment has shifted from establishing relationships between exposure to a single chemical and a resulting adverse health outcome, to evaluating multiple chemicals and disease outcomes simultaneously. As a result, there is an increasing need to better understand...

  15. Existing Default Values and Recommendations for Exposure Assessment - A Nordic Exposure Group Project 2011

    DEFF Research Database (Denmark)

    Höglund, Lena; Räisänen, Jouni; Hämäläinen, Anne-Maija

    range of more or less well-documented values originating from many different sources. The purpose of this report is to give an overview and to evaluate exposure factors that are currently used by the authorities and industry in the exposure assessments for both adults (occupational and consumer exposure......) and children in relation to REACH. Another important purpose of the report is to contribute towards a further harmonisation of exposure factors by giving recommendations of most valid and representative defaults. These recommendations can be used besides REACH also in biocide's and plant protection product...

  16. Test measurements on a secco white-lead containing model samples to assess the effects of exposure to low-fluence UV laser radiation

    Science.gov (United States)

    Raimondi, Valentina; Andreotti, Alessia; Colombini, Maria Perla; Cucci, Costanza; Cuzman, Oana; Galeotti, Monica; Lognoli, David; Palombi, Lorenzo; Picollo, Marcello; Tiano, Piero

    2015-05-01

    Laser-induced fluorescence technique is widely used for diagnostic purposes in several applications and its use could be of advantage for non-invasive on-site characterisation of pigments or other compounds in wall paintings. However, it is well known that long-time exposure to UV and VIS radiation can cause damage to wall paintings. Several studies have investigated the effects of lighting, e.g., in museums: however, the effects of low-fluence laser radiation have not been studied much so far. This paper investigates the effects of UV laser radiation using fluences in the range of 0.1 mJ/cm2-1 mJ/cm2 on a set of a secco model samples prepared with lead white and different type of binders (animal glue and whole egg, whole egg, skimmed milk, egg-oil tempera). The samples were irradiated using a Nd:YAG laser (emission wavelength at 355 nm; pulse width: 5 ns) by applying laser fluences between 0.1 mJ/cm2 and 1 mJ/cm2 and a number of laser pulses between 1 and 500. The samples were characterised before and after laser irradiation by using several techniques (colorimetry, optical microscopy, fibre optical reflectance spectroscopy, FT-IR spectroscopy Attenuated Total Reflectance microscopy and gas chromatography/mass spectrometry), to detect variations in the morphological and physico-chemical properties. The results did not point out significant changes in the sample properties after irradiation in the proposed range of laser fluences.

  17. Assessment of soil lead exposure in children in Shenyang, China

    International Nuclear Information System (INIS)

    Ren, H.M.; Wang, J.D.; Zhang, X.L.

    2006-01-01

    Soil lead pollution is serious in Shenyang, China. The paper brings together the soil work, the bioaccessibility, and the blood lead data to assess the soil lead exposure in children in Shenyang, China. Approximately 15.25% of the samples were above China Environment Protection Agency guideline concentration for soil Pb to protect human from health risk (350 mg kg -1 ). Pb concentrations varied among use scenarios. The main lead contamination sources are industry emission and automobile exhaust. Bioaccessibility also varied among use scenarios. Children, who ingested soil from industrial area, public parks, kindergarten playground, and commercial area, are more susceptible to soil lead toxicity. The industrial area soil samples presented higher bioaccessibility compared to the other use scenario soil samples contaminated by automobile exhaust. The result also suggested a most significant linear relationship between the level of Pb contamination and the amount of Pb mobilized from soil into ingestion juice. Soil pH seemed to have insignificant influence on bioaccessibility in the present study. Bioaccessibility was mainly controlled by other factors that are not investigated in this study. A linear relationship between children blood lead and soil intestinal bioaccessibility was present in the study. Children who are 4-5 years old are more likely to demonstrate the significant relationship between soil lead bioaccessibility and blood lead as their behaviors place them at greatest risk of soil lead toxicity, and their blood lead levels are more likely to represent recent exposure. - Children were exposed to soil lead and the exposure was assessed by bioaccessibility using in vitro digestion model in a modified version

  18. Applicability of western chemical dietary exposure models to the Chinese population.

    Science.gov (United States)

    Zhao, Shizhen; Price, Oliver; Liu, Zhengtao; Jones, Kevin C; Sweetman, Andrew J

    2015-07-01

    A range of exposure models, which have been developed in Europe and North America, are playing an increasingly important role in priority setting and the risk assessment of chemicals. However, the applicability of these tools, which are based on Western dietary exposure pathways, to estimate chemical exposure to the Chinese population to support the development of a risk-based environment and exposure assessment, is unclear. Three frequently used modelling tools, EUSES, RAIDAR and ACC-HUMANsteady, have been evaluated in terms of human dietary exposure estimation by application to a range of chemicals with different physicochemical properties under both model default and Chinese dietary scenarios. Hence, the modelling approaches were assessed by considering dietary pattern differences only. The predicted dietary exposure pathways were compared under both scenarios using a range of hypothetical and current emerging contaminants. Although the differences across models are greater than those between dietary scenarios, model predictions indicated that dietary preference can have a significant impact on human exposure, with the relatively high consumption of vegetables and cereals resulting in higher exposure via plants-based foodstuffs under Chinese consumption patterns compared to Western diets. The selected models demonstrated a good ability to identify key dietary exposure pathways which can be used for screening purposes and an evaluative risk assessment. However, some model adaptations will be required to cover a number of important Chinese exposure pathways, such as freshwater farmed-fish, grains and pork. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Radiation in complex exposure situations. Assessing health risks at low levels from concomitant exposures to radiation and chemicals

    International Nuclear Information System (INIS)

    Hornhardt, S.; Jung, T.; Burkart, W.

    2000-01-01

    Health effects from exposures to ionizing radiation are in general the result of complex multi-step reaction chains involving changes and responses on the level of molecules, cells, tissues and organisms. In environmental low dose exposure situations ionizing radiation only contributes a small fraction to the life-long attack on DNA by other exogenous and endogenous genotoxins. Nevertheless, efforts to assess and quantify deleterious effects at low exposure levels are directed mainly towards radiation as a single isolated agent, and rarely towards the concomitant presence of other natural and anthropogenic toxicants. Only these combined exposures may lead to observable health risk effects. In addition they might differ from those expected from simple addition of the individual risks due to interaction. The existing data base on combined effects is rudimentary, mainly descriptive and rarely covers exposure ranges large enough to make direct inferences to present day low dose exposure situations. Therefore, any risk assessment will have to consider the question whether combined effects, i.e. interaction between two or more agents will influence the health outcome from specific exposure situations in such a way that predictions derived from simple standard exposure situations would have to be revised. In view of the multitude of possible interactions between the large number of potentially harmful agents in the human environment, descriptive approaches will have to be supplemented by the use of mechanistic models for critical health endpoints such as cancer. Agents will have to be grouped depending on their physical or chemical mode of action at the molecular and cellular level, to generalize and predict the outcome of combined exposures at low exposure levels and the possibility of interactions. (author)

  20. Test measurements on a secco white-lead containing model samples to assess the effects of exposure to low-fluence UV laser radiation

    Energy Technology Data Exchange (ETDEWEB)

    Raimondi, Valentina, E-mail: v.raimondi@ifac.cnr.it [‘Nello Carrara’ Applied Physics Institute - National Research Council of Italy (CNR-IFAC), Firenze (Italy); Andreotti, Alessia; Colombini, Maria Perla [Chemistry and Industrial Chemistry Department (DCCI) - University of Pisa, Pisa (Italy); Cucci, Costanza [‘Nello Carrara’ Applied Physics Institute - National Research Council of Italy (CNR-IFAC), Firenze (Italy); Cuzman, Oana [Institute for the Conservation and Promotion of Cultural Heritage - National Research Council (CNR-ICVBC), Firenze (Italy); Galeotti, Monica [Opificio delle Pietre Dure (OPD), Firenze (Italy); Lognoli, David; Palombi, Lorenzo; Picollo, Marcello [‘Nello Carrara’ Applied Physics Institute - National Research Council of Italy (CNR-IFAC), Firenze (Italy); Tiano, Piero [Institute for the Conservation and Promotion of Cultural Heritage - National Research Council (CNR-ICVBC), Firenze (Italy)

    2015-05-15

    Highlights: • A set of a secco model samples was prepared using white lead and four different organic binders (animal glue and whole egg, whole egg, skimmed milk, egg-oil tempera). • The samples were irradiated with low-fluence UV laser pulses (0.1–1 mJ/cm{sup 2}). • The effects of laser irradiation were analysed by using different techniques. • The analysis did not point out changes due to low-fluence laser irradiation. • High fluence (88 mJ/cm{sup 2}) laser radiation instead yielded a chromatic change ascribed to the inorganic component. - Abstract: Laser-induced fluorescence technique is widely used for diagnostic purposes in several applications and its use could be of advantage for non-invasive on-site characterisation of pigments or other compounds in wall paintings. However, it is well known that long-time exposure to UV and VIS radiation can cause damage to wall paintings. Several studies have investigated the effects of lighting, e.g., in museums: however, the effects of low-fluence laser radiation have not been studied much so far. This paper investigates the effects of UV laser radiation using fluences in the range of 0.1 mJ/cm{sup 2}–1 mJ/cm{sup 2} on a set of a secco model samples prepared with lead white and different type of binders (animal glue and whole egg, whole egg, skimmed milk, egg-oil tempera). The samples were irradiated using a Nd:YAG laser (emission wavelength at 355 nm; pulse width: 5 ns) by applying laser fluences between 0.1 mJ/cm{sup 2} and 1 mJ/cm{sup 2} and a number of laser pulses between 1 and 500. The samples were characterised before and after laser irradiation by using several techniques (colorimetry, optical microscopy, fibre optical reflectance spectroscopy, FT-IR spectroscopy Attenuated Total Reflectance microscopy and gas chromatography/mass spectrometry), to detect variations in the morphological and physico-chemical properties. The results did not point out significant changes in the sample properties after

  1. Test measurements on a secco white-lead containing model samples to assess the effects of exposure to low-fluence UV laser radiation

    International Nuclear Information System (INIS)

    Raimondi, Valentina; Andreotti, Alessia; Colombini, Maria Perla; Cucci, Costanza; Cuzman, Oana; Galeotti, Monica; Lognoli, David; Palombi, Lorenzo; Picollo, Marcello; Tiano, Piero

    2015-01-01

    Highlights: • A set of a secco model samples was prepared using white lead and four different organic binders (animal glue and whole egg, whole egg, skimmed milk, egg-oil tempera). • The samples were irradiated with low-fluence UV laser pulses (0.1–1 mJ/cm 2 ). • The effects of laser irradiation were analysed by using different techniques. • The analysis did not point out changes due to low-fluence laser irradiation. • High fluence (88 mJ/cm 2 ) laser radiation instead yielded a chromatic change ascribed to the inorganic component. - Abstract: Laser-induced fluorescence technique is widely used for diagnostic purposes in several applications and its use could be of advantage for non-invasive on-site characterisation of pigments or other compounds in wall paintings. However, it is well known that long-time exposure to UV and VIS radiation can cause damage to wall paintings. Several studies have investigated the effects of lighting, e.g., in museums: however, the effects of low-fluence laser radiation have not been studied much so far. This paper investigates the effects of UV laser radiation using fluences in the range of 0.1 mJ/cm 2 –1 mJ/cm 2 on a set of a secco model samples prepared with lead white and different type of binders (animal glue and whole egg, whole egg, skimmed milk, egg-oil tempera). The samples were irradiated using a Nd:YAG laser (emission wavelength at 355 nm; pulse width: 5 ns) by applying laser fluences between 0.1 mJ/cm 2 and 1 mJ/cm 2 and a number of laser pulses between 1 and 500. The samples were characterised before and after laser irradiation by using several techniques (colorimetry, optical microscopy, fibre optical reflectance spectroscopy, FT-IR spectroscopy Attenuated Total Reflectance microscopy and gas chromatography/mass spectrometry), to detect variations in the morphological and physico-chemical properties. The results did not point out significant changes in the sample properties after irradiation in the proposed

  2. Quantifying human exposure to air pollution--moving from static monitoring to spatio-temporally resolved personal exposure assessment.

    Science.gov (United States)

    Steinle, Susanne; Reis, Stefan; Sabel, Clive Eric

    2013-01-15

    Quantifying human exposure to air pollutants is a challenging task. Ambient concentrations of air pollutants at potentially harmful levels are ubiquitous in urban areas and subject to high spatial and temporal variability. At the same time, every individual has unique activity-patterns. Exposure results from multifaceted relationships and interactions between environmental and human systems, adding complexity to the assessment process. Traditionally, approaches to quantify human exposure have relied on pollutant concentrations from fixed air quality network sites and static population distributions. New developments in sensor technology now enable us to monitor personal exposure to air pollutants directly while people are moving through their activity spaces and varying concentration fields. The literature review on which this paper is based on reflects recent developments in the assessment of human exposure to air pollution. This includes the discussion of methodologies and concepts, and the elaboration of approaches and study designs applied in the field. We identify shortcomings of current approaches and discuss future research needs. We close by proposing a novel conceptual model for the integrated assessment of human exposure to air pollutants taking into account latest technological capabilities and contextual information. Copyright © 2012 Elsevier B.V. All rights reserved.

  3. Assessment of occupational exposure to radiofrequency fields and radiation

    International Nuclear Information System (INIS)

    Cooper, T. G.; Allen, S. G.; Blackwell, R. P.; Litchfield, I.; Mann, S. M.; Pope, J. M.; Van Tongeren, M. J. A.

    2004-01-01

    The use of personal monitors for the assessment of exposure to radiofrequency fields and radiation in potential future epidemiological studies of occupationally exposed populations has been investigated. Data loggers have been developed for use with a commercially available personal monitor and these allowed personal exposure records consisting of time-tagged measurements of electric and magnetic field strength to be accrued over extended periods of the working day. The instrumentation was worn by workers carrying out tasks representative of some of their typical daily activities at a variety of radio sites. The results indicated significant differences in the exposures of workers in various RF environments. A number of measures of exposure have been examined with a view to assessing possible exposure metrics for epidemiological studies. There was generally a good correlation between a given measure of electric field strength and the same measure of magnetic field strength. (authors)

  4. The global assessment of medical radiation exposures

    International Nuclear Information System (INIS)

    Shannoun, F.

    2010-01-01

    World Health Organization (WHO) is the United Nations specialized agency which acts as a coordinating authority on international public health. It was established in 1948. It has 147 Country Offices, 6 Regional Offices and 193 Member States Ministries of Health Its headquarters is in Geneva. The World Health Assembly (WHA) requested WHO to s tudy the optimum use of ionizing radiation in medicine and the risks to health of excessive or improper use . (WHA, 1971) International Basic Safety Standards BSS) The (BSS) mark the culmination of efforts towards global harmonization of radiation safety requirements. However, the involvement of the health sector in the BSS implementation is still weak and scant. There is a need to mobilize the health sector towards safer and effective use of radiation in medicine. Radiation in Health Care The use of radiation in health care is by far the largest contributor to the exposure of the general population from artificial sources. Annually worldwide there are 3,600 million X-ray exams (> 300 million in children), 37 million nuclear medicine procedures and 7.5 million radiation oncology treatments [UNSCEAR Report 2008]. WHO Global Initiative on Radiation Safety in Health Care Settings Was launched in December 2008 It involved the following:- There was involvement of international organizations and professionals bodies, national health and radiation protection authorities, etc. Its aim is to improve the protection of patients and health care workers through better implementation of the BSS. It complements the International Action Plan for Radiological Protection of Patients established by the IAEA 7 UNSCEAR's medical exposure survey Objectives of UNSCEAR's survey were to facilitate evaluation of: - Global estimates of frequency and levels of exposures, with break-downs by medical procedure, age, sex, health care level, and country; - Trends in practice (including those relatively fast-changing); with supporting contextual

  5. Exposure assessment of tetrafluoroethylene and ammonium perfluorooctanoate 1951-2002.

    Science.gov (United States)

    Sleeuwenhoek, Anne; Cherrie, John W

    2012-03-01

    To develop a method to reconstruct exposure to tetrafluoroethylene (TFE) and ammonium perfluorooctanoate (APFO) in plants producing polytetrafluoroethylene (PTFE) in the absence of suitable objective measurements. These data were used to inform an epidemiological study being carried out to investigate possible risks in workers employed in the manufacture of PTFE and to study trends in exposure over time. For each plant, detailed descriptions of all occupational titles, including tasks and changes over time, were obtained during semi-structured interviews with key plant personnel. A semi-quantitative assessment method was used to assess inhalation exposure to TFE and inhalation plus dermal exposure to APFO. Temporal trends in exposure to TFE and APFO were investigated. In each plant the highest exposures for both TFE and APFO occurred in the polymerisation area. Due to the introduction of control measures, increasing process automation and other improvements, exposures generally decreased over time. In the polymerisation area, the annual decline in exposure to TFE varied by plant from 3.8 to 5.7% and for APFO from 2.2 to 5.5%. A simple method for assessing exposure was developed which used detailed process information and job descriptions to estimate average annual TFE and APFO exposure on an arbitrary semi-quantitative scale. These semi-quantitative estimates are sufficient to identify relative differences in exposure for the epidemiological study and should good data become available, they could be used to provide quantitative estimates for all plants across the whole period of operation. This journal is © The Royal Society of Chemistry 2012

  6. Standardizing measurement, sampling and reporting for public exposure assessments

    Energy Technology Data Exchange (ETDEWEB)

    Rochedo, Elaine R.R. [Instituto de Radioprotecao e Dosimetria, Comissao Nacional de Energia Nuclear, Av. Salvador Allende s/No. CEP 22780-160 Rio de Janeiro, RJ (Brazil)], E-mail: elaine@ird.gov.br

    2008-11-15

    UNSCEAR assesses worldwide public exposure from natural and man-made sources of ionizing radiation based on information submitted to UNSCEAR by United Nations Member States and from peer reviewed scientific literature. These assessments are used as a basis for radiation protection programs of international and national regulatory and research organizations. Although UNSCEAR describes its assessment methodologies, the data are based on various monitoring approaches. In order to reduce uncertainties and improve confidence in public exposure assessments, it would be necessary to harmonize the methodologies used for sampling, measuring and reporting of environmental results.

  7. Assessment of multiple frequency ELF electric and magnetic field exposure

    International Nuclear Information System (INIS)

    Leitgeb, N

    2008-01-01

    Electromagnetic fields both in daily life and at workplaces exhibit increasingly complex frequency spectra. Present spectral assessment rules proved to be too conservative for health risk assessment. This is because they are based on the assumption that cells would react like linear systems in terms of responding to a sum of frequencies by a sum of independent responses to each individual frequency. Based on numerical investigations with the Hodgkin-Huxley and the Frankenhaeuser-Huxley nerve cell models, it could be shown that accounting for the nonlinear behaviour of cellular excitation processes avoids considerable overestimation of simultaneous exposures to multiple frequency ELF electric and magnetic fields. Besides this, it could be shown that the role of phase relationships is less important than that assumed so far. The present assessment rules lead to non-compliances of marketed electric appliances. For general application, a nonlinear biology-based assessment (NBBA) rule has been proposed, validated and proven advantageous compared with ICNIRP's rule. While staying conservative it avoids unnecessary overestimation and demonstrates compliance even in cases of suspected non-conformities. It is up to responsible bodies to decide upon the adoption of this proposal and the potential need for implementing additional or reducing the already incorporated safety factors

  8. Ecological models and pesticide risk assessment: current modeling practice.

    Science.gov (United States)

    Schmolke, Amelie; Thorbek, Pernille; Chapman, Peter; Grimm, Volker

    2010-04-01

    Ecological risk assessments of pesticides usually focus on risk at the level of individuals, and are carried out by comparing exposure and toxicological endpoints. However, in most cases the protection goal is populations rather than individuals. On the population level, effects of pesticides depend not only on exposure and toxicity, but also on factors such as life history characteristics, population structure, timing of application, presence of refuges in time and space, and landscape structure. Ecological models can integrate such factors and have the potential to become important tools for the prediction of population-level effects of exposure to pesticides, thus allowing extrapolations, for example, from laboratory to field. Indeed, a broad range of ecological models have been applied to chemical risk assessment in the scientific literature, but so far such models have only rarely been used to support regulatory risk assessments of pesticides. To better understand the reasons for this situation, the current modeling practice in this field was assessed in the present study. The scientific literature was searched for relevant models and assessed according to nine characteristics: model type, model complexity, toxicity measure, exposure pattern, other factors, taxonomic group, risk assessment endpoint, parameterization, and model evaluation. The present study found that, although most models were of a high scientific standard, many of them would need modification before they are suitable for regulatory risk assessments. The main shortcomings of currently available models in the context of regulatory pesticide risk assessments were identified. When ecological models are applied to regulatory risk assessments, we recommend reviewing these models according to the nine characteristics evaluated here. (c) 2010 SETAC.

  9. Quantitative assessment of exposure and risk for three carcinogenics in long-standing pollution sites

    International Nuclear Information System (INIS)

    Wichmann, H.E.; Wuppertal Univ.; Ihme, W.; Mekel, O.C.L.; Wuppertal Univ.

    1993-01-01

    The project attempts a quantitative assessment of risks for three carcinogenics that are common in sites of long-standing pollution. Benzo(a)pyrene stands for the group of polycyclic aromatic hydrocarbons, cadmium for heavy metals, and benzene for volatile aromatic compounds. The report discusses the general fundamentals of exposure and risk assessment. The exposure model is described in detail and applied to the three test substances. (orig./MG) [de

  10. Modelling exposure of mammalian predators to anticoagulant rodenticide

    Directory of Open Access Journals (Sweden)

    Christopher John Topping

    2016-12-01

    Full Text Available Anticoagulant rodenticides (AR are a widespread and effective method of rodent control but there is concern about the impact these may have on non-target organisms, in particular secondary poisoning of rodent predators. Incidence and concentration of AR in free-living predators in Denmark is very high. We postulate that this is caused by widespread exposure due to widespread use of AR in Denmark in and around buildings. To investigate this theory a spatio-temporal model of AR use and mammalian predator distribution was created. This model was supported by data from an experimental study of mice as vectors of AR, and was used to evaluate likely impacts of restrictions imposed on AR use in Denmark banning the use of rodenticides for plant protection in woodlands and tree-crops. The model uses input based on frequencies and timings of baiting for rodent control for urban, rural and woodland locations and creates an exposure map based on spatio-temporal modelling of movement of mice-vectored AR (based on Apodemus flavicollis. Simulated predator territories are super-imposed over this exposure map to create an exposure index. Predictions from the model concur with field studies of AR prevalence both before and after the change in AR use. In most cases incidence of exposure to AR is predicted to be greater than 90%, although cessation of use in woodlots and Christmas tree plantations should reduce mean exposure concentrations. Model results suggest that the driver of high AR incidence in non-target small mammal predators is likely to be the pattern of use and not the distance AR is vectored. Reducing baiting frequency by 75% had different effects depending on the landscape simulated, but having a maximum of 12% reduction in exposure incidence, and in one landscape a maximum reduction of <2%. We discuss sources of uncertainty in the model and directions for future development of predictive models for environmental impact assessment of rodenticides. The

  11. Determining the validity of exposure models for environmental epidemiology : predicting electromagnetic fields from mobile phone base stations

    NARCIS (Netherlands)

    Beekhuizen, Johan|info:eu-repo/dai/nl/34472641X

    2014-01-01

    One of the key challenges in environmental epidemiology is the exposure assessment of large populations. Spatial exposure models have been developed that predict exposure to the pollutant of interest for large study sizes. However, the validity of these exposure models is often unknown. In this

  12. Nutrition: assessment of human exposure to environment

    International Nuclear Information System (INIS)

    Zaini Hamzah; Zuraidah Abdullah Munir; Suziana Ismail; Abd Khalik Wood; Suhaimi Hamzah; Syamsiah Abdul Rahman; Wee Boon Siong; Suhaimi Alias; Nazatul Ashita Abdullah Salim

    2004-01-01

    The objectives of the research are (I) to determine the essential and toxic elements in foodstuffs, (II) to study the sufficient elemental levels in foodstuff for the dietary intake, (III) to assess the relationship of the essential and toxic elements intake to the types of diet and (IV) to compare the food quality of Malaysian various cuisine on essential and toxic elements

  13. Econometric model for age- and population-dependent radiation exposures

    International Nuclear Information System (INIS)

    Sandquist, G.M.; Slaughter, D.M.; Rogers, V.C.

    1991-01-01

    The economic impact associated with ionizing radiation exposures in a given human population depends on numerous factors including the individual's mean economic status as a function age, the age distribution of the population, the future life expectancy at each age, and the latency period for the occurrence of radiation-induced health effects. A simple mathematical model has been developed that provides an analytical methodology for estimating the societal econometrics associated with radiation effects are to be assessed and compared for economic evaluation

  14. Spatial and Temporal Dynamics in Air Pollution Exposure Assessment

    Science.gov (United States)

    Dias, Daniela; Tchepel, Oxana

    2018-01-01

    Analyzing individual exposure in urban areas offers several challenges where both the individual’s activities and air pollution levels demonstrate a large degree of spatial and temporal dynamics. This review article discusses the concepts, key elements, current developments in assessing personal exposure to urban air pollution (seventy-two studies reviewed) and respective advantages and disadvantages. A new conceptual structure to organize personal exposure assessment methods is proposed according to two classification criteria: (i) spatial-temporal variations of individuals’ activities (point-fixed or trajectory based) and (ii) characterization of air quality (variable or uniform). This review suggests that the spatial and temporal variability of urban air pollution levels in combination with indoor exposures and individual’s time-activity patterns are key elements of personal exposure assessment. In the literature review, the majority of revised studies (44 studies) indicate that the trajectory based with variable air quality approach provides a promising framework for tackling the important question of inter- and intra-variability of individual exposure. However, future quantitative comparison between the different approaches should be performed, and the selection of the most appropriate approach for exposure quantification should take into account the purpose of the health study. This review provides a structured basis for the intercomparing of different methodologies and to make their advantages and limitations more transparent in addressing specific research objectives. PMID:29558426

  15. Retrospective internal radiation exposure assessment in occupational epidemiology

    International Nuclear Information System (INIS)

    Neton, J.W.; Flora, J.T.; Spitz, H.B.; Taulbee, T.D.

    2000-01-01

    Epidemiologic studies of workers at U.S. Department of Energy facilities are being conducted by the U.S. National Institute for Occupational Safety and Health to evaluate the health risk associated with exposure to sources of external and internal ionizing radiation. While exposure to external sources of radiation can be estimated from personal dosimeter data, reconstruction of exposure due to internally deposited radioactivity is more challenging because bioassay monitoring data is frequently less complete. Although comprehensive monitoring was provided for workers with the highest internal exposures, the majority of workers were monitored relatively infrequently. This monitoring was conducted to demonstrate compliance with regulations rather than to evaluate exposure for use in epidemiologic studies. Attributes of past internal monitoring programs that challenge accurate exposure assessment include: incomplete characterization of the workplace source term; a lack of timely measurements; insensitive and/or nonspecific bioassay measurements; and the presence of censored data. In spite of these limitations, many facilities have collected a large amount of worker and workplace monitoring information that can be used to evaluate internal exposure while minimizing worker misclassification. This paper describes a systematic approach for using the available worker and workplace monitoring data that can lead to either a qualitative or quantitative retrospective assessment of internal exposures. Various aspects of data analysis will be presented, including the evaluation of minimum detectable dose, the treatment of censored data, and the use of combinations of bioassay and workplace data to characterize exposures. Examples of these techniques applied to a cohort study involving chronic exposure scenarios to uranium are provided. A strategy for expressing exposure or dose in fundamental, unweighted units related to the quantity of radiation delivered to an organ will also

  16. Range-finding risk assessment of inhalation exposure to nanodiamonds in a laboratory environment.

    Science.gov (United States)

    Koivisto, Antti J; Palomäki, Jaana E; Viitanen, Anna-Kaisa; Siivola, Kirsi M; Koponen, Ismo K; Yu, Mingzhou; Kanerva, Tomi S; Norppa, Hannu; Alenius, Harri T; Hussein, Tareq; Savolainen, Kai M; Hämeri, Kaarle J

    2014-05-16

    This study considers fundamental methods in occupational risk assessment of exposure to airborne engineered nanomaterials. We discuss characterization of particle emissions, exposure assessment, hazard assessment with in vitro studies, and risk range characterization using calculated inhaled doses and dose-response translated to humans from in vitro studies. Here, the methods were utilized to assess workers' risk range of inhalation exposure to nanodiamonds (NDs) during handling and sieving of ND powder. NDs were agglomerated to over 500 nm particles, and mean exposure levels of different work tasks varied from 0.24 to 4.96 µg·m(-3) (0.08 to 0.74 cm(-3)). In vitro-experiments suggested that ND exposure may cause a risk for activation of inflammatory cascade. However, risk range characterization based on in vitro dose-response was not performed because accurate assessment of delivered (settled) dose on the cells was not possible. Comparison of ND exposure with common pollutants revealed that ND exposure was below 5 μg·m(-3), which is one of the proposed exposure limits for diesel particulate matter, and the workers' calculated dose of NDs during the measurement day was 74 ng which corresponded to 0.02% of the modeled daily (24 h) dose of submicrometer urban air particles.

  17. Range-Finding Risk Assessment of Inhalation Exposure to Nanodiamonds in a Laboratory Environment

    Directory of Open Access Journals (Sweden)

    Antti J. Koivisto

    2014-05-01

    Full Text Available This study considers fundamental methods in occupational risk assessment of exposure to airborne engineered nanomaterials. We discuss characterization of particle emissions, exposure assessment, hazard assessment with in vitro studies, and risk range characterization using calculated inhaled doses and dose-response translated to humans from in vitro studies. Here, the methods were utilized to assess workers’ risk range of inhalation exposure to nanodiamonds (NDs during handling and sieving of ND powder. NDs were agglomerated to over 500 nm particles, and mean exposure levels of different work tasks varied from 0.24 to 4.96 µg·m−3 (0.08 to 0.74 cm−3. In vitro-experiments suggested that ND exposure may cause a risk for activation of inflammatory cascade. However, risk range characterization based on in vitro dose-response was not performed because accurate assessment of delivered (settled dose on the cells was not possible. Comparison of ND exposure with common pollutants revealed that ND exposure was below 5 μg·m−3, which is one of the proposed exposure limits for diesel particulate matter, and the workers’ calculated dose of NDs during the measurement day was 74 ng which corresponded to 0.02% of the modeled daily (24 h dose of submicrometer urban air particles.

  18. Sensitivity Analysis of Personal Exposure Assessment Using a Computer Simulated Person

    DEFF Research Database (Denmark)

    Brohus, Henrik; Jensen, H. K.

    2009-01-01

    The paper considers uncertainties related to personal exposure assessment using a computer simulated person. CFD is used to simulate a uniform flow field around a human being to determine the personal exposure to a contaminant source. For various vertical locations of a point contaminant source...... three additional factors are varied, namely the velocity, details of the computer simulated person, and the CFD model of the wind channel. The personal exposure is found to be highly dependent on the relative source location. Variation in the range of two orders of magnitude is found. The exposure...

  19. External exposure assessment in dwelling built with phosphogypsum

    International Nuclear Information System (INIS)

    Villaverde, Freddy Lazo

    2008-01-01

    In this study it was evaluated the viability of the use of phosphogypsum plates as a building material in the dwelling construction. Thus, the effective dose due to external gamma exposure was assessed through the 226 Ra, 232 Th, 210 Pb e 40 K activity concentration in phosphogypsum plates. Samples of this material were analyzed by high resolution gamma spectrometry for their natural radionuclide activity concentration. The radium equivalent activity and extern ai and inter nai hazard indices were also calculated. The plates were made with phosphogypsum from fertilizer industries located in Cajati, Cubatao and Uberaba. The samples were identified according to phosphogypsum origin, Cajati (CA), Cubatao (CT) and Uberaba (UB). The activity concentrations results varied from 15.9 to 392 Bq kg -1 for 226 Ra, 26.1 to 253 Bq kg -1 for 232 Th, and 27.4 to 852 Bq kg -1 for 210 Pb. The results of 40 K were lower than 81 Bq kg -1 . The annual effective dose was obtained through the dosimetric model with reference standard room concept, the results were 0.02 mSv y -1 for a house built with phosphogypsum from origin CA, 0.2 mSvy -1 for CT phosphogypsum and 0.14 mSvy -1 for UB phosphogypsum, everything the effective doses were below 1 mSvy -1 , an annual effective dose limit for public exposure by International Commission on Radiological Protection. (author)

  20. #2 - An Empirical Assessment of Exposure Measurement Error ...

    Science.gov (United States)

    Background• Differing degrees of exposure error acrosspollutants• Previous focus on quantifying and accounting forexposure error in single-pollutant models• Examine exposure errors for multiple pollutantsand provide insights on the potential for bias andattenuation of effect estimates in single and bipollutantepidemiological models The National Exposure Research Laboratory (NERL) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA mission to protect human health and the environment. HEASD research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processes that link source emissions, environmental concentrations, human exposures, and target-tissue dose. The impact of these tools is improved regulatory programs and policies for EPA.

  1. EXPOSURE ANALYSIS MODELING SYSTEM (EXAMS): USER MANUAL AND SYSTEM DOCUMENTATION

    Science.gov (United States)

    The Exposure Analysis Modeling System, first published in 1982 (EPA-600/3-82-023), provides interactive computer software for formulating aquatic ecosystem models and rapidly evaluating the fate, transport, and exposure concentrations of synthetic organic chemicals - pesticides, ...

  2. Assessing exposure to cosmic radiation aboard aircraft: the SIEVERT system

    International Nuclear Information System (INIS)

    Bottolier-Depois, J.F.; Clairand, I.; Blanchard, P.; Dessarps, P.; Lantos, P.

    2005-01-01

    Full text: The study of naturally-occurring radiation and its associated risk is one of the preoccupations of bodies responsible for radiation protection. Cosmic particle flux is significantly higher on board aircraft that at ground level. Furthermore, its intensity depends on solar activity and eruptions. Due to their professional activity, flight crews and frequent flyers may receive an annual dose of some milliSieverts. This is why the European directive adopted in 1996 requires the aircraft operators to assess the dose and to inform their flight crews about the risk. The effective dose is to be estimated using various experimental and calculation means. In France, the computerized system for flight assessment of exposure to cosmic radiation in air transport (SIEVERT) is delivered to airlines for assisting them in the application of the European directive. This dose assessment tool was developed by the French General Directorate of Civil Aviation (DGAC) and partners: the Institute for Radiation Protection and Nuclear Safety (IRSN), the Paris Observatory and the French Institute for Polar Research - PaulEmile Victor (IPEV). This professional service is available since more than two years on an Internet server accessible to companies with a public section. The system provides doses that consider the routes flown by aircraft. Various results obtained are presented: experimental validation, in particular for the ground level event model (large solar eruption), and statistics on routes and personal doses. (author)

  3. Exposure assessment strategies for non-routine work operations (NORWO)

    International Nuclear Information System (INIS)

    Lew, V.; Cohen, J.; Chiusano, S.; McGann, C.; McLouth, L.

    1993-09-01

    The DOE Office of Health and Office of Safety and Health Oversight are collaborating to address special problems related to assessment of worker exposures associated with nonroutine work operations (NORWO), such as hazardous waste operations. Both off ices have formed a single working group of industrial hygiene specialists from the DOE, fts contractors, and other interested organizations which held its first meeting July 1993. The DOE Canter of Excellence for Exposure Assessment, maintained at Lawrence Livermore National Laboratory, is assisting in developing reasonable policies and guidance on exposure assessment strategies for NORWO. The DOE EA Center will research this subject to assist the DOE in formulating guidance documents for conduct of EA for NORWO that are consistent with the DOE draft EAS technical standard. This report presents an outline for a section on NORWO intended for inclusion in the DOE technical guidance documents for EAS and Hazardous Waste Operations Emergency Response (HAZWOPER) currently under development by the DOE Industrial Hygiene Division (EH-412), and EM-23. Also presented is a review of the July 21--23 meeting and a proposed workplan for developing NORWO exposure assessment procedures. Appendices include: (A) David Weitzman's memo on NORWO, (B) Draft annotated outline of the technical standard for the Assessment of Employee Exposure to Hazardous Chemical Agents, (C) ORC proposed EAS standard, (D) program for the October 31--November 3, 1993 ACGIH Conference on Occupational Exposure Databases, (E) agenda for the July 15, 1993 DOE meeting on NORWO, (F) viewgraphs used in formal presentations at this meeting, (G) Hanford Exposure Assessment Program Plan, and (H) a list of attendees and invitees to the July DOE -- NORWO meeting

  4. Assessment of Industrial Exposure to Magnetic Fields (invited paper)

    International Nuclear Information System (INIS)

    Chadwick, P.

    1999-01-01

    Magnetic field strengths produced by industrial processes can be very large, but they often exhibit a marked spatial variation. Whilst there may be the potential for exposures of workers to be high, actual exposure will be determined to a great extent by working practices. Possible metrics for epidemiological studies might be based on the temporal variability of exposure as well as maximum operator exposure or time-weighted average exposure and, whilst it might be possible to estimate these quantities from spot magnetic field strength measurements and observed working practices, this might be very difficult to achieve in practice. An alternative would be the use of a logging dosemeter: this paper describes some of the results of exposure assessments carried out in industrial environments with a modified EMDEX II magnetic field dosemeter. Magnetic fields in industrial environments often have waveforms which are not purely sinusoidal. Distortion can be introduced by the magnetic saturation of transformer and motor cores, by rectification, by poor matching between oscillator circuits and loads and when thyristors are used to control power. The resulting repetitive but non-sinusoidal magnetic field waveforms can be recorded and analysed; the spectral data may be incorporated into possible exposure metrics. It is also important to ensure that measurement instrumentation is responding appropriately in a non-sinusoidal field and this can only be done if the spectral content of the field is characterised fully. Some non-sinusoidal magnetic field waveforms cannot be expressed as a harmonic series. Specialist instrumentation and techniques are needed to assess exposure to such fields. Examples of approaches to the assessment of exposure to repetitive and non-repetitive magnetic fields are also discussed. (author)

  5. Assessing global exposure and vulnerability towards natural hazards: the Disaster Risk Index

    Directory of Open Access Journals (Sweden)

    P. Peduzzi

    2009-07-01

    Full Text Available This paper presents a model of factors influencing levels of human losses from natural hazards at the global scale, for the period 1980–2000. This model was designed for the United Nations Development Programme as a building stone of the Disaster Risk Index (DRI, which aims at monitoring the evolution of risk. Assessing what countries are most at risk requires considering various types of hazards, such as droughts, floods, cyclones and earthquakes. Before assessing risk, these four hazards were modelled using GIS and overlaid with a model of population distribution in order to extract human exposure. Human vulnerability was measured by crossing exposure with selected socio-economic parameters. The model evaluates to what extent observed past losses are related to population exposure and vulnerability. Results reveal that human vulnerability is mostly linked with country development level and environmental quality. A classification of countries is provided, as well as recommendations on data improvement for future use of the model.

  6. Modeling Exposure of Mammalian Predatorsto Anticoagulant Rodenticides

    DEFF Research Database (Denmark)

    Topping, Christopher John; Elmeros, Morten

    2016-01-01

    as vectors of AR, and was used to evaluate likely impacts of restrictions imposed on AR use in Denmark banning the use of rodenticides for plant protection in woodlands and tree-crops. The model uses input based on frequencies and timings of baiting for rodent control for urban, rural and woodland locations......Anticoagulant rodenticides (AR) are a widespread and effective method of rodent control but there is concern about the impact these may have on non-target organisms, in particular secondary poisoning of rodent predators. Incidence and concentration of AR in free-living predators in Denmark is very...... high. We postulate that this is caused by widespread exposure due to widespread use of AR in Denmark in and around buildings. To investigate this theory a spatio-temporal model of AR use and mammalian predator distribution was created. This model was supported by data from an experimental study of mice...

  7. Scientific Opinion on outline proposals for assessment of exposure of organisms to substances in soil

    DEFF Research Database (Denmark)

    Petersen, Annette

    2010-01-01

    appropriate for both conventional and reduced tillage in multi-year exposure calculations. The Panel proposes a tiered exposure assessment approach with four tiers. Tier 1 consists of a simple analytical model. Tier 2 consists of three scenarios (one for each of the three regulatory zones) that can be used...... for any annual crop in a zone. In Tiers 3 and 4, the exposure assessment can be refined considering the specific crops and/or substances with specific properties. The Panel proposes to develop guidance for estimating the degradation rate within the soil matrix from field persistence studies...

  8. Control banding tools for occupational exposure assessment of nanomaterials - Ready for use in a regulatory context?

    DEFF Research Database (Denmark)

    Liguori, Biase; Hansen, Steffen Foss; Baun, Anders

    2016-01-01

    area of concern. Therefore, a number of Control Banding (CB)-based tools have been developed in order to assess and manage the potential risks associated with occupational exposure to nanomaterials. In this paper we provide a comparative analysis of different nanomaterial-specific types of control-banding/risk...... developed for different purposes, with different application domains and inclusion criteria. The exposure assessments and derived risk levels are based on different concepts and assumptions and outputs in different formats. The use of requested input parameters for exposure assessment differ greatly among...... the tools. Therefore, direct inter-comparison and combination of the different models into a larger holistic framework is not immediately possible. Harmonization of input parameters and output could allow establishment of an exposure assessment framework with different levels of information requirements....

  9. Pesticide Flow Analysis to Assess Human Exposure in Greenhouse Flower Production in Colombia

    Directory of Open Access Journals (Sweden)

    Claudia R. Binder

    2013-03-01

    Full Text Available Human exposure assessment tools represent a means for understanding human exposure to pesticides in agricultural activities and managing possible health risks. This paper presents a pesticide flow analysis modeling approach developed to assess human exposure to pesticide use in greenhouse flower crops in Colombia, focusing on dermal and inhalation exposure. This approach is based on the material flow analysis methodology. The transfer coefficients were obtained using the whole body dosimetry method for dermal exposure and the button personal inhalable aerosol sampler for inhalation exposure, using the tracer uranine as a pesticide surrogate. The case study was a greenhouse rose farm in the Bogota Plateau in Colombia. The approach was applied to estimate the exposure to pesticides such as mancozeb, carbendazim, propamocarb hydrochloride, fosetyl, carboxin, thiram, dimethomorph and mandipropamide. We found dermal absorption estimations close to the AOEL reference values for the pesticides carbendazim, mancozeb, thiram and mandipropamide during the study period. In addition, high values of dermal exposure were found on the forearms, hands, chest and legs of study participants, indicating weaknesses in the overlapping areas of the personal protective equipment parts. These results show how the material flow analysis methodology can be applied in the field of human exposure for early recognition of the dispersion of pesticides and support the development of measures to improve operational safety during pesticide management. Furthermore, the model makes it possible to identify the status quo of the health risk faced by workers in the study area.

  10. Using cell phone location to assess misclassification errors in air pollution exposure estimation.

    Science.gov (United States)

    Yu, Haofei; Russell, Armistead; Mulholland, James; Huang, Zhijiong

    2018-02-01

    Air pollution epidemiologic and health impact studies often rely on home addresses to estimate individual subject's pollution exposure. In this study, we used detailed cell phone location data, the call detail record (CDR), to account for the impact of spatiotemporal subject mobility on estimates of ambient air pollutant exposure. This approach was applied on a sample with 9886 unique simcard IDs in Shenzhen, China, on one mid-week day in October 2013. Hourly ambient concentrations of six chosen pollutants were simulated by the Community Multi-scale Air Quality model fused with observational data, and matched with detailed location data for these IDs. The results were compared with exposure estimates using home addresses to assess potential exposure misclassification errors. We found the misclassifications errors are likely to be substantial when home location alone is applied. The CDR based approach indicates that the home based approach tends to over-estimate exposures for subjects with higher exposure levels and under-estimate exposures for those with lower exposure levels. Our results show that the cell phone location based approach can be used to assess exposure misclassification error and has the potential for improving exposure estimates in air pollution epidemiology studies. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. The Future of Exposure Assessment: Perspectives from the ...

    Science.gov (United States)

    The British Occupational Hygiene Society, in collaboration with the Institute of Occupational Medicine, the University of Manchester, the UK Health and Safety Executive, and the University of Aberdeen hosted the 7th International Conference on the Science of Exposure Assessment (X2012) on 2 July–5 July 2012 in Edinburgh, UK. The conference ended with a special session at which invited speakers from government, industry, independent research institutes, and academia were asked to reflect on the conference and discuss what may now constitute the important highlights or drivers of future exposure assessment research. This article summarizes these discussions with respect to current and future technical and methodological developments. For the exposure science community to continue to have an impact in protecting public health, additional efforts need to be made to improve partnerships and cross-disciplinary collaborations, although it is equally important to ensure that the traditional occupational exposure themes are still covered as these issues are becoming increasingly important in the developing world. To facilitate this the ‘X’ conferences should continue to retain a holistic approach to occupational and non-occupational exposures and should actively pursue collaborations with other disciplines and professional organizations to increase the presence of consumer and environmental exposure scientists. The National Exposure Research Laboratory′s (NERL′

  12. Integrating exposure into chemical alternatives assessment using a qualitative approach

    DEFF Research Database (Denmark)

    Greggs, Bill; Arnold, Scott; Burns, T. E.

    2016-01-01

    , other attributes beyond hazard are also important, including exposure, risk, life-cycle impacts, performance, cost, and social responsibility. Building on the 2014 recommendations by the U.S. National Academy of Sciences to improve AA decisions by including comparative exposure assessment, the HESI...... Sustainable Chemical Alternatives Technical Committee, which consists of scientists from academia, industry, government, and NGOs, has developed a qualitative comparative exposure approach. Conducting such a comparison can screen for alternatives that are expected to have a higher human or environmental...... not necessarily reflect the views or policies of the U.S. Environmental Protection Agency....

  13. A Spatial Model of the Mere Exposure Effect.

    Science.gov (United States)

    Fink, Edward L.; And Others

    1989-01-01

    Uses a spatial model to examine the relationship between stimulus exposure, cognition, and affect. Notes that this model accounts for cognitive changes that a stimulus may acquire as a result of exposure. Concludes that the spatial model is useful for evaluating the mere exposure effect and that affective change does not require cognitive change.…

  14. Assessment of occupational exposure to gaseous peracetic acid.

    Science.gov (United States)

    Dugheri, Stefano; Bonari, Alessandro; Pompilio, Ilenia; Colpo, Marco; Montalti, Manfredi; Mucci, Nicola; Arcangeli, Giulio

    2018-02-07

    In order to assess short-term exposure to peracetic acid (PAA) in disinfection processes, the Authors compared 4 industrial hygiene monitoring methods to evaluate their proficiency in measuring airborne PAA concentrations. An active sampling by basic silica gel impregnated with methyl p-tolyl sulfoxide (MTSO), a passive solid phase micro-extraction technique using methyl p-tolyl sulfide (MTS) as on-fiber derivatization reagent, an electrochemical direct-reading PAA monitor, and a novel visual test strip PAA detector doped with 2,2'-azino-bis (3-ethylbenzothiazoline)-6-sulfonate were evaluated and tested over the range of 0.06-16 mg/m3, using dynamically generated PAA air concentrations. The linear regression analysis of linearity and accuracy showed that the 4 methods were suitable for PAA monitoring. Peracetic acid monitoring in several use applications showed that the PAA concentration (1.8 mg/m3) was immediately dangerous to life or health as proposed by the National Institute of Occupational Safety and Health, and was frequently exceeded in wastewater treatment (up to 7.33 mg/m3), and sometimes during food and beverage processes and hospital high-level disinfection operations (up to 6.8 mg/m3). The methods were suitable for the quick assessment of acute exposure in PAA environmental monitoring and can assist in improving safety and air quality in the workplace where this disinfectant is used. These monitoring methods allowed the evaluation of changes to work out practices to reduce PAA vapor concentrations during the operations when workers are potentially overexposed to this strong antioxidant agent. This work is available in Open Access model and licensed under a CC BY-NC 3.0 PL license.

  15. A Review of Exposure Assessment Methods in Epidemiological Studies on Incinerators

    Directory of Open Access Journals (Sweden)

    Michele Cordioli

    2013-01-01

    Full Text Available Incineration is a common technology for waste disposal, and there is public concern for the health impact deriving from incinerators. Poor exposure assessment has been claimed as one of the main causes of inconsistency in the epidemiological literature. We reviewed 41 studies on incinerators published between 1984 and January 2013 and classified them on the basis of exposure assessment approach. Moreover, we performed a simulation study to explore how the different exposure metrics may influence the exposure levels used in epidemiological studies. 19 studies used linear distance as a measure of exposure to incinerators, 11 studies atmospheric dispersion models, and the remaining 11 studies a qualitative variable such as presence/absence of the source. All reviewed studies utilized residence as a proxy for population exposure, although residence location was evaluated with different precision (e.g., municipality, census block, or exact address. Only one study reconstructed temporal variability in exposure. Our simulation study showed a notable degree of exposure misclassification caused by the use of distance compared to dispersion modelling. We suggest that future studies (i make full use of pollution dispersion models; (ii localize population on a fine-scale; and (iii explicitly account for the presence of potential environmental and socioeconomic confounding.

  16. Conceptual Framework To Extend Life Cycle Assessment Using Near-Field Human Exposure Modeling and High-Throughput Tools for Chemicals

    Science.gov (United States)

    Life Cycle Assessment (LCA) is a decision-making tool that accounts for multiple impacts across the life cycle of a product or service. This paper presents a conceptual framework to integrate human health impact assessment with risk screening approaches to extend LCA to include n...

  17. Assessment of health impacts of radon exposures in Florida

    International Nuclear Information System (INIS)

    Vonstille, W.T.; Sacarello, H.L.A.

    1990-01-01

    This paper reports on residential radon levels, from a statewide Florida survey, that were used in an analysis of over 150,000 medically treated episodes of malignancies and other serious illnesses and conditions in whites, blacks and Hispanics from all counties in the state. No evidence of an increased percentage of cancer was found in any sex or ethnic group from the areas with the highest radon exposure levels. Age adjustment of data did not affect the results. The highest radon exposures were associated with some of the lowest cancer rates and contradict the risk assessment hypothesis based on extrapolation from exposures in mining. Points for DOE and EPA errors in risk assessment methods are reviewed; predictions from risk assessment should be empirically tested as in the case of any other scientific hypothesis before being used as a basis for public policy. Thus, the authors find that cancer risks of residential radon have been vastly overstated

  18. Occupational Exposure Assessment of Nanomaterials using Control Banding Tools

    DEFF Research Database (Denmark)

    Liguori, Biase

    , are relatively advanced, and they are good foundations for an advanced exposure assessment. Considering the tiered approach for workplace assessment proposed by the OECD, these two tools could be situated, between Tier 1 (Information gathering) and Tier 2 (Basic exposure assessment). Moreover, the thesis......Nanotechnology can be termed as the “new industrial revolution”. A broad range of potential benefits in various applications for the environment and everyday life of humans can be related to the use of nanotechnology. Nanomaterials are used in a large variety of products already in the market......, and because of their novel physical and chemical characteristics, the application of nanomaterials is projected to increase further. This will inevitably increase the production of nanomaterials with potential increase of exposure for the workers which are the first in line expected to become exposed...

  19. Human exposure to bisphenol A by biomonitoring: Methods, results and assessment of environmental exposures

    International Nuclear Information System (INIS)

    Dekant, Wolfgang; Voelkel, Wolfgang

    2008-01-01

    Human exposure to bisphenol A is controversially discussed. This review critically assesses methods for biomonitoring of bisphenol A exposures and reported concentrations of bisphenol A in blood and urine of non-occupationally ('environmentally') exposed humans. From the many methods published to assess bisphenol A concentrations in biological media, mass spectrometry-based methods are considered most appropriate due to high sensitivity, selectivity and precision. In human blood, based on the known toxicokinetics of bisphenol A in humans, the expected very low concentrations of bisphenol A due to rapid biotransformation and the very rapid excretion result in severe limitations in the use of reported blood levels of bisphenol A for exposure assessment. Due to the rapid and complete excretion of orally administered bisphenol A, urine samples are considered as the appropriate body fluid for bisphenol A exposure assessment. In urine samples from several cohorts, bisphenol A (as glucuronide) was present in average concentrations in the range of 1-3 μg/L suggesting that daily human exposure to bisphenol A is below 6 μg per person (< 0.1 μg/kg bw/day) for the majority of the population

  20. A Formaldehyde Exposure Assessment Tool for Occupants of FEMA Temporary Housing Units

    Energy Technology Data Exchange (ETDEWEB)

    Parthasarathy, Srinandini; Spears, Michael; Maddalena, Randy L.; Russell, Marion L; Apte, Michael G.

    2010-10-01

    The report outlines the methodology used to develop a web-based tool to assess the formaldehyde exposure of the occupants of Federal Emergency Management Administration (FEMA) temporary housing units (THUs) after Hurricanes Katrina and Rita in 2005. Linear regression models were built using available data to retrospectively estimate the indoor temperature and relative humidity, formaldehyde emission factors and concentration, and hence the formaldehyde exposures. The interactive web-tool allows the user to define the inputs to the model to evaluate formaldehyde exposures for different scenarios.

  1. Stakeholder attitudes towards cumulative and aggregate exposure assessment of pesticides.

    Science.gov (United States)

    Verbeke, Wim; Van Loo, Ellen J; Vanhonacker, Filiep; Delcour, Ilse; Spanoghe, Pieter; van Klaveren, Jacob D

    2015-05-01

    This study evaluates the attitudes and perspectives of different stakeholder groups (agricultural producers, pesticide manufacturers, trading companies, retailers, regulators, food safety authorities, scientists and NGOs) towards the concepts of cumulative and aggregate exposure assessment of pesticides by means of qualitative in-depth interviews (n = 15) and a quantitative stakeholder survey (n = 65). The stakeholders involved generally agreed that the use of chemical pesticides is needed, primarily for meeting the need of feeding the growing world population, while clearly acknowledging the problematic nature of human exposure to pesticide residues. Current monitoring was generally perceived to be adequate, but the timeliness and consistency of monitoring practices across countries were questioned. The concept of cumulative exposure assessment was better understood by stakeholders than the concept of aggregate exposure assessment. Identified pitfalls were data availability, data limitations, sources and ways of dealing with uncertainties, as well as information and training needs. Regulators and food safety authorities were perceived as the stakeholder groups for whom cumulative and aggregate pesticide exposure assessment methods and tools would be most useful and acceptable. Insights obtained from this exploratory study have been integrated in the development of targeted and stakeholder-tailored dissemination and training programmes that were implemented within the EU-FP7 project ACROPOLIS. Copyright © 2014 Elsevier Ltd. All rights reserved.

  2. The multimedia models for the evaluation of exposure bond to the atmospheric emissions of classified installations

    International Nuclear Information System (INIS)

    Bonnard, R.

    2001-12-01

    Risk assessment and environmental impacts studies are realized to preserve the public health. Today one of the most used approach is the use of an atmospheric dispersion model to assess the risks. The data are then injected in a calculation software of exposure bond to polluted soils, to evaluate the risks of non direct exposure. This report details and evaluates the models corresponding to the need: the methodology for assessing Health Risks associated with multiple pathways of exposure to combustor, human health risk assessment proto col for hazardous waste combustion facilities, EUSES, CALTOX, MEPAS, MEND-TOX, RESRAD, MMSOILS, FRAMES-HWIR, PC-GEMS and TRIM. (A.L.B.)

  3. Real-time assessment of exposure dose to workers in radiological environments during decommissioning of nuclear facilities

    International Nuclear Information System (INIS)

    Jeong, KwanSeong; Choi, ByungSeon; Moon, JeiKwon; Hyun, Dongjun; Lee, Jonghwan; Kim, IkJune; Kim, GeunHo; Seo, JaeSeok; Jeong, SeongYoung; Lee, JungJun; Song, HaeSang; Lee, SangWha; Son, BongKi

    2014-01-01

    Highlights: • The method of exposure dose assessment to workers during decommissioning of nuclear facilities. • The environments of simulation were designed under a virtual reality. • To assess exposure dose to workers, human model was developed within a virtual reality. - Abstract: This objective of this paper is to develop a method to simulate and assess the exposure dose to workers during decommissioning of nuclear facilities. To simulate several scenarios, decommissioning environments were designed using virtual reality. To assess exposure dose to workers, a human model was also developed using virtual reality. The exposure dose was measured and assessed under the principle of ALARA in accordance with radiological environmental change. This method will make it possible to plan for the exposure dose to workers during decommissioning of nuclear facilities

  4. Comparison of modeled estimates of inhalation exposure to aerosols during use of consumer spray products.

    Science.gov (United States)

    Park, Jihoon; Yoon, Chungsik; Lee, Kiyoung

    2018-05-30

    In the field of exposure science, various exposure assessment models have been developed to complement experimental measurements; however, few studies have been published on their validity. This study compares the estimated inhaled aerosol doses of several inhalation exposure models to experimental measurements of aerosols released from consumer spray products, and then compares deposited doses within different parts of the human respiratory tract according to deposition models. Exposure models, including the European Center for Ecotoxicology of Chemicals Targeted Risk Assessment (ECETOC TRA), the Consumer Exposure Model (CEM), SprayExpo, ConsExpo Web and ConsExpo Nano, were used to estimate the inhaled dose under various exposure scenarios, and modeled and experimental estimates were compared. The deposited dose in different respiratory regions was estimated using the International Commission on Radiological Protection model and multiple-path particle dosimetry models under the assumption of polydispersed particles. The modeled estimates of the inhaled doses were accurate in the short term, i.e., within 10 min of the initial spraying, with a differences from experimental estimates ranging from 0 to 73% among the models. However, the estimates for long-term exposure, i.e., exposure times of several hours, deviated significantly from the experimental estimates in the absence of ventilation. The differences between the experimental and modeled estimates of particle number and surface area were constant over time under ventilated conditions. ConsExpo Nano, as a nano-scale model, showed stable estimates of short-term exposure, with a difference from the experimental estimates of less than 60% for all metrics. The deposited particle estimates were similar among the deposition models, particularly in the nanoparticle range for the head airway and alveolar regions. In conclusion, the results showed that the inhalation exposure models tested in this study are suitable

  5. Non-ionizing electromagnetic exposure assessment and dosimetry

    International Nuclear Information System (INIS)

    Paulsson, L.E.

    1992-11-01

    A comprehensive literature survey of advancements in the area 'human exposure assessment and dosimetry' for the years 1988-1992 has been performed by the author and published elsewhere. In the present report that material has been complemented with a historical background and a thorough description of the physical principles behind the methods and techniques. The report covers strategies, principles, methods, limitations and future developments for the area of human exposure assessment and dosimetry of electromagnetic fields form extremely low frequencies up to and including microwaves

  6. Biocides Steering Group on human exposure assessment: a preliminary report.

    Science.gov (United States)

    van Hemmen, J J

    1999-06-30

    In a project granted by DG XI of the European Commission, it is attempted to collate experimental and theoretical data on human (workers and consumers) exposure assessment to biocidal products, and to outline the methodology for sampling and measurement. On the basis of the available evidence, approaches are presented for the exposure assessment to be used for estimation of risks in authorization procedures under the recently accepted Directive 98/8/EC. Gaps in knowledge are indicated, making it possible to study the issues involved in a comprehensive and cost-effective way. Some recommendations are given on how to best do this. The current project has been detailed in a final report.

  7. Task-based exposure assessment of nanoparticles in the workplace

    International Nuclear Information System (INIS)

    Ham, Seunghon; Yoon, Chungsik; Lee, Euiseung; Lee, Kiyoung; Park, Donguk; Chung, Eunkyo; Kim, Pilje; Lee, Byoungcheun

    2012-01-01

    Although task-based sampling is, theoretically, a plausible approach to the assessment of nanoparticle exposure, few studies using this type of sampling have been published. This study characterized and compared task-based nanoparticle exposure profiles for engineered nanoparticle manufacturing workplaces (ENMW) and workplaces that generated welding fumes containing incidental nanoparticles. Two ENMW and two welding workplaces were selected for exposure assessments. Real-time devices were utilized to characterize the concentration profiles and size distributions of airborne nanoparticles. Filter-based sampling was performed to measure time-weighted average (TWA) concentrations, and off-line analysis was performed using an electron microscope. Workplace tasks were recorded by researchers to determine the concentration profiles associated with particular tasks/events. This study demonstrated that exposure profiles differ greatly in terms of concentrations and size distributions according to the task performed. The size distributions recorded during tasks were different from both those recorded during periods with no activity and from the background. The airborne concentration profiles of the nanoparticles varied according to not only the type of workplace but also the concentration metrics. The concentrations measured by surface area and the number concentrations measured by condensation particle counter, particulate matter 1.0, and TWA mass concentrations all showed a similar pattern, whereas the number concentrations measured by scanning mobility particle sizer indicated that the welding fume concentrations at one of the welding workplaces were unexpectedly higher than were those at workplaces that were engineering nanoparticles. This study suggests that a task-based exposure assessment can provide useful information regarding the exposure profiles of nanoparticles and can therefore be used as an exposure assessment tool.

  8. Underwater noise modelling for environmental impact assessment

    Energy Technology Data Exchange (ETDEWEB)

    Farcas, Adrian [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom); Thompson, Paul M. [Lighthouse Field Station, Institute of Biological and Environmental Sciences, University of Aberdeen, Cromarty IV11 8YL (United Kingdom); Merchant, Nathan D., E-mail: nathan.merchant@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT (United Kingdom)

    2016-02-15

    Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

  9. Underwater noise modelling for environmental impact assessment

    International Nuclear Information System (INIS)

    Farcas, Adrian; Thompson, Paul M.; Merchant, Nathan D.

    2016-01-01

    Assessment of underwater noise is increasingly required by regulators of development projects in marine and freshwater habitats, and noise pollution can be a constraining factor in the consenting process. Noise levels arising from the proposed activity are modelled and the potential impact on species of interest within the affected area is then evaluated. Although there is considerable uncertainty in the relationship between noise levels and impacts on aquatic species, the science underlying noise modelling is well understood. Nevertheless, many environmental impact assessments (EIAs) do not reflect best practice, and stakeholders and decision makers in the EIA process are often unfamiliar with the concepts and terminology that are integral to interpreting noise exposure predictions. In this paper, we review the process of underwater noise modelling and explore the factors affecting predictions of noise exposure. Finally, we illustrate the consequences of errors and uncertainties in noise modelling, and discuss future research needs to reduce uncertainty in noise assessments.

  10. The Health Impacts of Energy Policy Pathways in Ulaanbaatar, Mongolia: A Total Exposure Assessment

    Science.gov (United States)

    Hill, L. A.; Damdinsuren, Y.; Olkhanud, P. B.; Smith, K. R.; Turner, J. R.; Edwards, R.; Odsuren, M.; Ochir, C.

    2015-12-01

    Ulaanbaatar is home to nearly half of Mongolia's 2.8 million residents. The city's rapid growth, frigid winters, valley topography, and reliance on coal-fired stoves have led to some of the worst winter pollution levels in the world. To better understand this issue, we modeled integrated PM2.5exposures and related health impacts for various city-wide heating policies through 2024. This assessment is one of the first to employ a total exposure approach and results of the 2014 Comparative Risk Assessments of the Global Burden of Disease Project (CRA/GBD) in a policy-relevant energy study. Emissions related to heating, traffic, and power generation were considered under Business as Usual, Moderate Improvement, and Max Improvement scenarios. Calibrated outdoor models were combined with indoor models, local infiltration and time activity estimates, and demographic projections to estimate PM2.5exposures in 2014 and 2024. Indoor exposures were assigned by heating type, home type, and smoking status; outdoor exposures were assigned through geocoding. Population average annual exposures were calculated and applied to local disease rates and integrated exposure-response curves (2014 CRA/GBD) to arrive at annual projections of premature deaths and DALYs. We estimate 2014 annual average exposures at 68 μg/m3, dictated almost exclusively by indoor winter exposures. Under current trends, annual exposures increase 10% to 75 μg/m3 in 2024. This is in stark contrast to the moderate and max improvement scenarios, which lead to 2024 annual exposures that are 31%, and 68% lower, respectively. Under the Moderate scenario, 2024 per capita annual DALY and death burdens drop 26% and 22%, respectively, from 2014 levels. Under the Max scenario, 2024 per capita annual DALY and death burdens drop 71% and 66%, respectively, from 2014. SHS becomes a major contributor as emissions from other sectors decrease. Reductions are dominated by cardiovascular and lower respiratory diseases in children.

  11. Occupational exposure assessment in a radioactive facility: a preliminary evaluation

    International Nuclear Information System (INIS)

    Alves, Alice dos Santos; Gerulis, Eduardo; Sanches, Matias P.; Carneiro, Janete C.G.G.

    2013-01-01

    The risk that a worker has found on the job is a function of the hazards present and his exposure level to those hazards. Exposure and risk assessment is therefore the heart of all occupational health and industrial hygiene programs involving a continuous process of information gathering. The use of a systematic method to characterize workplace exposures to chemical, physical and biological risks is a fundamental part of this process. This study aims to carry out a preliminary evaluation in a radioactive facility, identifying potential exposures and consequently the existing occupational hazards (risk/agent) in the workplace which the employee is subject. The study is based on proposal to carry out a basic characterization of the facility, which could be the first step in the investigation of occupational exposure. For this study was essential to know the workplace, potential risks and agents; workforce profile including assignment of tasks, sources of exposure processes, and control measures. The main tool used in this study was based on references, records, standards, procedures, interviews with the workers and with management. Since the basic characterization of the facility has been carried out, consequently the potential exposure to the agents of risks to workers has been identified. The study provided an overview of the perception of risk founded at facility studied. It is expected to contribute with the occupational health program resources for welfare of the worker. (author)

  12. Occupational exposure assessment in a radioactive facility: a preliminary evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Alice dos Santos; Gerulis, Eduardo; Sanches, Matias P.; Carneiro, Janete C.G.G., E-mail: alicesante@hotmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    The risk that a worker has found on the job is a function of the hazards present and his exposure level to those hazards. Exposure and risk assessment is therefore the heart of all occupational health and industrial hygiene programs involving a continuous process of information gathering. The use of a systematic method to characterize workplace exposures to chemical, physical and biological risks is a fundamental part of this process. This study aims to carry out a preliminary evaluation in a radioactive facility, identifying potential exposures and consequently the existing occupational hazards (risk/agent) in the workplace which the employee is subject. The study is based on proposal to carry out a basic characterization of the facility, which could be the first step in the investigation of occupational exposure. For this study was essential to know the workplace, potential risks and agents; workforce profile including assignment of tasks, sources of exposure processes, and control measures. The main tool used in this study was based on references, records, standards, procedures, interviews with the workers and with management. Since the basic characterization of the facility has been carried out, consequently the potential exposure to the agents of risks to workers has been identified. The study provided an overview of the perception of risk founded at facility studied. It is expected to contribute with the occupational health program resources for welfare of the worker. (author)

  13. The Potential Neurotoxic Effects of Low-Dose Sarin Exposure in a Guinea Pig Model

    Science.gov (United States)

    2002-01-01

    1 THE POTENTIAL NEUROTOXIC EFFECTS OF LOW-DOSE SARIN EXPOSURE IN A GUINEA PIG MODEL Melinda R. Roberson, PhD, Michelle B. Schmidt...Proving Ground, MD 21010 USA ABSTRACT This study is assessing the effects in guinea pigs of repeated low-dose exposure to the nerve...COVERED - 4. TITLE AND SUBTITLE The Potential Neurotoxic Effects Of Low-Dose Sarin Exposure In A Guinea Pig Model 5a. CONTRACT NUMBER 5b

  14. Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Monthly progress reports and final report, October--December 1994

    International Nuclear Information System (INIS)

    Hoffman, F.O.

    1995-01-01

    The objective of Task 7.lD was to (1) establish a collaborative US-USSR effort to improve and validate our methods of forecasting doses and dose commitments from the direct contamination of food sources, and (2) perform experiments and validation studies to improve our ability to predict rapidly and accurately the long-term internal dose from the contamination of agricultural soil. At early times following an accident, the direct contamination of pasture and food stuffs, particularly leafy vegetation and grain, can be of great importance. This situation has been modeled extensively. However, models employed then to predict the deposition, retention and transport of radionuclides in terrestrial environments employed concepts and data bases that were more than a decade old. The extent to which these models have been tested with independent data sets was limited. The data gathered in the former-USSR (and elsewhere throughout the Northern Hemisphere) offered a unique opportunity to test model predictions of wet and dry deposition, agricultural foodchain bioaccumulation, and short- and long-term retention, redistribution, and resuspension of radionuclides from a variety of natural and artificial surfaces. The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates the activity of Task 7.lD into a multinational effort to evaluate models and data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two studies, BIOMOVS (BIOspheric MOdel Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (VAlidation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains

  15. Use of international data sets to evaluate and validate pathway assessment models applicable to exposure and dose reconstruction at DOE facilities. Monthly progress reports and final report, October--December 1994

    Energy Technology Data Exchange (ETDEWEB)

    Hoffman, F.O. [Senes Oak Ridge, Inc., TN (United States). Center for Risk Analysis

    1995-04-01

    The objective of Task 7.lD was to (1) establish a collaborative US-USSR effort to improve and validate our methods of forecasting doses and dose commitments from the direct contamination of food sources, and (2) perform experiments and validation studies to improve our ability to predict rapidly and accurately the long-term internal dose from the contamination of agricultural soil. At early times following an accident, the direct contamination of pasture and food stuffs, particularly leafy vegetation and grain, can be of great importance. This situation has been modeled extensively. However, models employed then to predict the deposition, retention and transport of radionuclides in terrestrial environments employed concepts and data bases that were more than a decade old. The extent to which these models have been tested with independent data sets was limited. The data gathered in the former-USSR (and elsewhere throughout the Northern Hemisphere) offered a unique opportunity to test model predictions of wet and dry deposition, agricultural foodchain bioaccumulation, and short- and long-term retention, redistribution, and resuspension of radionuclides from a variety of natural and artificial surfaces. The current objective of this project is to evaluate and validate pathway-assessment models applicable to exposure and dose reconstruction at DOE facilities through use of international data sets. This project incorporates the activity of Task 7.lD into a multinational effort to evaluate models and data used for the prediction of radionuclide transfer through agricultural and aquatic systems to humans. It also includes participation in two studies, BIOMOVS (BIOspheric MOdel Validation Study) with the Swedish National Institute for Radiation Protection and VAMP (VAlidation of Model Predictions) with the International Atomic Energy Agency, that address testing the performance of models of radionuclide transport through foodchains.

  16. Drone based measurement system for radiofrequency exposure assessment.

    Science.gov (United States)

    Joseph, Wout; Aerts, Sam; Vandenbossche, Matthias; Thielens, Arno; Martens, Luc

    2016-03-10

    For the first time, a method to assess radiofrequency (RF) electromagnetic field (EMF) exposure of the general public in real environments with a true free-space antenna system is presented. Using lightweight electronics and multiple antennas placed on a drone, it is possible to perform exposure measurements. This technique will enable researchers to measure three-dimensional RF-EMF exposure patterns accurately in the future and at locations currently difficult to access. A measurement procedure and appropriate measurement settings have been developed. As an application, outdoor measurements are performed as a function of height up to 60 m for Global System for Mobile Communications (GSM) 900 MHz base station exposure. Bioelectromagnetics. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

  17. Comparison of occupational exposure assessment tools and concepts for nanomaterials

    DEFF Research Database (Denmark)

    Liguori, Biase; Hansen, Steffen Foss; Baun, Anders

    The development, production and application of engineered nanomaterials have been growing in different fields. This leads to a consequent increased potential of exposure to nanomaterials in the working environment. However to determine the potential exposure risk is a challenging task for risk...... for Nanomaterials”; “NanoSafer vs. 1.1 – A web-based precautionary risk assessment tool for manufactured nanomaterials using first order modeling” Based on the literature information we have analyzed these tools and discussed elements regarding: the domain of application and whether it accounts for the nanospecific...... factor or nano-relevance; the work exposure scenario, for which types of processes they may be used; are the tools using the source-transmission-receptor approach; the input data requirements; whether the tools included qualitative or semi-quantitative or quantitative evaluations of the exposure; whether...

  18. Integrated Assessment Model Evaluation

    Science.gov (United States)

    Smith, S. J.; Clarke, L.; Edmonds, J. A.; Weyant, J. P.

    2012-12-01

    Integrated assessment models of climate change (IAMs) are widely used to provide insights into the dynamics of the coupled human and socio-economic system, including emission mitigation analysis and the generation of future emission scenarios. Similar to the climate modeling community, the integrated assessment community has a two decade history of model inter-comparison, which has served as one of the primary venues for model evaluation and confirmation. While analysis of historical trends in the socio-economic system has long played a key role in diagnostics of future scenarios from IAMs, formal hindcast experiments are just now being contemplated as evaluation exercises. Some initial thoughts on setting up such IAM evaluation experiments are discussed. Socio-economic systems do not follow strict physical laws, which means that evaluation needs to take place in a context, unlike that of physical system models, in which there are few fixed, unchanging relationships. Of course strict validation of even earth system models is not possible (Oreskes etal 2004), a fact borne out by the inability of models to constrain the climate sensitivity. Energy-system models have also been grappling with some of the same questions over the last quarter century. For example, one of "the many questions in the energy field that are waiting for answers in the next 20 years" identified by Hans Landsberg in 1985 was "Will the price of oil resume its upward movement?" Of course we are still asking this question today. While, arguably, even fewer constraints apply to socio-economic systems, numerous historical trends and patterns have been identified, although often only in broad terms, that are used to guide the development of model components, parameter ranges, and scenario assumptions. IAM evaluation exercises are expected to provide useful information for interpreting model results and improving model behavior. A key step is the recognition of model boundaries, that is, what is inside

  19. Migration modeling to estimate exposure to chemicals in food packaging for application in highthroughput risk-based screening and Life Cycle Assessment

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Jolliet, O.; Huang, L.

    2017-01-01

    concentration in food for diverse scenarios. Therefore a partition coefficient model, as a function of a chemical’s octanol-water partition coefficient and a food’s ethanol-equivalency, was also developed. When using measured diffusion coefficients the model accurately predicted (R2 = 0.9, SE = 0.5) hundreds...

  20. Road traffic air and noise pollution exposure assessment - A review of tools and techniques.

    Science.gov (United States)

    Khan, Jibran; Ketzel, Matthias; Kakosimos, Konstantinos; Sørensen, Mette; Jensen, Steen Solvang

    2018-09-01

    Road traffic induces air and noise pollution in urban environments having negative impacts on human health. Thus, estimating exposure to road traffic air and noise pollution (hereafter, air and noise pollution) is important in order to improve the understanding of human health outcomes in epidemiological studies. The aims of this review are (i) to summarize current practices of modelling and exposure assessment techniques for road traffic air and noise pollution (ii) to highlight the potential of existing tools and techniques for their combined exposure assessment for air and noise together with associated challenges, research gaps and priorities. The study reviews literature about air and noise pollution from urban road traffic, including other relevant characteristics such as the employed dispersion models, Geographic Information System (GIS)-based tool, spatial scale of exposure assessment, study location, sample size, type of traffic data and building geometry information. Deterministic modelling is the most frequently used assessment technique for both air and noise pollution of short-term and long-term exposure. We observed a larger variety among air pollution models as compared to the applied noise models. Correlations between air and noise pollution vary significantly (0.05-0.74) and are affected by several parameters such as traffic attributes, building attributes and meteorology etc. Buildings act as screens for the dispersion of pollution, but the reduction effect is much larger for noise than for air pollution. While, meteorology has a greater influence on air pollution levels as compared to noise, although also important for noise pollution. There is a significant potential for developing a standard tool to assess combined exposure of traffic related air and noise pollution to facilitate health related studies. GIS, due to its geographic nature, is well established and has a significant capability to simultaneously address both exposures. Copyright

  1. Korean Ministry of Environment's web-based visual consumer product exposure and risk assessment system (COPER).

    Science.gov (United States)

    Lee, Hunjoo; Lee, Kiyoung; Park, Ji Young; Min, Sung-Gi

    2017-05-01

    With support from the Korean Ministry of the Environment (ME), our interdisciplinary research staff developed the COnsumer Product Exposure and Risk assessment system (COPER). This system includes various databases and features that enable the calculation of exposure and determination of risk caused by consumer products use. COPER is divided into three tiers: the integrated database layer (IDL), the domain specific service layer (DSSL), and the exposure and risk assessment layer (ERAL). IDL is organized by the form of the raw data (mostly non-aggregated data) and includes four sub-databases: a toxicity profile, an inventory of Korean consumer products, the weight fractions of chemical substances in the consumer products determined by chemical analysis and national representative exposure factors. DSSL provides web-based information services corresponding to each database within IDL. Finally, ERAL enables risk assessors to perform various exposure and risk assessments, including exposure scenario design via either inhalation or dermal contact by using or organizing each database in an intuitive manner. This paper outlines the overall architecture of the system and highlights some of the unique features of COPER based on visual and dynamic rendering engine for exposure assessment model on web.

  2. Variability and uncertainty in Swedish exposure factors for use in quantitative exposure assessments.

    Science.gov (United States)

    Filipsson, Monika; Öberg, Tomas; Bergbäck, Bo

    2011-01-01

    Information of exposure factors used in quantitative risk assessments has previously been compiled and reported for U.S. and European populations. However, due to the advancement of science and knowledge, these reports are in continuous need of updating with new data. Equally important is the change over time of many exposure factors related to both physiological characteristics and human behavior. Body weight, skin surface, time use, and dietary habits are some of the most obvious examples covered here. A wealth of data is available from literature not primarily gathered for the purpose of risk assessment. Here we review a number of key exposure factors and compare these factors between northern Europe--here represented by Sweden--and the United States. Many previous compilations of exposure factor data focus on interindividual variability and variability between sexes and age groups, while uncertainty is mainly dealt with in a qualitative way. In this article variability is assessed along with uncertainty. As estimates of central tendency and interindividual variability, mean, standard deviation, skewness, kurtosis, and multiple percentiles were calculated, while uncertainty was characterized using 95% confidence intervals for these parameters. The presented statistics are appropriate for use in deterministic analyses using point estimates for each input parameter as well as in probabilistic assessments. © 2010 Society for Risk Analysis.

  3. PRELIMINARY EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY

    Science.gov (United States)

    The Tampa Asthmatic Children's Study (TACS) was a pilot study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools. The four-week study was performed in October and November, 2003. The study involved repeated daily...

  4. EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY (TACS)

    Science.gov (United States)

    The Tampa Asthmatic Children's Study (TACS) was a pilot study that focused on developing and evaluating air pollution exposure assessment methods and participant recruiting tools. The four-week study was performed in October and November, 2003. The study involved repeated daily...

  5. Biocides Steering Group on human exposure assessment: A preliminary report

    NARCIS (Netherlands)

    Hemmen, J.J. van

    1999-01-01

    In a project granted by DG XI of the European Commission, it is attempted to collate experimental and theoretical data on human (workers and consumers) exposure assessment to biocidal products, and to outline the methodology for sampling and measurement. On the basis of the available evidence,

  6. Research and application of quantitative assessment model on chemical substances dermal exposure%化学物质经皮职业暴露定量评估模型的研究及应用

    Institute of Scientific and Technical Information of China (English)

    陈会祥; 黄德寅; 王卉; 薄亚莉; 孙倩; 张倩; 李敏嫣

    2017-01-01

    目的 验证NIOSH定量评估模型模拟结果的可靠性和准确性,并通过实例应用,评估有毒化学物质皮肤接触的吸收程度,提出相应的防护措施建议.方法 选择几种典型的易经皮吸收的化学物质,通过欧洲有毒化学物质皮肤吸收的评估和预测数据库(EDETOX Database)获取其经皮吸收实验数据,将这些研究实例通过NIOSH模型进行吸收率的模拟,将模拟结果与实验数据对比并进行统计学分析,评价NIOSH模型的可靠性和准确性.再以三甲苯磷酸酯和苯酚为实例,采用NIOSH模型评估吸收的剂量(mg),将我国的职业接触浓度限值(mg/m3)转换为接触当量限值(mg),对经由皮肤吸收的职业暴露程度进行判定.结果 模型模拟结果和实验数据的差别无统计学意义(P>0.05).实例应用模拟结果显示,三甲苯磷酸酯3种模拟场景的8h、150 h吸收剂量分别为0.01 mg、0.03 mg、0.03 mg和0.76 mg、4.48 mg、6.93 mg,未超过时间折算接触限值当量(0.67 mg、12.56 mg);苯酚3种模拟场景的8h吸收剂量分别为7.10mg、2.35 mg、15.40 mg,亦未超过时间折算接触限值当量(22.46 mg).结论 该模型具有一定的准确性和可靠性.实例应用显示,NIOSH模型对于经皮吸收的影响因素考虑全面,职业暴露场景的设置灵活方便,对于工作场所化学物质经皮吸收职业暴露评估具有较强的实用性.%Objective To verify the reliability and accuracy of NIOSH quantitative assessment model and evaluate the dermal absorption degree of chemical substances by skin exposure by practice application examples,thereby offer corresponding protection proposals.Methods Several typical chemical substances that easy to be absorpted through skin were selected,the experiment data of skin absorption was obtained from EDETOX Database;compare the skin absorption simulation results by NIOSH quantitative as sessment model with the data from EDETOX Database and take statistical analysis

  7. Environmental exposure assessment in European birth cohorts: results from the ENRIECO project

    Directory of Open Access Journals (Sweden)

    Gehring Ulrike

    2013-01-01

    Full Text Available Abstract Environmental exposures during pregnancy and early life may have adverse health effects. Single birth cohort studies often lack statistical power to tease out such effects reliably. To improve the use of existing data and to facilitate collaboration among these studies, an inventory of the environmental exposure and health data in these studies was made as part of the ENRIECO (Environmental Health Risks in European Birth Cohorts project. The focus with regard to exposure was on outdoor air pollution, water contamination, allergens and biological organisms, metals, pesticides, smoking and second hand tobacco smoke (SHS, persistent organic pollutants (POPs, noise, radiation, and occupational exposures. The review lists methods and data on environmental exposures in 37 European birth cohort studies. Most data is currently available for smoking and SHS (N=37 cohorts, occupational exposures (N=33, outdoor air pollution, and allergens and microbial agents (N=27. Exposure modeling is increasingly used for long-term air pollution exposure assessment; biomonitoring is used for assessment of exposure to metals, POPs and other chemicals; and environmental monitoring for house dust mite exposure assessment. Collaborative analyses with data from several birth cohorts have already been performed successfully for outdoor air pollution, water contamination, allergens, biological contaminants, molds, POPs and SHS. Key success factors for collaborative analyses are common definitions of main exposure and health variables. Our review emphasizes that such common definitions need ideally be arrived at in the study design phase. However, careful comparison of methods used in existing studies also offers excellent opportunities for collaborative analyses. Investigators can use this review to evaluate the potential for future collaborative analyses with respect to data availability and methods used in the different cohorts and to identify potential partners

  8. Truncated Levy flights and agenda-based mobility are useful for the assessment of personal human exposure

    International Nuclear Information System (INIS)

    Schlink, Uwe; Ragas, Ad M.J.

    2011-01-01

    Receptor-oriented approaches can assess the individual-specific exposure to air pollution. In such an individual-based model we analyse the impact of human mobility to the personal exposure that is perceived by individuals simulated in an exemplified urban area. The mobility models comprise random walk (reference point mobility, RPM), truncated Levy flights (TLF), and agenda-based walk (RPMA). We describe and review the general concepts and provide an inter-comparison of these concepts. Stationary and ergodic behaviour are explained and applied as well as performance criteria for a comparative evaluation of the investigated algorithms. We find that none of the studied algorithm results in purely random trajectories. TLF and RPMA prove to be suitable for human mobility modelling, because they provide conditions for very individual-specific trajectories and exposure. Suggesting these models we demonstrate the plausibility of their results for exposure to air-borne benzene and the combined exposure to benzene and nonane. - Highlights: → Human exposure to air pollutants is influenced by a person's movement in the urban area. → We provide a simulation study of approaches to modelling personal exposure. → Agenda-based models and truncated Levy flights are recommended for exposure assessment. → The procedure is demonstrated for benzene exposure in an urban region. - Truncated Levy flights and agenda-based mobility are useful for the assessment of personal human exposure.

  9. Comparative Probabilistic Assessment of Occupational Pesticide Exposures Based on Regulatory Assessments

    Science.gov (United States)

    Pouzou, Jane G.; Cullen, Alison C.; Yost, Michael G.; Kissel, John C.; Fenske, Richard A.

    2018-01-01

    Implementation of probabilistic analyses in exposure assessment can provide valuable insight into the risks of those at the extremes of population distributions, including more vulnerable or sensitive subgroups. Incorporation of these analyses into current regulatory methods for occupational pesticide exposure is enabled by the exposure data sets and associated data currently used in the risk assessment approach of the Environmental Protection Agency (EPA). Monte Carlo simulations were performed on exposure measurements from the Agricultural Handler Exposure Database and the Pesticide Handler Exposure Database along with data from the Exposure Factors Handbook and other sources to calculate exposure rates for three different neurotoxic compounds (azinphos methyl, acetamiprid, emamectin benzoate) across four pesticide-handling scenarios. Probabilistic estimates of doses were compared with the no observable effect levels used in the EPA occupational risk assessments. Some percentage of workers were predicted to exceed the level of concern for all three compounds: 54% for azinphos methyl, 5% for acetamiprid, and 20% for emamectin benzoate. This finding has implications for pesticide risk assessment and offers an alternative procedure that may be more protective of those at the extremes of exposure than the current approach. PMID:29105804

  10. Comparative Probabilistic Assessment of Occupational Pesticide Exposures Based on Regulatory Assessments.

    Science.gov (United States)

    Pouzou, Jane G; Cullen, Alison C; Yost, Michael G; Kissel, John C; Fenske, Richard A

    2017-11-06

    Implementation of probabilistic analyses in exposure assessment can provide valuable insight into the risks of those at the extremes of population distributions, including more vulnerable or sensitive subgroups. Incorporation of these analyses into current regulatory methods for occupational pesticide exposure is enabled by the exposure data sets and associated data currently used in the risk assessment approach of the Environmental Protection Agency (EPA). Monte Carlo simulations were performed on exposure measurements from the Agricultural Handler Exposure Database and the Pesticide Handler Exposure Database along with data from the Exposure Factors Handbook and other sources to calculate exposure rates for three different neurotoxic compounds (azinphos methyl, acetamiprid, emamectin benzoate) across four pesticide-handling scenarios. Probabilistic estimates of doses were compared with the no observable effect levels used in the EPA occupational risk assessments. Some percentage of workers were predicted to exceed the level of concern for all three compounds: 54% for azinphos methyl, 5% for acetamiprid, and 20% for emamectin benzoate. This finding has implications for pesticide risk assessment and offers an alternative procedure that may be more protective of those at the extremes of exposure than the current approach. © 2017 Society for Risk Analysis.

  11. Development of a method for personal, spatiotemporal exposure assessment.

    Science.gov (United States)

    Adams, Colby; Riggs, Philip; Volckens, John

    2009-07-01

    This work describes the development and evaluation of a high resolution, space and time-referenced sampling method for personal exposure assessment to airborne particulate matter (PM). This method integrates continuous measures of personal PM levels with the corresponding location-activity (i.e. work/school, home, transit) of the subject. Monitoring equipment include a small, portable global positioning system (GPS) receiver, a miniature aerosol nephelometer, and an ambient temperature monitor to estimate the location, time, and magnitude of personal exposure to particulate matter air pollution. Precision and accuracy of each component, as well as the integrated method performance were tested in a combination of laboratory and field tests. Spatial data was apportioned into pre-determined location-activity categories (i.e. work/school, home, transit) with a simple, temporospatially-based algorithm. The apportioning algorithm was extremely effective with an overall accuracy of 99.6%. This method allows examination of an individual's estimated exposure through space and time, which may provide new insights into exposure-activity relationships not possible with traditional exposure assessment techniques (i.e., time-integrated, filter-based measurements). Furthermore, the method is applicable to any contaminant or stressor that can be measured on an individual with a direct-reading sensor.

  12. Environmental exposure assessment framework for nanoparticles in solid waste

    Science.gov (United States)

    Boldrin, Alessio; Hansen, Steffen Foss; Baun, Anders; Hartmann, Nanna Isabella Bloch; Astrup, Thomas Fruergaard

    2014-06-01

    Information related to the potential environmental exposure of engineered nanomaterials (ENMs) in the solid waste management phase is extremely scarce. In this paper, we define nanowaste as separately collected or collectable waste materials which are or contain ENMs, and we present a five-step framework for the systematic assessment of ENM exposure during nanowaste management. The framework includes deriving EOL nanoproducts and evaluating the physicochemical properties of the nanostructure, matrix properties and nanowaste treatment processes as well as transformation processes and environment releases, eventually leading to a final assessment of potential ENM exposure. The proposed framework was applied to three selected nanoproducts: nanosilver polyester textile, nanoTiO2 sunscreen lotion and carbon nanotube tennis racquets. We found that the potential global environmental exposure of ENMs associated with these three products was an estimated 0.5-143 Mg/year, which can also be characterised qualitatively as medium, medium, low, respectively. Specific challenges remain and should be subject to further research: (1) analytical techniques for the characterisation of nanowaste and its transformation during waste treatment processes, (2) mechanisms for the release of ENMs, (3) the quantification of nanowaste amounts at the regional scale, (4) a definition of acceptable limit values for exposure to ENMs from nanowaste and (5) the reporting of nanowaste generation data.

  13. Performance of GPS-devices for environmental exposure assessment.

    Science.gov (United States)

    Beekhuizen, Johan; Kromhout, Hans; Huss, Anke; Vermeulen, Roel

    2013-01-01

    Integration of individual time-location patterns with spatially resolved exposure maps enables a more accurate estimation of personal exposures to environmental pollutants than using estimates at fixed locations. Current global positioning system (GPS) devices can be used to track an individual's location. However, information on GPS-performance in environmental exposure assessment is largely missing. We therefore performed two studies. First, a commute-study, where the commute of 12 individuals was tracked twice, testing GPS-performance for five transport modes and two wearing modes. Second, an urban-tracking study, where one individual was tracked repeatedly through different areas, focused on the effect of building obstruction on GPS-performance. The median error from the true path for walking was 3.7 m, biking 2.9 m, train 4.8 m, bus 4.9 m, and car 3.3 m. Errors were larger in a high-rise commercial area (median error=7.1 m) compared with a low-rise residential area (median error=2.2 m). Thus, GPS-performance largely depends on the transport mode and urban built-up. Although ~85% of all errors were 50 m. Modern GPS-devices are useful tools for environmental exposure assessment, but large GPS-errors might affect estimates of exposures with high spatial variability.

  14. Inhalation Exposure Input Parameters for the Biosphere Model

    Energy Technology Data Exchange (ETDEWEB)

    M. Wasiolek

    2006-06-05

    This analysis is one of the technical reports that support the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), referred to in this report as the biosphere model. ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the conceptual model as well as the mathematical model and its input parameters. This report documents development of input parameters for the biosphere model that are related to atmospheric mass loading and supports the use of the model to develop biosphere dose conversion factors (BDCFs). The biosphere model is one of a series of process models supporting the total system performance assessment (TSPA) for a Yucca Mountain repository. ''Inhalation Exposure Input Parameters for the Biosphere Model'' is one of five reports that develop input parameters for the biosphere model. A graphical representation of the documentation hierarchy for the biosphere model is presented in Figure 1-1 (based on BSC 2006 [DIRS 176938]). This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and how this analysis report contributes to biosphere modeling. This analysis report defines and justifies values of atmospheric mass loading for the biosphere model. Mass loading is the total mass concentration of resuspended particles (e.g., dust, ash) in a volume of air. Mass loading values are used in the air submodel of the biosphere model to calculate concentrations of radionuclides in air inhaled by a receptor and concentrations in air surrounding crops. Concentrations in air to which the receptor is exposed are then used in the inhalation submodel to calculate the dose contribution to the receptor from inhalation of contaminated airborne particles. Concentrations in air surrounding plants are used in the plant submodel to calculate the concentrations of radionuclides in foodstuffs contributed from uptake by foliar interception. This

  15. Inhalation Exposure Input Parameters for the Biosphere Model

    International Nuclear Information System (INIS)

    M. Wasiolek

    2006-01-01

    This analysis is one of the technical reports that support the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN), referred to in this report as the biosphere model. ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the conceptual model as well as the mathematical model and its input parameters. This report documents development of input parameters for the biosphere model that are related to atmospheric mass loading and supports the use of the model to develop biosphere dose conversion factors (BDCFs). The biosphere model is one of a series of process models supporting the total system performance assessment (TSPA) for a Yucca Mountain repository. ''Inhalation Exposure Input Parameters for the Biosphere Model'' is one of five reports that develop input parameters for the biosphere model. A graphical representation of the documentation hierarchy for the biosphere model is presented in Figure 1-1 (based on BSC 2006 [DIRS 176938]). This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling and how this analysis report contributes to biosphere modeling. This analysis report defines and justifies values of atmospheric mass loading for the biosphere model. Mass loading is the total mass concentration of resuspended particles (e.g., dust, ash) in a volume of air. Mass loading values are used in the air submodel of the biosphere model to calculate concentrations of radionuclides in air inhaled by a receptor and concentrations in air surrounding crops. Concentrations in air to which the receptor is exposed are then used in the inhalation submodel to calculate the dose contribution to the receptor from inhalation of contaminated airborne particles. Concentrations in air surrounding plants are used in the plant submodel to calculate the concentrations of radionuclides in foodstuffs contributed from uptake by foliar interception. This report is concerned primarily with the

  16. Dose assessment models. Annex A

    International Nuclear Information System (INIS)

    1982-01-01

    The models presented in this chapter have been separated into 2 general categories: environmental transport models which describe the movement of radioactive materials through all sectors of the environment after their release, and dosimetric models to calculate the absorbed dose following an intake of radioactive materials or exposure to external irradiation. Various sections of this chapter also deal with atmospheric transport models, terrestrial models, and aquatic models.

  17. Experimental Model for Retrospective Assessment of X-Ray Exposures in Dento-Maxillary Radiology Measured by Electron Paramagnetic Resonance in Tooth Enamel

    Directory of Open Access Journals (Sweden)

    Ioana Costina DÂNŞOREANU

    2009-12-01

    Full Text Available Electron paramagnetic resonance (EPR dosimetry of human tooth enamel has been widely used in measuring radiation doses in various scenarios. For experimental purposes in X-ray diagnostic or therapy human persons can not be involved. For such cases we have developed an EPR dosimetry technique making use of enamel of molars extracted from pigs. The method can evaluate doses and dose-profiles of irradiated teeth at low level as 50 – 100 mGy (in air. EPR-spectra acquisition, data processing and dose assessment were done using non-dedicated equipment, devices and software.

  18. Nano-metal oxides: Exposure and engineering control assessment.

    Science.gov (United States)

    Garcia, Alberto; Eastlake, Adrienne; Topmiller, Jennifer L; Sparks, Christopher; Martinez, Kenneth; Geraci, Charles L

    2017-09-01

    In January 2007, the National Institute for Occupational Safety and Health (NIOSH) conducted a field study to evaluate process specific emissions during the production of ENMs. This study was performed using the nanoparticle emission assessment technique (NEAT). During this study, it was determined that ENMs were released during production and cleaning of the process reactor. Airborne concentrations of silver, nickel, and iron were found both in the employee's personal breathing zone and area samples during reactor cleaning. At the completion of this initial survey, it was suggested that a flanged attachment be added to the local exhaust ventilation system.  NIOSH re-evaluated the facility in December 2011 to assess worker exposures following an increase in production rates. This study included a fully comprehensive emissions, exposure, and engineering control evaluation of the entire process. This study made use of the nanoparticle exposure assessment technique (NEAT 2.0). Data obtained from filter-based samples and direct reading instruments indicate that reactor cleanout increased the overall particle concentration in the immediate area. However, it does not appear that these concentrations affect areas outside of the production floor. As the distance between the reactor and the sample location increased, the observed particle number concentration decreased, creating a concentration gradient with respect to the reactor. The results of this study confirm that the flanged attachment on the local exhaust ventilation system served to decrease exposure potential.  Given the available toxicological data of the metals evaluated, caution is warranted. One should always keep in mind that occupational exposure levels were not developed specifically for nanoscale particles. With data suggesting that certain nanoparticles may be more toxic than the larger counterparts of the same material; employers should attempt to control emissions of these particles at the source

  19. Modeling Exposure to Heat Stress with a Simple Urban Model

    Directory of Open Access Journals (Sweden)

    Peter Hoffmann

    2018-01-01

    Full Text Available As a first step in modeling health-related urban well-being (UrbWellth, a mathematical model is constructed that dynamically simulates heat stress exposure of commuters in an idealized city. This is done by coupling the Simple Urban Radiation Model (SURM, which computes the mean radiant temperature ( T m r t , with a newly developed multi-class multi-mode traffic model. Simulation results with parameters chosen for the city of Hamburg for a hot summer day show that commuters are potentially most exposed to heat stress in the early afternoon when T m r t has its maximum. Varying the morphology with respect to street width and building height shows that a more compact city configuration reduces T m r t and therefore the exposure to heat stress. The impact resulting from changes in the city structure on traffic is simulated to determine the time spent outside during the commute. While the time in traffic jams increases for compact cities, the total commuting time decreases due to shorter distances between home and work place. Concerning adaptation measures, it is shown that increases in the albedo of the urban surfaces lead to an increase in daytime heat stress. Dramatic increases in heat stress exposure are found when both, wall and street albedo, are increased.

  20. Bioaccessibility, dietary exposure and human risk assessment of heavy metals from market vegetables in Hong Kong revealed with an in vitro gastrointestinal model.

    Science.gov (United States)

    Hu, Junli; Wu, Fuyong; Wu, Shengchun; Cao, Zhihong; Lin, Xiangui; Wong, Ming Hung

    2013-04-01

    A systematic survey of heavy metal (HM) concentrations and bioaccessibilities in market vegetables in Hong Kong were carried out for assessing potential health risk to local inhabitants. The average concentrations of Cd, Pb, Cr, Ni, Cu, and Zn in nine major groups of fresh vegetable varied within 0.007-0.053, 0.05-0.17, 0.05-0.24, 0.26-1.1, 0.62-3.0, and 0.96-4.3 mg kg(-1), respectively, and their average bioaccessibilities varied within 21-96%, 20-68%, 24-62%, 29-64%, 30-77%, and 69-94%, respectively. The bioaccessible estimated daily intakes (BEDIs) of Cd, Pb, Cr, Ni, Cu, and Zn from vegetables were far below the tolerable limits. The total bioaccessible target hazard quotient (TBTHQ) of the six HMs was 0.18 and 0.64 for average and high consumers, respectively, with Cd and leafy vegetable being the major risk contributors. Risk assessment of HMs from foods should be modified by taking bioaccessibility into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

  1. Exposure assessment strategies for non-routine work operations (NORWO)

    International Nuclear Information System (INIS)

    Lew, V.; Johnson, J.; Chiusano, S.; McLouth, L.

    1993-01-01

    This meeting is the second in a series of a cooperative effort between the Industrial Hygiene Division of the Office of Health (EH-40) and the Office of Oversight (EM-23) to gain input for the development of a section on NORWO exposure assessment in the Exposure Assessment Strategies and HAZWOPER technical guidance manuals. The first day of the meeting was dedicated to a seminar relating to AIHA Strategy for Occupational Exposure Assessment to NORWO situations. Jeff Miller and Tom Weeda of Radian were the course instructors. The course covered how the elements of basic characterization, prioritization, monitoring and decision making could apply to NORWO situations. Several examples of applications of statistical analysis for decision making were illustrated. In addition, the seminar brought forth some points that need additional examination before the strategy can be applied to NORWO. They are: should qualitative and semi-quantitative data be applied to statistical decision making; should professional judgment be balanced with an acceptable degree of statistical certainty; and the need for development of a standardized application of statistics for the DOE Health ampersand Safety community. The remaining two days of the meeting were devoted to the continued development of guidelines to measure and document, in a technically correct and consistent manner, the exposures DOE environmental restoration and waste management (ERWM) workers receive during NORWO and reflects the perspectives and experiences of the attendees. Formal presentations were given by representatives from Hanford and INEL

  2. Occupational exposure assessment: Practices in Malaysian nuclear agency

    Science.gov (United States)

    Sarowi, S. Muhd; Ramli, S. A.; Kontol, K. Mohamad; Rahman, N. A. H. Abd.

    2016-01-01

    Malaysian Nuclear Agency (Nuclear Malaysia) is the leading agency in introducing and promoting the application of nuclear science technology in Malaysia. The agency provides major nuclear facilities purposely for research and commercialisation such as reactor, irradiation plants and radioisotope production laboratory. When dealing with ionizing radiation, there is an obligatory requirement to monitor and assess the radiation exposure to the workers. The personal dose of radiation workers were monitored monthly by assessing their Thermoluminescence Dosimeter (TLD) dose reading. This paper will discuss the current practice in managing, assessing, record keeping and reporting of the occupational exposure in Nuclear Malaysia including the Health Physic Group roles and challenges. The statistics on occupational radiation exposure of monitored workers working in different fields in Nuclear Malaysia from 2011 - 2013 will also be presented. The results show that the null hypothesis (H₀) was accepted which the means of every populations are all equal or not differ significantly. This hypothesis states that the dose exposure received by the radiation workers in Nuclear Malaysia is similar and there were no significant changes from 2011 to 2013. The radiation monitoring programme correlate with the requirement of our national law, the Atomic Energy Licensing Act 1984 (Act 304).

  3. Occupational exposure assessment: Practices in Malaysian nuclear agency

    Energy Technology Data Exchange (ETDEWEB)

    Sarowi, S. Muhd, E-mail: suzie@nuclearmalaysia.gov.my; Ramli, S. A.; Kontol, K. Mohamad [Radiation Safety & Health Division, Malaysian Nuclear Agency, 43000 Kajang, Selangor (Malaysia); Rahman, N. A. H. Abd. [Faculty of Science & Mathematics, Sultan Idris of Education Universit, 35900, Tanjong Malim, Perak Darul Ridzuan (Malaysia)

    2016-01-22

    Malaysian Nuclear Agency (Nuclear Malaysia) is the leading agency in introducing and promoting the application of nuclear science technology in Malaysia. The agency provides major nuclear facilities purposely for research and commercialisation such as reactor, irradiation plants and radioisotope production laboratory. When dealing with ionizing radiation, there is an obligatory requirement to monitor and assess the radiation exposure to the workers. The personal dose of radiation workers were monitored monthly by assessing their Thermoluminescence Dosimeter (TLD) dose reading. This paper will discuss the current practice in managing, assessing, record keeping and reporting of the occupational exposure in Nuclear Malaysia including the Health Physic Group roles and challenges. The statistics on occupational radiation exposure of monitored workers working in different fields in Nuclear Malaysia from 2011 - 2013 will also be presented. The results show that the null hypothesis (H{sub 0}) was accepted which the means of every populations are all equal or not differ significantly. This hypothesis states that the dose exposure received by the radiation workers in Nuclear Malaysia is similar and there were no significant changes from 2011 to 2013. The radiation monitoring programme correlate with the requirement of our national law, the Atomic Energy Licensing Act 1984 (Act 304)

  4. Occupational exposure assessment: Practices in Malaysian nuclear agency

    International Nuclear Information System (INIS)

    Sarowi, S. Muhd; Ramli, S. A.; Kontol, K. Mohamad; Rahman, N. A. H. Abd.

    2016-01-01

    Malaysian Nuclear Agency (Nuclear Malaysia) is the leading agency in introducing and promoting the application of nuclear science technology in Malaysia. The agency provides major nuclear facilities purposely for research and commercialisation such as reactor, irradiation plants and radioisotope production laboratory. When dealing with ionizing radiation, there is an obligatory requirement to monitor and assess the radiation exposure to the workers. The personal dose of radiation workers were monitored monthly by assessing their Thermoluminescence Dosimeter (TLD) dose reading. This paper will discuss the current practice in managing, assessing, record keeping and reporting of the occupational exposure in Nuclear Malaysia including the Health Physic Group roles and challenges. The statistics on occupational radiation exposure of monitored workers working in different fields in Nuclear Malaysia from 2011 - 2013 will also be presented. The results show that the null hypothesis (H 0 ) was accepted which the means of every populations are all equal or not differ significantly. This hypothesis states that the dose exposure received by the radiation workers in Nuclear Malaysia is similar and there were no significant changes from 2011 to 2013. The radiation monitoring programme correlate with the requirement of our national law, the Atomic Energy Licensing Act 1984 (Act 304)

  5. Use of an aggregate exposure model to estimate consumer exposure to fragrance ingredients in personal care and cosmetic products.

    Science.gov (United States)

    Safford, B; Api, A M; Barratt, C; Comiskey, D; Daly, E J; Ellis, G; McNamara, C; O'Mahony, C; Robison, S; Smith, B; Thomas, R; Tozer, S

    2015-08-01

    Ensuring the toxicological safety of fragrance ingredients used in personal care and cosmetic products is essential in product development and design, as well as in the regulatory compliance of the products. This requires an accurate estimation of consumer exposure which, in turn, requires an understanding of consumer habits and use of products. Where ingredients are used in multiple product types, it is important to take account of aggregate exposure in consumers using these products. This publication investigates the use of a newly developed probabilistic model, the Creme RIFM model, to estimate aggregate exposure to fragrance ingredients using the example of 2-phenylethanol (PEA). The output shown demonstrates the utility of the model in determining systemic and dermal exposure to fragrances from individual products, and aggregate exposure. The model provides valuable information not only for risk assessment, but also for risk management. It should be noted that data on the concentrations of PEA in products used in this article were obtained from limited sources and not the standard, industry wide surveys typically employed by the fragrance industry and are thus presented here to illustrate the output and utility of the newly developed model. They should not be considered an accurate representation of actual exposure to PEA. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Modelling of aircrew radiation exposure during solar particle events

    Science.gov (United States)

    Al Anid, Hani Khaled

    show a very different response during anisotropic events, leading to variations in aircrew radiation doses that may be significant for dose assessment. To estimate the additional exposure due to solar flares, a model was developed using a Monte-Carlo radiation transport code, MCNPX. The model transports an extrapolated particle spectrum based on satellite measurements through the atmosphere using the MCNPX analysis. This code produces the estimated flux at a specific altitude where radiation dose conversion coefficients are applied to convert the particle flux into effective and ambient dose-equivalent rates. A cut-off rigidity model accounts for the shielding effects of the Earth's magnetic field. Comparisons were made between the model predictions and actual flight measurements taken with various types of instruments used to measure the mixed radiation field during Ground Level Enhancements 60 and 65. An anisotropy analysis that uses neutron monitor responses and the pitch angle distribution of energetic solar particles was used to identify particle anisotropy for a solar event in December 2006. In anticipation of future commercial use, a computer code has been developed to implement the radiation dose assessment model for routine analysis. Keywords: Radiation Dosimetry, Radiation Protection, Space Physics.

  7. Assessment of genetic risk for human exposure to radiation

    International Nuclear Information System (INIS)

    Sevcenko, V.A.; Rubanovic, A.V.

    2002-01-01

    Full text: The methodology of assessing the genetic risk of radiation exposure is based on the concept of 'hitting the target' in development of which N.V. Timofeeff-Ressovsky has played and important role. To predict genetic risk posed by irradiation, the U N Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has worked out direct and indirect methods of assessment, extrapolation, integral and palpitation criteria of risk analysis that together permit calculating the risk from human exposure on the basis of data obtained for mice. Based on the reports of UNSCEAR for the period from 1958 to 2001 the paper presents a retrospective analysis of the use of direct methods and the doubling dose method for quantitative determination of the genetic risk of human exposure expressed as different hereditary diseases. As early as 1962 UNSCEAR estimated the doubling dose (a dose causing as many mutations as those occurring spontaneously during one generation) at 1 Gy for cases of exposure to ionizing radiations with low LET at a low dose rate and this value was confirmed in the next UNSCEAR reports up to now. For cases of acute irradiation the doubling dose was estimated at 0,3-0,4 Gy for the period under review. The paper considers the evolution of the concepts of human natural hereditary variability which is a basis for assessing the risk of exposure by the doubling dose method. The level of human natural genetic variability per 1 000 000 newborns is estimated at 738 000 hereditary diseases including mendelian, chromosomal and multifactorial ones. The greatest difficulties in assessing the doubling dose value were found to occur in the case of multifactorial diseases the pheno typical expression of which depends on mutational events in polygenic systems and on numerous environmental factors. The introduction in calculations of the potential recoverability correction factor (RPCF) made it possible to assess the genetic risk taking into account this class of

  8. The Diesel Exhaust in Miners Study: I. Overview of the Exposure Assessment Process

    Science.gov (United States)

    Stewart, Patricia A.; Coble, Joseph B.; Vermeulen, Roel; Schleiff, Patricia; Blair, Aaron; Lubin, Jay; Attfield, Michael; Silverman, Debra T.

    2010-01-01

    This report provides an overview of the exposure assessment process for an epidemiologic study that investigated mortality, with a special focus on lung cancer, associated with diesel exhaust (DE) exposure among miners. Details of several components are provided in four other reports. A major challenge for this study was the development of quantitative estimates of historical exposures to DE. There is no single standard method for assessing the totality of DE, so respirable elemental carbon (REC), a component of DE, was selected as the primary surrogate in this study. Air monitoring surveys at seven of the eight study mining facilities were conducted between 1998 and 2001 and provided reference personal REC exposure levels and measurements for other agents and DE components in the mining environment. (The eighth facility had closed permanently prior to the surveys.) Exposure estimates were developed for mining facility/department/job/year combinations. A hierarchical grouping strategy was developed for assigning exposure levels to underground jobs [based on job titles, on the amount of time spent in various areas of the underground mine, and on similar carbon monoxide (CO, another DE component) concentrations] and to surface jobs (based on the use of, or proximity to, diesel-powered equipment). Time trends in air concentrations for underground jobs were estimated from mining facility-specific prediction models using diesel equipment horsepower, total air flow rates exhausted from the underground mines, and, because there were no historical REC measurements, historical measurements of CO. Exposures to potentially confounding agents, i.e. respirable dust, silica, radon, asbestos, and non-diesel sources of polycyclic aromatic hydrocarbons, also were assessed. Accuracy and reliability of the estimated REC exposures levels were evaluated by comparison with several smaller datasets and by development of alternative time trend models. During 1998–2001, the average

  9. Benchmarking of computer codes and approaches for modeling exposure scenarios

    International Nuclear Information System (INIS)

    Seitz, R.R.; Rittmann, P.D.; Wood, M.I.; Cook, J.R.

    1994-08-01

    The US Department of Energy Headquarters established a performance assessment task team (PATT) to integrate the activities of DOE sites that are preparing performance assessments for the disposal of newly generated low-level waste. The PATT chartered a subteam with the task of comparing computer codes and exposure scenarios used for dose calculations in performance assessments. This report documents the efforts of the subteam. Computer codes considered in the comparison include GENII, PATHRAE-EPA, MICROSHIELD, and ISOSHLD. Calculations were also conducted using spreadsheets to provide a comparison at the most fundamental level. Calculations and modeling approaches are compared for unit radionuclide concentrations in water and soil for the ingestion, inhalation, and external dose pathways. Over 30 tables comparing inputs and results are provided

  10. Health effects from indoor and outdoor exposure to fine particulate matter in life cycle impact assessment

    DEFF Research Database (Denmark)

    Fantke, Peter; McKone, T.E.; Jolliet, Olivier

    2016-01-01

    Exposure to fine particulate matter (PM2.5) pollution is a major contributor to human disease burden as continuously shown in the Global Burden of Disease study series. Exposures to PM2.5 concentration outdoors and indoors contribute almost equally to this burden. Despite the importance, health...... impacts from exposure to PM2.5 are often excluded from life cycle impact assessment (LCIA) characterization profiles. This is in large part because of the lack of well-vetted harmonized guidance about how to consistently assess the exposures and impacts of indoor and outdoor emissions of PM2.5 and its...... precursors. We present a framework for calculating characterization factors for indoor and outdoor emissions of primary PM2.5 and secondary PM2.5 precursors, and a roadmap for further refining this modelling framework for operational use in LCIA. The framework was developed over the last three years...

  11. Pollution exposure on marine protected areas: A global assessment.

    Science.gov (United States)

    Partelow, Stefan; von Wehrden, Henrik; Horn, Olga

    2015-11-15

    Marine protected areas (MPAs) face many challenges in their aim to effectively conserve marine ecosystems. In this study we analyze the extent of pollution exposure on the global fleet of MPAs. This includes indicators for current and future pollution and the implications for regionally clustered groups of MPAs with similar biophysical characteristics. To cluster MPAs into characteristic signature groups, their bathymetry, baseline biodiversity, distance from shore, mean sea surface temperature and mean sea surface salinity were used. We assess the extent at which each signature group is facing exposure from multiple pollution types. MPA groups experience similar pollution exposure on a regional level. We highlight how the challenges that MPAs face can be addressed through governance at the appropriate scale and design considerations for integrated terrestrial and marine management approaches within regional level networks. Furthermore, we present diagnostic social-ecological indicators for addressing the challenges facing unsuccessful MPAs with practical applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Primary blast survival and injury risk assessment for repeated blast exposures.

    Science.gov (United States)

    Panzer, Matthew B; Bass, Cameron R Dale; Rafaels, Karin A; Shridharani, Jay; Capehart, Bruce P

    2012-02-01

    The widespread use of explosives by modern insurgents and terrorists has increased the potential frequency of blast exposure in soldiers and civilians. This growing threat highlights the importance of understanding and evaluating blast injury risk and the increase of injury risk from exposure to repeated blast effects. Data from more than 3,250 large animal experiments were collected from studies focusing on the effects of blast exposure. The current study uses 2,349 experiments from the data collection for analysis of the primary blast injury and survival risk for both long- and short-duration blasts, including the effects from repeated exposures. A piecewise linear logistic regression was performed on the data to develop survival and injury risk assessment curves. New injury risk assessment curves uniting long- and short-duration blasts were developed for incident and reflected pressure measures and were used to evaluate the risk of injury based on blast over pressure, positive-phase duration, and the number of repeated exposures. The risk assessments were derived for three levels of injury severity: nonauditory, pulmonary, and fatality. The analysis showed a marked initial decrease in injury tolerance with each subsequent blast exposure. This effect decreases with increasing number of blast exposures. The new injury risk functions showed good agreement with the existing experimental data and provided a simplified model for primary blast injury risk. This model can be used to predict blast injury or fatality risk for single exposure and repeated exposure cases and has application in modern combat scenarios or in setting occupational health limits. .Copyright © 2012 by Lippincott Williams & Wilkins

  13. Multi-scale spatial modeling of human exposure from local sources to global intake

    DEFF Research Database (Denmark)

    Wannaz, Cedric; Fantke, Peter; Jolliet, Olivier

    2018-01-01

    Exposure studies, used in human health risk and impact assessments of chemicals are largely performed locally or regionally. It is usually not known how global impacts resulting from exposure to point source emissions compare to local impacts. To address this problem, we introduce Pangea......, an innovative multi-scale, spatial multimedia fate and exposure assessment model. We study local to global population exposure associated with emissions from 126 point sources matching locations of waste-to-energy plants across France. Results for three chemicals with distinct physicochemical properties...... occur within a 100 km radius from the source. This suggests that, by neglecting distant low-level exposure, local assessments might only account for fractions of global cumulative intakes. We also study ~10,000 emission locations covering France more densely to determine per chemical and exposure route...

  14. Variation in calculated human exposure. Comparison of calculations with seven European human exposure models

    NARCIS (Netherlands)

    Swartjes F; ECO

    2003-01-01

    Twenty scenarios, differing with respect to land use, soil type and contaminant, formed the basis for calculating human exposure from soil contaminants with the use of models contributed by seven European countries (one model per country). Here, the human exposures to children and children

  15. Risk assessment of fluoride exposure in drinking water of Tunisia.

    Science.gov (United States)

    Guissouma, Wiem; Hakami, Othman; Al-Rajab, Abdul Jabbar; Tarhouni, Jamila

    2017-06-01

    The presence of fluoride in drinking water is known to reduce dental cavities among consumers, but an excessive intake of this anion might leads to dental and skeletal fluorosis. This study reports a complete survey of the fluoridated tap water taken from 100 water consumption points in Tunisia. The fluoride concentrations in tap water were between 0 and 2.4 mg L -1 . Risk assessment of Fluoride exposure was assessed depending on the age of consumers using a four-step method: hazard identification, toxicity reference values selection (TRVs), daily exposure assessment, and risk characterization. Our findings suggest that approximately 75% of the Tunisian population is at risk for dental decay, 25% have a potential dental fluorosis risk, and 20% might have a skeletal fluorosis risk according to the limits of fluoride in drinking water recommended by WHO. More investigations are recommended to assess the exposure risk of fluoride in other sources of drinking water such as bottled water. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Health Risk Assessment of Inhalation Exposure to Formaldehyde and Benzene in Newly Remodeled Buildings, Beijing

    Science.gov (United States)

    Huang, Lihui; Mo, Jinhan; Sundell, Jan; Fan, Zhihua; Zhang, Yinping

    2013-01-01

    Objective To assess health risks associated with inhalation exposure to formaldehyde and benzene mainly emitted from building and decoration materials in newly remodeled indoor spaces in Beijing. Methods We tested the formaldehyde and benzene concentrations in indoor air of 410 dwellings and 451 offices remodeled within the past year, in which the occupants had health concerns about indoor air quality. To assess non-carcinogenic health risks, we compared the data to the health guidelines in China and USA, respectively. To assess carcinogenic health risks, we first modeled indoor personal exposure to formaldehyde and benzene using the concentration data, and then estimated the associated cancer risks by multiplying the indoor personal exposure by the Inhalation Unit Risk values (IURs) provided by the U.S. EPA Integrated Risk Information System (U.S. EPA IRIS) and the California Office of Environmental Health Hazard Assessment (OEHHA), respectively. Results (1) The indoor formaldehyde concentrations of 85% dwellings and 67% offices were above the acute Reference Exposure Level (REL) recommended by the OEHHA and the concentrations of all tested buildings were above the chronic REL recommended by the OEHHA; (2) The indoor benzene concentrations of 12% dwellings and 32% offices exceeded the reference concentration (RfC) recommended by the U.S. EPA IRIS; (3) The median cancer risks from indoor exposure to formaldehyde and benzene were 1,150 and 106 per million (based on U.S. EPA IRIS IURs), 531 and 394 per million (based on OEHHA IURs). Conclusions In the tested buildings, formaldehyde exposure may pose acute and chronic non-carcinogenic health risks to the occupants, whereas benzene exposure may pose chronic non-carcinogenic risks to the occupants. Exposure to both compounds is associated with significant carcinogenic risks. Improvement in ventilation, establishment of volatile organic compounds (VOCs) emission labeling systems for decorating and refurbishing materials

  17. Modeling exposure to air pollution and cardiovascular mortality: the ESCAPE study

    NARCIS (Netherlands)

    Wang, M.|info:eu-repo/dai/nl/345480279

    2013-01-01

    Exposure assessment is one of the key issues for health effect estimates in environmental epidemiology. Recent interest has increased in exposure modeling incorporating Geographic Information System (GIS) data to capture small-scale spatial variability in air pollution concentrations. Land use

  18. Multi-pathway exposure modelling of chemicals in cosmetics with application to shampoo

    DEFF Research Database (Denmark)

    Ernstoff, Alexi S.; Fantke, Peter; Csiszar, Susan A.

    2016-01-01

    We present a novel multi-pathway, mass balance based, fate and exposure model compatible with life cycle and high-throughput screening assessments of chemicals in cosmetic products. The exposures through product use as well as post-use emissions and environmental media were quantified based...

  19. Multi-pathway exposure modelling of chemicals in cosmetics with application to shampoo

    Science.gov (United States)

    We present a novel multi-pathway, mass balance based, fate and exposure model compatible with life cycle and high-throughput screening assessments of chemicals in cosmetic products. The exposures through product use as well as post-use emissions and environmental media were quant...

  20. Probabilistic integrated risk assessment of human exposure risk to environmental bisphenol A pollution sources.

    Science.gov (United States)

    Fu, Keng-Yen; Cheng, Yi-Hsien; Chio, Chia-Pin; Liao, Chung-Min

    2016-10-01

    Environmental bisphenol A (BPA) exposure has been linked to a variety of adverse health effects such as developmental and reproductive issues. However, establishing a clear association between BPA and the likelihood of human health is complex yet fundamentally uncertain. The purpose of this study was to assess the potential exposure risks from environmental BPA among Chinese population based on five human health outcomes, namely immune response, uterotrophic assay, cardiovascular disease (CVD), diabetes, and behavior change. We addressed these health concerns by using a stochastic integrated risk assessment approach. The BPA dose-dependent likelihood of effects was reconstructed by a series of Hill models based on animal models or epidemiological data. We developed a physiologically based pharmacokinetic (PBPK) model that allows estimation of urinary BPA concentration from external exposures. Here we showed that the daily average exposure concentrations of BPA and urinary BPA estimates were consistent with the published data. We found that BPA exposures were less likely to pose significant risks for infants (0-1 year) and adults (male and female >20 years) with human long-term BPA susceptibility in relation to multiple exposure pathways, and for informing the public of the negligible magnitude of environmental BPA pollution impacts on human health.

  1. Stochastic modeling of near-field exposure to parabens in personal care products

    DEFF Research Database (Denmark)

    Csiszar, Susan A.; Ernstoff, Alexi; Fantke, Peter

    2017-01-01

    Exposure assessment is a key step in determining risks to chemicals in consumer goods, including personal care products (PCPs). Exposure models can be used to estimate exposures to chemicals in the absence of biomonitoring data and as tools in chemical risk prioritization and screening. We apply...... a PCP exposure model based on the product intake fraction (PiF), which is defined as the fraction of chemical in a product that is taken in by the exposed population, to estimate chemical intake based on physicochemical properties and PCP usage characteristics. The PiF can be used to estimate route...... and pathway-specific exposures during both the use and disposal stages of a product. As a case study, we stochastically quantified population level exposures to parabens in PCPs, and compared estimates with biomarker values. We estimated exposure based on the usage of PCPs in the female US population, taking...

  2. Quantitative assessment of human and pet exposure to Salmonella associated with dry pet foods.

    Science.gov (United States)

    Lambertini, Elisabetta; Buchanan, Robert L; Narrod, Clare; Ford, Randall M; Baker, Robert C; Pradhan, Abani K

    2016-01-04

    Recent Salmonella outbreaks associated with dry pet foods and treats highlight the importance of these foods as previously overlooked exposure vehicles for both pets and humans. In the last decade efforts have been made to raise the safety of this class of products, for instance by upgrading production equipment, cleaning protocols, and finished product testing. However, no comprehensive or quantitative risk profile is available for pet foods, thus limiting the ability to establish safety standards and assess the effectiveness of current and proposed Salmonella control measures. This study sought to develop an ingredients-to-consumer quantitative microbial exposure assessment model to: 1) estimate pet and human exposure to Salmonella via dry pet food, and 2) assess the impact of industry and household-level mitigation strategies on exposure. Data on prevalence and concentration of Salmonella in pet food ingredients, production process parameters, bacterial ecology, and contact transfer in the household were obtained through literature review, industry data, and targeted research. A probabilistic Monte Carlo modeling framework was developed to simulate the production process and basic household exposure routes. Under the range of assumptions adopted in this model, human exposure due to handling pet food is null to minimal if contamination occurs exclusively before extrusion. Exposure increases considerably if recontamination occurs post-extrusion during coating with fat, although mean ingested doses remain modest even at high fat contamination levels, due to the low percent of fat in the finished product. Exposure is highly variable, with the distribution of doses ingested by adult pet owners spanning 3Log CFU per exposure event. Child exposure due to ingestion of 1g of pet food leads to significantly higher doses than adult doses associated with handling the food. Recontamination after extrusion and coating, e.g., via dust or equipment surfaces, may also lead to

  3. Detriment due to radiation exposure: concept and assessment

    International Nuclear Information System (INIS)

    Inaba, Jiro

    1999-01-01

    The International Commission on Radiological Protection has used a term risk' to denote the probability of a clinically observable deleterious effect such as fatal cancers and severe hereditary effects. In their 1990 recommendations ICRP developed a new term 'detriment' which contains a complex concept combining the probability, severity and time of expression of deleterious effects. Nominal probability coefficients for fatal cancer, one of the most important components of the detriment, are assessed to be 5% and 4% per Sv for the whole population and workers, respectively, for radiation protection. These values were derived from the data on mortality from the Life-Span Study of the atomic-bomb survivors up to 1985 assuming several components consist of dose-response relationship, life-span risk projection model, dose and dose rate effectiveness factor, national population and transfer model and so on. The risk estimates and each of these components include uncertainties which should be clarified for the better understanding and use of the risk estimates. However, it is not likely that near-future data from Life-Span Study will significantly change these uncertainties, which should in no way be interpreted as a denial of the essential importance of fundamental research into the mechanism of cancer induction. In these situation the National Institute of Radiological Sciences have performed a 5-year research project 'Experimental Studies on Detriments of Radiation Exposure'. The project consists of researches on a) Radiation carcinogenesis, b) Effects on embryo and fetus, c) Biological effect of plutonium. The project was successful to provide useful information on these subjects. (author)

  4. Toxicity assessment of unintentional exposure to multiple chemicals

    International Nuclear Information System (INIS)

    Mumtaz, M.M.; Ruiz, P.; De Rosa, C.T.

    2007-01-01

    Typically exposure to environmental chemicals is unintentional, and often the exposure is to chemical mixtures, either simultaneously or sequentially. When exposure occurs, in public health practice, it is prudent to ascertain if thresholds for harmful health effects are exceeded, whether by individual chemicals or by chemicals in combination. Three alternative approaches are available for assessing the toxicity of chemical mixtures. Each approach, however, has shortcomings. As the procedures of each approach are described in this paper, at various steps research needs are identified. Recently, reliance has increased on computational toxicology methods for predicting toxicological effects when data are limited. Advances in molecular biology, identification of biomarkers, and availability of accurate and sensitive methods allow us to more precisely define the relationships between multiple chemical exposures and health effects, both qualitatively and quantitatively. Key research needs are best fulfilled through collaborative research. It is through such collaborations that resources are most effectively leveraged to further develop and apply toxicity assessment methods that advance public health practices in vulnerable communities

  5. Assessment and management of chemical exposure in the Mohs laboratory.

    Science.gov (United States)

    Gunson, Todd H; Smith, Harvey R; Vinciullo, Carl

    2011-01-01

    The correct handling, storage, and disposal of chemicals used in the processing of tissue for Mohs micrographic surgery are essential. To identify the chemicals involved in the preparation of Mohs frozen sections and assess the associated occupational health risks. To quantify exposure levels of hazardous chemicals and ensure that they are minimized. A risk assessment form was completed for each chemical. Atmospheric sampling was performed at our previous laboratory for formaldehyde and volatile organic compounds. These data were used in the design of our new facility, where testing was repeated. Twenty-five chemicals were identified. Ten were classified as hazardous substances, 10 were flammable, six had specific disposal requirements, four were potential carcinogens, and three were potential teratogens. Formaldehyde readings at our previous laboratory were up to eight times the national exposure standard. Testing at the new laboratory produced levels well below the exposure standards. Chemical exposure within the Mohs laboratory can present a significant occupational hazard. Acutely toxic and potentially carcinogenic formaldehyde was found at high levels in a relatively standard laboratory configuration. A laboratory can be designed with a combination of physical environment and operational protocols that minimizes hazards and creates a safe working environment. © 2010 by the American Society for Dermatologic Surgery, Inc.

  6. Traffic-Related Air Pollution and Childhood Asthma: Recent Advances and Remaining Gaps in the Exposure Assessment Methods.

    Science.gov (United States)

    Khreis, Haneen; Nieuwenhuijsen, Mark J

    2017-03-17

    Background : Current levels of traffic-related air pollution (TRAP) are associated with the development of childhood asthma, although some inconsistencies and heterogeneity remain. An important part of the uncertainty in studies of TRAP-associated asthma originates from uncertainties in the TRAP exposure assessment and assignment methods. In this work, we aim to systematically review the exposure assessment methods used in the epidemiology of TRAP and childhood asthma, highlight recent advances, remaining research gaps and make suggestions for further research. Methods : We systematically reviewed epidemiological studies published up until 8 September 2016 and available in Embase, Ovid MEDLINE (R), and "Transport database". We included studies which examined the association between children's exposure to TRAP metrics and their risk of "asthma" incidence or lifetime prevalence, from birth to the age of 18 years old. Results : We found 42 studies which examined the associations between TRAP and subsequent childhood asthma incidence or lifetime prevalence, published since 1999. Land-use regression modelling was the most commonly used method and nitrogen dioxide (NO₂) was the most commonly used pollutant in the exposure assessments. Most studies estimated TRAP exposure at the residential address and only a few considered the participants' mobility. TRAP exposure was mostly assessed at the birth year and only a few studies considered different and/or multiple exposure time windows. We recommend that further work is needed including e.g., the use of new exposure metrics such as the composition of particulate matter, oxidative potential and ultra-fine particles, improved modelling e.g., by combining different exposure assessment models, including mobility of the participants, and systematically investigating different exposure time windows. Conclusions : Although our previous meta-analysis found statistically significant associations for various TRAP exposures and

  7. Predictions of models for environmental radiological assessment

    International Nuclear Information System (INIS)

    Peres, Sueli da Silva; Lauria, Dejanira da Costa; Mahler, Claudio Fernando

    2011-01-01

    In the field of environmental impact assessment, models are used for estimating source term, environmental dispersion and transfer of radionuclides, exposure pathway, radiation dose and the risk for human beings Although it is recognized that the specific information of local data are important to improve the quality of the dose assessment results, in fact obtaining it can be very difficult and expensive. Sources of uncertainties are numerous, among which we can cite: the subjectivity of modelers, exposure scenarios and pathways, used codes and general parameters. The various models available utilize different mathematical approaches with different complexities that can result in different predictions. Thus, for the same inputs different models can produce very different outputs. This paper presents briefly the main advances in the field of environmental radiological assessment that aim to improve the reliability of the models used in the assessment of environmental radiological impact. The intercomparison exercise of model supplied incompatible results for 137 Cs and 60 Co, enhancing the need for developing reference methodologies for environmental radiological assessment that allow to confront dose estimations in a common comparison base. The results of the intercomparison exercise are present briefly. (author)

  8. Transport of Aquatic Contaminant and Assessment of Radioecological Exposure with Spatial and Temporal Effects

    Science.gov (United States)

    Feng, Ying

    1995-01-01

    A comprehensive study of the radioecological exposure assessment for a contaminated aquatic ecosystem has been performed in this dissertation. The primary objectives of this research were to advance the understanding of radiation exposure in nature and to increase current capabilities for estimating aquatic radiation exposure with the consideration of spatial and temporal effect in nature. This was accomplished through the development of a two-dimensional aquatic exposure assessment framework and by applying the framework to the contaminated Chernobyl cooling lake (pond). This framework integrated spatial and temporal heterogeneity effects of contaminant concentration, abundance and distribution of ecosystem populations, spatial- and temporal-dependent (or density-dependent) radionuclide ingestion, and alternative food web structures. The exposure model was built on the population level to allow for the integration of density dependent population regulation into the exposure assessment. Plankton population dynamics have been integrated into the hydrodynamic-transport model to determine plankton biomass density changes and distributions. The distribution of contaminant in water was also calculated using a hydrodynamic-transport model. The significance of adding spatial and temporal effects, spatial and temporal related ecological functions, and hydrodynamics in the exposure assessment was illustrated through a series of case studies. The results suggested that the spatial and temporal heterogeneity effects of radioactive environments were substantial. Among the ecological functions considered, the food web structure was the most important contributor to the variations of fish exposure. The results obtained using a multiple prey food web structure differed by a factor of 20 from the equilibrium concentration, and by a factor of 2.5 from the concentration obtained using a single-prey food web. Impacts of changes in abundance and distribution of biomass on contaminant

  9. BYSTANDER EFFECTS, GENOMIC INSTABILITY, ADAPTIVE RESPONSE AND CANCER RISK ASSESSMENT FOR RADIATION AND CHEMICAL EXPOSURES

    Science.gov (United States)

    There is an increased interest in utilizing mechanistic data in support of the cancer risk assessment process for ionizing radiation and environmental chemical exposures. In this regard the use of biologically based dose-response models is particularly advocated. The aim is to pr...

  10. Air pollution exposure modeling of individuals

    Science.gov (United States)

    Air pollution epidemiology studies of ambient fine particulate matter (PM2.5) often use outdoor concentrations as exposure surrogates. These surrogates can induce exposure error since they do not account for (1) time spent indoors with ambient PM2.5 levels attenuated from outdoor...

  11. Matrix Population Model for Estimating Effects from Time-Varying Aquatic Exposures: Technical Documentation

    Science.gov (United States)

    The Office of Pesticide Programs models daily aquatic pesticide exposure values for 30 years in its risk assessments. However, only a fraction of that information is typically used in these assessments. The population model employed herein is a deterministic, density-dependent pe...

  12. Assessing Sources of Human Methylmercury Exposure Using Stable Mercury Isotopes

    DEFF Research Database (Denmark)

    Li, Miling; Sherman, Laura S; Blum, Joel D

    2014-01-01

    Seafood consumption is the primary route of methylmercury (MeHg) exposure for most populations. Inherent uncertainties in dietary survey data point to the need for an empirical tool to confirm exposure sources. We therefore explore the utility of Hg stable isotope ratios in human hair as a new...... method for discerning MeHg exposure sources. We characterized Hg isotope fractionation between humans and their diets using hair samples from Faroese whalers exposed to MeHg predominantly from pilot whales. We observed an increase of 1.75‰ in δ(202)Hg values between pilot whale muscle tissue and Faroese...... whalers' hair but no mass-independent fractionation. We found a similar offset in δ(202)Hg between consumed seafood and hair samples from Gulf of Mexico recreational anglers who are exposed to lower levels of MeHg from a variety of seafood sources. An isotope mixing model was used to estimate individual...

  13. A Realistic Human Exposure Assessment of Indoor Radon released from Groundwater

    International Nuclear Information System (INIS)

    Yu, Dong Han; Han, Moon Hee

    2002-01-01

    The work presents a realistic human exposure assessment of indoor radon released from groundwater in a house. At first, a two-compartment model is developed to describe the generation and transfer of radon in indoor air from groundwater. The model is used to estimate radon concentrations profile of indoor air in a house using by showering, washing clothes, and flushing toilets. Then, the study performs an uncertainty analysis of model input parameters to quantify the uncertainty in radon concentration profile. In order to estimate a daily internal dose of a specific tissue group in an adult through the inhalation of such indoor radon, a PBPK(Physiologically-Based Pharmaco-Kinetic) model is developed. Combining indoor radon profile and PBPK model is used to a realistic human assessment for such exposure. The results obtained from this study would be used to the evaluation of human risk by inhalation associated with the indoor radon released from groundwater

  14. Risk assessment of released cellulose nanocrystals – mimicking inhalatory exposure

    International Nuclear Information System (INIS)

    Endes, C; Vanhecke, D; Petri-Fink, A; Rothen-Rutishauser, B; Clift, M J D; Müller, S; Foster, E J; Weder, C; Schmid, O

    2013-01-01

    Cellulose nanocrystals (CNCs) exhibit advantageous chemical and mechanical properties that render them attractive for a wide range of applications. During the life-cycle of CNC containing materials the nanocrystals could be released and become airborne, posing a potential inhalatory exposure risk towards humans. Absent reliable and dose-controlled models that mimic this exposure in situ is a central issue in gaining an insight into the CNC-lung interaction. Here, an Air Liquid Interface Cell Exposure system (ALICE), previously designed for studies of spherical nanoparticles, was used for the first time to establish a realistic physiological exposure test method for inhaled fiber shaped nano-objects; in this case, CNCs isolated from cotton. Applying a microscopy based approach the spatially homogenous deposition of CNCs was demonstrated as a prerequisite of the functioning of the ALICE. Furthermore, reliability and controllability of the system to nebulise high aspect ratio nanomaterials (HARN, e.g. CNCs) was shown. This opens the potential to thoroughly investigate the inhalatory risk of CNCs in vitro using a realistic exposure system.

  15. Final report on the Project Research 'Assessment of Human Exposure to Environmental Radiation'

    International Nuclear Information System (INIS)

    1989-03-01

    This is the final report of the Project Research, 'Assessment of Human Exposure to Environmental Radiation', which has been conducted during the period 1983-1988. With the objective of assessing risk of environmental radioactivity to the population, the Project was divided into the following five research groups: (1) research for establishing calculation models and parameters in transfer of radionuclides from crop species through the human body; (2) research for analyzing transfer of radionuclides in the ocean and their contributions to exposure doses in the human body; (3) research for surveying accuracy of exposure models for the external body and respiratory organ and the influential factors; (4) research for determining uptake and biokinetics of radionuclides in the body; and (5) research for estimating and evaluating physical and physiological characteristics of reference Japanese man and the populaltion doses. Effluents from nuclear power plants and reprocessing plants were regarded as radionuclide sources in the water and atmosphere. (N.K.)

  16. Risk of breast cancer following exposure to tetrachloroethylene-contaminated drinking water in Cape Cod, Massachusetts: reanalysis of a case-control study using a modified exposure assessment

    Directory of Open Access Journals (Sweden)

    Webster Thomas F

    2011-05-01

    Full Text Available Abstract Background Tetrachloroethylene (PCE is an important occupational chemical used in metal degreasing and drycleaning and a prevalent drinking water contaminant. Exposure often occurs with other chemicals but it occurred alone in a pattern that reduced the likelihood of confounding in a unique scenario on Cape Cod, Massachusetts. We previously found a small to moderate increased risk of breast cancer among women with the highest exposures using a simple exposure model. We have taken advantage of technical improvements in publically available software to incorporate a more sophisticated determination of water flow and direction to see if previous results were robust to more accurate exposure assessment. Methods The current analysis used PCE exposure estimates generated with the addition of water distribution modeling software (EPANET 2.0 to test model assumptions, compare exposure distributions to prior methods, and re-examine the risk of breast cancer. In addition, we applied data smoothing to examine nonlinear relationships between breast cancer and exposure. We also compared a set of measured PCE concentrations in water samples collected in 1980 to modeled estimates. Results Thirty-nine percent of individuals considered unexposed in prior epidemiological analyses were considered exposed using the current method, but mostly at low exposure levels. As a result, the exposure distribution was shifted downward resulting in a lower value for the 90th percentile, the definition of "high exposure" in prior analyses. The current analyses confirmed a modest increase in the risk of breast cancer for women with high PCE exposure levels defined by either the 90th percentile (adjusted ORs 1.0-1.5 for 0-19 year latency assumptions or smoothing analysis cut point (adjusted ORs 1.3-2.0 for 0-15 year latency assumptions. Current exposure estimates had a higher correlation with PCE concentrations in water samples (Spearman correlation coefficient = 0.65, p

  17. Long- and short-term exposure to PM2.5 and mortality: using novel exposure models.

    Science.gov (United States)

    Kloog, Itai; Ridgway, Bill; Koutrakis, Petros; Coull, Brent A; Schwartz, Joel D

    2013-07-01

    Many studies have reported associations between ambient particulate matter (PM) and adverse health effects, focused on either short-term (acute) or long-term (chronic) PM exposures. For chronic effects, the studied cohorts have rarely been representative of the population. We present a novel exposure model combining satellite aerosol optical depth and land-use data to investigate both the long- and short-term effects of PM2.5 exposures on population mortality in Massachusetts, United States, for the years 2000-2008. All deaths were geocoded. We performed two separate analyses: a time-series analysis (for short-term exposure) where counts in each geographic grid cell were regressed against cell-specific short-term PM2.5 exposure, temperature, socioeconomic data, lung cancer rates (as a surrogate for smoking), and a spline of time (to control for season and trends). In addition, for long-term exposure, we performed a relative incidence analysis using two long-term exposure metrics: regional 10 × 10 km PM2.5 predictions and local deviations from the cell average based on land use within 50 m of the residence. We tested whether these predicted the proportion of deaths from PM-related causes (cardiovascular and respiratory diseases). For short-term exposure, we found that for every 10-µg/m increase in PM 2.5 exposure there was a 2.8% increase in PM-related mortality (95% confidence interval [CI] = 2.0-3.5). For the long-term exposure at the grid cell level, we found an odds ratio (OR) for every 10-µg/m increase in long-term PM2.5 exposure of 1.6 (CI = 1.5-1.8) for particle-related diseases. Local PM2.5 had an OR of 1.4 (CI = 1.3-1.5), which was independent of and additive to the grid cell effect. We have developed a novel PM2.5 exposure model based on remote sensing data to assess both short- and long-term human exposures. Our approach allows us to gain spatial resolution in acute effects and an assessment of long-term effects in the entire population rather than a

  18. An assessment of air pollutant exposure methods in Mexico City, Mexico.

    Science.gov (United States)

    Rivera-González, Luis O; Zhang, Zhenzhen; Sánchez, Brisa N; Zhang, Kai; Brown, Daniel G; Rojas-Bracho, Leonora; Osornio-Vargas, Alvaro; Vadillo-Ortega, Felipe; O'Neill, Marie S

    2015-05-01

    Geostatistical interpolation methods to estimate individual exposure to outdoor air pollutants can be used in pregnancy cohorts where personal exposure data are not collected. Our objectives were to a) develop four assessment methods (citywide average (CWA); nearest monitor (NM); inverse distance weighting (IDW); and ordinary Kriging (OK)), and b) compare daily metrics and cross-validations of interpolation models. We obtained 2008 hourly data from Mexico City's outdoor air monitoring network for PM10, PM2.5, O3, CO, NO2, and SO2 and constructed daily exposure metrics for 1,000 simulated individual locations across five populated geographic zones. Descriptive statistics from all methods were calculated for dry and wet seasons, and by zone. We also evaluated IDW and OK methods' ability to predict measured concentrations at monitors using cross validation and a coefficient of variation (COV). All methods were performed using SAS 9.3, except ordinary Kriging which was modeled using R's gstat package. Overall, mean concentrations and standard deviations were similar among the different methods for each pollutant. Correlations between methods were generally high (r=0.77 to 0.99). However, ranges of estimated concentrations determined by NM, IDW, and OK were wider than the ranges for CWA. Root mean square errors for OK were consistently equal to or lower than for the IDW method. OK standard errors varied considerably between pollutants and the computed COVs ranged from 0.46 (least error) for SO2 and PM10 to 3.91 (most error) for PM2.5. OK predicted concentrations measured at the monitors better than IDW and NM. Given the similarity in results for the exposure methods, OK is preferred because this method alone provides predicted standard errors which can be incorporated in statistical models. The daily estimated exposures calculated using these different exposure methods provide flexibility to evaluate multiple windows of exposure during pregnancy, not just trimester or

  19. NASA Space Radiation Protection Strategies: Risk Assessment and Permissible Exposure Limits

    Science.gov (United States)

    Huff, J. L.; Patel, Z. S.; Simonsen, L. C.

    2017-01-01

    Permissible exposure limits (PELs) for short-term and career astronaut exposures to space radiation have been set and approved by NASA with the goal of protecting astronauts against health risks associated with ionizing radiation exposure. Short term PELs are intended to prevent clinically significant deterministic health effects, including performance decrements, which could threaten astronaut health and jeopardize mission success. Career PELs are implemented to control late occurring health effects, including a 3% risk of exposure induced death (REID) from cancer, and dose limits are used to prevent cardiovascular and central nervous system diseases. For radiation protection, meeting the cancer PEL is currently the design driver for galactic cosmic ray and solar particle event shielding, mission duration, and crew certification (e.g., 1-year ISS missions). The risk of cancer development is the largest known long-term health consequence following radiation exposure, and current estimates for long-term health risks due to cardiovascular diseases are approximately 30% to 40% of the cancer risk for exposures above an estimated threshold (Deep Space one-year and Mars missions). Large uncertainties currently exist in estimating the health risks of space radiation exposure. Improved understanding through radiobiology and physics research allows increased accuracy in risk estimation and is essential for ensuring astronaut health as well as for controlling mission costs, optimization of mission operations, vehicle design, and countermeasure assessment. We will review the Space Radiation Program Element's research strategies to increase accuracy in risk models and to inform development and validation of the permissible exposure limits.

  20. Inhalation Exposure Input Parameters for the Biosphere Model

    Energy Technology Data Exchange (ETDEWEB)

    K. Rautenstrauch

    2004-09-10

    This analysis is one of 10 reports that support the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN) biosphere model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the conceptual model as well as the mathematical model and its input parameters. This report documents development of input parameters for the biosphere model that are related to atmospheric mass loading and supports the use of the model to develop biosphere dose conversion factors (BDCFs). The biosphere model is one of a series of process models supporting the total system performance assessment (TSPA) for a Yucca Mountain repository. Inhalation Exposure Input Parameters for the Biosphere Model is one of five reports that develop input parameters for the biosphere model. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling, and the plan for development of the biosphere abstraction products for TSPA, as identified in the Technical Work Plan for Biosphere Modeling and Expert Support (BSC 2004 [DIRS 169573]). This analysis report defines and justifies values of mass loading for the biosphere model. Mass loading is the total mass concentration of resuspended particles (e.g., dust, ash) in a volume of air. Mass loading values are used in the air submodel of ERMYN to calculate concentrations of radionuclides in air inhaled by a receptor and concentrations in air surrounding crops. Concentrations in air to which the receptor is exposed are then used in the inhalation submodel to calculate the dose contribution to the receptor from inhalation of contaminated airborne particles. Concentrations in air surrounding plants are used in the plant submodel to calculate the concentrations of radionuclides in foodstuffs contributed from uptake by foliar interception.

  1. Inhalation Exposure Input Parameters for the Biosphere Model

    International Nuclear Information System (INIS)

    K. Rautenstrauch

    2004-01-01

    This analysis is one of 10 reports that support the Environmental Radiation Model for Yucca Mountain, Nevada (ERMYN) biosphere model. The ''Biosphere Model Report'' (BSC 2004 [DIRS 169460]) describes in detail the conceptual model as well as the mathematical model and its input parameters. This report documents development of input parameters for the biosphere model that are related to atmospheric mass loading and supports the use of the model to develop biosphere dose conversion factors (BDCFs). The biosphere model is one of a series of process models supporting the total system performance assessment (TSPA) for a Yucca Mountain repository. Inhalation Exposure Input Parameters for the Biosphere Model is one of five reports that develop input parameters for the biosphere model. A graphical representation of the documentation hierarchy for the ERMYN is presented in Figure 1-1. This figure shows the interrelationships among the products (i.e., analysis and model reports) developed for biosphere modeling, and the plan for development of the biosphere abstraction products for TSPA, as identified in the Technical Work Plan for Biosphere Modeling and Expert Support (BSC 2004 [DIRS 169573]). This analysis report defines and justifies values of mass loading for the biosphere model. Mass loading is the total mass concentration of resuspended particles (e.g., dust, ash) in a volume of air. Mass loading values are used in the air submodel of ERMYN to calculate concentrations of radionuclides in air inhaled by a receptor and concentrations in air surrounding crops. Concentrations in air to which the receptor is exposed are then used in the inhalation submodel to calculate the dose contribution to the receptor from inhalation of contaminated airborne particles. Concentrations in air surrounding plants are used in the plant submodel to calculate the concentrations of radionuclides in foodstuffs contributed from uptake by foliar interception

  2. Health and exposure assessment of flare gas emissions

    International Nuclear Information System (INIS)

    Kindzierski, W.B.; Byrne-Lewis, C.; Probert, S.

    2000-01-01

    The incomplete combustion of flare gases produces pollutants such as volatile organic compounds (VOCs) and polycyclic aromatic hydrocarbons (PAHs) which are cause for concern for public health. Some of the concerns relate to potential long-term cumulative health effects from exposure to hazardous air pollutants including benzene, styrene, naphthalene, and benzopyrene. This study demonstrated that several factors should be taken into account when considering the importance of flaring and human exposure to flare gas emissions. Most flare stacks are located in rural areas, but most time-availability studies have been done on urban populations where the majority of people spend their time indoors. It was recommended that more time-activity studies are needed to emphasize the behaviour of rural populations which are most susceptible to exposure from pollutants from flaring. It was concluded that higher indoor air concentrations exist for many VOCs and PAHs compared to outdoors, but in these instances, indoor sources are the major contributors to indoor air concentrations. It was recommended that health assessments of hazardous air pollutants emitted from gas flaring has to take into account the indoor setting and other background exposures in order to provide useful information for decision makers. 49 refs., 8 tabs., 1 fig

  3. Assessing public exposure in commercial flights in Brazil

    Energy Technology Data Exchange (ETDEWEB)

    Alves, Vanusa A.; Rochedo, Elaine R.R.; Damasceno, Nadya M.P., E-mail: vanusa_abreu@ymail.com, E-mail: elainerochedo@gmail.com, E-mail: nadya@ime.eb.br [Instituto Militar de Engenharia (IME), Rio de Janeiro, RJ (Brazil); Silva, Diogo N.G., E-mail: diogongs@gmail.com [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The exposure to cosmic radiation from air traveling is significantly higher than that at ground level, varying according to the route due to the effect of latitude and flight time, to the flight altitude, due to the type of airplane and to the year, due to the effect of solar cycle on the galactic cosmic rays flux. The computer code CARI-6, developed by the U.S. Federal Aviation Administration, is aimed to calculate the effective dose of galactic cosmic radiation received by an individual in an airplane, flying the shortest route between two airports in the world. The objective of this work is to estimate the contribution of the exposure to cosmic radiation on domestic commercial flights for the Brazilian customers. The work shall serve as a baseline for future comparisons of the growth of civil aviation in the country. It shall also open perspectives for discussions on the concept of risk and its public acceptance, relevant to the establishment of radiological protection guidelines. Average effective doses for individual flights ranged from 0.2 to 8.8 μSv. This is a very small contribution to average overall exposure to natural background radiation (2.4 mSv/y). Doses for the most frequent flight routes in the country have been assessed. These include flights to and from Rio de Janeiro, Sao Paulo and Brasilia. Doses for frequent flyers and collective doses are discussed in perspective of other exposure sources. (author)

  4. Assessing public exposure in commercial flights in Brazil

    International Nuclear Information System (INIS)

    Alves, Vanusa A.; Rochedo, Elaine R.R.; Damasceno, Nadya M.P.; Silva, Diogo N.G.

    2013-01-01

    The exposure to cosmic radiation from air traveling is significantly higher than that at ground level, varying according to the route due to the effect of latitude and flight time, to the flight altitude, due to the type of airplane and to the year, due to the effect of solar cycle on the galactic cosmic rays flux. The computer code CARI-6, developed by the U.S. Federal Aviation Administration, is aimed to calculate the effective dose of galactic cosmic radiation received by an individual in an airplane, flying the shortest route between two airports in the world. The objective of this work is to estimate the contribution of the exposure to cosmic radiation on domestic commercial flights for the Brazilian customers. The work shall serve as a baseline for future comparisons of the growth of civil aviation in the country. It shall also open perspectives for discussions on the concept of risk and its public acceptance, relevant to the establishment of radiological protection guidelines. Average effective doses for individual flights ranged from 0.2 to 8.8 μSv. This is a very small contribution to average overall exposure to natural background radiation (2.4 mSv/y). Doses for the most frequent flight routes in the country have been assessed. These include flights to and from Rio de Janeiro, Sao Paulo and Brasilia. Doses for frequent flyers and collective doses are discussed in perspective of other exposure sources. (author)

  5. Human health risk assessment related to cyanotoxins exposure.

    Science.gov (United States)

    Funari, Enzo; Testai, Emanuela

    2008-01-01

    This review focuses on the risk assessment associated with human exposure to cyanotoxins, secondary metabolites of an ubiquitous group of photosynthetic procariota. Cyanobacteria occur especially in eutrophic inland and coastal surface waters, where under favorable conditions they attain high densities and may form blooms and scums. Cyanotoxins can be grouped according to their biological effects into hepatotoxins, neurotoxins, cytotoxins, and toxins with irritating potential, also acting on the gastrointestinal system. The chemical and toxicological properties of the main cyanotoxins, relevant for the evaluation of possible risks for human health, are presented. Humans may be exposed to cyanotoxins via several routes, with the oral one being by far the most important, occurring by ingesting contaminated drinking water, food, some dietary supplements, or water during recreational activities. Acute and short-term toxic effects have been associated in humans with exposure to high levels of cyanotoxins in drinking and bathing waters. However, the chronic exposure to low cyanotoxin levels remains a critical issue. This article identifies the actual risky exposure scenarios, provides toxicologically derived reference values, and discusses open issues and research needs.

  6. CalTOX, a multimedia total exposure model for hazardous-waste sites

    International Nuclear Information System (INIS)

    McKone, T.E.

    1993-06-01

    CalTOX has been developed as a spreadsheet model to assist in health-risk assessments that address contaminated soils and the contamination of adjacent air, surface water, sediments, and ground water. The modeling effort includes a multimedia transport and transformation model, exposure scenario models, and efforts to quantify and reduce uncertainty in multimedia, multiple-pathway exposure models. This report provides an overview of the CalTOX model components, lists the objectives of the model, describes the philosophy under which the model was developed, identifies the chemical classes for which the model can be used, and describes critical sensitivities and uncertainties. The multimedia transport and transformation model is a dynamic model that can be used to assess time-varying concentrations of contaminants introduced initially to soil layers or for contaminants released continuously to air or water. This model assists the user in examining how chemical and landscape properties impact both the ultimate route and quantity of human contact. Multimedia, multiple pathway exposure models are used in the CalTOX model to estimate average daily potential doses within a human population in the vicinity of a hazardous substances release site. The exposure models encompass twenty-three exposure pathways. The exposure assessment process consists of relating contaminant concentrations in the multimedia model compartments to contaminant concentrations in the media with which a human population has contact (personal air, tap water, foods, household dusts soils, etc.). The average daily dose is the product of the exposure concentrations in these contact media and an intake or uptake factor that relates the concentrations to the distributions of potential dose within the population

  7. Pesticide Exposure, Safety Issues, and Risk Assessment Indicators

    Science.gov (United States)

    Damalas, Christos A.; Eleftherohorinos, Ilias G.

    2011-01-01

    Pesticides are widely used in agricultural production to prevent or control pests, diseases, weeds, and other plant pathogens in an effort to reduce or eliminate yield losses and maintain high product quality. Although pesticides are developed through very strict regulation processes to function with reasonable certainty and minimal impact on human health and the environment, serious concerns have been raised about health risks resulting from occupational exposure and from residues in food and drinking water. Occupational exposure to pesticides often occurs in the case of agricultural workers in open fields and greenhouses, workers in the pesticide industry, and exterminators of house pests. Exposure of the general population to pesticides occurs primarily through eating food and drinking water contaminated with pesticide residues, whereas substantial exposure can also occur in or around the home. Regarding the adverse effects on the environment (water, soil and air contamination from leaching, runoff, and spray drift, as well as the detrimental effects on wildlife, fish, plants, and other non-target organisms), many of these effects depend on the toxicity of the pesticide, the measures taken during its application, the dosage applied, the adsorption on soil colloids, the weather conditions prevailing after application, and how long the pesticide persists in the environment. Therefore, the risk assessment of the impact of pesticides either on human health or on the environment is not an easy and particularly accurate process because of differences in the periods and levels of exposure, the types of pesticides used (regarding toxicity and persistence), and the environmental characteristics of the areas where pesticides are usually applied. Also, the number of the criteria used and the method of their implementation to assess the adverse effects of pesticides on human health could affect risk assessment and would possibly affect the characterization of the already

  8. Pesticide Exposure, Safety Issues, and Risk Assessment Indicators

    Directory of Open Access Journals (Sweden)

    Christos A. Damalas

    2011-05-01

    Full Text Available Pesticides are widely used in agricultural production to prevent or control pests, diseases, weeds, and other plant pathogens in an effort to reduce or eliminate yield losses and maintain high product quality. Although pesticides are developed through very strict regulation processes to function with reasonable certainty and minimal impact on human health and the environment, serious concerns have been raised about health risks resulting from occupational exposure and from residues in food and drinking water. Occupational exposure to pesticides often occurs in the case of agricultural workers in open fields and greenhouses, workers in the pesticide industry, and exterminators of house pests. Exposure of the general population to pesticides occurs primarily through eating food and drinking water contaminated with pesticide residues, whereas substantial exposure can also occur in or around the home. Regarding the adverse effects on the environment (water, soil and air contamination from leaching, runoff, and spray drift, as well as the detrimental effects on wildlife, fish, plants, and other non-target organisms, many of these effects depend on the toxicity of the pesticide, the measures taken during its application, the dosage applied, the adsorption on soil colloids, the weather conditions prevailing after application, and how long the pesticide persists in the environment. Therefore, the risk assessment of the impact of pesticides either on human health or on the environment is not an easy and particularly accurate process because of differences in the periods and levels of exposure, the types of pesticides used (regarding toxicity and persistence, and the environmental characteristics of the areas where pesticides are usually applied. Also, the number of the criteria used and the method of their implementation to assess the adverse effects of pesticides on human health could affect risk assessment and would possibly affect the characterization

  9. Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models

    Science.gov (United States)

    Laurier, Dominique; Rage, Estelle

    2018-01-01

    Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies. PMID:29408862

  10. A review of models for near-field exposure pathways of chemicals in consumer products

    DEFF Research Database (Denmark)

    Huang, Lei; Ernstoff, Alexi; Fantke, Peter

    2017-01-01

    able to quantify the multiple transfers of chemicals from products used near-field to humans. The present review therefore aims at an in-depth overview of modeling approaches for near-field chemical release and human exposure pathways associated with consumer products. It focuses on lower......-tier, mechanistic models suitable for life cycle assessments (LCA), chemical alternative assessment (CAA) and high-throughput screening risk assessment (HTS). Chemicals in a product enter the near-field via a defined “compartment of entry”, are transformed or transferred to adjacent compartments, and eventually end......Exposure to chemicals in consumer products has been gaining increasing attention, with multiple studies showing that near-field exposures from products is high compared to far-field exposures. Regarding the numerous chemical-product combinations, there is a need for an overarching review of models...

  11. Modelling ecological and human exposure to POPs in Venice lagoon - Part II: Quantitative uncertainty and sensitivity analysis in coupled exposure models.

    Science.gov (United States)

    Radomyski, Artur; Giubilato, Elisa; Ciffroy, Philippe; Critto, Andrea; Brochot, Céline; Marcomini, Antonio

    2016-11-01

    The study is focused on applying uncertainty and sensitivity analysis to support the application and evaluation of large exposure models where a significant number of parameters and complex exposure scenarios might be involved. The recently developed MERLIN-Expo exposure modelling tool was applied to probabilistically assess the ecological and human exposure to PCB 126 and 2,3,7,8-TCDD in the Venice lagoon (Italy). The 'Phytoplankton', 'Aquatic Invertebrate', 'Fish', 'Human intake' and PBPK models available in MERLIN-Expo library were integrated to create a specific food web to dynamically simulate bioaccumulation in various aquatic species and in the human body over individual lifetimes from 1932 until 1998. MERLIN-Expo is a high tier exposure modelling tool allowing propagation of uncertainty on the model predictions through Monte Carlo simulation. Uncertainty in model output can be further apportioned between parameters by applying built-in sensitivity analysis tools. In this study, uncertainty has been extensively addressed in the distribution functions to describe the data input and the effect on model results by applying sensitivity analysis techniques (screening Morris method, regression analysis, and variance-based method EFAST). In the exposure scenario developed for the Lagoon of Venice, the concentrations of 2,3,7,8-TCDD and PCB 126 in human blood turned out to be mainly influenced by a combination of parameters (half-lives of the chemicals, body weight variability, lipid fraction, food assimilation efficiency), physiological processes (uptake/elimination rates), environmental exposure concentrations (sediment, water, food) and eating behaviours (amount of food eaten). In conclusion, this case study demonstrated feasibility of MERLIN-Expo to be successfully employed in integrated, high tier exposure assessment. Copyright © 2016 Elsevier B.V. All rights reserved.

  12. Data Sources Available for Modeling Environmental Exposures in Older Adults

    Science.gov (United States)

    This report, “Data Sources Available for Modeling Environmental Exposures in Older Adults,” focuses on information sources and data available for modeling environmental exposures in the older U.S. population, defined here to be people 60 years and older, with an emphasis on those...

  13. Modeling and Characterization of the Uplink and Downlink Exposure in Wireless Networks

    Directory of Open Access Journals (Sweden)

    Anis Krayni

    2017-01-01

    Full Text Available This paper deals with a new methodology to assess the exposure induced by both uplink and downlink of a cellular network using 3D electromagnetic simulations. It aims to analyze together the exposure induced by a personal device (uplink exposure and that induced by a base station (downlink exposure. The study involved the major parameters contributing to variability and uncertainty in exposure assessment, such as the user’s posture, the type of wireless device, and the propagation environment. Our approach is relying basically on the modeling of the power radiated by the personal device and the ambient electric field, while taking into account the effects of human body shadowing and the propagation channel fluctuations. The exposure assessment as well as the human-wave interactions has been simulated using the finite difference in time domain method (FDTD. In uplink scenarios, four FDTD simulations were performed with a child model, used in two postures (sitting and standing and in two usage scenarios (voice and data, which aimed to examine the exposure induced by a mobile phone and a tablet emitting, respectively, at 900 MHz and 1940 MHz. In the downlink scenario, a series of FDTD simulations of an exposure to a single plane wave and multiplane waves have been conducted, and an efficient metamodeling of the exposure using the Polynomial Chaos approach has been developed.

  14. Cea-Expo: A facility exposure matrix to assess passed exposure to chemical carcinogens and radionuclides of nuclear workers

    International Nuclear Information System (INIS)

    Telle-Lamberton, M.; Bouville, P.; Bergot, D.; Gagneau, M.; Marot, S.; Telle-Lamberton, M.; Giraud, J.M.; Gelas, J.M.

    2005-01-01

    A 'Facility-Exposure Matrix' (FEM) is proposed to assess exposure to chemical carcinogens and radionuclides in a cohort of nuclear workers. Exposures are to be attributed in the following way: a worker reports to an administrative unit and/or is monitored for exposure to ionising radiation in a specific workplace. These units are connected with a list of facilities for which exposure is assessed through a group of experts. The entire process of the FEM applied in one of the nuclear centres included in the study shows that the FEM is feasible: exposure durations as well as groups of correlated exposures are presented but have to be considered as possible rather than positive exposures. Considering the number of facilities to assess (330), ways to simplify the method are proposed: (i) the list of exposures will be restricted to 18 chemical products retained from an extensive bibliography study; (ii) for each of the following classes of facilities: nuclear reactors, fuel fabrication, high-activity laboratories and radiation chemistry, accelerators and irradiators, waste treatment, biology, reprocessing, fusion, occupational exposure will be deduced from the information already gathered by the initial method. Besides taking into account confusion factors in the low doses epidemiological study of nuclear workers, the matrix should help in the assessment of internal contamination and chemical exposures in the nuclear industry. (author)

  15. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

    International Nuclear Information System (INIS)

    Teng, S.; Tebby, C.; Barcellini-Couget, S.; De Sousa, G.; Brochot, C.; Rahmani, R.; Pery, A.R.R.

    2016-01-01

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.

  16. Analysis of real-time mixture cytotoxicity data following repeated exposure using BK/TD models

    Energy Technology Data Exchange (ETDEWEB)

    Teng, S.; Tebby, C. [Models for Toxicology and Ecotoxicology Unit, INERIS, Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Barcellini-Couget, S. [ODESIA Neosciences, Sophia Antipolis, 400 route des chappes, 06903 Sophia Antipolis (France); De Sousa, G. [INRA, ToxAlim, 400 route des Chappes, BP, 167 06903 Sophia Antipolis, Cedex (France); Brochot, C. [Models for Toxicology and Ecotoxicology Unit, INERIS, Parc Technologique Alata, BP 2, 60550 Verneuil-en-Halatte (France); Rahmani, R. [INRA, ToxAlim, 400 route des Chappes, BP, 167 06903 Sophia Antipolis, Cedex (France); Pery, A.R.R., E-mail: alexandre.pery@agroparistech.fr [AgroParisTech, UMR 1402 INRA-AgroParisTech Ecosys, 78850 Thiverval Grignon (France); INRA, UMR 1402 INRA-AgroParisTech Ecosys, 78850 Thiverval Grignon (France)

    2016-08-15

    Cosmetic products generally consist of multiple ingredients. Thus, cosmetic risk assessment has to deal with mixture toxicity on a long-term scale which means it has to be assessed in the context of repeated exposure. Given that animal testing has been banned for cosmetics risk assessment, in vitro assays allowing long-term repeated exposure and adapted for in vitro – in vivo extrapolation need to be developed. However, most in vitro tests only assess short-term effects and consider static endpoints which hinder extrapolation to realistic human exposure scenarios where concentration in target organs is varies over time. Thanks to impedance metrics, real-time cell viability monitoring for repeated exposure has become possible. We recently constructed biokinetic/toxicodynamic models (BK/TD) to analyze such data (Teng et al., 2015) for three hepatotoxic cosmetic ingredients: coumarin, isoeugenol and benzophenone-2. In the present study, we aim to apply these models to analyze the dynamics of mixture impedance data using the concepts of concentration addition and independent action. Metabolic interactions between the mixture components were investigated, characterized and implemented in the models, as they impacted the actual cellular exposure. Indeed, cellular metabolism following mixture exposure induced a quick disappearance of the compounds from the exposure system. We showed that isoeugenol substantially decreased the metabolism of benzophenone-2, reducing the disappearance of this compound and enhancing its in vitro toxicity. Apart from this metabolic interaction, no mixtures showed any interaction, and all binary mixtures were successfully modeled by at least one model based on exposure to the individual compounds. - Highlights: • We could predict cell response over repeated exposure to mixtures of cosmetics. • Compounds acted independently on the cells. • Metabolic interactions impacted exposure concentrations to the compounds.

  17. Irrigation in dose assessments models

    Energy Technology Data Exchange (ETDEWEB)

    Bergstroem, Ulla; Barkefors, Catarina [Studsvik RadWaste AB, Nykoeping (Sweden)

    2004-05-01

    dominating contribution to resulting concentrations of radionuclides in vegetation due to irrigation. Finally a proposal is given how to model irrigation in future assessments by using an expression taking into account the leaf area index (LAI) and a specific storage capacity. In addition differentiation of retention on vegetation surfaces for various elements is proposed due to information in the literature. It has been stated that cations are retained more effectively than anions. Most radioecological models describe migration of radionuclides in soils by an expression including advection and bioturbation as main processes. A sensitivity and uncertainty analysis was performed for the expression used in SR 97 and SAFE to describe this. The results show, as expected, that for immobile radionuclides bioturbation causes a higher transport than advection, while for mobile radionuclides bioturbation is negligible. Irrigation is important from an exposure point of view. The importance varies due to element and consumption rates. Interception on vegetation surfaces and subsequent retention give the highest contamination for elements with low bioavailability.

  18. Irrigation in dose assessments models

    International Nuclear Information System (INIS)

    Bergstroem, Ulla; Barkefors, Catarina

    2004-05-01

    dominating contribution to resulting concentrations of radionuclides in vegetation due to irrigation. Finally a proposal is given how to model irrigation in future assessments by using an expression taking into account the leaf area index (LAI) and a specific storage capacity. In addition differentiation of retention on vegetation surfaces for various elements is proposed due to information in the literature. It has been stated that cations are retained more effectively than anions. Most radioecological models describe migration of radionuclides in soils by an expression including advection and bioturbation as main processes. A sensitivity and uncertainty analysis was performed for the expression used in SR 97 and SAFE to describe this. The results show, as expected, that for immobile radionuclides bioturbation causes a higher transport than advection, while for mobile radionuclides bioturbation is negligible. Irrigation is important from an exposure point of view. The importance varies due to element and consumption rates. Interception on vegetation surfaces and subsequent retention give the highest contamination for elements with low bioavailability

  19. A quantitative screening-level approach to incorporate chemical exposure and risk into alternative assessment evaluations.

    Science.gov (United States)

    Arnold, Scott M; Greggs, Bill; Goyak, Katy O; Landenberger, Bryce D; Mason, Ann M; Howard, Brett; Zaleski, Rosemary T

    2017-11-01

    As the general public and retailers ask for disclosure of chemical ingredients in the marketplace, a number of hazard screening tools were developed to evaluate the so-called "greenness" of individual chemical ingredients and/or formulations. The majority of these tools focus only on hazard, often using chemical lists, ignoring the other part of the risk equation: exposure. Using a hazard-only focus can result in regrettable substitutions, changing 1 chemical ingredient for another that turns out to be more hazardous or shifts the toxicity burden to others. To minimize the incidents of regrettable substitutions, BizNGO describes "Common Principles" to frame a process for informed substitution. Two of these 6 principles are: "reduce hazard" and "minimize exposure." A number of frameworks have emerged to evaluate and assess alternatives. One framework developed by leading experts under the auspices of the US National Academy of Sciences recommended that hazard and exposure be specifically addressed in the same step when assessing candidate alternatives. For the alternative assessment community, this article serves as an informational resource for considering exposure in an alternatives assessment using elements of problem formulation; product identity, use, and composition; hazard analysis; exposure analysis; and risk characterization. These conceptual elements build on practices from government, academia, and industry and are exemplified through 2 hypothetical case studies demonstrating the questions asked and decisions faced in new product development. These 2 case studies-inhalation exposure to a generic paint product and environmental exposure to a shampoo rinsed down the drain-demonstrate the criteria, considerations, and methods required to combine exposure models addressing human health and environmental impacts to provide a screening level hazard and exposure (risk) analysis. This article informs practices for these elements within a comparative risk context

  20. What are the elements required to improve exposure estimates in life cycle assessments?

    DEFF Research Database (Denmark)

    Ernstoff, Alexi; Rosenbaum, Ralph K.; Margni, Manuele

    2016-01-01

    human toxicity and ecosystem toxicity of chemicals posed by different product life cycle stages are characterized in the life cycle impact assessment (LCIA) phase. Exposure and effect quantification as part of LCIA toxicity characterization faces numerous challenges related to inventory analysis (e.......g. number and quantity of chemicals emitted), substance-specific modelling (e.g. organics, inorganics, nano-materials) in various environments and time horizons, human and ecosystem exposure quantification (e.g. exposed organisms and exposure pathways), and toxicity end-points (e.g. carcinogenicity...... chemical exposure and harmful effects. Thereby, we structure this study of key elements identified as areas of elevated public, industrial, regulatory, and scientific concerns. We found the majority of missing elements are directly related to the definition of exposed populations (both ecosystems...

  1. Physiologically based pharmacokinetic toolkit to evaluate environmental exposures: Applications of the dioxin model to study real life exposures

    Energy Technology Data Exchange (ETDEWEB)

    Emond, Claude, E-mail: claude.emond@biosmc.com [BioSimulation Consulting Inc, Newark, DE (United States); Ruiz, Patricia; Mumtaz, Moiz [Division of Toxicology and Human Health Sciences, Agency for Toxic Substances and Disease Registry, Atlanta, GA (United States)

    2017-01-15

    Chlorinated dibenzo-p-dioxins (CDDs) are a series of mono- to octa-chlorinated homologous chemicals commonly referred to as polychlorinated dioxins. One of the most potent, well-known, and persistent member of this family is 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). As part of translational research to make computerized models accessible to health risk assessors, we present a Berkeley Madonna recoded version of the human physiologically based pharmacokinetic (PBPK) model used by the U.S. Environmental Protection Agency (EPA) in the recent dioxin assessment. This model incorporates CYP1A2 induction, which is an important metabolic vector that drives dioxin distribution in the human body, and it uses a variable elimination half-life that is body burden dependent. To evaluate the model accuracy, the recoded model predictions were compared with those of the original published model. The simulations performed with the recoded model matched well with those of the original model. The recoded model was then applied to available data sets of real life exposure studies. The recoded model can describe acute and chronic exposures and can be useful for interpreting human biomonitoring data as part of an overall dioxin and/or dioxin-like compounds risk assessment. - Highlights: • The best available dioxin PBPK model for interpreting human biomonitoring data is presented. • The original PBPK model was recoded from acslX to the Berkeley Madonna (BM) platform. • Comparisons were made of the accuracy of the recoded model with the original model. • The model is a useful addition to the ATSDR's BM based PBPK toolkit that supports risk assessors. • The application of the model to real-life exposure data sets is illustrated.

  2. Assessment of Nicotine Exposure From Active Human Cigarette Smoking Time

    Directory of Open Access Journals (Sweden)

    Cahours Xavier

    2017-09-01

    Full Text Available The burning of a cigarette is a series of consecutive sequences of both passive and active burnings when a smoking cycle is applied to the cigarette. A previous study, using a smoking machine, showed that cigarette nicotine yields are dependent linearly on the difference between the time of smouldering (passive burning and the time of smoking (active burning. It is predicted that the smoker’s nicotine yield increases when the intensity of smoking increases, i.e., when the time to smoke a cigarette (smoking time decreases. Note that observations made on machines might not be comparable to human behaviours. The aim of this study was to determine whether nicotine mouth-level exposure could be predicted through measurement of human smoking time. A smoking behaviour study was conducted to compare human smoking nicotine yields obtained from both filter tip analysis and the cigarette burning time model. Results showed that smokers’ exposure to the smoke depends essentially on the speed at which the cigarette is smoked. An increase in human smoking intensity, resulting in a decrease in smoking time, generates an increase in smoke exposure, whatever the puff number, puff duration, puff volume and filter ventilation (open or blocked. The association of a machine smoking yield with a corresponding smoking time, and the time taken by a consumer to smoke the cigarette would provide information on the exposure to smoke constituents in a simple and effective manner.

  3. Default values for assessment of potential dermal exposure of the hands to industrial chemicals in the scope of regulatory risk assessments

    NARCIS (Netherlands)

    Marquart, H.; Warren, N.D.; Laitinen, J.; Hemmen, J.J. van

    2006-01-01

    Dermal exposure needs to be addressed in regulatory risk assessment of chemicals. The models used so far are based on very limited data. The EU project RISKOFDERM has gathered a large number of new measurements on dermal exposure to industrial chemicals in various work situations, together with

  4. Assessment of risk of potential exposures on facilities industries; Estimativa do risco de exposicao potencial em instalacoes industriais

    Energy Technology Data Exchange (ETDEWEB)

    Leocadio, Joao Carlos

    2007-03-15

    This work develops a model to evaluate potential exposures on open facilities of industrial radiography in Brazil. This model will decisively contribute to optimize operational, radiological protection and safety procedures, to prevent radiation accidents and to reduce human errors in industrial radiography. The probabilistic safety assessment (PSA) methodology was very useful to assess potential exposures. The open facilities of industrial radiography were identified as the scenario to be analyzed in what concerns the evaluation of potential exposures, due to their high accidents indices. The results of the assessment of potential exposures confirm that the industrial radiography in Brazil is a high-risk practice as classified by the IAEA. The risk of potential exposure was estimated to be 40,5 x 10{sup -2} per year in Brazil, having as main consequences injuries to the workers' hands and arms. In the world scene, the consequences are worst, leading to fatalities of people, thus emphasizing the high risk of industrial radiography. (author)

  5. The EPA's human exposure research program for assessing cumulative risk in communities.

    Science.gov (United States)

    Zartarian, Valerie G; Schultz, Bradley D

    2010-06-01

    Communities are faced with challenges in identifying and prioritizing environmental issues, taking actions to reduce their exposures, and determining their effectiveness for reducing human health risks. Additional challenges include determining what scientific tools are available and most relevant, and understanding how to use those tools; given these barriers, community groups tend to rely more on risk perception than science. The U.S. Environmental Protection Agency's Office of Research and Development, National Exposure Research Laboratory (NERL) and collaborators are developing and applying tools (models, data, methods) for enhancing cumulative risk assessments. The NERL's "Cumulative Communities Research Program" focuses on key science questions: (1) How to systematically identify and prioritize key chemical stressors within a given community?; (2) How to develop estimates of exposure to multiple stressors for individuals in epidemiologic studies?; and (3) What tools can be used to assess community-level distributions of exposures for the development and evaluation of the effectiveness of risk reduction strategies? This paper provides community partners and scientific researchers with an understanding of the NERL research program and other efforts to address cumulative community risks; and key research needs and opportunities. Some initial findings include the following: (1) Many useful tools exist for components of risk assessment, but need to be developed collaboratively with end users and made more comprehensive and user-friendly for practical application; (2) Tools for quantifying cumulative risks and impact of community risk reduction activities are also needed; (3) More data are needed to assess community- and individual-level exposures, and to link exposure-related information with health effects; and (4) Additional research is needed to incorporate risk-modifying factors ("non-chemical stressors") into cumulative risk assessments. The products of this

  6. Radiation exposure modeling and project schedule visualization

    International Nuclear Information System (INIS)

    Jaquish, W.R.; Enderlin, V.R.

    1995-10-01

    This paper discusses two applications using IGRIP (Interactive Graphical Robot Instruction Program) to assist environmental remediation efforts at the Department of Energy (DOE) Hanford Site. In the first application, IGRIP is used to calculate the estimated radiation exposure to workers conducting tasks in radiation environments. In the second, IGRIP is used as a configuration management tool to detect interferences between equipment and personnel work areas for multiple projects occurring simultaneously in one area. Both of these applications have the capability to reduce environmental remediation costs by reducing personnel radiation exposure and by providing a method to effectively manage multiple projects in a single facility

  7. A dermatotoxicokinetic model of human exposures to jet fuel.

    Science.gov (United States)

    Kim, David; Andersen, Melvin E; Nylander-French, Leena A

    2006-09-01

    Workers, both in the military and the commercial airline industry, are exposed to jet fuel by inhalation and dermal contact. We present a dermatotoxicokinetic (DTK) model that quantifies the absorption, distribution, and elimination of aromatic and aliphatic components of jet fuel following dermal exposures in humans. Kinetic data were obtained from 10 healthy volunteers following a single dose of JP-8 to the forearm over a surface area of 20 cm2. Blood samples were taken before exposure (t = 0 h), after exposure (t = 0.5 h), and every 0.5 h for up to 3.5 h postexposure. The DTK model that best fit the data included five compartments: (1) surface, (2) stratum corneum (SC), (3) viable epidermis, (4) blood, and (5) storage. The DTK model was used to predict blood concentrations of the components of JP-8 based on dermal-exposure measurements made in occupational-exposure settings in order to better understand the toxicokinetic behavior of these compounds. Monte Carlo simulations of dermal exposure and cumulative internal dose demonstrated no overlap among the low-, medium-, and high-exposure groups. The DTK model provides a quantitative understanding of the relationship between the mass of JP-8 components in the SC and the concentrations of each component in the systemic circulation. The model may be used for the development of a toxicokinetic modeling strategy for multiroute exposure to jet fuel.

  8. A hybrid modeling with data assimilation to evaluate human exposure level

    Science.gov (United States)

    Koo, Y. S.; Cheong, H. K.; Choi, D.; Kim, A. L.; Yun, H. Y.

    2015-12-01

    Exposure models are designed to better represent human contact with PM (Particulate Matter) and other air pollutants such as CO, SO2, O3, and NO2. The exposure concentrations of the air pollutants to human are determined by global and regional long range transport of global and regional scales from Europe and China as well as local emissions from urban and road vehicle sources. To assess the exposure level in detail, the multiple scale influence from background to local sources should be considered. A hybrid air quality modeling methodology combing a grid-based chemical transport model with a local plume dispersion model was used to provide spatially and temporally resolved air quality concentration for human exposure levels in Korea. In the hybrid modeling approach, concentrations from a grid-based chemical transport model and a local plume dispersion model are added to provide contributions from photochemical interactions, long-range (regional) transport and local-scale dispersion. The CAMx (Comprehensive Air quality Model with Extensions was used for the background concentrations from anthropogenic and natural emissions in East Asia including Korea while the road dispersion by vehicle emission was calculated by CALPUFF model. The total exposure level of the pollutants was finally assessed by summing the background and road contributions. In the hybrid modeling, the data assimilation method based on the optimal interpolation was applied to overcome the discrepancies between the model predicted concentrations and observations. The air quality data from the air quality monitoring stations in Korea. The spatial resolution of the hybrid model was 50m for the Seoul Metropolitan Ares. This example clearly demonstrates that the exposure level could be estimated to the fine scale for the exposure assessment by using the hybrid modeling approach with data assimilation.

  9. Assessment of exposure to shiftwork mechanisms in the general population: the development of a new job-exposure matrix.

    Science.gov (United States)

    Fernandez, Renae C; Peters, Susan; Carey, Renee N; Davies, Michael J; Fritschi, Lin

    2014-10-01

    To develop a job-exposure matrix (JEM) that estimates exposure to eight variables representing different aspects of shiftwork among female workers. Occupational history and shiftwork exposure data were obtained from a population-based breast cancer case-control study. Exposure to light at night, phase shift, sleep disturbances, poor diet, lack of physical activity, lack of vitamin D, and graveyard and early morning shifts, was calculated by occupational code. Three threshold values based on the frequency of exposure were considered (10%, 30% and 50%) for use as cut-offs in determining exposure for each occupational code. JEM-based exposure classification was compared with that from the OccIDEAS application (job-specific questionnaires and assessment by rules) by assessing the effect on the OR for phase shift and breast cancer. Using data from the Australian Workplace Exposure Study, the specificity and sensitivity of the threshold values were calculated for each exposure variable. 127 of 413 occupational codes involved exposure to one or more shiftwork variables. Occupations with the highest probability of exposure shiftwork included nurses and midwives. Using the 30% threshold, the OR for the association between phase shift exposure and breast cancer was decreased and no longer statistically significant (OR=1.14, 95% CI 0.92 to 1.42). The 30% cut-off point demonstrated best specificity and sensitivity, although results varied between exposure variables. This JEM provides a set of indicators reflecting biologically plausible mechanisms for the potential impact of shiftwork on health and may provide an alternative method of exposure assessment in the absence of detailed job history and exposure data. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  10. Probabilistic mercury multimedia exposure assessment in small children and risk assessment.

    Science.gov (United States)

    Morisset, Typhaine; Ramirez-Martinez, Alejandra; Wesolek, Nathalie; Roudot, Alain-Claude

    2013-09-01

    Emissions of mercury in the environment have been decreasing for several years. However, mercury species are still found in different media (food, water, air and breast-milk). Due to mercury toxicity and typical behaviour in children, we have conducted a mercury exposure assessment in French babies, and small children aged 0 to 36months. Consumption and mercury concentration data were chosen for the exposure assessment. The Monte Carlo technique has been used to calculate the weekly exposure dose in order to integrate inter-individual variability and parameter uncertainty. Exposure values have been compared to toxicological reference values for health risk assessment. Inorganic mercury median exposure levels ranged from 0.160 to 1.649μg/kg of body weight per week (95th percentile (P95): 0.298-2.027µg/kg bw/week); elemental mercury median exposure level in children was 0.11ng/kg bw/week (P95: 28ng/kg bw/week); and methylmercury median exposure level ranged from 0.247 to 0.273µg/kg bw/week (P95: 0.425-0.463µg/kg bw/week). Only elemental mercury by inhalation route (indoor air) and methylmercury by ingestion (fish and breast-milk) seem to lead to a health risk in small children. These results confirm the importance of assessing total mercury concentration in media like breast-milk, indoor air and dust and methylmercury level in food, other than fish and seafood. In this way, informed monitoring plan and risk assessment in an at-risk sub-population can be set. © 2013 Elsevier Ltd. All rights reserved.

  11. Exposure Scenarios and Unit Dose Factors for the Hanford Immobilized Low Activity Tank Waste Performance Assessment

    Energy Technology Data Exchange (ETDEWEB)

    RITTMANN, P.D.

    1999-12-29

    Exposure scenarios are defined to identify potential pathways and combinations of pathways that could lead to radiation exposure from immobilized tank waste. Appropriate data and models are selected to permit calculation of dose factors for each exposure

  12. Use of ecological exposure units in ecological risk assessment

    International Nuclear Information System (INIS)

    Ferenbaugh, R.; Myers, O.; Gallegos, A.; Breshears, D.; Ebinger, M.

    1995-01-01

    The traditional approach to ecological risk assessment at hazardous waste sites that are being evaluated for cleanup under CERCLA or RCRA requirements is to focus on the immediate impacts at or adjacent to a site. While this may be acceptable in some situations, it is not ecologically defensible in situations where there are numerous contaminated sites in proximity to each other. In the latter case, transport from the sites, potential cumulative effects, and wide-ranging receptors must be considered. The concept of the Ecological Exposure Unit (EEU) has been proposed to address this situation. Ecological Exposure Units are defined on the basis of ecological considerations and each EEU may contain several to many contaminated sites. The initial steps involved in performing ecological risk assessments using the EEU approach include (1) selection of appropriate receptors and assessment endpoints, and (2) geographical definition of EEUs. At Los Alamos National Laboratory, receptors have been identified and EEUs have been defined for these receptors. GIS is being used as a tool to map EEUs. Receptors include representatives from threatened or endangered species, species reflecting status of ecological health, species with social or cultural relevance, and other species of concern. After definition of EEUs, cumulative impacts of all stressors at all sites within each EEU must be evaluated. The two major advantages to performing ecological risk assessments using this approach are that risk assessments are performed in a more scientifically defensible manner because they are performed on ecologically defined units and that resources are used optimally by minimizing redundant remedial activities

  13. Exposure assessment of workers in printed electronics workplace.

    Science.gov (United States)

    Lee, Ji Hyun; Sohn, Eun Kyung; Ahn, Jin Soo; Ahn, Kangho; Kim, Keun Soo; Lee, Jong Hwan; Lee, Taik Min; Yu, Il Je

    2013-07-01

    Printed electronics uses converging technologies, such as printing, fine mechanics, nanotechnology, electronics and other new technologies. Consequently, printed electronics raises additional health and safety concerns to those experienced in the traditional printing industry. This study investigated two printed electronics workplaces based on a walk-through survey and personal and area sampling. All the printed electronics operations were conducted in a cleanroom. No indication of exposure to excess silver nanoparticles or carbon nanotubes (CNTs) was found. While the organic solvents were lower than current occupational exposure limits, there was a lack of engineering controls, such as local exhaust ventilation, correct enclosure and duct connections. There was also an insufficient quantity of personal protective equipment, and some organic solvents not described in the safety data sheets (SDSs) were detected in the air samples. Plus, the cleaning work, a major emissions operation, was not conducted within a hood, and the cleaning waste was not properly disposed of. Therefore, the present exposure assessment results from two printed electronics workplaces suggest that the printed electronics industry needs to take note of the occupational safety and health risks and hazards already established by the traditional printing industry, along with new risks and hazards originating from converging technologies such as nanotechnology.

  14. Assessment of complex microwaves occupational exposure in radar maintenance activity

    International Nuclear Information System (INIS)

    Danulescu, R.

    1996-01-01

    The modern of the society teas determined the increase of thousand times greater than the natural fond of the humankind exposure to a complex combination of electromagnetic man-made fields and radiations of extremely various strength and frequencies. A special contribution to this environmental change has had in the last decade the appearance and the explosive development of the microwaves generating appliances such as radars used in a great variety of military and civilian applications and which essentially contributes to the electromagnetic pollution. In the above mentioned content which firstly interests the occupational environment, it is necessary to improve the exposure limits, as well as, the emission standards, in order to better protect the human health and well-being. From this point of view, the estimation of the microwave occupational exposure risk constitutes, alongside the health status assessment, one of the priorities of the Occupational Health because the theoretical and practical problems related to the bioeffects of this kind of radiations are far to be clarified. Our study has been carried out in a factory where one performs research, production and especially maintenance of microwaves generating devices. (author)

  15. Major national human biomonitoring programs in chemical exposure assessment

    Directory of Open Access Journals (Sweden)

    Judy Choi

    2015-07-01

    Full Text Available Human biomonitoring (HBM programs have been established in several countries around the world in order to monitor the levels of chemical exposures in the general population and qualify health risk assessment of national and international interest. Study design, population, sample collection, and chemical analysis must be considered when comparing and interpreting the results. In this review, the objectives and brief descriptions of the major national HBM programs in North America, Europe, and Asia are provided. Similarities and differences observed from a comparative analysis among these programs, including the stratification of data according to age, sex, socioeconomic background, etc. as well as the identification of chemical exposure associated with food intake, are discussed. Overall, although there are some discrepancies in the study designs among the reviewed national HBM programs, results from the programs can provide useful information such as chemical levels found within the general population of a country that can be compared. Furthermore, the results can be used by regulatory authorities or the government to enforce legislations in order to reduce the exposure of chemicals into the human body.

  16. Exposure assessment of a cyclist to particles and chemical elements.

    Science.gov (United States)

    Ramos, C A; Silva, J R; Faria, T; Wolterbeek, T H; Almeida, S M

    2017-05-01

    Cycle paths can be used as a route for active transportation or simply to cycle for physical activity and leisure. However, exposure to air pollutants can be boosted while cycling, in urban environments, due to the proximity to vehicular emissions and elevated breathing rates. The objective of this work was to assess the exposure of a cyclist to particles and to chemical elements by combining real-time aerosol mass concentration reading equipment and biomonitoring techniques. PM 10 and PM 2.5 were measured on three cycle paths located in Lisbon, during weekdays and weekends and during rush hours and off-peak hours resulting in a total of 60 campaigns. Lichens were exposed along cycle paths for 3 months, and their element contents were measured by instrumental neutron activation analysis using the k 0 methodology (k 0 -INAA). Using a bicycle commute route of lower traffic intensity and avoiding rush hours or other times with elevated vehicular congestion facilitate a reduction in exposure to pollutants. The implementation of cycle paths in cities is important to stimulate physical activity and active transportation; however, it is essential to consider ambient air and pollutant sources to create safer infrastructures.

  17. Mercury contamination and exposure assessment of fishery products in Korea.

    Science.gov (United States)

    Yang, Hye-Ran; Kim, Na-Young; Hwang, Lae-Hong; Park, Ju-Sung; Kim, Jung-Hun

    2015-01-01

    In this study, total (T-Hg) and methyl mercury (Me-Hg) contamination was investigated in fishery products including canned fish, fish sauces, dried bonito and frozen tuna sashimi, collected from retail markets in Korea, to assess dietary exposure. Direct mercury analyser and gas chromatography-electron captured detector were employed to measure T-Hg and Me-Hg, respectively. The highest T-Hg and Me-Hg contamination was present in tuna sashimi, followed by dried bonito, respectively. Canned tuna showed more frequent detection and higher content than other canned fishery products. The weekly exposure estimate indicates that exposure to mercury from fishery products is safe, showing 2.59% provisional tolerable weekly intake (PTWI) for T-Hg, 1.82% PTWI for Me-Hg and 4.16% reference dose for Me-Hg. However, it should be addressed to monitor the mercury contamination in fish and fishery products regularly, to safeguard vulnerable population such as children, to limit intake of these food products.

  18. Modeling Of In-Vehicle Human Exposure to Ambient Fine Particulate Matter

    Science.gov (United States)

    Liu, Xiaozhen; Frey, H. Christopher

    2012-01-01

    A method for estimating in-vehicle PM2.5 exposure as part of a scenario-based population simulation model is developed and assessed. In existing models, such as the Stochastic Exposure and Dose Simulation model for Particulate Matter (SHEDS-PM), in-vehicle exposure is estimated using linear regression based on area-wide ambient PM2.5 concentration. An alternative modeling approach is explored based on estimation of near-road PM2.5 concentration and an in-vehicle mass balance. Near-road PM2.5 concentration is estimated using a dispersion model and fixed site monitor (FSM) data. In-vehicle concentration is estimated based on air exchange rate and filter efficiency. In-vehicle concentration varies with road type, traffic flow, windspeed, stability class, and ventilation. Average in-vehicle exposure is estimated to contribute 10 to 20 percent of average daily exposure. The contribution of in-vehicle exposure to total daily exposure can be higher for some individuals. Recommendations are made for updating exposure models and implementation of the alternative approach. PMID:23101000

  19. An assessment of the acute dietary exposure to glyphosate using deterministic and probabilistic methods.

    Science.gov (United States)

    Stephenson, C L; Harris, C A; Clarke, R

    2018-02-01

    Use of glyphosate in crop production can lead to residues of the active substance and related metabolites in food. Glyphosate has never been considered acutely toxic; however, in 2015 the European Food Safety Authority (EFSA) proposed an acute reference dose (ARfD). This differs from the Joint FAO/WHO Meeting on Pesticide Residues (JMPR) who in 2016, in line with their existing position, concluded that an ARfD was not necessary for glyphosate. This paper makes a comprehensive assessment of short-term dietary exposure to glyphosate from potentially treated crops grown in the EU and imported third-country food sources. European Union and global deterministic models were used to make estimates of short-term dietary exposure (generally defined as up to 24 h). Estimates were refined using food-processing information, residues monitoring data, national dietary exposure models, and basic probabilistic approaches to estimating dietary exposure. Calculated exposures levels were compared to the ARfD, considered to be the amount of a substance that can be consumed in a single meal, or 24-h period, without appreciable health risk. Acute dietary intakes were Probabilistic exposure estimates showed that the acute intake on no person-days exceeded 10% of the ARfD, even for the pessimistic scenario.

  20. Improving the relevance and efficiency of human exposure assessments within the process of regulatory risk assessment.

    Science.gov (United States)

    Money, Chris

    2018-01-24

    The process for undertaking exposure assessments varies dependent on its purpose. But for exposure assessments to be relevant and accurate, they are reliant on access to reliable information on key exposure determinants. Acquiring such information is seldom straightforward and can take significant time and resources. This articles examines how the application of tiered and targeted approaches to information acquisition, within the context of European human health risk assessments, can not only lead to improvements in the efficiency and effectiveness of the process but also in the confidence of stakeholders in its outputs. The article explores how the benefits might be further improved through the coordination of such activities, as well as those areas that represent barriers to wider international harmonisation.

  1. A tiered asthma hazard characterization and exposure assessment approach for evaluation of consumer product ingredients.

    Science.gov (United States)

    Maier, Andrew; Vincent, Melissa J; Parker, Ann; Gadagbui, Bernard K; Jayjock, Michael

    2015-12-01

    Asthma is a complex syndrome with significant consequences for those affected. The number of individuals affected is growing, although the reasons for the increase are uncertain. Ensuring the effective management of potential exposures follows from substantial evidence that exposure to some chemicals can increase the likelihood of asthma responses. We have developed a safety assessment approach tailored to the screening of asthma risks from residential consumer product ingredients as a proactive risk management tool. Several key features of the proposed approach advance the assessment resources often used for asthma issues. First, a quantitative health benchmark for asthma or related endpoints (irritation and sensitization) is provided that extends qualitative hazard classification methods. Second, a parallel structure is employed to include dose-response methods for asthma endpoints and methods for scenario specific exposure estimation. The two parallel tracks are integrated in a risk characterization step. Third, a tiered assessment structure is provided to accommodate different amounts of data for both the dose-response assessment (i.e., use of existing benchmarks, hazard banding, or the threshold of toxicological concern) and exposure estimation (i.e., use of empirical data, model estimates, or exposure categories). Tools building from traditional methods and resources have been adapted to address specific issues pertinent to asthma toxicology (e.g., mode-of-action and dose-response features) and the nature of residential consumer product use scenarios (e.g., product use patterns and exposure durations). A case study for acetic acid as used in various sentinel products and residential cleaning scenarios was developed to test the safety assessment methodology. In particular, the results were used to refine and verify relationships among tiered approaches such that each lower data tier in the approach provides a similar or greater margin of safety for a given

  2. Simulation of Population-Based Commuter Exposure to NO2 Using Different Air Pollution Models

    Directory of Open Access Journals (Sweden)

    Martina S. Ragettli

    2014-05-01

    Full Text Available We simulated commuter routes and long-term exposure to traffic-related air pollution during commute in a representative population sample in Basel (Switzerland, and evaluated three air pollution models with different spatial resolution for estimating commute exposures to nitrogen dioxide (NO2 as a marker of long-term exposure to traffic-related air pollution. Our approach includes spatially and temporally resolved data on actual commuter routes, travel modes and three air pollution models. Annual mean NO2 commuter exposures were similar between models. However, we found more within-city and within-subject variability in annual mean (±SD NO2 commuter exposure with a high resolution dispersion model (40 ± 7 µg m−3, range: 21–61 than with a dispersion model with a lower resolution (39 ± 5 µg m−3; range: 24–51, and a land use regression model (41 ± 5 µg m−3; range: 24–54. Highest median cumulative exposures were calculated along motorized transport and bicycle routes, and the lowest for walking. For estimating commuter exposure within a city and being interested also in small-scale variability between roads, a model with a high resolution is recommended. For larger scale epidemiological health assessment studies, models with a coarser spatial resolution are likely sufficient, especially when study areas include suburban and rural areas.

  3. Monitor for detecting and assessing exposure to airborne nanoparticles

    International Nuclear Information System (INIS)

    Marra, Johan; Voetz, Matthias; Kiesling, Heinz-Juergen

    2010-01-01

    An important safety aspect of the workplace environment concerns the severity of its air pollution with nanoparticles (NP; <100 nm) and ultrafine particles (UFP; <300 nm). Depending on their size and chemical nature, exposure to these particles through inhalation can be hazardous because of their intrinsic ability to deposit in the deep lung regions and the possibility to subsequently pass into the blood stream. Recommended safety measures in the nanomaterials industry are pragmatic, aiming at exposure minimization in general, and advocating continuous control by monitoring both the workplace air pollution level and the personal exposure to airborne NPs. This article describes the design and operation of the Aerasense NP monitor that enables intelligence gathering in particular with respect to airborne particles in the 10-300 nm size range. The NP monitor provides real time information about their number concentration, average size, and surface areas per unit volume of inhaled air that deposit in the various compartments of the respiratory tract. The monitor's functionality relies on electrical charging of airborne particles and subsequent measurements of the total particle charge concentration under various conditions. Information obtained with the NP monitor in a typical workplace environment has been compared with simultaneously recorded data from a Scanning Mobility Particle Sizer (SMPS) capable of measuring the particle size distribution in the 11-1086 nm size range. When the toxicological properties of the engineered and/or released particles in the workplace are known, personal exposure monitoring allows a risk assessment to be made for a worker during each workday, when the workplace-produced particles can be distinguished from other (ambient) particles.

  4. Examining Exposure Assessment in Shift Work Research: A Study on Depression Among Nurses.

    Science.gov (United States)

    Hall, Amy L; Franche, Renée-Louise; Koehoorn, Mieke

    2018-02-13

    Coarse exposure assessment and assignment is a common issue facing epidemiological studies of shift work. Such measures ignore a number of exposure characteristics that may impact on health, increasing the likelihood of biased effect estimates and masked exposure-response relationships. To demonstrate the impacts of exposure assessment precision in shift work research, this study investigated relationships between work schedule and depression in a large survey of Canadian nurses. The Canadian 2005 N