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Sample records for accurate exposure assessment

  1. Exposure assessment of trichloroethylene.

    PubMed

    Wu, C; Schaum, J

    2000-05-01

    This article reviews exposure information available for trichloroethylene (TCE) and assesses the magnitude of human exposure. The primary sources releasing TCE into the environment are metal cleaning and degreasing operations. Releases occur into all media but mostly into the air due to its volatility. It is also moderately soluble in water and can leach from soils into groundwater. TCE has commonly been found in ambient air, surface water, and groundwaters. The 1998 air levels in microg/m(3) across 115 monitors can be summarized as follows: range = 0.01-3.9, mean = 0.88. A California survey of large water utilities in 1984 found a median concentration of 3.0 microg/L. General population exposure to TCE occurs primarily by inhalation and water ingestion. Typical average daily intakes have been estimated as 11-33 microg/day for inhalation and 2-20 microg/day for ingestion. A small portion of the population is expected to have elevated exposures as a result of one or more of these pathways: inhalation exposures to workers involved in degreasing operations, ingestion and inhalation exposures occurring in homes with private wells located near disposal/contamination sites, and inhalation exposures to consumers using TCE products in areas of poor ventilation. More current and more extensive data on TCE levels in indoor air, water, and soil are needed to better characterize the distribution of background exposures in the general population and elevated exposures in special subpopulations.

  2. Exposure assessment of trichloroethylene.

    PubMed Central

    Wu, C; Schaum, J

    2000-01-01

    This article reviews exposure information available for trichloroethylene (TCE) and assesses the magnitude of human exposure. The primary sources releasing TCE into the environment are metal cleaning and degreasing operations. Releases occur into all media but mostly into the air due to its volatility. It is also moderately soluble in water and can leach from soils into groundwater. TCE has commonly been found in ambient air, surface water, and groundwaters. The 1998 air levels in microg/m(3) across 115 monitors can be summarized as follows: range = 0.01-3.9, mean = 0.88. A California survey of large water utilities in 1984 found a median concentration of 3.0 microg/L. General population exposure to TCE occurs primarily by inhalation and water ingestion. Typical average daily intakes have been estimated as 11-33 microg/day for inhalation and 2-20 microg/day for ingestion. A small portion of the population is expected to have elevated exposures as a result of one or more of these pathways: inhalation exposures to workers involved in degreasing operations, ingestion and inhalation exposures occurring in homes with private wells located near disposal/contamination sites, and inhalation exposures to consumers using TCE products in areas of poor ventilation. More current and more extensive data on TCE levels in indoor air, water, and soil are needed to better characterize the distribution of background exposures in the general population and elevated exposures in special subpopulations. Images Figure 1 PMID:10807565

  3. Asbestos Exposure Assessment Database

    NASA Technical Reports Server (NTRS)

    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.

  4. EPIDEMIOLOGY AND EXPOSURE ASSESSMENT

    EPA Science Inventory

    Research collaborations between the National Health and Environmental Effects Research Laboratory (NHEERL) and the National Exposure Research Laboratory (NERL) centered on the development and application of exposure analysis tools in environmental epidemiology include the El Paso...

  5. Does more accurate exposure prediction necessarily improve health effect estimates?

    PubMed

    Szpiro, Adam A; Paciorek, Christopher J; Sheppard, Lianne

    2011-09-01

    A unique challenge in air pollution cohort studies and similar applications in environmental epidemiology is that exposure is not measured directly at subjects' locations. Instead, pollution data from monitoring stations at some distance from the study subjects are used to predict exposures, and these predicted exposures are used to estimate the health effect parameter of interest. It is usually assumed that minimizing the error in predicting the true exposure will improve health effect estimation. We show in a simulation study that this is not always the case. We interpret our results in light of recently developed statistical theory for measurement error, and we discuss implications for the design and analysis of epidemiologic research.

  6. HUMAN EXPOSURE ASSESSMENT USING IMMUNOASSAY

    EPA Science Inventory

    The National Exposure Research Laboratory-Las Vegas is developing analytical methods for human exposure assessment studies. Critical exposure studies generate a large number of samples which must be analyzed in a reliable, cost-effective and timely manner. TCP (3,5,6-trichlor...

  7. Change in BMI accurately predicted by social exposure to acquaintances.

    PubMed

    Oloritun, Rahman O; Ouarda, Taha B M J; Moturu, Sai; Madan, Anmol; Pentland, Alex Sandy; Khayal, Inas

    2013-01-01

    Research has mostly focused on obesity and not on processes of BMI change more generally, although these may be key factors that lead to obesity. Studies have suggested that obesity is affected by social ties. However these studies used survey based data collection techniques that may be biased toward select only close friends and relatives. In this study, mobile phone sensing techniques were used to routinely capture social interaction data in an undergraduate dorm. By automating the capture of social interaction data, the limitations of self-reported social exposure data are avoided. This study attempts to understand and develop a model that best describes the change in BMI using social interaction data. We evaluated a cohort of 42 college students in a co-located university dorm, automatically captured via mobile phones and survey based health-related information. We determined the most predictive variables for change in BMI using the least absolute shrinkage and selection operator (LASSO) method. The selected variables, with gender, healthy diet category, and ability to manage stress, were used to build multiple linear regression models that estimate the effect of exposure and individual factors on change in BMI. We identified the best model using Akaike Information Criterion (AIC) and R(2). This study found a model that explains 68% (p<0.0001) of the variation in change in BMI. The model combined social interaction data, especially from acquaintances, and personal health-related information to explain change in BMI. This is the first study taking into account both interactions with different levels of social interaction and personal health-related information. Social interactions with acquaintances accounted for more than half the variation in change in BMI. This suggests the importance of not only individual health information but also the significance of social interactions with people we are exposed to, even people we may not consider as close friends.

  8. Accurate measurement of RF exposure from emerging wireless communication systems

    NASA Astrophysics Data System (ADS)

    Letertre, Thierry; Monebhurrun, Vikass; Toffano, Zeno

    2013-04-01

    Isotropic broadband probes or spectrum analyzers (SAs) may be used for the measurement of rapidly varying electromagnetic fields generated by emerging wireless communication systems. In this paper this problematic is investigated by comparing the responses measured by two different isotropic broadband probes typically used to perform electric field (E-field) evaluations. The broadband probes are submitted to signals with variable duty cycles (DC) and crest factors (CF) either with or without Orthogonal Frequency Division Multiplexing (OFDM) modulation but with the same root-mean-square (RMS) power. The two probes do not provide accurate enough results for deterministic signals such as Worldwide Interoperability for Microwave Access (WIMAX) or Long Term Evolution (LTE) as well as for non-deterministic signals such as Wireless Fidelity (WiFi). The legacy measurement protocols should be adapted to cope for the emerging wireless communication technologies based on the OFDM modulation scheme. This is not easily achieved except when the statistics of the RF emission are well known. In this case the measurement errors are shown to be systematic and a correction factor or calibration can be applied to obtain a good approximation of the total RMS power.

  9. What's Normal? Accurately and Efficiently Assessing Menstrual Function.

    PubMed

    Takemoto, Darcie M; Beharry, Meera S

    2015-09-01

    Many young women are unsure of what constitutes normal menses. By asking focused questions, pediatric providers can quickly and accurately assess menstrual function and dispel anxiety and myths. In this article, we review signs and symptoms of normal versus pathologic menstrual functioning and provide suggestions to improve menstrual history taking.

  10. Personal Exposure Monitoring Wearing Protocol Compliance: An Initial Assessment of Quantitative Measurements

    EPA Science Inventory

    Personal exposure sampling provides the most accurate and representative assessment of exposure to a pollutant, but only if measures are implemented to minimize exposure misclassification and reduce confounders that may cause misinterpretation of the collected data. Poor complian...

  11. Environmental tobacco smoke exposure assessment

    SciTech Connect

    Guerin, M.R.

    1993-06-01

    Environmental tobacco smoke (ETS) is the material released into the environment as tobacco products are smoked. Cigarettes, pipes, and cigars all produce ETS but the term has become all but synonymous with indoor air contamination by cigarette smoking. This is because cigarettes are by far the most commonly consumed tobacco product and because the principal human exposure occurs indoors. Exposure to ETS is variously termed as passive smoking, involuntary smoking, and as exposure to second-hand smoke. Considerable progress has been made toward a better understanding of ETS exposure. Strengths and limitations of various measures of exposure are better understood and much data has been generated on the quantities of many ETS-constituents in many indoor environments. The properties of ETS, methods for its measurement in indoor air, and many results of field studies have recently been reviewed by the author. The recent EPA report includes a major treatment of exposure estimation including air concentrations, questionnaires, and biomarkers. This paper discusses approaches to exposure assessment and summarizes data on indoor air concentrations of ETS-constituents.

  12. Environmental tobacco smoke exposure assessment

    SciTech Connect

    Guerin, M.R.

    1993-01-01

    Environmental tobacco smoke (ETS) is the material released into the environment as tobacco products are smoked. Cigarettes, pipes, and cigars all produce ETS but the term has become all but synonymous with indoor air contamination by cigarette smoking. This is because cigarettes are by far the most commonly consumed tobacco product and because the principal human exposure occurs indoors. Exposure to ETS is variously termed as passive smoking, involuntary smoking, and as exposure to second-hand smoke. Considerable progress has been made toward a better understanding of ETS exposure. Strengths and limitations of various measures of exposure are better understood and much data has been generated on the quantities of many ETS-constituents in many indoor environments. The properties of ETS, methods for its measurement in indoor air, and many results of field studies have recently been reviewed by the author. The recent EPA report includes a major treatment of exposure estimation including air concentrations, questionnaires, and biomarkers. This paper discusses approaches to exposure assessment and summarizes data on indoor air concentrations of ETS-constituents.

  13. INDOOR AEROSOLS AND EXPOSURE ASSESSMENT

    EPA Science Inventory

    This chapter provides an overview of both indoor aerosol concentration measurements, and the considerations for assessment of exposure to aerosols in non-occupational settings. The fixed-location measurements of concentration at an outdoor location, while commuting inside an a...

  14. Can blind persons accurately assess body size from the voice?

    PubMed

    Pisanski, Katarzyna; Oleszkiewicz, Anna; Sorokowska, Agnieszka

    2016-04-01

    Vocal tract resonances provide reliable information about a speaker's body size that human listeners use for biosocial judgements as well as speech recognition. Although humans can accurately assess men's relative body size from the voice alone, how this ability is acquired remains unknown. In this study, we test the prediction that accurate voice-based size estimation is possible without prior audiovisual experience linking low frequencies to large bodies. Ninety-one healthy congenitally or early blind, late blind and sighted adults (aged 20-65) participated in the study. On the basis of vowel sounds alone, participants assessed the relative body sizes of male pairs of varying heights. Accuracy of voice-based body size assessments significantly exceeded chance and did not differ among participants who were sighted, or congenitally blind or who had lost their sight later in life. Accuracy increased significantly with relative differences in physical height between men, suggesting that both blind and sighted participants used reliable vocal cues to size (i.e. vocal tract resonances). Our findings demonstrate that prior visual experience is not necessary for accurate body size estimation. This capacity, integral to both nonverbal communication and speech perception, may be present at birth or may generalize from broader cross-modal correspondences. PMID:27095264

  15. Accurate assessment and identification of naturally occurring cellular cobalamins

    PubMed Central

    Hannibal, Luciana; Axhemi, Armend; Glushchenko, Alla V.; Moreira, Edward S.; Brasch, Nicola E.; Jacobsen, Donald W.

    2009-01-01

    Background Accurate assessment of cobalamin profiles in human serum, cells, and tissues may have clinical diagnostic value. However, non-alkyl forms of cobalamin undergo β-axial ligand exchange reactions during extraction, which leads to inaccurate profiles having little or no diagnostic value. Methods Experiments were designed to: 1) assess β-axial ligand exchange chemistry during the extraction and isolation of cobalamins from cultured bovine aortic endothelial cells, human foreskin fibroblasts, and human hepatoma HepG2 cells, and 2) to establish extraction conditions that would provide a more accurate assessment of endogenous forms containing both exchangeable and non-exchangeable β-axial ligands. Results The cobalamin profile of cells grown in the presence of [57Co]-cyanocobalamin as a source of vitamin B12 shows that the following derivatives are present: [57Co]-aquacobalamin, [57Co]-glutathionylcobalamin, [57Co]-sulfitocobalamin, [57Co]-cyanocobalamin, [57Co]-adenosylcobalamin, [57Co]-methylcobalamin, as well as other yet unidentified corrinoids. When the extraction is performed in the presence of excess cold aquacobalamin acting as a scavenger cobalamin (i.e., “cold trapping”), the recovery of both [57Co]-glutathionylcobalamin and [57Co]-sulfitocobalamin decreases to low but consistent levels. In contrast, the [57Co]-nitrocobalamin observed in extracts prepared without excess aquacobalamin is undetectable in extracts prepared with cold trapping. Conclusions This demonstrates that β-ligand exchange occurs with non-covalently bound β-ligands. The exception to this observation is cyanocobalamin with a non-covalent but non-exchangeable− CNT group. It is now possible to obtain accurate profiles of cellular cobalamins. PMID:18973458

  16. Novel serologic biomarkers provide accurate estimates of recent Plasmodium falciparum exposure for individuals and communities

    PubMed Central

    Helb, Danica A.; Tetteh, Kevin K. A.; Felgner, Philip L.; Skinner, Jeff; Hubbard, Alan; Arinaitwe, Emmanuel; Mayanja-Kizza, Harriet; Ssewanyana, Isaac; Kamya, Moses R.; Beeson, James G.; Tappero, Jordan; Smith, David L.; Crompton, Peter D.; Rosenthal, Philip J.; Dorsey, Grant; Drakeley, Christopher J.; Greenhouse, Bryan

    2015-01-01

    Tools to reliably measure Plasmodium falciparum (Pf) exposure in individuals and communities are needed to guide and evaluate malaria control interventions. Serologic assays can potentially produce precise exposure estimates at low cost; however, current approaches based on responses to a few characterized antigens are not designed to estimate exposure in individuals. Pf-specific antibody responses differ by antigen, suggesting that selection of antigens with defined kinetic profiles will improve estimates of Pf exposure. To identify novel serologic biomarkers of malaria exposure, we evaluated responses to 856 Pf antigens by protein microarray in 186 Ugandan children, for whom detailed Pf exposure data were available. Using data-adaptive statistical methods, we identified combinations of antibody responses that maximized information on an individual’s recent exposure. Responses to three novel Pf antigens accurately classified whether an individual had been infected within the last 30, 90, or 365 d (cross-validated area under the curve = 0.86–0.93), whereas responses to six antigens accurately estimated an individual’s malaria incidence in the prior year. Cross-validated incidence predictions for individuals in different communities provided accurate stratification of exposure between populations and suggest that precise estimates of community exposure can be obtained from sampling a small subset of that community. In addition, serologic incidence predictions from cross-sectional samples characterized heterogeneity within a community similarly to 1 y of continuous passive surveillance. Development of simple ELISA-based assays derived from the successful selection strategy outlined here offers the potential to generate rich epidemiologic surveillance data that will be widely accessible to malaria control programs. PMID:26216993

  17. Assessing secondhand smoke exposure with reported measures

    PubMed Central

    Elf, Jessica L; Cummings, K Michael; Fong, Geoffrey T; Hovell, Melbourne F; Klein, Jonathan D; McMillen, Robert; Winickoff, Jonathan P; Samet, Jonathan M

    2013-01-01

    Non-smokers are exposed to tobacco smoke from the burning cigarette and the exhaled smoke from smokers. In spite of decades of development of approaches to assess secondhand smoke exposure (SHSe), there are still unresolved methodological issues. This manuscript summarises the scientific evidence on the use of SHSe reported measures and their methods, objectives, strengths and limitations; and discusses best practices for assessing behaviour leading to SHSe for lifetime and immediate or current SHSe. Recommendations for advancing measurement science of SHSe are provided. Behavioural measures of SHSe commonly rely on self-reports from children and adults. Most commonly, the methodology includes self, proxy and interview-based reporting styles using retrospective recall or diary-style reporting formats. The reporting method used will vary based upon the subject of interest, assessment objectives and cultural context. Appropriately implemented, reported measures of SHSe provide an accurate, timely and cost-effective method for assessing exposure time, location and quantity in a wide variety of populations. PMID:22949496

  18. EXPOSURE ASSESSMENT AND FUTURE DIRECTIONS IN EXPOSURE SCIENCE

    EPA Science Inventory

    Exposure is the contact between a stressor and a human or ecological receptor. Risk analysis step in which receptor interaction with the exposure stressor of concern is evaluated. To assess exposure to a particular stressor we need to know - Properties of the stressor; Sources, p...

  19. Can parents of children with cancer accurately report their child's passive smoking exposure?

    PubMed Central

    Lensing, Shelly; Vukadinovich, Christopher M.; Hovell, Melbourne F.

    2009-01-01

    Introduction: This study examined whether children with cancer are exposed to measurable levels of passive smoke as assessed by parent report and laboratory measures of urine cotinine, an established biomarker of passive smoke exposure (PSE). It also determined whether parents/caretakers of young cancer patients can provide valid reports of their child's PSE during the child's treatment, by examining their association with urine cotinine measures. Methods: Participants included 124 parents of a child with cancer who lived with at least one adult smoker in the home and was exposed to tobacco smoke in the home and/or car. Eligible patients were younger than 18 years of age, were receiving active treatment for cancer at a large pediatric oncology institution, were at least 30 days postdiagnosis, and did not smoke. Parents provided information about smoking and their child's PSE by responding to a series of questionnaires. Patients provided urine samples for cotinine analyses. Results: Findings showed that parents provided valid short-term accounts of their child's PSE in the context of their child's cancer treatment. Parent reports of PSE showed moderately strong positive relationships with urine cotinine levels which were stronger for reports provided by parents who smoked compared with nonsmoking parents. Discussion: Parent reports of PSE were validated by positive and significant associations with urine cotinine. Reports provided in the context of possible verification by biomarker assays can provide sufficiently accurate estimates of PSE to serve as outcome measures for clinical research and clinical care in a pediatric cancer setting. PMID:19696308

  20. Response to “Accurate Risk-Based Chemical Screening Relies on Robust Exposure Estimates”

    EPA Science Inventory

    This is a correspondence (letter to the editor) with reference to comments by Rudel and Perovich on the article "Integration of Dosimetry, Exposure, and High-Throughput Screening Data in Chemical Toxicity Assessment". Article Reference: SI # 238882

  1. Exposure Assessment in Cohort Studies of Childhood Asthma

    PubMed Central

    Arrandale, Victoria H.; Brauer, Michael; Brook, Jeffrey R.; Brunekreef, Bert; Gold, Diane R.; London, Stephanie J.; Miller, J. David; Özkaynak, Halûk; Ries, Nola M.; Sears, Malcolm R.; Silverman, Frances S.; Takaro, Tim K.

    2011-01-01

    Background The environment is suspected to play an important role in the development of childhood asthma. Cohort studies are a powerful observational design for studying exposure–response relationships, but their power depends in part upon the accuracy of the exposure assessment. Objective The purpose of this paper is to summarize and discuss issues that make accurate exposure assessment a challenge and to suggest strategies for improving exposure assessment in longitudinal cohort studies of childhood asthma and allergies. Data synthesis Exposures of interest need to be prioritized, because a single study cannot measure all potentially relevant exposures. Hypotheses need to be based on proposed mechanisms, critical time windows for effects, prior knowledge of physical, physiologic, and immunologic development, as well as genetic pathways potentially influenced by the exposures. Modifiable exposures are most important from the public health perspective. Given the interest in evaluating gene–environment interactions, large cohort sizes are required, and planning for data pooling across independent studies is critical. Collection of additional samples, possibly through subject participation, will permit secondary analyses. Models combining air quality, environmental, and dose data provide exposure estimates across large cohorts but can still be improved. Conclusions Exposure is best characterized through a combination of information sources. Improving exposure assessment is critical for reducing measurement error and increasing power, which increase confidence in characterization of children at risk, leading to improved health outcomes. PMID:21081299

  2. Assessing human exposure to airborne pollutants: Advances and opportunities

    SciTech Connect

    Lioy, P.J. )

    1991-08-01

    A committee which was convened by the National Research Council, recently completed an analysis of new methods and technologies for assessing exposure to air pollutants. The committee identified three major ways of determining human exposure to airborne pollutants. Monitoring the air around an individual with a portable personal air sampler is, of course, the most comprehensive and most accurate. It is also the costliest and most time consuming. The second method is more indirect and involves techniques such as measuring the amount of a contaminant with a stationary monitor and extrapolating exposure by means of personal activity records or mathematical models. Exposure to carbon monoxide inside a car, for example, might be roughly calculated from the amount of time spent in the car and the quantity of carbon monoxide in the car under typical operating conditions. The third method involves biological markers as a measure of the integrated dose within the body and of past contact with pollutants. For example, a marker for airborne lead exposure can be elevated lead levels in the blood. However, this must be weighed against contributions from other media. A final and major point made in the report is the need to have accurate and realistic assessments to ensure optimal reduction of human exposure. To accomplish this, exposure assessment research should be supported by government programs. Although not stated, such research should also be supported by other sectors, including the regulated community.

  3. Developing Korean Standard for Nanomaterial Exposure Assessment

    PubMed Central

    Lee, Ji Hyun; Lee, Jun Yeob

    2011-01-01

    Nanotechnology is now applied to many industries, resulting in wide range of nanomaterial-containing products, such as electronic components, cosmetic, medicines, vehicles, and home appliances. Nanoparticles can be released throughout the life cycle of nanoproducts, including the manufacture, consumer use, and disposal, thereby involving workers, consumers, and the environment in potential exposure. However, there is no current consensus on the best sampling method for characterizing manufactured-nanoparticle exposure. Therefore, this report aims to provide a standard method for assessing nanoparticle exposure, including the identification of nanoparticle emission, the assessment of worker exposure, and the evaluation of exposure mitigation actions in nanomaterial-handling workplaces or research institutes. PMID:24278552

  4. Exposure assessment: Serum levels of TCDD in Seveso, Italy

    SciTech Connect

    Needham, L.L.; Patterson, D.G. Jr.; Smith, S.J.; Sampson, E.J.; Gerthoux, P.M.; Brambilla, P.; Mocarelli, P.

    1999-02-01

    Accurate exposure assessment is an important step in both risk assessment and epidemiologic studies involving potential human exposure to environmental toxicants. Various methods have been used to assess human exposure. These methods include models based on one`s temporal and spatial nearness to the source, environmental levels of toxicant, and biological measures. The authors believe that the latter measure is the ``gold standard.`` In this article they present the serum 2,3,7,8-tetrachlorodibenzo-p-dioxin levels in residents of the contaminated zones in Seveso, Italy, in 1976, and delineate these data by age and gender. Some of these serum levels are among the highest ever reported and thus this population serves as a benchmark for comparison of human exposure and potential adverse health effects. One such potential population is that population consuming potentially contaminated fish.

  5. Mycotoxins: occurrence, toxicology, and exposure assessment.

    PubMed

    Marin, S; Ramos, A J; Cano-Sancho, G; Sanchis, V

    2013-10-01

    Mycotoxins are abiotic hazards produced by certain fungi that can grow on a variety of crops. Consequently, their prevalence in plant raw materials may be relatively high. The concentration of mycotoxins in finished products is usually lower than in raw materials. In this review, occurrence and toxicology of the main mycotoxins are summarised. Furthermore, methodological approaches for exposure assessment are described. Existing exposure assessments, both through contamination and consumption data and biomarkers of exposure, for the main mycotoxins are also discussed.

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

    EPA Science Inventory

    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 ...

  7. Increasing Accurate Preference Assessment Implementation through Pyramidal Training

    ERIC Educational Resources Information Center

    Pence, Sacha T.; St. Peter, Claire C.; Tetreault, Allison S.

    2012-01-01

    Preference assessments directly evaluate items that may serve as reinforcers, and their implementation is an important skill for individuals who work with children. This study examined the effectiveness of pyramidal training on teachers' implementation of preference assessments. During Experiment 1, 3 special education teachers taught 6 trainees…

  8. Internal Medicine Residents Do Not Accurately Assess Their Medical Knowledge

    ERIC Educational Resources Information Center

    Jones, Roger; Panda, Mukta; Desbiens, Norman

    2008-01-01

    Background: Medical knowledge is essential for appropriate patient care; however, the accuracy of internal medicine (IM) residents' assessment of their medical knowledge is unknown. Methods: IM residents predicted their overall percentile performance 1 week (on average) before and after taking the in-training exam (ITE), an objective and well…

  9. Exposure assessment for chemical and physical agents.

    PubMed

    Moretto, Angelo

    2015-01-01

    Exposure assessment to either chemical or physical agents, as applicable, is a necessary step for both etiologic diagnosis of occupational disease and health surveillance of workers. The assessment can be carried out by measurements of concentrations in air of the substance by either fixed or personal samplers. The former give an indication of the general environment, the latter, applied near the mouth of the worker, provide personalized information. Dermal exposure (deposition) and absorption occur in the occupational setting, but their measurement is so complex that there are no routine methods and no exposure limits established. Oral exposure is accidental or associated with poor hygienic practices, is very difficult to assess, and there are no occupational exposure limits of oral intake. Also accidental injuries caused by needles or other sharp objects that might be contaminated by chemicals occur but exposure assessment in this condition is almost impossible. Exposure is also assessed by biologic monitoring that entails measurements of the substance and/or of its metabolite(s) in accessible fluids, generally urine, blood, or expired air. Biochemical changes, e.g., enzyme inhibition, associated with exposure are also measured. The results of these measurements are compared with existing limit values in order to conclude on the safety of the working conditions. Since the limit values are derived with the application of conservative assumptions, there are no fine lines between health and disease. Therefore, in the clinical setting values below the limit can be generally regarded as safe. Values above the limits should be considered in conjunction with all other information to judge on the likelihood that the disease under investigation may have been caused by exposure to the substance. PMID:26563782

  10. Exposure scenario libraries as a tool for exposure assessment

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  11. Home Circadian Phase Assessments with Measures of Compliance Yield Accurate Dim Light Melatonin Onsets

    PubMed Central

    Burgess, Helen J.; Wyatt, James K.; Park, Margaret; Fogg, Louis F.

    2015-01-01

    Study Objectives: There is a need for the accurate assessment of circadian phase outside of the clinic/laboratory, particularly with the gold standard dim light melatonin onset (DLMO). We tested a novel kit designed to assist in saliva sampling at home for later determination of the DLMO. The home kit includes objective measures of compliance to the requirements for dim light and half-hourly saliva sampling. Design: Participants were randomized to one of two 10-day protocols. Each protocol consisted of two back-to-back home and laboratory phase assessments in counterbalanced order, separated by a 5-day break. Setting: Laboratory or participants' homes. Participants: Thirty-five healthy adults, age 21–62 y. Interventions: N/A. Measurements and Results: Most participants received at least one 30-sec epoch of light > 50 lux during the home phase assessments (average light intensity 4.5 lux), but on average for < 9 min of the required 8.5 h. Most participants collected every saliva sample within 5 min of the scheduled time. Ninety-two percent of home DLMOs were not affected by light > 50 lux or sampling errors. There was no significant difference between the home and laboratory DLMOs (P > 0.05); on average the home DLMOs occurred 9.6 min before the laboratory DLMOs. The home DLMOs were highly correlated with the laboratory DLMOs (r = 0.91, P < 0.001). Conclusions: Participants were reasonably compliant to the home phase assessment procedures. The good agreement between the home and laboratory dim light melatonin onsets (DLMOs) demonstrates that including objective measures of light exposure and sample timing during home saliva sampling can lead to accurate home DLMOs. Clinical Trial Registration: Circadian Phase Assessments at Home, http://clinicaltrials.gov/show/NCT01487252, NCT01487252. Citation: Burgess HJ, Wyatt JK, Park M, Fogg LF. Home circadian phase assessments with measures of compliance yield accurate dim light melatonin onsets. SLEEP 2015;38(6):889–897

  12. Assessment of human exposure level to PM10 in China

    NASA Astrophysics Data System (ADS)

    An, Xingqin; Hou, Qing; Li, Nan; Zhai, Shixian

    2013-05-01

    Epidemiological studies have found that atmospheric particulate matter, especially PM10 (inhalable particulate matter with aerodynamic diameter less than or equal to 10 μm) is one of the pollutants that are harmful to human health. In recent years, particulate matter pollution in China is becoming increasingly serious and PM10 has become the primary pollutant in Beijing and other cities. Therefore, it is necessary to carry out studies and a health damage assessment of PM10. In human health damage assessment, measuring human exposure level to PM10 is required and crucial to provide accurate exposure data for the exposure-response relationship, and also for the accurate quantitative assessment of human exposure. The spatial distribution of particle concentration in China is variable because of spatial differences in the local economic level and the geographical environment. Along with the accelerating urbanisation in China, city population density is high, and the population distribution is variable between and within cities, thus resulting in different population numbers exposed to different concentration ranges. Therefore, an accurate assessment of China's level of exposure to particulate matter is a priority and the basis for assessing the damage to public health caused by particle pollution. Using high accuracy population and PM10 monitoring data, this study analysed the human exposure to PM10 in different regions and typical cities of China. The results show that for most areas of China, the population-weighted PM10 exposure concentration is slightly higher than the annual mean concentration, meaning that more of the population is exposed to high concentrations, and most of the population is exposed to levels that meet the second national standard (between 40 and 100 μg m-3), occupying about 83.7% of population and 76.3% of area in China. The population exposure to PM10 is higher in two types of typical regions and cities: areas with dense human populations

  13. Assessing exposures to environmental tobacco smoke

    SciTech Connect

    Leaderer, B.P. )

    1990-01-01

    The combustion of tobacco indoors results in the emission of a wide range of air contaminants that are associated with a variety of acute and chronic health and comfort effects. Exposures to environmental tobacco smoke (ETS) are assessed for epidemiologic studies and risk assessment and risk management applications. An individual's or population's exposure to ETS can be assessed by direct methods, which employ personal air monitoring and biomarkers, and indirect methods, which utilize various degrees of microenvironmental measurements of spaces, models, and questionnaires in combination with time-activity information. The major issues related to assessing exposures to ETS are summarized and discussed, including the physical-chemical nature of ETS air contaminants, use of proxy air contaminants to represent ETS, use of biomarkers, models for estimating ETS concentrations indoors, and the application of questionnaires.

  14. Children's exposure assessment: a review of factors influencing Children's exposure, and the data available to characterize and assess that exposure.

    PubMed Central

    Cohen Hubal, E A; Sheldon, L S; Burke, J M; McCurdy, T R; Berry, M R; Rigas, M L; Zartarian, V G; Freeman, N C

    2000-01-01

    We review the factors influencing children's exposure to environmental contaminants and the data available to characterize and assess that exposure. Children's activity pattern data requirements are demonstrated in the context of the algorithms used to estimate exposure by inhalation, dermal contact, and ingestion. Currently, data on children's exposures and activities are insufficient to adequately assess multimedia exposures to environmental contaminants. As a result, regulators use a series of default assumptions and exposure factors when conducting exposure assessments. Data to reduce uncertainty in the assumptions and exposure estimates are needed to ensure chemicals are regulated appropriately to protect children's health. To improve the database, advancement in the following general areas of research is required: identification of appropriate age/developmental benchmarks for categorizing children in exposure assessment; development and improvement of methods for monitoring children's exposures and activities; collection of activity pattern data for children (especially young children) required to assess exposure by all routes; collection of data on concentrations of environmental contaminants, biomarkers, and transfer coefficients that can be used as inputs to aggregate exposure models. PMID:10856019

  15. Health assessment of exposure to developmental toxicants

    SciTech Connect

    Kimmel, C.A.

    1987-07-01

    In 1984, the U.S. EPA published proposed Guidelines for the Health Assessment of Suspect Developmental Toxicants. The assessment of data from studies on developmental effects of chemical exposure and the estimation of risk for humans is a difficult process. Although structure/activity relationships and data from short-term tests are often used in the risk-assessment process for assessing carcinogens, these are not useful as the first step in developmental toxicity risk assessment. Human epidemiological data are used, if available, but often the only available evidence is from animal studies. Therefore, the guidelines focus on the evaluation of data from routine animal testing studies.

  16. Personal exposure meets risk assessment: a comparison of measured and modeled exposures and risks in an urban community.

    PubMed Central

    Payne-Sturges, Devon C; Burke, Thomas A; Breysse, Patrick; Diener-West, Marie; Buckley, Timothy J

    2004-01-01

    Human exposure research has consistently shown that, for most volatile organic compounds (VOCs), personal exposures are vastly different from outdoor air concentrations. Therefore, risk estimates based on ambient measurements may over- or underestimate risk, leading to ineffective or inefficient management strategies. In the present study we examine the extent of exposure misclassification and its impact on risk for exposure estimated by the U.S. Environmental Protection Agency (U.S. EPA) Assessment System for Population Exposure Nationwide (ASPEN) model relative to monitoring results from a community-based exposure assessment conducted in Baltimore, Maryland (USA). This study is the first direct comparison of the ASPEN model (as used by the U.S. EPA for the Cumulative Exposure Project and subsequently the National-Scale Air Toxics Assessment) and human exposure data to estimate health risks. A random sampling strategy was used to recruit 33 nonsmoking adult community residents. Passive air sampling badges were used to assess 3-day time-weighted-average personal exposure as well as outdoor and indoor residential concentrations of VOCs for each study participant. In general, personal exposures were greater than indoor VOC concentrations, which were greater than outdoor VOC concentrations. Public health risks due to actual personal exposures were estimated. In comparing measured personal exposures and indoor and outdoor VOC concentrations with ASPEN model estimates for ambient concentrations, our data suggest that ASPEN was reasonably accurate as a surrogate for personal exposures (measured exposures of community residents) for VOCs emitted primarily from mobile sources or VOCs that occur as global "background" source pollutant with no indoor source contributions. Otherwise, the ASPEN model estimates were generally lower than measured personal exposures and the estimated health risks. ASPEN's lower exposures resulted in proportional underestimation of cumulative

  17. Assessing exposures to inhaled complex mixtures.

    PubMed Central

    Leaderer, B P; Lioy, P J; Spengler, J D

    1993-01-01

    In the course of daily activities, individuals spend varying amounts of time in different spaces where they are exposed to a complex mixture of gas, vapor, and particulate contaminants. The term complex is used in this paper to refer to binary mixtures as well as truly complex mixtures of three or more constituents. The diversity of the environments where pollution may occur, the number of pollutants that may be present, and the nature of the activity in the environment combine to pose a challenge to investigators of the health effects of air pollutants. This article discusses several methods of measuring or assessing exposure to complex mixture air contaminants that include time-activity assessments, personal monitoring, biomarkers of exposure, and microenvironmental models that can be employed singly or in combination in a protocol for exposure assessment. The use of nested designs, involving more intensive data collection from samples or subjects, is also considered. PMID:8206025

  18. Health hazards of fire fighters: exposure assessment.

    PubMed Central

    Brandt-Rauf, P W; Fallon, L F; Tarantini, T; Idema, C; Andrews, L

    1988-01-01

    There is growing concern over the detrimental health effects to firefighters produced by exposure to combustion byproducts of burning materials. To assess the types and levels of exposure encountered by firefighters during their routine occupational duties, members of the Buffalo Fire Department were monitored during firefighting activities with personal, portable, ambient environmental sampling devices. The results indicate that firefighters are frequently exposed to significant concentrations of hazardous materials including carbon monoxide, benzene, sulphur dioxide, hydrogen cyanide, aldehydes, hydrogen chloride, dichlorofluoromethane, and particulates. Furthermore, in many cases of the worst exposure to these materials respiratory protective equipment was not used owing to the visual impression of low smoke intensity, and thus these levels represent actual direct exposure of the firefighters. Many of these materials have been implicated in the production of cardiovascular, respiratory, or neoplastic diseases, which may provide an explanation for the alleged increased risk for these illnesses among firefighters. PMID:3179235

  19. ELEMENTAL SPECIATION IN ENVIRONMENTAL EXPOSURE ASSESSMENT MATRICES

    EPA Science Inventory

    Arsenic and tin are two trace metals where exposure assessments have moved towards a speciation based approach because the toxicity is very chemical form dependent. This toxicity difference can be one of many factors which influence the formulation of certain regulations. For a...

  20. Approaches to environmental exposure assessment in children.

    PubMed Central

    Weaver, V M; Buckley, T J; Groopman, J D

    1998-01-01

    An improved understanding of the contribution made by environmental exposures to disease burden in children is essential, given current increasing rates of childhood illnesses such asthma and cancer. Children must be routinely included in environmental research. Exposure assessment, both external (e.g., air, water) and internal dose (e.g., biomarkers), is an integral component of such research. Biomarker measurement has some advantages that are unique in children. These include assessment of potentially increased absorption because of behaviors that differ from adults (i.e., hand-to-mouth activity); metabolite measurement, which can help identify age-related susceptibility differences; and improved assessment of dermal exposure, an important exposure route in children. Environmental exposure assessment in children will require adaption of techniques that are currently applied in adult studies as well as development of tools and validation of strategies that are unique for children. Designs that focus on parent-child study units provide adult comparison data and allow the parent to assist with more complex study designs. Use of equipment that is sized appropriately for children, such as small air pumps and badge monitors, is also important. When biomarkers are used, biologic specimens that can be obtained noninvasively are preferable. Although the current need is primarily for small focused studies to address specific questions and optimize research tools, the future will require establishment of large prospective cohorts. Urban children are an important study cohort because of relatively high morbidity observed in the urban environment. Finally, examples of completed or possible future studies utilizing these techniques are discussed for specific exposures such as benzene, environmental tobacco smoke, aflatoxin, volatile organic compounds, and polycyclic aromatic hydrocarbons. PMID:9646045

  1. Integrated Environmental Assessment Part III: ExposureAssessment

    SciTech Connect

    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

  2. Exposure Assessment of Chemicals from Packaging Materials

    NASA Astrophysics Data System (ADS)

    Poças, Maria De Fátima; Hogg, Timothy

    A variety of chemicals may enter our food supply, by means of intentional or unintentional addition, at different stages of the food chain. These chemicals include food additives, pesticide residues, environmental contaminants, mycotox-ins, flavoring substances, and micronutrients. Packaging systems and other food-contact materials are also a source of chemicals contaminating food products and beverages. Monitoring exposure to these chemicals has become an integral part of ensuring the safety of the food supply. Within the context of the risk analysis approach and more specifically as an integral part of risk assessment procedures, the exercise known as exposure assessment is crucial in providing data to allow sound judgments concerning risks to human health. The exercise of obtaining this data is part of the process of revealing sources of contamination and assessing the effectiveness of strategies for minimizing the risk from chemical contamination in the food supply (Lambe, 2002).

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

    EPA Science Inventory

    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. [Algorithm for assessment of exposure to asbestos].

    PubMed

    Martines, V; Fioravanti, M; Anselmi, A; Attili, F; Battaglia, D; Cerratti, D; Ciarrocca, M; D'Amelio, R; De Lorenzo, G; Ferrante, E; Gaudioso, F; Mascia, E; Rauccio, A; Siena, S; Palitti, T; Tucci, L; Vacca, D; Vigliano, R; Zelano, V; Tomei, F; Sancini, A

    2010-01-01

    There is no universally approved method in the scientific literature to identify subjects exposed to asbestos and divide them in classes according to intensity of exposure. The aim of our work is to study and develope an algorithm based on the findings of occupational anamnestical information provided by a large group of workers. The algorithm allows to discriminate, in a probabilistic way, the risk of exposure by the attribution of a code for each worker (ELSA Code--work estimated exposure to asbestos). The ELSA code has been obtained through a synthesis of information that the international scientific literature identifies as the most predictive for the onset of asbestos-related abnormalities. Four dimensions are analyzed and described: 1) present and/or past occupation; 2) type of materials and equipment used in performing working activity; 3) environment where these activities are carried out; 4) period of time when activities are performed. Although it is possible to have informations in a subjective manner, the decisional procedure is objective and is based on the systematic evaluation of asbestos exposure. From the combination of the four identified dimensions it is possible to have 108 ELSA codes divided in three typological profiles of estimated risk of exposure. The application of the algorithm offers some advantages compared to other methods used for identifying individuals exposed to asbestos: 1) it can be computed both in case of present and past exposure to asbestos; 2) the classification of workers exposed to asbestos using ELSA code is more detailed than the one we have obtained with Job Exposure Matrix (JEM) because the ELSA Code takes in account other indicators of risk besides those considered in the JEM. This algorithm was developed for a project sponsored by the Italian Armed Forces and is also adaptable to other work conditions for in which it could be necessary to assess risk for asbestos exposure.

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

    SciTech Connect

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

    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

  6. Biomonitoring - An Exposure Science Tool for Exposure and Risk Assessment

    EPA Science Inventory

    Biomonitoring studies of environmental stressors are useful for confirming exposures, estimating dose levels, and evaluating human health risks. However, the complexities of exposure-biomarker and biomarker-response relationships have limited the use of biomarkers in exposure sc...

  7. Assessing occupational exposure to sea lamprey pesticides

    PubMed Central

    Ceballos, Diana M; Beaucham, Catherine C; Kurtz, Kristine; Musolin, Kristin

    2015-01-01

    Background: Sea lampreys are parasitic fish found in lakes of the United States and Canada. Sea lamprey is controlled through manual application of the pesticides 3-trifluoromethyl-4-nitrophenol (TFM) and BayluscideTM into streams and tributaries. 3-Trifluoromethyl-4-nitrophenol may cause irritation and central nervous system depression and Bayluscide may cause irritation, dermatitis, blisters, cracking, edema, and allergic skin reactions. Objectives: To assess occupational exposures to sea lamprey pesticides. Methods: We developed a wipe method for evaluating surface and skin contamination with these pesticides. This method was field tested at a biological field station and at a pesticide river application. We also evaluated exposures using control banding tools. Results: We verified TFM surface contamination at the biological station. At the river application, we found surfaces and worker’s skin contaminated with pesticides. Conclusion: We recommended minimizing exposures by implementing engineering controls and improved use of personal protective equipment. PMID:25730600

  8. Conceptual model for assessment of dermal exposure

    PubMed Central

    Schneider, T.; Vermeulen, R.; Brouwer, D. H.; Cherrie, J. W.; Kromhout, H.; Fogh, C. L.

    1999-01-01

    Dermal exposure, primarily to pesticides, has been measured for almost half a century. Compared with exposure by inhalation, limited progress has been made towards standardisation of methods of measurement and development of biologically relevant exposure measures. It is suggested that the absence of a consistent terminology and a theoretical model has been an important cause of this lack of progress. Therefore, a consistent terminology based on a multicompartment model for assessment of dermal exposure is proposed that describes the transport of contaminant mass from the source of the hazardous substance to the surface of the skin. Six compartments and two barriers together with eight mass transport processes are described. With the model structure, examples are given of what some existing methods actually measure and where there are limited, or no, methods for measuring the relevant mass in a compartment or transport of mass. The importance of measuring the concentration of contaminant and not mass per area in the skin contaminant layer is stressed, as it is the concentration difference between the skin contamination layer and the perfused tissue that drives uptake. Methods for measuring uptake are currently not available. Measurement of mass, concentration, and the transport processes must be based on a theoretical model. Standardisation of methods of measurement of dermal exposure is strongly recommended.   PMID:10658563

  9. A Biomonitoring Framework to Support Exposure and Risk Assessments

    EPA Science Inventory

    Background - Biomonitoring is used in exposure and risk assessments to reduce uncertainties along the source-to-outcome continuum. Specifically, biomarkers can help identify exposure sources, routes, and distributions, and reflect kinetic and dynamic processes following exposure ...

  10. Exposure assessment of aluminum arc welding radiation.

    PubMed

    Peng, Chiung-yu; Lan, Cheng-hang; Juang, Yow-jer; Tsao, Ta-ho; Dai, Yu-tung; Liu, Hung-hsin; Chen, Chiou-jong

    2007-10-01

    The purpose of this study is to evaluate the non-ionizing radiation (NIR) exposure, especially optical radiation levels, and potential health hazard from aluminum arc welding processes based on the American Conference of Governmental Industrial Hygienists (ACGIH) method. The irradiance from the optical radiation emissions can be calculated with various biological effective parameters [i.e., S(lambda), B(lambda), R(lambda)] for NIR hazard assessments. The aluminum arc welding processing scatters bright light with NIR emission including ultraviolet radiation (UVR), visible, and infrared spectra. The UVR effective irradiance (Eeff) has a mean value of 1,100 microW cm at 100 cm distance from the arc spot. The maximum allowance time (tmax) is 2.79 s according to the ACGIH guideline. Blue-light hazard effective irradiance (EBlue) has a mean value of 1840 microW cm (300-700 nm) at 100 cm with a tmax of 5.45 s exposure allowance. Retinal thermal hazard effective calculation shows mean values of 320 mW cm(-2) sr(-1) and 25.4 mW (cm-2) (380-875 nm) for LRetina (spectral radiance) and ERetina (spectral irradiance), respectively. From this study, the NIR measurement from welding optical radiation emissions has been established to evaluate separate types of hazards to the eye and skin simultaneously. The NIR exposure assessment can be applied to other optical emissions from industrial sources. The data from welding assessment strongly suggest employees involved in aluminum welding processing must be fitted with appropriate personal protection devices such as masks and gloves to prevent serious injuries of the skin and eyes upon intense optical exposure.

  11. 30 CFR 62.110 - Noise exposure assessment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Noise exposure assessment. 62.110 Section 62... REGULATIONS OCCUPATIONAL NOISE EXPOSURE § 62.110 Noise exposure assessment. (a) The mine operator must establish a system of monitoring that evaluates each miner's noise exposure sufficiently to...

  12. 30 CFR 62.110 - Noise exposure assessment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Noise exposure assessment. 62.110 Section 62... REGULATIONS OCCUPATIONAL NOISE EXPOSURE § 62.110 Noise exposure assessment. (a) The mine operator must establish a system of monitoring that evaluates each miner's noise exposure sufficiently to...

  13. EXPOSURE ASSESSMENT METHODS DEVELOPMENT PILOTS FOR THE NATIONAL CHILDREN'S STUDY

    EPA Science Inventory

    Accurate exposure classification tools are needed to link exposure with health effects. EPA began methods development pilot studies in 2000 to address general questions about exposures and outcome measures. Selected pilot studies are highlighted in this poster. The “Literature Re...

  14. Determining the exposure factors of personal and home care products for exposure assessment.

    PubMed

    Park, Ji Young; Lee, Kiyoung; Hwang, Yunhyung; Kim, Jin Hee

    2015-03-01

    An accurate understanding of the usage patterns of consumer products is important for realistic exposure assessment. Since such patterns differ by country, a Korean national database for exposure factors is needed. We determined the exposure factors of 10 consumer products (face cleanser, toothpaste, shampoo, hair conditioner, body wash, dish and laundry detergents, fabric deodorizer, antistatic spray, and shoe polish. Field survey staff visited homes and collected product use information by questionnaire. In total, 816 men and 2517 women aged 15 years and older from 2500 households completed the questionnaire. Field technicians also re-visited 85 households to investigate the circumstances of use and the reliability of the questionnaire data. Greater than 97% of the sampled population reported use of toothpaste and shampoo. Hair conditioner, body wash, and face cleanser were used by ~60% of the population and by specific age groups and genders. The amount of consumer products used was comparable between that reported in the questionnaire and that measured directly during house visits, and the ratios of usage amounts ranged from 0.75 to 1.69. The exposure factor data obtained from this study could be useful for regulatory agencies when setting safety guidelines for product use.

  15. Determining the exposure factors of personal and home care products for exposure assessment.

    PubMed

    Park, Ji Young; Lee, Kiyoung; Hwang, Yunhyung; Kim, Jin Hee

    2015-03-01

    An accurate understanding of the usage patterns of consumer products is important for realistic exposure assessment. Since such patterns differ by country, a Korean national database for exposure factors is needed. We determined the exposure factors of 10 consumer products (face cleanser, toothpaste, shampoo, hair conditioner, body wash, dish and laundry detergents, fabric deodorizer, antistatic spray, and shoe polish. Field survey staff visited homes and collected product use information by questionnaire. In total, 816 men and 2517 women aged 15 years and older from 2500 households completed the questionnaire. Field technicians also re-visited 85 households to investigate the circumstances of use and the reliability of the questionnaire data. Greater than 97% of the sampled population reported use of toothpaste and shampoo. Hair conditioner, body wash, and face cleanser were used by ~60% of the population and by specific age groups and genders. The amount of consumer products used was comparable between that reported in the questionnaire and that measured directly during house visits, and the ratios of usage amounts ranged from 0.75 to 1.69. The exposure factor data obtained from this study could be useful for regulatory agencies when setting safety guidelines for product use. PMID:25582860

  16. A tiered approach for assessing children's exposure.

    PubMed Central

    Armstrong, T W; Hushka, L J; Tell, J G; Zaleski, R T

    2000-01-01

    Recently, intense attention has been given to children's health issues, particularly in the use of consumer products. Because of this attention, researchers have been planning and initiating studies specifically aimed at developing both toxicology data and exposure data directed to improve our understanding of industrial and consumer product chemical impacts on children's health. To ensure that this research is focused on the highest priority chemicals, we present a methodology for determining and prioritizing the higher hazard chemicals and scenarios for which children could be disproportionately or highly exposed. This tiered approach includes a screening step for initial chemical selection, a hazard assessment based on no- or lowest-observed-adverse-effect levels, and a margin of exposure (MOE) calculation. The initial chemical screen focuses on the chemical presence in specific media that are special to children, such as foods children regularly eat and drink, residential or school air, products children use, and soil and dust in and around residences. Data from the literature or from models serve as the initial exposure estimate. This methodology would allow us to focus on those chemicals to which children are most exposed that are also associated with, potentially, the highest risk. Use of the MOE calculation allows for comparison among chemicals, prioritization of chemicals for evaluation and testing, and identification of significant data gaps. PMID:10856018

  17. Occupational exposure to environmental tobacco smoke and health risk assessment.

    PubMed Central

    Jaakkola, M S; Samet, J M

    1999-01-01

    This article addresses concepts of environmental tobacco smoke (ETS) exposure assessment relevant for health risk assessment based on human studies. We present issues that should be considered when selecting a method for ETS exposure assessment for the purposes of health risk assessment and review data on ETS exposure levels in the workplace and in home environments. Two types of estimates are needed for a quantitative risk assessment of the health effects resulting from occupational ETS exposure: (italic)a(/italic)) an unbiased estimate of the exposure-effect (or dose-response) relation between ETS and the health effect of interest, and (italic)b(/italic)) estimates of the distribution of ETS exposure in different workplaces. By combining the estimated exposure-effect relation with information on exposure distribution for a population of interest, we can calculate the proportions of disease cases attributable to occupational ETS exposure as well as the excess number of cases due to specified exposure conditions. Several dimensions of the exposure profile should be considered when assessing ETS exposure for estimating the exposure-effect relation, including the magnitude of exposure and the biologically relevant time specificity of exposure. The magnitude of exposure is determined by the ETS source strength, environmental factors modifying concentrations, and duration of exposure. Time specificity considerations include the latency period for each health outcome of interest, the time-exposure profile relevant for different disease mechanisms, and the sensitive age period with regard to health effects. The most appropriate indicator of ETS exposure depends on these factors and on the time period that can be assessed with different methods. Images Figure 1 Figure 3 Figure 4 PMID:10592138

  18. SPECIES SPECIFIC DIETARY ARSENIC EXPOSURE ASSESSMENT: THE NEED TO ESTIMATE BIOACCESSIBILITY AND ASSESSING THE IMPLIED PRESYSTEMIC METABOLISM IMPLICATIONS

    EPA Science Inventory

    The chemical form specific toxicity of arsenic dictates the need for species specific quantification in order to accurately assess the risk from an exposure. The literature has begun to produce preliminary species specific databases for certain dietary sources, but a quantitativ...

  19. NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY (NHEXAS): OPPORTUNITIES AND LESSONS LEARNED

    EPA Science Inventory

    The National Human Exposure Assessment Survey (NHEXAS) in its fullest sense is a conceptual design, which upon implementation, will have long-term implications to exposure research and assessment. The ultimate goal is to document national distribution of human exposure to pote...

  20. Pesticide exposure, safety issues, and risk assessment indicators.

    PubMed

    Damalas, Christos A; Eleftherohorinos, Ilias G

    2011-05-01

    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

  1. Pesticide Exposure, Safety Issues, and Risk Assessment Indicators

    PubMed Central

    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

  2. Assessment of human exposure to gaseous pollutants

    SciTech Connect

    Baskin, L.B.; Falco, J.W. )

    1989-09-01

    A mathematical model to aid in assessment of human environmental exposure to volatile organic substances is presented. The model simulates the convective and diffusive transport of gas from the ambient environment into the human body by way of the respiratory and circulatory systems. Data required include easily obtained physical and chemical properties of substances as well as several estimated or measured physiological parameters. Transient and steady-state tissue concentrations resulting from an input atmospheric partial pressure are predicted. From these concentrations, an effective dose may be calculated, allowing for the determination of an exposure-response relationship based upon independently obtained dose-response data. The model's results compare favorably to experimental data on oxygen and halothane. Steady-state conditions are reached very rapidly. These results suggest that uptake of these substances is limited by both ventilation and perfusion. Rates are demonstrated to be essentially linear within the current neighborhoods. Conditions in which the primary processes of ventilation, diffusion, perfusion, and elimination limit uptake of gases are considered. Expressions describing the conditions necessary for a single process to limit gas uptake are derived. Accompanying equations for estimating tissue concentrations under these limiting conditions are presented.

  3. INHALATION EXPOSURE-RESPONSE ASSESSMENTS FOR FIVE CHEMICALS

    EPA Science Inventory

    Inhalation exposure-response assessments for five chemicals (acrolein, ethylene oxide, hexachlorocyclopentadiene, hydrogen sulfide, and phosgene) for less-than-lifetime durations are being developed to inform the development of the Inhalation Exposure-Response Analysis Methodolog...

  4. ALVEOLAR BREATH SAMPLING AND ANALYSIS IN HUMAN EXPOSURE ASSESSMENT STUDIES

    EPA Science Inventory

    Alveolar breath sampling and analysis can be extremely useful in exposure assessment studies involving volatile organic compounds (VOCs). Over recent years scientists from the EPA's National Exposure Research Laboratory have developed and refined an alveolar breath collection ...

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

    EPA Science Inventory

    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...

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

    PubMed Central

    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

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

    PubMed

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

    2016-07-22

    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.

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

    PubMed

    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

  9. Human exposure assessment: a graduate level course

    SciTech Connect

    Lioy, P.J. )

    1991-07-01

    The course has been offered three times. The content and the approach to each lecture has evolved after each time it was given. This is not unexpected since the field has been undergoing major transformations, and new approaches to measurement and modeling are being applied to current problems. The most recent student evaluation, 1990, indicates a difficulty rating of just right' (70%) to difficult' (30%). Most felt the course stimulated their interest in the topic (72%) and the examinations were learning experiences as well as a grading exercise. The major need for the discipline is an adequate text book. The GRAPE program has excellent potential as an educational tool, but it needs to make more interactions and allow introduction of activities and data. The major strengths of the course are the problems provided to the students for homework. These give the student quantitative perspective on the concepts, range in values, variables, and uncertainties necessary to complete an assessment. In addition, the development of the mathematical and conceptional continuum for placing exposure assessment in the context of toxicology, environmental science, epidemiology, and clinical intervention provides a basic framework for the discipline.

  10. Sewage sludge toxicity assessment using earthworm Eisenia fetida: can biochemical and histopathological analysis provide fast and accurate insight?

    PubMed

    Babić, S; Barišić, J; Malev, O; Klobučar, G; Popović, N Topić; Strunjak-Perović, I; Krasnići, N; Čož-Rakovac, R; Klobučar, R Sauerborn

    2016-06-01

    Sewage sludge (SS) is a complex organic by-product of wastewater treatment plants. Deposition of large amounts of SS can increase the risk of soil contamination. Therefore, there is an increasing need for fast and accurate assessment of SS toxic potential. Toxic effects of SS were tested on earthworm Eisenia fetida tissue, at the subcellular and biochemical level. Earthworms were exposed to depot sludge (DS) concentration ratio of 30 or 70 %, to undiluted and to 100 and 10 times diluted active sludge (AS). The exposure to DS lasted for 24/48 h (acute exposure), 96 h (semi-acute exposure) and 7/14/28 days (sub-chronic exposure) and 48 h for AS. Toxic effects were tested by the measurements of multixenobiotic resistance mechanism (MXR) activity and lipid peroxidation levels, as well as the observation of morphological alterations and behavioural changes. Biochemical markers confirmed the presence of MXR inhibitors in the tested AS and DS and highlighted the presence of SS-induced oxidative stress. The MXR inhibition and thiobarbituric acid reactive substance (TBARS) concentration in the whole earthworm's body were higher after the exposition to lower concentration of the DS. Furthermore, histopathological changes revealed damage to earthworm body wall tissue layers as well as to the epithelial and chloragogen cells in the typhlosole region. These changes were proportional to SS concentration in tested soils and to exposure duration. Obtained results may contribute to the understanding of SS-induced toxic effects on terrestrial invertebrates exposed through soil contact and to identify defence mechanisms of earthworms. PMID:26971513

  11. Implementation and validation of a modeling framework to assess personal exposure to black carbon.

    PubMed

    Dons, Evi; Van Poppel, Martine; Kochan, Bruno; Wets, Geert; Int Panis, Luc

    2014-01-01

    Because people tend to move from one place to another during the day, their exposure to air pollution will be determined by the concentration at each location combined with the exposure encountered in transport. In order to estimate the exposure of individuals in a population more accurately, the activity-based modeling framework for Black Carbon exposure assessment, AB(2)C, was developed. An activity-based traffic model was applied to model the whereabouts of individual agents. Exposure to black carbon (BC) in different microenvironments is assessed with a land use regression model, combined with a fixed indoor/outdoor factor for exposure in indoor environments. To estimate exposure in transport, a separate model was used taking into account transport mode, timing of the trip and degree of urbanization. The modeling framework is validated using weeklong time-activity diaries and BC exposure as revealed from a personal monitoring campaign with 62 participants. For each participant in the monitoring campaign, a synthetic population of 100 model-agents per day was made up with all agents meeting similar preconditions as each real-life agent. When these model-agents pass through every stage of the modeling framework, it results in a distribution of potential exposures for each individual. The AB(2)C model estimates average personal exposure slightly more accurately compared to ambient concentrations as predicted for the home subzone; however the added value of a dynamic model lies in the potential for detecting short term peak exposures rather than modeling average exposures. The latter may bring new opportunities to epidemiologists: studying the effect of frequently repeated but short exposure peaks on long term exposure and health. PMID:24161448

  12. Implications of uncertainty in exposure assessment for groundwater contamination

    USGS Publications Warehouse

    Reichard, Eric G.; Izbicki, John A.; Martin, Peter

    1995-01-01

    Decision-making on regulation, mitigation, and treatment of drinking water contamination depends, in part, on estimates of human exposure. Assessment of past, present and potential future exposure levels requires quantitative characterization of the contaminant sources, the transport of contaminants and the level of actual human exposure to the contaminated water. Failure to consider the uncertainties in these three components of exposure assessment can lead to poor decisions such as implementing an inappropriate mitigation strategy or failing to regulate an important contaminant. Three examples from US Geological Survey hydrogeologic studies in southern California are presented to illustrate some of the unique uncertainties associated with exposure assessment for groundwater contamination.

  13. Exposure Reconstruction: A Framework of Advancing Exposure Assessment

    EPA Science Inventory

    The U.S. Environmental Protection Agency’s (EPA) primary goal for environmental protection is to eliminate or minimize the exposure of humans and ecosystems to potential contaminants. With the number of environmental contaminants increasing annually – more than 2000 new chemical...

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

    PubMed Central

    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.

    2014-01-01

    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. PMID:24840353

  15. Assessment and control of fetal exposure

    SciTech Connect

    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.

  16. The accurate assessment of small-angle X-ray scattering data

    SciTech Connect

    Grant, Thomas D.; Luft, Joseph R.; Carter, Lester G.; Matsui, Tsutomu; Weiss, Thomas M.; Martel, Anne; Snell, Edward H.

    2015-01-01

    A set of quantitative techniques is suggested for assessing SAXS data quality. These are applied in the form of a script, SAXStats, to a test set of 27 proteins, showing that these techniques are more sensitive than manual assessment of data quality. Small-angle X-ray scattering (SAXS) has grown in popularity in recent times with the advent of bright synchrotron X-ray sources, powerful computational resources and algorithms enabling the calculation of increasingly complex models. However, the lack of standardized data-quality metrics presents difficulties for the growing user community in accurately assessing the quality of experimental SAXS data. Here, a series of metrics to quantitatively describe SAXS data in an objective manner using statistical evaluations are defined. These metrics are applied to identify the effects of radiation damage, concentration dependence and interparticle interactions on SAXS data from a set of 27 previously described targets for which high-resolution structures have been determined via X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. The studies show that these metrics are sufficient to characterize SAXS data quality on a small sample set with statistical rigor and sensitivity similar to or better than manual analysis. The development of data-quality analysis strategies such as these initial efforts is needed to enable the accurate and unbiased assessment of SAXS data quality.

  17. AN APPROACH TO METHODS DEVELOPMENT FOR HUMAN EXPOSURE ASSESSMENT STUDIES

    EPA Science Inventory

    Human exposure assessment studies require methods that are rapid, cost-effective and have a high sample through-put. The development of analytical methods for exposure studies should be based on specific information for individual studies. Human exposure studies suggest that di...

  18. Challenges in Dietary Exposure Assessment in Epidemiology: Research Trends.

    PubMed

    Ishihara, Junko

    2015-01-01

    Although exposure assessment of the usual diet is an essential component of nutrition epidemiology, it remains one of the most challenging issues in the field. Dietary exposure is widely measured using Food Frequency Questionnaires (FFQs), which impose a low burden on respondents and are inexpensive in large-scale studies. FFQs have long satisfied the needs of epidemiological research, and have helped deliver the tremendous recent growth in knowledge of the diet-disease association. However, issues surrounding measurement errors with FFQs have attracted substantial research interest around the world. Attenuation of the diet-disease association due to measurement errors identified in Western populations has led to extended methodological investigations comparing the performance of FFQs with biomarkers. The need for better dietary assessment methods has increased. Dietary records or recall provide relatively accurate estimates of intake for specific days, and of the usual diet if collected on multiple days. Until recently, however, their use in large-scale studies was not feasible, mainly due to cost. One innovative tool which may overcome the limitations of dietary records or recall is computerized 24-h dietary recall systems. These systems have been demonstrated to provide high-quality dietary intake data among Western populations. Incorporation of such new technology into large-scale epidemiological studies would make multiple-day administration of 24-h recall feasible in terms of cost. Research efforts to improve dietary assessment among Japanese and Asian populations are still under development. The development of innovative methods for Japanese remains an urgent research challenge. PMID:26598878

  19. Analysis of continuous oxygen saturation data for accurate representation of retinal exposure to oxygen in the preterm infant.

    PubMed

    Cirelli, Josie; McGregor, Carolyn; Graydon, Brenda; James, Andrew

    2013-01-01

    Maintaining blood oxygen saturation within the intended target range for preterm infants receiving neonatal intensive care is challenging. Supplemental oxygen is believed to lead to increased risk of retinopathy of prematurity and hence managing the level of oxygen within this population is important within their care. Current quality improvement activities use coarse hourly spot readings to measure supplemental oxygen levels as associated with targeted ranges that vary based on gestational age. In this research we use Artemis, a real-time online healthcare analytics platform to ascertain if the collection of second by second data provides a better representation of retinal exposure to oxygen than an infrequent, intermittent spot reading. We show that Artemis is capable of producing more accurate information from the higher frequency data, as it includes all the episodic events in the activity of the hour, which provides a better understanding of oxygen fluctuation ranges which affect the physiological status of the infant.

  20. Using fatty acids to fingerprint biofilm communities: a means to quickly and accurately assess stream quality.

    PubMed

    DeForest, Jared L; Drerup, Samuel A; Vis, Morgan L

    2016-05-01

    The assessment of lotic ecosystem quality plays an essential role to help determine the extent of environmental stress and the effectiveness of restoration activities. Methods that incorporate biological properties are considered ideal because they provide direct assessment of the end goal of a vigorous biological community. Our primary objective was to use biofilm lipids to develop an accurate biomonitoring tool that requires little expertise and time to facilitate assessment. A model was created of fatty acid biomarkers most associated with predetermined stream quality classification, exceptional warm water habitat (EWH), warm water habitat (WWH), and limited resource (LR-AMD), and validated along a gradient of known stream qualities. The fatty acid fingerprint of the biofilm community was statistically different (P = 0.03) and was generally unique to recognized stream quality. One striking difference was essential fatty acids (DHA, EPA, and ARA) were absent from LR-AMD and only recovered from WWH and EWH, 45 % more in EWH than WWH. Independently testing the model along a stream quality gradient, this model correctly categorized six of the seven sites, with no match due to low sample biomass. These results provide compelling evidence that biofilm fatty acid analysis can be a sensitive, accurate, and cost-effective biomonitoring tool. We conceive of future studies expanding this research to more in-depth studies of remediation efforts, determining the applicable geographic area for the method and the addition of multiple stressors with the possibility of distinguishing among stressors.

  1. Assessing Children's Exposure to Intimate Partner Violence

    ERIC Educational Resources Information Center

    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…

  2. Assessment of Violence Exposure among Residential Children and Adolescents

    ERIC Educational Resources Information Center

    Singer, Mark I.

    2007-01-01

    Childhood victimization is an important factor in assessing children in residential treatment. These children often have extensive histories of abuse and neglect, and are of high risk for violence exposure in their schools and neighborhoods. This article describes the concept of exposure to community violence, and its importance in assessing and…

  3. Accurate assessment of Congo basin forest carbon stocks requires forest type specific assessments

    NASA Astrophysics Data System (ADS)

    Moonen, Pieter C. J.; Van Ballaert, Siege; Verbist, Bruno; Boyemba, Faustin; Muys, Bart

    2014-05-01

    carbon stocks despite poorer physical and chemical soil properties. Soil organic carbon stocks (0-100cm) did not significantly differ between forest types and were estimated at 109 ± 35 Mg C ha-1. Our results confirm recent findings of significantly lower carbon stocks in the Central Congo Basin as compared to the outer regions and of the importance of local tree height-diameter relationships for accurate carbon stock estimations.

  4. Human exposure assessment resources on the World Wide Web.

    PubMed

    Schwela, Dieter; Hakkinen, Pertti J

    2004-05-20

    Human exposure assessment is frequently noted as a weak link and bottleneck in the risk assessment process. Fortunately, the World Wide Web and Internet are providing access to numerous valuable sources of human exposure assessment-related information, along with opportunities for information exchange. Internet mailing lists are available as potential online help for exposure assessment questions, e.g. RISKANAL has several hundred members from numerous countries. Various Web sites provide opportunities for training, e.g. Web sites offering general human exposure assessment training include two from the US Environmental Protection Agency (EPA) and four from the US National Library of Medicine. Numerous other Web sites offer access to a wide range of exposure assessment information. For example, the (US) Alliance for Chemical Awareness Web site addresses direct and indirect human exposures, occupational exposures and ecological exposure assessments. The US EPA's Exposure Factors Program Web site provides a focal point for current information and data on exposure factors relevant to the United States. In addition, the International Society of Exposure Analysis Web site provides information about how this society seeks to foster and advance the science of exposure analysis. A major opportunity exists for risk assessors and others to broaden the level of exposure assessment information available via Web sites. Broadening the Web's exposure information could include human exposure factors-related information about country- or region-specific ranges in body weights, drinking water consumption, etc. along with residential factors-related information on air changeovers per hour in various types of residences. Further, country- or region-specific ranges on how various tasks are performed by various types of consumers could be collected and provided. Noteworthy are that efforts are underway in Europe to develop a multi-country collection of exposure factors and the European

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

    PubMed

    Van-Wendel-de-Joode, Berna; Brouwer, Derk H; Vermeulen, Roel; Van Hemmen, Joop J; Heederik, Dick; Kromhout, Hans

    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, resulting in a ranking of tasks and subsequently jobs. DREAM consists of an inventory and evaluation part. Two examples of dermal exposure of workers of a car-construction company show that DREAM characterizes tasks and gives insight into exposure mechanisms, forming a basis for systematic exposure reduction. DREAM supplies estimates for exposure levels on the outside clothing layer as well as on skin, and provides insight into the distribution of dermal exposure over the body. Together with the ranking of tasks and people, this provides information for measurement strategies and helps to determine who, where and what to measure. In addition to dermal exposure assessment, the systematic description of dermal exposure pathways helps to prioritize and determine most adequate measurement strategies and methods. DREAM could be a promising approach for structured, semi-quantitative, dermal exposure assessment. PMID:12505908

  6. Assessing exposure to phthalates - the human biomonitoring approach.

    PubMed

    Wittassek, Matthias; Koch, Holger Martin; Angerer, Jürgen; Brüning, Thomas

    2011-01-01

    Some phthalates are developmental and reproductive toxicants in animals. Exposure to phthalates is considered to be potentially harmful to human health as well. Based on a comprehensive literature research, we present an overview of the sources of human phthalate exposure and results of exposure assessments with special focus on human biomonitoring data. Among the general population, there is widespread exposure to a number of phthalates. Foodstuff is the major source of phthalate exposure, particularly for the long-chain phthalates such as di(2-ethylhexyl) phthalate. For short-chain phthalates such as di-n-butyl-phthalate, additional pathways are of relevance. In general, children are exposed to higher phthalate doses than adults. Especially, high exposures can occur through some medications or medical devices. By comparing exposure data with existing limit values, one can also assess the risks associated with exposure to phthalates. Within the general population, some individuals exceed tolerable daily intake values for one or more phthalates. In high exposure groups, (intensive medical care, medications) tolerable daily intake transgressions can be substantial. Recent findings from animal studies suggest that a cumulative risk assessment for phthalates is warranted, and a cumulative exposure assessment to phthalates via human biomonitoring is a major step into this direction.

  7. Advanced REACH Tool: a Bayesian model for occupational exposure assessment.

    PubMed

    McNally, Kevin; Warren, Nicholas; Fransman, Wouter; Entink, Rinke Klein; Schinkel, Jody; van Tongeren, Martie; Cherrie, John W; Kromhout, Hans; Schneider, Thomas; Tielemans, Erik

    2014-06-01

    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 sources of information within a Bayesian statistical framework. The information is obtained from expert knowledge expressed in a calibrated mechanistic model of exposure assessment, data on inter- and intra-individual variability in exposures from the literature, and context-specific exposure measurements. The ART provides central estimates and credible intervals for different percentiles of the exposure distribution, for full-shift and long-term average exposures. The ART can produce exposure estimates in the absence of measurements, but the precision of the estimates improves as more data become available. The methodology presented in this paper is able to utilize partially analogous data, a novel approach designed to make efficient use of a sparsely populated measurement database although some additional research is still required before practical implementation. The methodology is demonstrated using two worked examples: an exposure to copper pyrithione in the spraying of antifouling paints and an exposure to ethyl acetate in shoe repair. PMID:24665110

  8. PROBABILISTIC MODELING FOR ADVANCED HUMAN EXPOSURE ASSESSMENT

    EPA Science Inventory

    Human exposures to environmental pollutants widely vary depending on the emission patterns that result in microenvironmental pollutant concentrations, as well as behavioral factors that determine the extent of an individual's contact with these pollutants. Probabilistic human exp...

  9. The accurate assessment of small-angle X-ray scattering data

    DOE PAGES

    Grant, Thomas D.; Luft, Joseph R.; Carter, Lester G.; Matsui, Tsutomu; Weiss, Thomas M.; Martel, Anne; Snell, Edward H.

    2015-01-23

    Small-angle X-ray scattering (SAXS) has grown in popularity in recent times with the advent of bright synchrotron X-ray sources, powerful computational resources and algorithms enabling the calculation of increasingly complex models. However, the lack of standardized data-quality metrics presents difficulties for the growing user community in accurately assessing the quality of experimental SAXS data. Here, a series of metrics to quantitatively describe SAXS data in an objective manner using statistical evaluations are defined. These metrics are applied to identify the effects of radiation damage, concentration dependence and interparticle interactions on SAXS data from a set of 27 previously described targetsmore » for which high-resolution structures have been determined via X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. Studies show that these metrics are sufficient to characterize SAXS data quality on a small sample set with statistical rigor and sensitivity similar to or better than manual analysis. The development of data-quality analysis strategies such as these initial efforts is needed to enable the accurate and unbiased assessment of SAXS data quality.« less

  10. The accurate assessment of small-angle X-ray scattering data

    SciTech Connect

    Grant, Thomas D.; Luft, Joseph R.; Carter, Lester G.; Matsui, Tsutomu; Weiss, Thomas M.; Martel, Anne; Snell, Edward H.

    2015-01-23

    Small-angle X-ray scattering (SAXS) has grown in popularity in recent times with the advent of bright synchrotron X-ray sources, powerful computational resources and algorithms enabling the calculation of increasingly complex models. However, the lack of standardized data-quality metrics presents difficulties for the growing user community in accurately assessing the quality of experimental SAXS data. Here, a series of metrics to quantitatively describe SAXS data in an objective manner using statistical evaluations are defined. These metrics are applied to identify the effects of radiation damage, concentration dependence and interparticle interactions on SAXS data from a set of 27 previously described targets for which high-resolution structures have been determined via X-ray crystallography or nuclear magnetic resonance (NMR) spectroscopy. Studies show that these metrics are sufficient to characterize SAXS data quality on a small sample set with statistical rigor and sensitivity similar to or better than manual analysis. The development of data-quality analysis strategies such as these initial efforts is needed to enable the accurate and unbiased assessment of SAXS data quality.

  11. Risk assessment and management of radiofrequency radiation exposure

    NASA Astrophysics Data System (ADS)

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

    2013-11-01

    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.

  12. Risk assessment and management of radiofrequency radiation exposure

    SciTech Connect

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

    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.

  13. Application of statistical modeling to occupational exposure assessment

    SciTech Connect

    Nicas, M.

    1991-01-01

    This dissertation applies statistical modeling to two problems: (1) describing a single worker's exposure distribution and estimating its associated arithemetic mean; and (2) describing the distribution of inhalation exposure levels among a population of respirator wearers while accounting for variability in ambient exposure and respirator penetration values within and between wearers. A task-based statistical construct for a single worker's exposure levels for a single agent is developed; the model accounts for variability in short-term time weighted average (TWA) exposure values within a task, and for variability in arithmetic mean exposure levels between tasks. Five sample survey designs for estimating a worker's arithmetic mean exposure level are examined. Stratified random sampling designs, in which short-term TWAs are measured for time periods selected on a task basis, can provide a more precise estimate of the arithmetic mean exposure level than the traditional survey design for the same fixed cost. For describing inhalation exposure levels (C{sub i}) among a population of air-purifying respirator wearers, a synthesis of lognormal one-way analysis of variance models for ambient exposure levels (C.) and respirator penetration (P) values provides the most tractable construct. The model is applied to assessing the risk of toxicant overexposure for a respirator wearer population. Overexposure to a chronic toxicant is equated with an arithmetic mean exposure level above the permissible exposure limit (PEL) value, while overexposure to an acute toxicant is equated with a 95th percentile exposure level above the PEL value.

  14. Probabilistic assessment of exposure to nail cosmetics in French consumers.

    PubMed

    Ficheux, A S; Morisset, T; Chevillotte, G; Postic, C; Roudot, A C

    2014-04-01

    The aim of this study was to assess probabilistic exposure to nail cosmetics in French consumers. The exposure assessment was performed with base coat, polish, top coat and remover. This work was done for adult and child consumers. Dermal, inhalation and oral routes were taken into account for varnishes. Exposure evaluation was performed for the inhalation route with polish remover. The main route of exposure to varnishes was the ungual route. Inhalation was the secondary route of exposure, followed by dermal and oral routes. Polish contributed most to exposure, regardless of the route of exposure. For this nail product, P50 and P95 values by ungual route were respectively equal to 1.74 mg(kg bw week)(-1) and 8.55 mg(kg bw week)(-1) for women aged 18-34 years. Exposure to polish by inhalation route was equal to 0.70 mg(kg bw week)(-1) (P50) and 5.27 mg(kg bw week)(-1) (P95). P50 and P95 values by inhalation route were respectively equal to 0.08 mg(kg bw week)(-1) and 1.14 mg(kg bw week)(-1) for consumers aged 18-34 years exposed to polish remover. This work provided current exposure data for nail cosmetics, and a basis for future toxicological studies of the uptake of substances contained in nail cosmetics in order to assess systemic exposure. PMID:24447976

  15. Probabilistic assessment of exposure to nail cosmetics in French consumers.

    PubMed

    Ficheux, A S; Morisset, T; Chevillotte, G; Postic, C; Roudot, A C

    2014-04-01

    The aim of this study was to assess probabilistic exposure to nail cosmetics in French consumers. The exposure assessment was performed with base coat, polish, top coat and remover. This work was done for adult and child consumers. Dermal, inhalation and oral routes were taken into account for varnishes. Exposure evaluation was performed for the inhalation route with polish remover. The main route of exposure to varnishes was the ungual route. Inhalation was the secondary route of exposure, followed by dermal and oral routes. Polish contributed most to exposure, regardless of the route of exposure. For this nail product, P50 and P95 values by ungual route were respectively equal to 1.74 mg(kg bw week)(-1) and 8.55 mg(kg bw week)(-1) for women aged 18-34 years. Exposure to polish by inhalation route was equal to 0.70 mg(kg bw week)(-1) (P50) and 5.27 mg(kg bw week)(-1) (P95). P50 and P95 values by inhalation route were respectively equal to 0.08 mg(kg bw week)(-1) and 1.14 mg(kg bw week)(-1) for consumers aged 18-34 years exposed to polish remover. This work provided current exposure data for nail cosmetics, and a basis for future toxicological studies of the uptake of substances contained in nail cosmetics in order to assess systemic exposure.

  16. Accuracy of a semiquantitative method for Dermal Exposure Assessment (DREAM)

    PubMed Central

    van Wendel, de Joo... B; Vermeulen, R; van Hemmen, J J; Fransman, W; Kromhout, H

    2005-01-01

    Background: The authors recently developed a Dermal Exposure Assessment Method (DREAM), an observational semiquantitative method to assess dermal exposures by systematically evaluating exposure determinants using pre-assigned default values. Aim: To explore the accuracy of the DREAM method by comparing its estimates with quantitative dermal exposure measurements in several occupational settings. Methods: Occupational hygienists observed workers performing a certain task, whose exposure to chemical agents on skin or clothing was measured quantitatively simultaneously, and filled in the DREAM questionnaire. DREAM estimates were compared with measurement data by estimating Spearman correlation coefficients for each task and for individual observations. In addition, mixed linear regression models were used to study the effect of DREAM estimates on the variability in measured exposures between tasks, between workers, and from day to day. Results: For skin exposures, spearman correlation coefficients for individual observations ranged from 0.19 to 0.82. DREAM estimates for exposure levels on hands and forearms showed a fixed effect between and within surveys, explaining mainly between-task variance. In general, exposure levels on clothing layer were only predicted in a meaningful way by detailed DREAM estimates, which comprised detailed information on the concentration of the agent in the formulation to which exposure occurred. Conclusions: The authors expect that the DREAM method can be successfully applied for semiquantitative dermal exposure assessment in epidemiological and occupational hygiene surveys of groups of workers with considerable contrast in dermal exposure levels (variability between groups >1.0). For surveys with less contrasting exposure levels, quantitative dermal exposure measurements are preferable. PMID:16109819

  17. Assessment of children's long-term exposure to magnetic fields (The Geomet study)

    SciTech Connect

    Koontz, M.D. ); Koontz, M.D.; Mehegan, L.L.; Dietrich, F.M.; Nagda, N.L. )

    1992-11-01

    Past epidemiologic studies have had conflicting results concerning a possible association between childhood cancer and magnetic field exposure, perhaps because indirect measures of exposure were used. This pilot study was conducted to assess day-today and seasonal variations in children's exposure, the contributions of different environments to total exposure, and the level of measurement/observational detail needed to accurately predict or classify children's exposures. Twenty-eight children in two age groups (8 to 11 years and under 4 years) were personally monitored for exposure to magnetic fields. All subjects were monitored for two consecutive days during winter or spring, and 12 of the subjects were monitored during both seasons. Surrogates for exposure were developed from observation of wiring configurations, indoor/outdoor spot measurements of field strength, and continuous stationary monitoring at selected indoor locations in parallel with personal monitoring. The results indicate that a single monitoring episode may be insufficient for characterization of long-term exposure, and spot measurements at one point in time may not be adequate to predict exposure. For this study, wire codes and measures based on parallel stationary monitoring in the child's bedroom were the best surrogates for personal exposure.

  18. Exposure assessment in industry specific retrospective occupational epidemiology studies.

    PubMed Central

    Seixas, N S; Checkoway, H

    1995-01-01

    Quantitative estimation of exposure for occupational epidemiology studies has received increasing attention in recent years and, as a result, a body of methodological literature has begun to take form. This paper reviews the generic issues in the methodology of exposure assessment, particularly methods for quantitative retrospective assessment studies. A simple framework, termed an exposure data matrix (EDM), for defining and analysing exposure data is proposed and discussed in terms of the definition of matrix dimensions and scales. Several methods for estimation, interpolation, and extrapolation, ranging from subjective ratings to quantitative statistical modelling are presented and discussed. The various approaches to exposure assessment based on the EDM concept are illustrated with studies of lung disease among coal miners and other dust and chemically induced chronic occupational diseases. The advantages of validated statistical models are emphasised. The importance of analysis and control of errors in exposure assessments, and integration of the exposure assessment and exposure-response processes, especially for emerging occupational health issues, is emphasised. PMID:7489051

  19. Assessing the risks from exposure to radon in dwellings

    SciTech Connect

    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.

  20. ASSESSING CHILDREN'S EXPOSURES: ISSUES, APPROACHES AND PLANS

    EPA Science Inventory

    Estimation of exposures of children to pesticides requires careful consideration of sources and concentrations of chemicals that may be present in different environmental media and in foods and beverages consumed by children, as well as the different routes and pathways of expo...

  1. Cellular Metabolomics for Exposure and Toxicity Assessment

    EPA Science Inventory

    We have developed NMR automation and cell quench methods for cell culture-based metabolomics to study chemical exposure and toxicity. Our flow automation method is robust and free of cross contamination. The direct cell quench method is rapid and effective. Cell culture-based met...

  2. Environmental Exposure Assessment of Pesticides in Farmworker Homes

    PubMed Central

    Hoppin, Jane A.; Adgate, John L.; Eberhart, Monty; Nishioka, Marcia; Ryan, P. Barry

    2006-01-01

    Farmworkers and their families are exposed to pesticides both at work and in their homes. Environmental exposure assessment provides a means to evaluate pesticides in the environment and human contact with these chemicals through identification of sources and routes of exposure. To date, a variety of methods have been used to assess pesticide exposure among farmworker families, mostly focusing on dust and handwipe samples. While many of the methods are similar, differences in the collection, chemical analysis, and statistical analysis, can limit the comparability of results from farm-worker studies. This mini-monograph discusses the strategies used to assess pesticide exposures, presents limitations in the available data for farmworkers, and suggests research needs for future studies of pesticide exposure among farmworker families. PMID:16759997

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

    PubMed Central

    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 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. PMID:25985312

  4. Assessing therapist reservations about exposure therapy for anxiety disorders: the Therapist Beliefs about Exposure Scale.

    PubMed

    Deacon, Brett J; Farrell, Nicholas R; Kemp, Joshua J; Dixon, Laura J; Sy, Jennifer T; Zhang, Annie R; McGrath, Patrick B

    2013-12-01

    Exposure therapy is underutilized in the treatment of pathological anxiety and is often delivered in a suboptimal manner. Negative beliefs about exposure appear common among therapists and may pose a barrier to its dissemination. To permit reliable and valid assessment of such beliefs, we constructed the 21-item Therapist Beliefs about Exposure Scale (TBES) and examined its reliability and validity in three samples of practicing clinicians. The TBES demonstrated a clear single-factor structure, excellent internal consistency (αs=.90-.96), and exceptionally high six-month test-retest reliability (r=.89). Negative beliefs about exposure therapy were associated with therapist demographic characteristics, negative reactions to a series of exposure therapy case vignettes, and the cautious delivery of exposure therapy in the treatment of a hypothetical client with obsessive-compulsive disorder. Lastly, TBES scores decreased markedly following a didactic workshop on exposure therapy. The present findings support the reliability and validity of the TBES.

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

    PubMed Central

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

    2016-01-01

    Background: 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. Methods: 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. Results: 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

  6. Population Based Exposure Assessment of Bioaccessible Arsenic in Carrots

    EPA Science Inventory

    The two predominant arsenic exposure routes are food and water. Estimating the risk from dietary exposures is complicated, owing to the chemical form dependent toxicity of arsenic and the diversity of arsenicals present in dietary matrices. Two aspects of assessing dietary expo...

  7. USEPA SHEDS MODEL: METHODOLOGY FOR EXPOSURE ASSESSMENT FOR WOOD PRESERVATIVES

    EPA Science Inventory

    A physically-based, Monte Carlo probabilistic model (SHEDS-Wood: Stochastic Human Exposure and Dose Simulation model for wood preservatives) has been applied to assess the exposure and dose of children to arsenic (As) and chromium (Cr) from contact with chromated copper arsenat...

  8. EXPOSURE ASSESSMENT OF PARTICULATE MATTER FOR SUSCEPTIBLE POPULATIONS IN SEATTLE

    EPA Science Inventory

    In this article we present results from a 2-year comprehensive exposure assessment study that examined the particulate matter (PM) exposures and health effects in 108 individuals with and without chronic obstructive pulmonary disease (COPD), coronary heart disease (CHD), and as...

  9. Interoceptive Assessment and Exposure in Panic Disorder: A Descriptive Study

    ERIC Educational Resources Information Center

    Schmidt, Norman B.; Trakowski, Jack

    2004-01-01

    Cognitive behavioral treatment (CBT) protocols for panic disorder (PD) typically include some form of interoceptive exposure (IE)--repeated exposure to internal sensations. Despite the widespread clinical use of IE, there is a notable absence of empirical reports about the nature of interoceptive assessments and IE. The present study was designed…

  10. INDIRECT EXPOSURE ASSESSMENT AT THE U.S. EPA

    EPA Science Inventory

    In the early 1980s, exposures and subsequent health impact assessments from contaminants emitted into the air from stationary sources focused on the inhalation pathway. This 'direct' pathway of exposure was thought to be the most critical pathway, as it is for many contaminants. ...

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

    EPA Science Inventory

    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. Th...

  12. Long maximal incremental tests accurately assess aerobic fitness in class II and III obese men.

    PubMed

    Lanzi, Stefano; Codecasa, Franco; Cornacchia, Mauro; Maestrini, Sabrina; Capodaglio, Paolo; Brunani, Amelia; Fanari, Paolo; Salvadori, Alberto; Malatesta, Davide

    2015-01-01

    This study aimed to compare two different maximal incremental tests with different time durations [a maximal incremental ramp test with a short time duration (8-12 min) (STest) and a maximal incremental test with a longer time duration (20-25 min) (LTest)] to investigate whether an LTest accurately assesses aerobic fitness in class II and III obese men. Twenty obese men (BMI≥35 kg.m-2) without secondary pathologies (mean±SE; 36.7±1.9 yr; 41.8±0.7 kg*m-2) completed an STest (warm-up: 40 W; increment: 20 W*min-1) and an LTest [warm-up: 20% of the peak power output (PPO) reached during the STest; increment: 10% PPO every 5 min until 70% PPO was reached or until the respiratory exchange ratio reached 1.0, followed by 15 W.min-1 until exhaustion] on a cycle-ergometer to assess the peak oxygen uptake [Formula: see text] and peak heart rate (HRpeak) of each test. There were no significant differences in [Formula: see text] (STest: 3.1±0.1 L*min-1; LTest: 3.0±0.1 L*min-1) and HRpeak (STest: 174±4 bpm; LTest: 173±4 bpm) between the two tests. Bland-Altman plot analyses showed good agreement and Pearson product-moment and intra-class correlation coefficients showed a strong correlation between [Formula: see text] (r=0.81 for both; p≤0.001) and HRpeak (r=0.95 for both; p≤0.001) during both tests. [Formula: see text] and HRpeak assessments were not compromised by test duration in class II and III obese men. Therefore, we suggest that the LTest is a feasible test that accurately assesses aerobic fitness and may allow for the exercise intensity prescription and individualization that will lead to improved therapeutic approaches in treating obesity and severe obesity.

  13. RATE Exposure Assessment Modules - EXA 408, EXA 409

    EPA Science Inventory

    EXA 408 – Interpreting Biomonitoring Data and Using Pharmacokinetic Modeling in Exposure Assessment Widespread acceptance and use of the CDC's National Health and Nutritional Examination Survey (NHANES) database, which, among other things, reports measured concentrations of...

  14. ASSESSING RESIDENTIAL EXPOSURE USING THE STOCHASTIC HUMAN EXPOSURE AND DOSE SIMULATION (SHEDS) MODEL

    EPA Science Inventory

    As part of a workshop sponsored by the Environmental Protection Agency's Office of Research and Development and Office of Pesticide Programs, the Aggregate Stochastic Human Exposure and Dose Simulation (SHEDS) Model was used to assess potential aggregate residential pesticide e...

  15. Semi-quantitative exposure assessment of occupational exposure to wood dust and nasopharyngeal cancer risk.

    PubMed

    Ekpanyaskul, Chatchai; Sangrajrang, Suleeporn; Ekburanawat, Wiwat; Brennan, Paul; Mannetje, Andrea; Thetkathuek, Anamai; Saejiw, Nutjaree; Ruangsuwan, Tassanu; Boffetta, Paolo

    2015-01-01

    Occupational exposure to wood dust is one cause of nasopharyngeal cancer (NPC); however, assessing this exposure remains problematic. Therefore, the objective of this study was to develop a semi-quantitative exposure assessment method and then utilize it to evaluate the association between occupational exposure to wood dust and the development of NPC. In addition, variations in risk by histology were examined. A case-control study was conducted with 327 newly diagnosed cases of NPC at the National Cancer Institute and regional cancer centers in Thailand with 1:1 controls matched for age, gender and geographical residence. Occupational information was obtained through personal interviews. The potential probability, frequency and intensity of exposure to wood dust were assessed on a job-by-job basis by experienced experts. Analysis was performed by conditional logistic regression and presented in odds ratio (ORs) estimates and 95% confidence intervals (CI). Overall, a non significant relationship between occupational wood dust exposure and NPC risk for all subjects was observed (ORs=1.61, 95%CI 0.99-2.59); however, the risk became significant when analyses focused on types 2 and 3 of NPC (ORs=1.62, 95%CI 1.03-2.74). The significant association was stronger for those exposed to wood dust for >10 year (ORs=2.26, 95%CI 1.10-4.63), for those with first-time exposure at age>25 year (ORs=2.07, 95%CI 1.08-3.94), and for those who had a high cumulative exposure (ORs=2.17, 95%CI 1.03-4.58) when compared with those considered unexposed. In conclusion, wood dust is likely to be associated with an increased risk of type 2 or 3 NPC in the Thai population. The results of this study show that semi-quantitative exposure assessment is suitable for occupational exposure assessment in a case control study and complements the information from self-reporting.

  16. Assessing inhalation exposure from airborne soil contaminants

    SciTech Connect

    Shinn, J.H.

    1998-04-01

    A method of estimation of inhalation exposure to airborne soil contaminants is presented. this method is derived from studies of airborne soil particles with radioactive tags. The concentration of contaminants in air (g/m{sup 3}) can be derived from the product of M, the suspended respirable dust mass concentration (g/m{sup 3}), S, the concentration of contaminant in the soil (g/g), and E{sub f}, an enhancement factor. Typical measurement methods and values of M, and E{sub f} are given along with highlights of experiences with this method.

  17. Exposure and control assessment of semiconductor manufacturing

    NASA Astrophysics Data System (ADS)

    Jones, James H.

    1988-07-01

    From 1980 to 1984, the National Institute for Occupational Safety and Health (NIOSH), along with the U.S. Environmental Protection Agency (EPA), sponsored a study of worker exposures and controls in semiconductor manufacturing. The study was conducted by Battelle Columbus Laboratories and PEDCO Environmental. Walk-through surveys were conducted at 21 plants and in-depth studies were done at four of these plants. Processes studied included photolithography, chemical vapor deposition, wet chemical etching and cleaning, plasma etching, diffusion, ion implantation, and metallization. Air samples were collected for acetone, antimony, arsenic, boron, n-butyl acetate, diborane, 2-ethoxyethyl acetate, hexamethyldisilizane, hydrogen chloride, hydrogen fluoride, 2-methoxyethanol, methyl ethyl ketone, nitric acid, phosphorus, sulfuric acid, and xylene. In addition, radio-frequency and ionizing radiation were monitored and ventilation measured. In general, results were well below recommended standards for routine operations. One exception was radio-frequency radiation where there was the potential for overexposure in several instances. Worker exposures during maintenance operations and process upset conditions were not able to be evaluated.

  18. Exposure assessment at 30 000 feet: challenges and future directions.

    PubMed

    Grajewski, Barbara; Pinkerton, Lynne E

    2013-07-01

    Few studies of cancer mortality and incidence among flight crew have included a detailed assessment of both occupational exposures and lifestyle factors that may influence the risk of cancer. In this issue, Kojo et al. (Risk factors for skin cancer among Finnish airline cabin crew. Ann Occup. Hyg 2013; 57: 695-704) evaluated the relative contributions of ultraviolet and cosmic radiation to the incidence of skin cancer in Finnish flight attendants. This is a useful contribution, yet the reason flight crew members have an increased risk of skin cancer compared with the general population remains unclear. Good policy decisions for flight crew will depend on continued and emerging effective collaborations to increase study power and improve exposure assessment in future flight crew health studies. Improving the assessment of occupational exposures and non-occupational factors will cost additional time and effort, which are well spent if the role of exposures can be clarified in larger studies. PMID:23818455

  19. Exposure Assessment at 30 000 Feet: Challenges and Future Directions

    PubMed Central

    Grajewski, Barbara; Pinkerton, Lynne E.

    2015-01-01

    Few studies of cancer mortality and incidence among flight crew have included a detailed assessment of both occupational exposures and lifestyle factors that may influence the risk of cancer. In this issue, Kojo et al. (Risk factors for skin cancer among Finnish airline cabin crew. Ann. Occup. Hyg 2013; 57: 695–704) evaluated the relative contributions of ultraviolet and cosmic radiation to the incidence of skin cancer in Finnish flight attendants. This is a useful contribution, yet the reason flight crew members have an increased risk of skin cancer compared with the general population remains unclear. Good policy decisions for flight crew will depend on continued and emerging effective collaborations to increase study power and improve exposure assessment in future flight crew health studies. Improving the assessment of occupational exposures and non-occupational factors will cost additional time and effort, which are well spent if the role of exposures can be clarified in larger studies. PMID:23818455

  20. Perspectives for integrating human and environmental exposure assessments.

    PubMed

    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

  1. Perspectives for integrating human and environmental exposure assessments.

    PubMed

    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

  2. Health and Household Air Pollution from Solid Fuel Use: The Need for Improved Exposure Assessment

    PubMed Central

    Peel, Jennifer L.; Balakrishnan, Kalpana; Breysse, Patrick N.; Chillrud, Steven N.; Naeher, Luke P.; Rodes, Charles E.; Vette, Alan F.; Balbus, John M.

    2013-01-01

    Background: Nearly 3 billion people worldwide rely on solid fuel combustion to meet basic household energy needs. The resulting exposure to air pollution causes an estimated 4.5% of the global burden of disease. Large variability and a lack of resources for research and development have resulted in highly uncertain exposure estimates. Objective: We sought to identify research priorities for exposure assessment that will more accurately and precisely define exposure–response relationships of household air pollution necessary to inform future cleaner-burning cookstove dissemination programs. Data Sources: As part of an international workshop in May 2011, an expert group characterized the state of the science and developed recommendations for exposure assessment of household air pollution. Synthesis: The following priority research areas were identified to explain variability and reduce uncertainty of household air pollution exposure measurements: improved characterization of spatial and temporal variability for studies examining both short- and long-term health effects; development and validation of measurement technology and approaches to conduct complex exposure assessments in resource-limited settings with a large range of pollutant concentrations; and development and validation of biomarkers for estimating dose. Addressing these priority research areas, which will inherently require an increased allocation of resources for cookstove research, will lead to better characterization of exposure–response relationships. Conclusions: Although the type and extent of exposure assessment will necessarily depend on the goal and design of the cookstove study, without improved understanding of exposure–response relationships, the level of air pollution reduction necessary to meet the health targets of cookstove interventions will remain uncertain. Citation: Clark ML, Peel JL, Balakrishnan K, Breysse PN, Chillrud SN, Naeher LP, Rodes CE, Vette AF, Balbus JM. 2013. Health

  3. How accurate are we at assessing others’ well-being? The example of welfare assessment in horses

    PubMed Central

    Lesimple, Clémence; Hausberger, Martine

    2014-01-01

    Healthcare practitioners such as physicians or nurses often underestimate patients’ well-being impairment (e.g., pain, anxiety) which may lead to undesirable consequences on treatment decisions. Lack of recognition/identification of signals and over-exposure are two reasons invoked, but a combination of factors may be involved. Studying human decoding of animals’ expressions of emotions showed that “identification” to the subject was necessary to decode the other’s internal state. In the present study we wanted to compare caretakers’ reports on the prevalence of stereotypic or abnormal repetitive behaviors, to ethological observations performed by an experienced observer on the same horses in order to test the impact of these different factors. On the first hand, a questionnaire was given hand to hand to the caretakers. On the other hand, the experienced observer spent 18 h observing the horses in each stable. Here we show that caretakers strongly underestimate horses’ expressions of well-being impairment. The caretakers who had a strong concern about their horses’ well-being were also those who reported the more accurately SB/ARB’s prevalence, showing that “identification” to the subject is a primary factor of bad-being signal’s detection. Over-exposure also appeared to be involved as no SB/ARB was reported in stables where most of the horses were performing these abnormal behaviors. Being surrounded by a large population of individuals expressing clear signals of bad-being may change professionals’ perceptions of what are behaviors or expressions of well being. These findings are of primary importance as (1) they illustrate the interest of using human-animal relationships to evaluate humans’ abilities to decode others’ states; (2) they put limitations on questionnaire-based studies of welfare. PMID:24478748

  4. Asbestos exposure--quantitative assessment of risk

    SciTech Connect

    Hughes, J.M.; Weill, H.

    1986-01-01

    Methods for deriving quantitative estimates of asbestos-associated health risks are reviewed and their numerous assumptions and uncertainties described. These methods involve extrapolation of risks observed at past relatively high asbestos concentration levels down to usually much lower concentration levels of interest today--in some cases, orders of magnitude lower. These models are used to calculate estimates of the potential risk to workers manufacturing asbestos products and to students enrolled in schools containing asbestos products. The potential risk to workers exposed for 40 yr to 0.5 fibers per milliliter (f/ml) of mixed asbestos fiber type (a permissible workplace exposure limit under consideration by the Occupational Safety and Health Administration (OSHA) ) are estimated as 82 lifetime excess cancers per 10,000 exposed. The risk to students exposed to an average asbestos concentration of 0.001 f/ml of mixed asbestos fiber types for an average enrollment period of 6 school years is estimated as 5 lifetime excess cancers per one million exposed. If the school exposure is to chrysotile asbestos only, then the estimated risk is 1.5 lifetime excess cancers per million. Risks from other causes are presented for comparison; e.g., annual rates (per million) of 10 deaths from high school football, 14 from bicycling (10-14 yr of age), 5 to 20 for whooping cough vaccination. Decisions concerning asbestos products require participation of all parties involved and should only be made after a scientifically defensible estimate of the associated risk has been obtained. In many cases to date, such decisions have been made without adequate consideration of the level of risk or the cost-effectiveness of attempts to lower the potential risk. 73 references.

  5. SPECIATION OF ARSENIC IN EXPOSURE ASSESSMENT MATRICES

    EPA Science Inventory

    The speciaton of arsenic in water, food and urine are analytical capabilities which are an essential part in arsenic risk assessment. The cancer risk associated with arsenic has been the driving force in generating the analytical research in each of these matrices. This presentat...

  6. Biomonitoring as a method for assessing exposure to perchlorate.

    PubMed

    Blount, Benjamin C; Valentín-Blasini, Liza

    2007-09-01

    Biomonitoring provides direct and quantitative information regarding human exposure to environmental toxicants, such as perchlorate (ClO(4)(-)). Because of concerns surrounding widespread exposure to ClO(4)(-), we are using biomonitoring methods to assess exposure to ClO(4)(-) and other physiologically relevant anions that can impact iodide uptake by the thyroid. These methods quantify ClO(4)(-), thiocyanate, nitrate, and iodide in human urine, milk, serum, blood spots, amniotic fluid, and infant formula using ion chromatography coupled with electrospray ionization tandem mass spectrometry. In this paper we summarize recent ClO(4)(-) biomonitoring research and provide three additional examples of the utility of biomonitoring for characterizing ClO(4)(-) exposure. Specifically, we examine variability in ClO(4)(-) excretion, compare the relative importance of different exposure sources in adults, and estimate ClO(4)(-) exposure in formula-fed infants. These applications provide examples of how biomonitoring can improve individual exposure assessment. Individual biomarker data can subsequently be compared with individual thyroid function data to better evaluate potential linkage between ClO(4)(-) exposure and health. PMID:17822374

  7. CAREX Canada: an enhanced model for assessing occupational carcinogen exposure

    PubMed Central

    Peters, Cheryl E; Ge, Calvin B; Hall, Amy L; Davies, Hugh W; Demers, Paul A

    2015-01-01

    Objectives To estimate the numbers of workers exposed to known and suspected occupational carcinogens in Canada, building on the methods of CARcinogen EXposure (CAREX) projects in the European Union (EU). Methods CAREX Canada consists of estimates of the prevalence and level of exposure to occupational carcinogens. CAREX Canada includes occupational agents evaluated by the International Agency for Research on Cancer as known, probable or possible human carcinogens that were present and feasible to assess in Canadian workplaces. A Canadian Workplace Exposure Database was established to identify the potential for exposure in particular industries and occupations, and to create exposure level estimates among priority agents, where possible. CAREX EU data were reviewed for relevance to the Canadian context and the proportion of workers likely to be exposed by industry and occupation in Canada was assigned using expert assessment and agreement by a minimum of two occupational hygienists. These proportions were used to generate prevalence estimates by linkage with the Census of Population for 2006, and these estimates are available by industry, occupation, sex and province. Results CAREX Canada estimated the number of workers exposed to 44 known, probable and suspected carcinogens. Estimates of levels of exposure were further developed for 18 priority agents. Common exposures included night shift work (1.9 million exposed), solar ultraviolet radiation exposure (1.5 million exposed) and diesel engine exhaust (781 000 exposed). Conclusions A substantial proportion of Canadian workers are exposed to known and suspected carcinogens at work. PMID:24969047

  8. EPHECT II: Exposure assessment to household consumer products.

    PubMed

    Dimitroulopoulou, C; Trantallidi, M; Carrer, P; Efthimiou, G C; Bartzis, J G

    2015-12-01

    Within the framework of the EPHECT project (Emissions, exposure patterns and health effects of consumer products in the EU), irritative and respiratory health effects were assessed in relation to acute and long-term exposure to key and emerging indoor air pollutants emitted during household use of selected consumer products. In this context, inhalation exposure assessment was carried out for six selected 'target' compounds (acrolein, formaldehyde, benzene, naphthalene, d-limonene and α-pinene). This paper presents the methodology and the outcomes from the micro-environmental modelling of the 'target' pollutants following single or multiple use of selected consumer products and the subsequent exposure assessment. The results indicate that emissions from consumer products of benzene and α-pinene were not considered to contribute significantly to the EU indoor background levels, in contrast to some cases of formaldehyde and d-limonene emissions in Eastern Europe (mainly from cleaning products). The group of housekeepers in East Europe appears to experience the highest exposures to acrolein, formaldehyde and benzene, followed by the group of the retired people in North, who experiences the highest exposures to naphthalene and α-pinene. High exposure may be attributed to the scenarios developed within this project, which follow a 'most-representative worst-case scenario' strategy for exposure and health risk assessment. Despite the above limitations, this is the first comprehensive study that provides exposure estimates for 8 population groups across Europe exposed to 6 priority pollutants, as a result of the use of 15 consumer product classes in households, while accounting for regional differences in uses, use scenarios and ventilation conditions of each region.

  9. EPHECT II: Exposure assessment to household consumer products.

    PubMed

    Dimitroulopoulou, C; Trantallidi, M; Carrer, P; Efthimiou, G C; Bartzis, J G

    2015-12-01

    Within the framework of the EPHECT project (Emissions, exposure patterns and health effects of consumer products in the EU), irritative and respiratory health effects were assessed in relation to acute and long-term exposure to key and emerging indoor air pollutants emitted during household use of selected consumer products. In this context, inhalation exposure assessment was carried out for six selected 'target' compounds (acrolein, formaldehyde, benzene, naphthalene, d-limonene and α-pinene). This paper presents the methodology and the outcomes from the micro-environmental modelling of the 'target' pollutants following single or multiple use of selected consumer products and the subsequent exposure assessment. The results indicate that emissions from consumer products of benzene and α-pinene were not considered to contribute significantly to the EU indoor background levels, in contrast to some cases of formaldehyde and d-limonene emissions in Eastern Europe (mainly from cleaning products). The group of housekeepers in East Europe appears to experience the highest exposures to acrolein, formaldehyde and benzene, followed by the group of the retired people in North, who experiences the highest exposures to naphthalene and α-pinene. High exposure may be attributed to the scenarios developed within this project, which follow a 'most-representative worst-case scenario' strategy for exposure and health risk assessment. Despite the above limitations, this is the first comprehensive study that provides exposure estimates for 8 population groups across Europe exposed to 6 priority pollutants, as a result of the use of 15 consumer product classes in households, while accounting for regional differences in uses, use scenarios and ventilation conditions of each region. PMID:26173853

  10. Tools for regulatory assessment of occupational exposure: development and challenges.

    PubMed

    Tielemans, Erik; Warren, Nick; Schneider, Thomas; Tischer, Martin; Ritchie, Peter; Goede, Henk; Kromhout, Hans; Van Hemmen, Joop; Cherrie, John W

    2007-12-01

    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 used with REACH. Tier 2 models, producing robust and realistic exposure assessments, are currently not available. A research programme is proposed in this paper that will result in a new, advanced exposure assessment tool for REACH. In addition, issues related to variability and uncertainty are discussed briefly, and some examples of tier 1 screening tools are presented. The proposed framework for the tier 2 tool is based on a Bayesian approach, and makes full use of mechanistically modelled estimates and any relevant measurements of exposure. The new approach will preclude the necessity to conduct of case-by-case exposure measurements for each chemical and scenario, since the system will allow for the use of analogous exposure data from relatively comparable scenarios. The development of the new approach requires substantial effort in the area of mechanistic modelling, database development and Bayesian statistical techniques. In this paper, the data gaps and areas for future research are identified to help realise and further improve this type of approach within REACH. A structured data collection and storage system is a central element of the research programme and the availability of this type of tool may also facilitate the sharing of exposure data down and up the supply chain. In addition, new data that are stored according to the proposed structure could enable the validation of any exposure model and thus this programme enhances the exposure assessment field as a whole.

  11. New Cardiovascular Risk Factors and Their Use for an Accurate Cardiovascular Risk Assessment in Hypertensive Patients

    PubMed Central

    TAUTU, Oana-Florentina; DARABONT, Roxana; ONCIUL, Sebastian; DEACONU, Alexandru; COMANESCU, Ioana; ANDREI, Radu Dan; DRAGOESCU, Bogdan; CINTEZA, Mircea; DOROBANTU, Maria

    2014-01-01

    Objectives: To analyze the predictive value of new cardiovascular (CV) risk factors for CV risk assessment in the adult Romanian hypertensive (HT) population. Methods: Hypertensive adults aged between 40-65 years of age, identified in national representative SEPHAR II survey were evaluated by anthropometric, BP and arterial stiffness measurements: aortic pulse wave velocity (PWVao), aortic augmentation index (AIXao), revers time (RT) and central systolic blood pressure (SBPao), 12 lead ECGs and laboratory workup. Values above the 4th quartile of mean SBP' standard deviation (s.d.) defined increased BP variability. Log(TG/HDL-cholesterol) defined atherogenic index of plasma (AIP). Serum uric acid levels above 5.70 mg/dl for women and 7.0 mg/dl for males defined hyperuricemia (HUA). CV risk was assessed based on SCORE chart for high CV risk countries. Binary logistic regression using a stepwise likelihood ratio method (adjustments for major confounders and colliniarity analysis) was used in order to validate predictors of high and very high CV risk class. Results: The mean SBP value of the study group was 148.46±19.61 mmHg. Over forty percent of hypertensives had a high and very high CV risk. Predictors of high/very high CV risk category validated by regression analysis were: increased visit-to-visit BP variability (OR: 2.49; 95%CI: 1.67-3.73), PWVao (OR: 1.12; 95%CI: 1.02-1.22), RT (OR: 0.95; 95% CI: 0.93-0.98), SBPao (OR: 1.01; 95%CI: 1.01-1.03) and AIP (OR: 7.08; 95%CI: 3.91-12.82). Conclusion: The results of our study suggests that the new CV risk factors such as increased BP variability, arterial stiffness indices and AIP are useful tools for a more accurate identification of hypertensives patients at high and very high CV risk. PMID:25705267

  12. A Statistical Method for Assessing Peptide Identification Confidence in Accurate Mass and Time Tag Proteomics

    SciTech Connect

    Stanley, Jeffrey R.; Adkins, Joshua N.; Slysz, Gordon W.; Monroe, Matthew E.; Purvine, Samuel O.; Karpievitch, Yuliya V.; Anderson, Gordon A.; Smith, Richard D.; Dabney, Alan R.

    2011-07-15

    High-throughput proteomics is rapidly evolving to require high mass measurement accuracy for a variety of different applications. Increased mass measurement accuracy in bottom-up proteomics specifically allows for an improved ability to distinguish and characterize detected MS features, which may in turn be identified by, e.g., matching to entries in a database for both precursor and fragmentation mass identification methods. Many tools exist with which to score the identification of peptides from LC-MS/MS measurements or to assess matches to an accurate mass and time (AMT) tag database, but these two calculations remain distinctly unrelated. Here we present a statistical method, Statistical Tools for AMT tag Confidence (STAC), which extends our previous work incorporating prior probabilities of correct sequence identification from LC-MS/MS, as well as the quality with which LC-MS features match AMT tags, to evaluate peptide identification confidence. Compared to existing tools, we are able to obtain significantly more high-confidence peptide identifications at a given false discovery rate and additionally assign confidence estimates to individual peptide identifications. Freely available software implementations of STAC are available in both command line and as a Windows graphical application.

  13. Algal productivity modeling: a step toward accurate assessments of full-scale algal cultivation.

    PubMed

    Béchet, Quentin; Chambonnière, Paul; Shilton, Andy; Guizard, Guillaume; Guieysse, Benoit

    2015-05-01

    A new biomass productivity model was parameterized for Chlorella vulgaris using short-term (<30 min) oxygen productivities from algal microcosms exposed to 6 light intensities (20-420 W/m(2)) and 6 temperatures (5-42 °C). The model was then validated against experimental biomass productivities recorded in bench-scale photobioreactors operated under 4 light intensities (30.6-74.3 W/m(2)) and 4 temperatures (10-30 °C), yielding an accuracy of ± 15% over 163 days of cultivation. This modeling approach addresses major challenges associated with the accurate prediction of algal productivity at full-scale. Firstly, while most prior modeling approaches have only considered the impact of light intensity on algal productivity, the model herein validated also accounts for the critical impact of temperature. Secondly, this study validates a theoretical approach to convert short-term oxygen productivities into long-term biomass productivities. Thirdly, the experimental methodology used has the practical advantage of only requiring one day of experimental work for complete model parameterization. The validation of this new modeling approach is therefore an important step for refining feasibility assessments of algae biotechnologies.

  14. Algal productivity modeling: a step toward accurate assessments of full-scale algal cultivation.

    PubMed

    Béchet, Quentin; Chambonnière, Paul; Shilton, Andy; Guizard, Guillaume; Guieysse, Benoit

    2015-05-01

    A new biomass productivity model was parameterized for Chlorella vulgaris using short-term (<30 min) oxygen productivities from algal microcosms exposed to 6 light intensities (20-420 W/m(2)) and 6 temperatures (5-42 °C). The model was then validated against experimental biomass productivities recorded in bench-scale photobioreactors operated under 4 light intensities (30.6-74.3 W/m(2)) and 4 temperatures (10-30 °C), yielding an accuracy of ± 15% over 163 days of cultivation. This modeling approach addresses major challenges associated with the accurate prediction of algal productivity at full-scale. Firstly, while most prior modeling approaches have only considered the impact of light intensity on algal productivity, the model herein validated also accounts for the critical impact of temperature. Secondly, this study validates a theoretical approach to convert short-term oxygen productivities into long-term biomass productivities. Thirdly, the experimental methodology used has the practical advantage of only requiring one day of experimental work for complete model parameterization. The validation of this new modeling approach is therefore an important step for refining feasibility assessments of algae biotechnologies. PMID:25502920

  15. Accurate assessment of mass, models and resolution by small-angle scattering

    PubMed Central

    Rambo, Robert P.; Tainer, John A.

    2013-01-01

    Modern small angle scattering (SAS) experiments with X-rays or neutrons provide a comprehensive, resolution-limited observation of the thermodynamic state. However, methods for evaluating mass and validating SAS based models and resolution have been inadequate. Here, we define the volume-of-correlation, Vc: a SAS invariant derived from the scattered intensities that is specific to the structural state of the particle, yet independent of concentration and the requirements of a compact, folded particle. We show Vc defines a ratio, Qr, that determines the molecular mass of proteins or RNA ranging from 10 to 1,000 kDa. Furthermore, we propose a statistically robust method for assessing model-data agreements (X2free) akin to cross-validation. Our approach prevents over-fitting of the SAS data and can be used with a newly defined metric, Rsas, for quantitative evaluation of resolution. Together, these metrics (Vc, Qr, X2free, and Rsas) provide analytical tools for unbiased and accurate macromolecular structural characterizations in solution. PMID:23619693

  16. Hypertension and Exposure to Noise near Airports (HYENA): study design and noise exposure assessment.

    PubMed

    Jarup, Lars; Dudley, Marie-Louise; Babisch, Wolfgang; Houthuijs, Danny; Swart, Wim; Pershagen, Göran; Bluhm, Gösta; Katsouyanni, Klea; Velonakis, Manolis; Cadum, Ennio; Vigna-Taglianti, Federica

    2005-11-01

    An increasing number of people live near airports with considerable noise and air pollution. The Hypertension and Exposure to Noise near Airports (HYENA) project aims to assess the impact of airport-related noise exposure on blood pressure (BP) and cardiovascular disease using a cross-sectional study design. We selected 6,000 persons (45-70 years of age) who had lived at least 5 years near one of six major European airports. We used modeled aircraft noise contours, aiming to maximize exposure contrast. Automated BP instruments are used to reduce observer error. We designed a standardized questionnaire to collect data on annoyance, noise disturbance, and major confounders. Cortisol in saliva was collected in a subsample of the study population (n = 500) stratified by noise exposure level. To investigate short-term noise effects on BP and possible effects on nighttime BP dipping, we measured 24-hr BP and assessed continuous night noise in another subsample (n = 200). To ensure comparability between countries, we used common noise models to assess individual noise exposure, with a resolution of 1 dB(A). Modifiers of individual exposure, such as the orientation of living and bedroom toward roads, window-opening habits, and sound insulation, were assessed by the questionnaire. For four airports, we estimated exposure to air pollution to explore modifying effects of air pollution on cardiovascular disease. The project assesses exposure to traffic-related air pollutants, primarily using data from another project funded by the European Union (APMoSPHERE, Air Pollution Modelling for Support to Policy on Health and Environmental Risks in Europe). PMID:16263498

  17. Near-field radiofrequency electromagnetic exposure assessment.

    PubMed

    Rubtsova, Nina; Perov, Sergey; Belaya, Olga; Kuster, Niels; Balzano, Quirino

    2015-09-01

    Personal wireless telecommunication devices, such as radiofrequency (RF) electromagnetic field (EMF) sources operated in vicinity of human body, have possible adverse health effects. Therefore, the correct EMF assessment is necessary in their near field. According to international near-field measurement criteria, the specific absorption rate (SAR) is used for absorbed energy distribution assessment in tissue simulating liquid phantoms. The aim of this investigation is to validate the relationship between the H-field of incident EMF and absorbed energy in phantoms. Three typical wireless telecommunication system frequencies are considered (900, 1800 and 2450 MHz). The EMF source at each frequency is an appropriate half-wave dipole antenna and the absorbing medium is a flat phantom filled with the suitable tissue simulating liquid. Two methods for SAR estimation have been used: standard procedure based on E-field measured in tissue simulating medium and a proposed evaluation by measuring the incident H-field. Compared SAR estimations were performed for various distances between sources and phantom. Also, these research data were compared with simulation results, obtained by using finite-difference time-domain method. The acquired data help to determine the source near-field space characterized by the smallest deviation between SAR estimation methods. So, this region near the RF source is suitable for correct RF energy absorption assessment using the magnetic component of the RF fields. PMID:26444190

  18. Near-field radiofrequency electromagnetic exposure assessment.

    PubMed

    Rubtsova, Nina; Perov, Sergey; Belaya, Olga; Kuster, Niels; Balzano, Quirino

    2015-09-01

    Personal wireless telecommunication devices, such as radiofrequency (RF) electromagnetic field (EMF) sources operated in vicinity of human body, have possible adverse health effects. Therefore, the correct EMF assessment is necessary in their near field. According to international near-field measurement criteria, the specific absorption rate (SAR) is used for absorbed energy distribution assessment in tissue simulating liquid phantoms. The aim of this investigation is to validate the relationship between the H-field of incident EMF and absorbed energy in phantoms. Three typical wireless telecommunication system frequencies are considered (900, 1800 and 2450 MHz). The EMF source at each frequency is an appropriate half-wave dipole antenna and the absorbing medium is a flat phantom filled with the suitable tissue simulating liquid. Two methods for SAR estimation have been used: standard procedure based on E-field measured in tissue simulating medium and a proposed evaluation by measuring the incident H-field. Compared SAR estimations were performed for various distances between sources and phantom. Also, these research data were compared with simulation results, obtained by using finite-difference time-domain method. The acquired data help to determine the source near-field space characterized by the smallest deviation between SAR estimation methods. So, this region near the RF source is suitable for correct RF energy absorption assessment using the magnetic component of the RF fields.

  19. Personal noise exposure assessment from small firearms

    NASA Astrophysics Data System (ADS)

    Kardous, Chucri A.; Murphy, William J.; Willson, Robert D.

    2003-04-01

    The National Institute for Occupational Safety and Health conducted noise exposure evaluations of law-enforcement personnel during firearms training at indoor and outdoor firing ranges. A representative cross section of weapons used by officers was measured. Shooters participated in live-fire exercise at an indoor firing range using three different weapons: a Beretta .400 caliber pistol, a Remington 12-gauge shotgun, and an M4 .223-caliber assault rifle. Indoor and outdoor measurements were obtained for the Smith and Wesson .357 pistol and Colt .450 and 9-mm pistols, the Glock .400 pistol, and the Heckler and Koch and Colt AR15 .223 rifles. Impulses were measured using a Bruel and Kjaer 4136 1/4-in. microphone and TASCAM digital audio tape recorder. Relevant impulse noise metrics were calculated. Peak levels ranged from 155 to 168 dB SPL. A-weighted equivalent levels ranged from 124 to 128 dBA. The contributions of the secondary weapon firings were approximately 1 to 9 dBA. Other parameters such as A/B durations, number and mixture of impulses, spectral content, energy, kurtosis, temporal spacing, and hearing protectors' effectiveness were examined. Comparisons of applicable damage risk criteria are presented. Further studies are needed to establish an occupational impulse noise damage risk criterion.

  20. TIME-INTEGRATED EXPOSURE MEASURES TO IMPROVE THE PREDICTIVE POWER OF EXPOSURE CLASSIFICATION FOR EPIDEMIOLOGIC STUDIES

    EPA Science Inventory

    Accurate exposure classification tools are required to link exposure with health effects in epidemiological studies. Although long-term integrated exposure measurements are a critical component of exposure assessment, the ability to include these measurements into epidemiologic...

  1. Mercury from dental amalgam: exposure and risk assessment.

    PubMed

    Koral, Stephen M

    2013-02-01

    There has long been an undercurrent within the dental profession of anti-amalgam sentiment, a "mercury-free" movement. To assess whether anything is or is not scientifically wrong with amalgam, one must look to the vast literature on exposure, toxicology, and risk assessment of mercury. The subject of risk assessment goes straight to the heart of the debate over whether a malgam is safe, or not, for unrestricted use in dentistry in the population at large.

  2. Assessment of potential exposure to friable insulation materials containing asbestos

    NASA Technical Reports Server (NTRS)

    Kim, W. S.; Kuivinen, D. E.

    1980-01-01

    Asbestos and the procedures for assessing potential exposure hazards are discussed. Assessment includes testing a bulk sample of the suspected material for the presence of asbestos, and monitoring the air, if necessary. Based on field inspections and laboratory analyses, the health hazard is evaluated, and abatement measures are taken if a potential hazard exists. Throughout the assessment and abatement program, all applicable regulations are administered as specified by the Environmental Protection Agency and the Occupational Safety and Health Administration.

  3. Recent advances in assessment of workplace exposure--epidemiologic linkage of medical and environmental data

    SciTech Connect

    Landrigan, P.J.

    1982-01-01

    The toxicity to man of environmental agents is most accurately assessed when quantitative data are available on both exposure (dose) and response. Worker populations are of unique importance in the study of toxic effects because they are relatively well defined, easily traced, and more heavily exposed to toxic chemical and physical agents than are members of the general community. The union of epidemiology, industrial hygiene, and occupational subacute, and chronic dose-response relationships in worker populations. This report describes the application of epidemiology to evaluations of workers exposed to methyl alcohol vapor (acute toxicity), ozone (subacute), and lead and ionizing radiation (chronic). The derivation of accurate dose-response data provides a rational basis for the establishment of exposure standards.

  4. Is photometry an accurate and reliable method to assess boar semen concentration?

    PubMed

    Camus, A; Camugli, S; Lévêque, C; Schmitt, E; Staub, C

    2011-02-01

    Sperm concentration assessment is a key point to insure appropriate sperm number per dose in species subjected to artificial insemination (AI). The aim of the present study was to evaluate the accuracy and reliability of two commercially available photometers, AccuCell™ and AccuRead™ pre-calibrated for boar semen in comparison to UltiMate™ boar version 12.3D, NucleoCounter SP100 and Thoma hemacytometer. For each type of instrument, concentration was measured on 34 boar semen samples in quadruplicate and agreement between measurements and instruments were evaluated. Accuracy for both photometers was illustrated by mean of percentage differences to the general mean. It was -0.6% and 0.5% for Accucell™ and Accuread™ respectively, no significant differences were found between instrument and mean of measurement among all equipment. Repeatability for both photometers was 1.8% and 3.2% for AccuCell™ and AccuRead™ respectively. Low differences were observed between instruments (confidence interval 3%) except when hemacytometer was used as a reference. Even though hemacytometer is considered worldwide as the gold standard, it is the more variable instrument (confidence interval 7.1%). The conclusion is that routine photometry measures of raw semen concentration are reliable, accurate and precise using AccuRead™ or AccuCell™. There are multiple steps in semen processing that can induce sperm loss and therefore increase differences between theoretical and real sperm numbers in doses. Potential biases that depend on the workflow but not on the initial photometric measure of semen concentration are discussed.

  5. Multimodal Quantitative Phase Imaging with Digital Holographic Microscopy Accurately Assesses Intestinal Inflammation and Epithelial Wound Healing.

    PubMed

    Lenz, Philipp; Brückner, Markus; Ketelhut, Steffi; Heidemann, Jan; Kemper, Björn; Bettenworth, Dominik

    2016-01-01

    The incidence of inflammatory bowel disease, i.e., Crohn's disease and Ulcerative colitis, has significantly increased over the last decade. The etiology of IBD remains unknown and current therapeutic strategies are based on the unspecific suppression of the immune system. The development of treatments that specifically target intestinal inflammation and epithelial wound healing could significantly improve management of IBD, however this requires accurate detection of inflammatory changes. Currently, potential drug candidates are usually evaluated using animal models in vivo or with cell culture based techniques in vitro. Histological examination usually requires the cells or tissues of interest to be stained, which may alter the sample characteristics and furthermore, the interpretation of findings can vary by investigator expertise. Digital holographic microscopy (DHM), based on the detection of optical path length delay, allows stain-free quantitative phase contrast imaging. This allows the results to be directly correlated with absolute biophysical parameters. We demonstrate how measurement of changes in tissue density with DHM, based on refractive index measurement, can quantify inflammatory alterations, without staining, in different layers of colonic tissue specimens from mice and humans with colitis. Additionally, we demonstrate continuous multimodal label-free monitoring of epithelial wound healing in vitro, possible using DHM through the simple automated determination of the wounded area and simultaneous determination of morphological parameters such as dry mass and layer thickness of migrating cells. In conclusion, DHM represents a valuable, novel and quantitative tool for the assessment of intestinal inflammation with absolute values for parameters possible, simplified quantification of epithelial wound healing in vitro and therefore has high potential for translational diagnostic use. PMID:27685659

  6. Precise and accurate assessment of uncertainties in model parameters from stellar interferometry. Application to stellar diameters

    NASA Astrophysics Data System (ADS)

    Lachaume, Regis; Rabus, Markus; Jordan, Andres

    2015-08-01

    In stellar interferometry, the assumption that the observables can be seen as Gaussian, independent variables is the norm. In particular, neither the optical interferometry FITS (OIFITS) format nor the most popular fitting software in the field, LITpro, offer means to specify a covariance matrix or non-Gaussian uncertainties. Interferometric observables are correlated by construct, though. Also, the calibration by an instrumental transfer function ensures that the resulting observables are not Gaussian, even if uncalibrated ones happened to be so.While analytic frameworks have been published in the past, they are cumbersome and there is no generic implementation available. We propose here a relatively simple way of dealing with correlated errors without the need to extend the OIFITS specification or making some Gaussian assumptions. By repeatedly picking at random which interferograms, which calibrator stars, and which are the errors on their diameters, and performing the data processing on the bootstrapped data, we derive a sampling of p(O), the multivariate probability density function (PDF) of the observables O. The results can be stored in a normal OIFITS file. Then, given a model m with parameters P predicting observables O = m(P), we can estimate the PDF of the model parameters f(P) = p(m(P)) by using a density estimation of the observables' PDF p.With observations repeated over different baselines, on nights several days apart, and with a significant set of calibrators systematic errors are de facto taken into account. We apply the technique to a precise and accurate assessment of stellar diameters obtained at the Very Large Telescope Interferometer with PIONIER.

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

    PubMed Central

    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

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

    PubMed

    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. PMID:25455887

  9. Advances in pesticide environmental fate and exposure assessments.

    PubMed

    Rice, Pamela J; Rice, Patricia J; Arthur, Ellen L; Barefoot, Aldos C

    2007-07-11

    Globalization of markets and the growing world population increase threats of invasive and exotic species and place greater demands on food and fiber production. Pest management in both agricultural and nonagricultural settings employs established practices and new biological, chemical, and management technologies. Pesticides are an essential tool in integrated pest management. Without pesticides a significant percentage of food and fiber crops would be lost, infectious diseases would increase, and valuable native habitats would be devastated. Therefore, it is important to understand the environmental fate of pesticides and assess their potential exposure and associated risks to human health and the environment. This paper summarizes the Advances in Pesticide Environmental Fate and Exposure Assessment symposium held at the 231st National Meeting of the American Chemical Society (Atlanta, GA, 2006). The focus of the symposium was to provide current information on advances in pesticide environmental fate and exposure assessments. Thirty papers were presented on advances ranging from subcellular processes to watershed-scale studies on topics including chemical degradation, sorption, and transport; improved methodologies; use of modeling and predictive tools; exposure assessment; and treatment and remediation. This information is necessary to develop more effective pesticide use and management practices, to better understand pesticide fate and associated exposures and risks, to develop mitigation and remediation strategies, and to establish sound science-based regulations.

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

    SciTech Connect

    Dekant, Wolfgang Voelkel, Wolfgang

    2008-04-01

    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 {mu}g/L suggesting that daily human exposure to bisphenol A is below 6 {mu}g per person (< 0.1 {mu}g/kg bw/day) for the majority of the population.

  11. Encoding negative events under stress: high subjective arousal is related to accurate emotional memory despite misinformation exposure.

    PubMed

    Hoscheidt, Siobhan M; LaBar, Kevin S; Ryan, Lee; Jacobs, W Jake; Nadel, Lynn

    2014-07-01

    Stress at encoding affects memory processes, typically enhancing, or preserving, memory for emotional information. These effects have interesting implications for eyewitness accounts, which in real-world contexts typically involve encoding an aversive event under stressful conditions followed by potential exposure to misinformation. The present study investigated memory for a negative event encoded under stress and subsequent misinformation endorsement. Healthy young adults participated in a between-groups design with three experimental sessions conducted 48 h apart. Session one consisted of a psychosocial stress induction (or control task) followed by incidental encoding of a negative slideshow. During session two, participants were asked questions about the slideshow, during which a random subgroup was exposed to misinformation. Memory for the slideshow was tested during the third session. Assessment of memory accuracy across stress and no-stress groups revealed that stress induced just prior to encoding led to significantly better memory for the slideshow overall. The classic misinformation effect was also observed - participants exposed to misinformation were significantly more likely to endorse false information during memory testing. In the stress group, however, memory accuracy and misinformation effects were moderated by arousal experienced during encoding of the negative event. Misinformed-stress group participants who reported that the negative slideshow elicited high arousal during encoding were less likely to endorse misinformation for the most aversive phase of the story. Furthermore, these individuals showed better memory for components of the aversive slideshow phase that had been directly misinformed. Results from the current study provide evidence that stress and high subjective arousal elicited by a negative event act concomitantly during encoding to enhance emotional memory such that the most aversive aspects of the event are well remembered and

  12. Exposure assessment for power frequency electric and magnetic fields.

    PubMed

    Bracken, T D

    1993-04-01

    Over the past decade considerable data have been collected on electric and magnetic fields in occupational environments. These data have taken the form of area measurements, source characterizations, and personal exposure measurements. Occupational EMF levels are highly variable in space and time. Exposures associated with these fields exhibit similar large variations during a day, between days, and between individuals within a group. The distribution of exposure measures is skewed over several decades with only a few values occurring at the maximum field levels. The skewness of exposure measures implies that large sample sizes may be required for assessments and that multiple statistical descriptors are preferred to describe individual and group exposures. Except for the relatively few occupational settings where high voltage sources are prevalent, electric fields encountered in the workplace are probably similar to residential exposures. Consequently, high electric field exposures are essentially limited to utility environments and occupations. Within the electric utility industry, it is definitely possible to identify occupations with high electric field exposures relative to those of office workers or other groups. The highly exposed utility occupations are linemen, substation operators, and utility electricians. The distribution of electric field exposures in the utility worker population is very skewed even within a given occupation. As with electric fields, magnetic fields in the workplace appear to be comparable with residential levels, unless a clearly defined high-current source is present. Since high-current sources are more prevalent than high-voltage sources, environments with relatively high magnetic field exposures encompass a more diverse set of occupations than do those with high electric fields. Within the electric utility industry, it is possible to identify occupational environments with high magnetic field exposure relative to the office

  13. FEASIBILITY OF USING THE MACROACTIVITY APPROACH TO ASSESS CHILDREN'S DERMAL EXPOSURE TO PESTICIDES

    EPA Science Inventory

    Results derived from an initial assessment of critical exposure pathways for children indicate that dermal contact may result in high residential exposures to pesticides. However, data on children's exposures and activities are insufficient to support quantitative assessments ...

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

    PubMed Central

    Setton, Eleanor M; Hystad, Perry W; Keller, C Peter

    2005-01-01

    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. PMID:16262893

  15. Work routinization and implications for ergonomic exposure assessment.

    PubMed

    Gold, Judith E; Park, Jung-Soon; Punnett, Laura

    2006-01-15

    Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels. PMID:16393801

  16. Exposure Assessment in the National Children’s Study: Introduction

    PubMed Central

    Needham, Larry L.; Özkaynak, Halûk; Whyatt, Robin M.; Barr, Dana B.; Wang, Richard Y.; Naeher, Luke; Akland, Gerry; Bahadori, Tina; Bradman, Asa; Fortmann, Roy; Liu, L-J. Sally; Morandi, Maria; O’Rourke, Mary Kay; Thomas, Kent; Quackenboss, James; Ryan, P. Barry; Zartarian, Valerie

    2005-01-01

    The science of exposure assessment is relatively new and evolving rapidly with the advancement of sophisticated methods for specific measurements at the picogram per gram level or lower in a variety of environmental and biologic matrices. Without this measurement capability, environmental health studies rely on questionnaires or other indirect means as the primary method to assess individual exposures. Although we use indirect methods, they are seldom used as stand-alone tools. Analyses of environmental and biologic samples have allowed us to get more precise data on exposure pathways, from sources to concentrations, to routes, to exposure, to doses. They also often allow a better estimation of the absorbed dose and its relation to potential adverse health outcomes in individuals and in populations. Here, we make note of various environmental agents and how best to assess exposure to them in the National Children’s Study—a longitudinal epidemiologic study of children’s health. Criteria for the analytical method of choice are discussed with particular emphasis on the need for long-term quality control and quality assurance measures. PMID:16079082

  17. Perinatal Immunotoxicity: Why Adult Exposure Assessment Fails to Predict Risk

    PubMed Central

    Dietert, Rodney R.; Piepenbrink, Michael S.

    2006-01-01

    Recent research has pointed to the developing immune system as a remarkably sensitive toxicologic target for environmental chemicals and drugs. In fact, the perinatal period before and just after birth is replete with dynamic immune changes, many of which do not occur in adults. These include not only the basic maturation and distribution of immune cell types and selection against autoreactive lymphocytes but also changes designed specifically to protect the pregnancy against immune-mediated miscarriage. The newborn is then faced with critical immune maturational adjustments to achieve an immune balance necessary to combat myriad childhood and later-life diseases. All these processes set the fetus and neonate completely apart from the adult regarding immunotoxicologic risk. Yet for decades, safety evaluation has relied almost exclusively upon exposure of the adult immune system to predict perinatal immune risk. Recent workshops and forums have suggested a benefit in employing alternative exposures that include exposure throughout early life stages. However, issues remain concerning when and where such applications might be required. In this review we discuss the reasons why immunotoxic assessment is important for current childhood diseases and why adult exposure assessment cannot predict the effect of xenobiotics on the developing immune system. It also provides examples of developmental immunotoxicants where age-based risk appears to differ. Finally, it stresses the need to replace adult exposure assessment for immune evaluation with protocols that can protect the developing immune system. PMID:16581533

  18. Work routinization and implications for ergonomic exposure assessment.

    PubMed

    Gold, Judith E; Park, Jung-Soon; Punnett, Laura

    2006-01-15

    Jobs in many modern settings, including manufacturing, service, agriculture and construction, are variable in their content and timing. This prompts the need for exposure assessment methods that do not assume regular work cycles. A scheme is presented for classifying levels of routinization to inform development of an appropriate exposure assessment strategy for a given occupational setting. Five levels of routinization have been defined based on the tasks of which the job is composed: 1) a single scheduled task with a regular work cycle; 2) multiple cyclical tasks; 3) a mix of cyclical and non-cyclical tasks; 4) one non-cyclical task; 5) multiple non-cyclical tasks. This classification, based primarily on job observation, is illustrated through data from a study of automobile manufacturing workers (n = 1200), from which self-assessed exposures to physical and psychosocial stressors were also obtained. In this cohort, decision latitude was greater with higher routinization level (p < 0.0001), and the least routinized jobs showed the lowest self-reported exposure to physical ergonomic stressors. The job analysis checklist developed for non-routinized jobs is presented, and limitations of the task analysis method utilized in the study are discussed. A work sampling approach to job analysis is recommended as the most efficient way to obtain a comparable unbiased exposure estimate across all routinization levels.

  19. Skin exposure: Assessing the hazard in the workplace

    NASA Technical Reports Server (NTRS)

    Cummins, Kevin

    1994-01-01

    An outline of the Occupational Safety and Health Agency's concerns of skin exposure to hazardous chemicals is presented, followed by the corresponding slide narrations. Specifically, dermatitis and skin absorption as compared to lung absorption are addressed. Lung versus skin exposure is examined for glycol ethers and acrylamide. Examples of skin exposure include PBC's in transformers, toluene and xylene from autobody work, polynuclear aromatics (PNA's) among Coke oven workers, toluene diisocyanate (TDI), and occupational chemical exposures in an academic medical center. Permeation through gloves in the semiconductor industry is addressed as evidence for the need to assess the effectiveness of PPE (Personal Protective Equipment). This leads to the revisions of the PPE standard and the Safety and Health Program standard.

  20. European consumer exposure to cosmetic products, a framework for conducting population exposure assessments.

    PubMed

    Hall, B; Tozer, S; Safford, B; Coroama, M; Steiling, W; Leneveu-Duchemin, M C; McNamara, C; Gibney, M

    2007-11-01

    Access to reliable exposure data is essential to evaluate the toxicological safety of ingredients in cosmetic products. This study was carried out by European cosmetic manufacturers acting within the trade association Colipa, with the aim to construct a probabilistic European population model of exposure. The study updates, in distribution form, the current exposure data on daily quantities of six cosmetic products. Data were collected using a combination of market information databases and a controlled product use study. In total 44,100 households and 18,057 individual consumers in five European countries provided data using their own products. All product use occasions were recorded, including those outside of home. The raw data were analysed using Monte Carlo simulation and a European Statistical Population Model of exposure was constructed. A significant finding was an inverse correlation between frequency of product use and quantity used per application for body lotion, facial moisturiser, toothpaste and shampoo. Thus it is not appropriate to calculate daily exposure to these products by multiplying the maximum frequency value by the maximum quantity per event value. The results largely confirm the exposure parameters currently used by the cosmetic industry. Design of this study could serve as a model for future assessments of population exposure to chemicals in products other than cosmetics.

  1. The Penobscot River and environmental contaminants: Assessment of tribal exposure through sustenance lifeways

    USGS Publications Warehouse

    Marshall, Valerie; Kusnierz, Daniel; Hillger, Robert; Ferrario, Joseph; Hughes, Thomas; Diliberto, Janet; Orazio, Carl E.; Dudley, Robert W.; Byrne, Christian; Sugatt, Richard; Warren, Sarah; DeMarini, David; Elskus, Adria; Stodola, Steve; Mierzykowski, Steve; Pugh, Katie; Culbertson, Charles W.

    2015-01-01

    . The objectives of this Regional Applied Research Effort (RARE) study were to: Develop culturally sensitive methodologies for assessing the potential level of exposure tocontaminants that Penobscot Indian Nation tribal members may have from maintainingtribal sustenance practices. Conduct field surveys and laboratory analysis on targeted flora and fauna for chemicalexposure to dioxins/furans, polychlorinated biphenyls (PCBs), total mercury and methyl-mercury. Assist the Agency for Toxic Substances and Disease Registry (ATSDR) by providing thenecessary data to conduct a Public Health Assessment for the Penobscot Indian Nation. Establish protocols for assessing the level of exposure to PCBs, dioxins/furans and mercuryto PIN tribal members as a consequence of gathering tribal plants for medicinal andnutritional purposes; as well as consuming fish, wood duck, and snapping turtle as a primarysource of nutrition. Survey surface water, drinking water, and sediment from the Penobscot River and IndianIsland to assess the exposure of PIN tribal members to environmental genotoxicants thatcontinue cultural sustenance practices. This research initiative collected and analyzed sediment and biota to determine the level of contaminant exposure to Penobscot tribal members. Natural resource utilization patterns and exposure pathways were identified based on discussions with the Tribal elders. Identification of Tribal exposure factors (exposure pathways and contaminant concentrations) was essential for accurately assessing potential long-term Penobscot Indian Nation tribal members’ exposure. Based on this study, ATSDR’s Public Health Assessment (PHA) concluded that the Penobscot Indian Nation (PIN) tribal members who eat fish and snapping turtle at the ingestion levels suggested in the Wabanaki Traditional Cultural Lifeways Exposure Scenario Report (Wabanaki Exposure Scenario) may be exposed to harmful levels of mercury, dioxins/furans, dioxin-like PCBs, and ot

  2. Carbon nanotube dosimetry: from workplace exposure assessment to inhalation toxicology

    PubMed Central

    2013-01-01

    Background Dosimetry for toxicology studies involving carbon nanotubes (CNT) is challenging because of a lack of detailed occupational exposure assessments. Therefore, exposure assessment findings, measuring the mass concentration of elemental carbon from personal breathing zone (PBZ) samples, from 8 U.S.-based multi-walled CNT (MWCNT) manufacturers and users were extrapolated to results of an inhalation study in mice. Results Upon analysis, an inhalable elemental carbon mass concentration arithmetic mean of 10.6 μg/m3 (geometric mean 4.21 μg/m3) was found among workers exposed to MWCNT. The concentration equates to a deposited dose of approximately 4.07 μg/d in a human, equivalent to 2 ng/d in the mouse. For MWCNT inhalation, mice were exposed for 19 d with daily depositions of 1970 ng (equivalent to 1000 d of a human exposure; cumulative 76 yr), 197 ng (100 d; 7.6 yr), and 19.7 ng (10 d; 0.76 yr) and harvested at 0, 3, 28, and 84 d post-exposure to assess pulmonary toxicity. The high dose showed cytotoxicity and inflammation that persisted through 84 d after exposure. The middle dose had no polymorphonuclear cell influx with transient cytotoxicity. The low dose was associated with a low grade inflammatory response measured by changes in mRNA expression. Increased inflammatory proteins were present in the lavage fluid at the high and middle dose through 28 d post-exposure. Pathology, including epithelial hyperplasia and peribronchiolar inflammation, was only noted at the high dose. Conclusion These findings showed a limited pulmonary inflammatory potential of MWCNT at levels corresponding to the average inhalable elemental carbon concentrations observed in U.S.-based CNT facilities and estimates suggest considerable years of exposure are necessary for significant pathology to occur at that level. PMID:24144386

  3. Exposure Assessments and Toxicology in the 21st Century

    EPA Science Inventory

    It is widely recognized that the hazard and dose response portions of chemical risk assessments are being transformed by the availability of Adverse Outcome Pathways (AOPs) and in vitro and in silico data on biological activity. This transformation is also changing the exposure a...

  4. PRELIMINARY EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY

    EPA Science Inventory

    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. EXPOSURE ASSESSMENT FINDINGS FROM THE TAMPA ASTHMATIC CHILDREN'S STUDY (TACS)

    EPA Science Inventory

    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...

  6. An Exposure Assessment of Polybrominated Diphenyl Ethers (Pbde) (Final)

    EPA Science Inventory

    Cover of the PBDE Final Report This final report provides a comprehensive assessment of the exposure of Americans to this class of persistent ...

  7. DERMAL EXPOSURE ASSESSMENT: A SUMMARY OF EPA APPROACHES

    EPA Science Inventory

    This final report presents a concise description and evaluation of the approaches used in the Agency for dermal exposure assessment including a discussion about harmonization and research needs in this area. The report is intended to be used by EPA program offices in their effort...

  8. USE OF MACROACTIVITY APPROACH TO ASSESS DERMAL EXPOSURE

    EPA Science Inventory

    Currently, data on children's exposures and activities are very limited and insufficient to support quantitative assessments that do not rely heavily on major default assumptions as substitutes for missing information (Cohen Hubal et al. 2000a, b). Cohen Hubal et al. (2000a, b...

  9. A New Model for Environmental Assessment and Exposure Reduction

    PubMed Central

    Ciaccio, Christina E.; Kennedy, Kevin; Portnoy, Jay M.

    2012-01-01

    Environmental assessment and exposure reduction are a set of diagnostic and treatment techniques that work in tandem with the traditional medical approach by reducing a patient’s exposure to adverse environmental conditions as part of medical care. Assessment involves identifying the specific exposures to which a patient is sensitive and locating the corresponding contaminants in the patient’s environment. This provides a more complete diagnostic evaluation of a patient’s problem than could be obtained merely by examining the patient alone. Exposure reduction involves reducing the identified triggers to levels that are below thresholds that are associated with increased risk of sensitization and disease morbidity. Assessment of an environment for contaminants focuses on a chain of factors that include contaminant sources such as cockroaches, rodents, dust mites and fungi that excrete contaminants into an environment, facilitative factors such as moisture, food, water and shelter that help sources to thrive, and reservoirs where contaminants can accumulate prior to subsequent transport to occupants. By using this model to guide environmental assessments and their corresponding interventions, the root cause of health problems can be addressed, leading to improved quality of life for patients and reduced need for chronic medications. PMID:22933137

  10. Role of Metabolomics in Environmental Chemical Exposure and Risk Assessment

    EPA Science Inventory

    The increasing demand for the reduction, replacement, and refinement of the use of animal models in exposure assessments has stimulated the pursuit of alternative methods. This has included not only the use of the in vitro systems (e.g., cell cultures) in lieu of in vivo whole an...

  11. EXPOSURE ASSESSMENT IN THE NATIONAL CHILDREN'S STUDY-INTRODUCTION

    EPA Science Inventory

    The science of exposure assessment is relatively new and evolving rapidly with the advancement of sophisticated methods for specific measurements at the picogram per gram level or lower in a variety of environmental and biologic matrices. Without this measurement capability, envi...

  12. APPLICATION OF METABOLOMICS FOR IMPROVING ECOLOGICAL EXPOSURE AND RISK ASSESSMENTS

    EPA Science Inventory

    We have developed a research program in metabolomics that involves numerous partners across EPA, other federal labs, academia, and the private sector. A primary goal is to develop metabolite-based markers that can be used by EPA in ecological exposure and risk assessments. We are...

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

    SciTech Connect

    Callahan, M.A.

    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. Sulfur Oxides Risk and Exposure Assessment Planning Document

    EPA Science Inventory

    In conducting risk/exposure assessments for the Sulfur Oxides NAAQS review, EPA will first develop a draft Scope and Methods Plan which will describe the proposed scope of the quantitative and qualitative analyses to be performed and the tools/methods that may be employed

  15. Data analysis techniques: a tool for cumulative exposure assessment.

    PubMed

    Lalloué, Benoît; Monnez, Jean-Marie; Padilla, Cindy; Kihal, Wahida; Zmirou-Navier, Denis; Deguen, Séverine

    2015-01-01

    Everyone is subject to environmental exposures from various sources, with negative health impacts (air, water and soil contamination, noise, etc.or with positive effects (e.g. green space). Studies considering such complex environmental settings in a global manner are rare. We propose to use statistical factor and cluster analyses to create a composite exposure index with a data-driven approach, in view to assess the environmental burden experienced by populations. We illustrate this approach in a large French metropolitan area. The study was carried out in the Great Lyon area (France, 1.2 M inhabitants) at the census Block Group (BG) scale. We used as environmental indicators ambient air NO2 annual concentrations, noise levels and proximity to green spaces, to industrial plants, to polluted sites and to road traffic. They were synthesized using Multiple Factor Analysis (MFA), a data-driven technique without a priori modeling, followed by a Hierarchical Clustering to create BG classes. The first components of the MFA explained, respectively, 30, 14, 11 and 9% of the total variance. Clustering in five classes group: (1) a particular type of large BGs without population; (2) BGs of green residential areas, with less negative exposures than average; (3) BGs of residential areas near midtown; (4) BGs close to industries; and (5) midtown urban BGs, with higher negative exposures than average and less green spaces. Other numbers of classes were tested in order to assess a variety of clustering. We present an approach using statistical factor and cluster analyses techniques, which seem overlooked to assess cumulative exposure in complex environmental settings. Although it cannot be applied directly for risk or health effect assessment, the resulting index can help to identify hot spots of cumulative exposure, to prioritize urban policies or to compare the environmental burden across study areas in an epidemiological framework.

  16. Assessing exposure to allied ground troops in the Vietnam War: a quantitative evaluation of the Stellman Exposure Opportunity Index model.

    PubMed

    Ginevan, Michael E; Watkins, Deborah K; Ross, John H; O'Boyle, Randy A

    2009-06-01

    The Exposure Opportunity Index (EOI) is a proximity-based model developed to estimate relative exposure of ground troops in Vietnam to aerially applied herbicides. We conducted a detailed quantitative evaluation of the EOI model by using actual herbicide spray missions isolated in time and space. EOI scores were calculated for each of 36 hypothetical receptor location points associated with each spray mission for 30 herbicide missions for two time periods - day of herbicide application and day 2-3 post-application. Our analysis found an enormous range of EOI predictions with 500-1000-fold differences across missions directly under the flight path. This quantitative examination of the EOI suggests that extensive testing of the model's code is warranted. Researchers undertaking development of a proximity-based exposure model for epidemiologic studies of either Vietnam veterans or the Vietnamese population should conduct a thorough and realistic analysis of how precise and accurate the model results are likely to be and then assess whether the model results provide a useful basis for their planned epidemiologic studies.

  17. Assessing exposure to allied ground troops in the Vietnam War: a quantitative evaluation of the Stellman Exposure Opportunity Index model.

    PubMed

    Ginevan, Michael E; Watkins, Deborah K; Ross, John H; O'Boyle, Randy A

    2009-06-01

    The Exposure Opportunity Index (EOI) is a proximity-based model developed to estimate relative exposure of ground troops in Vietnam to aerially applied herbicides. We conducted a detailed quantitative evaluation of the EOI model by using actual herbicide spray missions isolated in time and space. EOI scores were calculated for each of 36 hypothetical receptor location points associated with each spray mission for 30 herbicide missions for two time periods - day of herbicide application and day 2-3 post-application. Our analysis found an enormous range of EOI predictions with 500-1000-fold differences across missions directly under the flight path. This quantitative examination of the EOI suggests that extensive testing of the model's code is warranted. Researchers undertaking development of a proximity-based exposure model for epidemiologic studies of either Vietnam veterans or the Vietnamese population should conduct a thorough and realistic analysis of how precise and accurate the model results are likely to be and then assess whether the model results provide a useful basis for their planned epidemiologic studies. PMID:19278712

  18. Exposure assessment of particulate matter for susceptible populations in Seattle.

    PubMed Central

    Liu, L-J Sally; Box, Michael; Kalman, David; Kaufman, Joel; Koenig, Jane; Larson, Tim; Lumley, Thomas; Sheppard, Lianne; Wallace, Lance

    2003-01-01

    In this article we present results from a 2-year comprehensive exposure assessment study that examined the particulate matter (PM) exposures and health effects in 108 individuals with and without chronic obstructive pulmonary disease (COPD), coronary heart disease (CHD), and asthma. The average personal exposures to PM with aerodynamic diameters < 2.5 microm (PM2.5) were similar to the average outdoor PM2.5 concentrations but significantly higher than the average indoor concentrations. Personal PM2.5 exposures in our study groups were lower than those reported in other panel studies of susceptible populations. Indoor and outdoor PM2.5, PM10 (PM with aerodynamic diameters < 10 microm), and the ratio of PM2.5 to PM10 were significantly higher during the heating season. The increase in outdoor PM10 in winter was primarily due to an increase in the PM2.5 fraction. A similar seasonal variation was found for personal PM2.5. The high-risk subjects in our study engaged in an equal amount of dust-generating activities compared with the healthy elderly subjects. The children in the study experienced the highest indoor PM2.5 and PM10 concentrations. Personal PM2.5 exposures varied by study group, with elderly healthy and CHD subjects having the lowest exposures and asthmatic children having the highest exposures. Within study groups, the PM2.5 exposure varied depending on residence because of different particle infiltration efficiencies. Although we found a wide range of longitudinal correlations between central-site and personal PM2.5 measurements, the longitudinal r is closely related to the particle infiltration efficiency. PM2.5 exposures among the COPD and CHD subjects can be predicted with relatively good power with a microenvironmental model composed of three microenvironments. The prediction power is the lowest for the asthmatic children. PMID:12782491

  19. Reading Assessment Methods for Middle-School Students: An Investigation of Reading Comprehension Rate and Maze Accurate Response Rate

    ERIC Educational Resources Information Center

    Hale, Andrea D.; Henning, Jaime B.; Hawkins, Renee O.; Sheeley, Wesley; Shoemaker, Larissa; Reynolds, Jennifer R.; Moch, Christina

    2011-01-01

    This study was designed to investigate the validity of four different aloud reading comprehension assessment measures: Maze, comprehension questions, Maze accurate response rate (MARR), and reading comprehension rate (RCR). The criterion measures used in this study were the Woodcock-Johnson III Tests of Achievement (WJ-III ACH) Broad Reading…

  20. Retrospective exposure assessment to airborne asbestos among power industry workers

    PubMed Central

    2010-01-01

    Background A method of individually assessing former exposure to asbestos fibres is a precondition of risk-differentiated health surveillance. The main aims of our study were to assess former levels of airborne asbestos exposure in the power industry in Germany and to propose a basic strategy for health surveillance and the early detection of asbestos related diseases. Methods Between March 2002 and the end of 2006, we conducted a retrospective questionnaire based survey of occupational tasks and exposures with airborne asbestos fibres in a cohort of 8632 formerly asbestos exposed power industry workers. The data on exposure and occupation were entered into a specially designed computer programme, based on ambient monitoring of airborne asbestos fibre concentrations. The cumulative asbestos exposure was expressed as the product of the eight-hour time weighted average and the total duration of exposure in fibre years (fibres/cubic centimetre-years). Results Data of 7775 (90% of the total) participants working in installations for power generation, power distribution or gas supply could be evaluated. The power generation group (n = 5284) had a mean age of 56 years, were exposed for 20 years and had an average cumulative asbestos exposure of 42 fibre years. The occupational group of "metalworkers" (n = 1600) had the highest mean value of 79 fibre years. The corresponding results for the power distribution group (n = 2491) were a mean age of 45 years, a mean exposure duration of 12 years and an average cumulative asbestos exposure of only 2.5 fibre years. The gas supply workers (n = 512) had a mean age of 54 years and a mean duration of exposure of 15 years. Conclusions While the surveyed cohort as a whole was heavily exposed to asbestos dust, the power distribution group had a mean cumulative exposure of only 6% of that found in the power generation group. Based on the presented data, risk-differentiated disease surveillance focusing on metalworkers and electricians

  1. A New Model for Biological Dose Assessment in Cases of Heterogeneous Exposures to Ionizing Radiation.

    PubMed

    Pujol, Mònica; Barrios, Leonardo; Puig, Pedro; Caballín, María Rosa; Barquinero, Joan-Francesc

    2016-02-01

    In biological dosimetry by dicentric analysis, an exposure to radiation is considered non-homogeneous if the dicentric cell distribution shows overdispersion with respect to Poisson distribution. Traditionally, when this occurs, all non-homogeneous exposures are considered as partial-body exposures, assuming that there is only a mixture of irradiated and nonirradiated cells. The methods to estimate the dose in the irradiated fraction and the initial fraction of irradiated cells are based on separating which part of the cells without aberrations comes from the nonirradiated or irradiated fractions. In this study we show a new approach based on a mixed Poisson model, which allows for a distinction to be made between partial and heterogeneous exposures. To validate this approach blood samples from two donors, a male and a female, irradiated at different doses, were mixed at a 1:1 proportion to simulate partial and heterogeneous exposures. The results show a good agreement between the observed proportion of male and female cells and the proportion estimated by the model. Additionally, a good agreement was observed between the delivered doses, the initial fraction of cells and the ones estimated by the model. This good agreement was also observed after very high-dose irradiation (up to 17 Gy), when the lymphocyte cultures were treated with caffeine. Based on these results, we propose the use of this mixed Poisson model for a more accurate assessment of non-homogeneous exposures.

  2. Linkage of the California Pesticide Use Reporting Database with Spatial Land Use Data for Exposure Assessment

    PubMed Central

    Nuckols, John R.; Gunier, Robert B.; Riggs, Philip; Miller, Ryan; Reynolds, Peggy; Ward, Mary H.

    2007-01-01

    Background The State of California maintains a comprehensive Pesticide Use Reporting Database (CPUR). The California Department of Water Resources (CDWR) maps all crops in agricultural counties in California about once every 5 years. Objective We integrated crop maps with CPUR to more accurately locate where pesticides are applied and evaluated the effects for exposure assessment. Methods We mapped 577 residences and used the CPUR and CDWR data to compute two exposure metrics based on putative pesticide use within a 500-m buffer. For the CPUR metric, we assigned pesticide exposure to the residence proportionally for all square-mile Sections that intersected the buffer. For the CDWR metric, we linked CPUR crop-specific pesticide use to crops mapped within the buffer and assigned pesticide exposure. We compared the metrics for six pesticides: simazine, trifluralin (herbicides), dicofol, propargite (insecticides), methyl bromide, and metam sodium (fumigants). Results For all six pesticides we found good agreement (88–98%) as to whether the pesticide use was predicted. When we restricted the analysis to residences with reported pesticide use in Sections within 500 m, agreement was greatly reduced (35–58%). The CPUR metric estimates of pesticide use within 500 m were significantly higher than the CDWR metric for all six pesticides. Conclusions Our findings may have important implications for exposure classification in epidemiologic studies of agricultural pesticide use using CPUR. There is a need to conduct environmental and biological measurements to ascertain which, if any, of these metrics best represent exposure. PMID:17520053

  3. A New Model for Biological Dose Assessment in Cases of Heterogeneous Exposures to Ionizing Radiation.

    PubMed

    Pujol, Mònica; Barrios, Leonardo; Puig, Pedro; Caballín, María Rosa; Barquinero, Joan-Francesc

    2016-02-01

    In biological dosimetry by dicentric analysis, an exposure to radiation is considered non-homogeneous if the dicentric cell distribution shows overdispersion with respect to Poisson distribution. Traditionally, when this occurs, all non-homogeneous exposures are considered as partial-body exposures, assuming that there is only a mixture of irradiated and nonirradiated cells. The methods to estimate the dose in the irradiated fraction and the initial fraction of irradiated cells are based on separating which part of the cells without aberrations comes from the nonirradiated or irradiated fractions. In this study we show a new approach based on a mixed Poisson model, which allows for a distinction to be made between partial and heterogeneous exposures. To validate this approach blood samples from two donors, a male and a female, irradiated at different doses, were mixed at a 1:1 proportion to simulate partial and heterogeneous exposures. The results show a good agreement between the observed proportion of male and female cells and the proportion estimated by the model. Additionally, a good agreement was observed between the delivered doses, the initial fraction of cells and the ones estimated by the model. This good agreement was also observed after very high-dose irradiation (up to 17 Gy), when the lymphocyte cultures were treated with caffeine. Based on these results, we propose the use of this mixed Poisson model for a more accurate assessment of non-homogeneous exposures. PMID:26771173

  4. NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY (NHEXAS): ANALYSIS OF EXPOSURE PATHWAYS AND ROUTES FOR ARSENIC AND LEAD IN EPA REGION 5

    EPA Science Inventory

    The National Human Exposure Assessment Survey (NHEXAS) Phase I field study conducted in EPA Region 5 (Great Lakes Area) provides extensive exposure data on a representative sample of approximately 250 residents of the region. Associated environmental media and biomarker (blood...

  5. Exposure assessment of MWCNTs in their life cycle

    NASA Astrophysics Data System (ADS)

    Ono-Ogasawara, M.; Takaya, M.; Yamada, M.

    2015-05-01

    Multi-walled carbon nanotubes (MWCNTs) are used as a filler in composites to obtain electrical conductivity, and improve mechanical strength and other properties. However, exposure to MWCNTs may pose health risks because of their size, shape, and insolubility. A quantitative exposure assessment method for CNTs is therefore needed. We have developed a promising carbon analysis method that considers the size distribution of elemental carbon. We conducted exposure assessment according to the lifecycle of CNTs. At the first stage, large quantity of CNTs are handled and exposure to neat CNTs is likely to occur. When large quantity of CNTs are handled, enclosure and automated process are strongly recommended. By applying appropriate measures, CNT concentration can be well controlled. Local exhaust ventilation and less-restrictive enclosures were found to work well during the second stage, which involves handling smaller CNT quantities. At measured sites, MWCNT concentrations were below an occupational exposure level proposed by Nakanishi (i.e., 0.030 mg/m3). This analysis method can also be applied to particles containing MWCNTs. At downstream stages of the lifecycle, neat MWCNTs were not observed and concentrations of embedded MWCNTs were lower than 0.015 mg/m3.

  6. Environmental exposure assessment framework for nanoparticles in solid waste.

    PubMed

    Boldrin, Alessio; Hansen, Steffen Foss; Baun, Anders; Hartmann, Nanna Isabella Bloch; Astrup, Thomas Fruergaard

    2014-01-01

    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.

  7. Advances in Inhalation Dosimetry Models and Methods for Occupational Risk Assessment and Exposure Limit Derivation

    PubMed Central

    Kuempel, Eileen D.; Sweeney, Lisa M.; Morris, John B.; Jarabek, Annie M.

    2015-01-01

    The purpose of this article is to provide an overview and practical guide to occupational health professionals concerning the derivation and use of dose estimates in risk assessment for development of occupational exposure limits (OELs) for inhaled substances. Dosimetry is the study and practice of measuring or estimating the internal dose of a substance in individuals or a population. Dosimetry thus provides an essential link to understanding the relationship between an external exposure and a biological response. Use of dosimetry principles and tools can improve the accuracy of risk assessment, and reduce the uncertainty, by providing reliable estimates of the internal dose at the target tissue. This is accomplished through specific measurement data or predictive models, when available, or the use of basic dosimetry principles for broad classes of materials. Accurate dose estimation is essential not only for dose-response assessment, but also for interspecies extrapolation and for risk characterization at given exposures. Inhalation dosimetry is the focus of this paper since it is a major route of exposure in the workplace. Practical examples of dose estimation and OEL derivation are provided for inhaled gases and particulates. PMID:26551218

  8. Assessing radiation exposure during endoscopic-guided percutaneous nephrolithotomy

    PubMed Central

    Lantz, Andrea G.; O’Malley, Padraic; Ordon, Michael; Lee, Jason Y.

    2014-01-01

    Introduction: Percutaneous nephrolithotomy (PCNL) may be associated with significant ionizing radiation exposure for patients and operating room staff. Endoscopic-guided PCNL (ePCNL) is a technique that may be associated with less radiation exposure. This study examines ePCNL-related radiation exposure (fluoroscopy time, effective dose) and investigates variables that may predict increased exposure. Methods: A retrospective review of all consecutive ePCNLs performed at our institution, by a single surgeon, was conducted between November 2011 and November 2013. Patient demographics, stone characteristics and perioperative details were recorded, including radiation exposure. Pearson and Spearman correlation were used to assess variables correlated with radiation exposure. Results: In total, 55 ePCNL cases were included in the study. The mean age was 60 ± 15 years, mean body mass index (BMI) 30.0 ± 6.4 kg/m2 and mean stone size 3.2 × 2.1 cm. Seven cases (13%) involved complete staghorn stones, and 69% involved supracostal punctures. The mean fluoroscopy time was 3.4 ± 2.3 minutes, mean ED 2.4 ± 1.9 mSv. The treatment success rate, assessed 1-week postoperatively, was 87.3% and 7.3% of cases required ancillary procedures. The overall complication rate was 29%, but only 3 cases (5.5%) were Clavien ≥3. Longer fluoroscopy time correlated with increased stone size (p < 0.01), longer operative time (p < 0.01) and lower treatment success rates (p < 0.01); higher effective dose correlated with longer fluoroscopy time (p < 0.01) and increased skin-to-stone distance (p < 0.01). BMI did not correlate with fluoroscopy time or effective dose. Conclusions: Outcomes of ePCNL are comparable to traditional PCNL techniques and may be associated with lower radiation exposure, particularly beneficial for patients with higher BMI. PMID:25408802

  9. [Risk assessment of human exposure to pesticides in food].

    PubMed

    Knežević, Zorka; Serdar, Maja

    2011-09-01

    This review presents methods for the assessment of acute and chronic risk from pesticide residues in food. Multiple pesticide residues can often be found in food. Currently, there is no internationally accepted procedure for the assessment of cumulative exposure to multiple pesticide residues in food. Therefore, risk assessment is based on toxicological evaluation of single compounds in a food matrix. The international estimation of short-term intake model (IESTI) has been used to calculate acute intake. IESTI is based on "the worst-case scenario" and addresses the possibility that consumers sometimes eat large amounts of a food item, and such a large amount might contain residues at highest levels. However, it should take into account uneven distribution of pesticide residues in food. Chronic exposure is based on a deterministic approach, analogous to the calculation of the theoretical maximum daily intake.

  10. Human health risk assessment from arsenic exposures in Bangladesh.

    PubMed

    Joseph, Tijo; Dubey, Brajesh; McBean, Edward A

    2015-09-15

    High arsenic exposures, prevalent through dietary and non-dietary sources in Bangladesh, present a major health risk to the public. A quantitative human health risk assessment is described as a result of arsenic exposure through food and water intake, tea intake, accidental soil ingestion, and chewing of betel quid, while people meet their desirable dietary intake requirements throughout their lifetime. In evaluating the contribution of each intake pathway to average daily arsenic intake, the results show that food and water intake combined, makes up approximately 98% of the daily arsenic intake with the balance contributed to by intake pathways such as tea consumption, soil ingestion, and quid consumption. Under an exposure scenario where arsenic concentration in water is at the WHO guideline (0.01 mg/L), food intake is the major arsenic intake pathway ranging from 67% to 80% of the average daily arsenic intake. However, the contribution from food drops to a range of 29% to 45% for an exposure scenario where arsenic in water is at the Bangladesh standard (0.05 mg/L). The lifetime excess risk of cancer occurrence from chronic arsenic exposure, considering a population of 160 million people, based on an exposure scenario with 85 million people at the WHO guideline value and 75 million people at the Bangladesh standard, and assuming that 35 million people are associated with a heavy activity level, is estimated as 1.15 million cases.

  11. Assessing the reproductive health of men with occupational exposures.

    PubMed

    Schrader, Steven M; Marlow, Katherine L

    2014-01-01

    The earliest report linking environmental (occupational) exposure to adverse human male reproductive effects dates back to1775 when an English physician, Percival Pott, reported a high incidence of scrotal cancer in chimney sweeps. This observation led to safety regulations in the form of bathing requirements for these workers. The fact that male-mediated reproductive harm in humans may be a result of toxicant exposures did not become firmly established until relatively recently, when Lancranjan studied lead-exposed workers in Romania in 1975, and later in 1977, when Whorton examined the effects of dibromochloropropane (DBCP) on male workers in California. Since these discoveries, several additional human reproductive toxicants have been identified through the convergence of laboratory and observational findings. Many research gaps remain, as the pool of potential human exposures with undetermined effects on male reproduction is vast. This review provides an overview of methods used to study the effects of exposures on male reproduction and their reproductive health, with a primary emphasis on the implementation and interpretation of human studies. Emphasis will be on occupational exposures, although much of the information is also useful in assessing environmental studies, occupational exposures are usually much higher and better defined.

  12. Assessing the reproductive health of men with occupational exposures

    PubMed Central

    Schrader, Steven M; Marlow, Katherine L

    2014-01-01

    The earliest report linking environmental (occupational) exposure to adverse human male reproductive effects dates back to1775 when an English physician, Percival Pott, reported a high incidence of scrotal cancer in chimney sweeps. This observation led to safety regulations in the form of bathing requirements for these workers. The fact that male-mediated reproductive harm in humans may be a result of toxicant exposures did not become firmly established until relatively recently, when Lancranjan studied lead-exposed workers in Romania in 1975, and later in 1977, when Whorton examined the effects of dibromochloropropane (DBCP) on male workers in California. Since these discoveries, several additional human reproductive toxicants have been identified through the convergence of laboratory and observational findings. Many research gaps remain, as the pool of potential human exposures with undetermined effects on male reproduction is vast. This review provides an overview of methods used to study the effects of exposures on male reproduction and their reproductive health, with a primary emphasis on the implementation and interpretation of human studies. Emphasis will be on occupational exposures, although much of the information is also useful in assessing environmental studies, occupational exposures are usually much higher and better defined. PMID:24369130

  13. A new assessment method of outdoor tobacco smoke (OTS) exposure

    NASA Astrophysics Data System (ADS)

    Cho, Hyeri; Lee, Kiyoung

    2014-04-01

    Outdoor tobacco smoke (OTS) is concerned due to potential health effects. An assessment method of OTS exposure is needed to determine effects of OTS and validate outdoor smoking policies. The objective of this study was to develop a new method to assess OTS exposure. This study was conducted at 100 bus stops including 50 centerline bus stops and 50 roadside bus stops in Seoul, Korea. Using real-time aerosol monitor, PM2.5 was measured for 30 min at each bus stop in two seasons. ‘Peak analysis' method was developed to assess short term PM2.5 exposure by OTS. The 30-min average PM2.5 exposure at each bus stop was associated with season and bus stop location but not smoking activity. The PM2.5 peak occurrence rate by the peak analysis method was significantly associated with season, bus stop location, observed smoking occurrence, and the number of buses servicing a route. The PM2.5 peak concentration was significantly associated with season, smoking occurrence, and the number of buses servicing a route. When a smoker was standing still at the bus stop, magnitude of peak concentrations were significantly higher than when the smoker walking-through the bus stop. People were exposed to high short-term PM2.5 peak levels at bus stops, and the magnitude of peak concentrations were highest when a smoker was located close to the monitor. The magnitude of peak concentration was a good indicator helped distinguish nearby OTS exposure. Further research using ‘peak analysis' is needed to measure smoking-related exposure to PM2.5 in other outdoor locations.

  14. Occupational exposure assessment: Practices in Malaysian nuclear agency

    NASA Astrophysics Data System (ADS)

    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).

  15. Simplified pregnant woman models for the fetus exposure assessment

    NASA Astrophysics Data System (ADS)

    Jala, Marjorie; Conil, Emmanuelle; Varsier, Nadège; Wiart, Joe; Hadjem, Abdelhamid; Moulines, Éric; Lévy-Leduc, Céline

    2013-05-01

    In this paper, we introduce a study that we carried out in order to validate the use of a simplified pregnant woman model for the assessment of the fetus exposure to radio frequency waves. This simplified model, based on the use of a homogeneous tissue to replace most of the inner organs of the virtual mother, would allow us to deal with many issues that are raised because of the lack of pregnant woman models for numerical dosimetry. Using specific absorption rate comparisons, we show that this model could be used to estimate the fetus exposure to plane waves.

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

    NASA Technical Reports Server (NTRS)

    Atwell, William; Weyland, Mark D.; Hardy, Alva C.

    1991-01-01

    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.

  17. How accurate and precise are limited sampling strategies in estimating exposure to mycophenolic acid in people with autoimmune disease?

    PubMed

    Abd Rahman, Azrin N; Tett, Susan E; Staatz, Christine E

    2014-03-01

    Mycophenolic acid (MPA) is a potent immunosuppressant agent, which is increasingly being used in the treatment of patients with various autoimmune diseases. Dosing to achieve a specific target MPA area under the concentration-time curve from 0 to 12 h post-dose (AUC12) is likely to lead to better treatment outcomes in patients with autoimmune disease than a standard fixed-dose strategy. This review summarizes the available published data around concentration monitoring strategies for MPA in patients with autoimmune disease and examines the accuracy and precision of methods reported to date using limited concentration-time points to estimate MPA AUC12. A total of 13 studies were identified that assessed the correlation between single time points and MPA AUC12 and/or examined the predictive performance of limited sampling strategies in estimating MPA AUC12. The majority of studies investigated mycophenolate mofetil (MMF) rather than the enteric-coated mycophenolate sodium (EC-MPS) formulation of MPA. Correlations between MPA trough concentrations and MPA AUC12 estimated by full concentration-time profiling ranged from 0.13 to 0.94 across ten studies, with the highest associations (r (2) = 0.90-0.94) observed in lupus nephritis patients. Correlations were generally higher in autoimmune disease patients compared with renal allograft recipients and higher after MMF compared with EC-MPS intake. Four studies investigated use of a limited sampling strategy to predict MPA AUC12 determined by full concentration-time profiling. Three studies used a limited sampling strategy consisting of a maximum combination of three sampling time points with the latest sample drawn 3-6 h after MMF intake, whereas the remaining study tested all combinations of sampling times. MPA AUC12 was best predicted when three samples were taken at pre-dose and at 1 and 3 h post-dose with a mean bias and imprecision of 0.8 and 22.6 % for multiple linear regression analysis and of -5.5 and 23.0 % for

  18. 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

    PubMed Central

    2011-01-01

    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 < 0.0001) than estimates

  19. A statistical method for assessing peptide identification confidence in accurate mass and time tag proteomics.

    PubMed

    Stanley, Jeffrey R; Adkins, Joshua N; Slysz, Gordon W; Monroe, Matthew E; Purvine, Samuel O; Karpievitch, Yuliya V; Anderson, Gordon A; Smith, Richard D; Dabney, Alan R

    2011-08-15

    Current algorithms for quantifying peptide identification confidence in the accurate mass and time (AMT) tag approach assume that the AMT tags themselves have been correctly identified. However, there is uncertainty in the identification of AMT tags, because this is based on matching LC-MS/MS fragmentation spectra to peptide sequences. In this paper, we incorporate confidence measures for the AMT tag identifications into the calculation of probabilities for correct matches to an AMT tag database, resulting in a more accurate overall measure of identification confidence for the AMT tag approach. The method is referenced as Statistical Tools for AMT Tag Confidence (STAC). STAC additionally provides a uniqueness probability (UP) to help distinguish between multiple matches to an AMT tag and a method to calculate an overall false discovery rate (FDR). STAC is freely available for download, as both a command line and a Windows graphical application.

  20. The effect of manipulated and accurate assessment feedback on the self-efficacy of dance students.

    PubMed

    García-Dantas, Ana; Quested, Eleanor

    2015-03-01

    Research undertaken with athletes has shown that lower-evaluated feedback is related to low self-efficacy levels. However, the relationship between teacher feedback and self-efficacy has not been studied in the dance setting. In sports or dance contexts, very few studies have manipulated feedback content to examine its impact on performers' self-efficacy in relation to the execution of a specific movement. Therefore, the aim of this investigation was to explore the effect of manipulated upper, lower, and accurate grade feedback on changes in dancers' self-efficacy levels for the execution of the "Zapateado" (a flamenco foot movement). Sixty-one students (56 female, 5 male, ages 13 to 22 ± 3.25 years) from a Spanish dance conservatory participated in this experimental study. They were randomly divided into four feedback groups: 1. upper-evaluated, 2. objective and informational, 3. lower-evaluated, and 4. no feedback-control. Participants performed three trials during a 1-hour session and completed questionnaires tapping self-efficacy pre-feedback and post-feedback. After each trial, teachers (who were confederates in the study) were first asked to rate their perception of each dancer's competence level at performing the movement according to conventional criteria (scores from 0 to 10). The results were then manipulated, and students accurate, lower-evaluated, or upper-evaluated scores were given. Those in the accurate feedback group reported positive change in self-efficacy, whereas those in the lower-evaluated group showed no significant change in self-efficacy during the course of the trial. Findings call into question the common perception among teachers that it can be motivating to provide students with inaccurate feedback that indicates that the students' performance level is much better or much worse than they actually perceive it to be. Self-efficacy appears most likely to increase in students when feedback is accurate. PMID:25741781

  1. The effect of manipulated and accurate assessment feedback on the self-efficacy of dance students.

    PubMed

    García-Dantas, Ana; Quested, Eleanor

    2015-03-01

    Research undertaken with athletes has shown that lower-evaluated feedback is related to low self-efficacy levels. However, the relationship between teacher feedback and self-efficacy has not been studied in the dance setting. In sports or dance contexts, very few studies have manipulated feedback content to examine its impact on performers' self-efficacy in relation to the execution of a specific movement. Therefore, the aim of this investigation was to explore the effect of manipulated upper, lower, and accurate grade feedback on changes in dancers' self-efficacy levels for the execution of the "Zapateado" (a flamenco foot movement). Sixty-one students (56 female, 5 male, ages 13 to 22 ± 3.25 years) from a Spanish dance conservatory participated in this experimental study. They were randomly divided into four feedback groups: 1. upper-evaluated, 2. objective and informational, 3. lower-evaluated, and 4. no feedback-control. Participants performed three trials during a 1-hour session and completed questionnaires tapping self-efficacy pre-feedback and post-feedback. After each trial, teachers (who were confederates in the study) were first asked to rate their perception of each dancer's competence level at performing the movement according to conventional criteria (scores from 0 to 10). The results were then manipulated, and students accurate, lower-evaluated, or upper-evaluated scores were given. Those in the accurate feedback group reported positive change in self-efficacy, whereas those in the lower-evaluated group showed no significant change in self-efficacy during the course of the trial. Findings call into question the common perception among teachers that it can be motivating to provide students with inaccurate feedback that indicates that the students' performance level is much better or much worse than they actually perceive it to be. Self-efficacy appears most likely to increase in students when feedback is accurate.

  2. Pollution exposure on marine protected areas: A global assessment.

    PubMed

    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. PMID:26330016

  3. Pollution exposure on marine protected areas: A global assessment.

    PubMed

    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.

  4. SPECT-OPT multimodal imaging enables accurate evaluation of radiotracers for β-cell mass assessments

    PubMed Central

    Eter, Wael A.; Parween, Saba; Joosten, Lieke; Frielink, Cathelijne; Eriksson, Maria; Brom, Maarten; Ahlgren, Ulf; Gotthardt, Martin

    2016-01-01

    Single Photon Emission Computed Tomography (SPECT) has become a promising experimental approach to monitor changes in β-cell mass (BCM) during diabetes progression. SPECT imaging of pancreatic islets is most commonly cross-validated by stereological analysis of histological pancreatic sections after insulin staining. Typically, stereological methods do not accurately determine the total β-cell volume, which is inconvenient when correlating total pancreatic tracer uptake with BCM. Alternative methods are therefore warranted to cross-validate β-cell imaging using radiotracers. In this study, we introduce multimodal SPECT - optical projection tomography (OPT) imaging as an accurate approach to cross-validate radionuclide-based imaging of β-cells. Uptake of a promising radiotracer for β-cell imaging by SPECT, 111In-exendin-3, was measured by ex vivo-SPECT and cross evaluated by 3D quantitative OPT imaging as well as with histology within healthy and alloxan-treated Brown Norway rat pancreata. SPECT signal was in excellent linear correlation with OPT data as compared to histology. While histological determination of islet spatial distribution was challenging, SPECT and OPT revealed similar distribution patterns of 111In-exendin-3 and insulin positive β-cell volumes between different pancreatic lobes, both visually and quantitatively. We propose ex vivo SPECT-OPT multimodal imaging as a highly accurate strategy for validating the performance of β-cell radiotracers. PMID:27080529

  5. Assessing total exposures to gasoline vapor using the source exposure model.

    PubMed

    Edgerton, S A; Shah, J J

    1992-01-01

    Recent developments in source apportionment modeling of volatile organic compounds (VOCs) include receptor modeling (RM) applications to "total" (indoor and outdoor) exposure assessment for source of VOC. Source fingerprints are available for major VOC sources such as gasoline vapor, automobile exhaust, refinery emissions, cleaning solvent vapors, printing inks, and waste-water treatment facilities. The relative proportion of each VOC species in the source fingerprint enables the RM method, through a least squares analysis, to identify each source's presence and quantify its contribution to ambient air concentrations. Sampling periods and locations may be selected to represent microenvironmental exposures. Receptor modeling has direct applicability to determining the relative contribution of gasoline vapors to VOC exposures in the general population.

  6. Assessing total exposures to gasoline vapor using the source exposure model.

    PubMed

    Edgerton, S A; Shah, J J

    1992-01-01

    Recent developments in source apportionment modeling of volatile organic compounds (VOCs) include receptor modeling (RM) applications to "total" (indoor and outdoor) exposure assessment for source of VOC. Source fingerprints are available for major VOC sources such as gasoline vapor, automobile exhaust, refinery emissions, cleaning solvent vapors, printing inks, and waste-water treatment facilities. The relative proportion of each VOC species in the source fingerprint enables the RM method, through a least squares analysis, to identify each source's presence and quantify its contribution to ambient air concentrations. Sampling periods and locations may be selected to represent microenvironmental exposures. Receptor modeling has direct applicability to determining the relative contribution of gasoline vapors to VOC exposures in the general population. PMID:1504631

  7. Assessment of radio frequency exposures in schools, homes, and public places in Belgium.

    PubMed

    Verloock, Leen; Joseph, Wout; Goeminne, Francis; Martens, Luc; Verlaek, Mart; Constandt, Kim

    2014-12-01

    Characterization of exposure from emerging radio frequency (RF) technologies in areas where children are present is important. Exposure to RF electromagnetic fields (EMF) was assessed in three "sensitive" microenvironments; namely, schools, homes, and public places located in urban environments and compared to exposure in offices. In situ assessment was conducted by performing spatial broadband and accurate narrowband measurements, providing 6-min averaged electric-field strengths. A distinction between internal (transmitters that are located indoors) and external (outdoor sources from broadcasting and telecommunication) sources was made. Ninety-four percent of the broadband measurements were below 1 V m(-1). The average and maximal total electric-field values in schools, homes, and public places were 0.2 and 3.2 V m(-1) (WiFi), 0.1 and 1.1 V m(-1) (telecommunication), and 0.6 and 2.4 V m(-1) (telecommunication), respectively, while for offices, average and maximal exposure were 0.9 and 3.3 V m(-1) (telecommunication), satisfying the ICNIRP reference levels. In the schools considered, the highest maximal and average field values were due to internal signals (WiFi). In the homes, public places, and offices considered, the highest maximal and average field values originated from telecommunication signals. Lowest exposures were obtained in homes. Internal sources contributed on average more indoors (31.2%) than outdoors (2.3%), while the average contributions of external sources (broadcast and telecommunication sources) were higher outdoors (97.7%) than at indoor positions (68.8%). FM, GSM, and UMTS dominate the total downlink exposure in the outdoor measurements. In indoor measurements, FM, GSM, and WiFi dominate the total exposure. The average contribution of the emerging technology LTE was only 0.6%. PMID:25353235

  8. Assessment of radio frequency exposures in schools, homes, and public places in Belgium.

    PubMed

    Verloock, Leen; Joseph, Wout; Goeminne, Francis; Martens, Luc; Verlaek, Mart; Constandt, Kim

    2014-12-01

    Characterization of exposure from emerging radio frequency (RF) technologies in areas where children are present is important. Exposure to RF electromagnetic fields (EMF) was assessed in three "sensitive" microenvironments; namely, schools, homes, and public places located in urban environments and compared to exposure in offices. In situ assessment was conducted by performing spatial broadband and accurate narrowband measurements, providing 6-min averaged electric-field strengths. A distinction between internal (transmitters that are located indoors) and external (outdoor sources from broadcasting and telecommunication) sources was made. Ninety-four percent of the broadband measurements were below 1 V m(-1). The average and maximal total electric-field values in schools, homes, and public places were 0.2 and 3.2 V m(-1) (WiFi), 0.1 and 1.1 V m(-1) (telecommunication), and 0.6 and 2.4 V m(-1) (telecommunication), respectively, while for offices, average and maximal exposure were 0.9 and 3.3 V m(-1) (telecommunication), satisfying the ICNIRP reference levels. In the schools considered, the highest maximal and average field values were due to internal signals (WiFi). In the homes, public places, and offices considered, the highest maximal and average field values originated from telecommunication signals. Lowest exposures were obtained in homes. Internal sources contributed on average more indoors (31.2%) than outdoors (2.3%), while the average contributions of external sources (broadcast and telecommunication sources) were higher outdoors (97.7%) than at indoor positions (68.8%). FM, GSM, and UMTS dominate the total downlink exposure in the outdoor measurements. In indoor measurements, FM, GSM, and WiFi dominate the total exposure. The average contribution of the emerging technology LTE was only 0.6%.

  9. Contribution of locally grown foods in cumulative exposure assessments.

    PubMed

    Lobscheid, Agnes B; Maddalena, Randy L; McKone, Thomas E

    2004-01-01

    Both laboratory and field studies confirm the importance of vegetation for scavenging semivolatile organic chemicals (SVOCs) from the atmosphere and a number of exposure studies have found that the dietary pathway is often a significant contributor to cumulative exposure for these chemicals. However, little information exists on the atmospheric source-to-dietary intake linkage for SVOCs. Because of higher SVOC emissions to urban regions, this linkage is particularly important for foods that are grown, distributed and consumed in or near urban regions. The food pathway can also contribute to dietary exposure for populations that are remote from a pollutant source if the pollutants can migrate to agricultural regions and subsequently to the agricultural commodities distributed to that population. We use available data, the characteristic travel distance, and the CalTOX multimedia model framework to assess the contribution of local sources of food to cumulative SVOC intake. Based on published concentration data for foods, our exposure calculations indicate that the potential intake through ingestion can be up to 1000 times that of inhalation for certain persistent SVOCs. We use the population-based intake fraction (iF) to determine how SVOC intake can vary among food commodities and exposure pathways, and to determine the contribution of airborne emitted SVOCs to the diet in the Northern Hemisphere. We focus on three representative multimedia SVOCs-benzo(a)pyrene, fluoranthene, and 2,3,7,8-tetrachlorodibenzo-p-dioxin. The approach presented here provides a useful framework and starting point for source-to-intake assessments for the ambient air-to-dietary exposure pathway.

  10. Assessment of global flood exposures - developing an appropriate approach

    NASA Astrophysics Data System (ADS)

    Millinship, Ian; Booth, Naomi

    2015-04-01

    Increasingly complex probabilistic catastrophe models have become the standard for quantitative flood risk assessments by re/insurance companies. On the one hand, probabilistic modelling of this nature is extremely useful; a large range of risk metrics can be output. However, they can be time consuming and computationally expensive to develop and run. Levels of uncertainty are persistently high despite, or perhaps because of, attempts to increase resolution and complexity. A cycle of dependency between modelling companies and re/insurers has developed whereby available models are purchased, models run, and both portfolio and model data 'improved' every year. This can lead to potential exposures in perils and territories that are not currently modelled being largely overlooked by companies, who may then face substantial and unexpected losses when large events occur in these areas. We present here an approach to assessing global flood exposures which reduces the scale and complexity of approach used and begins with the identification of hotspots where there is a significant exposure to flood risk. The method comprises four stages: i) compile consistent exposure information, ii) to apply reinsurance terms and conditions to calculate values exposed, iii) to assess the potential hazard using a global set of flood hazard maps, and iv) to identify potential risk 'hotspots' which include considerations of spatially and/or temporally clustered historical events, and local flood defences. This global exposure assessment is designed as a scoping exercise, and reveals areas or cities where the potential for accumulated loss is of significant interest to a reinsurance company, and for which there is no existing catastrophe model. These regions are then candidates for the development of deterministic scenarios, or probabilistic models. The key advantages of this approach will be discussed. These include simplicity and ability of business leaders to understand results, as well as

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

    SciTech Connect

    Janeen Denise Robertson

    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.

  12. Risk Assessment of Radiation Exposure using Molecular Biodosimetry

    NASA Technical Reports Server (NTRS)

    Elliott, Todd F.; George, K.; Hammond, D. K.; Cucinotta, F. A.

    2007-01-01

    Current cytogenetic biodosimetry methods would be difficult to adapt to spaceflight operations, because they require toxic chemicals and a substantial amount of time to perform. In addition, current biodosimetry techniques are limited to whole body doses over about 10cGy. Development of new techniques that assess radiation exposure response at the molecular level could overcome these limitations and have important implications in the advancement of biodosimetry. Recent technical advances include expression profiling at the transcript and protein level to assess multiple biomarkers of exposure, which may lead to the development of a radiation biomarker panel revealing possible fingerprints of individual radiation sensitivity. So far, many biomarkers of interest have been examined in their response to ionizing radiation, such as cytokines and members of the DNA repair pathway. New technology, such as the Luminex system can analyze many biomarkers simultaneously in one sample.

  13. How to Achieve Accurate Peer Assessment for High Value Written Assignments in a Senior Undergraduate Course

    ERIC Educational Resources Information Center

    Jeffery, Daniel; Yankulov, Krassimir; Crerar, Alison; Ritchie, Kerry

    2016-01-01

    The psychometric measures of accuracy, reliability and validity of peer assessment are critical qualities for its use as a supplement to instructor grading. In this study, we seek to determine which factors related to peer review are the most influential on these psychometric measures, with a primary focus on the accuracy of peer assessment or how…

  14. Using transportation demand models to assess regional noise exposure

    NASA Astrophysics Data System (ADS)

    Kaliski, Kenneth

    2005-09-01

    In the United States, most metropolitan areas run some type of transportation demand model to estimate regional travel patterns, and, to some extent, air pollution. The more advanced of these models accurately represent the geographic contours of the roadways (in contrast to the older straight-line node and link models). This allows an almost seamless integration of these new transportation demand models into noise prediction models. Combined with the locations of individual homes from a separate E911 database, we can readily make estimates of the noise exposure of populations over large areas. In this paper, the regional traffic noise exposure of residences of Chittenden County, VT is estimated and mapped. It was found that 30% of the residences are exposed to noise levels exceeding the WHO sleep disturbance level of 45 dB LAeq(8) and 20% of residences are exposed to levels exceeding the WHO ``serious annoyance'' level of 55 dB LAeq(16). Maps show noise contours as well as individual homes color coded based on relative day and night noise exposure levels. Measured sound level data are given for particular locations to validate the predictions.

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

    PubMed

    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.

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

    PubMed Central

    Lesmes Fabian, Camilo; Binder, Claudia R.

    2015-01-01

    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. PMID:25938911

  17. Human exposure assessment and the National Toxicology Program.

    PubMed Central

    Lucier, G W; Schecter, A

    1998-01-01

    The National Institute of Environmental Health Sciences/National Toxicology Program (NIEHS/NTP) is developing a new interagency initiative in exposure assessment. This initiative involves the NIEHS, the Centers for Disease Control and Prevention through its National Center for Environmental Health, the National Institute for Occupational Safety and Health, the EPA, and other participating institutes and agencies of the NTP. This initiative will benefit public health and priority setting in a number of ways. First, as discussed above, it will strengthen the scientific foundation for risk assessments by the development of more credible exposure/response relationships in people by improving cross-species extrapolation, the development of biologically based dose-response models, and the identification of sensitive subpopulations and for "margin of exposure" based estimates of risk. Second, it will provide the kind of information necessary for deciding which chemicals should be studied with the limited resources available for toxicological testing. For example, there are 85,000 chemicals in commerce today, and the NTP can only provide toxicological evaluations on 10-20 per year. Third, we would use the information obtained from the exposure initiative to focus our research on mixtures that are actually present in people's bodies. Fourth, we would obtain information on the kinds and amount of chemicals in children and other potentially sensitive subpopulations. Determinations of whether additional safety factors need to be applied to children must rest, in part, upon comparative exposure analyses between children and adults. Fifth, this initiative, taken together with the environmental genome initiative, will provide the science base essential for meaningful studies on gene/environment interactions, particularly for strengthening the evaluation of epidemiology studies. Sixth, efficacy of public health policies aimed at reducing human exposure to chemical agents could be

  18. TRIAGE DOSE ASSESSMENT FOR PARTIAL-BODY EXPOSURE: DICENTRIC ANALYSIS

    PubMed Central

    Moroni, Maria; Pellmar, Terry C.

    2009-01-01

    Partial-body biodosimetry is likely to be required after a radiological or nuclear exposure. Clinical signs and symptoms, distribution of dicentrics in circulating blood cells, organ-specific biomarkers, physical signals in teeth and nails all can provide indications of non-homogeneous exposures. Organ specific biomarkers may provide early warning regarding physiological systems at risk after radiation injury. Use of a combination of markers and symptoms will be needed for clinical insights for therapeutic approaches. Analysis of dicentrics, a marker specific for radiation injury, is the “Gold standard” of biodosimetry and can reveal partial-body exposures. Automation of sample processing for dicentric analysis can increase throughput with customization of off-the-shelf technologies for cytogenetic sample processing and information management. Automated analysis of the metaphase spreads is currently limited but improvements are in development. Our efforts bridge the technological gaps to allow the use of dicentric chromosome assay (DCA) for risk-based stratification of mass casualties. This article summarizes current knowledge on partial-body cytogenetic dose assessment synthesizing information leading to the proposal of an approach to triage dose prediction in radiation mass casualties, based on equivalent whole-body doses under partial-body exposure conditions and assesses the validity of using this model. An initial screening using only 20 metaphase spreads per subject can confirm irradiation above 2-Gy. A subsequent increase to 50 metaphases improves dose determination to allow risk stratification for clinical triage. Metaphases evaluated for inhomogeneous distribution of dicentrics can reveal partial-body exposures. We tested the validity of this approach in an in vitro model that simulates partial-body irradiation by mixing irradiated and un-irradiated lymphocytes in various proportions. Our preliminary results support the notion that this approach will

  19. Self- and peer assessment may not be an accurate measure of PBL tutorial process

    PubMed Central

    Machado, José Lúcio Martins; Machado, Valéria Menezes Peixeiro; Grec, Waldir; Bollela, Valdes Roberto; Vieira, Joaquim Edson

    2008-01-01

    Background Universidade Cidade de São Paulo adopted a problem-based learning (PBL) strategy as the predominant method for teaching and learning medicine. Self-, peer- and tutor marks of the educational process are taken into account as part of the final grade, which also includes assessment of content. This study compared the different perspectives (and grades) of evaluators during tutorials with first year medical students, from 2004 to 2007 (n = 349), from seven semesters. Methods The tutorial evaluation method was comprised of the students' self assessment (SA) (10%), tutor assessment (TA) (80%) and peer assessment (PA) (10%) to calculate a final educational process grade for each tutorial. We compared these three grades from each tutorial for seven semesters using ANOVA and a post hoc test. Results A total of 349 students participated with 199 (57%) women and 150 (42%) men. The SA and PA scores were consistently greater than the TA scores. Moreover, the SA and PA groups did not show statistical difference in any semester evaluated, while both differed from tutor assessment in all semesters (Kruskal-Wallis, Dunn's test). The Spearman rank order showed significant (p < 0.0001) and positive correlation for the SA and PA groups (r = 0.806); this was not observed when we compared TA with PA (r = 0.456) or TA with SA (r = 0.376). Conclusion Peer- and self-assessment marks might be reliable but not valid for PBL tutorial process, especially if these assessments are used for summative assessment, composing the final grade. This article suggests reconsideration of the use of summative assessment for self-evaluation in PBL tutorials. PMID:19038048

  20. AN OVERVIEW OF PATHOGEN RESEARCH IN THE MICROBIOLOGICAL AND CHEMICAL EXPOSURE ASSESSMENT RESEARCH DIVISION

    EPA Science Inventory

    The Microbiological and Chemical Exposure Assessment Research Division of the EPA Office of Research and Development's National Exposure Research Laboratory has a robust in-house research program aimed at developing better occurrence and exposure methods for waterborne pathogens....

  1. Assessment of a Pesticide Exposure Intensity Algorithm in the Agricultural Health Study

    EPA Science Inventory

    The accuracy of the exposure assessment is a critical factor in epidemiological investigations of pesticide exposures and health in agricultural populations. However, few studies have been conducted to evaluate questionnaire-based exposure metrics. The Agricultural Health Study...

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

    SciTech Connect

    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

  3. A correlative imaging based methodology for accurate quantitative assessment of bone formation in additive manufactured implants.

    PubMed

    Geng, Hua; Todd, Naomi M; Devlin-Mullin, Aine; Poologasundarampillai, Gowsihan; Kim, Taek Bo; Madi, Kamel; Cartmell, Sarah; Mitchell, Christopher A; Jones, Julian R; Lee, Peter D

    2016-06-01

    A correlative imaging methodology was developed to accurately quantify bone formation in the complex lattice structure of additive manufactured implants. Micro computed tomography (μCT) and histomorphometry were combined, integrating the best features from both, while demonstrating the limitations of each imaging modality. This semi-automatic methodology registered each modality using a coarse graining technique to speed the registration of 2D histology sections to high resolution 3D μCT datasets. Once registered, histomorphometric qualitative and quantitative bone descriptors were directly correlated to 3D quantitative bone descriptors, such as bone ingrowth and bone contact. The correlative imaging allowed the significant volumetric shrinkage of histology sections to be quantified for the first time (~15 %). This technique demonstrated the importance of location of the histological section, demonstrating that up to a 30 % offset can be introduced. The results were used to quantitatively demonstrate the effectiveness of 3D printed titanium lattice implants.

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

    PubMed

    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. PMID:25863314

  5. Assessment of human exposure to copper: a case study using the NHEXAS database.

    PubMed

    Georgopoulos, Panos G; Wang, Sheng Wei; Georgopoulos, Ioannis G; Yonone-Lioy, Mary Jean; Lioy, Paul J

    2006-09-01

    Copper is an essential trace element and adverse health effects can potentially be associated with both very low and very high intakes. Accurate estimates of inhalation and ingestion (food and drinking water) exposures are therefore needed in order to realistically assess any effects of the distribution of copper intakes within the general population. The work presented here demonstrates an application of a customized subset of the MENTOR/SHEDS-4M computational system (Modeling ENvironment for TOtal Risk studies, employing the Stochastic Human Exposure and Dose Simulation approach, for Multimedia, Multipathway, Multiroute exposures to Multiple co-occurring contaminants. The application utilized data from the National Human Exposure Assessment Survey (NHEXAS) for USEPA Region V as well as from a variety of other available databases. The case study, using a statistical population-based modeling framework, was performed for Eaton County, MI. The results of the simulations, aggregated for six age subgroups of the general population, suggest that food intake is the major pathway for total copper exposure, while drinking water can have significant contributions at the tail of the distribution of intakes. Specifically, it was estimated that over 80% of the county population received potential doses of copper from food that were lower than the Institute of Medicine (IOM) Recommended Dietary Allowance (RDA) value of 900 microg/day. Furthermore, the total combined potential dose from food and water was only about two times greater than the recommended value only for individuals with intakes in the range above the 99th percentile of both food and water intakes. The values were well below the upper tolerable intake value of 10,000 microg/day. The inhalation route consistently acted as only a minor contributor to the total exposure. PMID:16249795

  6. Cross-shift changes in FEV1 in relation to wood dust exposure: the implications of different exposure assessment methods

    PubMed Central

    Schlunssen, V; Sigsgaard, T; Schaumburg, I; Kromhout, H

    2004-01-01

    Background: Exposure-response analyses in occupational studies rely on the ability to distinguish workers with regard to exposures of interest. Aims: To evaluate different estimates of current average exposure in an exposure-response analysis on dust exposure and cross-shift decline in FEV1 among woodworkers. Methods: Personal dust samples (n = 2181) as well as data on lung function parameters were available for 1560 woodworkers from 54 furniture industries. The exposure to wood dust for each worker was calculated in eight different ways using individual measurements, group based exposure estimates, a weighted estimate of individual and group based exposure estimates, and predicted values from mixed models. Exposure-response relations on cross-shift changes in FEV1 and exposure estimates were explored. Results: A positive exposure-response relation between average dust exposure and cross-shift FEV1 was shown for non-smokers only and appeared to be most pronounced among pine workers. In general, the highest slope and standard error (SE) was revealed for grouping by a combination of task and factory size, the lowest slope and SE was revealed for estimates based on individual measurements, with the weighted estimate and the predicted values in between. Grouping by quintiles of average exposure for task and factory combinations revealed low slopes and high SE, despite a high contrast. Conclusion: For non-smokers, average dust exposure and cross-shift FEV1 were associated in an exposure dependent manner, especially among pine workers. This study confirms the consequences of using different exposure assessment strategies studying exposure-response relations. It is possible to optimise exposure assessment combining information from individual and group based exposure estimates, for instance by applying predicted values from mixed effects models. PMID:15377768

  7. Assessment of children`s long-term exposure to magnetic fields (The Geomet study). Final report

    SciTech Connect

    Koontz, M.D.; Koontz, M.D.; Mehegan, L.L.; Dietrich, F.M.; Nagda, N.L.

    1992-11-01

    Past epidemiologic studies have had conflicting results concerning a possible association between childhood cancer and magnetic field exposure, perhaps because indirect measures of exposure were used. This pilot study was conducted to assess day-today and seasonal variations in children`s exposure, the contributions of different environments to total exposure, and the level of measurement/observational detail needed to accurately predict or classify children`s exposures. Twenty-eight children in two age groups (8 to 11 years and under 4 years) were personally monitored for exposure to magnetic fields. All subjects were monitored for two consecutive days during winter or spring, and 12 of the subjects were monitored during both seasons. Surrogates for exposure were developed from observation of wiring configurations, indoor/outdoor spot measurements of field strength, and continuous stationary monitoring at selected indoor locations in parallel with personal monitoring. The results indicate that a single monitoring episode may be insufficient for characterization of long-term exposure, and spot measurements at one point in time may not be adequate to predict exposure. For this study, wire codes and measures based on parallel stationary monitoring in the child`s bedroom were the best surrogates for personal exposure.

  8. Assessment of relative potential for Legionella species or surrogates inhalation exposure from common water uses.

    PubMed

    Hines, Stephanie A; Chappie, Daniel J; Lordo, Robert A; Miller, Brian D; Janke, Robert J; Lindquist, H Alan; Fox, Kim R; Ernst, Hiba S; Taft, Sarah C

    2014-06-01

    The Legionella species have been identified as important waterborne pathogens in terms of disease morbidity and mortality. Microbial exposure assessment is a tool that can be utilized to assess the potential of Legionella species inhalation exposure from common water uses. The screening-level exposure assessment presented in this paper developed emission factors to model aerosolization, quantitatively assessed inhalation exposures of aerosolized Legionella species or Legionella species surrogates while evaluating two generalized levels of assumed water concentrations, and developed a relative ranking of six common in-home uses of water for potential Legionella species inhalation exposure. Considerable variability in the calculated exposure dose was identified between the six identified exposure pathways, with the doses differing by over five orders of magnitude in each of the evaluated exposure scenarios. The assessment of exposure pathways that have been epidemiologically associated with legionellosis transmission (ultrasonic and cool mist humidifiers) produced higher estimated inhalation exposure doses than pathways where epidemiological evidence of transmission has been less strong (faucet and shower) or absent (toilets and therapy pool). With consideration of the large uncertainties inherent in the exposure assessment process used, a relative ranking of exposure pathways from highest to lowest exposure doses was produced using culture-based measurement data and the assumption of constant water concentration across exposure pathways. In this ranking, the ultrasonic and cool mist humidifier exposure pathways were estimated to produce the highest exposure doses, followed by the shower and faucet exposure pathways, and then the toilet and therapy pool exposure pathways.

  9. Biomonitoring and Biomarkers: Exposure Assessment Will Never Be the Same

    PubMed Central

    Paustenbach, Dennis; Galbraith, David

    2006-01-01

    Using modern analytical technology, it is now possible to measure almost any chemical present in our bodies. The future role of classical exposure assessment will perhaps be marginalized because biomonitoring programs can directly measure the concentration of chemicals that are present in biologic matrices. Although the concentration of chemicals in the environment will continue to be measured and related to exposure parameters, the prioritization of the national environmental agenda will be dictated by biomonitoring. Recent biomonitoring studies have examined the levels of > 200 chemicals. Biomonitoring data, by themselves, are not informative in helping consumers understand their individual health risk. A major challenge facing those who conduct biomonitoring programs is how to best communicate the information to the public. In this article, we review benefits and challenges, along with select results from the Centers for Disease Control and Prevention’s 2005 National Report on Human Exposure to Environmental Chemicals. We recommend that these data be carefully interpreted, with the goal of establishing baseline exposure information, rather than creating surrogates for conclusions about human health risk. PMID:16882516

  10. Biomonitoring and biomarkers: exposure assessment will never be the same.

    PubMed

    Paustenbach, Dennis; Galbraith, David

    2006-08-01

    Using modern analytical technology, it is now possible to measure almost any chemical present in our bodies. The future role of classical exposure assessment will perhaps be marginalized because biomonitoring programs can directly measure the concentration of chemicals that are present in biologic matrices. Although the concentration of chemicals in the environment will continue to be measured and related to exposure parameters, the prioritization of the national environmental agenda will be dictated by biomonitoring. Recent biomonitoring studies have examined the levels of >200 chemicals. Biomonitoring data, by themselves, are not informative in helping consumers understand their individual health risk. A major challenge facing those who conduct biomonitoring programs is how to best communicate the information to the public. In this article, we review benefits and challenges, along with select results from the Centers for Disease Control and Prevention's 2005 National Report on Human Exposure to Environmental Chemicals. We recommend that these data be carefully interpreted, with the goal of establishing baseline exposure information, rather than creating surrogates for conclusions about human health risk.

  11. Assessment of Galactic Cosmic Ray Models and Implications on the Estimation of Radiation Exposure in Space

    NASA Astrophysics Data System (ADS)

    Mrigakshi, A. I.; Matthiä, D.; Berger, T.; Reitz, G.; Wimmer-Schweingruber, R. F.

    2012-12-01

    Astronauts are subjected to elevated levels of high-energy ionizing radiation in space which poses a substantial risk to their health. Therefore, the assessment of the radiation exposure for long duration manned spaceflight is essential. This is done by measuring dose using various detector techniques and by performing numerical simulations utilizing radiation transport codes which allow to predict radiation exposure for future missions and for conditions where measurements are not feasible or available. A necessary prerequisite for an accurate estimation of the exposure using the latter approach is a reliable description of the radiation spectra. Accordingly, in order to estimate the exposure from the Galactic Cosmic Rays (GCRs), which are one of the major sources of radiation exposure in space, GCR models are required. This work presents an evaluation of GCR models for dosimetry purposes and the effect of applying these models on the estimation of GCR exposure in space outside and inside the Earth's magnetosphere. To achieve this, widely used GCR models - Badhwar-O'Neill2010, Burger-Usoskin, CREME2009 and CREME96, were evaluated by comparing model spectra for light and heavy nuclei with measurements from various high-altitude balloon and space missions over several decades. Additionally a new model, based on the GCR-ISO model, developed at the German Aerospace Centre (DLR) was also investigated. The differences arising in the radiation exposure by applying these models are quantified in terms of absorbed dose and dose equivalent rates that were estimated numerically using the GEANT4 Monte-Carlo framework. During certain epochs in the last decade, there are large discrepancies between the model and the measured spectra. All models exhibit weaknesses in describing the increased GCR flux that was observed in 2009-2010. The differences in the spectra, described by the models, result in considerable differences in the estimated dose quantities.

  12. Assessing pesticide exposure of the aquatic environment in tropical catchments

    NASA Astrophysics Data System (ADS)

    Weiss, Frederik; Zurbrügg, Christian; Eggen, Rik; Castillo, Luisa; Ruepert, Clemens; Stamm, Christian

    2015-04-01

    Today, pesticides are intensively used in agriculture across the globe. Worldwide about 2.4×106 tons of pesticides are used annually on 1.6×109 ha of arable land. This yields a global average use of pesticides of 1.53 kg ha-1 year-1. Available data suggest that the use in the agricultural sector will continue to grow. Recently it was estimated that within the last decade, the world pesticide market increased by 93% and the Brazilian market alone by 190%. Though pesticides are intensively used in many low and middle income countries (LAMICs), scientifically sound data of amounts and types of pesticide use and the resulting impact on water quality are lacking in many of these countries. Therefore it is highly relevant to: i) identify risk areas where pesticides affect environmental health, ii) understand the environmental behavior of pesticides in vulnerable tropical ecosystems; and iii) develop possible mitigation options to reduce their exposure to ecosystems and humans. Here we present a project that will focus on assessing pesticide exposure of the aquatic environment and humans in tropical catchments of LAMICs. A catchment in the Zarcero province in Costa Rica will be the test case. Pesticide exposure will be assessed by passive sampling. In order to cover a broad range of compounds of possible use, two sampling devices will be used: SDB membranes for collecting polar compounds and silicon sheets for accumulating apolar pesticides. Extracts will be subsequently analysed by GC-MSMS and LC-HRMS.

  13. Estimating exposure and dose to characterize health risks: the role of human tissue monitoring in exposure assessment.

    PubMed Central

    Sexton, K; Callahan, M A; Bryan, E F

    1995-01-01

    Exposure assessment is an integral part of health risk characterization. Exposure assessments typically address three critical aspects of exposure: the number of people exposed to the environmental toxicant, at specific concentrations, for the time period of interest; the resulting dose; and the relative contribution of important sources and pathways to exposure/dose. Because historically both "point-of-contact" measurements and information about dose and related pharmacokinetic processes have been lacking, exposure assessments have had to rely on construction of "scenarios" to estimate exposure and dose. This could change, however, as advances in development of biologic markers of exposure and dose make it possible to measure and interpret toxicant concentrations in accessible human tissues. The increasing availability of "biomarkers," coupled with improvements in pharmacokinetic understanding, present opportunities to estimate ("reconstruct") exposure from measurements of dose and knowledge of intake and uptake parameters. Human tissue monitoring, however, is not a substitute for more traditional methods of measuring exposure, but rather a complementary approach. A combination of exposure measurements and dose measurements provides the most credible scientific basis for exposure assessment. PMID:7635107

  14. Comparison of residents' pesticide exposure with predictions obtained using the UK regulatory exposure assessment approach.

    PubMed

    Galea, Karen S; MacCalman, Laura; Jones, Kate; Cocker, John; Teedon, Paul; Cherrie, John W; van Tongeren, Martie

    2015-11-01

    The UK regulatory methods currently used for estimating residents' potential pesticide exposure were assessed to determine whether they provide sufficiently conservative estimates. A non-random sample of 149 residents living within 100 m of fields where pesticides were sprayed provided first morning void urine samples one and/or two days after spraying. Using farmers' spray information, regulatory exposure assessment (REA) models were applied to estimate potential pesticide intake among residents, with a toxicokinetic (TK) model used to estimate urinary biomarker concentrations in the mornings of the two days following the spray. These were compared with actual measured urinary biomarker concentrations obtained following the spray applications. The study focused on five pesticides (cypermethrin, penconazole, captan, chlorpyrifos and chlormequat). All measured cypermethrin urinary biomarker levels were lower than the REA-predicted concentrations. Over 98% and 97% of the measured urinary biomarker concentrations for penconazole and captan respectively were lower than the REA-predicted exposures. Although a number of the chlorpyrifos and chlormequat spray-related urinary biomarker concentrations were greater than the predictions, investigation of the background urinary biomarker concentrations suggests these were not significantly different from the levels expected had no pesticide spraying occurred. The majority of measured concentrations being well below the REA-predicted concentrations indicate that, in these cases, the REA is sufficiently conservative.

  15. Comparison of residents' pesticide exposure with predictions obtained using the UK regulatory exposure assessment approach.

    PubMed

    Galea, Karen S; MacCalman, Laura; Jones, Kate; Cocker, John; Teedon, Paul; Cherrie, John W; van Tongeren, Martie

    2015-11-01

    The UK regulatory methods currently used for estimating residents' potential pesticide exposure were assessed to determine whether they provide sufficiently conservative estimates. A non-random sample of 149 residents living within 100 m of fields where pesticides were sprayed provided first morning void urine samples one and/or two days after spraying. Using farmers' spray information, regulatory exposure assessment (REA) models were applied to estimate potential pesticide intake among residents, with a toxicokinetic (TK) model used to estimate urinary biomarker concentrations in the mornings of the two days following the spray. These were compared with actual measured urinary biomarker concentrations obtained following the spray applications. The study focused on five pesticides (cypermethrin, penconazole, captan, chlorpyrifos and chlormequat). All measured cypermethrin urinary biomarker levels were lower than the REA-predicted concentrations. Over 98% and 97% of the measured urinary biomarker concentrations for penconazole and captan respectively were lower than the REA-predicted exposures. Although a number of the chlorpyrifos and chlormequat spray-related urinary biomarker concentrations were greater than the predictions, investigation of the background urinary biomarker concentrations suggests these were not significantly different from the levels expected had no pesticide spraying occurred. The majority of measured concentrations being well below the REA-predicted concentrations indicate that, in these cases, the REA is sufficiently conservative. PMID:26364754

  16. AN OVERVIEW OF THE NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY (NHEXAS) PHASE I STUDIES

    EPA Science Inventory

    The National Human Exposure Assessment Survey (NHEXAS) Phase I studies were sponsored by EPA's Office of Research and Development (ORD) to address critical information needs for assessing human exposures to multiple chemicals from multiple pathways and media. These studies were...

  17. Accurate calculation of binding energies for molecular clusters - Assessment of different models

    NASA Astrophysics Data System (ADS)

    Friedrich, Joachim; Fiedler, Benjamin

    2016-06-01

    In this work we test different strategies to compute high-level benchmark energies for medium-sized molecular clusters. We use the incremental scheme to obtain CCSD(T)/CBS energies for our test set and carefully validate the accuracy for binding energies by statistical measures. The local errors of the incremental scheme are <1 kJ/mol. Since they are smaller than the basis set errors, we obtain higher total accuracy due to the applicability of larger basis sets. The final CCSD(T)/CBS benchmark values are ΔE = - 278.01 kJ/mol for (H2O)10, ΔE = - 221.64 kJ/mol for (HF)10, ΔE = - 45.63 kJ/mol for (CH4)10, ΔE = - 19.52 kJ/mol for (H2)20 and ΔE = - 7.38 kJ/mol for (H2)10 . Furthermore we test state-of-the-art wave-function-based and DFT methods. Our benchmark data will be very useful for critical validations of new methods. We find focal-point-methods for estimating CCSD(T)/CBS energies to be highly accurate and efficient. For foQ-i3CCSD(T)-MP2/TZ we get a mean error of 0.34 kJ/mol and a standard deviation of 0.39 kJ/mol.

  18. Assessing temporal flux of plant hormones in stored processing potatoes using high definition accurate mass spectrometry

    PubMed Central

    Ordaz-Ortiz, José Juan; Foukaraki, Sofia; Terry, Leon Alexander

    2015-01-01

    Plant hormones are important molecules which at low concentration can regulate various physiological processes. Mass spectrometry has become a powerful technique for the quantification of multiple classes of plant hormones because of its high sensitivity and selectivity. We developed a new ultrahigh pressure liquid chromatography–full-scan high-definition accurate mass spectrometry method, for simultaneous determination of abscisic acid and four metabolites phaseic acid, dihydrophaseic acid, 7′-hydroxy-abscisic acid and abscisic acid glucose ester, cytokinins zeatin, zeatin riboside, gibberellins (GA1, GA3, GA4 and GA7) and indole-3-acetyl-L-aspartic acid. We measured the amount of plant hormones in the flesh and skin of two processing potato cvs. Sylvana and Russet Burbank stored for up to 30 weeks at 6 °C under ambient air conditions. Herein, we report for the first time that abscisic acid glucose ester seems to accumulate in the skin of potato tubers throughout storage time. The method achieved a lowest limit of detection of 0.22 ng g−1 of dry weight and a limit of quantification of 0.74 ng g−1 dry weight (zeatin riboside), and was able to recover, detect and quantify a total of 12 plant hormones spiked on flesh and skin of potato tubers. In addition, the mass accuracy for all compounds (<5 ppm) was evaluated. PMID:26504563

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

    SciTech Connect

    Atwell, W.; Weyland, M.D.; Hardy, A.C. NASA, Johnson Space Center, Houston, TX )

    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.

  20. Glove accumulation of pesticide residues for strawberry harvester exposure assessment.

    PubMed

    Li, Yanhong; Chen, Li; Chen, Zhenshan; Coehlo, Joe; Cui, Li; Liu, Yu; Lopez, Terry; Sankaran, Gayatri; Vega, Helen; Krieger, Robert

    2011-06-01

    We investigated the accumulation of pesticide residues on rubber latex gloves that are used by strawberry harvesters to protect their skin, reduce pesticide exposure and promote food safety. Gloves accumulated residues of 16 active ingredients including azoxystrobin, bifenthrin, boscalid, captan, cyprodinil, fenhexamid, fenpropathrin, fludioxonil, hexythiazox, malathion, methomyl, naled, propiconazole, pyraclostrobin, quinoline, and quinoxyfen at different times. Glove residue accumulation (t(½) 2.8-3.7 d) was very similar to the dissipation of DFRs (t(½) 2.1-3.0 d) during the first 3 weeks after malathion applications. Dermal malathion dose was 0.2 mg/kg at the preharvest interval and declined to trace levels during the following 3 months. Glove accumulation of malathion indicated trace surface residue availability and was used to assess the relationship between dislodgable foliar residues and potential hand exposure. PMID:21503692

  1. Application of POCIS for exposure assessment of munitions constituents during constant and fluctuating exposure.

    PubMed

    Belden, Jason B; Lotufo, Guilherme R; Biedenbach, James M; Sieve, Kristal K; Rosen, Gunther

    2015-05-01

    The present study examined the potential use of polar organic chemical integrative samplers (POCIS) for exposure assessment of munitions constituents, including 2,4,6-trinitrotoluene (TNT) and hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), and their breakdown products (aminodinitrotoluenes [ADNTs], diaminonitrotoluenes [DANTs], and hexahydro-1,3,5-trinitroso-1,3,5-triazine [TNX]). Loss of munitions constituents from the sorbent phase after uptake was observed for the "pesticide" POCIS configuration but not for the "pharmaceutical" configuration. Therefore, the latter was selected for further investigation. Under constant exposure conditions, TNT, ADNTs, DANT, RDX, and atrazine (a common environmental contaminant) accumulated at a linear rate for at least 14 d, with sampling rates between 34 mL/d and 215 mL/d. When POCIS were exposed to fluctuating concentrations, analyte accumulation values were similar to values found during constant exposure, indicating that the sampler was indeed integrative. In contrast, caffeine (a common polar contaminant) and TNX did not accumulate at a linear rate and had a reduction in accumulation of greater than 50% on the POCIS during fluctuating exposures, demonstrating that POCIS did not sample those chemicals in an integrative manner. Moreover, in a flow-through microcosm containing the explosive formulation Composition B, TNT and RDX were readily measured using POCIS, despite relatively high turnover rates and thus reduced water concentrations. Mean water concentrations estimated from POCIS were ± 37% of mean water concentrations measured by traditional grab sample collection. Thus, POCIS were found to have high utility for quantifying exposure to most munitions constituents evaluated (TNT, ADNTs, and RDX) and atrazine. PMID:25475692

  2. Assessment of cancer risks due to environmental exposure to asbestos.

    PubMed

    Driece, Hermen A L; Siesling, Sabine; Swuste, Paul H J J; Burdorf, Alex

    2010-07-01

    In a rural area widespread pollution of friable and non-friable waste products was present, used to harden dirt tracks, yards, and driveways during 1935-1974. Exposure to environmental asbestos was assessed by a site approach, based on number of polluted sites within postal code areas, and by a household approach, based on number of households in the close vicinity to polluted sites within postal code areas. Based on asbestos soil investigations, 293 sites were identified with asbestos waste material at the surface, of which 77% contained crocidolite fibres as well as chrysotile fibres. The 293 sites-at-risk varied from 5 m(2) to 2722 m(2) and were surrounded by 347 households within 100 m of these sites. Distance to the plant was associated with the number of sites (r=0.36), and with the number of households (r=0.52). However, categorization of postal code areas into low, intermediate or high likelihood of exposure to asbestos showed a modest agreement between the site and household approach. In the site approach a total of 2.3 million person-years at risk were estimated with an average exposure of 1674 fibres/m(3) and an expected 1.8 cases of malignant mesothelioma each year. The household approach resulted in estimates of 1.2 million person-years at risk, and 0.9 cases of malignant mesothelioma per year, respectively. This study illustrates that asbestos waste on the surface of roads and yards in an area with over 130,000 inhabitants may result in long-term exposure to asbestos that will cause several cases of malignant mesothelioma each year. Although distance to plant, number of polluted sites and number of exposed household were associated, the modest agreement among these measures of exposure indicate that the exposure assessment strategy chosen in a particular study may result in considerable misclassification. Without detailed information on individual behaviour within the polluted area, it is difficult to show that a more individually oriented approach

  3. Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling

    SciTech Connect

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

    2013-10-15

    In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information—inside hotspots or in search of them—based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km{sup 2}. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2 dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96. -- Highlights: • We present an

  4. Genomic Models of Short-Term Exposure Accurately Predict Long-Term Chemical Carcinogenicity and Identify Putative Mechanisms of Action

    PubMed Central

    Gusenleitner, Daniel; Auerbach, Scott S.; Melia, Tisha; Gómez, Harold F.; Sherr, David H.; Monti, Stefano

    2014-01-01

    Background Despite an overall decrease in incidence of and mortality from cancer, about 40% of Americans will be diagnosed with the disease in their lifetime, and around 20% will die of it. Current approaches to test carcinogenic chemicals adopt the 2-year rodent bioassay, which is costly and time-consuming. As a result, fewer than 2% of the chemicals on the market have actually been tested. However, evidence accumulated to date suggests that gene expression profiles from model organisms exposed to chemical compounds reflect underlying mechanisms of action, and that these toxicogenomic models could be used in the prediction of chemical carcinogenicity. Results In this study, we used a rat-based microarray dataset from the NTP DrugMatrix Database to test the ability of toxicogenomics to model carcinogenicity. We analyzed 1,221 gene-expression profiles obtained from rats treated with 127 well-characterized compounds, including genotoxic and non-genotoxic carcinogens. We built a classifier that predicts a chemical's carcinogenic potential with an AUC of 0.78, and validated it on an independent dataset from the Japanese Toxicogenomics Project consisting of 2,065 profiles from 72 compounds. Finally, we identified differentially expressed genes associated with chemical carcinogenesis, and developed novel data-driven approaches for the molecular characterization of the response to chemical stressors. Conclusion Here, we validate a toxicogenomic approach to predict carcinogenicity and provide strong evidence that, with a larger set of compounds, we should be able to improve the sensitivity and specificity of the predictions. We found that the prediction of carcinogenicity is tissue-dependent and that the results also confirm and expand upon previous studies implicating DNA damage, the peroxisome proliferator-activated receptor, the aryl hydrocarbon receptor, and regenerative pathology in the response to carcinogen exposure. PMID:25058030

  5. Assessment of exposure to mixture pollutants in Mexican indigenous children.

    PubMed

    Flores-Ramírez, R; Pérez-Vázquez, F J; Cilia-López, V G; Zuki-Orozco, B A; Carrizales, L; Batres-Esquivel, L E; Palacios-Ramírez, A; Díaz-Barriga, F

    2016-05-01

    The aim of the present work was to complete an exposure assessment in three Mexican indigenous communities using the community-based health risk assessment, which is the first step in the CHILD framework. We used 1-hydroxypyrene (1-OHP) as an exposure biomarker to polycyclic aromatic hydrocarbons (PAHs) and trans, trans-muconic acid (t,t-MA) as an exposure biomarker to benzene, persistent organic pollutants (POPs), lead, manganese, arsenic, and fluoride. Anthropometric measurements were also taken. In these communities, high percentages of children with chronic malnutrition were found (28 to 49 %) based on their weight and age. All communities showed a high percentage of children with detectable levels of four or more compounds (70 to 82 %). Additionally, our results showed that in indigenous communities, children are exposed to elevated levels of certain environmental pollutants, including manganese with 17.6, 16.8, and 7.3 μg/L from SMP, TOC, and CUA, respectively. Lead and HCB levels were similar in the indigenous communities (2.5, 3.1, and 4.2 μg/dL and 2.5, 3.1, and 3.7 ng/mL, respectively). 1-OHP and t,t-MA levels were higher in TOC (0.8 μmol/mol of creatinine, 476 μg/g of creatinine, respectively) when compared with SMP (0.1 μmol/mol of creatinine, 215.5 μg/g of creatinine, respectively) and CUA (0.1 μmol/mol of creatinine, 185.2 μg/g of creatinine, respectively). DDE levels were 30.7, 26.9, and 9.6 ng/mL in CUA, SMP, and TOC, respectively. The strength of this study is that it assesses exposure to pollutants with indications for the resultant risk before an intervention is made by the CHILD program to manage this risk in the indigenous communities. Considering the large number of people, especially children, exposed to multiple pollutants, it is important to design effective intervention programs that reduce exposure and the resultant risk in the numerous indigenous communities in Mexico.

  6. Chromatography paper as a low-cost medium for accurate spectrophotometric assessment of blood hemoglobin concentration.

    PubMed

    Bond, Meaghan; Elguea, Carlos; Yan, Jasper S; Pawlowski, Michal; Williams, Jessica; Wahed, Amer; Oden, Maria; Tkaczyk, Tomasz S; Richards-Kortum, Rebecca

    2013-06-21

    Anemia affects a quarter of the world's population, and a lack of appropriate diagnostic tools often prevents treatment in low-resource settings. Though the HemoCue 201+ is an appropriate device for diagnosing anemia in low-resource settings, the high cost of disposables ($0.99 per test in Malawi) limits its availability. We investigated using spectrophotometric measurement of blood spotted on chromatography paper as a low-cost (<$0.01 per test) alternative to HemoCue cuvettes. For this evaluation, donor blood was diluted with plasma to simulate anemia, a micropipette spotted blood on paper, and a bench-top spectrophotometer validated the approach before the development of a low-cost reader. We optimized impregnating paper with chemicals to lyse red blood cells, paper type, drying time, wavelengths measured, and sensitivity to variations in volume of blood, and we validated our approach using patient samples. Lysing the blood cells with sodium deoxycholate dried in Whatman Chr4 chromatography paper gave repeatable results, and the absorbance difference between 528 nm and 656 nm was stable over time in measurements taken up to 10 min after sample preparation. The method was insensitive to the amount of blood spotted on the paper over the range of 5 μL to 25 μL. We created a low-cost, handheld reader to measure the transmission of paper cuvettes at these optimal wavelengths. Training and validating our method with patient samples on both the spectrometer and the handheld reader showed that both devices are accurate to within 2 g dL(-1) of the HemoCue device for 98% and 95% of samples, respectively.

  7. A Cost-Benefit and Accurate Method for Assessing Microalbuminuria: Single versus Frequent Urine Analysis

    PubMed Central

    Hemmati, Roholla; Gharipour, Mojgan; Khosravi, Alireza; Jozan, Mahnaz

    2013-01-01

    Background. The purpose of this study was to answer the question whether a single testing for microalbuminuria results in a reliable conclusion leading costs saving. Methods. This current cross-sectional study included a total of 126 consecutive persons. Microalbuminuria was assessed by collection of two fasting random urine specimens on arrival to the clinic as well as one week later in the morning. Results. In overall, 17 out of 126 participants suffered from microalbuminuria that, among them, 12 subjects were also diagnosed as microalbuminuria once assessing this factor with a sensitivity of 70.6%, a specificity of 100%, a PPV of 100%, a NPV of 95.6%, and an accuracy of 96.0%. The measured sensitivity, specificity, PVV, NPV, and accuracy in hypertensive patients were 73.3%, 100%, 100%, 94.8%, and 95.5%, respectively. Also, these rates in nonhypertensive groups were 50.0%, 100%, 100%, 97.3%, and 97.4%, respectively. According to the ROC curve analysis, a single measurement of UACR had a high value for discriminating defected from normal renal function state (c = 0.989). Urinary albumin concentration in a single measurement had also high discriminative value for diagnosis of damaged kidney (c = 0.995). Conclusion. The single testing of both UACR and urine albumin level rather frequent testing leads to high diagnostic sensitivity, specificity, and accuracy as well as high predictive values in total population and also in hypertensive subgroups. PMID:24455207

  8. Assessment of exposure to the Penicillium glabrum complex in cork industry using complementing methods.

    PubMed

    Viegas, Carla; Sabino, Raquel; Botelho, Daniel; dos Santos, Mateus; Gomes, Anita Quintal

    2015-09-01

    Cork oak is the second most dominant forest species in Portugal and makes this country the world leader in cork export. Occupational exposure to Chrysonilia sitophila and the Penicillium glabrum complex in cork industry is common, and the latter fungus is associated with suberosis. However, as conventional methods seem to underestimate its presence in occupational environments, the aim of our study was to see whether information obtained by polymerase chain reaction (PCR), a molecular-based method, can complement conventional findings and give a better insight into occupational exposure of cork industry workers. We assessed fungal contamination with the P. glabrum complex in three cork manufacturing plants in the outskirts of Lisbon using both conventional and molecular methods. Conventional culturing failed to detect the fungus at six sampling sites in which PCR did detect it. This confirms our assumption that the use of complementing methods can provide information for a more accurate assessment of occupational exposure to the P. glabrum complex in cork industry.

  9. Can script concordance testing be used in nursing education to accurately assess clinical reasoning skills?

    PubMed

    Dawson, Tyia; Comer, Linda; Kossick, Mark A; Neubrander, Judy

    2014-05-01

    The Script Concordance Test (SCT) has been used successfully in medical schools to assess clinical reasoning in medical students, but it has not been widely used in nursing education. The purpose of this study was to provide additional evidence of the validity and reliability of the SCT in evaluating clinical reasoning in nursing students by replicating a previous study. The test was administered to 48 first-year Bachelor of Science in Nursing students. A scoring grid was developed using the aggregate scores method based on the modal responses of 13 panel members. The reliability of the scores was measured by Cronbach's alpha coefficient, and the scores of the students and the panel were compared using a t test. The difference between the panel's and the students' scores was statistically significant, and the reliability of the scores is high. The SCT provides a reliable, standardized, and easy-to-administer method of evaluating clinical reasoning in nursing students.

  10. Accurate assessment of the biodegradation of cationic surfactants in activated sludge reactors (OECD TG 303A).

    PubMed

    Geerts, Roy; van Ginkel, Cornelis G; Plugge, Caroline M

    2015-08-01

    The continuous-fed activated sludge test (OECD TG 303A) was used to predict the removal of cationic surfactants from wastewater in activated sludge plants. However, a method to differentiate between adsorption and biodegradation is not provided in these guidelines. Assessment of removal by biodegradation was possible with analysis of the surfactant present in mixed liquid suspended solids in combination with a simple equation. This equation was derived from the mass balance of the activated sludge unit in steady state. The removal by biodegradation of decylamine, tetradecylamine, octadecylamine, dioctadecylmethylamine and dioctadecyldimethylammonium chloride that have different capacities to adsorb was >99.9%, >99.9%, 98.2%, 94.2%, and 69.0%, respectively. The total removal of all five cationic surfactants from the influent was ≥98.8%. The removal of octadecylamine spiked at different influent concentrations indicated first order kinetics. PMID:25913361

  11. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals’ Behaviour

    PubMed Central

    Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs’ behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals’ quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog’s shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  12. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.

    PubMed

    Barnard, Shanis; Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  13. Quick, Accurate, Smart: 3D Computer Vision Technology Helps Assessing Confined Animals' Behaviour.

    PubMed

    Barnard, Shanis; Calderara, Simone; Pistocchi, Simone; Cucchiara, Rita; Podaliri-Vulpiani, Michele; Messori, Stefano; Ferri, Nicola

    2016-01-01

    Mankind directly controls the environment and lifestyles of several domestic species for purposes ranging from production and research to conservation and companionship. These environments and lifestyles may not offer these animals the best quality of life. Behaviour is a direct reflection of how the animal is coping with its environment. Behavioural indicators are thus among the preferred parameters to assess welfare. However, behavioural recording (usually from video) can be very time consuming and the accuracy and reliability of the output rely on the experience and background of the observers. The outburst of new video technology and computer image processing gives the basis for promising solutions. In this pilot study, we present a new prototype software able to automatically infer the behaviour of dogs housed in kennels from 3D visual data and through structured machine learning frameworks. Depth information acquired through 3D features, body part detection and training are the key elements that allow the machine to recognise postures, trajectories inside the kennel and patterns of movement that can be later labelled at convenience. The main innovation of the software is its ability to automatically cluster frequently observed temporal patterns of movement without any pre-set ethogram. Conversely, when common patterns are defined through training, a deviation from normal behaviour in time or between individuals could be assessed. The software accuracy in correctly detecting the dogs' behaviour was checked through a validation process. An automatic behaviour recognition system, independent from human subjectivity, could add scientific knowledge on animals' quality of life in confinement as well as saving time and resources. This 3D framework was designed to be invariant to the dog's shape and size and could be extended to farm, laboratory and zoo quadrupeds in artificial housing. The computer vision technique applied to this software is innovative in non

  14. Exposure assessment of workers in printed electronics workplace.

    PubMed

    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.

  15. Mercury contamination and exposure assessment of fishery products in Korea.

    PubMed

    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.

  16. Mercury contamination and exposure assessment of fishery products in Korea.

    PubMed

    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. PMID:25249274

  17. Dietary exposure to copper in the European Union and its assessment for EU regulatory risk assessment.

    PubMed

    Sadhra, Steven S; Wheatley, Andrew D; Cross, Hilary J

    2007-03-15

    EU legislation requires a multimedia exposure assessment for substances supplied within the EU. Dietary intake is the main source of exposure for the majority of the population hence an essential component of the human risk assessment. This paper describes the available data for dietary copper and its use in estimating daily intake including variability and determinants of exposure. Typical and reasonable worst-case estimates are derived for the general population from the available peer reviewed literature. Intakes from drinking water are found to exhibit more variability than those from food. Therefore, different exposure scenarios are derived to reflect the range of acute and chronic exposures that may occur. Estimates of typical copper intakes for the EU population are in the range 0.8-1.8 mg/day. Typical copper intakes of men are higher than those of women while the intake among the general adult population is higher than that of the elderly. Intakes of both men and women are generally close to the WHO normative requirements but may be somewhat lower in specific locations where background levels of copper are unusually low. Alcoholic beverages represent minor contribution daily copper intakes. Intakes for children are rather variable ranging broadly from 0.7 to 1.5 mg/day and are somewhat age and sex dependent. Greater uncertainty applies to the assessment of local exposure incorporating food produced on land directly impacted by contemporary copper industry emissions. Specifically, the extent to which soil is enriched in copper in these conditions is unclear. However, effective homeostatic control mechanisms in plants limit uptake and transfer to the human food chain. A best estimate of 0.25 mg/day in addition to regional exposure was derived. Drinking water is estimated to contribute only marginally to total copper intake in most cases. Higher intakes may occur in areas of poor water quality and/or corroded distribution systems. Such elevated exposures

  18. Dietary exposure to copper in the European Union and its assessment for EU regulatory risk assessment.

    PubMed

    Sadhra, Steven S; Wheatley, Andrew D; Cross, Hilary J

    2007-03-15

    EU legislation requires a multimedia exposure assessment for substances supplied within the EU. Dietary intake is the main source of exposure for the majority of the population hence an essential component of the human risk assessment. This paper describes the available data for dietary copper and its use in estimating daily intake including variability and determinants of exposure. Typical and reasonable worst-case estimates are derived for the general population from the available peer reviewed literature. Intakes from drinking water are found to exhibit more variability than those from food. Therefore, different exposure scenarios are derived to reflect the range of acute and chronic exposures that may occur. Estimates of typical copper intakes for the EU population are in the range 0.8-1.8 mg/day. Typical copper intakes of men are higher than those of women while the intake among the general adult population is higher than that of the elderly. Intakes of both men and women are generally close to the WHO normative requirements but may be somewhat lower in specific locations where background levels of copper are unusually low. Alcoholic beverages represent minor contribution daily copper intakes. Intakes for children are rather variable ranging broadly from 0.7 to 1.5 mg/day and are somewhat age and sex dependent. Greater uncertainty applies to the assessment of local exposure incorporating food produced on land directly impacted by contemporary copper industry emissions. Specifically, the extent to which soil is enriched in copper in these conditions is unclear. However, effective homeostatic control mechanisms in plants limit uptake and transfer to the human food chain. A best estimate of 0.25 mg/day in addition to regional exposure was derived. Drinking water is estimated to contribute only marginally to total copper intake in most cases. Higher intakes may occur in areas of poor water quality and/or corroded distribution systems. Such elevated exposures

  19. Assessing the effects of sodium hypochlorite exposure on the characteristics of PVDF based membranes.

    PubMed

    Abdullah, Syed Z; Bérubé, Pierre R

    2013-09-15

    Sodium hypochlorite is commonly used as a cleaning agent to remove adsorbed foulants from PVDF based micro/ultra filtration membranes in water and wastewater treatment applications. Although effective for fouling control, extended sodium hypochlorite exposure can affect the physical/chemical characteristics and hinder the treatment performance of these membranes. To assess these effects, PVDF based membranes were exposed to sodium hypochlorite at different concentrations for varying periods of time, and the physical/chemical characteristics of the virgin and sodium hypochlorite exposed membranes were compared. The membranes were characterized based on chemical composition (FTIR and NMR), mechanical strength (yield strength), surface hydrophilicity (contact angle), pore size and porosity (scanning electron microscopy and challenge test), and membrane resistance (clean water permeation test). The results indicated that exposure dose and concentration of the sodium hypochlorite used have significant influence on the membrane characteristics. The impact of sodium hypochlorite exposure on the parameters investigated could be most accurately and consistently correlated to an exposure dose relationship of the form C(n)t (where, C = concentration and t = exposure time) rather than the Ct relationship commonly used to define the extent of exposure to cleaning agents. For all the parameters investigated, the power coefficient n was less than 1 indicating that time had a greater impact on the changes than did the concentration of the sodium hypochlorite. The results suggest that the use of sodium hypochlorite for chemical cleaning, at concentrations that are higher than those typically used for chemical cleaning would have less of an effect on the characteristics of the membrane materials. Changes in the characteristics were attributed to the oxidation of the hydrophilic additives (HA) present in blended PVDF membranes.

  20. Agricultural burning smoke in Eastern Washington: Part II. Exposure assessment

    NASA Astrophysics Data System (ADS)

    Wu, Chang-Fu; Jimenez, Jorge; Claiborn, Candis; Gould, Tim; Simpson, Christopher D.; Larson, Tim; Sally Liu, L.-J.

    Several studies have documented potential health effects due to agricultural burning smoke. However, there is a paucity of literature characterizing community residents' exposure to agricultural burning smoke. This study assesses personal exposures to particulate matter (PM) with aerodynamic diameters <2.5 μm (PM 2.5) from agriculture burning smoke ( Eb) for 33 asthmatic adults in Pullman, WA. PM 2.5 concentrations were measured on 16 subjects, inside of all but four residences, outside of 6 residences, and at a central site. The mean±standard deviation of personal exposure to PM 2.5 was 13.8±11.1 μg m -3, which was on average 8.0 μg m -3 higher during the agricultural burning episodes (19.0±11.8 μg m -3) than non-episodes (11.0±9.7 μg m -3). The levoglucosan (LG, a unique marker for biomass burning PM) on personal filter samples also was higher during the episodes than non-episodes (0.026±0.030 vs. 0.010±0.012 μg m -3). We applied the random component superposition model on central-site and home indoor PM measurements, and estimated a central-site infiltration factor between 0.21 and 2.05 for residences with good modeling performance. We combined the source apportionment and total exposure modeling results to estimate individual Eb, which ranged from 1.2 to 6.7 μg m -3 and correlated with personal LG with an r of 0.51. The sensitivity analysis of applying the infiltration efficiency estimated from the recursive model showed that the Eb (range: 1.3-4.3 μg m -3) obtained from this approach have a higher correlation with personal LG ( r=0.75). Nevertheless, the small sample size of personal LG measurements prevents a comparative and conclusive assessment of the model performance. We found a significant between-subject variation between episodes and non-episodes in both the Eb estimates and subjects' activity patterns. This suggests that the LG measurements at the central site may not always represent individual exposures to agricultural burning smoke

  1. Assessing the Health and Performance Risks of Carbon Dioxide Exposures

    NASA Technical Reports Server (NTRS)

    James, John T.; Meyers, V. E.; Alexander, D.

    2010-01-01

    provide no more than partial answers to the questions of environmental interactions, interindividual variability, and optimal control levels. Future prospective studies should involve assessment of astronaut well being using sophisticated measures during exposures to levels of CO2 in the range from 2 to 8 mmHg.

  2. Accurate assessment of the impact of salmon farming on benthic sediment enrichment using foraminiferal metabarcoding.

    PubMed

    Pochon, X; Wood, S A; Keeley, N B; Lejzerowicz, F; Esling, P; Drew, J; Pawlowski, J

    2015-11-15

    Assessing the environmental impact of salmon farms on benthic systems is traditionally undertaken using biotic indices derived from microscopic analyses of macrobenthic infaunal (MI) communities. In this study, we tested the applicability of using foraminiferal-specific high-throughput sequencing (HTS) metabarcoding for monitoring these habitats. Sediment samples and physico-chemical data were collected along an enrichment gradient radiating out from three Chinook salmon (Oncorhynchus tshawytscha) farms in New Zealand. HTS of environmental DNA and RNA (eDNA/eRNA) resulted in 1,875,300 sequences that clustered into 349 Operational Taxonomic Units. Strong correlations were observed among various biotic indices calculated from MI data and normalized fourth-root transformed HTS data. Correlations were stronger using eRNA compared to eDNA data. Quantile regression spline analyses identified 12 key foraminiferal taxa that have potential to be used as bioindicator species. This study demonstrates the huge potential for using this method for biomonitoring of fish-farming and other marine industrial activities. PMID:26337228

  3. Health risk assessment for inhalation exposure to arsenic.

    PubMed

    Fabiánová, E; Hettychová, L; Koppová, K; Hrubá, F; Marko, M; Maroni, M; Grech, G; Bencko, V

    2000-02-01

    Health risk assessment was used as the formal process to estimate the likelihood and magnitude of the health effects occurring in humans as a result of environmental and occupational exposure to polluting agents. This study was focused at estimating the human health risk of the general and working population living in the region polluted by arsenic for more than 40 years, from combustion of coal with high arsenic content in the power plant. The exposure to arsenic from inhalation was under investigation. A study period of 40 years (1973-1993) was chosen. The study period was defined taking into account, besides the availability of data, the temporal patterns of the technological processes and the trends over time of environmental concentrations. The results from the arsenic risk assessment study were used for the evaluation of the health risk for different population groups in the polluted areas and for different professions of workers exposed to As in a power plant. The results are applicable for the evaluation of risk in real conditions, for health surveillance and for remedial changes and a potential suggestion on technological improvement.

  4. Assessing potential exposure of birds to pesticide-treated seeds.

    PubMed

    Prosser, Phil; Hart, A D M

    2005-10-01

    Seed treatments are widely used for crop protection and present a particular risk to granivorous birds. UK risk assessment for seed treatments has tended to focus on highly granivorous species; however, under some conditions, non-granivorous birds will take seeds. Better data is needed on which species eat seeds for which pesticide treatments are used. To identify which species will take and eat a range of crop seeds in common usage in the UK, birds visiting bait stations at which untreated seed was presented were video recorded. Information was also obtained on how much seed is taken by individual birds. The seeds tested were wheat, barley, maize, oilseed rape, grass, peas and pelleted sugar beet. For many of the species observed at the bait stations, the amounts of seed consumed during single visits were sufficient to pose a potential risk (toxicity-exposure ratio < 10) if the seed had been treated with one of the more acutely toxic seed treatments. Previous studies have shown that de-husking of seeds can substantially reduce birds' exposure. This paper provides information on which of the species recorded de-husked which seeds, in field conditions. The use of these data in pesticide risk assessment is considered.

  5. Future research needs associated with the assessment of potential human health risks from exposure to toxic ambient air pollutants.

    PubMed Central

    Möller, L; Schuetzle, D; Autrup, H

    1994-01-01

    This paper presents key conclusions and future research needs from a Workshop on the Risk Assessment of Urban Air, Emissions, Exposure, Risk Identification, and Quantification, which was held in Stockholm during June 1992 by 41 participants from 13 countries. Research is recommended in the areas of identification and quantification of toxics in source emissions and ambient air, atmospheric transport and chemistry, exposure level assessment, the development of improved in vitro bioassays, biomarker development, the development of more accurate epidemiological methodologies, and risk quantification techniques. Studies are described that will be necessary to assess and reduce the level of uncertainties associated with each step of the risk assessment process. International collaborative research efforts between industry and government organizations are recommended as the most effective way to carry out this research. PMID:7529703

  6. Use of human in vitro skin models for accurate and ethical risk assessment: metabolic considerations.

    PubMed

    Hewitt, Nicola J; Edwards, Robert J; Fritsche, Ellen; Goebel, Carsten; Aeby, Pierre; Scheel, Julia; Reisinger, Kerstin; Ouédraogo, Gladys; Duche, Daniel; Eilstein, Joan; Latil, Alain; Kenny, Julia; Moore, Claire; Kuehnl, Jochen; Barroso, Joao; Fautz, Rolf; Pfuhler, Stefan

    2013-06-01

    Several human skin models employing primary cells and immortalized cell lines used as monocultures or combined to produce reconstituted 3D skin constructs have been developed. Furthermore, these models have been included in European genotoxicity and sensitization/irritation assay validation projects. In order to help interpret data, Cosmetics Europe (formerly COLIPA) facilitated research projects that measured a variety of defined phase I and II enzyme activities and created a complete proteomic profile of xenobiotic metabolizing enzymes (XMEs) in native human skin and compared them with data obtained from a number of in vitro models of human skin. Here, we have summarized our findings on the current knowledge of the metabolic capacity of native human skin and in vitro models and made an overall assessment of the metabolic capacity from gene expression, proteomic expression, and substrate metabolism data. The known low expression and function of phase I enzymes in native whole skin were reflected in the in vitro models. Some XMEs in whole skin were not detected in in vitro models and vice versa, and some major hepatic XMEs such as cytochrome P450-monooxygenases were absent or measured only at very low levels in the skin. Conversely, despite varying mRNA and protein levels of phase II enzymes, functional activity of glutathione S-transferases, N-acetyltransferase 1, and UDP-glucuronosyltransferases were all readily measurable in whole skin and in vitro skin models at activity levels similar to those measured in the liver. These projects have enabled a better understanding of the contribution of XMEs to toxicity endpoints. PMID:23539547

  7. Establishment of an x-ray standard calibration curve by conventional dicentric analysis as prerequisite for accurate radiation dose assessment.

    PubMed

    Beinke, Christina; Braselmann, Herbert; Meineke, Viktor

    2010-02-01

    The dicentric assay was established to carry out cytogenetic biodosimetry after suspected radiation overexposure, including a comprehensive documentation system to record the processing of the specimen, all data, results, and stored information. As an essential prerequisite for retrospective radiation dose assessment, a dose-response curve for dicentric induction by in vitro x-ray irradiation of peripheral blood samples was produced. The accelerating potential was 240 kV (maximum photon energy: 240 keV). A total of 8,377 first-division metaphases of four healthy volunteers were analyzed after exposure to doses ranging from 0.2 to 4.0 Gy at a dose rate of 1.0 Gy min. The background level of aberrations at 0-dose was determined by the analysis of 14,522 first-division metaphases obtained from unirradiated blood samples of 10 healthy volunteers. The dose-response relationship follows a linear-quadratic equation, Y = c + alphaD + betaD, with the coefficients c = 0.0005 +/- 0.0002, alpha = 0.043 +/- 0.006, and beta = 0.063 +/- 0.004. The technical competence and the quality of the calibration curve were assessed by determination of the dose prediction accuracy in an in vitro experiment simulating whole-body exposures within a range of 0.2 to 2.0 Gy. Dose estimations were derived by scoring up to 500-1,000 metaphase spreads or more (full estimation mode) and by evaluating only 50 metaphase spreads (triage mode) per subject. The triage mode was applied by performing manifold evaluations of the full estimation data in order to test the robustness of the curve for triage purposes and to assess possible variations among the estimated doses referring to a single exposure and preparation.

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

    PubMed

    Leitgeb, N

    2008-01-21

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  10. Developing and evaluating distributions for probabilistic human exposure assessments

    SciTech Connect

    Maddalena, Randy L.; McKone, Thomas E.

    2002-08-01

    This report describes research carried out at the Lawrence Berkeley National Laboratory (LBNL) to assist the U. S. Environmental Protection Agency (EPA) in developing a consistent yet flexible approach for evaluating the inputs to probabilistic risk assessments. The U.S. EPA Office of Emergency and Remedial Response (OERR) recently released Volume 3 Part A of Risk Assessment Guidance for Superfund (RAGS), as an update to the existing two-volume set of RAGS. The update provides policy and technical guidance on performing probabilistic risk assessment (PRA). Consequently, EPA risk managers and decision-makers need to review and evaluate the adequacy of PRAs for supporting regulatory decisions. A critical part of evaluating a PRA is the problem of evaluating or judging the adequacy of input distributions PRA. Although the overarching theme of this report is the need to improve the ease and consistency of the regulatory review process, the specific objectives are presented in two parts. The objective of Part 1 is to develop a consistent yet flexible process for evaluating distributions in a PRA by identifying the critical attributes of an exposure factor distribution and discussing how these attributes relate to the task-specific adequacy of the input. This objective is carried out with emphasis on the perspective of a risk manager or decision-maker. The proposed evaluation procedure provides consistency to the review process without a loss of flexibility. As a result, the approach described in Part 1 provides an opportunity to apply a single review framework for all EPA regions and yet provide the regional risk manager with the flexibility to deal with site- and case-specific issues in the PRA process. However, as the number of inputs to a PRA increases, so does the complexity of the process for calculating, communicating and managing risk. As a result, there is increasing effort required of both the risk professionals performing the analysis and the risk manager

  11. Evidence that bisphenol A (BPA) can be accurately measured without contamination in human serum and urine, and that BPA causes numerous hazards from multiple routes of exposure.

    PubMed

    vom Saal, Frederick S; Welshons, Wade V

    2014-12-01

    There is extensive evidence that bisphenol A (BPA) is related to a wide range of adverse health effects based on both human and experimental animal studies. However, a number of regulatory agencies have ignored all hazard findings. Reports of high levels of unconjugated (bioactive) serum BPA in dozens of human biomonitoring studies have also been rejected based on the prediction that the findings are due to assay contamination and that virtually all ingested BPA is rapidly converted to inactive metabolites. NIH and industry-sponsored round robin studies have demonstrated that serum BPA can be accurately assayed without contamination, while the FDA lab has acknowledged uncontrolled assay contamination. In reviewing the published BPA biomonitoring data, we find that assay contamination is, in fact, well controlled in most labs, and cannot be used as the basis for discounting evidence that significant and virtually continuous exposure to BPA must be occurring from multiple sources.

  12. Evidence that bisphenol A (BPA) can be accurately measured without contamination in human serum and urine, and that BPA causes numerous hazards from multiple routes of exposure

    PubMed Central

    vom Saal, Frederick S.; Welshons, Wade V.

    2016-01-01

    There is extensive evidence that bisphenol A (BPA) is related to a wide range of adverse health effects based on both human and experimental animal studies. However, a number of regulatory agencies have ignored all hazard findings. Reports of high levels of unconjugated (bioactive) serum BPA in dozens of human biomonitoring studies have also been rejected based on the prediction that the findings are due to assay contamination and that virtually all ingested BPA is rapidly converted to inactive metabolites. NIH and industry-sponsored round robin studies have demonstrated that serum BPA can be accurately assayed without contamination, while the FDA lab has acknowledged uncontrolled assay contamination. In reviewing the published BPA biomonitoring data, we find that assay contamination is, in fact, well controlled in most labs, and cannot be used as the basis for discounting evidence that significant and virtually continuous exposure to BPA must be occurring from multiple sources. PMID:25304273

  13. Occupational dermal exposure to nanoparticles and nano-enabled products: Part 2, exploration of exposure processes and methods of assessment.

    PubMed

    Brouwer, Derk H; Spaan, Suzanne; Roff, Martin; Sleeuwenhoek, Anne; Tuinman, Ilse; Goede, Henk; van Duuren-Stuurman, Birgit; Filon, Francesca Larese; Bello, Dhimiter; Cherrie, John W

    2016-08-01

    Over the past decade, the primary focus of nanotoxicology and nanoenvironmental health and safety efforts has been largely on inhalation exposure to engineered nanomaterials, at the production stage, and much less on considering risks along the life cycle of nano-enabled products. Dermal exposure to nanomaterials and its health impact has been studied to a much lesser extent, and mostly in the context of intentional exposure to nano-enabled products such as in nanomedicine, cosmetics and personal care products. How concerning is dermal exposure to such nanoparticles in the context of occupational exposures? When and how should we measure it? In the first of a series of two papers (Larese Filon et al., 2016), we focused our attention on identifying conditions or situations, i.e. a combination of nanoparticle physico-chemical properties, skin barrier integrity, and occupations with high prevalence of skin disease, which deserve further investigation. This second paper focuses on the broad question of dermal exposure assessment to nanoparticles and attempts to give an overview of the mechanisms of occupational dermal exposure to nanoparticles and nano-enabled products and explores feasibility and adequacy of various methods of quantifying dermal exposure to NOAA. We provide here a conceptual framework for screening, prioritization, and assessment of dermal exposure to NOAA in occupational settings, and integrate it into a proposed framework for risk assessment.

  14. Occupational dermal exposure to nanoparticles and nano-enabled products: Part 2, exploration of exposure processes and methods of assessment.

    PubMed

    Brouwer, Derk H; Spaan, Suzanne; Roff, Martin; Sleeuwenhoek, Anne; Tuinman, Ilse; Goede, Henk; van Duuren-Stuurman, Birgit; Filon, Francesca Larese; Bello, Dhimiter; Cherrie, John W

    2016-08-01

    Over the past decade, the primary focus of nanotoxicology and nanoenvironmental health and safety efforts has been largely on inhalation exposure to engineered nanomaterials, at the production stage, and much less on considering risks along the life cycle of nano-enabled products. Dermal exposure to nanomaterials and its health impact has been studied to a much lesser extent, and mostly in the context of intentional exposure to nano-enabled products such as in nanomedicine, cosmetics and personal care products. How concerning is dermal exposure to such nanoparticles in the context of occupational exposures? When and how should we measure it? In the first of a series of two papers (Larese Filon et al., 2016), we focused our attention on identifying conditions or situations, i.e. a combination of nanoparticle physico-chemical properties, skin barrier integrity, and occupations with high prevalence of skin disease, which deserve further investigation. This second paper focuses on the broad question of dermal exposure assessment to nanoparticles and attempts to give an overview of the mechanisms of occupational dermal exposure to nanoparticles and nano-enabled products and explores feasibility and adequacy of various methods of quantifying dermal exposure to NOAA. We provide here a conceptual framework for screening, prioritization, and assessment of dermal exposure to NOAA in occupational settings, and integrate it into a proposed framework for risk assessment. PMID:27283207

  15. HEALTH EFFECTS OF CHRONIC EXPOSURE TO ARSENIC VIA DRINKING WATER IN INNER MONGOLIA: I. BIOMARKERS FOR ASSESSING EXPOSURE AND EFFECTS

    EPA Science Inventory

    Health Effects of Chronic Exposure to Arsenic via Drinking Water in Inner Mongolia: I. Biomarkers for Assessing Exposure and Effects

    Judy L. Mumford, Ph.D., Mike Schmitt, M.S.P.H., Richard K. Kwok, M.S.P.H., Rebecca Calderon, Ph.D., National Health and Environmental Effect...

  16. [Assessment of telephone operators' exposure to sound through headphones].

    PubMed

    Kawanami, Shoko; Inoue, Jinro; Takahashi, Koko; Horie, Seichi

    2011-09-01

    We estimated the level of noise that telephone operators were exposed to through headphones by a two-step method using an artificial ear technique and a manikin technique. In the artificial ear technique, the sound pressure level (Leq) of the total work hours was 81.5 dB, whereas the Leq of the total duration of phone calls was 89.3 dB. Therefore, we conducted a more accurate measurement by the manikin technique (ISO11904-2). By this method, we could simulate the headphone-wearing condition of the workers and convert the measurements to a diffuse-field related L(Aeq). By this manikin technique, the corrected L(Aeq) of the total work hours was 68.3 dB, whereas the corrected L(Aeq) of the total duration of call was 76.6 dB, which was below the standard of the Occupational Exposure Limits of the Japan Society of Occupational Health. We confirmed that in a workplace where the background noise is low (51.3 dBA), a good signal-noise ratio is maintained so that operators don't have to listen to loud sounds through headphones. Neither the gender nor the type of the telephone equipment of the callers affected the sound pressure levels.

  17. New approach for assessing human perfluoroalkyl exposure via hair.

    PubMed

    Alves, Andreia; Jacobs, Griet; Vanermen, Guido; Covaci, Adrian; Voorspoels, Stefan

    2015-11-01

    In the recent years hair has been increasingly used as alternative matrix in human biomonitoring (HBM) of environmental pollutants. Sampling advantages and time integration of exposure assessment seems the most attractive features of hair matrix. In the current study, a novel miniaturized method was developed and validated for measuring 15 perfluoroalkyl substances (PFAS), including perfluoro n-butanoic acid (PFBA), perfluoro n-pentanoic acid (PFPeA), perfluoro n-hexanoic acid (PFHxA), perfluoro n-heptanoic acid (PFHpA), perfluor n-octanoic acid (PFOA), perfluoro n-nonanoic acid (PFNA), perfluoro tetradecanoic acid (PFTeDA), perfluorobutane sulfonic acid (PFBS), perfluoro pentane sulfonic acid (PFPeS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS), perfluorooctane sulfonic acid (PFOS), perfluorononane sulfonic acid (PFNS), perfluorodecane sulfonic acid (PFDS) and perfluorododecane sulfonic acid (PFDoS) in human hair by liquid chromatography tandem mass spectrometry (LC-MS/MS). After extraction using ethyl acetate, dispersive ENVI-Carb was used for clean-up. Good intra- and inter-day precision for low (LQ 5 ng/g hair) and high spike (HQ 15n g/g) levels were achieved (in general RSD <10%). The accuracy was assessed using recoveries (%), which ranged between 68-118% (LQ) and 70-121% (HQ). The instrumental limit of detection (LODi) and limit of quantification (LOQi) were between 1-4 pg/g hair and 3-13 pg/g hair, respectively. The method limit of quantification (LOQm) ranged between 6 and 301 pg/g hair. The PFAS levels were measured in 30 human hair samples indicating that the levels are low (14-1534 pg/g hair). Some PFAS were not present in any hair sample (e.g. PFHpA, PFTeDA, PFNA, PFPeS, PFHpS, PFOS and PFNS), while other PFAS were frequently detected (PFBA, PFPeA, PFHxA, PFOA, PFBS, PFHxS, PFOS, PFDS and PFDoS) in human hair. Although levels in general were low, there is evidence of higher human exposure to some analytes, such as PFBA

  18. New approach for assessing human perfluoroalkyl exposure via hair.

    PubMed

    Alves, Andreia; Jacobs, Griet; Vanermen, Guido; Covaci, Adrian; Voorspoels, Stefan

    2015-11-01

    In the recent years hair has been increasingly used as alternative matrix in human biomonitoring (HBM) of environmental pollutants. Sampling advantages and time integration of exposure assessment seems the most attractive features of hair matrix. In the current study, a novel miniaturized method was developed and validated for measuring 15 perfluoroalkyl substances (PFAS), including perfluoro n-butanoic acid (PFBA), perfluoro n-pentanoic acid (PFPeA), perfluoro n-hexanoic acid (PFHxA), perfluoro n-heptanoic acid (PFHpA), perfluor n-octanoic acid (PFOA), perfluoro n-nonanoic acid (PFNA), perfluoro tetradecanoic acid (PFTeDA), perfluorobutane sulfonic acid (PFBS), perfluoro pentane sulfonic acid (PFPeS), perfluorohexane sulfonic acid (PFHxS), perfluoroheptane sulfonic acid (PFHpS), perfluorooctane sulfonic acid (PFOS), perfluorononane sulfonic acid (PFNS), perfluorodecane sulfonic acid (PFDS) and perfluorododecane sulfonic acid (PFDoS) in human hair by liquid chromatography tandem mass spectrometry (LC-MS/MS). After extraction using ethyl acetate, dispersive ENVI-Carb was used for clean-up. Good intra- and inter-day precision for low (LQ 5 ng/g hair) and high spike (HQ 15n g/g) levels were achieved (in general RSD <10%). The accuracy was assessed using recoveries (%), which ranged between 68-118% (LQ) and 70-121% (HQ). The instrumental limit of detection (LODi) and limit of quantification (LOQi) were between 1-4 pg/g hair and 3-13 pg/g hair, respectively. The method limit of quantification (LOQm) ranged between 6 and 301 pg/g hair. The PFAS levels were measured in 30 human hair samples indicating that the levels are low (14-1534 pg/g hair). Some PFAS were not present in any hair sample (e.g. PFHpA, PFTeDA, PFNA, PFPeS, PFHpS, PFOS and PFNS), while other PFAS were frequently detected (PFBA, PFPeA, PFHxA, PFOA, PFBS, PFHxS, PFOS, PFDS and PFDoS) in human hair. Although levels in general were low, there is evidence of higher human exposure to some analytes, such as PFBA

  19. A PROPOSED FRAMEWORK FOR ASSESSING RISK FROM LESS-THAN-LIFETIME EXPOSURES TO CARCINOGENS

    EPA Science Inventory

    Quantitative cancer risk assessment methods have been developed for daily, lifetime human exposures, but not for exposures that are less than lifetime. Few examples for less-than-Iifetime exposures exist in the published literature. To move cancer risk assessment beyond reliance ...

  20. Assessment of outdoor radiofrequency electromagnetic field exposure through hotspot localization using kriging-based sequential sampling.

    PubMed

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

    2013-10-01

    In this study, a novel methodology is proposed to create heat maps that accurately pinpoint the outdoor locations with elevated exposure to radiofrequency electromagnetic fields (RF-EMF) in an extensive urban region (or, hotspots), and that would allow local authorities and epidemiologists to efficiently assess the locations and spectral composition of these hotspots, while at the same time developing a global picture of the exposure in the area. Moreover, no prior knowledge about the presence of radiofrequency radiation sources (e.g., base station parameters) is required. After building a surrogate model from the available data using kriging, the proposed method makes use of an iterative sampling strategy that selects new measurement locations at spots which are deemed to contain the most valuable information-inside hotspots or in search of them-based on the prediction uncertainty of the model. The method was tested and validated in an urban subarea of Ghent, Belgium with a size of approximately 1 km2. In total, 600 input and 50 validation measurements were performed using a broadband probe. Five hotspots were discovered and assessed, with maximum total electric-field strengths ranging from 1.3 to 3.1 V/m, satisfying the reference levels issued by the International Commission on Non-Ionizing Radiation Protection for exposure of the general public to RF-EMF. Spectrum analyzer measurements in these hotspots revealed five radiofrequency signals with a relevant contribution to the exposure. The radiofrequency radiation emitted by 900 MHz Global System for Mobile Communications (GSM) base stations was always dominant, with contributions ranging from 45% to 100%. Finally, validation of the subsequent surrogate models shows high prediction accuracy, with the final model featuring an average relative error of less than 2dB (factor 1.26 in electric-field strength), a correlation coefficient of 0.7, and a specificity of 0.96.

  1. Assessment of human exposure to chemicals from Superfund sites.

    PubMed Central

    Kamrin, M A; Fischer, L J; Suk, W A; Fouts, J R; Pellizzari, E; Thornton, K

    1994-01-01

    Assessing human exposure to chemicals from Superfund sites requires knowledge of basic physical, chemical, and biological processes occurring in the environment and specific information about the local environment and population in the vicinity of sites of interest. Although progress is being made in both areas, there is still a tremendous amount to be done. Participants at this meeting have identified several of the areas in need of greater understanding, and they are listed below. Movement of dissolved and volatile organics, especially NAPLs, in the subsurface environment. This includes study of the partitioning of compounds between NAPLs, air, water, and soil. Partitioning of volatilized chemicals between gaseous and aerosol components of the atmosphere. This includes understanding how these components influence both wet and dry deposition. Long-term movement from sediments into biota and how these affect chronic toxicity to sediment biota. Broad validation of PBPK models describing partitioning of compounds from sediment and water into fish. Reactions of chemicals sorbed to atmospheric particles. This includes application of laboratory models to real and varied atmospheric conditions. Interactions between biotic and abiotic transformations in soil and sediment. Applicability of physiological pharmacokinetic models developed in laboratory studies of experimental animals and clinical investigations of humans to environmental chemicals, concentrations, and routes of exposure in humans. Use of human and wildlife behavioral and biomonitoring information to estimate exposure. This includes better understanding of human variability and the applicability of information gathered from particular wildlife species. To successfully address these gaps in our knowledge, much more analytical data must be collected.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8187712

  2. KREAM: Korean Radiation Exposure Assessment Model for Aviation Route Dose

    NASA Astrophysics Data System (ADS)

    Hwang, J.; Dokgo, K.; Choi, E. J.; Kim, K. C.; Kim, H. P.; Cho, K. S. F.

    2014-12-01

    Since Korean Air has begun to use the polar route from Seoul/ICN airport to New York/JFK airport on August 2006, there are explosive needs for the estimation and prediction against cosmic radiation exposure for Korean aircrew and passengers in South Korea from public. To keep pace with those needs of public, Korean government made the law on safety standards and managements of cosmic radiation for the flight attendants and the pilots in 2013. And we have begun to develop our own Korean Radiation Exposure Assessment Model (KREAM) for aviation route dose since last year funded by Korea Meteorological Administration (KMA). GEANT4 model and NRLMSIS 00 model are used for calculation of the energetic particles' transport in the atmosphere and for obtaining the background atmospheric neutral densities depending on altitude. For prediction the radiation exposure in many routes depending on the various space weather effects, we constructed a database from pre-arranged simulations using all possible combinations of R, S, and G, which are the space weather effect scales provided by the National Oceanic and Atmospheric Administration (NOAA). To get the solar energetic particles' spectrum at the 100 km altitude which we set as a top of the atmospheric layers in the KREAM, we use ACE and GOES satellites' proton flux observations. We compare the results between KREAM and the other cosmic radiation estimation programs such as CARI-6M which is provided by the Federal Aviation Agency (FAA). We also validate KREAM's results by comparison with the measurement from Liulin-6K LET spectrometer onboard Korean commercial flights and Korean Air Force reconnaissance flights.

  3. Assessment of dust sampling methods for the study of cultivable-microorganism exposure in stables.

    PubMed

    Normand, Anne-Cécile; Vacheyrou, Mallory; Sudre, Bertrand; Heederik, Dick J J; Piarroux, Renaud

    2009-12-01

    Studies have shown a link between living on a farm, exposure to microbial components (e.g., endotoxins or beta-d-glucans), and a lower risk for allergic diseases and asthma. Due to the lack of validated sampling methods, studies of asthma and atopy have not relied on exposure assessment based on culture techniques. Our objective was therefore to compare several dust sampling methods for the detection of cultivable-microorganism exposure in stables. Sixteen French farms were sampled using four different methods: (i) active air sampling using a pump, (ii) passive dust sampling with a plastic box, (iii) dust sampling with an electrostatic dust fall collector (wipe), and (iv) dust sampling using a spatula to collect dust already settled on a windowsill. The results showed that collection of settled dust samples with either plastic boxes or wipes was reproducible (pairwise correlations, 0.72 and 0.73, respectively) and resulted in highly correlated results (pairwise correlation between the two methods, 0.82). We also found that settled dust samples collected with a plastic box correctly reflected the composition of the samples collected in the air of the stable when there was no farmer activity. A loss of microbial diversity was observed when dust was kept for 3 months at room temperature. We therefore conclude that measurement of viable microorganisms within a reasonable time frame gives an accurate representation of the microbial composition of stable air.

  4. Visual Risk Assessment of Space Radiation Exposure for Future Space Exploration Missions

    NASA Technical Reports Server (NTRS)

    Hussein, Hesham F.; Kim, Myung-Hee; Cucinotta, Francis A.

    2006-01-01

    Protecting astronauts from space radiation exposure during an interplanetary mission is an important challenge for mission design and operations. If sufficient protection is not provided near solar maximum, the risk can be significant due to exposure to sporadic solar particle events (SPEs) as well as to the continuous galactic cosmic radiation (GCR). Polyethylene shielded "storm shelters" inside spacecraft have been shown to limit total exposure from a large SPE to a permissible level, preventing acute risks and providing a potential approach to fulfill the ALARA (as low as reasonably achievable) requirement. For accurate predictions of radiation dose to astronauts involved in future space exploration missions, detailed variations of radiation shielding properties are required. Radiation fluences and doses vary considerably across both the spacecraft geometry and the body-shielding distribution. A model using a modern CAD tool ProE(TradeMark), which is the leading engineering design platform at NASA, has been developed to account for these local variations in the radiation distribution. Visual assessment of radiation distribution at different points inside a spacecraft module and in the human body for a given radiation environment are described. Results will ultimately guide in developing requirements for maximal protection for astronauts from space radiation.

  5. Assessment of planctomycetes cell viability after pollutants exposure.

    PubMed

    Flores, Carlos; Catita, José A M; Lage, Olga Maria

    2014-08-01

    In this study, the growth of six different planctomycetes, a particular ubiquitous bacterial phylum, was assessed after exposure to pollutants. In addition and for comparative purposes, Pseudomonas putida, Escherichia coli and Vibrio anguillarum were tested. Each microorganism was exposed to several concentrations of 21 different pollutants. After exposure, bacteria were cultivated using the drop plate method. In general, the strains exhibited a great variation of sensitivity to pollutants in the order: V. anguillarum > planctomycetes > P. putida > E. coli. E. coli showed resistance to all pollutants tested, with the exception of phenol and sodium azide. Copper, Ridomil® (fungicide), hydrazine and phenol were the most toxic pollutants. Planctomycetes were resistant to extremely high concentrations of nitrate, nitrite and ammonium but they were the only bacteria sensitive to Previcur N® (fungicide). Sodium azide affected the growth on plates of E. coli, P. putida and V. anguillarum, but not of planctomycetes. However, this compound affected planctomycetes cell respiration but with less impact than in the aforementioned bacteria. Our results provide evidence for a diverse response of bacteria towards pollutants, which may influence the structuring of microbial communities in ecosystems under stress, and provide new insights on the ecophysiology of planctomycetes.

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

    PubMed

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

    2006-11-01

    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 mgkg(-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.

  7. Personalized Cancer Risk Assessments for Space Radiation Exposures.

    PubMed

    Locke, Paul A; Weil, Michael M

    2016-01-01

    Individuals differ in their susceptibility to radiogenic cancers, and there is evidence that this inter-individual susceptibility extends to HZE ion-induced carcinogenesis. Three components of individual risk: sex, age at exposure, and prior tobacco use, are already incorporated into the NASA cancer risk model used to determine safe days in space for US astronauts. Here, we examine other risk factors that could potentially be included in risk calculations. These include personal and family medical history, the presence of pre-malignant cells that could undergo malignant transformation as a consequence of radiation exposure, the results from phenotypic assays of radiosensitivity, heritable genetic polymorphisms associated with radiosensitivity, and postflight monitoring. Inclusion of these additional risk or risk reduction factors has the potential to personalize risk estimates for individual astronauts and could influence the determination of safe days in space. We consider how this type of assessment could be used and explore how the provisions of the federal Genetic Information Non-discrimination Act could impact the collection, dissemination and use of this information by NASA. PMID:26942127

  8. Assessing exposure to cosmic radiation on board aircraft.

    PubMed

    Bottollier-Depois, J F; Chau, Q; Bouisset, P; Kerlau, G; Plawinski, L; Lebaron-Jacobs, L

    2003-01-01

    The assessment of exposure to cosmic radiation on board aircraft is one of the preoccupations of organizations responsible for radiation protection. The cosmic radiation particle flux increases with altitude and latitude and depends on the solar activity. The radiation exposure has been estimated on several airlines using transatlantic, Siberian and transequatorial routes on board subsonic and supersonic aircraft, to illustrate the effect of these parameters. Measurements have been obtained with a tissue equivalent proportional counter using the microdosimetric technique. Data have been collected at maximum solar activity in 1991-92 and at minimum in 1996-98. The lowest mean dose rate measured was 3 microSv/h during a Paris-Buenos Aires flight in 1991; the highest was 6.6 microSv/h during a Paris-Tokyo flight using a Siberian route and 9.7 microSv/h on Concorde in 1996-97. The mean quality factor is around 1.8. The corresponding annual effective dose, based on 700 hours of flight for subsonic aircraft and 300 hours for Concorde, can be estimated between 2 mSv for least-exposed routes and 5 mSv for more exposed routes.

  9. Personalized Cancer Risk Assessments for Space Radiation Exposures

    PubMed Central

    Locke, Paul A.; Weil, Michael M.

    2016-01-01

    Individuals differ in their susceptibility to radiogenic cancers, and there is evidence that this inter-individual susceptibility extends to HZE ion-induced carcinogenesis. Three components of individual risk: sex, age at exposure, and prior tobacco use, are already incorporated into the NASA cancer risk model used to determine safe days in space for US astronauts. Here, we examine other risk factors that could potentially be included in risk calculations. These include personal and family medical history, the presence of pre-malignant cells that could undergo malignant transformation as a consequence of radiation exposure, the results from phenotypic assays of radiosensitivity, heritable genetic polymorphisms associated with radiosensitivity, and postflight monitoring. Inclusion of these additional risk or risk reduction factors has the potential to personalize risk estimates for individual astronauts and could influence the determination of safe days in space. We consider how this type of assessment could be used and explore how the provisions of the federal Genetic Information Non-discrimination Act could impact the collection, dissemination and use of this information by NASA. PMID:26942127

  10. Organic dust exposures from compost handling: case presentation and respiratory exposure assessment.

    PubMed

    Weber, S; Kullman, G; Petsonk, E; Jones, W G; Olenchock, S; Sorenson, W; Parker, J; Marcelo-Baciu, R; Frazer, D; Castranova, V

    1993-10-01

    Inhalation of dust from contaminated organic materials may result in acute respiratory tract illness. Possible mechanisms include toxic and cellular reactions to microbial and other organic products or immunologic responses after prior sensitization to an antigen. A case is presented of a 52 year old male who developed fever, myalgia, and marked dyspnea 12 hr after shoveling composted wood chips and leaves. Inspiratory crackles, hypoxemia, and bilateral patchy pulmonary infiltrates were seen. Precipitating antibody tests for the usual antigens were inconclusive. He improved over 3 days. In order to assess the environmental conditions the patient had experienced, we returned to the site to reproduce and measure respiratory exposures during hand loading of the compost. Visible clouds of fine particulate were easily generated during handling activities. Microscopic examination of these dusts indicated a predominance of spores. Endotoxin concentrations from inspirable and respirable dust samples ranged from 636 to 16,300 endotoxin units/m3. Levels of contaminants found were consistent with those associated with respiratory illness in other agricultural settings. Two respiratory disorders, hypersensitivity pneumonitis (HP) and organic dust toxic syndrome (ODTS), may occur after exposure to organic dusts containing fungal spores and endotoxins. Despite extensive clinical and environmental investigations, we were unable to differentiate these two disorders, and suggest they may represent parts of a spectrum of responses to complex organic dusts, rather than completely distinct clinical entities.

  11. A risk assessment framework for assessing metallic nanomaterials of environmental concern: aquatic exposure and behavior.

    PubMed

    O'Brien, Niall Joseph; Cummins, Enda J

    2011-05-01

    Nanomaterials are finding application in many different environmentally relevant products and processes due to enhanced catalytic, antimicrobial, and oxidative properties of materials at this scale. As the market share of nano-functionalized products increases, so too does the potential for environmental exposure and contamination. This study presents some exposure ranking methods that consider potential metallic nanomaterial surface water exposure and fate, due to nano-functionalized products, through a number of exposure pathways. These methods take into account the limited and disparate data currently available for metallic nanomaterials and apply variability and uncertainty principles, together with qualitative risk assessment principles, to develop a scientific ranking. Three exposure scenarios with three different nanomaterials were considered to demonstrate these assessment methods: photo-catalytic exterior paint (nano-scale TiO₂), antimicrobial food packaging (nano-scale Ag), and particulate-reducing diesel fuel additives (nano-scale CeO₂). Data and hypotheses from literature relating to metallic nanomaterial aquatic behavior (including the behavior of materials that may relate to nanomaterials in aquatic environments, e.g., metals, pesticides, surfactants) were used together with commercial nanomaterial characteristics and Irish natural aquatic environment characteristics to rank the potential concentrations, transport, and persistence behaviors within subjective categories. These methods, and the applied scenarios, reveal where data critical to estimating exposure and risk are lacking. As research into the behavior of metallic nanomaterials in different environments emerges, the influence of material and environmental characteristics on nanomaterial behavior within these exposure- and risk-ranking methods may be redefined on a quantitative basis.

  12. Prenatal alcohol exposure: An assessment strategy for the legal context.

    PubMed

    Brown, Natalie Novick; Burd, Larry; Grant, Therese; Edwards, William; Adler, Richard; Streissguth, Ann

    2015-01-01

    Studies over the last two decades have shown that people with fetal alcohol spectrum disorders (FASD) have the kind of brain damage that increases risk of criminal behavior. Thus, it is generally accepted that FASD is likely to affect a sizable minority of individuals involved in the justice system. Most of these defendants have never been diagnosed because they lack the facial abnormalities and severe intellectual deficiency that would have improved identification and diagnosis in childhood. Despite the fact that an FASD diagnosis and associated cognitive deficits may be directly relevant to offense conduct and post-arrest capacities, screening for prenatal alcohol exposure (PAE) by legal teams remains relatively rare. This article addresses the relatively straightforward screening process with strategies that may be used singly or in combination to produce information that can establish PAE and provide a foundation for diagnostic assessment by medical and mental health experts. PMID:26338492

  13. {sup 125}I Measurements for Occupational Exposure Assessment

    SciTech Connect

    Silva, L.; Pinhao, N. R.

    2008-08-14

    Whenever there is a risk of occupational exposure to dispersible radioactive material, it is necessary to have a monitoring program to assess the effective dose arising from the intake of radionuclides by workers. In this paper we present our experience in bioassay measurements of {sup 125}I in urine samples of workers using high resolution gamma spectrometry. For a 24-hour excretion period, we found activity values of the order of one Bq and estimated the committed effective doses to be less than one {mu}Sv. Although very small, these values led to a re-evaluation and improvement of the laboratory safety conditions. We discuss the calibration procedure followed for the activity measurements, the estimation of the uncertainty in the excreted activity, the calculation of detection and quantification limits and estimation of performance indicators. Aspects regarding the spectral analysis, true coincidence summing and matrix effects are also considered.

  14. 21st Century Lunar Exploration: Advanced Radiation Exposure Assessment

    NASA Technical Reports Server (NTRS)

    Anderson, Brooke; Clowdsley, Martha; Wilson, John; Nealy, John; Luetke, Nathan

    2006-01-01

    On January 14, 2004 President George W Bush outlined a new vision for NASA that has humans venturing back to the moon by 2020. With this ambitious goal, new tools and models have been developed to help define and predict the amount of space radiation astronauts will be exposed to during transit and habitation on the moon. A representative scenario is used that includes a trajectory from LEO to a Lunar Base, and simplified CAD models for the transit and habitat structures. For this study galactic cosmic rays, solar proton events, and trapped electron and proton environments are simulated using new dynamic environment models to generate energetic electron, and light and heavy ion fluences. Detailed calculations are presented to assess the human exposure for transit segments and surface stays.

  15. Prenatal alcohol exposure: An assessment strategy for the legal context.

    PubMed

    Brown, Natalie Novick; Burd, Larry; Grant, Therese; Edwards, William; Adler, Richard; Streissguth, Ann

    2015-01-01

    Studies over the last two decades have shown that people with fetal alcohol spectrum disorders (FASD) have the kind of brain damage that increases risk of criminal behavior. Thus, it is generally accepted that FASD is likely to affect a sizable minority of individuals involved in the justice system. Most of these defendants have never been diagnosed because they lack the facial abnormalities and severe intellectual deficiency that would have improved identification and diagnosis in childhood. Despite the fact that an FASD diagnosis and associated cognitive deficits may be directly relevant to offense conduct and post-arrest capacities, screening for prenatal alcohol exposure (PAE) by legal teams remains relatively rare. This article addresses the relatively straightforward screening process with strategies that may be used singly or in combination to produce information that can establish PAE and provide a foundation for diagnostic assessment by medical and mental health experts.

  16. Assessment of carcinogenic risk from personal exposure to benzo(a)pyrene in the Total Human Environmental Exposure Study (THEES).

    PubMed

    Butler, J P; Post, G B; Lioy, P J; Waldman, J M; Greenberg, A

    1993-07-01

    The Total Human Environmental Exposure Study (THEES) was an investigation of multimedia exposure to the ubiquitous environmental carcinogen, benzo(a)pyrene (BaP). The three-phase study was conducted in Phillipsburg, New Jersey and involved the participation of 14-15 individuals (8-10 homes) during each 14-day monitoring period. Microenvironmental sampling of air, food, water and soil indicated that environmental exposure to BaP was primarily through air and food. Exposure and risk estimates were, therefore, based on the results of personal monitoring of breathing zone air and prepared food samples. Based on a comparison of the range and magnitude of inhalation and dietary BaP exposures, food ingestion was clearly the predominant exposure to pathway. The relative contributions of other potential sources of community exposure to BaP (e.g., soil and drinking water ingestion) were also assessed. The excess cancer risk estimates for food ingestion were consistently greater than those for personal air, reflecting both the predominantly higher BaP exposures through the diet and the higher carcinogenic potency value for oral exposure. Overall, the total lifetime risk from personal exposure to BaP for nonsmokers in the community was estimated at 10(-5). In identifying risk reduction options, it is important to account for the observation that personal activities, lifestyle, and diet strongly influenced individual exposures to BaP.

  17. Assessment of carcinogenic risk from personal exposure to benzo(a)pyrene in the Total Human Environmental Exposure Study (THEES)

    SciTech Connect

    Butler, J.P.; Post, G.B.; Lioy, P.J.; Waldman, J.M.; Greenberg, A. )

    1993-07-01

    The Total Human Environmental Exposure Study (THEES) was an investigation of multimedia exposure to the ubiquitous environmental carcinogen, benzo(a)pyrene (BaP). The three-phase study was conducted in Phillipsburg, New Jersey and involved the participation of 14-15 individuals (8-10 homes) during each 14-day monitoring period. Microenvironmental sampling of air, food, water and soil indicated that environmental exposure to BaP was primarily through air and food. Exposure and risk estimates were, therefore, based on the results of personal monitoring of breathing zone air and prepared food samples. Based on a comparison of the range and magnitude of inhalation and dietary BaP exposures, food ingestion was clearly the predominant exposure to pathway. The relative contributions of other potential sources of community exposure to BaP (e.g., soil and drinking water ingestion) were also assessed. The excess cancer risk estimates for food ingestion were consistently greater than those for personal air, reflecting both the predominantly higher BaP exposures through the diet and the higher carcinogenic potency value for oral exposure. Overall, the total lifetime risk from personal exposure to BaP for nonsmokers in the community was estimated at 10(-5). In identifying risk reduction options, it is important to account for the observation that personal activities, lifestyle, and diet strongly influenced individual exposures to BaP.

  18. Deoxynivalenol Exposure Assessment for Pregnant Women in Bangladesh.

    PubMed

    Ali, Nurshad; Blaszkewicz, Meinolf; Al Nahid, Abdullah; Rahman, Mustafizur; Degen, Gisela H

    2015-10-01

    The trichothecene mycotoxin deoxynivalenol (DON) is a contaminant of crops worldwide and known to cause adverse health effects in exposed animals and humans. A small survey reported the presence of DON in maize samples in Bangladesh, but these data are insufficient to assess human exposure, and also, biomonitoring data are still scarce. The present study applied biomarker analysis to investigate the DON exposure of pregnant women in Bangladesh. Urine samples were collected from pregnant women living in a rural (n = 32) and in a suburban (n = 22) area of the country. Urines were subjected to enzymatic hydrolysis of glucuronic acid conjugates and to immunoaffinity column clean-up prior to LC-MS/MS analysis of DON and its de-epoxy metabolite DOM-1. The limits of detection (LOD) for DON and DOM-1 in urine were 0.16 ng/mL and 0.10 ng/mL, respectively. DOM-1 was not detected in any of the urines, whilst DON was detectable in 52% of the samples at levels ranging from 0.18-7.16 ng/mL and a mean DON concentration of 0.86 ± 1.57 ng/mL or 2.14 ± 4.74 ng/mg creatinine. A significant difference in mean urinary DON levels was found between the rural (0.47 ± 0.73 ng/mL) and suburban (1.44 ± 2.20 ng/mL) cohort, which may be related to different food habits in the two cohorts. Analysis of food consumption data for the participants did not show significant correlations between their intake of typical staple foods and DON levels in urine. The biomarker concentrations found and published urinary excretion rates for DON were used to estimate daily mycotoxin intake in the cohort: the mean DON intake was 0.05 µg/kg b.w., and the maximum intake was 0.46 µg/kg b.w., values lower than the tolerable daily intake of 1 µg/kg b.w. These first results indicate a low dietary exposure of pregnant women in Bangladesh to DON. Nonetheless, further biomonitoring studies in children and in adult cohorts from other parts of the country are of interest to gain more insight into DON exposure in the

  19. Deoxynivalenol Exposure Assessment for Pregnant Women in Bangladesh

    PubMed Central

    Ali, Nurshad; Blaszkewicz, Meinolf; Nahid, Abdullah Al; Rahman, Mustafizur; Degen, Gisela H.

    2015-01-01

    The trichothecene mycotoxin deoxynivalenol (DON) is a contaminant of crops worldwide and known to cause adverse health effects in exposed animals and humans. A small survey reported the presence of DON in maize samples in Bangladesh, but these data are insufficient to assess human exposure, and also, biomonitoring data are still scarce. The present study applied biomarker analysis to investigate the DON exposure of pregnant women in Bangladesh. Urine samples were collected from pregnant women living in a rural (n = 32) and in a suburban (n = 22) area of the country. Urines were subjected to enzymatic hydrolysis of glucuronic acid conjugates and to immunoaffinity column clean-up prior to LC-MS/MS analysis of DON and its de-epoxy metabolite DOM-1. The limits of detection (LOD) for DON and DOM-1 in urine were 0.16 ng/mL and 0.10 ng/mL, respectively. DOM-1 was not detected in any of the urines, whilst DON was detectable in 52% of the samples at levels ranging from 0.18–7.16 ng/mL and a mean DON concentration of 0.86 ± 1.57 ng/mL or 2.14 ± 4.74 ng/mg creatinine. A significant difference in mean urinary DON levels was found between the rural (0.47 ± 0.73 ng/mL) and suburban (1.44 ± 2.20 ng/mL) cohort, which may be related to different food habits in the two cohorts. Analysis of food consumption data for the participants did not show significant correlations between their intake of typical staple foods and DON levels in urine. The biomarker concentrations found and published urinary excretion rates for DON were used to estimate daily mycotoxin intake in the cohort: the mean DON intake was 0.05 µg/kg b.w., and the maximum intake was 0.46 µg/kg b.w., values lower than the tolerable daily intake of 1 µg/kg b.w. These first results indicate a low dietary exposure of pregnant women in Bangladesh to DON. Nonetheless, further biomonitoring studies in children and in adult cohorts from other parts of the country are of interest to gain more insight into DON exposure in

  20. Radon exposure assessment in a former uranium production facility

    SciTech Connect

    Akbar-Khanzadch, F.; Merrill, E.A.

    1996-06-01

    Storage of radon-producing materials in three silos and six waste pits is one of the major environmental and occupational issues at a former uranium production facility, now a Superfund Site. The concentrations of radium up to 190,000 pCi g{sup -1} for silos and up to 1,200 pCi g{sup -1} for waste pits have been reported. This study was conducted to identify conditions and climatic factors that contribute to higher radon levels and to assess workers` exposure at the site. Data covering a 12-mo period were compiled from monitoring radon levels by hourly real-time indoor (within 3 buildings) and outdoor (at 14 on-site and 2 off-site stations) and from hourly site specific meteorological information. The ranges of radon levels were 0.05-98.8 pCi L{sup -1} outdoor on-site, 0.1-8.9 pCi L{sup -1} outdoor off-side, and 0.05-3.0 pCi L{sup -1} indoor on-site. Only radon levels in the vicinity of the storage silos, which is an exclusion zone, were significantly higher than levels off-site. Significantly higher levels of radon were detected in the production areas vs. those at the perimeter areas, suggesting that there were significant sources of on-site radon contamination other than the silos. Radon concentrations showed diurnal variations, maximum levels occurring at early morning and minimum levels in the afternoon. A seasonal variation was also observed, with radon levels highest during mid summer while lowest during winter. Wind direction, wind speed, relative humidity, and ambient temperature appeared to be the most significant predictors of radon concentration. The dose, calculated by using exposure models and annual average levels of radon in the work area, was below recommended exposure limits. These results suggest that the emission control methods at this site have been effective in maintaining environmental radon contamination and workers` exposure at acceptable levels.

  1. Deoxynivalenol Exposure Assessment for Pregnant Women in Bangladesh.

    PubMed

    Ali, Nurshad; Blaszkewicz, Meinolf; Al Nahid, Abdullah; Rahman, Mustafizur; Degen, Gisela H

    2015-09-24

    The trichothecene mycotoxin deoxynivalenol (DON) is a contaminant of crops worldwide and known to cause adverse health effects in exposed animals and humans. A small survey reported the presence of DON in maize samples in Bangladesh, but these data are insufficient to assess human exposure, and also, biomonitoring data are still scarce. The present study applied biomarker analysis to investigate the DON exposure of pregnant women in Bangladesh. Urine samples were collected from pregnant women living in a rural (n = 32) and in a suburban (n = 22) area of the country. Urines were subjected to enzymatic hydrolysis of glucuronic acid conjugates and to immunoaffinity column clean-up prior to LC-MS/MS analysis of DON and its de-epoxy metabolite DOM-1. The limits of detection (LOD) for DON and DOM-1 in urine were 0.16 ng/mL and 0.10 ng/mL, respectively. DOM-1 was not detected in any of the urines, whilst DON was detectable in 52% of the samples at levels ranging from 0.18-7.16 ng/mL and a mean DON concentration of 0.86 ± 1.57 ng/mL or 2.14 ± 4.74 ng/mg creatinine. A significant difference in mean urinary DON levels was found between the rural (0.47 ± 0.73 ng/mL) and suburban (1.44 ± 2.20 ng/mL) cohort, which may be related to different food habits in the two cohorts. Analysis of food consumption data for the participants did not show significant correlations between their intake of typical staple foods and DON levels in urine. The biomarker concentrations found and published urinary excretion rates for DON were used to estimate daily mycotoxin intake in the cohort: the mean DON intake was 0.05 µg/kg b.w., and the maximum intake was 0.46 µg/kg b.w., values lower than the tolerable daily intake of 1 µg/kg b.w. These first results indicate a low dietary exposure of pregnant women in Bangladesh to DON. Nonetheless, further biomonitoring studies in children and in adult cohorts from other parts of the country are of interest to gain more insight into DON exposure in the

  2. Improving Exposure Science and Dose Metrics for Toxicity Testing, Screening, Prioritizing, and Risk Assessment

    EPA Science Inventory

    Advance the characterization of exposure and dose metrics required to translate advances and findings in computational toxicology to information that can be directly used to support exposure and risk assessment for decision making and improved public health.

  3. ASSESSING POPULATION EXPOSURES TO MULTIPLE AIR POLLUTANTS USING A MECHANISTIC SOURCE-TO-DOSE MODELING FRAMEWORK

    EPA Science Inventory

    The Modeling Environment for Total Risks studies (MENTOR) system, combined with an extension of the SHEDS (Stochastic Human Exposure and Dose Simulation) methodology, provide a mechanistically consistent framework for conducting source-to-dose exposure assessments of multiple pol...

  4. ARE ALL ARSENIC EXPOSURES TOXIC? SUPPORTING REGIONAL RISK ASSESSMENTS THROUGH IMPROVED ARSENIC SPECIATION METHODOLOGY

    EPA Science Inventory

    Arsenic exposure assessments require the evaluation of the relative contribution of both media (water, food, etc.) and routes of exposure (ingestion, inhalation, dermal). For arsenic, the important media are predominately water and food and therefore, the route of concern for ...

  5. Exposure to o-toluidine, aniline, and nitrobenzene in a rubber chemical manufacturing plant: a retrospective exposure assessment update.

    PubMed

    Hanley, Kevin W; Viet, Susan M; Hein, Misty J; Carreón, Tania; Ruder, Avima M

    2012-01-01

    The National Institute for Occupational Safety and Health previously conducted a retrospective cancer incidence and mortality study of workers employed at a rubber chemical manufacturing plant. Compared with New York State incidence, the bladder cancer risk was 6.5 times higher for workers considered to have definite exposure to ortho-toluidine and aniline, and 4 times higher for workers with possible exposure. Exposure characterization in the original study utilized a surrogate measure based only on departments in which each worker was ever employed. As part of an update of that study, some departments in the three original exposure groups were reclassified based on a follow-up site visit; interviews with employees, management, and union representatives; and review of records including exposure data. An additional evaluation of department-job combinations, rather than only departments, was used to stratify exposure into four categories. An approximate rank of "relative" exposure level for each department-job-year combination was also assigned using a ranking scale of 0 to 10. The ranks were supported by quantitative exposure levels and by professional judgment. The numerical ranking scale was applied to each worker by multiplying the exposure rank by duration for each job held based on comprehensive individual work histories. The cumulative rank scores for this cohort ranged from 0 to 300 unit-years. The medians of the cumulative rank scores for the exposure categories showed very good agreement with increasing exposure classifications (e.g., 0.72, 4.6, 11, 14 unit-years for the four exposure categories). Workers' breathing zone air sampling data collected at this plant from 1976-2004 were well below published occupational exposure limits for these chemicals, but additional cases of bladder cancer have been reported. The exposure assessment revisions and rank estimates will be used to analyze the updated bladder cancer incidence data.

  6. Characterizing Aerosolized Particulate As Part Of A Nanoprocess Exposure Assessment

    SciTech Connect

    Jankovic, John Timothy; Ogle, Burton R; Zontek, Tracy L; Hollenbeck, Scott M

    2010-01-01

    The purpose of this effort was to propose important aerosol characterization parameters that should be gathered as part of a nanomaterial hazard assessment and to offer a methodology for applying that data to daily operations. This study documents different ways of characterizing nanoscale materials using an aerosol from a process simulation consisting of a vacuum cleaner motor operating inside an enclosure. The aerosol is composed of insoluble carbon particles plus environmental background constituents. The average air concentration is 2.76E+5 p/cm3. Size measurements of the aerosol indicate > 70% of the particulate is blade-like in shape, 50% of which have a height dimension 100 nm. In terms of an equivalent spherical diameter 0.8% of the particulate is 100 nm in size. The carbon blades are characterized as having a root-mean-square roughness of 75 nm, and average fractal dimension of 2.25. These measures: aerosol chemistry, solubility, shape and size, surface area, number concentration and size distribution are important parameters to collect for current exposure assessment and toxicology and epidemiology studies.

  7. Toxicological evaluation of complex industrial wastes: Implications for exposure assessment

    SciTech Connect

    DeMarini, D.M.; Gallagher, J.E.; Houk, V.S.; Simmons, J.E.

    1990-07-01

    We evaluated a variety of short-term bioassays to construct a battery of tests that could be used for assessing the biological effects of potentially hazardous complex industrial wastes. Ten samples were studied for hepatotoxicity; these samples and an additional five were studied for mutagenicity. Although the data are limited to these samples, the results suggest that the Salmonella assay (strain TA98) or a prophage-induction assay (both in the presence of S9) in combination with determination of relative liver weight and levels of a set of serum enzymes in rats may provide a battery of tests suitable to characterize complex industrial wastes for mutagenic and hepatotoxic potential. The biological activities exhibited by the wastes were not readily predicted by the chemical profiles of the wastes, emphasizing the importance of characterizing potentially hazardous complex industrial wastes by both chemical and biological means. DNA from liver, lung, and bladder of rats exposed to some of the wastes was analyzed by the 32P-postlabeling technique for the presence of DNA adducts. A waste that produced mutagenic urine produced a DNA adduct in bladder DNA. The implications of this approach for assessment of exposure to complex hazardous waste mixtures are discussed.

  8. Exposure and risk assessment of zinc in Japanese surface waters.

    PubMed

    Naito, Wataru; Kamo, Masashi; Tsushima, Koji; Iwasaki, Yuichi

    2010-09-15

    In recent years, due to concerns on the potential effects of zinc on aquatic biota, zinc is receiving particular attention from regulatory agencies. A comprehensive exposure and risk assessment of zinc in Japanese surface waters was conducted to provide a scientific basis for developing realistic risk reduction measures for zinc. Emissions from corrosion contribute approximately 37% of the total zinc emissions to surface water in Japan. The zinc concentration distributions estimated using 12 years of monitoring data from 2075 sites by a maximum likelihood method indicated that the mean concentrations have gradually declined. The threshold concentrations (HC5 and PHC5) derived from organism- and population-level species sensitivity distributions were estimated to be 27 and 107 microg/L for total zinc, respectively. The risk characterization identified that during 1991-2002, 14.5-26.8% of the monitoring sites likely exceeded the HC5, whereas only 0.7-3.5% likely exceeded the PHC5. Evaluation of the effect of stormwater runoff to zinc concentrations in a river showed that zinc concentrations in river water increased significantly from roadway drainage flowing into the river. The cost-effectiveness analyses demonstrated that enforcement of the zinc national effluent standard may be effective at a certain level for public water areas in Japan; however, the degree of the effectiveness is highly dependent on the characteristics (e.g., sources and background) of the watersheds. An emissions and exposure assessment along with cost-effectiveness analysis is crucial for developing realistic and appropriate ecological risk management of zinc. The zinc RAD in Japan illustrated that in any "state-of-the science" method used, some degree of ecological risk from zinc can be observed in some Japanese water environments. On the other hand, zinc is a beneficial material for human industrial activities. Because zinc is an element, its role in industrial activities would be difficult

  9. ASSESSING ASTHMATIC CHILDREN'S EXPOSURES TO TOXIC AIR POLLUTANTS AND THE POTENTIAL INHALED DOSES USING TIME ACTIVITY INFORMATION AND ENERGY EXPENDITURE DATA

    EPA Science Inventory

    Accurately quantifying human exposures and the potential doses of various populations to environmental pollutants is critical for the U.S. Environmental Protection Agency to assess and manage human health risks. The Tampa Asthmatic Children's Study (TACS) was a pilot research stu...

  10. A hazardous substance exposure prevention rating method for intervention needs assessment and effectiveness evaluation: the Small Business Exposure Index

    PubMed Central

    2009-01-01

    Aims This paper describes the refinement and adaptation to small business of a previously developed method for systematically prioritizing needs for intervention on hazardous substance exposures in manufacturing worksites, and evaluating intervention effectiveness. Methods We developed a checklist containing six unique sets of yes/no variables organized in a 2 × 3 matrix of exposure potential versus exposure protection at three levels corresponding to a simplified hierarchy of controls: materials, processes, and human interface. Each of the six sets of indicator variables was reduced to a high/moderate/low rating. Ratings from the matrix were then combined to generate an exposure prevention 'Small Business Exposure Index' (SBEI) Summary score for each area. Reflecting the hierarchy of controls, material factors were weighted highest, followed by process, and then human interface. The checklist administered by an industrial hygienist during walk-through inspection (N = 149 manufacturing processes/areas in 25 small to medium-sized manufacturing worksites). One area or process per manufacturing department was assessed and rated. A second hygienist independently assessed 36 areas to evaluate inter-rater reliability. Results The SBEI Summary scores indicated that exposures were well controlled in the majority of areas assessed (58% with rating of 1 or 2 on a 6-point scale), that there was some room for improvement in roughly one-third of areas (31% of areas rated 3 or 4), and that roughly 10% of the areas assessed were urgently in need of intervention (rated as 5 or 6). Inter-rater reliability of EP ratings was good to excellent (e.g., for SBEI Summary scores, weighted kappa = 0.73, 95% CI 0.52–0.93). Conclusion The SBEI exposure prevention rating method is suitable for use in small/medium enterprises, has good discriminatory power and reliability, offers an inexpensive method for intervention needs assessment and effectiveness evaluation, and complements

  11. The Role of Arsenic Speciation in Dietary Exposure Assessment and the Need to Include Bioaccessibility and Biotransformation

    EPA Science Inventory

    Chemical form specific exposure assessment for arsenic has long been identified as a source of uncertainty in estimating the risk associated with the aggregate exposure for a population. Some speciation based assessments document occurrence within an exposure route; however, the...

  12. INNOVATIVE TOOLS AND METHODS FOR ASSESSING CHILDREN'S POTENTIAL CHEMICAL EXPOSURE

    EPA Science Inventory

    Children's exposures to environmental contaminants are different than adults, due in part to differences in physiologic functions. Research on children's exposure to environmental contaminants is currently being performed within EPA, academia, industry, and other research organi...

  13. ASSESSING SUSCEPTIBILITY FROM EARLY-LIFE EXPOSURE TO CARCINOGENS

    EPA Science Inventory

    Cancer risks from childhood exposures to chemicals are generally analyzed using methods based upon exposure from adults, which assumes chemicals are equally potent for inducing risks at these different lifestages. Published literature was evaluated to determine whether there was...

  14. INNOVATIVE APPROACHES TO HUMAN EXPOSURE ASSESSMENT IN ENVIRONMENTAL JUSTICE COMMUNITIES

    EPA Science Inventory

    North Carolina Central University (NCCU) recently began an innovative human exposure research program in collaboration with the U.S. Environmental Protection Agency's National Exposure Research Laboratory in Research Triangle Park, NC. In this project, researchers will examine ...

  15. Risk Assessment Strategies and Techniques for Combined Exposures

    EPA Science Inventory

    Author: Cynthia V. Rider, Ph.D., and Jane Ellen Simmons, Ph.D.Abstract: Consideration of cumulative risk is necessary to evaluate properly the safety of, and the risks associated with, combined exposures. These combined exposures ("mixtures") commonly occur from exposure to: envi...

  16. Guidelines for Exposure Assessment in Health Risk Studies Following a Nuclear Reactor Accident

    PubMed Central

    Bouville, André; Linet, Martha S.; Hatch, Maureen; Mabuchi, Kiyohiko

    2013-01-01

    Background: Worldwide concerns regarding health effects after the Chernobyl and Fukushima nuclear power plant accidents indicate a clear need to identify short- and long-term health impacts that might result from accidents in the future. Fundamental to addressing this problem are reliable and accurate radiation dose estimates for the affected populations. The available guidance for activities following nuclear accidents is limited with regard to strategies for dose assessment in health risk studies. Objectives: Here we propose a comprehensive systematic approach to estimating radiation doses for the evaluation of health risks resulting from a nuclear power plant accident, reflected in a set of seven guidelines. Discussion: Four major nuclear reactor accidents have occurred during the history of nuclear power production. The circumstances leading to these accidents were varied, as were the magnitude of the releases of radioactive materials, the pathways by which persons were exposed, the data collected afterward, and the lifestyle factors and dietary consumption that played an important role in the associated radiation exposure of the affected populations. Accidents involving nuclear reactors may occur in the future under a variety of conditions. The guidelines we recommend here are intended to facilitate obtaining reliable dose estimations for a range of different exposure conditions. We recognize that full implementation of the proposed approach may not always be feasible because of other priorities during the nuclear accident emergency and because of limited resources in manpower and equipment. Conclusions: The proposed approach can serve as a basis to optimize the value of radiation dose reconstruction following a nuclear reactor accident. Citation: Bouville A, Linet MS, Hatch M, Mabuchi K, Simon SL. 2014. Guidelines for exposure assessment in health risk studies following a nuclear reactor accident. Environ Health Perspect 122:1–5; http://dx.doi.org/10

  17. CHILDREN'S DIETARY EXPOSURES TO CHEMICAL CONTAMINANTS

    EPA Science Inventory

    The Food Quality Protection Act of 1996 requires EPA to more accurately assess children's aggregate exposures to environmental contaminants. Children have unstructured eating behaviors which cause excess exposures as a result of their activities. Determining total dietary intak...

  18. Pulmonary function in beryllium workers: assessment of exposure.

    PubMed Central

    Kriebel, D; Sprince, N L; Eisen, E A; Greaves, I A

    1988-01-01

    The inhalation of beryllium causes a serious lung disease characterised by pronounced radiographic and functional impairments and occurs in workers engaged in the extraction and manufacture of the metal. This paper describes the beryllium exposure levels and refining processes in a large beryllium factory operating since the 1930s. Lifetime beryllium exposure histories were estimated for the 309 workers present at a health survey conducted in 1977. Beryllium exposure levels in the plant were high for many years, with some estimated exposure levels in excess of 100 micrograms/m3. As late as 1975, there were exposures to beryllium above 10 micrograms/m3 in some jobs. After about 1977, the plant was in compliance with the permissible exposure limit of 2.0 micrograms/m3. The median cumulative exposure in this cohort was 65 micrograms/m3-years and the median duration of exposure was 17 years. From these data a series of exposure parameters, functions of the exposure histories that characterise biologically important dimensions of exposure were calculated for each worker. PMID:3342199

  19. International Symposia on Integrated Exposure Assessment for Hazardous Materials

    PubMed Central

    Kwon, Ho-Jang; Ha, Mina

    2012-01-01

    Objectives On September 2, 2010 and November 25, 2011, the Korean Research Project on Integrated Exposure Assessment to Hazardous Materials for Food Safety (KRIEFS) organized two international symposia in Seoul, Korea. KRIEFS, established by the Korean Food and Drug Administration in March 2010, envisioned these international symposia as means to obtain advanced experiences from other countries and to reflect on and refine the KRIEFS's survey design and methods. Methods For the first symposium KRIEFS invited human biomonitoring (HBM) experts from Germany, the US, and Canada. The visiting HBM experts shared the details of their national studies while the KRIEFS discussed study design, as well as the methods, results and policymaking processes of the KRIEFS project. The second symposium was organized to share the survey design and results on endocrine disruptors from Taiwan. Results The Speaker from Germany introduced the German Environmental Survey and shared their experiences in HBM design, such as the process of developing reference values, and discussed the new HBM plan in Germany and the European Union. The Representative from Canada shared insights from national HBM approach. In the case of the US, the speaker focused on risk communication with subjects in epidemiological studies. In the second international symposium, the speaker shared the experience of endocrine disruptors'studies from Taiwan. Conclusions KRIEFS was able to better understand previous nationwide HBM research designs, policy making process, and risk communication with research subjects.

  20. Physiologic assessment of fetal compromise: biomarkers of toxic exposure

    SciTech Connect

    Longo, L.D.

    1987-10-01

    Understanding the physiologic and endocrinologic basis of fetal development is a major goal of perinatal biology. During the past decade a number of technological developments have allowed more precise evaluation of the fetus in utero and diagnosis of abnormalities. Despite these methodological achievements, however, there are no specific biological markers currently available to indicate that exposure to a given xenobiotic is associated with a cellular, subcellular, or pharmacodynamic event. This paper evaluates the following issues: what are some of the unique physiologic and endocrinologic features of the fetal milieu interieur. What problems are peculiar to fetal assessment. What are some examples of validated biomarkers and their applicability. What promising biomarkers are on the horizon. How may molecular probes be of value as biological markers of fetal compromise. What are some of the major research gaps and needs, and how should research priorities be set. Some of these topics are addressed. Moreover, the more general role(s) that various diagnostic methods and biological markers can have in an understanding of the regulation of fetal growth and differentiation and the role of xenobiotics in affecting the normal course of events are discussed.

  1. Assessing host extinction risk following exposure to Batrachochytrium dendrobatidis.

    PubMed

    Louca, Stilianos; Lampo, Margarita; Doebeli, Michael

    2014-06-22

    Wildlife diseases are increasingly recognized as a major threat to biodiversity. Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungus Batrachochytrium dendrobatidis (Bd). Using a mathematical model and simulations, we study its effects on a generic riparian host population with a tadpole and adult life stage. An analytical expression for the basic reproduction quotient, Qo, of the pathogen is derived. By sampling the entire relevant parameter space, we perform a statistical assessment of the importance of all considered parameters in determining the risk of host extinction, upon exposure to Bd. We find that Qo not only gives a condition for the initial invasion of the fungus, but is in fact the best predictor for host extinction. We also show that the role of tadpoles, which in some species tolerate infections, is ambivalent. While tolerant tadpoles may provide a reservoir for the fungus, thus facilitating its persistence or even amplifying its outbreaks, they can also act as a rescue buffer for a stressed host population. Our results have important implications for amphibian conservation efforts.

  2. Assessing host extinction risk following exposure to Batrachochytrium dendrobatidis

    PubMed Central

    Louca, Stilianos; Lampo, Margarita; Doebeli, Michael

    2014-01-01

    Wildlife diseases are increasingly recognized as a major threat to biodiversity. Chytridiomycosis is an emerging infectious disease of amphibians caused by the fungus Batrachochytrium dendrobatidis (Bd). Using a mathematical model and simulations, we study its effects on a generic riparian host population with a tadpole and adult life stage. An analytical expression for the basic reproduction quotient, Qo, of the pathogen is derived. By sampling the entire relevant parameter space, we perform a statistical assessment of the importance of all considered parameters in determining the risk of host extinction, upon exposure to Bd. We find that Qo not only gives a condition for the initial invasion of the fungus, but is in fact the best predictor for host extinction. We also show that the role of tadpoles, which in some species tolerate infections, is ambivalent. While tolerant tadpoles may provide a reservoir for the fungus, thus facilitating its persistence or even amplifying its outbreaks, they can also act as a rescue buffer for a stressed host population. Our results have important implications for amphibian conservation efforts. PMID:24807247

  3. Exposure assessment of mycotoxins in cow's milk in Argentina.

    PubMed

    Signorini, M L; Gaggiotti, M; Molineri, A; Chiericatti, C A; Zapata de Basílico, M L; Basílico, J C; Pisani, M

    2012-02-01

    A stochastic simulation model was developed to carry out the first quantitative risk exposure assessment of the mycotoxin level in cow's milk produced in Argentina. The prevalence and concentration of aflatoxin M1 (AFM1), deoxynivalenol (DON) and zearalenone (ZEA) were modeled at various stages through milk processes complying with Argentinean practices. Concentration of AFM1 (0.059ppb), DON (0.338ppb) and ZEA (0.125ppb) in dairy milk were estimated. The proportion of feed samples that exceeded the maximum level accepted by European regulations for AFB1, DON and ZEA were estimated at 25.07%, 0.0% and 8.9%, respectively. The percentage of milk samples that exceeded the maximum level accepted for AFB1 by the MERCOSUR (0.5ppb) and the European Union regulations (0.05ppb) were 0.81 and 32.65, respectively. The probability distribution of AFM1 concentration in milk was affected by the carry-over rate equations applied in the model. Mycotoxin levels in corn silage and concentrated feeds were the factors most correlated with mycotoxin concentrations in milk. Therefore, agricultural practices, crop management and feed production require prompt attention regarding mycotoxin issues.

  4. Exposure Assessment of the Tehran Population (Iran) to Zearalenone Mycotoxin

    PubMed Central

    Yazdanpanah, Hassan; Zarghi, Afshin; Shafaati, Ali Reza; Foroutan, Seyyed Mohsen; Aboul-Fathi, Farshid; Khoddam, Arash; Nazari, Firoozeh

    2012-01-01

    Zearalenone (ZEA) mycotoxin is a potent estrogenic metabolite. It is the primary toxin causing infertility, abortion or other breeding problems. A HPLC method was validated for ZEA in foods using a monolithic column with sample clean-up on an immunoaffinity column. A certified reference material (CRM) from FAPAS (UK) was analyzed. A survey of ZEA was performed on the 72 samples of rice, bread, puffed corn snack and wheat flour collected from Tehran retail market. The average recovery and coefficient of variation in different foods ranged 92.7-107.1 and 4.9-13.8%, respectively. The amount of ZEA in corn CRM was in the acceptable range of FAPAS. The limit of quantification was 3 ng/g for rice, bread and wheat flour and 2.7 ng/g for puffed corn snack. The retention time of zearalenone was 2.6 min. All samples had contamination level lower than the maximum tolerated level of ZEA in foods in Iran. The mean intake of ZEA from all samples was much lower than the tolerable daily intake estimated by JECFA. This is the first survey on ZEA contamination in bread and rice in Iran as well as the first study on exposure assessment of Tehran population to ZEA. PMID:24250447

  5. APPLICATION OF THE EXPOSURE DOSE ESTIMATING MODEL (ERDEM) TO ASSESSMENT OF DERMAL EXPOSURE IN THE RAT TO MALATHION

    EPA Science Inventory

    APPLICATION OF THE EXPOSURE DOSE ESTIMATING MODEL (ERDEM) TO ASSESSMENT OF DERMAL EXPOSURE IN THE RAT TO MALATHION.
    Evans, M.V1., Power, F.W2., Dary, C.C2., Tornero-Velez, R2., and Blancato, J.N2.
    1 NHEERL, US EPA, ORD, ETD, RTP, NC; 2 NERL, US EPA, ORD, EDRB, LV, NV
    Re...

  6. CSF as a surrogate for assessing CNS exposure: an industrial perspective.

    PubMed

    Lin, Jiunn H

    2008-01-01

    For drugs that directly act on targets in the central nervous system (CNS), sufficient drug delivery into the brain is a prerequisite for drug action. Systemically administered drugs can reach CNS by passage across the endothelium of capillary vasculatures, the so-called blood-brain barrier (BBB). Literature data suggest that most marketed CNS drugs have good membrane permeability and relatively high plasma unbound fraction, but are not good P-glycoprotein (P-gp) substrates. Therefore, it is important to use the in vitro parameters of P-gp function activity, membrane permeability and plasma unbound fraction as key criteria for lead optimization during the early stage of drug discovery. Evidence from preclinical and clinical studies suggests that drug concentration in cerebrospinal fluid (CSF) appears to be reasonably accurate in predicting unbound drug concentration in the brain. Therefore, CSF can be used as a useful surrogate for in vivo assessment of CNS exposure and provides an important basis for the selection of drug candidates for entry into development. However, it is important to point out that CSF drug concentration is not always an accurate surrogate for predicting unbound drug concentration in the brain. Depending on the physicochemical properties of drugs and the site/timing of CSF sampling, the unbound drug concentration at the biophase within the brain could differ significantly from the corresponding CSF drug concentration.

  7. Review of methods applicable to the assessment of mold exposure to children.

    PubMed Central

    Dillon, H K; Miller, J D; Sorenson, W G; Douwes, J; Jacobs, R R

    1999-01-01

    This article presents discussion of the assessment of the exposure of children to fungi, substances derived from fungi, and the environmental conditions that may lead to exposure. The principles driving investigations of fungal contamination and subsequent exposure are presented as well as guidelines for conducting these investigations. A comprehensive description of available research sampling and analysis techniques is also presented. PMID:10423390

  8. Methodological Issues in Assessing the Impact of Prenatal Drug Exposure.

    PubMed

    Konijnenberg, Carolien

    2015-01-01

    Prenatal drug exposure is a common public health concern that can result in perinatal complications, birth defects, and developmental disorders. The growing literature regarding the effects of prenatal exposure to specific drugs such as tobacco, alcohol, cocaine, and heroin is often conflicting and constantly changing. This review discusses several reasons why the effects of prenatal drug exposure are so difficult to determine, including variations in dose, timing, duration of exposure, polydrug use, unreliable measures of drug exposure, latent or "sleeper" effects, genetic factors, and socioenvironmental influences. In addition to providing research guidelines, this review also aims to help clinicians and policy makers to identify the strengths and weaknesses in studies investigating the effects of prenatal drug exposure. This knowledge may be used to make better informed decisions regarding the appropriate treatment for pregnant, drug-dependent women and their children. PMID:26604776

  9. Methodological Issues in Assessing the Impact of Prenatal Drug Exposure

    PubMed Central

    Konijnenberg, Carolien

    2015-01-01

    Prenatal drug exposure is a common public health concern that can result in perinatal complications, birth defects, and developmental disorders. The growing literature regarding the effects of prenatal exposure to specific drugs such as tobacco, alcohol, cocaine, and heroin is often conflicting and constantly changing. This review discusses several reasons why the effects of prenatal drug exposure are so difficult to determine, including variations in dose, timing, duration of exposure, polydrug use, unreliable measures of drug exposure, latent or “sleeper” effects, genetic factors, and socioenvironmental influences. In addition to providing research guidelines, this review also aims to help clinicians and policy makers to identify the strengths and weaknesses in studies investigating the effects of prenatal drug exposure. This knowledge may be used to make better informed decisions regarding the appropriate treatment for pregnant, drug-dependent women and their children. PMID:26604776

  10. Assessment of multipathway exposure of small children to PAH.

    PubMed

    Vyskocil; Fiala; Chénier; Krajak; Ettlerova; Bukac; Viau; Emminger

    2000-01-01

    The aim of study was to assess the uptake of polycyclic aromatic hydrocarbons (PAH) by children living in a city and its effect on 1-hydroxypyrene (1-OHP) excretion. Two groups of children (n=11 and 13; 3-6 years old) were chosen: (1) a group from a kindergarten situated near a road with a high traffic density ('polluted' area); (2) a group from a kindergarten situated in a green zone ('non polluted' area). Food consumption was recorded in all children and PAH uptake from foodstuffs was estimated. Ambient air samples were collected on the playground and indoor of kindergartens during 3 days in summer 1997. Soil samples were collected on the playground. Urine samples were collected in the morning and in the evening. Mean outdoor total PAH concentration (sum of 12 individual PAH) in 'polluted' area was 12 times higher than that in 'non polluted' area (22.9 vs. 1.9 ng/m(3)). However, indoor concentrations were similar (3.0 vs. 2.1 ng/m(3)). The same trend was observed for pyrene concentrations. The contribution to the total pyrene absorbed dose from food consumption (estimated daily absorbed dose of 167 and 186 ng, respectively, in 'polluted' and 'non polluted' area) was much more important than that from inhalation (8.4 and 5.4 ng, respectively) in both areas. The estimated daily absorbed doses of pyrene from the soil were 0.061 and 0.104 ng in 'polluted' and 'non polluted' kindergarten, respectively, which correspond to 0.032 and 0.059% of the total absorbed dose. Higher urinary concentrations of 1-OHP were found in children from 'polluted' kindergarten. In conclusion, the food seems to be a main source of the total pyrene and total PAH uptake in small children, even under a relative high PAH air exposure in the city. Pyrene concentration in soil had a negligible contribution to the total pyrene absorbed dose. Usefulness of the urinary 1-OHP as an indicator of the environmental exposure to PAH needs further research.

  11. METHODOLOGY FOR THE EVALUATION OF CUMULATIVE EPISODIC EXPOSURE TO CHEMICAL STRESSORS IN AQUATIC RISK ASSESSMENT.

    EPA Science Inventory

    An ecological risk assessment method was developed to evaluate the magnitude, duration, and episodic nature of chemical stressors on aquatic communities. The percent of an ecosystem's species at risk from a designated chemical exposure scenario is generated. In effects assessment...

  12. Integrating smart-phone based momentary location tracking with fixed site air quality monitoring for personal exposure assessment.

    PubMed

    Su, Jason G; Jerrett, Michael; Meng, Ying-Ying; Pickett, Melissa; Ritz, Beate

    2015-02-15

    Epidemiological studies investigating relationships between environmental exposures from air pollution and health typically use residential addresses as a single point for exposure, while environmental exposures in transit, at work, school or other locations are largely ignored. Personal exposure monitors measure individuals' exposures over time; however, current personal monitors are intrusive and cannot be operated at a large scale over an extended period of time (e.g., for a continuous three months) and can be very costly. In addition, spatial locations typically cannot be identified when only personal monitors are used. In this paper, we piloted a study that applied momentary location tracking services supplied by smart phones to identify an individual's location in space-time for three consecutive months (April 28 to July 28, 2013) using available Wi-Fi networks. Individual exposures in space-time to the traffic-related pollutants Nitrogen Oxides (NOX) were estimated by superimposing an annual mean NOX concentration surface modeled using the Land Use Regression (LUR) modeling technique. Individual's exposures were assigned to stationary (including home, work and other stationary locations) and in-transit (including commute and other travel) locations. For the individual, whose home/work addresses were known and the commute route was fixed, it was found that 95.3% of the time, the individual could be accurately identified in space-time. The ambient concentration estimated at the home location was 21.01 ppb. When indoor/outdoor infiltration, indoor sources of air pollution and time spent outdoors were taken into consideration, the individual's cumulative exposures were 28.59 ppb and 96.49 ppb, assuming a respective indoor/outdoor ratio of 1.33 and 5.00. Integrating momentary location tracking services with fixed-site field monitoring, plus indoor-outdoor air exchange calibration, makes exposure assessment of a very large population over an extended time period

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

    SciTech Connect

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

    2008-11-15

    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 population exposure for landslide risk analysis using dasymetric cartography

    NASA Astrophysics Data System (ADS)

    Garcia, Ricardo A. C.; Oliveira, Sergio C.; Zezere, Jose L.

    2015-04-01

    Exposed Population is a major topic that needs to be taken into account in a full landslide risk analysis. Usually, risk analysis is based on an accounting of inhabitants number or inhabitants density, applied over statistical or administrative terrain units, such as NUTS or parishes. However, this kind of approach may skew the obtained results underestimating the importance of population, mainly in territorial units with predominance of rural occupation. Furthermore, the landslide susceptibility scores calculated for each terrain unit are frequently more detailed and accurate than the location of the exposed population inside each territorial unit based on Census data. These drawbacks are not the ideal setting when landslide risk analysis is performed for urban management and emergency planning. Dasymetric cartography, which uses a parameter or set of parameters to restrict the spatial distribution of a particular phenomenon, is a methodology that may help to enhance the resolution of Census data and therefore to give a more realistic representation of the population distribution. Therefore, this work aims to map and to compare the population distribution based on a traditional approach (population per administrative terrain units) and based on dasymetric cartography (population by building). The study is developed in the Region North of Lisbon using 2011 population data and following three main steps: i) the landslide susceptibility assessment based on statistical models independently validated; ii) the evaluation of population distribution (absolute and density) for different administrative territorial units (Parishes and BGRI - the basic statistical unit in the Portuguese Census); and iii) the dasymetric population's cartography based on building areal weighting. Preliminary results show that in sparsely populated administrative units, population density differs more than two times depending on the application of the traditional approach or the dasymetric

  15. Interpretation of benzene biomarkers of exposure for risk assessment

    EPA Science Inventory

    Human biomarkers of exposure such as parent or metabolite concentrations in blood or urine are often reported without any context to the sources of exposure or the implications for human risk. The Biomonitoring Technical Committee of the International Life Sciences Institute/Huma...

  16. Assessment of exposures to fecally-contaminated recreational water

    EPA Science Inventory

    Exposure to fecally-contaminated recreational waters can pose a health risk to swimmers and other recreators. Since 2003, we have interviewed nearly 27,000 respondents at seven beaches impacted by treated sewage discharge. Information was collected about the duration and exposure...

  17. Developing and Evaluating New Methods for Assessing Concurrent Environmental Exposures

    EPA Science Inventory

    Summary of purpose and scope (no longer than 200 words): One limitation to current environmental health research is the focus on single contaminant exposures. Each exposure estimated in epidemiologic models accounts for a relatively small proportion of observed variance in health...

  18. DATA REQUIREMENTS FOR ASSESSING CHILDREN'S EXPOSURE TO PESTICIDES

    EPA Science Inventory

    Several multimedia, multipathway exposure monitoring studies are currently being planned within EPA/NERL. The overall objectives of these studies are (1) to develop the data and models that can be used to estimate exposure and dose for young children to pesticides and (2) to i...

  19. Advancing Exposure Characterization for Chemical Evaluation and Risk Assessment

    EPA Science Inventory

    A new generation of scientific tools has emerged to rapidly measure signals from cells, tissues, and organisms following exposure to chemicals. High-visibility efforts to apply these tools for efficient toxicity testing raise important research questions in exposure science. As v...

  20. Polyfluoroalkyl Chemicals and Learning and Developmental Disorders: Epidemiology and Exposure Assessment

    ERIC Educational Resources Information Center

    Hoffman, Jennifer Kate

    2010-01-01

    This dissertation has two areas of focus: learning and developmental disorders (LDDs) and polyfluoroalkyl chemicals (PFCs). Epidemiological and exposure assessment methods are applied to each. The first paper used geographic location as a surrogate for exposure and broadly assesses the effect of the environment, both physical and social, on LDD…

  1. EMF exposure assessment in the Finnish garment industry: evaluation of proposed EMF exposure metrics.

    PubMed

    Hansen, N H; Sobel, E; Davanipour, Z; Gillette, L M; Niiranen, J; Wilson, B W

    2000-01-01

    Recently published studies indicate that having worked in occupations that involve moderate to high electromagnetic field (EMF) exposure is a risk factor for neurodegenerative diseases, including Alzheimer's disease. In these studies, the occupational groups most over-represented for EMF exposure comprised seamstresses, dressmakers, and tailors. Future epidemiologic studies designed to evaluate the possibility of a causal relationship between exposure to EMF and a neuro degenerative disease endpoint such as incidence of Alzheimer's disease, will benefit from the measurement of electromagnetic field metrics with potential biological relevance. Data collection methodology in such studies would be highly dependent upon how the metrics are defined. In this research the authors developed and demonstrated (1) protocols for collecting EMF exposure data suitable for estimating a variety of exposure metrics that may have biological relevance, and (2) analytical methods for calculation of these metrics. The authors show how exposure might be estimated under each of the three prominent EMF health-effects mechanism theories and evaluate the assertion that relative exposure ranking is dependent on which mechanism is assumed. The authors also performed AC RMS magnetic flux density measurements, confirming previously reported findings. The results indicate that seamstresses, as an occupational group, should be considered for study of the possible health effects of long-term EMF exposure.

  2. Fabrication of vertical nanowire resonators for aerosol exposure assessment

    NASA Astrophysics Data System (ADS)

    Merzsch, Stephan; Wasisto, Hutomo Suryo; Stranz, Andrej; Hinze, Peter; Weimann, Thomas; Peiner, Erwin; Waag, Andreas

    2013-05-01

    Vertical silicon nanowire (SiNW) resonators are designed and fabricated in order to assess exposure to aerosol nanoparticles (NPs). To realize SiNW arrays, nanolithography and inductively coupled plasma (ICP) deep reactive ion etching (DRIE) at cryogenic temperature are utilized in a top-down fabrication of SiNW arrays which have high aspect ratios (i.e., up to 34). For nanolithography process, a resist film thickness of 350 nm is applied in a vacuum contact mode to serve as a mask. A pattern including various diameters and distances for creating pillars is used (i.e., 400 nm up to 5 μm). In dry etching process, the etch rate is set high of 1.5 μm/min to avoid underetching. The etch profiles of Si wires can be controlled aiming to have either perpendicularly, negatively or positively profiled sidewalls by adjusting the etching parameters (e.g., temperature and oxygen content). Moreover, to further miniaturize the wire, multiple sacrificial thermal oxidations and subsequent oxide stripping are used yielding SiNW arrays of 650 nm in diameter and 40 μm in length. In the resonant frequency test, a piezoelectric shear actuator is integrated with the SiNWs inside a scanning electron microscope (SEM) chamber. The observation of the SiNW deflections are performed and viewed from the topside of the SiNWs to reduce the measurement redundancy. Having a high deflection of ~10 μm during its resonant frequency of 452 kHz and a low mass of 31 pg, the proposed SiNW is potential for assisting the development of a portable aerosol resonant sensor.

  3. The application of intraoperative transit time flow measurement to accurately assess anastomotic quality in sequential vein grafting

    PubMed Central

    Yu, Yang; Zhang, Fan; Gao, Ming-Xin; Li, Hai-Tao; Li, Jing-Xing; Song, Wei; Huang, Xin-Sheng; Gu, Cheng-Xiong

    2013-01-01

    OBJECTIVES Intraoperative transit time flow measurement (TTFM) is widely used to assess anastomotic quality in coronary artery bypass grafting (CABG). However, in sequential vein grafting, the flow characteristics collected by the conventional TTFM method are usually associated with total graft flow and might not accurately indicate the quality of every distal anastomosis in a sequential graft. The purpose of our study was to examine a new TTFM method that could assess the quality of each distal anastomosis in a sequential graft more reliably than the conventional TTFM approach. METHODS Two TTFM methods were tested in 84 patients who underwent sequential saphenous off-pump CABG in Beijing An Zhen Hospital between April and August 2012. In the conventional TTFM method, normal blood flow in the sequential graft was maintained during the measurement, and the flow probe was placed a few centimetres above the anastomosis to be evaluated. In the new method, blood flow in the sequential graft was temporarily reduced during the measurement by placing an atraumatic bulldog clamp at the graft a few centimetres distal to the anastomosis to be evaluated, while the position of the flow probe remained the same as in the conventional method. This new TTFM method was named the flow reduction TTFM. Graft flow parameters measured by both methods were compared. RESULTS Compared with the conventional TTFM, the flow reduction TTFM resulted in significantly lower mean graft blood flow (P < 0.05); in contrast, yielded significantly higher pulsatility index (P < 0.05). Diastolic filling was not significantly different between the two methods and was >50% in both cases. Interestingly, the flow reduction TTFM identified two defective middle distal anastomoses that the conventional TTFM failed to detect. Graft flows near the defective distal anastomoses were improved substantially after revision. CONCLUSIONS In this study, we found that temporary reduction of graft flow during TTFM seemed to

  4. Design strategy for assessing multi-pathway exposure for children: the Minnesota Children's Pesticide Exposure Study (MNCPES).

    PubMed

    Quackenboss, J J; Pellizzari, E D; Shubat, P; Whitmore, R W; Adgate, J L; Thomas, K W; Freeman, N C; Stroebel, C; Lioy, P J; Clayton, A C; Sexton, K

    2000-01-01

    Although children are exposed to a variety of environmental hazards, including pesticides, there is a scarcity of information available to estimate exposures realistically. This article reports on one of the first attempts to measure multi-pathway pesticide exposures in a population-based sample of urban and non-urban children. A design strategy was developed to assess multi-pathway pesticide exposures in children using personal exposure measurements in combination with complimentary measurements of biological markers of exposure, concentrations in relevant environmental media, and time spent in important microenvironments and participating in exposure-related activities. Sample collection and analysis emphasized measurement of three insecticides (i.e., chlorpyrifos, diazinon, and malathion) and one herbicide (i.e., atrazine). These compounds were selected because of their frequent use, presence in multiple environmental media, expected population exposures, and related hazard/toxicity. The study was conducted during the summer of 1997 in Minnesota and involved a stratified sample of households with children ages 3-12 years. Participants resided in either (a) the cities of Minneapolis and St. Paul (urban households), or (b) Rice and Goodhue Counties just south of the metropolitan area (non-urban households). Results from a residential inventory documenting storage and use of products containing the target pesticides were used to preferentially select households where children were likely to have higher exposures. The study successfully obtained pesticide exposure data for 102 children, including measurements of personal exposures (air, hand rinse, duplicate diet), environmental concentrations (residential indoor/outdoor air, drinking water, residential surfaces, soil), activity patterns (obtained by questionnaire, diary, videotaping), and internal dose (metabolites in urine).

  5. PET optimization for improved assessment and accurate quantification of {sup 90}Y-microsphere biodistribution after radioembolization

    SciTech Connect

    Martí-Climent, Josep M. Prieto, Elena; Elosúa, César; Rodríguez-Fraile, Macarena; Domínguez-Prado, Inés; Vigil, Carmen; García-Velloso, María J.; Arbizu, Javier; Peñuelas, Iván; Richter, José A.

    2014-09-15

    Purpose: {sup 90}Y-microspheres are widely used for the radioembolization of metastatic liver cancer or hepatocellular carcinoma and there is a growing interest for imaging {sup 90}Y-microspheres with PET. The aim of this study is to evaluate the performance of a current generation PET/CT scanner for {sup 90}Y imaging and to optimize the PET protocol to improve the assessment and the quantification of {sup 90}Y-microsphere biodistribution after radioembolization. Methods: Data were acquired on a Biograph mCT-TrueV scanner with time of flight (TOF) and point spread function (PSF) modeling. Spatial resolution was measured with a{sup 90}Y point source. Sensitivity was evaluated using the NEMA 70 cm line source filled with {sup 90}Y. To evaluate the count rate performance, {sup 90}Y vials with activity ranging from 3.64 to 0.035 GBq were measured in the center of the field of view (CFOV). The energy spectrum was evaluated. Image quality with different reconstructions was studied using the Jaszczak phantom containing six hollow spheres (diameters: 31.3, 28.1, 21.8, 16.1, 13.3, and 10.5 mm), filled with a 207 kBq/ml {sup 90}Y concentration and a 5:1 sphere-to-background ratio. Acquisition time was adjusted to simulate the quality of a realistic clinical PET acquisition of a patient treated with SIR-Spheres{sup ®}. The developed methodology was applied to ten patients after SIR-Spheres{sup ®} treatment acquiring a 10 min per bed PET. Results: The energy spectrum showed the{sup 90}Y bremsstrahlung radiation. The {sup 90}Y transverse resolution, with filtered backprojection reconstruction, was 4.5 mm in the CFOV and degraded to 5.0 mm at 10 cm off-axis. {sup 90}Y absolute sensitivity was 0.40 kcps/MBq in the center of the field of view. Tendency of true and random rates as a function of the {sup 90}Y activity could be accurately described using linear and quadratic models, respectively. Phantom studies demonstrated that, due to low count statistics in {sup 90}Y PET

  6. Modelling personal exposure to particulate air pollution: an assessment of time-integrated activity modelling, Monte Carlo simulation & artificial neural network approaches.

    PubMed

    McCreddin, A; Alam, M S; McNabola, A

    2015-01-01

    An experimental assessment of personal exposure to PM10 in 59 office workers was carried out in Dublin, Ireland. 255 samples of 24-h personal exposure were collected in real time over a 28 month period. A series of modelling techniques were subsequently assessed for their ability to predict 24-h personal exposure to PM10. Artificial neural network modelling, Monte Carlo simulation and time-activity based models were developed and compared. The results of the investigation showed that using the Monte Carlo technique to randomly select concentrations from statistical distributions of exposure concentrations in typical microenvironments encountered by office workers produced the most accurate results, based on 3 statistical measures of model performance. The Monte Carlo simulation technique was also shown to have the greatest potential utility over the other techniques, in terms of predicting personal exposure without the need for further monitoring data. Over the 28 month period only a very weak correlation was found between background air quality and personal exposure measurements, highlighting the need for accurate models of personal exposure in epidemiological studies.

  7. Sulfuric acid aerosol exposure in humans assessed by bronchoalveolar lavage

    SciTech Connect

    Frampton, M.W.; Voter, K.Z.; Morrow, P.E.; Roberts, N.J. Jr.; Culp, D.J.; Cox, C.; Utell, M.J. )

    1992-09-01

    Epidemiologic and experimental evidence suggests that exposure to acidic aerosols may affect human health. Brief exposures to acidic aerosols alter mucociliary clearance and increase airway responsiveness, but effects on host defense mechanisms at the alveolar level have not been studied in humans. Twelve healthy, nonsmoking volunteers between 20 and 39 yr of age were exposed for 2 h to aerosols of approximately 1,000 micrograms/m3 sulfuric acid (H2SO4) or sodium chloride (NaCl (control)), with intermittent exercise, in a randomized, double-blind fashion. Each subject received both exposures, separated by at least 2 wk. Bronchoalveolar lavage (BAL) was performed 18 h after exposure in order to detect evidence of an inflammatory response, changes in alveolar cell subpopulations, or changes in alveolar macrophage (AM) function, which is important in host defense. When compared with NaCl, exposure to H2SO4 did not increase polymorphonuclear leukocytes in BAL fluid. The percentage of T lymphocytes decreased in association with H2SO4 exposure, but the difference was not statistically significant (14.9% after NaCl, 11.5% after H2SO4; p = 0.14). Antibody-mediated cytotoxicity of AM increased in association with H2SO4 exposure (percent lysis 19.1 after NaCl, 23.6 after H2SO4; p = 0.16). No significant change was seen in release of superoxide anion or inactivation of influenza virus in vitro. Brief exposures to H2SO4 aerosol at 1,000 micrograms/m3 do not cause an influx of inflammatory cells into the alveolar space, and no evidence was found for alteration in antimicrobial defense 18 h after exposure.

  8. Use of CALPUFF for exposure assessment in a near-field, complex terrain setting

    NASA Astrophysics Data System (ADS)

    MacIntosh, David L.; Stewart, James H.; Myatt, Theodore A.; Sabato, Joseph E.; Flowers, George C.; Brown, Kirk W.; Hlinka, Dennis J.; Sullivan, David A.

    2010-01-01

    CALPUFF is an atmospheric source-receptor model recommended by the U.S. Environmental Protection Agency for use on a case-by-case basis in complex terrain and wind conditions. The ability of the model to provide useful information for exposure assessments in areas with those topographical and meteorological conditions has received little attention. This is an important knowledge gap for use of CALPUFF outside of regulatory applications, such as exposure analyses conducted in support of risk assessments and health studies. We compared deposition of cadmium (Cd), lead (Pb), and zinc (Zn) calculated with CALPUFF as a result of emissions from a zinc smelter with corresponding concentrations of the metals measured in attic dust and soil samples obtained from the surrounding area. On a point-by-point analysis, predictions from CALPUFF explained 11% (lead) to 53% (zinc) of the variability in concentrations measured in attic dust. Levels of heavy metals in soil interpolated to 100 residential addresses from the distribution of concentrations measured in soil samples also agreed well with deposition predicted with CALPUFF: R2 of 0.46, 0.76, and 079 for Pb, Cd, and Zn, respectively. Community-average concentrations of Cd, Pb, and Zn measured in soil were significantly ( p < 0.0001) and strongly correlated ( R2 ranged from 0.77 to 0.98) with predicted deposition rates. These findings demonstrate that CALPUFF can provide reasonably accurate predictions of the patterns of long-term air pollutant deposition in the near-field associated with emissions from a discrete source in complex terrain. Because deposition estimates are calculated as a linear function of air concentrations, CALPUFF is expected to be reliable model for prediction of long-term average, near-field ambient air concentrations in complex terrain as well.

  9. Can Community Health Workers Report Accurately on Births and Deaths? Results of Field Assessments in Ethiopia, Malawi and Mali

    PubMed Central

    Silva, Romesh; Amouzou, Agbessi; Munos, Melinda; Marsh, Andrew; Hazel, Elizabeth; Victora, Cesar; Black, Robert; Bryce, Jennifer

    2016-01-01

    Introduction Most low-income countries lack complete and accurate vital registration systems. As a result, measures of under-five mortality rates rely mostly on household surveys. In collaboration with partners in Ethiopia, Ghana, Malawi, and Mali, we assessed the completeness and accuracy of reporting of births and deaths by community-based health workers, and the accuracy of annualized under-five mortality rate estimates derived from these data. Here we report on results from Ethiopia, Malawi and Mali. Method In all three countries, community health workers (CHWs) were trained, equipped and supported to report pregnancies, births and deaths within defined geographic areas over a period of at least fifteen months. In-country institutions collected these data every month. At each study site, we administered a full birth history (FBH) or full pregnancy history (FPH), to women of reproductive age via a census of households in Mali and via household surveys in Ethiopia and Malawi. Using these FBHs/FPHs as a validation data source, we assessed the completeness of the counts of births and deaths and the accuracy of under-five, infant, and neonatal mortality rates from the community-based method against the retrospective FBH/FPH for rolling twelve-month periods. For each method we calculated total cost, average annual cost per 1,000 population, and average cost per vital event reported. Results On average, CHWs submitted monthly vital event reports for over 95 percent of catchment areas in Ethiopia and Malawi, and for 100 percent of catchment areas in Mali. The completeness of vital events reporting by CHWs varied: we estimated that 30%-90% of annualized expected births (i.e. the number of births estimated using a FPH) were documented by CHWs and 22%-91% of annualized expected under-five deaths were documented by CHWs. Resulting annualized under-five mortality rates based on the CHW vital events reporting were, on average, under-estimated by 28% in Ethiopia, 32% in

  10. Probabilistic assessment of exposure to cosmetic products by French children aged 0-3 years.

    PubMed

    Ficheux, A S; Dornic, N; Bernard, A; Chevillotte, G; Roudot, A C

    2016-08-01

    Very few exposure data are available for children in Europe and worldwide. The aim of this study was to assess the exposure to cosmetic products used on children aged 0-3 years using recent consumption data generated for the French population. Exposure was assessed using a probabilistic method for 24 products including cleanser, skin care, fragrance, solar and bottom products. The exposure data obtained in this study for children aged 0-3 years were higher than the values fixed by the SCCS for all common products: liquid shampoo, face moisturizer cream, toothpaste, shower gel and body moisturizer cream. Exposure was assessed for the first time for many products such as sunscreens, Eau de toilette and massage products. These new French exposure values will be useful for safety assessors and for safety agencies. PMID:27255804

  11. Exposure assessment and risk characterization for perfluorooctanoate in selected consumer articles.

    PubMed

    Washburn, Stephen T; Bingman, Timothy S; Braithwaite, Scott K; Buck, Robert C; Buxton, L William; Clewell, Harvey J; Haroun, Lynne A; Kester, Janet E; Rickard, Robert W; Shipp, Annette M

    2005-06-01

    An exposure assessment and risk characterization was conducted to better understand the potential human health significance of trace levels of perfluorooctanoate (PFO) detected in certain consumer articles. PFO is the anion of perfluorooctanoic acid (PFOA). Concentrations of PFO in the consumer articles were determined from extraction tests and product formulation information. Potential exposures during consumer use of the articles were quantified based on an assessment of behavior patterns and regulatory guidance. Health benchmarks were developed and then compared to the exposure estimates to yield margins of exposure (MOEs). A simple one-compartment model was also developed to estimate contributions of potential consumer exposures to PFO concentrations in serum. While there are considerable uncertainties in this assessment, it indicates that exposures to PFO during consumer use of the articles evaluated in this study are not expected to cause adverse human health effects in infants, children, adolescents, adult residents, or professionals nor result in quantifiable levels of PFO in human serum.

  12. Assessment of RT-qPCR normalization strategies for accurate quantification of extracellular microRNAs in murine serum.

    PubMed

    Roberts, Thomas C; Coenen-Stass, Anna M L; Wood, Matthew J A

    2014-01-01

    Extracellular microRNAs (miRNAs) are under investigation as minimally-invasive biomarkers for a wide range of disease conditions. We have recently shown in a mouse model of the progressive muscle-wasting condition Duchenne muscular dystrophy (DMD) that a set of highly elevated serum miRNAs reflects the regenerative status of muscle. These miRNAs are promising biomarkers for monitoring DMD disease progression and the response to experimental therapies. The gold standard miRNA detection methodology is Reverse Transcriptase-quantitative Polymerase Chain Reaction (RT-qPCR), which typically exhibits high sensitivity and wide dynamic range. Accurate determination of miRNA levels is affected by RT-qPCR normalization method and therefore selection of the optimal strategy is of critical importance. Serum miRNA abundance was measured by RT-qPCR array in 14 week old mice, and by individual RT-qPCR assays in a time course experiment spanning 48 weeks. Here we utilize these two datasets to assess the validity of three miRNA normalization strategies (a) normalization to the average of all Cq values from array experiments, (b) normalization to a stably expressed endogenous reference miRNA, and (c) normalization to an external spike-in synthetic oligonucleotide. Normalization approaches based on endogenous control miRNAs result in an under-estimation of miRNA levels by a factor of ∼2. An increase in total RNA and total miRNA was observed in dystrophic serum which may account for this systematic bias. We conclude that the optimal strategy for this model system is to normalize to a synthetic spike-in control oligonucleotide.

  13. LESSONS LEARNED FROM THE NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY (NHEXAS)

    EPA Science Inventory

    Three NHEXAS Studies were conducted from 1995-1997 to evaluate total human exposure to multiple chemicals on community and regional scales. EPA established cooperative agreements with three Consortia to conduct three interrelated NHEXAS field studies. The University of Arizona...

  14. Exposure assessment to glyphosate of two species of annelids.

    PubMed

    García-Torres, Tristán; Giuffré, Lidia; Romaniuk, Romina; Ríos, Ruth P; Pagano, Eduardo A

    2014-08-01

    Adult mortality, biomass, fecundity and viability of cocoons were studied in Eisenia fetida and Octolasion tyrtaeum, in response to glyphosate exposure in soil. Exposure tests were carried out following USEPA procedure, with five concentrations of glyphosate in soil and a control. O. tyrtaeum was more sensitive to the highest concentration of glyphosate (50,000 mg kg(-1)), with 100 % mortality by day 7 of exposure, compared with 71 % for E. fetida. Although biomass of O. tyrtaeum was significantly different between the control and 5,000 mg kg(-1) dose at day 14, E. fetida was not affected at that concentration, and only showed a significant weight loss after 7 days of exposure to 50,000 mg kg(-1). Adverse effects upon adult fecundity and cocoon viability were observed at glyphosate concentrations of 5,000 mg kg(-1) and above. Adverse effects were observed at concentrations that greatly exceeded the recommended field application rates of glyphosate.

  15. USING BIOMONITORING DATA TO INFORM EXPOSURE ASSESSMENT IN CHILDREN

    EPA Science Inventory

    Discussing the challenges associated with estimating and interpreting toxicant exposures and health risks from biomonitoring data. Extended abstract will also be translated in Spanish and published in Acta Toxicologica Argentina.

  16. ENVIRONMENTAL MONITORING AND HUMAN EXPOSURE ASSESSMENT USING IMMUNOCHEMICAL TECHNIQUES

    EPA Science Inventory

    The use of immunochemical technologies including, but not limited to, immunoassays is expanding to include various aspects of environmental analysis. Ultimately, the basis for environmental investigations is concern about human and ecological exposure to potentially toxic compoun...

  17. The practice of exposure assessment: a state-of-the-art review.

    PubMed

    Paustenbach, D J

    2000-01-01

    Each of us encounters hundreds of toxic agents everyday, without exposure and subsequent absorption (uptake) however, there is no risk of injury. Thus, exposure assessment is one of the three legs of the stool (along with toxicity assessment and dose-response assessment) upon which the practice of risk assessment rests. The field of exposure assessment has evolved out of at least 3 other disciplines over the past 50 years, including health physics, industrial hygiene, and epidemiology. Exposure assessments are a necessary component to understanding the hazard posed by exposure to naturally (e.g., aflatoxins in foods, radon in air) and nonnaturally occurring toxicants (e.g., benzene in groundwater, MTBE in air, and food additives). This article presents a thorough review of the field, including a discussion of the terminology used in exposure assessment, a description of how to quantitatively estimate dose for the major sources of exposure (food, water, air, and soil), and many of the best sources of information. In addition, techniques for assessing both variability and uncertainty are presented. Lessons learned over the past twenty years are emphasized. Some example calculations are included, nearly 400 references are cited, and a glossary of terms is provided.

  18. Reliable exposure assessment strategies for physical ergonomics stressors in construction and other non-routinized work.

    PubMed

    Paquet, Victor; Punnett, Laura; Woskie, Susan; Buchholz, Bryan

    2005-07-15

    The objective of this research was to provide guidelines for the reliable assessment of ergonomics exposures in non-routinized work. Using a discrete-interval observational sampling approach, two or three observers collected a total of 5852 observations on tasks performed by three construction trades (iron workers, carpenters and labourers) for periods of several weeks. For each observation, nine exposure variables associated with awkward body postures, tool use and load handling were recorded. The frequency of exposure to each variable was calculated for each worker during each of the tasks on each of the days. ANOVA was used to assess the importance of task in explaining between-worker and within-worker variability in exposures across days. A statistical re-sampling method (bootstrap) was used to evaluate the reliability of exposure estimates for groups of workers performing the same task for different sampling periods. Most exposures were found to vary significantly across construction tasks within trade, and between-worker exposure variability was generally smaller than within-worker exposure variability within task. Bootstrapping showed that the reliability of the group estimates exposure for the most variable exposures within task tended to improve as the assessment periods approached 5-6 d, with marginal improvements for longer assessment periods. Reliable group estimates of exposure for the least variable exposures within task were obtained with 1 or 2 d of observation. The results of this study demonstrate that an initial estimate of the important environmental or task sources of exposure variability can be used to develop an efficient sampling strategy that provides reliable estimates of ergonomics exposures during non-routinized work.

  19. Computational exposure assessment of electromagnetic fields generated by an RFID system for mother--newborn identity reconfirmation.

    PubMed

    Fiocchi, Serena; Parazzini, Marta; Paglialonga, Alessia; Ravazzani, Paolo

    2011-07-01

    Radio frequency identification (RFID) is an innovative technology currently applied in a large number of industrial and consumer applications. The spread of RFID technology does not correspond to a parallel increase in studies on its possible impact on health in terms of electromagnetic field (EMF) exposure. The aim of this paper is to estimate, by computational techniques, the EMF generated by passive RFID systems for mother-newborn identity reconfirmation. The computation was performed on realistic models of newborn and mother for three different reader positions. The compliance with EMF exposure guidelines was investigated as a function of the change in reader-tag specifications (magnetic field threshold and maximum distance of the reader to awake the tag) and time of use of the reader close to the body. The results show that attention should be paid to the identification of the optimal reader-tag technical specifications to be used in this type of application. That should be done by an accurate exposure assessment investigation, in particular for newborn exposure. The need to reduce the exposure time as much as possible indicates the importance of specific training on the practical applications of the RFID (DATALOGIC J-series, Bologna, Italy) device.

  20. Multimedia Environmental Pollutant Assessment System (MEPAS{reg_sign}): Exposure pathway and human health impact assessment models

    SciTech Connect

    Strenge, D.L.; Chamberlain, P.J.

    1995-05-01

    The Multimedia Environmental Pollutant Assessment System (MEPAS) provides physics-based models for human health risk assessment for radioactive and hazardous pollutants. MEPAS analyzes pollutant behavior in various media (air, soil, groundwater and surface water) and estimates transport through and between media and exposure and impacts to the environment, to the maximum individual, and to populations. MEPAS includes 25 exposure pathway models, a database with information on more than 650 contaminants, and a sensitivity module that allows for uncertainty analysis. Four major transport pathways are considered in MEPAS: groundwater, overland, surface water, and atmospheric. This report describes the exposure pathway and health impact assessment component of MEPAS, which provides an estimate of health impacts to selected individuals and populations from exposure to pollutants. The exposure pathway analysis starts with pollutant concentration in a transport medium and estimates the average daily dose to exposed individuals from contact with the transport medium or a secondary medium contaminated by the transport medium. The average daily dose is then used to estimate a measure of health impact appropriate to the type of pollutant considered. Discussions of the exposure pathway models include the assumptions and equations used to convert the transport medium concentrations to exposure medium concentrations. The discussion for a given exposure pathway defines the transport pathways leading to the exposure, the special processes considered in determining the pollutant concentration in the exposure medium, and the exposure model used to estimate the average daily dose. Models for the exposure pathway and health impact assessments require definition of several parameters. A summary of the notation used for these parameters is provided.

  1. Health risk assessment of personal inhalation exposure to volatile organic compounds in Tianjin, China.

    PubMed

    Zhou, Jian; You, Yan; Bai, Zhipeng; Hu, Yandi; Zhang, Jiefeng; Zhang, Nan

    2011-01-01

    Volatile Organic Compounds (VOCs) exposure can induce a range of adverse human health effects. To date, however, personal VOCs exposure and residential indoor and outdoor VOCs levels have not been well characterized in the mainland of China, less is known about health risk of personal exposure to VOCs. In this study, personal exposures for 12 participants as well as residential indoor/outdoor, workplace and in vehicle VOCs concentrations were measured simultaneously in Tianjin, China. All VOCs samples were collected using passive samplers for 5 days and were analyzed using Thermal Desorption GC-MS method. U.S. Environmental Protect Agency's Inhalation Unit Risks were used to calculate the inhalation cancer health risk. To assess uncertainty of health risk estimate, Monte Carlo simulation and sensitivity analysis were implemented. Personal exposures were greater than residential indoor exposures as expected with the exception of carbon tetrachloride. Exposure assessment showed modeled and measured concentrations are statistically linearly correlated for all VOCs (P<0.01) except chloroform, confirming that estimated personal exposure using time-weighted model can provide reasonable estimate of personal inhalation exposure to VOCs. Indoor smoking and recent renovation were identified as two major factors influencing personal exposure based on the time-activity pattern and factor analysis. According to the cancer risk analysis of personal exposure, benzene, chloroform, carbon tetrachloride and 1,3-butadiene had median upper-bound lifetime cancer risks that exceeded the U.S. EPA benchmark of 1 per one million, and benzene presented the highest median risks at about 22 per one million population. The median cumulative cancer risk of personal exposure to 5 VOCs was approximately 44 per million, followed by indoor exposure (37 per million) and in vehicle exposure (36 per million). Sensitivity analysis suggested that improving the accuracy of exposure measurement in further

  2. Windsor, Ontario Exposure Assessment Study: Design and Methods Validation of Personal, Indoor and Outdoor Air Pollution Monitoring

    EPA Science Inventory

    The Windsor, Ontario Exposure Assessment Study evaluated the contribution of ambient air pollutants to personal and indoor exposures of adults and asthmatic children living in Windsor, Ontario, Canada. In addition, the role of personal, indoor, and outdoor air pollution exposures...

  3. Assessment of airborne exposure and dermal contact to acrylamide during chemical grouting operations. Final report

    SciTech Connect

    McHugh, J.M.

    1987-07-22

    Acrylamide exposure may occur by inhalation, ingestion and skin absorption; acrylamide is a neurotoxin and an irritant. The report details the results of field studies to assess airborne exposure and dermal contact to acrylamide during chemical grouting operations. Occupational exposures to acrylamide were characterized for sewer mainline, lateral line, and manhole maintenance operations. The objective of the study was to collect exposure data based on observations and measurements to be used as an integral part of a quantitative risk assessment by the U.S. Environmental Protection Agency's Office of Toxic Substances.

  4. Exposure assessment at extremely low frequencies: Issues, instrumentation, modeling, and data

    NASA Astrophysics Data System (ADS)

    Sussman, Stanley S.

    1995-01-01

    Epidemiologic studies suggesting a possible link between exposure to ELF magnetic fields and increased cancer risk have spurred interest in the assessment of field levels and exposures in residences, the workplace, and other environments. Characteristics such as high degrees of spatial and temporal variability and the presence of multiple frequencies can complicate assessment strategies. Instrumentation development has proceeded rapidly, and a number of measurement systems of varying sophistication are now commercially available. For situations where measurement is not feasible or practical, computer modeling is expanding the scope of exposure estimation. Health-oriented studies and measurement surveys are adding to a growing database of field and exposure levels.

  5. Assessment of Prenatal Exposure to Arsenic in Tenerife Island

    PubMed Central

    Vall, Oriol; Gómez-Culebras, Mario; Garcia-Algar, Oscar; Joya, Xavier; Velez, Dinoraz; Rodríguez-Carrasco, Eva; Puig, Carme

    2012-01-01

    Introduction Increasing awareness of the potential chronic health effects of arsenic (As) at low exposure levels has motivated efforts to better understand impaired child development during pregnancy by biomarkers of exposure. The aims of this study were to evaluate the prenatal exposure to As by analysis of an alternative matrix (meconium), to examine its effects on neonatal outcomes and investigate the association with maternal lifestyle and dietary habits during pregnancy. Methods A transversal descriptive study was conducted in Tenerife (Spain). A total of 96 mother-child pairs participated in the study. A questionnaire on sociodemographic, lifestyle and dietary habits during pregnancy was administered the day after the delivery. Analysis of total As in meconium was performed by inductively coupled plasma-optical emission spectrometer. Results Total As was detected in 37 (38.5%) meconium samples. The univariate logistic regression model indicates that prenatal exposure to As was associated with a low intake of eggs per week (OR 0.56; CI (95%): 0.34–0.94) during pregnancy. Conversely, frequent intake of vegetables was associated with prenatal As exposure (OR: 1.19; CI (95%): 1.01–1.41) and frequent intake of processed meat (as bacon, Frankfurt’s sausage, and hamburger) shows a trend to As prenatal exposure (OR: 8.54; CI (95%): 0.80–90.89). The adjusted multivariate logistic regression model indicates that only frequent intake of vegetables maintains the association (OR: 1.31; CI (95%): 1.02–1.68). Conclusion The studied population presented a low As exposure and was not associated with neonatal effects. Maternal consumption of vegetables during pregnancy was associated with detectable meconium As levels; however the concentration detected in meconium was too low to be considered a major public health concern in this geographical area. PMID:23209747

  6. Assessing exposure in epidemiologic studies to disinfection by-products in drinking water: report from an international workshop.

    PubMed Central

    Arbuckle, Tye E; Hrudey, Steve E; Krasner, Stuart W; Nuckols, Jay R; Richardson, Susan D; Singer, Philip; Mendola, Pauline; Dodds, Linda; Weisel, Clifford; Ashley, David L; Froese, Kenneth L; Pegram, Rex A; Schultz, Irvin R; Reif, John; Bachand, Annette M; Benoit, Frank M; Lynberg, Michele; Poole, Charles; Waller, Kirsten

    2002-01-01

    The inability to accurately assess exposure has been one of the major shortcomings of epidemiologic studies of disinfection by-products (DBPs) in drinking water. A number of contributing factors include a) limited information on the identity, occurrence, toxicity, and pharmacokinetics of the many DBPs that can be formed from chlorine, chloramine, ozone, and chlorine dioxide disinfection; b) the complex chemical interrelationships between DBPs and other parameters within a municipal water distribution system; and c) difficulties obtaining accurate and reliable information on personal activity and water consumption patterns. In May 2000, an international workshop was held to bring together various disciplines to develop better approaches for measuring DBP exposure for epidemiologic studies. The workshop reached consensus about the clear need to involve relevant disciplines (e.g., chemists, engineers, toxicologists, biostatisticians and epidemiologists) as partners in developing epidemiologic studies of DBPs in drinking water. The workshop concluded that greater collaboration of epidemiologists with water utilities and regulators should be encouraged in order to make regulatory monitoring data more useful for epidemiologic studies. Similarly, exposure classification categories in epidemiologic studies should be chosen to make results useful for regulatory or policy decision making. PMID:11834463

  7. Quantitative Plasma Biomarker Analysis in HDI Exposure Assessment

    PubMed Central

    Flack, Sheila L.; Fent, Kenneth W.; Trelles Gaines, Linda G.; Thomasen, Jennifer M.; Whittaker, Steve; Ball, Louise M.; Nylander-French, Leena A.

    2010-01-01

    Quantification of amines in biological samples is important for evaluating occupational exposure to diisocyanates. In this study, we describe the quantification of 1,6-hexamethylene diamine (HDA) levels in hydrolyzed plasma of 46 spray painters applying 1,6-hexamethylene diisocyanate (HDI)-containing paint in vehicle repair shops collected during repeated visits to their workplace and their relationship with dermal and inhalation exposure to HDI monomer. HDA was detected in 76% of plasma samples, as heptafluorobutyryl derivatives, and the range of HDA concentrations was ≤0.02–0.92 μg l−1. After log-transformation of the data, the correlation between plasma HDA levels and HDI inhalation exposure measured on the same workday was low (N = 108, r = 0.22, P = 0.026) compared with the correlation between plasma HDA levels and inhalation exposure occurring ∼20 to 60 days before blood collection (N = 29, r = 0.57, P = 0.0014). The correlation between plasma HDA levels and HDI dermal exposure measured on the same workday, although statistically significant, was low (N = 108, r = 0.22, P = 0.040) while the correlation between HDA and dermal exposure occurring ∼20 to 60 days before blood collection was slightly improved (N = 29, r = 0.36, P = 0.053). We evaluated various workplace factors and controls (i.e. location, personal protective equipment use and paint booth type) as modifiers of plasma HDA levels. Workers using a downdraft-ventilated booth had significantly lower plasma HDA levels relative to semi-downdraft and crossdraft booth types (P = 0.0108); this trend was comparable to HDI inhalation and dermal exposure levels stratified by booth type. These findings indicate that HDA concentration in hydrolyzed plasma may be used as a biomarker of cumulative inhalation and dermal exposure to HDI and for investigating the effectiveness of exposure controls in the workplace. PMID:19805392

  8. National Human Exposure Assessment Survey: analysis of exposure pathways and routes for arsenic and lead in EPA Region 5.

    PubMed

    Clayton, C A; Pellizzari, E D; Quackenboss, J J

    2002-01-01

    The National Human Exposure Assessment Survey (NHEXAS) Phase I field study conducted in EPA Region 5 (Great Lakes Area) provides extensive exposure data on a representative sample of approximately 250 residents of the region. Associated environmental media and biomarker (blood, urine) concentration data were also obtained for the study participants to aid in understanding of the relationships of exposures to both contaminant pathways and doses. Besides fulfilling the primary NHEXAS objectives, the NHEXAS data provided an opportunity to explore secondary usages, such as examining pathway to route of exposure relationships. A generic type of structural equation model was used to define the anticipated relationships among the various data types for both arsenic (As) and lead (Pb). Since, by design, only a few participants provided data for all sample types, implementing this model required that some media concentrations (outdoor air and soil) be imputed for subjects with missing information by using measurements collected in the same geographic area and time period. The model, and associated pairwise correlations, generally revealed significant but weak associations among the concentrations, exposures, and doses; the strongest associations occurred for the various air measurements (indoor versus outdoor and personal). The generally weak associations were thought to be partly due to the absence of complete coverage of nonresidential environmental media and to nonsynchronization of relevant measurement times and integration periods of collection across the various sample types. In general, relationships between the NHEXAS questionnaire data and the various concentration, exposure, and body-burden measures were also weak. The model results and the modeling exercise suggest several ways for optimizing the design of future exposure assessment studies that are aimed at supporting structural modeling activities. PMID:11859431

  9. Hydrogeologic assessment of exposure to solvent-contaminated drinking water: Pregnancy outcomes in relation to exposure

    SciTech Connect

    Wrensch, M.; Swan, S.; Murphy, P.J.; Lipscomb, J.; Claxton, K.; Epstein, D.; Neutra, R. )

    1990-07-01

    We recently concluded that exposure to solvent-contaminated drinking water was an unlikely explanation for observed excesses of adverse pregnancy outcomes during 1980-1981 in the Los Paseos neighborhood of Santa Clara County, California, because these excesses were not observed in an adjacent exposed area. The validity of this conclusion depends on the assumption that the two areas had comparable exposure. Using quantitative methods to model movement of the solvent leak plume and water flow within the distribution system, we estimated that women with adverse outcomes were no more likely to have received contaminated water than women with normal live births. These results strengthen the conclusion that exposures to water from the contaminated well were not responsible for the excess of adverse outcomes observed in the Los Paseos area.

  10. Estimated exposure to phthalates in cosmetics and risk assessment.

    PubMed

    Koo, Hyun Jung; Lee, Byung Mu

    2004-12-01

    Some phthalates such as di(2-ethylhexyl) phthalate (DEHP) and dibutyl phthalate (DBP) and their metabolites are suspected of producing teratogenic or endocrine-disrupting effects. To predict possible human exposure to phthalates in cosmetics, the levels of DEHP, diethyl phthalate (DEP), DBP, and butylbenzyl phthalate (BBP) were determined by high-performance liquid chromatography (HPLC) in 102 branded hair sprays, perfumes, deodorants, and nail polishes. DBP was detected in 19 of the 21 nail polishes and in 11 of the 42 perfumes, and DEP was detected in 24 of the 42 perfumes and 2 of the 8 deodorants. Median exposure levels to phthalates in cosmetics by dermal absorption were estimated to be 0.0006 g/kg body weight (bw)/d for DEHP, 0.6 g/kg bw/d for DEP, and 0.103 g/kg bw/d for DBP. Furthermore, if phthalates in cosmetics were assumed to be absorbed exclusively via 100% inhalation, the median daily exposure levels to phthalates in cosmetics were estimated to be 0.026 g/kg bw/d for DEHP, 81.471 g/kg bw/d for DEP, and 22.917 g/kg bw/d for DBP, which are far lower than the regulation levels set buy the Scientific Committee on Toxicity, Ecotoxicity, and the Environment (CSTEE) (37 g/kg bw/d, DEHP), Agency for Toxic Substances and Disease Registry (ATSDR) (7000 g/kg bw/d, DEP), and International Programme on Chemical Safety (IPCS) (66 g/kg bw/d, DBP), respectively. Based on these data, hazard indices (HI, daily exposure level/regulation level) were calculated to be 0.0007 for DEHP, 0.012 for DEP, and 0.347 for DBP. These data suggest that estimated exposure to-phthalates in the cosmetics mentioned are relatively small. However, total exposure levels from several sources may be greater and require further investigation.

  11. Effects analysis of time-varying or repeated exposures in aquatic ecological risk assessment of agrochemicals.

    PubMed

    Reinert, Kevin H; Giddings, Jeffrey M; Judd, Laura

    2002-09-01

    Exposure to agrochemicals in the aquatic environment often occurs as time-varying or repeated pulses. Time-varying exposures may occur due to runoff events and spray drift associated with precipitation and application events. Hydrologic dilution, dispersion, and degradation also produce pulsed exposures. Standard laboratory toxicity tests using constant exposure concentrations typically do not investigate the toxicity of time-varying or repeated exposures. Detoxification, elimination, and recovery may occur within organisms or populations during the periods between exposures. The difficulty of estimating effects of realistic time-varying exposures from measurements made under constant exposure conditions is often an important source of uncertainty in ecological risk assessment of pesticides. This article discusses the criteria and tools for deciding whether time-varying exposures are relevant in a particular risk assessment, approaches for laboratory toxicity testing with time-varying exposure, modeling approaches for addressing effects oftime-varying exposure, deterministic and probabilistic ecological risk characterization of time-varyingexposures and toxicity, and uncertainty analysis.

  12. Personal exposure assessment to particulate metals using a paper-based analytical device

    NASA Astrophysics Data System (ADS)

    Cate, David; Volckens, John; Henry, Charles

    2013-03-01

    The development of a paper-based analytical device (PAD) for assessing personal exposure to particulate metals will be presented. Human exposure to metal aerosols, such as those that occur in the mining, construction, and manufacturing industries, has a significant impact on the health of our workforce, costing an estimated $10B in the U.S and causing approximately 425,000 premature deaths world-wide each year. Occupational exposure to particulate metals affects millions of individuals in manufacturing, construction (welding, cutting, blasting), and transportation (combustion, utility maintenance, and repair services) industries. Despite these effects, individual workers are rarely assessed for their exposure to particulate metals, due mainly to the high cost and effort associated with personal exposure measurement. Current exposure assessment methods for particulate metals call for an 8-hour filter sample, after which time, the filter sample is transported to a laboratory and analyzed by inductively-coupled plasma (ICP). The time from sample collection to reporting is typically weeks and costs several hundred dollars per sample. To exacerbate the issue, method detection limits suffer because of sample dilution during digestion. The lack of sensitivity hampers task-based exposure assessment, for which sampling times may be tens of minutes. To address these problems, and as a first step towards using microfluidics for personal exposure assessment, we have developed PADs for measurement of Pb, Cd, Cr, Fe, Ni, and Cu in aerosolized particulate matter.

  13. A pragmatic approach to assess the exposure of the honey bee (Apis mellifera) when subjected to pesticide spray.

    PubMed

    Poquet, Yannick; Bodin, Laurent; Tchamitchian, Marc; Fusellier, Marion; Giroud, Barbara; Lafay, Florent; Buleté, Audrey; Tchamitchian, Sylvie; Cousin, Marianne; Pélissier, Michel; Brunet, Jean-Luc; Belzunces, Luc P

    2014-01-01

    Plant protection spray treatments may expose non-target organisms to pesticides. In the pesticide registration procedure, the honey bee represents one of the non-target model species for which the risk posed by pesticides must be assessed on the basis of the hazard quotient (HQ). The HQ is defined as the ratio between environmental exposure and toxicity. For the honey bee, the HQ calculation is not consistent because it corresponds to the ratio between the pesticide field rate (in mass of pesticide/ha) and LD50 (in mass of pesticide/bee). Thus, in contrast to all other species, the HQ can only be interpreted empirically because it corresponds to a number of bees/ha. This type of HQ calculation is due to the difficulty in transforming pesticide field rates into doses to which bees are exposed. In this study, we used a pragmatic approach to determine the apparent exposure surface area of honey bees submitted to pesticide treatments by spraying with a Potter-type tower. The doses received by the bees were quantified by very efficient chemical analyses, which enabled us to determine an apparent surface area of 1.05 cm(2)/bee. The apparent surface area was used to calculate the exposure levels of bees submitted to pesticide sprays and then to revisit the HQ ratios with a calculation mode similar to that used for all other living species. X-tomography was used to assess the physical surface area of a bee, which was 3.27 cm(2)/bee, and showed that the apparent exposure surface was not overestimated. The control experiments showed that the toxicity induced by doses calculated with the exposure surface area was similar to that induced by treatments according to the European testing procedure. This new approach to measure risk is more accurate and could become a tool to aid the decision-making process in the risk assessment of pesticides.

  14. A Pragmatic Approach to Assess the Exposure of the Honey Bee (Apis mellifera) When Subjected to Pesticide Spray

    PubMed Central

    Poquet, Yannick; Bodin, Laurent; Tchamitchian, Marc; Fusellier, Marion; Giroud, Barbara; Lafay, Florent; Buleté, Audrey; Tchamitchian, Sylvie; Cousin, Marianne; Pélissier, Michel; Brunet, Jean-Luc; Belzunces, Luc P.

    2014-01-01

    Plant protection spray treatments may expose non-target organisms to pesticides. In the pesticide registration procedure, the honey bee represents one of the non-target model species for which the risk posed by pesticides must be assessed on the basis of the hazard quotient (HQ). The HQ is defined as the ratio between environmental exposure and toxicity. For the honey bee, the HQ calculation is not consistent because it corresponds to the ratio between the pesticide field rate (in mass of pesticide/ha) and LD50 (in mass of pesticide/bee). Thus, in contrast to all other species, the HQ can only be interpreted empirically because it corresponds to a number of bees/ha. This type of HQ calculation is due to the difficulty in transforming pesticide field rates into doses to which bees are exposed. In this study, we used a pragmatic approach to determine the apparent exposure surface area of honey bees submitted to pesticide treatments by spraying with a Potter-type tower. The doses received by the bees were quantified by very efficient chemical analyses, which enabled us to determine an apparent surface area of 1.05 cm2/bee. The apparent surface area was used to calculate the exposure levels of bees submitted to pesticide sprays and then to revisit the HQ ratios with a calculation mode similar to that used for all other living species. X-tomography was used to assess the physical surface area of a bee, which was 3.27 cm2/bee, and showed that the apparent exposure surface was not overestimated. The control experiments showed that the toxicity induced by doses calculated with the exposure surface area was similar to that induced by treatments according to the European testing procedure. This new approach to measure risk is more accurate and could become a tool to aid the decision-making process in the risk assessment of pesticides. PMID:25412103

  15. Estimation of Apple Intake for the Exposure Assessment of Residual Chemicals Using Korea National Health and Nutrition Examination Survey Database

    PubMed Central

    2016-01-01

    The aims of this study were to develop strategies and algorithms of calculating food commodity intake suitable for exposure assessment of residual chemicals by using the food intake database of Korea National Health and Nutrition Examination Survey (KNHANES). In this study, apples and their processed food products were chosen as a model food for accurate calculation of food commodity intakes uthrough the recently developed Korea food commodity intake calculation (KFCIC) software. The average daily intakes of total apples in Korea Health Statistics were 29.60 g in 2008, 32.40 g in 2009, 34.30 g in 2010, 28.10 g in 2011, and 24.60 g in 2012. The average daily intakes of apples by KFCIC software was 2.65 g higher than that by Korea Health Statistics. The food intake data in Korea Health Statistics might have less reflected the intake of apples from mixed and processed foods than KFCIC software has. These results can affect outcome of risk assessment for residual chemicals in foods. Therefore, the accurate estimation of the average daily intake of food commodities is very important, and more data for food intakes and recipes have to be applied to improve the quality of data. Nevertheless, this study can contribute to the predictive estimation of exposure to possible residual chemicals and subsequent analysis for their potential risks. PMID:27152299

  16. Estimation of Apple Intake for the Exposure Assessment of Residual Chemicals Using Korea National Health and Nutrition Examination Survey Database.

    PubMed

    Kim, Bumsik; Baek, Min-Seok; Lee, Yongmin; Paik, Jean Kyung; Chang, Moon-Ik; Rhee, Gyu-Seek; Ko, Sanghoon

    2016-04-01

    The aims of this study were to develop strategies and algorithms of calculating food commodity intake suitable for exposure assessment of residual chemicals by using the food intake database of Korea National Health and Nutrition Examination Survey (KNHANES). In this study, apples and their processed food products were chosen as a model food for accurate calculation of food commodity intakes uthrough the recently developed Korea food commodity intake calculation (KFCIC) software. The average daily intakes of total apples in Korea Health Statistics were 29.60 g in 2008, 32.40 g in 2009, 34.30 g in 2010, 28.10 g in 2011, and 24.60 g in 2012. The average daily intakes of apples by KFCIC software was 2.65 g higher than that by Korea Health Statistics. The food intake data in Korea Health Statistics might have less reflected the intake of apples from mixed and processed foods than KFCIC software has. These results can affect outcome of risk assessment for residual chemicals in foods. Therefore, the accurate estimation of the average daily intake of food commodities is very important, and more data for food intakes and recipes have to be applied to improve the quality of data. Nevertheless, this study can contribute to the predictive estimation of exposure to possible residual chemicals and subsequent analysis for their potential risks. PMID:27152299

  17. Estimation of Apple Intake for the Exposure Assessment of Residual Chemicals Using Korea National Health and Nutrition Examination Survey Database.

    PubMed

    Kim, Bumsik; Baek, Min-Seok; Lee, Yongmin; Paik, Jean Kyung; Chang, Moon-Ik; Rhee, Gyu-Seek; Ko, Sanghoon

    2016-04-01

    The aims of this study were to develop strategies and algorithms of calculating food commodity intake suitable for exposure assessment of residual chemicals by using the food intake database of Korea National Health and Nutrition Examination Survey (KNHANES). In this study, apples and their processed food products were chosen as a model food for accurate calculation of food commodity intakes uthrough the recently developed Korea food commodity intake calculation (KFCIC) software. The average daily intakes of total apples in Korea Health Statistics were 29.60 g in 2008, 32.40 g in 2009, 34.30 g in 2010, 28.10 g in 2011, and 24.60 g in 2012. The average daily intakes of apples by KFCIC software was 2.65 g higher than that by Korea Health Statistics. The food intake data in Korea Health Statistics might have less reflected the intake of apples from mixed and processed foods than KFCIC software has. These results can affect outcome of risk assessment for residual chemicals in foods. Therefore, the accurate estimation of the average daily intake of food commodities is very important, and more data for food intakes and recipes have to be applied to improve the quality of data. Nevertheless, this study can contribute to the predictive estimation of exposure to possible residual chemicals and subsequent analysis for their potential risks.

  18. Assessment of potential asbestos exposures from jet engine overhaul work.

    PubMed

    Mlynarek, S P; Van Orden, D R

    2012-06-01

    Asbestos fibers have been used in a wide variety of products and numerous studies have shown that exposures from the use or manipulation of these products can vary widely. Jet engines contained various components (gaskets, clamps, o-rings and insulation) that contained asbestos that potentially could release airborne fibers during routine maintenance or during an engine overhaul. To evaluate the potential exposures to aircraft mechanics, a Pratt & Whitney JT3D jet engine was obtained and overhauled by experienced mechanics using tools and work practices similar to those used since the time this engine was manufactured. This study has demonstrated that the disturbance of asbestos-containing gaskets, o-rings, and other types of asbestos-containing components, while performing overhaul work to a jet engine produces very few airborne fibers, and that virtually none of these aerosolized fibers is asbestos. The overhaul work was observed to be dirty and oily. The exposures to the mechanics and bystanders were several orders of magnitude below OSHA exposure regulations, both current and historic. The data presented underscore the lack of risk to the health of persons conducting this work and to other persons in proximity to it from airborne asbestos.

  19. Assessment of potential asbestos exposures from jet engine overhaul work.

    PubMed

    Mlynarek, S P; Van Orden, D R

    2012-06-01

    Asbestos fibers have been used in a wide variety of products and numerous studies have shown that exposures from the use or manipulation of these products can vary widely. Jet engines contained various components (gaskets, clamps, o-rings and insulation) that contained asbestos that potentially could release airborne fibers during routine maintenance or during an engine overhaul. To evaluate the potential exposures to aircraft mechanics, a Pratt & Whitney JT3D jet engine was obtained and overhauled by experienced mechanics using tools and work practices similar to those used since the time this engine was manufactured. This study has demonstrated that the disturbance of asbestos-containing gaskets, o-rings, and other types of asbestos-containing components, while performing overhaul work to a jet engine produces very few airborne fibers, and that virtually none of these aerosolized fibers is asbestos. The overhaul work was observed to be dirty and oily. The exposures to the mechanics and bystanders were several orders of magnitude below OSHA exposure regulations, both current and historic. The data presented underscore the lack of risk to the health of persons conducting this work and to other persons in proximity to it from airborne asbestos. PMID:22401880

  20. Environmental chemical mixtures: Assessing ecological exposure and effects in streams

    EPA Science Inventory

    This product is a USGS fact sheet that describes a collaborative effort between USGS and US EPA to characterize exposures to chemical mixtures and associated biological effects for a diverse range of US streams representing varying watershed size, land-use patterns, and ecotypes.

  1. DEVELOPMENT OF DNA MICROARRAYS FOR ECOLOGICAL EXPOSURE ASSESSMENT

    EPA Science Inventory

    EPA/ORD is moving forward with a computational toxicology initiative in FY 04 which aims to integrate genomics and computational methods to provide a mechanistic basis for prediction of exposure and effects of chemical stressors in the environment.

    The goal of the presen...

  2. 30 CFR 62.110 - Noise exposure assessment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... must: (i) Be made without adjustment for the use of any hearing protector; (ii) Integrate all sound... Cn is the total time the miner is exposed at a specified sound level, and Tn is the reference duration of exposure at that sound level shown in Table 62-1. (1) The mine operator must use Table...

  3. Assessing elemental mercury vapor exposure from cultural and religious practices.

    PubMed Central

    Riley, D M; Newby, C A; Leal-Almeraz, T O; Thomas, V M

    2001-01-01

    Use of elemental mercury in certain cultural and religious practices can cause high exposures to mercury vapor. Uses include sprinkling mercury on the floor of a home or car, burning it in a candle, and mixing it with perfume. Some uses can produce indoor air mercury concentrations one or two orders of magnitude above occupational exposure limits. Exposures resulting from other uses, such as infrequent use of a small bead of mercury, could be well below currently recognized risk levels. Metallic mercury is available at almost all of the 15 botanicas visited in New York, New Jersey, and Pennsylvania, but botanica personnel often deny having mercury for sale when approached by outsiders to these religious and cultural traditions. Actions by public health authorities have driven the mercury trade underground in some locations. Interviews indicate that mercury users are aware that mercury is hazardous, but are not aware of the inhalation exposure risk. We argue against a crackdown by health authorities because it could drive the practices further underground, because high-risk practices may be rare, and because uninformed government intervention could have unfortunate political and civic side effects for some Caribbean and Latin American immigrant groups. We recommend an outreach and education program involving religious and community leaders, botanica personnel, and other mercury users. PMID:11564612

  4. Assessing elemental mercury vapor exposure from cultural and religious practices.

    PubMed

    Riley, D M; Newby, C A; Leal-Almeraz, T O; Thomas, V M

    2001-08-01

    Use of elemental mercury in certain cultural and religious practices can cause high exposures to mercury vapor. Uses include sprinkling mercury on the floor of a home or car, burning it in a candle, and mixing it with perfume. Some uses can produce indoor air mercury concentrations one or two orders of magnitude above occupational exposure limits. Exposures resulting from other uses, such as infrequent use of a small bead of mercury, could be well below currently recognized risk levels. Metallic mercury is available at almost all of the 15 botanicas visited in New York, New Jersey, and Pennsylvania, but botanica personnel often deny having mercury for sale when approached by outsiders to these religious and cultural traditions. Actions by public health authorities have driven the mercury trade underground in some locations. Interviews indicate that mercury users are aware that mercury is hazardous, but are not aware of the inhalation exposure risk. We argue against a crackdown by health authorities because it could drive the practices further underground, because high-risk practices may be rare, and because uninformed government intervention could have unfortunate political and civic side effects for some Caribbean and Latin American immigrant groups. We recommend an outreach and education program involving religious and community leaders, botanica personnel, and other mercury users.

  5. HESI EXPOSURE FACTORS DATABASE FOR AGGREGATE AND CUMULATIVE RISK ASSESSMENT

    EPA Science Inventory

    In recent years, the risk analysis community has broadened its use of complex aggregate and cumulative residential exposure models (e.g., to meet the requirements of the 1996 Food Quality Protection Act). The value of these models is their ability to incorporate a range of inp...

  6. Assessing Sources of Human Methylmercury Exposure Using Stable Mercury Isotopes

    PubMed Central

    2015-01-01

    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 δ202Hg values between pilot whale muscle tissue and Faroese whalers’ hair but no mass-independent fractionation. We found a similar offset in δ202Hg 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 MeHg exposure sources and confirmed that both Δ199Hg and δ202Hg values in human hair can help identify dietary MeHg sources. Variability in isotopic signatures among coastal fish consumers in the Gulf of Mexico likely reflects both differences in environmental sources of MeHg to coastal fish and uncertainty in dietary recall data. Additional data are needed to fully refine this approach for individuals with complex seafood consumption patterns. PMID:24967674

  7. Environmental Tobacco Smoke: Measuring Exposures and Assessing Health Effects.

    ERIC Educational Resources Information Center

    National Academy of Sciences - National Research Council, Washington, DC.

    This book evaluates methodologies in epidemiologic and related studies for obtaining measurements of exposure to environmental tobacco smoke (ETS). The book is divided into three parts. The first part discusses physicochemical and toxicological studies of environmental tobacco smoke, including physicochemical nature of smoke and in vivo and in…

  8. Progress in High Throughput Exposure Assessment for Prioritizing Human Exposure to Environmental Chemicals (SRA)

    EPA Science Inventory

    For thousands of chemicals in commerce, there is little or no information about exposure or health and ecological effects. The US Environmental Protection Agency (USEPA) has ongoing research programs to develop and evaluate models that use the often minimal chemical information a...

  9. DOSE-RESPONSE MODELING FOR THE ASSESSMENT OF CUMULATIVE RISK DUE TO EXPOSURE TO N-METHYL CARBAMATE PESTICIDES

    EPA Science Inventory

    The US EPAs N-Methyl Carbamate Cumulative Risk Assessment (NMCRA) assesses the effect on acetylcholine esterase (AChE) activity of exposure to 10 N-methyl carbamate (NMC) pesticides through dietary, drinking water, and residential exposures.

  10. Exposure assessment of oxidant gases and acidic aerosols

    SciTech Connect

    Lioy, P.J.

    1989-01-01

    Clearly the presence of high ozone and acidic species in North America is primarily dependent upon photochemical air pollution. Evidence shows, however, that high acid exposures may occur in specific types of areas of high sulfur fuel use during the winter. At the present time, our concerns about exposure to local populations and regional populations should be directed primarily toward the outdoor activity patterns of individuals in the summer, and how those activity patterns relate to the location, duration, and concentrations of ozone and acid aerosol in photochemical air pollution episodes. Lioy Dyba and Mage et al have examined the activity patterns of children in summer camps. Because they spend more time outside than the normal population, these children form an important group of exercising individuals subject to photochemical pollution exposures. The dose of ozone inhaled by the children in the two camps was within 50% and 25% of the dose inhaled by adults in controlled clinical situations that produced clinically significant decrements in pulmonary function and increased the symptoms after 6.6 hr exposure in a given day. The chamber studies have used only ozone, whereas in the environment this effect may be enhanced by the presence of a complex mixture. The work of Lioy et al in Mendham, New Jersey found that hydrogen ion seemed to play a role in the inability of the children to return immediately to their normal peak expiratory flow rate after exposure. The camp health study conducted in Dunsville, Ontario suggested that children participating in a summer camp where moderate levels of ozone (100 ppb) but high levels of acid (46 micrograms/m3) occurred during an episode had a similar response. Thus, for children or exercising adults who are outdoors for at least one hour or more during a given day, the presence and persistence of oxidants in the environment are of particular concern. 63 references.

  11. A Retrospective Assessment of Occupational Exposure to Elemental Carbon in the U.S. Trucking Industry

    PubMed Central

    Hart, Jaime E.; Laden, Francine; Garshick, Eric; Smith, Thomas J.

    2011-01-01

    Background: Despite considerable epidemiologic evidence about the health effects of chronic exposure to vehicle exhaust, efforts at defining the extent of risk have been limited by the lack of historical exposure measurements suitable for use in epidemiologic studies and for risk assessment. Objectives: We sought to reconstruct exposure to elemental carbon (EC), a marker of diesel and other vehicle exhaust exposure, in a large national cohort of U.S. trucking industry workers. Methods: We identified the predictors of measured exposures based on a statistical model and used this information to extrapolate exposures across the cohort nationally. These estimates were adjusted for changes in work-related conditions over time based on a previous exposure assessment of this industry, and for changes in background levels based on a trend analysis of historical air pollution data, to derive monthly estimates of EC exposure for each job and trucking terminal combination between 1971 and 2000. Results: Occupational exposure to EC declined substantially over time, and we found significant variability in estimated exposures both within and across job groups, trucking terminals, and regions of the United States. Average estimated EC exposures during a typical work shift ranged from < 1 μg/m3 in the lowest exposed category in the 1990s to > 40 μg/m3 for workers in the highest exposed jobs in the 1970s. Conclusions: Our results provide a framework for understanding changes over time in exposure to EC in the U.S. trucking industry. Our assessment should minimize exposure misclassification by capturing variation among terminals and across U.S. regions, and changes over time. PMID:21447452

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

    SciTech Connect

    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.

  13. Assessment of infant exposure to food chemicals: the French Total Diet Study design.

    PubMed

    Hulin, M; Bemrah, N; Nougadère, A; Volatier, J L; Sirot, V; Leblanc, J C

    2014-01-01

    As part of the previous French Total Diet Studies (TDS) focusing on exposure to food chemicals in the population aged 3 years and older, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) launched a specific TDS on infants to complete its overall chemical food safety programme for the general population. More than 500 chemical substances were analysed in food products consumed by children under 3 years old, including nutrients, several endocrine disruptors resulting from human activities (polychlorinated biphenyls, dioxins and furans, brominated flame retardants, perfluoroalkyl acids, pesticide residues, etc.) or migrating from food contact materials such as bisphenol A or phthalates, but also natural substances such as mycotoxins, phytoestrogens and steroids. To obtain a representative and general view of infant food consumption, food items were selected based on results of a national consumption survey conducted specifically on this population. Moreover, a specific study on food was conducted on 429 households to determine which home-cooking practices are employed to prepare food consumed by infants. Overall, the targeted chemical substances were analysed in more than 450 food samples, representing the purchase and home-cooking practices of over 5500 food products. Foods included common foods such as vegetables, fruit or cakes as well as specific infant foods such as infant formula or jarred baby food. The sampling plan covered over 80% of the total diet. Specificities in infant food consumption and habits were therefore considered to define this first infant TDS. This study, conducted on a large scale and focusing on a particularly sensitive population, will provide accurate information on the dietary exposure of children under 3 years to food chemicals, especially endocrine disruptors, and will be particularly useful for risk assessment analysis under the remit of ANSES' expert committees.

  14. Integrating Human Indoor Air Pollutant Exposure within Life Cycle Impact Assessment

    SciTech Connect

    Hellweg, Stefanie; Demou, Evangelia; Bruzzi, Raffaella; Meijer, Arjen; Rosenbaum, Ralph K.; Huijbregts, Mark A.J.; McKone, Thomas E.

    2008-12-21

    Neglecting health effects from indoor pollutant emissions and exposure, as currently done in Life Cycle Assessment (LCA), may result in product or process optimizations at the expense of workers? or consumers? health. To close this gap, methods for considering indoor exposure to chemicals are needed to complement the methods for outdoor human exposure assessment already in use. This paper summarizes the work of an international expert group on the integration of human indoor and outdoor exposure in LCA, within the UNEP/SETAC Life Cycle Initiative. A new methodological framework is proposed for a general procedure to include human-health effects from indoor exposure in LCA. Exposure models from occupational hygiene and household indoor air quality studies and practices are critically reviewed and recommendations are provided on the appropriateness of various model alternatives in the context of LCA. A single-compartment box model is recommended for use as a default in LCA, enabling one to screen occupational and household exposures consistent with the existing models to assess outdoor emission in a multimedia environment. An initial set of model parameter values was collected. The comparison between indoor and outdoor human exposure per unit of emission shows that for many pollutants, intake per unit of indoor emission may be several orders of magnitude higher than for outdoor emissions. It is concluded that indoor exposure should be routinely addressed within LCA.

  15. A task-based approach to assessing lead exposure among iron workers engaged in bridge rehabilitation.

    PubMed

    Goldberg, M; Levin, S M; Doucette, J T; Griffin, G

    1997-03-01

    The assessment of worker exposures to airborne contaminants in the dynamic environment present at most construction sites poses considerable challenges to the industrial hygienist. In this study, we applied a task-based approach to the assessment of lead exposure among structural steel iron workers engaged in a large, complex bridge rehabilitation project. We evaluated the usefulness of task-based exposure data for the development of worker protection programs. Task-specific and multitask samples were collected, and operation-specific and 8-hr time-weighted averages were calculated. The task-specific data showed significant differences in exposure levels among different tasks. Arithmetic mean exposures varied from 1,357 micrograms/m3 lead for torch cutting and 989 micrograms/m3 for scaling to 31 micrograms/m3 for reaming and 4 micrograms/m3 for drilling. Our task-specific data were compared with the task-based exposure levels presented by OSHA in its Lead Exposure in Construction-Interim Final Rule (29 CFR 1926). There was good general agreement between our results and OSHA's reported data. Task-based data were very useful in exposure assessment and much more precise than full-shift and operation-based measurements in guiding strategies for worker protection. These findings suggest that task-based data should routinely be collected in evaluating exposure to lead and perhaps other toxic substances in construction work.

  16. THE NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY (NHEXAS) STUDY IN ARIZONA-INTRODUCTION AND PRELIMINARY RESULTS

    EPA Science Inventory

    The objective of the National Human Exposure Assessment Survey (NHEXAS) in Arizona is to determine the multimedia distribution of total human exposure to environmental pollutants in the classes of metals, pesticides, and volatile organic compounds (VOCs) for the population of Ari...

  17. Assessment of Secondhand Smoke Exposure at School among U.S. Middle and High School Students

    ERIC Educational Resources Information Center

    Olufajo, Olubode Ademola; Agaku, Israel Terungwa

    2015-01-01

    To obtain nationally representative estimates of the prevalence of secondhand smoke (SHS) exposure at U.S. schools, we assessed the prevalence and correlates of SHS exposure at school among U.S. middle and high school students using data from the 2011 National Youth Tobacco Survey comprising of 18,866 students spread across all the U.S. states.…

  18. A FRAMEWORK FOR ASSESSING HEALTH RISK OF ENVIRONMENTAL EXPOSURES TO CHILDREN (FINAL)

    EPA Science Inventory

    EPA has released a final report entitled, A Framework for Assessing Health Risk of Environmental Exposures to Children, which examines the impact of potential exposures during developmental lifestages and subsequent lifestages, while emphasizing the iterative nature of the...

  19. Elemental Speciation as an Essential Part of Formulating Exposure Assessments that Support Risk Estimates

    EPA Science Inventory

    The chemical form specific toxicity of arsenic has caused scientists to move toward species specific assessments with an emphasis on biological relevance of an exposure. For example, numerous studies on the occurrence of arsenic in rice have documented the exposure potential fro...

  20. Probabilistic assessment of exposure to hair cosmetic products by the French population.

    PubMed

    Ficheux, A S; Bernard, A; Chevillotte, G; Dornic, N; Roudot, A C

    2016-06-01

    Cosmetic exposure data are limited in Europe and especially in France. The aim of this study was to assess the exposure to hair cosmetics using recent consumption data (percentage of users, frequency of use and amount per use) generated for the French population (Ficheux et al., 2015, 2016). Exposure was assessed using a probabilistic method for eleven hair products: liquid shampoo, dry shampoo, conditioner, hair mask, hair serum, hair oil, styling lacquer, styling gel, styling foam, styling wax and styling spray. Exposure was assessed by sex and by age classes in adults and children. Pregnant women were also studied. For liquid shampoo, conditioner and some styling products (gel, lacquer and foam), the levels of exposure were higher than the values currently used by the Scientific Committee on Consumer Safety (SCCS). Exposure values found for styling wax and styling spray were lower than SCCS values. Exposure was assessed for the first time for dry shampoo, hair mask, hair serum and hair oil products. These new French exposure values will be useful for safety assessors and for safety agencies in order to protect the general population and these at-risk populations. PMID:27090106

  1. RESPIRATORY DOSE TO SUSCEPTIBLE POPULATIONS ASSESSED BY EXPOSURE AND DOSIMETRY STUDIES

    EPA Science Inventory

    Respiratory Dose to Susceptible Populations Assessed by Exposure and Dosimetry Studies

    Chong Kim1 and Ronald Williams2, 1USEPA National Health and Environmental Effects Research Laboratory and 2USEPA National Exposure Research Laboratory, RTP, NC.

    Rationale: Parti...

  2. Instruments to assess and measure personal and environmental radiofrequency-electromagnetic field exposures.

    PubMed

    Bhatt, Chhavi Raj; Redmayne, Mary; Abramson, Michael J; Benke, Geza

    2016-03-01

    Radiofrequency-electromagnetic field (RF-EMF) exposure of human populations is increasing due to the widespread use of mobile phones and other telecommunication and broadcasting technologies. There are ongoing concerns about potential short- and long-term public health consequences from RF-EMF exposures. To elucidate the RF-EMF exposure-effect relationships, an objective evaluation of the exposures with robust assessment tools is necessary. This review discusses and compares currently available RF-EMF exposure assessment instruments, which can be used in human epidemiological studies. Quantitative assessment instruments are either mobile phone-based (apps/software-modified and hardware-modified) or exposimeters. Each of these tool has its usefulness and limitations. Our review suggests that assessment of RF-EMF exposures can be improved by using these tools compared to the proxy measures of exposure (e.g. questionnaires and billing records). This in turn, could be used to help increase knowledge about RF-EMF exposure induced health effects in human populations. PMID:26684750

  3. STRATEGIC PLAN FOR THE ANALYSIS OF THE NATIONAL HUMAN EXPOSURE ASSESSMENT SURVEY (NHEXAS) PILOT STUDY DATA

    EPA Science Inventory

    The Office of Research and Development (ORD) of the U.S. Environmental Protection Agency (EPA) initiated the National Human Exposure Assessment Survey (NHEXAS) in the early 1990's. It was a population-based pilot study of the exposure of over 500 people in three areas of the U....

  4. A National Assessment of Sea Level Rise Exposure Using Lidar Elevation Data

    NASA Astrophysics Data System (ADS)

    Strauss, B.; Kulp, S. A.; Tebaldi, C.

    2014-12-01

    The Third National Climate Assessment addressed sea level rise and aggravated coastal flood exposure in all regions, but was completed before high quality lidar-based elevation data became available throughout the entire coastal United States (excluding Alaska). Here we present what we believe to be the first full national assessment incorporating these data. The assessment includes tabulation of land less than 1-6 m above the local high tide line, and of a wide range of features sitting on that land, including total population, socially vulnerable population, housing, property value, road miles, power plants, schools, hospitals, and a wide range of other infrastructure and critical facilities, as well as EPA-listed facilities that are potential sources of contamination during floods or permanent inundation. Tabulations span from zip code to national levels. Notable patterns include the strong concentration of exposure across multiple scales, with a small number of states accounting for most of the total national exposure; and a small number of zip codes accounting for a large proportion of the exposure within many states. Additionally, different features show different exposure patterns; in one example, land and road miles have relatively high exposure but population and property have relatively low exposure in North Carolina. The assessment further places this exposure analysis in the context of localized sea level rise projections integrated with coastal flood risk.

  5. Full Mission Astronaut Radiation Exposure Assessments for Long Duration Lunar Surface Missions

    NASA Technical Reports Server (NTRS)

    Adamczyk, Anne; Clowdsley, Martha; Qualls, Garry; Blattnig, Steve; Lee, Kerry; Fry, Dan; Stoffle, Nicholas; Simonsen, Lisa; Slaba, Tony; Walker, Steven; Zapp, Edward

    2011-01-01

    Risk to astronauts due to ionizing radiation exposure is a primary concern for missions beyond Low Earth Orbit (LEO) and will drive mission architecture requirements, mission timelines, and operational practices. For short missions, radiation risk is dominated by the possibility of a large Solar Particle Event (SPE). Longer duration missions have both SPE and Galactic Cosmic Ray (GCR) risks. SPE exposure can contribute significantly toward cancer induction in combination with GCR. As mission duration increases, mitigation strategies must address the combined risks from SPE and GCR exposure. In this paper, full mission exposure assessments were performed for the proposed long duration lunar surface mission scenarios. In order to accomplish these assessments, previously developed radiation shielding models for a proposed lunar habitat and rover were utilized. End-to-End mission exposure assessments were performed by first calculating exposure rates for locations in the habitat, rover, and during Extra-Vehicular Activities (EVA). Subsequently, total mission exposures were evaluated for the proposed timelines. Mission exposure results, assessed in terms of effective dose, are presented for the proposed timelines and recommendations are made for improved astronaut shielding and safer operational practices.

  6. EXPOSURE ASSESSMENT TO DIOXINS FROM THE USE OF TAMPONS AND DIAPERS

    EPA Science Inventory

    Exposure Assessment to Dioxins from the Use of Tampons and Diapers
    Michael J. DeVito and Arnold Schecter
    Abstract
    Methods: Four brands of tampons and four brands of infant diapers were analyzed for dioxin concentrations. Exposures to dioxins were modeled using parti...

  7. Probabilistic assessment of exposure to hair cosmetic products by the French population.

    PubMed

    Ficheux, A S; Bernard, A; Chevillotte, G; Dornic, N; Roudot, A C

    2016-06-01

    Cosmetic exposure data are limited in Europe and especially in France. The aim of this study was to assess the exposure to hair cosmetics using recent consumption data (percentage of users, frequency of use and amount per use) generated for the French population (Ficheux et al., 2015, 2016). Exposure was assessed using a probabilistic method for eleven hair products: liquid shampoo, dry shampoo, conditioner, hair mask, hair serum, hair oil, styling lacquer, styling gel, styling foam, styling wax and styling spray. Exposure was assessed by sex and by age classes in adults and children. Pregnant women were also studied. For liquid shampoo, conditioner and some styling products (gel, lacquer and foam), the levels of exposure were higher than the values currently used by the Scientific Committee on Consumer Safety (SCCS). Exposure values found for styling wax and styling spray were lower than SCCS values. Exposure was assessed for the first time for dry shampoo, hair mask, hair serum and hair oil products. These new French exposure values will be useful for safety assessors and for safety agencies in order to protect the general population and these at-risk populations.

  8. 43 CFR 11.37 - Must the authorized official confirm exposure before implementing the Assessment Plan?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... authorized official confirm exposure before implementing the Assessment Plan? (a) Before including any type B... data, such as those collected for response actions by the OSC, or other available studies or surveys of... analyses shall be limited to the number and type required for confirmation of exposure. (3) Where...

  9. Refinement of the Nanoparticle Emission Assessment Technique into the Nanomaterial Exposure Assessment Technique (NEAT 2.0)

    PubMed Central

    Eastlake, Adrienne C; Beaucham, Catherine; Martinez, Kenneth F; Dahm, Matthew M; Sparks, Christopher; Hodson, Laura L; Geraci, Charles L

    2016-01-01

    Engineered nanomaterial emission and exposure characterization studies have been completed at more than 60 different facilities by the National Institute for Occupational Safety and Health (NIOSH). These experiences have provided NIOSH the opportunity to refine an earlier published technique, the Nanoparticle Emission Assessment Technique (NEAT 1.0), into a more comprehensive technique for assessing worker and workplace exposures to engineered nanomaterials. This change is reflected in the new name Nanomaterial Exposure Assessment Technique (NEAT 2.0) which distinguishes it from NEAT 1.0. NEAT 2.0 places a stronger emphasis on time-integrated, filter-based sampling (i.e., elemental mass analysis and particle morphology) in the worker's breathing zone (full shift and task specific) and area samples to develop job exposure matrices. NEAT 2.0 includes a comprehensive assessment of emissions at processes and job tasks, using direct-reading instruments (i.e., particle counters) in data-logging mode to better understand peak emission periods. Evaluation of worker practices, ventilation efficacy, and other engineering exposure control systems and risk management strategies serve to allow for a comprehensive exposure assessment. PMID:27027845

  10. Refinement of the Nanoparticle Emission Assessment Technique into the Nanomaterial Exposure Assessment Technique (NEAT 2.0).

    PubMed

    Eastlake, Adrienne C; Beaucham, Catherine; Martinez, Kenneth F; Dahm, Matthew M; Sparks, Christopher; Hodson, Laura L; Geraci, Charles L

    2016-09-01

    Engineered nanomaterial emission and exposure characterization studies have been completed at more than 60 different facilities by the National Institute for Occupational Safety and Health (NIOSH). These experiences have provided NIOSH the opportunity to refine an earlier published technique, the Nanoparticle Emission Assessment Technique (NEAT 1.0), into a more comprehensive technique for assessing worker and workplace exposures to engineered nanomaterials. This change is reflected in the new name Nanomaterial Exposure Assessment Technique (NEAT 2.0) which distinguishes it from NEAT 1.0. NEAT 2.0 places a stronger emphasis on time-integrated, filter-based sampling (i.e., elemental mass analysis and particle morphology) in the worker's breathing zone (full shift and task specific) and area samples to develop job exposure matrices. NEAT 2.0 includes a comprehensive assessment of emissions at processes and job tasks, using direct-reading instruments (i.e., particle counters) in data-logging mode to better understand peak emission periods. Evaluation of worker practices, ventilation efficacy, and other engineering exposure control systems and risk management strategies serve to allow for a comprehensive exposure assessment.

  11. [Exposure to VHF and UHF electromagnetic fields among workers employed in radio and TV broadcast centers. I. Assessment of exposure].

    PubMed

    Zmyślony, M; Aniołczyk, H; Bortkiewicz, A

    2001-01-01

    Nowadays, radio and television have become one of the areas of the human technical activity that develops most rapidly. Also ultra-short waves of VHF (30-300 MHz) and UHF (0.3-3 GHz) bands have proved to be the most important carriers of radio and TV-programs. In Poland, a network of radio and TV broadcast centers (RTCN) with high (over 200 m) masts was set up in the 1960s and 1970s. These centers concentrate the majority of stations broadcasting national and local programs (for areas within the RTCN range). At present, the RTCN established several decades ago are equally important. The assessment of the exposure to electromagnetic fields among workers of multi-program broadcast stations is complicated and feasible only to a certain degree of approximation because of changing conditions of exposure in individual stations during their long history, resulting from the changing numbers and types of transmitters installed. In this work, the method of retrospective estimation of exposure dose is described, and the results of the assessment carried out at three kinds of typical RTCN are discussed. The results of the analysis indicate that the workers of RTCN are exposed primarily to electromagnetic fields of VHF and UHF bands, but this exposure may be considered as admissible, hence it should not exert an adverse effect on the workers' health. PMID:11828845

  12. REACH exposure assessment of anticorrosive paint products--determination of exposure from application and service life to the aquatic environment.

    PubMed

    Gade, Anne Lill; Heiaas, Harald; Thomas, Kevin; Hylland, Ketil

    2011-12-01

    The European Community Regulation on the registration, evaluation, authorisation and restriction of chemicals (REACH) introduced exposure scenarios describing safe use quantitatively, and enhancing the importance of scientific based exposure assessments. This paper presents methods to determine exposure from the airless spray application of anti-corrosive paint and leaching of painted articles submerged in seawater, to establish whether it is possible to test these exposures in a reproducible and feasible way. The paper also presents results from using the methods in order to assess how well the default values recommended under REACH coincide with the tested values and corresponding values available in literature. The methods used were feasible under laboratory conditions. The reproducibility of the application study was shown to be good and all analyses of the leaching showed concentrations below detection limit. More replicates will be required to validate the reproducibility of the growth inhibition tests. Measured values for the present overspray scenario were between, and the leaching values below, values from REACH guidelines and emission scenario documents. Further development of the methods is recommended. PMID:21964505

  13. Indoor transformer stations and ELF magnetic field exposure: use of transformer structural characteristics to improve exposure assessment.

    PubMed

    Okokon, Enembe Oku; Roivainen, Päivi; Kheifets, Leeka; Mezei, Gabor; Juutilainen, Jukka

    2014-01-01

    Previous studies have shown that populations of multiapartment buildings with indoor transformer stations may serve as a basis for improved epidemiological studies on the relationship between childhood leukaemia and extremely-low-frequency (ELF) magnetic fields (MFs). This study investigated whether classification based on structural characteristics of the transformer stations would improve ELF MF exposure assessment. The data included MF measurements in apartments directly above transformer stations ("exposed" apartments) in 30 buildings in Finland, and reference apartments in the same buildings. Transformer structural characteristics (type and location of low-voltage conductors) were used to classify exposed apartments into high-exposure (HE) and intermediate-exposure (IE) categories. An exposure gradient was observed: both the time-average MF and time above a threshold (0.4 μT) were highest in the HE apartments and lowest in the reference apartments, showing a statistically significant trend. The differences between HE and IE apartments, however, were not statistically significant. A simulation exercise showed that the three-category classification did not perform better than a two-category classification (exposed and reference apartments) in detecting the existence of an increased risk. However, data on the structural characteristics of transformers is potentially useful for evaluating exposure-response relationship.

  14. Evaluating Exposures to Chemical and Non-Chemical Stressors in a Cumulative Risk Assessment

    EPA Science Inventory

    Characteristically toxicological and epidemiological studies involving chemical mixtures (e.g., multi-pollutant exposures) have been increasing. Human health assessment of chemical and nonchemical mixture risk remains rare. Recently, there has been an increased emphasis on integr...

  15. Modeling Joint Exposures and Health Outcomes for Cumulative Risk Assessment: the Case of Radon and Smoking

    EPA Science Inventory

    Community-based cumulative risk assessment requires characterization of exposures to multiple chemical and non-chemical stressors, with consideration of how the non-chemical stressors may influence risks from chemical stressors. Residential radon provides an interesting case exam...

  16. The influence of clinicians' previous trauma exposure on their assessment of child abuse risk.

    PubMed

    Regehr, Cheryl; LeBlanc, Vicki; Shlonsky, Aron; Bogo, Marion

    2010-09-01

    Research has identified high levels of trauma exposure and PTSD in professionals responsible for assessing children at risk for abuse. An important question arising is the influence of stress and trauma on professional judgment. This study examined the association between critical incident exposure, PTSD and workers' judgments of child risk. Ninety-six child protection workers participated in 2 simulated clinical interviews and subsequently completed standardized risk assessment measures. Workers reported high levels of exposure to critical events in the workplace and high levels of traumatic stress symptoms. Number of prior critical events encountered was negatively associated with assessment of risk. Level of traumatic stress symptoms was negatively associated with risk on one, but not other measures of risk. It is concluded that standardized measures for assessing a child's risk of abuse may be influenced by previous exposure to critical workplace events and levels of traumatic stress in workers. PMID:20823721

  17. The Future of Exposure Assessment: Perspectives from the X2012 Conference

    EPA Science Inventory

    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 (...

  18. RECENT DEVELOPMENTS IN EXHALED BREATH ANALYSIS AND HUMAN EXPOSURE ASSESSMENT RESEARCH

    EPA Science Inventory

    This presentation will explore historical and newly emerging methods for the collection and analysis of exhaled breath for use in environmental exposure assessment studies. We will discuss their applicability and limitations with respect to environmental research. Particular em...

  19. Chronic disease and early exposure to air-borne mixtures. 2. Exposure assessment

    SciTech Connect

    James Argo

    2007-10-15

    This work is part of a larger study of the impact of early exposure to releases from industry on the etiology of cancer. Releases from all kraft and sulfite mills, coke ovens, oil refineries, copper, nickel, and lead/zinc smelters operating in Canada during the exposure period of 1967-1970 have been determined. All plumes have been expressed in g BaP eq/d using the RASH methodology. The releases have been divided into process, boiler fuel, dioxin, and SO{sub 2} emissions. Combustion sources have been defined with FIREv6.23. Dioxin congenors are expected in all source types when the boiler fuel is heavy fuel oil, wood or wood bark, or coal. All about 90 communities examined have an inverted sex ratio. 53 refs., 2 figs., 4 tabs.

  20. The Utility of Maze Accurate Response Rate in Assessing Reading Comprehension in Upper Elementary and Middle School Students

    ERIC Educational Resources Information Center

    McCane-Bowling, Sara J.; Strait, Andrea D.; Guess, Pamela E.; Wiedo, Jennifer R.; Muncie, Eric

    2014-01-01

    This study examined the predictive utility of five formative reading measures: words correct per minute, number of comprehension questions correct, reading comprehension rate, number of maze correct responses, and maze accurate response rate (MARR). Broad Reading cluster scores obtained via the Woodcock-Johnson III (WJ III) Tests of Achievement…

  1. Radiation exposure assessment for portsmouth naval shipyard health studies.

    PubMed

    Daniels, R D; Taulbee, T D; Chen, P

    2004-01-01

    Occupational radiation exposures of 13,475 civilian nuclear shipyard workers were investigated as part of a retrospective mortality study. Estimates of annual, cumulative and collective doses were tabulated for future dose-response analysis. Record sets were assembled and amended through range checks, examination of distributions and inspection. Methods were developed to adjust for administrative overestimates and dose from previous employment. Uncertainties from doses below the recording threshold were estimated. Low-dose protracted radiation exposures from submarine overhaul and repair predominated. Cumulative doses are best approximated by a hybrid log-normal distribution with arithmetic mean and median values of 20.59 and 3.24 mSv, respectively. The distribution is highly skewed with more than half the workers having cumulative doses <10 mSv and >95% having doses <100 mSv. The maximum cumulative dose is estimated at 649.39 mSv from 15 person-years of exposure. The collective dose was 277.42 person-Sv with 96.8% attributed to employment at Portsmouth Naval Shipyard. PMID:15266069

  2. Assessment of noise exposure for indoor and outdoor firing ranges.

    PubMed

    Murphy, William J; Tubbs, Randy L

    2007-09-01

    The National Institute for Occupational Safety and Health (NIOSH) received an employee request for a health hazard evaluation of a Special Weapons Assault Team (SWAT) in January 2002. The department was concerned about noise exposures and potential hearing damage from weapons training on their indoor and outdoor firing ranges. NIOSH investigators conducted noise sampling with an acoustic mannequin head and 1/4 -inch microphone to characterize the noise exposures that officers might experience during small arms qualification and training when wearing a variety of hearing protection devices provided by the department. The peak sound pressure levels for the various weapons ranged from 156 to 170 decibels (dB SPL), which are greater than the recommended allowable 140 dB SPL exposure guideline from NIOSH. The earplugs, ear muffs, and customized SWAT team hearing protectors provided between 25 and 35 dB of peak reduction. Double hearing protection (plugs plus muffs) added 15-20 dB of peak reduction. PMID:17654224

  3. Effect of training, education, professional experience, and need for cognition on accuracy of exposure assessment decision-making.

    PubMed

    Vadali, Monika; Ramachandran, Gurumurthy; Banerjee, Sudipto

    2012-04-01

    accuracy of judgments and the various characteristics describing the participants. Data interpretation training (P < 0.0001), the company that the hygienist worked for (P < 0.0001), the total number of years hygienists had experience doing exposure assessments (P < 0.0001), and professional certifications (P < 0.0001) held by hygienists were found to be significant determinants of accurately predicting the correct exposure category for DITs as well as for task-specific judgment accuracy. Years of experience with a particular task (P < 0.0001), task evaluated, and the number of datapoints used for making judgments were found to be significant predictors of task-specific judgment accuracy. The NFC score was a predictor of the improvement in task judgment accuracy after training. The NFC score was itself predicted by determinants, such as company, years on current job, years of exposure assessment experience, and professional certifications. The results of this study are relevant not only for the case of industrial hygienists making exposure judgments prospectively but also possibly for those hygienists engaged in retrospective exposure assessments for epidemiological studies.

  4. Assessing human exposure to power-frequency electric and magnetic fields.

    PubMed Central

    Kaune, W T

    1993-01-01

    This paper reviews published literature and current problems relating to the assessment of occupational and residential human exposures to power-frequency electric and magnetic fields. Available occupational exposure data suggest that the class of job titles known as electrical workers may be an effective surrogate for time-weighted-average (TWA) magnetic-field (but not electric-field) exposure. Current research in occupational-exposure assessment is directed to the construction of job-exposure matrices based on electric- and magnetic-field measurements and estimates of worker exposures to chemicals and other factors of interest. Recent work has identified five principal sources of residential magnetic fields: electric power transmission lines, electric power distribution lines, ground currents, home wiring, and home appliances. Existing residential-exposure assessments have used one or more of the following techniques: questionnaires, wiring configuration coding, theoretical field calculations, spot electric- and magnetic-field measurements, fixed-site magnetic-field recordings, personal- exposure measurements, and geomagnetic-field measurements. Available normal-power magnetic-field data for residences differ substantially between studies. It is not known if these differences are due to geographical differences, differences in measurement protocols, or instrumentation differences. Wiring codes and measured magnetic fields (but not electric fields) are associated weakly. Available data suggest, but are far from proving, that spot measurements may be more effective than wire codes as predictors of long-term historical magnetic-field exposure. Two studies find that away-from-home TWA magnetic-field exposures are less variable than at-home exposures. The importance of home appliances as contributors to total residential magnetic-field exposure is not known at this time. It also is not known what characteristics (if any) of residential electric and magnetic fields are

  5. Assessment of noise exposure for basketball sports referees.

    PubMed

    Masullo, Massimiliano; Lenzuni, Paolo; Maffei, Luigi; Nataletti, Pietro; Ciaburro, Giuseppe; Annesi, Diego; Moschetto, Antonio

    2016-01-01

    Dosimetric measurements carried out on basketball referees have shown that whistles not only generate very high peak sound pressure levels, but also play a relevant role in determining the overall exposure to noise of the exposed subjects. Because of the peculiar geometry determined by the mutual positions of the whistle, the microphone, and the ear, experimental data cannot be directly compared with existing occupational noise exposure and/or action limits. In this article, an original methodology, which allows experimental results to be reliably compared with the aforementioned limits, is presented. The methodology is based on the use of two correction factors to compensate the effects of the position of the dosimeter microphone (fR) and of the sound source (fS). Correction factors were calculated by means of laboratory measurements for two models of whistles (Fox 40 Classic and Fox 40 Sonik) and for two head orientations (frontal and oblique).Results sho w that for peak sound pressure levels the values of fR and fS, are in the range -8.3 to -4.6 dB and -6.0 to -1.7 dB, respectively. If one considers the Sound Exposure Levels (SEL) of whistle events, the same correction factors are in the range of -8.9 to -5.3 dB and -5.4 to -1.5 dB, respectively. The application of these correction factors shows that the corrected weekly noise exposure level for referees is 80.6 dB(A), which is slightly in excess of the lower action limit of the 2003/10/EC directive, and a few dB below the Recommended Exposure Limit (REL) proposed by the National Institute for Occupational Safety and Health (NIOSH). The corrected largest peak sound pressure level is 134.7 dB(C) which is comparable to the lower action limit of the 2003/10/EC directive, but again substantially lower than the ceiling limit of 140 dB(A) set by NIOSH. PMID:26853828

  6. Assessment of carbon nanoparticle exposure on murine macrophage function

    NASA Astrophysics Data System (ADS)

    Suro-Maldonado, Raquel M.

    There is growing concern about the potential cytotoxicity of nanoparticles. Exposure to respirable ultrafine particles (2.5uM) can adversely affect human health and have been implicated with episodes of increased respiratory diseases such as asthma and allergies. Nanoparticles are of particular interest because of their ability to penetrate into the lung and potentially elicit health effects triggering immune responses. Nanoparticles are structures and devises with length scales in the 1 to 100-nanometer range. Black carbon (BC) nanoparticles have been observed to be products of combustion, especially flame combustion and multi-walled carbon nanotubes (MWCNT) have been shown to be found in both indoor and outdoor air. Furthermore, asbestos, which have been known to cause mesothelioma as well as lung cancer, have been shown to be structurally identical to MWCNTs. The aims of these studies were to examine the effects of carbon nanoparticles on murine macrophage function and clearance mechanisms. Macrophages are immune cells that function as the first line of defense against invading pathogens and are likely to be amongst the first cells affected by nanoparticles. Our research focused on two manufactured nanoparticles, MWCNT and BC. The two were tested against murine-derived macrophages in a chronic contact model. We hypothesized that long-term chronic exposure to carbon nanoparticles would decrease macrophages ability to effectively respond to immunological challenge. Production of nitric oxide (NO), tumor necrosis factor alpha (TNF-alpha), cell surface macrophage; activation markers, reactive oxygen species formation (ROS), and antigen processing and presentation were examined in response to lipopolysaccharide (LPS) following a 144hr exposure to the particulates. Data demonstrated an increase in TNF-alpha, and NO production; a decrease in phagocytosis and antigen processing and presentation; and a decrease in the expression levels of cell surface macrophage

  7. Assessment of noise exposure for basketball sports referees.

    PubMed

    Masullo, Massimiliano; Lenzuni, Paolo; Maffei, Luigi; Nataletti, Pietro; Ciaburro, Giuseppe; Annesi, Diego; Moschetto, Antonio

    2016-01-01

    Dosimetric measurements carried out on basketball referees have shown that whistles not only generate very high peak sound pressure levels, but also play a relevant role in determining the overall exposure to noise of the exposed subjects. Because of the peculiar geometry determined by the mutual positions of the whistle, the microphone, and the ear, experimental data cannot be directly compared with existing occupational noise exposure and/or action limits. In this article, an original methodology, which allows experimental results to be reliably compared with the aforementioned limits, is presented. The methodology is based on the use of two correction factors to compensate the effects of the position of the dosimeter microphone (fR) and of the sound source (fS). Correction factors were calculated by means of laboratory measurements for two models of whistles (Fox 40 Classic and Fox 40 Sonik) and for two head orientations (frontal and oblique).Results sho w that for peak sound pressure levels the values of fR and fS, are in the range -8.3 to -4.6 dB and -6.0 to -1.7 dB, respectively. If one considers the Sound Exposure Levels (SEL) of whistle events, the same correction factors are in the range of -8.9 to -5.3 dB and -5.4 to -1.5 dB, respectively. The application of these correction factors shows that the corrected weekly noise exposure level for referees is 80.6 dB(A), which is slightly in excess of the lower action limit of the 2003/10/EC directive, and a few dB below the Recommended Exposure Limit (REL) proposed by the National Institute for Occupational Safety and Health (NIOSH). The corrected largest peak sound pressure level is 134.7 dB(C) which is comparable to the lower action limit of the 2003/10/EC directive, but again substantially lower than the ceiling limit of 140 dB(A) set by NIOSH.

  8. Approaches to Children’s Exposure Assessment: Case Study with Diethylhexylphthalate (DEHP)

    PubMed Central

    Ginsberg, Gary; Ginsberg, Justine; Foos, Brenda

    2016-01-01

    Children’s exposure assessment is a key input into epidemiology studies, risk assessment and source apportionment. The goals of this article are to describe a methodology for children’s exposure assessment that can be used for these purposes and to apply the methodology to source apportionment for the case study chemical, diethylhexylphthalate (DEHP). A key feature is the comparison of total (aggregate) exposure calculated via a pathways approach to that derived from a biomonitoring approach. The 4-step methodology and its results for DEHP are: (1) Prioritization of life stages and exposure pathways, with pregnancy, breast-fed infants, and toddlers the focus of the case study and pathways selected that are relevant to these groups; (2) Estimation of pathway-specific exposures by life stage wherein diet was found to be the largest contributor for pregnant women, breast milk and mouthing behavior for the nursing infant and diet, house dust, and mouthing for toddlers; (3) Comparison of aggregate exposure by pathways vs biomonitoring-based approaches wherein good concordance was found for toddlers and pregnant women providing confidence in the exposure assessment; (4) Source apportionment in which DEHP presence in foods, children’s products, consumer products and the built environment are discussed with respect to early life mouthing, house dust and dietary exposure. A potential fifth step of the method involves the calculation of exposure doses for risk assessment which is described but outside the scope for the current case study. In summary, the methodology has been used to synthesize the available information to identify key sources of early life exposure to DEHP. PMID:27376320

  9. Methods for assessing the extent of exposure and effects of air pollution.

    PubMed Central

    Krzyzanowski, M

    1997-01-01

    BACKGROUND AND OBJECTIVES: In many places in Europe, the ambient air pollution exceeds the levels considered to be safe for health. The objective of the paper is to review and summarise the methods of assessment of its impact on health, and to indicate the contributions of various research disciplines, particularly environmental epidemiology. METHODS: The framework for assessment of impact is based on a four stage model: assessment of release of pollutant; assessment of exposure; assessment of the consequence; and risk estimation. RESULTS: Epidemiology is crucial in providing the data for the assessment of consequence. The criteria that determine the use of epidemiological studies for this task include lack of bias, correct control of confounding, and measured estimates of exposure. At present, those criteria are easier to satisfy for studies of short term effects on health than for the delayed consequences of exposure, or exposure accumulated over a prolonged period. Combinations of results from various populations through meta-analysis of existing studies or conducting multicentre studies is often necessary to increase the reliability of the consequence assessment stage. CONCLUSION: To assess the impact on health systematically helps to focus on actions to limit air pollutants with the greatest impacts on human health and on the most affected populations. This method allows identification of the most pertinent questions which have to be answered by studies on relations between pollution and health and on exposure of populations to air pollutants. Epidemiology has considerable potential to contribute to this research. PMID:9155775

  10. Residential NOx exposure in a 35-year cohort study. Changes of exposure, and comparison with back extrapolation for historical exposure assessment

    NASA Astrophysics Data System (ADS)

    Molnár, Peter; Stockfelt, Leo; Barregard, Lars; Sallsten, Gerd

    2015-08-01

    In this study we aimed to investigate the effects on historical NOx estimates on time trends, spatial distributions, exposure contrasts, the effect of relocation patterns and the effects of back extrapolation. Historical levels of nitrogen oxides (NOx) from 1975 to 2009 were modeled with high resolution in Gothenburg, Sweden, using historical emission databases and Gaussian models. Yearly historical addresses were collected and geocoded from a population-based cohort of Swedish men from 1973 to 2007, with a total of 160,568 address years. Of these addresses, 146,675 (91%) were within our modeled area and assigned a NOx level. NOx levels decreased substantially from a maximum median level of 43.9 μg m-3 in 1983 to 16.6 μg m-3 in 2007, mainly due to lower emissions per vehicle km. There was a considerable variability in concentrations within the cohort, with a ratio of 3.5 between the means in the highest and lowest quartile. About 50% of the participants changed residential address during the study, but the mean NOx exposure was not affected. About half of these moves resulted in a positive or negative change in NOx exposure of >10 μg m-3, and thus changed the exposure substantially. Back extrapolation of NOx levels using the time trend of a background monitoring station worked well for 5-7 years back in time, but extrapolation more than ten years back in time resulted in substantial scattering compared to the "true" dispersion models for the corresponding years. These findings are important to take into account since accurate exposure estimates are essential in long term epidemiological studies of health effects of air pollution.

  11. Aggregate Exposure and Cumulative Risk Assessment--Integrating Occupational and Non-occupational Risk Factors.

    PubMed

    Lentz, T J; Dotson, G S; Williams, P R D; Maier, A; Gadagbui, B; Pandalai, S P; Lamba, A; Hearl, F; Mumtaz, M

    2015-01-01

    Occupational exposure limits have traditionally focused on preventing morbidity and mortality arising from inhalation exposures to individual chemical stressors in the workplace. While central to occupational risk assessment, occupational exposure limits have limited application as a refined disease prevention tool because they do not account for all of the complexities of the work and non-occupational environments and are based on varying health endpoints. To be of greater utility, occupational exposure limits and other risk management tools could integrate broader consideration of risks from multiple exposure pathways and routes (aggregate risk) as well as the combined risk from exposure to both chemical and non-chemical stressors, within and beyond the workplace, including the possibility that such exposures may cause interactions or modify the toxic effects observed (cumulative risk). Although still at a rudimentary stage in many cases, a variety of methods and tools have been developed or are being used in allied risk assessment fields to incorporate such considerations in the risk assessment process. These approaches, which are collectively referred to as cumulative risk assessment, have potential to be adapted or modified for occupational scenarios and provide a tangible path forward for occupational risk assessment. Accounting for complex exposures in the workplace and the broader risks faced by the individual also requires a more complete consideration of the composite effects of occupational and non-occupational risk factors to fully assess and manage worker health problems. Barriers to integrating these different factors remain, but new and ongoing community-based and worker health-related initiatives may provide mechanisms for identifying and integrating risk from aggregate exposures and cumulative risks from all relevant sources, be they occupational or non-occupational. PMID:26583907

  12. Electromagnetic field exposure assessment in Europe radiofrequency fields (10 MHz-6 GHz).

    PubMed

    Gajšek, Peter; Ravazzani, Paolo; Wiart, Joe; Grellier, James; Samaras, Theodoros; Thuróczy, György

    2015-01-01

    Average levels of exposure to radiofrequency (RF) electromagnetic fields (EMFs) of the general public in Europe are difficult to summarize, as exposure levels have been reported differently in those studies in which they have been measured, and a large proportion of reported measurements were very low, sometimes falling below detection limits of the equipment used. The goal of this paper is to present an overview of the scientific literature on RF EMF exposure in Europe and to characterize exposure within the European population. A comparative analysis of the results of spot or long-term RF EMF measurements in the EU indicated that mean electric field strengths were between 0.08 V/m and 1.8 V/m. The overwhelming majority of measured mean electric field strengths were <1 V/m. It is estimated that <1% were above 6 V/m and <0.1% were above 20 V/m. No exposure levels exceeding European Council recommendations were identified in these surveys. Most population exposures from signals of radio and television broadcast towers were observed to be weak because these transmitters are usually far away from exposed individuals and are spatially sparsely distributed. On the other hand, the contribution made to RF exposure from wireless telecommunications technology is continuously increasing and its contribution was above 60% of the total exposure. According to the European exposure assessment studies identified, three population exposure categories (intermittent variable partial body exposure, intermittent variable low-level whole-body (WB) exposure and continuous low-level WB exposure) were recognized by the authors as informative for possible future risk assessment.

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

    PubMed

    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.

  14. Release of nanomaterials from solid nanocomposites and consumer exposure assessment - a forward-looking review.

    PubMed

    Mackevica, Aiga; Foss Hansen, Steffen

    2016-08-01

    The European chemical legislation requires manufacturers and importers of chemicals to do consumer exposure assessment when the chemical has certain hazards associated to it (e.g. explosive, carcinogenicity, and hazardous to the aquatic environment), but the question is how this obligation can be met in light of the scientific uncertainty and technical challenges related to exposure assessment of nanomaterials. In this paper, we investigate to what extent the information and data in the literature can be used to perform consumer exposure assessment according to the REACH requirements and we identify and discuss the key data needs and provide recommendations for consumer exposure assessment of nanomaterials. In total, we identified 76 studies of relevance. Most studies have analyzed the release of Ag and TiO2 from textiles and paints, and CNT and SiO2 from nanocomposites. Less than half of the studies report their findings in a format that can be used for exposure assessment under REACH, and most do not include characterization of the released particles. Although inhalation, dermal, and oral exposures can be derived using the guidelines on how to complete consumer exposure assessments under REACH, it is clear that the equations are not developed to take the unique properties of nanomaterials into consideration. Future research is therefore needed on developing more generalized methods for representing nanomaterial release from different product groups at relevant environmental conditions. This includes improving the analytical methods for determining nanomaterial alteration and transformation, as well as quantification, which could subsequently lead to more nano-specific consumer exposure assessment models.

  15. A model to assess personal exposure to ELF magnetic fields from common household sources

    SciTech Connect

    Delpizzo, V. )

    1990-01-01

    Emission data are inadequate to characterize the contribution of a source to the total personal extremely-low-frequency (ELF) magnetic field exposure. In this paper, a simple model is proposed that takes into consideration the position of the subject with respect to the source and the duration of exposure. The magnetic field is spatially averaged over the whole body of the exposed subject and integrated over time. Exposure is regarded as significant if it approaches or exceeds 400 microT-h/year. By use of this method, the ELF magnetic fields generated by several household sources were compared with the levels of residential external sources, to assess their relative significance. Some common domestic electrical appliances are found to be responsible for an exposure comparable to that from power lines. When the model is used to assess exposure to electric blankets, apparently conflicting findings may be reconciled.

  16. MODELING POPULATION EXPOSURES TO OUTDOOR SOURCES OF HAZARDOUS AIR POLLUTANTS

    EPA Science Inventory

    Accurate assessment of human exposures is an important part of environmental health effects research. However, most air pollution epidemiology studies rely upon imperfect surrogates of personal exposures, such as information based on available central-site outdoor concentration ...

  17. Assessing exposure to air toxics relative to asthma.

    PubMed Central

    Weisel, Clifford P

    2002-01-01

    Asthma is a respiratory disease whose prevalence has been increasing since the mid 1970s and that affects more than 14.6 million residents of the United States. Environmental triggers of asthma include air pollutants that are respiratory irritants. Air toxics emitted into the ambient air are listed in the 1990 Clean Air Act Amendments as hazardous air pollutants (HAPs) if they can adversely affect human health, including the respiratory tract. HAPs include particulate and gaseous-phase pollutants, individual organic compounds and metals, and mixtures. Associations between asthma exacerbation and both particles and indoor volatile organic compounds (VOCs), often referred to as indoor air quality, have been reported. Studies conducted in the United States, Canada, and Europe over the past two decades have shown that most people living in the developed countries spend the majority of their time indoors and that the air concentrations of many air toxics or HAPs are higher indoors than in the ambient air in urban, suburban, and rural settings. Elevated indoor air concentrations result from emissions of air toxics from consumer products, household furnishings, and personal activities. The Relationship of Indoor, Outdoor and Personal Air (RIOPA) study was designed to oversample homes in close proximity to ambient sources, excluding residences where smokers lived, to determine the contribution of ambient emissions to air toxics exposure. The ratios of indoor to outdoor air concentrations of some VOCs in homes measured during RIOPA were much greater than one, and for most other VOCs that had indoor-to-outdoor ratios close to unity in the majority of homes, elevated ratios were found in the paired samples with the highest concentration. Thus, although ambient emissions contribute to exposure of some air toxics indoors as well as outdoors, this was not true for all of the air toxics and especially for the higher end of exposures to most volatile organic air toxics examined

  18. Ochratoxin A in Portugal: A Review to Assess Human Exposure

    PubMed Central

    Duarte, Sofia C.; Pena, Angelina; Lino, Celeste M.

    2010-01-01

    In Portugal, the climate, dietary habits, and food contamination levels present the characteristics for higher population susceptibility to ochratoxin A (OTA), one of the known mycotoxins with the greatest public health and agro-economic importance. In this review, following a brief historical insight on OTA research, a summary of the available data on OTA occurrence in food (cereals, bread, wine, meat) and biological fluids (blood, urine) is made. With this data, an estimation of intake is made to ascertain and update the risk exposure estimation of the Portuguese population, in comparison to previous studies and other populations. PMID:22069635

  19. Pesticide flow analysis to assess human exposure in greenhouse flower production in Colombia.

    PubMed

    Lesmes-Fabian, Camilo; Binder, Claudia R

    2013-04-01

    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. PMID:23528812

  20. Pesticide flow analysis to assess human exposure in greenhouse flower production in Colombia.

    PubMed

    Lesmes-Fabian, Camilo; Binder, Claudia R

    2013-03-25

    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.

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

    PubMed Central

    Lesmes-Fabian, Camilo; Binder, Claudia R.

    2013-01-01

    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. PMID:23528812

  2. Bisphenol A exposure pathways in early childhood: Reviewing the need for improved risk assessment models.

    PubMed

    Healy, Bridget F; English, Karin R; Jagals, Paul; Sly, Peter D

    2015-01-01

    Bisphenol A (BPA) is a plasticiser found in a number of household plastics, electronics, and food-packaging materials. Over the past 5 years, several human epidemiological studies have reported a positive association between BPA exposure and adverse health outcomes in children, including obesity, asthma, preterm birth, and neuro-behavioural disturbances. These findings are in conflict with international environmental risk assessment models, which predict daily exposure levels to BPA should not pose a risk to child health. The aim of this review is to provide an overview of the evidence for different exposure sources and potential exposure pathways of BPA in early childhood. By collating the findings from experimental models and exposure associations observed in human bio-monitoring studies, we affirm the potential for non-dietary sources to make a substantial contribution to total daily exposure in young children. Infants and toddlers have distinctive exposure sources, physiology, and metabolism of endocrine-disrupting chemicals. We recommend risk-assessment models implement new frameworks, which specifically address exposure and hazard in early childhood. This is particularly important for BPA, which is present in numerous products in the home and day-care environments, and for which animal studies report contradictory findings on its safety at environmentally relevant levels of exposure. PMID:26350983

  3. Exposure assessment of adult intake of bisphenol A (BPA) with emphasis on canned food dietary exposures.

    PubMed

    Lorber, Matthew; Schecter, Arnold; Paepke, Olaf; Shropshire, William; Christensen, Krista; Birnbaum, Linda

    2015-04-01

    Bisphenol A (BPA) is a high-volume, synthetic compound found in epoxy resins and plastics used in food packaging. Food is believed to be a major source of BPA intake. In this study, we measured the concentration of BPA in convenience samplings of foodstuffs purchased in Dallas, Texas. Sampling entailed collection of 204 samples of fresh, frozen, and canned foods in two rounds in 2010. BPA was positive in 73% of the canned food samples, while it was found in only 7% of non-canned foods at low concentrations. The results of this food sampling program were used to calculate adult dietary intakes of BPA. A pathway approach combined food intakes, a "canned fraction" parameter which described what portion of total intake of that food came from canned products, and measured food concentrations. Dietary intakes were calculated as 12.6 ng/kg-day, of which 12.4 ng/kg-day was from canned foods. Canned vegetable intakes alone were 11.9 ng/kg-day. This dietary intake was compared to total intakes of BPA estimated from urine measurements of the National Health and Nutrition Examination Survey (NHANES). Total adult central tendency intakes ranged from 30 to 70 ng/kg-day for NHANES cycles between 2005 and 2010. Three possibilities were explored to explain the difference between these two approaches for intake estimation. Not all foods which may have been canned, particularly canned beverages such as soft drinks, were sampled in our food sampling program. Second, non-food pathways of exposure may be important for adults, including thermal paper exposures, and dust and air exposures. Finally, our canned food concentrations may not be adequately representative of canned foods in the United States; they were found to be generally lower compared to canned food concentrations measured in six other worldwide food surveys including three in North America. Our finding that canned food concentrations greatly exceeded non-canned concentrations was consistent with other studies, and

  4. Exposure assessment of adult intake of bisphenol A (BPA) with emphasis on canned food dietary exposures.

    PubMed

    Lorber, Matthew; Schecter, Arnold; Paepke, Olaf; Shropshire, William; Christensen, Krista; Birnbaum, Linda

    2015-04-01

    Bisphenol A (BPA) is a high-volume, synthetic compound found in epoxy resins and plastics used in food packaging. Food is believed to be a major source of BPA intake. In this study, we measured the concentration of BPA in convenience samplings of foodstuffs purchased in Dallas, Texas. Sampling entailed collection of 204 samples of fresh, frozen, and canned foods in two rounds in 2010. BPA was positive in 73% of the canned food samples, while it was found in only 7% of non-canned foods at low concentrations. The results of this food sampling program were used to calculate adult dietary intakes of BPA. A pathway approach combined food intakes, a "canned fraction" parameter which described what portion of total intake of that food came from canned products, and measured food concentrations. Dietary intakes were calculated as 12.6 ng/kg-day, of which 12.4 ng/kg-day was from canned foods. Canned vegetable intakes alone were 11.9 ng/kg-day. This dietary intake was compared to total intakes of BPA estimated from urine measurements of the National Health and Nutrition Examination Survey (NHANES). Total adult central tendency intakes ranged from 30 to 70 ng/kg-day for NHANES cycles between 2005 and 2010. Three possibilities were explored to explain the difference between these two approaches for intake estimation. Not all foods which may have been canned, particularly canned beverages such as soft drinks, were sampled in our food sampling program. Second, non-food pathways of exposure may be important for adults, including thermal paper exposures, and dust and air exposures. Finally, our canned food concentrations may not be adequately representative of canned foods in the United States; they were found to be generally lower compared to canned food concentrations measured in six other worldwide food surveys including three in North America. Our finding that canned food concentrations greatly exceeded non-canned concentrations was consistent with other studies, and

  5. Exposure assessment of adult intake of bisphenol A (BPA) with emphasis on canned food dietary exposures

    PubMed Central

    Lorber, Matthew; Schecter, Arnold; Paepke, Olaf; Shropshire, William; Christensen, Krista; Birnbaum, Linda

    2015-01-01

    Bisphenol A (BPA) is a high-volume, synthetic compound found in epoxy resins and plastics used in food packaging. Food is believed to be a major source of BPA intake. In this study, we measured the concentration of BPA in convenience samplings of foodstuffs purchased in Dallas, Texas. Sampling entailed collection of 204 samples of fresh, frozen, and canned foods in two rounds in 2010. BPA was positive in 73% of the canned food samples, while it was found in only 7% of non-canned foods at low concentrations. The results of this food sampling program were used to calculate adult dietary intakes of BPA. A pathway approach combined food intakes, a “canned fraction” parameter which described what portion of total intake of that food came from canned products, and measured food concentrations. Dietary intakes were calculated as 12.6 ng/kg-day, of which 12.4 ng/kg-day was from canned foods. Canned vegetable intakes alone were 11.9 ng/kg-day. This dietary intake was compared to total intakes of BPA estimated from urine measurements of the National Health and Nutrition Examination Survey (NHANES). Total adult central tendency intakes ranged from 30 to 70 ng/kg-day for NHANES cycles between 2005 and 2010. Three possibilities were explored to explain the difference between these two approaches for intake estimation. Not all foods which may have been canned, particularly canned beverages such as soft drinks, were sampled in our food sampling program. Second, non-food pathways of exposure may be important for adults, including thermal paper exposures, and dust and air exposures. Finally, our canned food concentrations may not be adequately representative of canned foods in the United States; they were found to be generally lower compared to canned food concentrations measured in six other worldwide food surveys including three in North America. Our finding that canned food concentrations greatly exceeded non-canned concentrations was consistent with other studies, and

  6. Tools to Assess Community-Based Cumulative Risk and Exposures

    EPA Science Inventory

    Multiple agents and stressors can interact in a given community to adversely affect human and ecological conditions. A cumulative risk assessment (CRA) analyzes, characterizes, and potentially quantifies the effects from multiple stressors, which include chemical agents (for exam...

  7. Assessment of mercury exposure among small-scale gold miners using mercury stable isotopes

    SciTech Connect

    Sherman, Laura S.; Blum, Joel D.; Basu, Niladri; Rajaee, Mozhgon; Evers, David C.; Buck, David G.; Petrlik, Jindrich; DiGangi, Joseph

    2015-02-15

    Total mercury (Hg) concentrations in hair and urine are often used as biomarkers of exposure to fish-derived methylmercury (MeHg) and gaseous elemental Hg, respectively. We used Hg stable isotopes to assess the validity of these biomarkers among small-scale gold mining populations in Ghana and Indonesia. Urine from Ghanaian miners displayed similar Δ{sup 199}Hg values to Hg derived from ore deposits (mean urine Δ{sup 199}Hg=0.01‰, n=6). This suggests that urine total Hg concentrations accurately reflect exposure to inorganic Hg among this population. Hair samples from Ghanaian miners displayed low positive Δ{sup 199}Hg values (0.23–0.55‰, n=6) and low percentages of total Hg as MeHg (7.6–29%, n=7). These data suggest that the majority of the Hg in these miners' hair samples is exogenously adsorbed inorganic Hg and not fish-derived MeHg. Hair samples from Indonesian gold miners who eat fish daily displayed a wider range of positive Δ{sup 199}Hg values (0.21–1.32‰, n=5) and percentages of total Hg as MeHg (32–72%, n=4). This suggests that total Hg in the hair samples from Indonesian gold miners is likely a mixture of ingested fish MeHg and exogenously adsorbed inorganic Hg. Based on data from both populations, we suggest that total Hg concentrations in hair samples from small-scale gold miners likely overestimate exposure to MeHg from fish consumption. - Highlights: • Mercury isotopes were measured in hair and urine from small-scale gold miners. • Mercury isotopes indicate that Hg in urine comes from mining activity. • Mercury isotopes suggest Hg in hair is a mixture of fish MeHg and inorganic Hg. • A large percentage of Hg in miner’s hair is released during amalgam burning and adsorbed.

  8. Assessment of general public exposure to LTE and RF sources present in an urban environment.

    PubMed

    Joseph, Wout; Verloock, Leen; Goeminne, Francis; Vermeeren, Günter; Martens, Luc

    2010-10-01

    For the first time, in situ electromagnetic field exposure of the general public to fields from long term evolution (LTE) cellular base stations is assessed. Exposure contributions due to different radiofrequency (RF) sources are compared with LTE exposure at 30 locations in Stockholm, Sweden. Total exposures (0.2-2.6 V/m) satisfy the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels (from 28 V/m for frequency modulation (FM), up to 61 V/m for LTE) at all locations. LTE exposure levels up to 0.8 V/m were measured, and the average contribution of the LTE signal to the total RF exposure equals 4%.

  9. Environmental exposure assessment in European birth cohorts: results from the ENRIECO project.

    PubMed

    Gehring, Ulrike; Casas, Maribel; Brunekreef, Bert; Bergström, Anna; Bonde, Jens Peter; Botton, Jérémie; Chévrier, Cecile; Cordier, Sylvaine; Heinrich, Joachim; Hohmann, Cynthia; Keil, Thomas; Sunyer, Jordi; Tischer, Christina G; Toft, Gunnar; Wickman, Magnus; Vrijheid, Martine; Nieuwenhuijsen, Mark

    2013-01-23

    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 for a specific research

  10. Exposure and inhalation risk assessment in an aluminium cast-house.

    PubMed

    Godderis, L; Vanderheyden, W; Van Geel, J; Moens, G; Masschelein, R; Veulemans, H

    2005-12-01

    To date the exposure, absorption and respiratory health effects of cast-house workers have not been described since most studies performed in the aluminium industry are focused on exposure and health effects of potroom personnel. In the present study, we assessed the external exposure and the absorbed dose of metals in personnel from the aluminium cast house. This was combined with an evaluation of respiratory complaints and the lung function of the personnel. 30 workers from an aluminium casting plant participated and 17 individuals of the packaging and distribution departments were selected as controls. The exposure was assessed by the quantification of total inhalable fume with metal fraction and by the determination of urinary aluminium, chromium, beryllium, manganese and lead concentration. Carbon monoxide (CO), carbon dioxide (CO2), aldehydes and polyaromatic hydrocarbons and man-made mineral fibres concentration were assessed as well. In order to evaluate their respiratory status each participant filled out a questionnaire and their lung function was tested by forced spirometry. Total inhalable fume exposure was maximum 4.37 mg m(-3). Exposure to the combustion gases, man-made mineral fibres and metal fume was well below the exposure limits. Beryllium could not be detected in the urine. The values of aluminium, manganese and lead in the urine were all under the respective reference value. One individual had a urinary chromium excretion above the ACGIH defined biological exposure index (BEI) of 30 microg g(-1) creatinine. There was no significant difference in any of the categories of the respiratory questionnaire and in the results of the spirometry between cast house personnel and referents (Chi-square, all p > 0.05). Exposure in cast houses seem to be acceptable under these conditions. However, peak exposure to fumes cannot be excluded and the potential risk of chromium and beryllium exposure due to the recycling of aluminium requires further attention

  11. Exposure and inhalation risk assessment in an aluminium cast-house.

    PubMed

    Godderis, L; Vanderheyden, W; Van Geel, J; Moens, G; Masschelein, R; Veulemans, H

    2005-12-01

    To date the exposure, absorption and respiratory health effects of cast-house workers have not been described since most studies performed in the aluminium industry are focused on exposure and health effects of potroom personnel. In the present study, we assessed the external exposure and the absorbed dose of metals in personnel from the aluminium cast house. This was combined with an evaluation of respiratory complaints and the lung function of the personnel. 30 workers from an aluminium casting plant participated and 17 individuals of the packaging and distribution departments were selected as controls. The exposure was assessed by the quantification of total inhalable fume with metal fraction and by the determination of urinary aluminium, chromium, beryllium, manganese and lead concentration. Carbon monoxide (CO), carbon dioxide (CO2), aldehydes and polyaromatic hydrocarbons and man-made mineral fibres concentration were assessed as well. In order to evaluate their respiratory status each participant filled out a questionnaire and their lung function was tested by forced spirometry. Total inhalable fume exposure was maximum 4.37 mg m(-3). Exposure to the combustion gases, man-made mineral fibres and metal fume was well below the exposure limits. Beryllium could not be detected in the urine. The values of aluminium, manganese and lead in the urine were all under the respective reference value. One individual had a urinary chromium excretion above the ACGIH defined biological exposure index (BEI) of 30 microg g(-1) creatinine. There was no significant difference in any of the categories of the respiratory questionnaire and in the results of the spirometry between cast house personnel and referents (Chi-square, all p > 0.05). Exposure in cast houses seem to be acceptable under these conditions. However, peak exposure to fumes cannot be excluded and the potential risk of chromium and beryllium exposure due to the recycling of aluminium requires further attention.

  12. Exposure assessment for trihalomethanes in municipal drinking water and risk reduction strategy.

    PubMed

    Chowdhury, Shakhawat

    2013-10-01

    Lifetime exposure to disinfection byproducts (DBPs) in municipal water may pose risks to human health. Current approaches of exposure assessments use DBPs in cold water during showering, while warming of chlorinated water during showering may increase trihalomethane (THM) formation in the presence of free residual chlorine. Further, DBP exposure through dermal contact during showering is estimated using steady-state condition between the DBPs in shower water impacting on human skin and skin exposed to shower water. The lag times to achieve steady-state condition between DBPs in shower water and human skin can vary in the range of 9.8-391.2 min, while shower duration is often less than the lag times. Assessment of exposure without incorporating these factors might have misinterpreted DBP exposure in some previous studies. In this study, exposure to THMs through ingestion was estimated using cold water THMs, while THM exposure through inhalation and dermal contact during showering was estimated using THMs in warm water. Inhalation of THMs was estimated using THM partition into the shower air, while dermal uptake was estimated by incorporating lag times (e.g., unsteady and steady-state phases of exposure) during showering. Probabilistic approach was followed to incorporate uncertainty in the assessment. Inhalation and dermal contact during showering contributed 25-60% of total exposure. Exposure to THMs during showering can be controlled by varying shower stall volume, shower duration and air exchange rate following power law equations. The findings might be useful in understanding exposure to THMs, which can be extended to other volatile compounds in municipal water.

  13. Environmental exposure assessment in European birth cohorts: results from the ENRIECO project

    PubMed Central

    2013-01-01

    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 for a specific research

  14. Safety assessment of chronic oral exposure to iron oxide nanoparticles

    NASA Astrophysics Data System (ADS)

    Chamorro, Susana; Gutiérrez, Lucía; Vaquero, María Pilar; Verdoy, Dolores; Salas, Gorka; Luengo, Yurena; Brenes, Agustín; José Teran, Francisco

    2015-05-01

    Iron oxide nanoparticles with engineered physical and biochemical properties are finding a rapidly increasing number of biomedical applications. However, a wide variety of safety concerns, especially those related to oral exposure, still need to be addressed for iron oxide nanoparticles in order to reach clinical practice. Here, we report on the effects of chronic oral exposure to low doses of γ-Fe2O3 nanoparticles in growing chickens. Animal observation, weight, and diet intake reveal no adverse signs, symptoms, or mortality. No nanoparticle accumulation was observed in liver, spleen, and duodenum, with feces as the main excretion route. Liver iron level and duodenal villi morphology reflect the bioavailability of the iron released from the partial transformation of γ-Fe2O3 nanoparticles in the acid gastric environment. Duodenal gene expression studies related to the absorption of iron from γ-Fe2O3 nanoparticles indicate the enhancement of a ferric over ferrous pathway supporting the role of mucins. Our findings reveal that oral administration of iron oxide nanoparticles is a safe route for drug delivery at low nanoparticle doses.

  15. Exposure-driven risk assessment: applying exposure-based waiving of toxicity tests under REACH.

    PubMed

    Rowbotham, Anna L; Gibson, Rosemary M

    2011-08-01

    The REACH Regulation 1907/2006/EC aims to improve knowledge of the potential risks to humans and the environment of the large number of chemicals produced and used in the EU. The testing requirements are likely to trigger numerous toxicological studies, potentially involving millions of experimental animals, despite the professed goal of REACH to reduce vertebrate testing. It may be necessary therefore to shift emphasis away from animal studies towards more pragmatic strategies, reserving animal tests for the substances of greatest concern. One approach is to waive certain tests based on levels of exposure to the substance. This review explores application of 'Exposure-Based Waiving' (EBW) of toxicity studies, with a particular focus on inhalation where possible, considering the potential qualitative and quantitative supporting arguments that might be made, including the use of thresholds of toxicological concern. Incorporating EBW into intelligent testing strategies for substance registration could advance the goals of REACH and the 3Rs (reduction, replacement and refinement of animals in research) by reducing the usage of animals in toxicity tests, whilst maintaining appropriate protection of human health and the environment. However greater regulatory evaluation, acceptance and guidance are required for EBW to achieve its full impact.

  16. Combining a Job-Exposure Matrix with Exposure Measurements to Assess Occupational Exposure to Benzene in a Population Cohort in Shanghai, China

    PubMed Central

    Friesen, Melissa C.; Coble, Joseph B.; Lu, Wei; Shu, Xiao-Ou; Ji, Bu-Tian; Xue, Shouzheng; Portengen, Lutzen; Chow, Wong-Ho; Gao, Yu-Tang; Yang, Gong; Rothman, Nathaniel; Vermeulen, Roel

    2012-01-01

    Background: Generic job-exposure matrices (JEMs) are often used in population-based epidemiologic studies to assess occupational risk factors when only the job and industry information of each subject is available. JEM ratings are often based on professional judgment, are usually ordinal or semi-quantitative, and often do not account for changes in exposure over time. We present an empirical Bayesian framework that combines ordinal subjective JEM ratings with benzene measurements. Our aim was to better discriminate between job, industry, and time differences in exposure levels compared to using a JEM alone. Methods: We combined 63 221 short-term area air measurements of benzene exposure (1954–2000) collected during routine health and safety inspections in Shanghai, China, with independently developed JEM intensity ratings for each job and industry using a mixed-effects model. The fixed-effects terms included the JEM intensity ratings for job and industry (both ordinal, 0–3) and a time trend that we incorporated as a b-spline. The random-effects terms included job (n = 33) and industry nested within job (n = 399). We predicted the benzene concentration in two ways: (i) a calibrated JEM estimate was calculated using the fixed-effects model parameters for calendar year and JEM intensity ratings; (ii) a job-/industry-specific estimate was calculated using the fixed-effects model parameters and the best linear unbiased predictors from the random effects for job and industry using an empirical Bayes estimation procedure. Finally, we applied the predicted benzene exposures to a prospective population-based cohort of women in Shanghai, China (n = 74 942). Results: Exposure levels were 13 times higher in 1965 than in 2000 and declined at a rate that varied from 4 to 15% per year from 1965 to 1985, followed by a small peak in the mid-1990s. The job-/industry-specific estimates had greater differences between exposure levels than the calibrated JEM estimates (97.5th

  17. A retrospective cohort study among iron-steel workers in Anshan, China: exposure assessment.

    PubMed

    Hoshuyama, Tsutomu; Pan, Guowei; Tanaka, Chieko; Feng, Yiping; Yu, Lianzheng; Liu, Tiefu; Liu, Liming; Hanaoka, Tomoyuki; Takahashi, Ken

    2006-09-01

    Although adequate assessment of exposure is needed in epidemiological studies among foundry workers, previous studies are often lacking in this aspect. We conducted a retrospective cohort study of a Chinese iron and steel company with a 14-yr follow up during 1980-1993. Exposure assessment was performed for a single job, i.e., the current job for the active worker and the longest job for the retired or deceased worker as of the end of the follow-up, which was allocated as the surrogate of lifetime job and was applied to a job-exposure matrix. Of the 147,062 cohort members, 52,394 males (43%) and 5,291 females (21%) were exposed to any of 15 hazardous factors such as dust, silica, PAHs (polycyclic aromatic hydrocarbons), CO (carbon monoxide) and heat. In 2,104 randomly selected samples, the exposure assessment of exposed workers based on a single job was found to be 12-14% lower than the real situation. This study suggests that the exposure assessment is valuable in evaluating the health effects among the foundry workers, despite some limitations such as underestimation of exposure assessment and the lack of data regarding smoking and drinking habits. PMID:16981402

  18. Aggregate versus Individual-Level Sexual Behavior Assessment: How Much Detail Is Needed to Accurately Estimate HIV/STI Risk?

    ERIC Educational Resources Information Center

    Pinkerton, Steven D.; Galletly, Carol L.; McAuliffe, Timothy L.; DiFranceisco, Wayne; Raymond, H. Fisher; Chesson, Harrell W.

    2010-01-01

    The sexual behaviors of HIV/sexually transmitted infection (STI) prevention intervention participants can be assessed on a partner-by-partner basis: in aggregate (i.e., total numbers of sex acts, collapsed across partners) or using a combination of these two methods (e.g., assessing five partners in detail and any remaining partners in aggregate).…

  19. Exposure assessment of dietary cadmium: findings from shanghainese over 40 years, China

    PubMed Central

    2013-01-01

    Background Environmental exposure to cadmium causes renal dysfunction and bone damage. Cadmium contamination in food is regarded as the main environmental source of non-occupational exposure. The aim of this study was to assess the contribution of dietary cadmium exposure in environmental cadmium exposure and its health risk among adults in Shanghai, China. Methods A cross-sectional survey about food consumption was conducted in 2008 among 207 citizens aged over 40 years in Shanghai, China. The food frequency questionnaire was combined with food, tobacco and water cadmium exposure to estimate the daily environmental cadmium exposure in both point and probabilistic estimations. Urine and blood samples of the participants were analyzed for internal exposure to total cadmium. Correlation analysis was conducted between the internal cadmium exposure and environmental cadmium exposure. Results According to the point estimation, average daily environmental cadmium exposure of the participants was 16.7 μg/day and approached 33.8% of the provisional tolerable daily intake (PTDI). Dietary and tobacco cadmium exposure approached 25.8% and 7.9% of the PTDI, respectively. Males had higher levels of dietary cadmium exposure than females (p?=?0.002). The probabilistic model showed that 93.4% of the population did not have any health risks from dietary cadmium exposure. By sensitivity analysis, tobacco consumption, tobacco cadmium level, cadmium in vegetables and cadmium in rice accounted for 27.5%, 24.9%, 20.2% and 14.6% of the total cadmium exposure, respectively. The mean values of urinary and blood cadmium among the study population were 0.5 μg/L and 1.9 μg/L, respectively. Positive correlations were observed between environmental cadmium exposure and blood cadmium (R?=?0.52, P<0.01), tobacco cadmium intake and blood cadmium excluding non-smokers (R?=?0.26, P?=?0.049<0.05), and urine cadmium and age (R?=?0.15, P?=?0.037). Conclusions It has been suggested that there is no

  20. Exposure as Part of a Systems Approach for Assessing Risk

    EPA Science Inventory

    The U.S. Environmental Protection Agency is facing large challenges in managing environmental chemicals with increasingly complex requirements for assessing risk that push the limits of our current approaches. To address some of these challenges, the National Research Council (NR...

  1. Incorporating exposure science into life-cycle assessment

    EPA Science Inventory

    Life-cycle assessment (LCA) is used to estimate the potential for environmental damage that may be caused by a product or process, ideally before the product or process begins. LCA includes all of the steps from extracting natural resources through manufacturing through product u...

  2. Inhalable dust measurements as a first approach to assessing occupational exposure in the pharmaceutical industry.

    PubMed

    Champmartin, C; Clerc, F

    2014-01-01

    Occupational exposure to active ingredients in the pharmaceutical industry has been the subject of very few published studies. Nevertheless, operations involving active powdered drugs or dusty operations potentially lead to operator exposure. The aim of this study was to collect occupational exposure data in the pharmaceutical industry for production processes involving powdered active ingredients. While the possibility of assessing drug exposure from dust level is examined, this article focuses on inhalable dust exposure, without taking chemical risk into account. A total of 377 atmospheric (ambient and personal) samples were collected in nine drug production sites (pharmaceutical companies and contract manufacturing organizations) and the dust levels were assessed. For each sample, relevant contextual information was collected. A wide range of results was observed, both site- and operation-dependent. Exposure to inhalable dust levels varied from 0.01 mg/m(3)to 135 mg/m(3). Though restricted to dust exposure, the study highlighted some potentially critical situations or operations, in particular manual tasks (loading, unloading, mechanical actions) performed in open systems. Simple preventive measures such as ventilation, containment, and minimization of manual handling should reduce dust emissions and workers' exposure to inhalable dust.

  3. Exposure assessment for a large epidemiological study of aircraft manufacturing workers.

    PubMed

    Marano, D E; Boice, J D; Fryzek, J P; Morrison, J A; Sadler, C J; McLaughlin, J K

    2000-08-01

    Methods were developed to assess exposure to a wide variety of chemicals for nearly 80,000 workers involved in manufacturing aircraft since 1928. The facilities, now closed, consisted of four major plants, over 200 buildings, and a changing workforce during 60 years of operation. To access chemical exposures by specific jobs and calendar years, we reviewed complete work histories, examined detailed job descriptions available going back to 1940, interviewed long-term employees, conducted walk-through visits of aircraft manufacturing plants, reviewed comprehensive environmental assessment reports and industrial hygiene surveys on the facilities, and built on experience gained in previous studies of the aircraft industry. Using computer-based imaging systems, we examined and evaluated the complete work histories found on service record cards for the cohort and abstracted detailed information on all jobs held among the factory workers who had been employed for at least one year. Jobs were classified into one of three exposure categories related to the use of specific chemicals: routine, intermittent, and none, and these classifications were subsequently used in the epidemiological analyses. The approach to exposure assessment began with the most general categorization of employees (i.e., all workers) and then became progressively more specific, that is, factor workers, job families (similar activities), job titles, and jobs with chemical usage (exposure potential). Because exposure surveys were limited or absent during the early years of plant operations, we did not assign quantitative measures of exposure to individual job activities. Instead, we used as our exposure metric, the length of time spent in jobs with potential exposure to the chemical. Important occupational exposures included chromate-containing compounds such as used in paint primers, trichloroethylene and perchloroethylene used as vapor-state degreasing solvents, and a broad range of other solvents.

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

    NASA Astrophysics Data System (ADS)

    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.

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

    NASA Astrophysics Data System (ADS)

    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.

  6. Harmonisation of food categorisation systems for dietary exposure assessments among European children.

    PubMed

    De Neve, M; Sioen, I; Boon, P E; Arganini, C; Moschandreas, J; Ruprich, J; Lafay, L; Amiano, P; Arcella, D; Azpiri, M; Busk, L; Christensen, T; D'addezio, L; Fabiansson, S; Hilbig, A; Hirvonen, T; Kersting, M; Koulouridaki, S; Liukkonen, K-H; Oltarzewski, M; Papoutsou, S; Rehurkova, I; Ribas-Barba, L; Serra-Majem, L; Tornaritis, M; Trolle, E; Van Klaveren, J D; Verger, E; Walkiewicz, A; Westerlund, A; De Henauw, S; Huybrechts, I

    2010-12-01

    Within the European project called EXPOCHI (Individual Food Consumption Data and Exposure Assessment Studies for Children), 14 different European individual food consumption databases of children were used to conduct harmonised dietary exposure assessments for lead, chromium, selenium and food colours. For this, two food categorisation systems were developed to classify the food consumption data in such a way that these could be linked to occurrence data of the considered compounds. One system served for the exposure calculations of lead, chromium and selenium. The second system was developed for the exposure assessment of food colours. The food categories defined for the lead, chromium and selenium exposure calculations were used as a basis for the food colour categorisation, with adaptations to optimise the linkage with the food colour occurrence data. With this work, an initial impetus was given to make user-friendly food categorisation systems for contaminants and food colours applicable on a pan-European level. However, a set of difficulties were encountered in creating a common food categorisation system for 14 individual food consumption databases that differ in the type and number of foods coded and in level of detail provided about the consumed foods. The work done and the problems encountered in this project can be of interest for future projects in which food consumption data will be collected on a pan-European level and used for common exposure assessments. PMID:21108090

  7. Assessing and reporting uncertainties in dietary exposure analysis: Mapping of uncertainties in a tiered approach.

    PubMed

    Kettler, Susanne; Kennedy, Marc; McNamara, Cronan; Oberdörfer, Regina; O'Mahony, Cian; Schnabel, Jürgen; Smith, Benjamin; Sprong, Corinne; Faludi, Roland; Tennant, David

    2015-08-01

    Uncertainty analysis is an important component of dietary exposure assessments in order to understand correctly the strength and limits of its results. Often, standard screening procedures are applied in a first step which results in conservative estimates. If through those screening procedures a potential exceedance of health-based guidance values is indicated, within the tiered approach more refined models are applied. However, the sources and types of uncertainties in deterministic and probabilistic models can vary or differ. A key objective of this work has been the mapping of different sources and types of uncertainties to better understand how to best use uncertainty analysis to generate more realistic comprehension of dietary exposure. In dietary exposure assessments, uncertainties can be introduced by knowledge gaps about the exposure scenario, parameter and the model itself. With this mapping, general and model-independent uncertainties have been identified and described, as well as those which can be introduced and influenced by the specific model during the tiered approach. This analysis identifies that there are general uncertainties common to point estimates (screening or deterministic methods) and probabilistic exposure assessment methods. To provide further clarity, general sources of uncertainty affecting many dietary exposure assessments should be separated from model-specific uncertainties. PMID:25890086

  8. Categorization framework to aid exposure assessment of nanomaterials in consumer products.

    PubMed

    Hansen, Steffen Foss; Michelson, Evan S; Kamper, Anja; Borling, Pernille; Stuer-Lauridsen, Frank; Baun, Anders

    2008-07-01

    Exposure assessment is crucial for risk assessment for nanomaterials. We propose a framework to aid exposure assessment in consumer products. We determined the location of the nanomaterials and the chemical identify of the 580 products listed in the inventory maintained by the Woodrow Wilson International Center for Scholars, of which 37% used nanoparticles suspended in liquids, whereas <1% contained "free airborne nanoparticles". C(60) is currently only used as suspended nanoparticles in liquids and nanosilver is used more as surface bound nanoparticles than as particles suspended in liquids. Based on the location of the nanostructure we were able to further group the products into categories of: (1) expected, (2) possible, and (3) no expected exposure. Most products fall into the category of expected exposure, but we were not able to complete a quantitative exposure assessment mainly due to the lack of information on the concentration of the nanomaterial in the products--a problem that regulators and industry will have to address if we are to have realistic exposure assessment in the future. To illustrate the workability of our procedure, we applied it to four product scenarios using the best estimates available and/or worst-case assumptions. Using the best estimates available and/or worst-case assumptions we estimated the consumer exposure to be 26, 15, and 44 microg kg(-1) bw year(-1) for a facial lotion, a fluid product, and a spray product containing nanoparticles, respectively. The application of sun lotion containing 2% nanoparticles result in an exposure of 56.7 mg kg(-1) bw d(-1) for a 2-year-old child, if the amounts applied correspond to the European Commission recommendations on use of sunscreen.

  9. Aflatoxins in hazelnuts and dried figs: Occurrence and exposure assessment.

    PubMed

    Kabak, Bulent