Evaluation of employee exposure to organic tin compounds used as stabilizers at PVC processing facilities.

PubMed

Boraiko, Carol; Batt, John

2005-02-01

Organic tin compounds are primary substances used as heat stabilizers by the polyvinyl chloride (PVC) industry. The use of these compounds in the PVC industry is generally well controlled, usually by automated processes. This study was conducted to provide an overview of worker exposure to organic tin compounds at PVC processing facilities and to verify that these exposures are below the threshold limit value (TLV((R))) set by the American Conference of Governmental Industrial Hygienists for organic tin. The basis of the TLV indicates the principal concern is to minimize adverse effects on immune function and the central nervous system from airborne exposure to organic tin. The TLV has a skin designation based on the potential for percutaneous absorption; the TLVs for inhalation exposures are based on the presumption that there is no concurrent exposure via the skin and oral ingestion routes. Personal exposure monitoring was conducted following the National Institute for Occupational Safety and Health (NIOSH) 5504 sampling method and a modified version of the NIOSH analytical method. The results were reported as"total tin."The data indicated no average exposure levels for individual tasks exceeded the organic tin TLV, and 96%of results the samples were less than 20%of the TLV. Only 1 sample of 102 exceeded the TLV, and the individual was wearing appropriate respiratory protection. Subsequent investigation indicated the highest exposures occurred while the operators were conducting tasks that included manual handling of the organic tin compounds. These data suggest manual operations may have a greater potential for organic tin exposure.

Who Is Worst Off? Developing a Severity-scoring Model of Complex Emergency Affected Countries in Order to Ensure Needs Based Funding.

PubMed

Eriksson, Anneli; Ohlsén, Ylva Kristina; Garfield, Richard; von Schreeb, Johan

2015-11-03

Disasters affect close to 400 million people each year. Complex Emergencies (CE) are a category of disaster that affects nearly half of the 400 million and often last for several years. To support the people affected by CE, humanitarian assistance is provided with the aim of saving lives and alleviating suffering. It is widely agreed that funding for this assistance should be needs-based. However, to date, there is no model or set of indicators that quantify and compare needs from one CE to another. In an effort to support needs-based and transparent funding of humanitarian assistance, the aim of this study is to develop a model that distinguishes between levels of severity among countries affected by CE. In this study, severity serves as a predictor for level of need. The study focuses on two components of severity: vulnerability and exposure. In a literature and Internet search we identified indicators that characterize vulnerability and exposure to CE. Among the more than 100 indicators identified, a core set of six was selected in an expert ratings exercise. Selection was made based on indicator availability and their ability to characterize preexisting or underlying vulnerabilities (four indicators) or to quantify exposure to a CE (two indicators). CE from 50 countries were then scored using a 3-tiered score (Low-Moderate, High, Critical).  The developed model builds on the logic of the Utstein template. It scores severity based on the readily available value of four vulnerability and four exposure indicators. These are 1) GNI per capita, PPP, 2) Under-five mortality rate, per 1 000 live births, 3) Adult literacy rate, % of people ages 15 and above, 4) Underweight, % of population under 5 years, and 5) number of persons and proportion of population affected, and 6) number of uprooted persons and proportion of population uprooted. The model can be used to derive support for transparent, needs-based funding of humanitarian assistance. Further research is needed to determine its validity, the robustness of indicators and to what extent levels of scoring relate to CE outcome.

Tracking contributions to human body burden of environmental chemicals by correlating environmental measurements with biomarkers.

PubMed

Shin, Hyeong-Moo; McKone, Thomas E; Sohn, Michael D; Bennett, Deborah H

2014-01-01

The work addresses current knowledge gaps regarding causes for correlations between environmental and biomarker measurements and explores the underappreciated role of variability in disaggregating exposure attributes that contribute to biomarker levels. Our simulation-based study considers variability in environmental and food measurements, the relative contribution of various exposure sources (indoors and food), and the biological half-life of a compound, on the resulting correlations between biomarker and environmental measurements. For two hypothetical compounds whose half-lives are on the order of days for one and years for the other, we generate synthetic daily environmental concentrations and food exposures with different day-to-day and population variability as well as different amounts of home- and food-based exposure. Assuming that the total intake results only from home-based exposure and food ingestion, we estimate time-dependent biomarker concentrations using a one-compartment pharmacokinetic model. Box plots of modeled R2 values indicate that although the R2 correlation between wipe and biological (e.g., serum) measurements is within the same range for the two compounds, the relative contribution of the home exposure to the total exposure could differ by up to 20%, thus providing the relative indication of their contribution to body burden. The novel method introduced in this paper provides insights for evaluating scenarios or experiments where sample, exposure, and compound variability must be weighed in order to interpret associations between exposure data.

Skin exposure to aliphatic polyisocyanates in the auto body repair and refinishing industry: III. A personal exposure algorithm.

PubMed

Liu, Youcheng; Stowe, Meredith H; Bello, Dhimiter; Sparer, Judy; Gore, Rebecca J; Cullen, Mark R; Redlich, Carrie A; Woskie, Susan R

2009-01-01

Isocyanate skin exposure may play an important role in sensitization and the development of isocyanate asthma, but such exposures are frequently intermittent and difficult to assess. Exposure metrics are needed to better estimate isocyanate skin exposures. The goal of this study was to develop a semiquantitative algorithm to estimate personal skin exposures in auto body shop workers using task-based skin exposure data and daily work diaries. The relationship between skin and respiratory exposure metrics was also evaluated. The development and results of respiratory exposure metrics were previously reported. Using the task-based data obtained with a colorimetric skin exposure indicator and a daily work diary, we developed a skin exposure algorithm to estimate a skin exposure index (SEI) for each worker. This algorithm considered the type of personal protective equipment (PPE) used, the percentage of skin area covered by PPE and skin exposures without and underneath the PPE. The SEI was summed across the day (daily SEI) and survey week (weekly average SEI) for each worker, compared among the job title categories and also compared with the respiratory exposure metrics. A total of 893 person-days was calculated for 232 workers (49 painters, 118 technicians and 65 office workers) from 33 auto body shops. The median (10th-90th percentile, maximum) daily SEI was 0 (0-0, 1.0), 0 (0-1.9, 4.8) and 1.6 (0-3.5, 6.1) and weekly average SEI was 0 (0-0.0, 0.7), 0.3 (0-1.6, 4.2) and 1.9 (0.4-3.0, 3.6) for office workers, technicians and painters, respectively, which were significantly different (P < 0.0001). The median (10th-90th percentile, maximum) daily SEI was 0 (0-2.4, 6.1) and weekly average SEI was 0.2 (0-2.3, 4.2) for all workers. A relatively weak positive Spearman correlation was found between daily SEI and time-weighted average (TWA) respiratory exposure metrics (microg NCO m(-3)) (r = 0.380, n = 893, P < 0.0001) and between weekly SEI and TWA respiratory exposure metrics (r = 0.482, n = 232, P < 0.0001). The skin exposure algorithm developed in this study provides task-based personal daily and weekly average skin exposure indices that are adjusted for the use of PPE. These skin exposure indices can be used to assess isocyanate exposure-response relationships.

Whole-Body Lifetime Occupational Lead Exposure and Risk of Parkinson’s Disease

DOE Office of Scientific and Technical Information (OSTI.GOV)

Coon , Steven; Stark, Azadeh; Peterson, Edward

2006-12-01

We enrolled 121 PD patients and 414 age-, sex-, and race-, frequency-matched controls in a case–control study. As an indicator of chronic Pb exposure, we measured concentrations of tibial and calcaneal bone Pb stores using 109Cadmium excited K-series X-ray fluorescence. As an indicator of recent exposure, we measured blood Pb concentration. We collected occupational data on participants from 18 years of age until the age at enrollment, and an industrial hygienist determined the duration and intensity of environmental Pb exposure. We employed physiologically based pharmacokinetic modeling to combine these data, and we estimated whole-body lifetime Pb exposures for each individual.more » Logistic regression analysis produced estimates of PD risk by quartile of lifetime Pb exposure.« less

Exposure and non-fear emotions: A randomized controlled study of exposure-based and rescripting-based imagery in PTSD treatment.

PubMed

Langkaas, Tomas Formo; Hoffart, Asle; Øktedalen, Tuva; Ulvenes, Pål G; Hembree, Elizabeth A; Smucker, Mervin

2017-10-01

Interventions involving rescripting-based imagery have been proposed as a better approach than exposure-based imagery when posttraumatic stress disorder (PTSD) is associated with emotions other than fear. Prior research led to the study's hypotheses that (a) higher pretreatment non-fear emotions would predict relatively better response to rescripting as compared to exposure, (b) rescripting would be associated with greater reduction in non-fear emotions, and (c) pretreatment non-fear emotions would predict poor response to exposure. A clinically representative sample of 65 patients presenting a wide range of traumas was recruited from patients seeking and being offered PTSD treatment in an inpatient setting. Subjects were randomly assigned to 10 weeks of treatment involving either rescripting-based imagery (Imagery Rescripting; IR) or exposure-based imagery (Prolonged Exposure; PE). Patients were assessed on outcome and emotion measures at pretreatment, posttreatment and 12 months follow-up. Comparison to control benchmarks indicated that both treatments were effective, but no outcome differences between them appeared. None of the initial hypotheses were supported. The results from this study challenge previous observations and hypotheses about exposure mainly being effective for fear-based PTSD and strengthen the notion that exposure-based treatment is a generally effective treatment for all types of PTSD. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Health surveillance of workers with prior exposure to asbestos. Application in the metallurgy/metal mechanical field].

PubMed

Rivolta, G; Della Foglia, M; Donelli, S; Riboldi, L

2006-01-01

To improve the health surveillance program for workers with a known previous exposure to asbestos in a big metallurgic-mechanical industry from Lombardy, the sources of risk and the different exposure levels hare been reconstructed based on specific jobs. The eligibility criteria and a specific work program including information and organization supports hare been established by a work group composed by health physicians, workers and industrial hygienists. The major goals of the program were: to listen and support each worker who perceives worries about his health status; to prevent, if possible, diseases, especially cancer, resulting from exposure; to document the existing injuries for legal compensation. The resulting actions consist of counselling; indication to follow an adequate life and work style; indication, based on specific request of worker, of sanitary checks of first or eventually second level.

Installation Restoration Program. Remedial Investigation Report: Minnesota Air National Guard Base Duluth International Airport, Duluth, Minnesota. Volume 7

DTIC Science & Technology

1990-01-01

Selection of Indicator Chemicals 6-36 6.2.2 Estimation of Exposure Point Concentrations or Emission Rates 6-38 6.2.2.1 Exposure Pathway Analysis 6-38...Exposure Point Concentrations or Emission Rates 6-50 j 6.3.2.1 Exposure Pathway Analysis 6-52 6.3.2.2 Exposure Point Concentrations 6-55 6.3.2.3...Exposure Point Concentrations or Emission Rates 6-62 6.4.2.1 Exposure Pathway Analysis 6-62 6.4.2.2 Exposure Point Concentrations 6-69 6.4.2.3

Mobile phone base stations-Effects on wellbeing and health.

PubMed

Kundi, Michael; Hutter, Hans-Peter

2009-08-01

Studying effects of mobile phone base station signals on health have been discouraged by authoritative bodies like WHO International EMF Project and COST 281. WHO recommended studies around base stations in 2003 but again stated in 2006 that studies on cancer in relation to base station exposure are of low priority. As a result only few investigations of effects of base station exposure on health and wellbeing exist. Cross-sectional investigations of subjective health as a function of distance or measured field strength, despite differences in methods and robustness of study design, found indications for an effect of exposure that is likely independent of concerns and attributions. Experimental studies applying short-term exposure to base station signals gave various results, but there is weak evidence that UMTS and to a lesser degree GSM signals reduce wellbeing in persons that report to be sensitive to such exposures. Two ecological studies of cancer in the vicinity of base stations report both a strong increase of incidence within a radius of 350 and 400m respectively. Due to the limitations inherent in this design no firm conclusions can be drawn, but the results underline the urgent need for a comprehensive investigation of this issue. Animal and in vitro studies are inconclusive to date. An increased incidence of DMBA induced mammary tumors in rats at a SAR of 1.4W/kg in one experiment could not be replicated in a second trial. Indications of oxidative stress after low-level in vivo exposure of rats could not be supported by in vitro studies of human fibroblasts and glioblastoma cells. From available evidence it is impossible to delineate a threshold below which no effect occurs, however, given the fact that studies reporting low exposure were invariably negative it is suggested that power densities around 0.5-1mW/m(2) must be exceeded in order to observe an effect. The meager data base must be extended in the coming years. The difficulties of investigating long-term effects of base station exposure have been exaggerated, considering that base station and handset exposure have almost nothing in common both needs to be studied independently. It cannot be accepted that studying base stations is postponed until there is firm evidence for mobile phones.

Cardiovascular impacts and micro-environmental exposure factors associated with continuous personal PM2.5 monitoring.

PubMed

Hammond, Davyda; Croghan, Carry; Shin, Hwashin; Burnett, Richard; Bard, Robert; Brook, Robert D; Williams, Ron

2014-07-01

The US Environmental Protection Agency's (US EPA) Detroit Exposure and Aerosol Research Study (DEARS) has provided extensive data on human exposures to a wide variety of air pollutants and their impact on human health. Previous analyses in the DEARS revealed select cardiovascular (CV) health outcomes such as increase in heart rate (HR) associated with hourly based continuous personal fine particulate matter (PM2.5) exposures in this adult, non-smoking cohort. Examination of time activity diary (TAD), follow-up questionnaire (FQ) and the continuous PM2.5 personal monitoring data provided the means to more fully examine the impact of discreet human activity patterns on personal PM2.5 exposures and changes in CV outcomes. A total of 329 343 min-based PM2.5 personal measurements involving 50 participants indicated that ∼75% of these total events resulted in exposures <35 μg/m(3). Cooking and car-related events accounted for nearly 10% of the hourly activities that were identified with observed peaks in personal PM2.5 exposures. In-residence cooking often resulted in some of the highest incidents of 1 min exposures (33.5-17.6 μg/m(3)), with average peaks for such events in excess of 209 μg/m(3). PM2.5 exposure data from hourly based personal exposure activities (for example,, cooking, cleaning and household products) were compared with daily CV data from the DEARS subject population. A total of 1300 hourly based lag risk estimates associated with changes in brachial artery diameter and flow-mediated dilatation (BAD and FMD, respectively), among others, were defined for this cohort. Findings indicate that environmental tobacco smoke (ETS) exposures resulted in significant HR changes between 3 and 7 h following the event, and exposure to smells resulted in increases in BAD on the order of 0.2-0.7 mm/μg/m(3). Results demonstrate that personal exposures may be associated with several biological responses, sometimes varying in degree and direction in relation to the extent of the exposure.

Health-based ingestion exposure guidelines for Vibrio cholerae: Technical basis for water reuse applications.

PubMed

Watson, Annetta P; Armstrong, Anthony Q; White, George H; Thran, Brandolyn H

2018-02-01

U.S. military and allied contingency operations are increasingly occurring in locations with limited, unstable or compromised fresh water supplies. Non-potable graywater reuse is currently under assessment as a viable means to increase mission sustainability while significantly reducing the resources, logistics and attack vulnerabilities posed by transport of fresh water. Development of health-based (non-potable) exposure guidelines for the potential microbial components of graywater would provide a logical and consistent human-health basis for water reuse strategies. Such health-based strategies will support not only improved water security for contingency operations, but also sustainable military operations. Dose-response assessment of Vibrio cholerae based on adult human oral exposure data were coupled with operational water exposure scenario parameters common to numerous military activities, and then used to derive health risk-based water concentrations. The microbial risk assessment approach utilized oral human exposure V. cholerae dose studies in open literature. Selected studies focused on gastrointestinal illness associated with experimental infection by specific V. cholerae serogroups most often associated with epidemics and pandemics (O1 and O139). Nonlinear dose-response model analyses estimated V. cholerae effective doses (EDs) aligned with gastrointestinal illness severity categories characterized by diarrheal purge volume. The EDs and water exposure assumptions were used to derive Risk-Based Water Concentrations (CFU/100mL) for mission-critical illness severity levels over a range of water use activities common to military operations. Human dose-response studies, data and analyses indicate that ingestion exposures at the estimated ED 1 (50CFU) are unlikely to be associated with diarrheal illness while ingestion exposures at the lower limit (200CFU) of the estimated ED 10 are not expected to result in a level of diarrheal illness associated with degraded individual capability. The current analysis indicates that the estimated ED 20 (approximately 1000CFU) represents initiation of a more advanced stage of diarrheal illness associated with clinical care. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

Environmental risks in the developing world: exposure indicators for evaluating interventions, programmes, and policies.

PubMed

Ezzati, Majid; Utzinger, Jürg; Cairncross, Sandy; Cohen, Aaron J; Singer, Burton H

2005-01-01

Monitoring and empirical evaluation are essential components of evidence based public health policies and programmes. Consequently, there is a growing interest in monitoring of, and indicators for, major environmental health risks, particularly in the developing world. Current large scale data collection efforts are generally disconnected from micro-scale studies in health sciences, which in turn have insufficiently investigated the behavioural and socioeconomic factors that influence exposure. A basic framework is proposed for development of indicators of exposure to environmental health risks that would facilitate the (a) assessment of the health effects of risk factors, (b) design and evaluation of interventions and programmes to deliver the interventions, and (c) appraisal and quantification of inequalities in health effects of risk factors, and benefits of intervention programmes and policies. Specific emphasis is put on the features of environmental risks that should guide the choice of indicators, in particular the interactions of technology, the environment, and human behaviour in determining exposure. The indicators are divided into four categories: (a) access and infrastructure, (b) technology, (c) agents and vectors, and (d) behaviour. The study used water and sanitation, indoor air pollution from solid fuels, urban ambient air pollution, and malaria as illustrative examples for this framework. Organised and systematic indicator selection and monitoring can provide an evidence base for design and implementation of more effective and equitable technological interventions, delivery programmes, and policies for environmental health risks in resource poor settings.

Trace-metal and organic constituent concentrations in bed sediment at Big Base and Little Base Lakes, Little Rock Air Force Base, Arkansas—Comparisons to sediment-quality guidelines and indications for timing of exposure

USGS Publications Warehouse

Justus, B.G.; Hays, Phillip D.; Hart, Rheannon M.

2015-09-16

Regarding highest concentrations and associated timing of exposure, trace metals analyzed in the sediment core seem to indicate three fairly distinct exposure patterns. For 11 trace metals that had the highest concentration measured in the shallowest and most recently deposited sediment, the most likely explanation is recent exposure by anthropogenic activities. Most of the 11 trace metals with highest concentrations in shallow sediment are relatively innocuous; however, arsenic, copper, selenium, and zinc are among the U.S. Environmental Protection Agency’s 126 priority pollutants. For three trace metals (cadmium, lead, and mercury), for which concentrations were highest in sediments that were 16–20 centimeters down the core, it is likely that a source associated with those contaminants during the period when those sediments were deposited, was reduced or eliminated. The eight remaining trace metals, for which concentrations were highest in sediments that were just below the prereservoir surface, likely had sources that were eliminated soon after lake construction or occurred at relatively high background concentrations in soils in the area around Little Rock Air Force Base.

How to estimate exposure when studying the temperature-mortality relationship? A case study of the Paris area.

PubMed

Schaeffer, Laura; de Crouy-Chanel, Perrine; Wagner, Vérène; Desplat, Julien; Pascal, Mathilde

2016-01-01

Time series studies assessing the effect of temperature on mortality generally use temperatures measured by a single weather station. In the Paris region, there is a substantial measurement network, and a variety of exposure indicators created from multiple stations can be tested. The aim of this study is to test the influence of exposure indicators on the temperature-mortality relationship in the Paris region. The relationship between temperature and non-accidental mortality was assessed based on a time series analysis using Poisson regression and a generalised additive model. Twenty-five stations in Paris and its three neighbouring departments were used to create four exposure indicators. These indicators were (1) the temperature recorded by one reference station, (2) a simple average of the temperatures of all stations, (3) an average weighted on the departmental population and (4) a classification of the stations based on land use and an average weighted on the population in each class. The relative risks and the Akaike criteria were similar for all the exposure indicators. The estimated temperature-mortality relationship therefore did not appear to be significantly affected by the indicator used, regardless of study zone (departments or region) or age group. The increase in temperatures from the 90(th) to the 99(th) percentile of the temperature distribution led to a significant increase in mortality over 75 years (RR = 1.10 [95% CI, 1.07; 1.14]). Conversely, the decrease in temperature between the 10(th) and 1(st) percentile had a significant effect on the mortality under 75 years (RR = 1.04 [95% CI, 1.01; 1.06]). In the Paris area, there is no added value in taking multiple climatic stations into account when estimating exposure in time series studies. Methods to better represent the subtle temperature variations in densely populated areas in epidemiological studies are needed.

Risk assessment of drought disaster in southern China

NASA Astrophysics Data System (ADS)

Wang, Y.

2015-12-01

Abstract: Drought has become an increasing concern in southern China, but the drought risk has not been adequately studied. This study presents a method for the spatial assessment of drought risk in southern China using a conceptual framework that emphasizes the combined role of hazard, vulnerability, and exposure.A drought hazard map was retrieved with a compound index of meteorological drought method in a GIS environment. Normally, a large variation in the disaster-inducing factor implies a high probability of economic/social losses caused by a drought disaster. The map indicated that areas with a higher risk of drought hazard were mainly distributed in mid-east Yunnan and the basins in eastern Sichuan.The vulnerability indices were based on climate factors as well as land use, geomorphological types, soil properties, and drainage density. The water preserving capability of purple calcareous soil in the basins in Sichuan and mid-east Yunnan, and the lateritic red soil in northeastern Guangdong is relatively weak. The main geomorphological features in Guangxi and Guangdong are hills, which leads to a serious expectation of soil and water losses. Thus, the main areas with a high risk of drought vulnerability are mid-east Yunnan and the basins in eastern Sichuan.The exposure indices were based on population density and agricultural production because population and agriculture experience the main impacts of a drought disaster. Higher exposure indices mean higher economic/social losses due to drought disasters. Areas with high exposure indices were mainly distributed in Guangdong and southern Guangxi.The overall risk was then calculated as the product of the hazard, vulnerability, and exposure. The results indicated a higher risk of drought disaster in the basins in eastern Sichuan,, northeastern Yunnan, and northeastern Guangdong. The main factor influencing the risk of a drought disaster was the hazard, but the vulnerability and exposure also played important roles.

A solvent-based intelligence ink for oxygen.

PubMed

Mills, Andrew; Hazafy, David

2008-02-01

A solvent-based, irreversible oxygen indicator ink is described, comprising semiconductor photocatalyst nanoparticles, a solvent-soluble redox dye, mild reducing agent and polymer. Based on such an ink, a film -- made of titanium dioxide, a blue, solvent-soluble, coloured ion-paired methylene blue dye, glycerol and the polymer zein -- loses its colour rapidly (<30 s) upon exposure to UVA light and remains colourless in an oxygen-free atmosphere, returning to its original blue colour upon exposure to air. In the latter step the rate of colour recovery is proportional to the level of ambient oxygen and the same film can be UV-activated repeatedly. The mechanism of this novel, UV-activated, solvent-based, colorimetric oxygen indicator is discussed, along with its possible applications.

INFLUENCE OF ALTERNATE INDICATORS OF EXPOSURE TO PM (OR PM COMPONENTS) IN STATISTICAL CORRELATIONS OF EXPOSURE WITH MORTALITY AND MORBIDITY (PHILADELPHIA DATA BASE)

EPA Science Inventory

At the time the 1996 Air Quality Criteria for Particulate Matter Criteria Document was prepared there were several epidemiologic studies using multiple years of TSP and PM10 data for the exposure estimate but only one epidemiologic study using multiple years of PM2.5 data. That ...

Occupational factors and pancreatic cancer.

PubMed Central

Norell, S; Ahlbom, A; Olin, R; Erwald, R; Jacobson, G; Lindberg-Navier, I; Wiechel, K L

1986-01-01

The relation between occupational factors and pancreatic cancer has been studied by two different approaches: a population based case-control study with two series of controls and a retrospective cohort study based on register data. With both approaches, some support was found for an association with occupational exposure to petroleum products. Associations were also indicated with exposure to paint thinner (case-control study) and work in painting and in paint and varnish factories (cohort study), for exposure to detergents, floor cleaning agents, or polish (case-control study) and with floor polishing or window cleaning (cohort study), and for exposure to refuse (case-control study) and work in refuse disposal plants (cohort study). PMID:3790458

Review of genotoxicity biomonitoring studies of glyphosate-based formulations

PubMed Central

Kier, Larry D.

2015-01-01

Abstract Human and environmental genotoxicity biomonitoring studies involving exposure to glyphosate-based formulations (GBFs) were reviewed to complement an earlier review of experimental genotoxicity studies of glyphosate and GBFs. The environmental and most of the human biomonitoring studies were not informative because there was either a very low frequency of GBF exposure or exposure to a large number of pesticides without analysis of specific pesticide effects. One pesticide sprayer biomonitoring study indicated there was not a statistically significant relationship between frequency of GBF exposure reported for the last spraying season and oxidative DNA damage. There were three studies of human populations in regions of GBF aerial spraying. One study found increases for the cytokinesis-block micronucleus endpoint but these increases did not show statistically significant associations with self-reported spray exposure and were not consistent with application rates. A second study found increases for the blood cell comet endpoint at high exposures causing toxicity. However, a follow-up to this study 2 years after spraying did not indicate chromosomal effects. The results of the biomonitoring studies do not contradict an earlier conclusion derived from experimental genotoxicity studies that typical GBFs do not appear to present significant genotoxic risk under normal conditions of human or environmental exposures. PMID:25687244

Bicycle Commuting and Exposure to Air Pollution: A Questionnaire-Based Investigation of Perceptions, Symptoms, and Risk Management Strategies.

PubMed

Cole-Hunter, Tom; Morawska, Lidia; Solomon, Colin

2015-04-01

An increase in bicycle commuting participation may improve public health and traffic congestion in cities. Information on air pollution exposure (such as perception, symptoms, and risk management) contributes to the responsible promotion of bicycle commuting participation. To determine perceptions, symptoms, and willingness for specific exposure risk management strategies of exposure to air pollution, a questionnaire-based cross-sectional investigation was conducted with adult bicycle commuters (n = 153; age = 41 ± 11 years; 28% female). Frequency of acute respiratory signs and symptoms were positively associated with in-commute and postcommute compared with precommute time periods (P < .05); there was greater positive association with respiratory disorder compared with healthy, and female compared with male, participants. The perception (but not signs or symptoms) of in-commute exposure to air pollution was positively associated with the estimated level of in-commute proximity to motorized traffic. The majority of participants indicated a willingness (which varied with health status and gender) to adopt risk management strategies (with desired features) if shown to be appropriate and effective. While acute signs and symptoms of air pollution exposure are indicated with bicycle commuting, and more so in susceptible individuals, there is willingness to manage exposure risk by adopting effective strategies with desired features.

Differential effect of exposure-based therapy and cognitive therapy on post-traumatic stress disorder symptom clusters: A randomized controlled trial.

PubMed

Horesh, Danny; Qian, Meng; Freedman, Sara; Shalev, Arieh

2017-06-01

A question remains regarding differential effects of exposure-based versus non-exposure-based therapies on specific post-traumatic stress disorder (PTSD) symptom clusters. Traumatized emergency room patients were randomized to receive prolonged exposure (PE) or cognitive therapy (CT) without exposure. PE/CT had no differential effect on individual symptom clusters, and change in total PTSD score remained significant even after controlling for the reductions in all three symptom clusters. In addition, baseline levels of PTSD avoidance/intrusion/hyperarousal did not moderate the effects of PE and CT on total PTSD symptom scores. Taken together, these findings challenge the notion that PE and CT are specifically, and differentially, useful in treating one particular PTSD symptom cluster. Despite their different theoretical backgrounds and techniques, the notion that PE and CT (without exposure) target different PTSD symptoms was not confirmed in this study. Thus, both interventions may in fact be equally effective for treating intrusion, avoidance and hyperarousal symptoms. Baseline levels of avoidance, intrusion and hyperarousal may not be good a priori indicators for PTSD treatment selection. The effect of PE and CT on PTSD as a whole does not seem to depend on a reduction in any specific symptom cluster. These findings indicate that exposure and non-exposure interventions may lead to similar results in terms of reductions in specific PTSD symptoms. It is quite possible that individual PTSD clusters may respond to therapy in an inter-related fashion, with one cluster affecting the other. © 2016 The British Psychological Society.

Biomarkers of Exposure to Toxic Substances. Volume 2: Genomics: Unique Patterns of Differential Gene Expression and Pathway Perturbation Resulting from Exposure to Nephrotoxins with Regional Specific Toxicity

DTIC Science & Technology

2009-05-01

of chemicals agents . Changes in gene expression are among the most sensitive indicators of chemical exposure. Toxicogenomics, which is based on DNA...assessing gene expression changes and subsequently the mechanism of renal injury following exposure to nephrotoxins selected for their regional...Serine Treatment on Selected Serum Chemistry Parameters ........................ 8 Table 4: Effect of PUR Treatment on Selected Serum Chemistry

Physical and sexual violence, mental health indicators, and treatment seeking among street-based population groups in Tegucigalpa, Honduras.

PubMed

Rio Navarro, Javier; Cohen, Julien; Rocillo Arechaga, Eva; Zuniga, Edgardo

2012-05-01

To establish the prevalence of exposure to physical and sexual violence, mental health symptoms, and medical treatment-seeking behavior among three street-based subpopulation groups in Tegucigalpa, Honduras, and to assess the association between sociodemographic group, mental health indicators, and exposure to violence. An anonymous, cross-sectional survey among randomly selected street-based adolescents, adults, and commercial sex workers (CSWs) was undertaken at the end of 2010 in Tegucigalpa. Médecins Sans Frontières (MSF) mapped places where the study population gathers. Stratified probability samples were drawn for all groups, using two-stage random sampling. Trained MSF staff administered on-site standardized face-to-face questionnaires. Self-reported exposure to severe physical violence in the previous year was 20.9% among street-based adolescents, 28.8% among adults, and 30.6% among CSWs. For the physical violence event self-defined as most severe, 50.0% of the adolescents, 81.4% of the adults, and 70.6% of the CSWs sought medical treatment. Their exposure to severe sexual violence was 8.6%, 28.8%, and 59.2%, respectively. After exposure to the self-defined most severe sexual violence event, 14.3% of adolescents, 31.9% of adults, and 29.1% of CSWs sought treatment. Common mental health and substance abuse symptoms were highly prevalent and strongly associated with exposure to physical (odds ratio 4.5, P < 0.0001) and sexual (odds ratio 3.7, P = 0.0001) violence. Exposure to physical and sexual violence reached extreme levels among street-based subpopulations. Treatment-seeking behavior, particularly after severe sexual violence, was limited. The association of mental health and substance abuse symptoms with exposure to violence could lead to further victimization. Medical and psychological treatments targeting these groups are needed and could help decrease their vulnerability.

Daily intake and hazard index of parabens based upon 24 h urine samples of the German Environmental Specimen Bank from 1995 to 2012.

PubMed

Moos, Rebecca K; Apel, Petra; Schröter-Kermani, Christa; Kolossa-Gehring, Marike; Brüning, Thomas; Koch, Holger M

2017-11-01

In recent years, exposure to parabens has become more of a concern because of evidence of ubiquitous exposure in the general population, combined with evidence of their potency as endocrine disruptors. New human metabolism data from oral exposure experiments enable us to back calculate daily paraben intakes from urinary paraben levels. We report daily intakes (DIs) for six parabens based on 660 24 h urine samples from the German Environmental Specimen Bank collected between 1995 and 2012. Median DI values ranged between 1.1 μg/kg bw/day for iso-butyl paraben and 47.5 μg/kg bw/day for methyl paraben. The calculated DIs were compared with acceptable levels of exposure to evaluate the hazard quotients (HQs) that indicate that acceptable exposure is exceeded for values of >1. Approximately 5% of our study population exceeded this threshold for individual paraben exposure. The hazard index (HI) that takes into account the cumulative risk of adverse estrogenic effects was 1.3 at the 95th percentile and 4.4 at maximum intakes, mainly driven by n-propyl paraben exposure. HI values of >1 indicate some level of concern. However, we have to point out that we applied most conservative assumptions in the HQ/HI calculations. Also, major exposure reduction measures were enacted in the European Union after 2012.

Manganese in exhaled breath condensate: a new marker of exposure to welding fumes.

PubMed

Hulo, Sébastien; Chérot-Kornobis, Nathalie; Howsam, Mike; Crucq, Sébastien; de Broucker, Virginie; Sobaszek, Annie; Edme, Jean-Louis

2014-04-07

To evaluate manganese in exhaled breath condensate (Mn-EBC) as an indicator of exposure to fumes from metal inert gas welding process. We collected EBC and urine from 17 welders and 16 unexposed control subjects after 5 days exposure. Concentrations of manganese (Mn), nickel (Ni), iron (Fe) and chromium (Cr) were measured in EBC and urine samples and correlated with cumulative exposure indices for the working week (CIW) and for the total welding years (WY), based on duration of welding activity and atmospheric metal measurements. Concentrations of Mn and Ni in EBC were significantly higher among welders than controls whereas this difference was not significant for Mn in urine. Levels of Mn and Ni in EBC were not correlated with their respective levels in urine. The linear regressions found significant positive coefficients between Mn-EBC, Ni-EBC, Ni-U and Cr-U concentrations and the cumulative exposure indices. Taking into account tobacco use, statistical analysis showed the same trends except for the relationship between Mn-U and CIW. This pilot study showed that Mn-EBC, as well as Ni-EBC, can serve as reliable indices of occupational exposure to welding fumes and provide complimentary toxicokinetic information to that provided by urine analyses. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Incorporating peer support during in vivo exposure to reverse dropout from prolonged exposure therapy for posttraumatic stress disorder: Clinical outcomes.

PubMed

Hernandez-Tejada, Melba A; Hamski, Stephanie; Sánchez-Carracedo, David

2017-01-01

Objective Prolonged exposure is characterized by reported dropout rates ranging from 25% to 40%. This premature attrition is also observed in other evidence-based treatments for posttraumatic stress disorder. While home-based telehealth delivery of prolonged exposure resolves logistical barriers to care such as travel time and cost, dropout appears unaffected. A previous study on dropouts from prolonged exposure delivered via telehealth found that Veterans, particularly those receiving care via telehealth, reported problems with in vivo exposure and that having a peer to offer support during in vivo exposure assignments might have prevented their attrition from treatment. Methods The present pilot study treatment was designed in a manner consistent with the aforementioned Veteran suggestions, specifically to involve peers offering verbal support and encouragement during in vivo exposure homework. Such a treatment modification might be particularly useful for those receiving care via telehealth, given increased difficulties with exposure reported when this treatment delivery modality is used. It was hypothesized that dropouts would agree to reengage in treatment with a peer and would subsequently evince improvement in posttraumatic stress disorder and depression scores as a result of this treatment reengagement. Results Of 82 dropouts from prolonged exposure, 29 reentered treatment when offered peer support during exposure (12 in telehealth and 17 in person). Conclusion Treatment reentry was effective insofar as indices of both posttraumatic stress disorder and depression were significantly reduced in both telehealth and in person groups, indicating that using peers in this way may be an effective means by which to return Veterans to care, and ultimately reduce symptomatology.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lea, C.S.; Selvin, S.; Buffler, P.A.

This pilot study uses a unique method to calculate cumulative lifetime exposure to, ultraviolet radiation-b to determine if this refined method would indicate differences in lifetime cumulative UVB exposure between age and sex matched controls. Forty-four age and sex matched cases and controls demonstrated no significant difference in mean cumulative lifetime UVB exposure based on the duration and location of residence. This pilot study suggests that further analysis of the dataset should be conducted to determine if the cumulative lifetime exposure hypothesis is of primary importance regarding the association between UVB exposure and development of cutaneous malignant melanoma.

SMALL AIRWAYS FUNCTION RESPONSE IN SMOKERS AND PATIENTS WITH CHRONIC OBSTRUCTIVE LUNG DISEASE FOLLOWING EXPOSURE TO CONCENTRATED AMBIENT AIR PARTICLES

EPA Science Inventory

Numerous field and epidemiological studies have shown significant associations between particulate matter (PM) exposure and various morbidity outcomes including hospital admissions for bronchitis and asthma. These population based studies indicate that persons with chronic obstru...

[Biomarkers of gentotoxic risk and metabolic polymorphism].

PubMed

Pavanello, S; Clonfero, E

2000-01-01

This paper reviews studies published in the international scientific literature evaluating the influence of genetically based metabolic polymorphisms on biological indicators of genotoxic risk in environmental or occupational exposure. Exposures due to life style (i.e. diet or smoking) were not considered. Indicators are subdivided into internal dose indicators (concentration of the substance or its metabolites in biological fluids, urinary mutagenicity, adducts of hemoglobin, plasma proteins and DNA), and early biological effects (chromosome aberrations, sister chromatid exchanges, micronuclei, COMET assay, HPRT mutants). The metabolic genotypes (or phenotypes) examined by various authors are: ALDH2 (aldehyde dehydrogenase), CYP (P450 cytochrome) 1AI, CYP1A2, CYP2E1, CYP2D6, EPHX (epoxidohydrolase), NAT2 (N-acetyl transferase), NQO1 (NAD(P)H: kinone oxidoreductase), PON1 (paraoxonase), GST (glutathione S-transferase) M1, GSTT1 and GSTP1. In more than half the studies (52 out of 96), no influence of genotype was found in the biological indicator. This may be due either to the poor sensitivity of the indicator used, or to low exposure. In studies examining the effect of genotype on the indicator, the biological plausibility of the result was evaluated, i.e., whether the effect is consistent with the type of enzymatic activity expressed. Four studies reported not very reliable results and suggest either the unfavourable influence of genotype GSTM1 with high detoxifying activity, or enzymatic activity poorly involved in the metabolism of the xenobiotics in question (NAT2 in the case of PAH). As regards urinary metabolites of genotoxic agents, eight studies reported the modulating effect of genotype. The urinary excretion of mercapturic acids was greater in subjects with high GST activity. In exposure to PAH, urinary 1-pyrenol and PAH metabolites turn out to be significantly influenced by genotypes CYP1A1 or GSTM1 null; in exposure to aromatic amines, the influence of NAT2 on exposure indicators (levels of acetylated and non-acetylated metabolites) was confirmed. Exposure to benzene led to an increase in t-t-MA in some genotypes, although experimental verification is still necessary. As regards urinary mutagenicity, the effect of genotype GSTM1 null is reported, and of the same genotype combined with NAT2 slow, in non-smoking individuals subjected to high exposure to PAH and in cigarette-smoking/coke-oven workers. Lastly, the determination of urinary metabolites in monitoring exposure to genotoxic substances, provides sufficient evidence that genetically based metabolic polymorphisms must be taken into account in the future. There is still little evidence regarding the importance of genotype on the level of protein adducts in environmental and occupational exposure. A relatively large number of publications (22) dealt with DNA adduct levels in PAH exposure. In 18 studies, the biological indicator clearly increases with respect to values in control subjects. Of these studies, seven reported the influence of GSTM1 null on DNA adducts and, of the five studies which also examined genotype CYP1A1, four reported the influence on DNA adduct level of genotype CYP1A1, alone or in combination with GSTM1 null. It therefore seems as if the unfavourable association for the activating/detoxifying metabolism of PAH is a risk factor for the formation of PAH-DNA adducts. Most publications (25 out of 41; 61%) dealing with metabolic polymorphisms in effect indicators (cytogenetic markers, COMET assay, HPRT mutants) did not report any increase in the indicator due to exposure to the genotoxic agents studied. These indicators of genotoxic damage, including mainly the frequency of HPRT mutants (100%), Mn (90%) and the COMET assay (67%), are not sufficiently sensitive in revealing exposure, confirming that they are not particularly suitable for measuring exposure to genotoxic substances in occupational or environmental exposures. It is therefore difficult to assess the influence of metabolic genotypes by means of this type of biological indicator. The few positive results reported for SCE in occupational studies mentioned the influence of genotype ALDH2, either alone or in combination with genotype CYP2E1 in exposure to CVM, or in combination with GSTM1 null in exposure to epichlorohydrin. For CA the results showed unfavourable combinations of genotypes CYP2E1, GSTM1 and PON1 in exposure to pesticides, and GSTM1 null in combination with NAT2 slow in exposure to urban air. All the remaining studies on the effect of genotype on biological indicators of cytogenetic damage reported negative results.

A dose-dependent relationship between exposure to a street-based drug scene and health-related harms among people who use injection drugs.

PubMed

Debeck, Kora; Wood, Evan; Zhang, Ruth; Buxton, Jane; Montaner, Julio; Kerr, Thomas

2011-08-01

While the community impacts of drug-related street disorder have been well described, lesser attention has been given to the potential health and social implications of drug scene exposure on street-involved people who use illicit drugs. Therefore, we sought to assess the impacts of exposure to a street-based drug scene among injection drug users (IDU) in a Canadian setting. Data were derived from a prospective cohort study known as the Vancouver Injection Drug Users Study. Four categories of drug scene exposure were defined based on the numbers of hours spent on the street each day. Three generalized estimating equation (GEE) logistic regression models were constructed to identify factors associated with varying levels of drug scene exposure (2-6, 6-15, over 15 hours) during the period of December 2005 to March 2009. Among our sample of 1,486 IDU, at baseline, a total of 314 (21%) fit the criteria for high drug scene exposure (>15 hours per day). In multivariate GEE analysis, factors significantly and independently associated with high exposure included: unstable housing (adjusted odds ratio [AOR] = 9.50; 95% confidence interval [CI], 6.36-14.20); daily crack use (AOR = 2.70; 95% CI, 2.07-3.52); encounters with police (AOR = 2.11; 95% CI, 1.62-2.75); and being a victim of violence (AOR = 1.49; 95 % CI, 1.14-1.95). Regular employment (AOR = 0.50; 95% CI, 0.38-0.65), and engagement with addiction treatment (AOR = 0.58; 95% CI, 0.45-0.75) were negatively associated with high exposure. Our findings indicate that drug scene exposure is associated with markers of vulnerability and higher intensity addiction. Intensity of drug scene exposure was associated with indicators of vulnerability to harm in a dose-dependent fashion. These findings highlight opportunities for policy interventions to address exposure to street disorder in the areas of employment, housing, and addiction treatment.

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

PubMed

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

2018-02-01

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

Essential Indicators Identifying Chronic Inorganic Mercury Intoxication: Pooled Analysis across Multiple Cross-Sectional Studies.

PubMed

Doering, Stefan; Bose-O'Reilly, Stephan; Berger, Ursula

2016-01-01

The continuous exposure to inorganic mercury vapour in artisanal small-scale gold mining (ASGM) areas leads to chronic health problems. It is therefore essential to have a quick, but reliable risk assessing tool to diagnose chronic inorganic mercury intoxication. This study re-evaluates the state-of-the-art toolkit to diagnose chronic inorganic mercury intoxication by analysing data from multiple pooled cross-sectional studies. The primary research question aims to reduce the currently used set of indicators without affecting essentially the capability to diagnose chronic inorganic mercury intoxication. In addition, a sensitivity analysis is performed on established biomonitoring exposure limits for mercury in blood, hair, urine and urine adjusted by creatinine, where the biomonitoring exposure limits are compared to thresholds most associated with chronic inorganic mercury intoxication in artisanal small-scale gold mining. Health data from miners and community members in Indonesia, Tanzania and Zimbabwe were obtained as part of the Global Mercury Project and pooled into one dataset together with their biomarkers mercury in urine, blood and hair. The individual prognostic impact of the indicators on the diagnosis of mercury intoxication is quantified using logistic regression models. The selection is performed by a stepwise forward/backward selection. Different models are compared based on the Bayesian information criterion (BIC) and Cohen`s kappa is used to evaluate the level of agreement between the diagnosis of mercury intoxication based on the currently used set of indicators and the result based on our reduced set of indicators. The sensitivity analysis of biomarker exposure limits of mercury is based on a sequence of chi square tests. The variable selection in logistic regression reduced the number of medical indicators from thirteen to ten in addition to the biomarkers. The estimated level of agreement using ten of thirteen medical indicators and all four biomarkers to diagnose chronic inorganic mercury intoxication yields a Cohen`s Kappa of 0.87. While in an additional stepwise selection the biomarker blood was not selected, the level of agreement based on ten medical indicators and only the three biomarkers urine, urine/creatinine and hair reduced Cohen`s Kappa to 0.46. The optimal cut-point for the biomarkers blood, hair, urine and urine/creatinine were estimated at 11. 6 μg/l, 3.84 μg/g, 24.4 μg/l and 4.26 μg/g, respectively. The results show that a reduction down to only ten indicators still allows a reliable diagnosis of chronic inorganic mercury intoxication. This reduction of indicators will simplify health assessments in artisanal small-scale gold mining areas.

Fine particulate air pollution and all-cause mortality within the Harvard Six-Cities Study: variations in risk by period of exposure.

PubMed

Villeneuve, Paul J; Goldberg, Mark S; Krewski, Daniel; Burnett, Richard T; Chen, Yue

2002-11-01

We used Poisson regression methods to examine the relation between temporal changes in the levels of fine particulate air pollution (PM(2.5)) and the risk of mortality among participants of the Harvard Six Cities longitudinal study. Our analyses were based on 1430 deaths that occurred between 1974 and 1991 in a cohort that accumulated 105,714 person-years of follow-up. For each city, indices of PM(2.5) were derived using daily samples. Individual level data were collected on several risk factors including: smoking, education, body mass index (BMI), and occupational exposure to dusts. Time-dependent indices of PM(2.5) were created across 13 calendar periods (< 1979, 1979, 1980, em leader, 1989, >/= 1990) to explore whether recent or chronic exposures were more important predictors of mortality. The relative risk (RR) of mortality calculated using Poisson regression based on average city-specific exposures that remained constant during follow-up was 1.31 [95% confidence interval (CI) = 1.12-1.52] per 18.6 microg/m(3) of PM(2.5). This result was similar to the risk calculated using the Cox model (RR = 1.26, 95% CI = 1.08-1.46). The RR of mortality was attenuated when the Poisson regression model included a time-dependent estimate of exposure (RR = 1.19, 95% CI = 1.04-1.36). There was little variation in RR across time-dependent indices of PM(2.5). The attenuated risk of mortality that was observed with a time-dependent index of PM(2.5) is due to the combined influence of city-specific variations in mortality rates and decreasing levels of air pollution that occurred during follow-up. The RR of mortality associated with PM(2.5) did not depend on when exposure occurred in relation to death, possibly because of little variation between the time-dependent city-specific exposure indices.

New regression model for predicting hand-arm vibration (HAV) of Malaysian Army (MA) three-tonne truck steering wheels.

PubMed

Aziz, Shamsul Akmar Ab; Nuawi, Mohd Zaki; Nor, Mohd Jailani Mohd

2015-01-01

The objective of this study was to present a new method for determination of hand-arm vibration (HAV) in Malaysian Army (MA) three-tonne truck steering wheels based on changes in vehicle speed using regression model and the statistical analysis method known as Integrated Kurtosis-Based Algorithm for Z-Notch Filter Technique Vibro (I-kaz Vibro). The test was conducted for two different road conditions, tarmac and dirt roads. HAV exposure was measured using a Brüel & Kjær Type 3649 vibration analyzer, which is capable of recording HAV exposures from steering wheels. The data was analyzed using I-kaz Vibro to determine the HAV values in relation to varying speeds of a truck and to determine the degree of data scattering for HAV data signals. Based on the results obtained, HAV experienced by drivers can be determined using the daily vibration exposure A(8), I-kaz Vibro coefficient (Ƶ(v)(∞)), and the I-kaz Vibro display. The I-kaz Vibro displays also showed greater scatterings, indicating that the values of Ƶ(v)(∞) and A(8) were increasing. Prediction of HAV exposure was done using the developed regression model and graphical representations of Ƶ(v)(∞). The results of the regression model showed that Ƶ(v)(∞) increased when the vehicle speed and HAV exposure increased. For model validation, predicted and measured noise exposures were compared, and high coefficient of correlation (R(2)) values were obtained, indicating that good agreement was obtained between them. By using the developed regression model, we can easily predict HAV exposure from steering wheels for HAV exposure monitoring.

The 737 graphite composite flight spoiler flight service evaluation

NASA Technical Reports Server (NTRS)

Stoecklin, R. L.

1976-01-01

The flight-service experience of 110 graphite-epoxy spoilers on 737 transport aircraft and related ground-based environmental exposure of graphite-epoxy material specimens is reported. Spoilers were installed on each of 27 aircraft representing seven major airlines operating throughout the world. Based on visual, ultrasonic, and destructive testing, there is no evidence of moisture migration into the honeycomb core and no core corrosion. Tests of removed spoilers and of ground-based exposure specimens after the second year of service indicate modest changes in composite strength.

Endocrine disrupting chemicals in fish: developing exposure indicators and predictive models of effects based on mechanism of action

EPA Science Inventory

Knowledge of possible toxic mechanisms/modes of action (MOA) of chemicals can provide valuable insights as to appropriate methods for assessing exposure and effects, such as reducing uncertainties related to extrapolation across species, endpoints and chemical structure. However,...

ANTS AS INDICATORS OF EXPOSURE TO ENVIRONMENTAL STRESSORS IN NORTH AMERICAN DESERT GRASSLANDS

EPA Science Inventory

The relative abundance of ant species was measured by pit-fall trapping at 44 sites in southern New Mexico and southeastern Arizona, U.S.A..Sites were selected for study based on documentation of a history of disturbance or protection from disturbance, exposure to varying intens...

Allergens in household dust and serological indicators of atopy and sensitization in Detroit children with history--based eivdence of asthma

EPA Science Inventory

BACKGROUND: Home exposure to allergens is an important factor in the development of sensitization and subsequent exacerbations of allergic asthma. We investigated linkages among allergen exposure, immunological measurements, and asthma by examining (1) reservoir dust allergen lev...

Exposure to acute severe hypoxia leads to increased urea loss and disruptions in acid-base and ionoregulatory balance in dogfish sharks (Squalus acanthias).

PubMed

Zimmer, Alex M; Wood, Chris M

2014-01-01

The effects of acute moderate (20% air O2 saturation; 6-h exposure) and severe (5% air O2 saturation; 4-h exposure) hypoxia on N-waste, acid-base, and ion balance in dogfish sharks (Squalus acanthias suckleyi) were evaluated. We predicted that the synthesis and/or retention of urea, which are active processes, would be inhibited by hypoxia. Exposure to moderate hypoxia had negligible effects on N-waste fluxes or systemic physiology, except for a modest rise in plasma lactate. Exposure to severe hypoxia led to a significant increase in urea excretion (Jurea), while plasma, liver, and muscle urea concentrations were unchanged, suggesting a loss of urea retention. Ammonia excretion (Jamm) was elevated during normoxic recovery. Moreover, severe hypoxia led to disruptions in acid-base balance, indicated by a large increase in plasma [lactate] and substantial decreases in arterial pHa and plasma [Formula: see text], as well as loss of ionic homeostasis, indicated by increases in plasma [Mg(2+)], [Ca(2+)], and [Na(+)]. We suggest that severe hypoxia in dogfish sharks leads to a reduction in active gill homeostatic processes, such as urea retention, acid-base regulation and ionoregulation, and/or an osmoregulatory compromise due to increased functional gill surface area. Overall, the results provide a comprehensive picture of the physiological responses to a severe degree of hypoxia in an ancient fish species.

Risk-Exposure Density and Mileage Bias in Crash Risk for Older Drivers

PubMed Central

Rolison, Jonathan J; Moutari, Salissou

2018-01-01

Abstract Crash rates per mile indicate a high risk of vehicle crash in older drivers. A reliance on mileage alone may underestimate the risk exposure of older drivers because they tend to avoid highways and travel more on nonfreeways (e.g., urban roads), which present greater hazards. We introduce risk-exposure density as an index of exposure that incorporates mileage, frequency of travel, and travel duration. Population-wide driver fatalities in the United States during 2002–2012 were assessed according to driver age range (in years: 16–20, 21–29, 30–39, 40–49, 50–59, 60–69, ≥70) and sex. Mileage, frequency, and duration of travel per person were used to assess risk exposure. Mileage-based fatal crash risk increased greatly among male (relative risk (RR) = 1.73; 95% CI: 1.62, 1.83) and female (RR = 2.08; 95% CI: 1.97, 2.19) drivers from ages 60–69 years to ages ≥70 years. Adjusting for their density of risk exposure, fatal crash risk increased only slightly from ages 60–69 years to ages ≥70 years among male (RR = 1.09; 95% CI: 1.03, 1.15) and female (RR = 1.22; 95% CI: 1.16, 1.29) drivers. While ubiquitous in epidemiologic research, mileage-based assessments can produce misleading accounts of driver risk. Risk-exposure density incorporates multiple components of travel and reduces bias caused by any single indicator of risk exposure. PMID:28605422

Blood miRNAs as sensitive and specific biological indicators of environmental and occupational exposure to volatile organic compound (VOC).

PubMed

Song, Mi-Kyung; Ryu, Jae-Chun

2015-10-01

To date, there is still shortage of highly sensitive and specific minimally invasive biomarkers for assessment of environmental toxicants exposure. Because of the significance of microRNA (miRNA) in various diseases, circulating miRNAs in blood may be unique biomarkers for minimally invasive prediction of toxicants exposure. We identified and validated characteristic miRNA expression profiles of human whole blood in workers exposed to volatile organic compounds (VOCs) and compared the usefulness of miRNA indicator of VOCs with the effectiveness of the already used urinary biomarkers of occupational exposure. Using a microarray based approach we screened and detected deregulated miRNAs in their expression in workers exposed to VOCs (toluene [TOL], xylene [XYL] and ethylbenzene [EBZ]). Total 169 workers from four dockyards were enrolled in current study, and 50 subjects of them were used for miRNA microarray analysis. We identified 467 miRNAs for TOL, 211 miRNAs for XYL, and 695 miRNAs for XYL as characteristic discernible exposure indicator, which could discerned each VOC from the control group with higher accuracy, sensitivity, and specificity than urinary biomarkers. Current observations from this study point out that the altered levels of circulating miRNAs can be a reliable novel, minimally invasive biological indicator of occupational exposure to VOCs. Copyright © 2015 Elsevier GmbH. All rights reserved.

Measuring accident risk exposure for pedestrians in different micro-environments.

PubMed

Lassarre, Sylvain; Papadimitriou, Eleonora; Yannis, George; Golias, John

2007-11-01

Pedestrians are mainly exposed to the risk of road accident when crossing a road in urban areas. Traditionally in the road safety field, the risk of accident for pedestrian is estimated as a rate of accident involvement per unit of time spent on the road network. The objective of this research is to develop an approach of accident risk based on the concept of risk exposure used in environmental epidemiology, such as in the case of exposure to pollutants. This type of indicator would be useful for comparing the effects of urban transportation policy scenarios on pedestrian safety. The first step is to create an indicator of pedestrians' exposure, which is based on motorised vehicles' "concentration" by lane and also takes account of traffic speed and time spent to cross. This is applied to two specific micro-environments: junctions and mid-block locations. A model of pedestrians' crossing behaviour along a trip is then developed, based on a hierarchical choice between junctions and mid-block locations and taking account of origin and destination, traffic characteristics and pedestrian facilities. Finally, a complete framework is produced for modelling pedestrians' exposure in the light of their crossing behaviour. The feasibility of this approach is demonstrated on an artificial network and a first set of results is obtained from the validation of the models in observational studies.

Impact of pesticide exposure misclassification on estimates of relative risks in the Agricultural Health Study.

PubMed

Blair, Aaron; Thomas, Kent; Coble, Joseph; Sandler, Dale P; Hines, Cynthia J; Lynch, Charles F; Knott, Charles; Purdue, Mark P; Zahm, Shelia Hoar; Alavanja, Michael C R; Dosemeci, Mustafa; Kamel, Freya; Hoppin, Jane A; Freeman, Laura Beane; Lubin, Jay H

2011-07-01

The Agricultural Health Study (AHS) is a prospective study of licensed pesticide applicators and their spouses in Iowa and North Carolina. We evaluate the impact of occupational pesticide exposure misclassification on relative risks using data from the cohort and the AHS Pesticide Exposure Study (AHS/PES). We assessed the impact of exposure misclassification on relative risks using the range of correlation coefficients observed between measured post-application urinary levels of 2,4-dichlorophenoxyacetic acid (2,4-D) and a chlorpyrifos metabolite and exposure estimates based on an algorithm from 83 AHS pesticide applications. Correlations between urinary levels of 2,4-D and a chlorpyrifos metabolite and algorithm estimated intensity scores were about 0.4 for 2,4-D (n=64), 0.8 for liquid chlorpyrifos (n=4) and 0.6 for granular chlorpyrifos (n=12). Correlations of urinary levels with kilograms of active ingredient used, duration of application, or number of acres treated were lower and ranged from -0.36 to 0.19. These findings indicate that a priori expert-derived algorithm scores were more closely related to measured urinary levels than individual exposure determinants evaluated here. Estimates of potential bias in relative risks based on the correlations from the AHS/PES indicate that non-differential misclassification of exposure using the algorithm would bias estimates towards the null, but less than that from individual exposure determinants. Although correlations between algorithm scores and urinary levels were quite good (ie, correlations between 0.4 and 0.8), exposure misclassification would still bias relative risk estimates in the AHS towards the null and diminish study power.

Modelling of occupational respirable crystalline silica exposure for quantitative exposure assessment in community-based case-control studies.

PubMed

Peters, Susan; Vermeulen, Roel; Portengen, Lützen; Olsson, Ann; Kendzia, Benjamin; Vincent, Raymond; Savary, Barbara; Lavoué, Jérôme; Cavallo, Domenico; Cattaneo, Andrea; Mirabelli, Dario; Plato, Nils; Fevotte, Joelle; Pesch, Beate; Brüning, Thomas; Straif, Kurt; Kromhout, Hans

2011-11-01

We describe an empirical model for exposure to respirable crystalline silica (RCS) to create a quantitative job-exposure matrix (JEM) for community-based studies. Personal measurements of exposure to RCS from Europe and Canada were obtained for exposure modelling. A mixed-effects model was elaborated, with region/country and job titles as random effect terms. The fixed effect terms included year of measurement, measurement strategy (representative or worst-case), sampling duration (minutes) and a priori exposure intensity rating for each job from an independently developed JEM (none, low, high). 23,640 personal RCS exposure measurements, covering a time period from 1976 to 2009, were available for modelling. The model indicated an overall downward time trend in RCS exposure levels of -6% per year. Exposure levels were higher in the UK and Canada, and lower in Northern Europe and Germany. Worst-case sampling was associated with higher reported exposure levels and an increase in sampling duration was associated with lower reported exposure levels. Highest predicted RCS exposure levels in the reference year (1998) were for chimney bricklayers (geometric mean 0.11 mg m(-3)), monument carvers and other stone cutters and carvers (0.10 mg m(-3)). The resulting model enables us to predict time-, job-, and region/country-specific exposure levels of RCS. These predictions will be used in the SYNERGY study, an ongoing pooled multinational community-based case-control study on lung cancer.

A Method for Semi-quantitative Assessment of Exposure to Pesticides of Applicators and Re-entry Workers: An Application in Three Farming Systems in Ethiopia.

PubMed

Negatu, Beyene; Vermeulen, Roel; Mekonnen, Yalemtshay; Kromhout, Hans

2016-07-01

To develop an inexpensive and easily adaptable semi-quantitative exposure assessment method to characterize exposure to pesticide in applicators and re-entry farmers and farm workers in Ethiopia. Two specific semi-quantitative exposure algorithms for pesticides applicators and re-entry workers were developed and applied to 601 farm workers employed in 3 distinctly different farming systems [small-scale irrigated, large-scale greenhouses (LSGH), and large-scale open (LSO)] in Ethiopia. The algorithm for applicators was based on exposure-modifying factors including application methods, farm layout (open or closed), pesticide mixing conditions, cleaning of spraying equipment, intensity of pesticide application per day, utilization of personal protective equipment (PPE), personal hygienic behavior, annual frequency of application, and duration of employment at the farm. The algorithm for re-entry work was based on an expert-based re-entry exposure intensity score, utilization of PPE, personal hygienic behavior, annual frequency of re-entry work, and duration of employment at the farm. The algorithms allowed estimation of daily, annual and cumulative lifetime exposure for applicators, and re-entry workers by farming system, by gender, and by age group. For all metrics, highest exposures occurred in LSGH for both applicators and female re-entry workers. For male re-entry workers, highest cumulative exposure occurred in LSO farms. Female re-entry workers appeared to be higher exposed on a daily or annual basis than male re-entry workers, but their cumulative exposures were similar due to the fact that on average males had longer tenure. Factors related to intensity of exposure (like application method and farm layout) were indicated as the main driving factors for estimated potential exposure. Use of personal protection, hygienic behavior, and duration of employment in surveyed farm workers contributed less to the contrast in exposure estimates. This study indicated that farmers' and farm workers' exposure to pesticides can be inexpensively characterized, ranked, and classified. Our method could be extended to assess exposure to specific active ingredients provided that detailed information on pesticides used is available. The resulting exposure estimates will consequently be used in occupational epidemiology studies in Ethiopia and other similar countries with few resources. © The Author 2016. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Workplace air measurements and likelihood of exposure to manufactured nano-objects, agglomerates, and aggregates

NASA Astrophysics Data System (ADS)

Brouwer, Derk H.; van Duuren-Stuurman, Birgit; Berges, Markus; Bard, Delphine; Jankowska, Elzbieta; Moehlmann, Carsten; Pelzer, Johannes; Mark, Dave

2013-11-01

Manufactured nano-objects, agglomerates, and aggregates (NOAA) may have adverse effect on human health, but little is known about occupational risks since actual estimates of exposure are lacking. In a large-scale workplace air-monitoring campaign, 19 enterprises were visited and 120 potential exposure scenarios were measured. A multi-metric exposure assessment approach was followed and a decision logic was developed to afford analysis of all results in concert. The overall evaluation was classified by categories of likelihood of exposure. At task level about 53 % showed increased particle number or surface area concentration compared to "background" level, whereas 72 % of the TEM samples revealed an indication that NOAA were present in the workplace. For 54 out of the 120 task-based exposure scenarios, an overall evaluation could be made based on all parameters of the decision logic. For only 1 exposure scenario (approximately 2 %), the highest level of potential likelihood was assigned, whereas in total in 56 % of the exposure scenarios the overall evaluation revealed the lowest level of likelihood. However, for the remaining 42 % exposure to NOAA could not be excluded.

Surgery for subacromial impingement syndrome in relation to intensities of occupational mechanical exposures across 10-year exposure time windows.

PubMed

Dalbøge, Annett; Frost, Poul; Andersen, Johan Hviid; Svendsen, Susanne Wulff

2018-03-01

We aimed to identify intensities of occupational mechanical exposures (force, arm elevation and repetition) that do not entail an increased risk of surgery for subacromial impingement syndrome (SIS) even after prolonged durations of exposure. Additionally, we wanted to evaluate if exposure to hand-arm vibration (HAV) is an independent risk factor. We used data from a register-based cohort study of the entire Danish working population (n=2 374 403). During follow-up (2003-2008), 14 118 first-time events of surgery for SIS occurred. For each person, we linked register-based occupational codes (1993-2007) to a general population job exposure matrix to obtain year-by-year exposure intensities on measurement scales for force, upper arm elevation >90° and repetition and expert rated intensities of exposure to HAV. For 10-year exposure time windows, we calculated the duration of exposure at specific intensities above minimal (low, medium and high). We used a logistic regression technique equivalent to discrete survival analysis adjusting for cumulative effects of other mechanical exposures. We found indications of safe exposure intensities for repetition (median angular velocity <45°/s), while force exertion ≥10% of maximal voluntary electrical activity and upper arm elevation >90° >2 min/day implied an increased risk reaching ORs of 1.7 and 1.5 after 10 years at low intensities. No associations were found for HAV. We found indications of safe exposure intensities for repetition. Any intensities of force and upper arm elevation >90° above minimal implied an increased risk across 10-year exposure time windows. No independent associations were found for HAV. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Neuronal stress following exposure to 56Fe particles and the effects of antioxidant-rich diets

USDA-ARS?s Scientific Manuscript database

Exposing young rats to particles of high energy and charge (HZE particles), a ground-based model for exposure to cosmic rays, enhances indices of oxidative stress and inflammation and disrupts the functioning of neuronal communication in critical regions of the brain. These changes in neuronal funct...

Neuronal stress following exposure to 56Fe particles and the effects of antioxidant-rich diets

USDA-ARS?s Scientific Manuscript database

Exposing young rats to particles of high energy and charge (HZE particles), a ground-based model for exposure to cosmic rays, enhances indices of oxidative stress and inflammation and disrupts the functioning of neuronal communication in critical regions of the brain, similar to those seen in aging....

A case study of potential human health impacts from petroleum coke transfer facilities.

PubMed

Dourson, Michael L; Chinkin, Lyle R; MacIntosh, David L; Finn, Jennifer A; Brown, Kathleen W; Reid, Stephen B; Martinez, Jeanelle M

2016-11-01

Petroleum coke or "petcoke" is a solid material created during petroleum refinement and is distributed via transfer facilities that may be located in densely populated areas. The health impacts from petcoke exposure to residents living in proximity to such facilities were evaluated for a petcoke transfer facilities located in Chicago, Illinois. Site-specific, margin of safety (MOS) and margin of exposure (MOE) analyses were conducted using estimated airborne and dermal exposures. The exposure assessment was based on a combined measurement and modeling program that included multiyear on-site air monitoring, air dispersion modeling, and analyses of soil and surfaces in residential areas adjacent to two petcoke transfer facilities located in industrial areas. Airborne particulate matter less than 10 microns (PM 10 ) were used as a marker for petcoke. Based on daily fence line monitoring, the average daily PM 10 concentration at the KCBX Terminals measured on-site was 32 μg/m 3 , with 89% of 24-hr average PM 10 concentrations below 50 μg/m 3 and 99% below 100 μg/m 3 . A dispersion model estimated that the emission sources at the KCBX Terminals produced peak PM 10 levels attributed to the petcoke facility at the most highly impacted residence of 11 μg/m 3 on an annual average basis and 54 μg/m 3 on 24-hr average basis. Chemical indicators of petcoke in soil and surface samples collected from residential neighborhoods adjacent to the facilities were equivalent to levels in corresponding samples collected at reference locations elsewhere in Chicago, a finding that is consistent with limited potential for off-site exposure indicated by the fence line monitoring and air dispersion modeling. The MOE based upon dispersion model estimates ranged from 800 to 900 for potential inhalation, the primary route of concern for particulate matter. This indicates a low likelihood of adverse health effects in the surrounding community. Implications: Handling of petroleum coke at bulk material transfer facilities has been identified as a concern for the public health of surrounding populations. The current assessment, based on measurements and modeling of two facilities located in a densely populated urban area, indicates that petcoke transport and accumulation in off-site locations is minimal. In addition, estimated human exposures, if any, are well below levels that could be anticipated to produce adverse health effects in the general population.

Potential Occupational Exposures and Health Risks Associated with Biomass-Based Power Generation.

PubMed

Rohr, Annette C; Campleman, Sharan L; Long, Christopher M; Peterson, Michael K; Weatherstone, Susan; Quick, Will; Lewis, Ari

2015-07-22

Biomass is increasingly being used for power generation; however, assessment of potential occupational health and safety (OH&S) concerns related to usage of biomass fuels in combustion-based generation remains limited. We reviewed the available literature on known and potential OH&S issues associated with biomass-based fuel usage for electricity generation at the utility scale. We considered three potential exposure scenarios--pre-combustion exposure to material associated with the fuel, exposure to combustion products, and post-combustion exposure to ash and residues. Testing of dust, fungal and bacterial levels at two power stations was also undertaken. Results indicated that dust concentrations within biomass plants can be extremely variable, with peak levels in some areas exceeding occupational exposure limits for wood dust and general inhalable dust. Fungal spore types, identified as common environmental species, were higher than in outdoor air. Our review suggests that pre-combustion risks, including bioaerosols and biogenic organics, should be considered further. Combustion and post-combustion risks appear similar to current fossil-based combustion. In light of limited available information, additional studies at power plants utilizing a variety of technologies and biomass fuels are recommended.

Potential Occupational Exposures and Health Risks Associated with Biomass-Based Power Generation

PubMed Central

Rohr, Annette C.; Campleman, Sharan L.; Long, Christopher M.; Peterson, Michael K.; Weatherstone, Susan; Quick, Will; Lewis, Ari

2015-01-01

Biomass is increasingly being used for power generation; however, assessment of potential occupational health and safety (OH&S) concerns related to usage of biomass fuels in combustion-based generation remains limited. We reviewed the available literature on known and potential OH&S issues associated with biomass-based fuel usage for electricity generation at the utility scale. We considered three potential exposure scenarios—pre-combustion exposure to material associated with the fuel, exposure to combustion products, and post-combustion exposure to ash and residues. Testing of dust, fungal and bacterial levels at two power stations was also undertaken. Results indicated that dust concentrations within biomass plants can be extremely variable, with peak levels in some areas exceeding occupational exposure limits for wood dust and general inhalable dust. Fungal spore types, identified as common environmental species, were higher than in outdoor air. Our review suggests that pre-combustion risks, including bioaerosols and biogenic organics, should be considered further. Combustion and post-combustion risks appear similar to current fossil-based combustion. In light of limited available information, additional studies at power plants utilizing a variety of technologies and biomass fuels are recommended. PMID:26206568

Occupational risk factors for urothelial carcinoma: agent-specific results from a case-control study in Germany. MURC Study Group. Multicenter Urothelial and Renal Cancer.

PubMed

Pesch, B; Haerting, J; Ranft, U; Klimpel, A; Oelschlägel, B; Schill, W

2000-04-01

This multicentre population-based case-control study was conducted to estimate the urothelial cancer risk for occupational exposure to aromatic amines, polycyclic aromatic hydrocarbons (PAH), and chlorinated hydrocarbons besides other suspected risk factors. In a population-based multicentre study, 1035 incident urothelial cancer cases and 4298 controls matched for region, sex, and age were interviewed between 1991 and 1995 for their occupational history and lifestyle habits. Exposure to the agents under study was self-assessed as well as expert-rated with two job-exposure matrices and a job task-exposure matrix. Conditional logistic regression was used to calculate smoking adjusted odds ratios (OR) and to control for study centre and age. Urothelial cancer risk following exposure to aromatic amines was only slightly elevated. Among males, substantial exposures to PAH as well as to chlorinated solvents and their corresponding occupational settings were associated with significantly elevated risks after adjustment for smoking (PAH exposure, assessed with a job-exposure matrix: OR = 1.6, 95% CI: 1.1-2.3, exposure to chlorinated solvents, assessed with a job task-exposure matrix: OR = 1.8, 95% CI: 1.2-2.6). Metal degreasing showed an elevated urothelial cancer risk among males (OR = 2.3, 95% CI: 1.4-3.8). In females also, exposure to chlorinated solvents indicated a urothelial cancer risk. Because of small numbers the risk evaluation for females should be treated with caution. Occupational exposure to aromatic amines could not be shown to be as strong a risk factor for urothelial carcinomas as in the past. A possible explanation for this finding is the reduction in exposure over the last 50 years. Our results strengthen the evidence that PAH may have a carcinogenic potential for the urothelium. Furthermore, our results indicate a urothelial cancer risk for the use of chlorinated solvents.

The Use of Carbonaceous Particle Exposure Metrics in Health Impact Calculations

PubMed Central

Olstrup, Henrik; Johansson, Christer; Forsberg, Bertil

2016-01-01

Combustion-related carbonaceous particles seem to be a better indicator of adverse health effects compared to PM2.5 and PM10. Historical studies are based on black smoke (BS), but more recent studies use absorbance (Abs), black carbon (BC) or elemental carbon (EC) as exposure indicators. To estimate health risks based on BS, we review the literature regarding the relationship between Abs, BS, BC and EC. We also discuss the uncertainties associated with the comparison of relative risks (RRs) based on these conversions. EC is reported to represent a proportion between 5.2% and 27% of BS with a mean value of 12%. Correlations of different metrics at one particular site are higher than when different sites are compared. Comparing all traffic, urban and rural sites, there is no systematic site dependence, indicating that other properties of the particles or errors affect the measurements and obscure the results. It is shown that the estimated daily mortality associated with short-term levels of EC is in the same range as PM10, but this is highly dependent on the EC to BS relationship that is used. RRs for all-cause mortality associated with short-term exposure to PM10 seem to be higher at sites with higher EC concentrations, but more data are needed to verify this. PMID:26927139

Radiation exposure risks to nuclear well loggers.

PubMed

Fujimoto, K; Wilson, J A; Ashmore, J P

1985-04-01

This report is based on statistical data from the Canadian National Dose Registry (As82) and information obtained from visits to 1 supplier and 9 oil-well service companies in the Province of Alberta. The companies are representative of most in this industry and provide services at the well head from logging, perforating and fracturing to cementing and tracer work. The information obtained indicates that typical exposures can account for an average dose of 1 to 2 mSv/y. The observations of well-logging procedures revealed a number of potentially hazardous situations which could lead to unnecessary exposure and based upon these, several recommendations are included.

Essential Indicators Identifying Chronic Inorganic Mercury Intoxication: Pooled Analysis across Multiple Cross-Sectional Studies

PubMed Central

Doering, Stefan

2016-01-01

Background The continuous exposure to inorganic mercury vapour in artisanal small-scale gold mining (ASGM) areas leads to chronic health problems. It is therefore essential to have a quick, but reliable risk assessing tool to diagnose chronic inorganic mercury intoxication. This study re-evaluates the state-of-the-art toolkit to diagnose chronic inorganic mercury intoxication by analysing data from multiple pooled cross-sectional studies. The primary research question aims to reduce the currently used set of indicators without affecting essentially the capability to diagnose chronic inorganic mercury intoxication. In addition, a sensitivity analysis is performed on established biomonitoring exposure limits for mercury in blood, hair, urine and urine adjusted by creatinine, where the biomonitoring exposure limits are compared to thresholds most associated with chronic inorganic mercury intoxication in artisanal small-scale gold mining. Methods Health data from miners and community members in Indonesia, Tanzania and Zimbabwe were obtained as part of the Global Mercury Project and pooled into one dataset together with their biomarkers mercury in urine, blood and hair. The individual prognostic impact of the indicators on the diagnosis of mercury intoxication is quantified using logistic regression models. The selection is performed by a stepwise forward/backward selection. Different models are compared based on the Bayesian information criterion (BIC) and Cohen`s kappa is used to evaluate the level of agreement between the diagnosis of mercury intoxication based on the currently used set of indicators and the result based on our reduced set of indicators. The sensitivity analysis of biomarker exposure limits of mercury is based on a sequence of chi square tests. Results The variable selection in logistic regression reduced the number of medical indicators from thirteen to ten in addition to the biomarkers. The estimated level of agreement using ten of thirteen medical indicators and all four biomarkers to diagnose chronic inorganic mercury intoxication yields a Cohen`s Kappa of 0.87. While in an additional stepwise selection the biomarker blood was not selected, the level of agreement based on ten medical indicators and only the three biomarkers urine, urine/creatinine and hair reduced Cohen`s Kappa to 0.46. The optimal cut-point for the biomarkers blood, hair, urine and urine/creatinine were estimated at 11. 6 μg/l, 3.84 μg/g, 24.4 μg/l and 4.26 μg/g, respectively. Conclusion The results show that a reduction down to only ten indicators still allows a reliable diagnosis of chronic inorganic mercury intoxication. This reduction of indicators will simplify health assessments in artisanal small-scale gold mining areas. PMID:27575533

Extricating Sex and Gender in Air Pollution Research: A Community-Based Study on Cardinal Symptoms of Exposure

PubMed Central

Oiamo, Tor H.; Luginaah, Isaac N.

2013-01-01

This study investigated sex and gender differences in cardinal symptoms of exposure to a mixture of ambient pollutants. A cross sectional population-based study design was utilized in Sarnia, ON, Canada. Stratified random sampling in census tracts of residents aged 18 and over recruited 804 respondents. Respondents completed a community health survey of chronic disease, general health, and socioeconomic indicators. Residential concentrations of NO2, SO2, benzene, toluene, ethylbenzene and o/m/p-xylene were estimated by land use regression on data collected through environmental monitoring. Classification and Regression Tree (CART) analysis was used to identify variables that interacted with sex and cardinal symptoms of exposure, and a series of logistic regression models were built to predict the reporting of five or more cardinal symptoms (5+ CS). Without controlling for confounders, higher pollution ranks increased the odds ratio (OR) of reporting 5+ CS by 28% (p < 0.01; Confidence Interval (CI): 1.07–1.54). Females were 1.52 (p < 0.05; CI: 1.03–2.26) times more likely more likely to report 5+ CS after controlling for income, age and chronic diseases. The CART analysis showed that allergies and occupational exposure classified the sample into the most homogenous groups of males and females. The likelihood of reporting 5+ CS among females was higher after stratifying the sample based on occupational exposure. However, stratifying by allergic disease resulted in no significant sex difference in symptom reporting. The results confirmed previous research that found pre-existing health conditions to increase susceptibility to ambient air pollution, but additionally indicated that stronger effects on females is partly due to autoimmune disorders. Furthermore, gender differences in occupational exposure confound the effect size of exposure in studies based on residential levels of air pollution. PMID:23975108

Effects of exposure, diet, and thermoregulation on fecal glucocorticoid measures in wild bears.

PubMed

Stetz, Jeff; Hunt, Kathleen; Kendall, Katherine C; Wasser, Samuel K

2013-01-01

We examined fecal glucocorticoid (fGC) measures of nutrition and thermoregulatory demands on wild bears in Glacier National Park, Montana, and assessed how these measures changed in samples left in the field. Both ambient temperature and exposure can impact thermoregulation and sample degradation. Bear diets vary markedly with season, affecting body condition and thus fGC. We collected fecal samples during September and October, 2001, when ambient temperatures ranged from 30°C to -5°C. We collected half of each sample immediately and left the other half in its original location for 1-28 days. We used generalized linear models (GLM) to first predict fGC concentrations in fresh samples based on proxies of nutrition, ambient temperature, thermal exposure, and precipitation. These same covariates were then used to predict degradation-based differences in fGC concentrations between the paired sample halves. Variation in fGC was predicted by diet, Julian date, aspect, and the interaction between Julian date and aspect in both fresh and exposed samples. Cumulative precipitation was also a significant predictor of fGC concentrations in the exposed samples, independent of time, indicating that precipitation contributes to sample degradation but not enough to mask effects of other environmental factors on fGC concentrations. Differences between sample halves were only predicted by cumulative precipitation and exposure time; cumulative precipitation decreased, whereas exposure time increased, fGC concentrations in the exposed sample halves. Results indicate that fGC can provide reliable indices of nutrition and thermoregulatory demands in bears and that sample degradation impacts on these relations are minimal and can be virtually eliminated by controlling for cumulative precipitation over the estimated exposure times.

Effects of Exposure, Diet, and Thermoregulation on Fecal Glucocorticoid Measures in Wild Bears

PubMed Central

Stetz, Jeff; Hunt, Kathleen; Kendall, Katherine C.; Wasser, Samuel K.

2013-01-01

We examined fecal glucocorticoid (fGC) measures of nutrition and thermoregulatory demands on wild bears in Glacier National Park, Montana, and assessed how these measures changed in samples left in the field. Both ambient temperature and exposure can impact thermoregulation and sample degradation. Bear diets vary markedly with season, affecting body condition and thus fGC. We collected fecal samples during September and October, 2001, when ambient temperatures ranged from 30°C to −5°C. We collected half of each sample immediately and left the other half in its original location for 1–28 days. We used generalized linear models (GLM) to first predict fGC concentrations in fresh samples based on proxies of nutrition, ambient temperature, thermal exposure, and precipitation. These same covariates were then used to predict degradation-based differences in fGC concentrations between the paired sample halves. Variation in fGC was predicted by diet, Julian date, aspect, and the interaction between Julian date and aspect in both fresh and exposed samples. Cumulative precipitation was also a significant predictor of fGC concentrations in the exposed samples, independent of time, indicating that precipitation contributes to sample degradation but not enough to mask effects of other environmental factors on fGC concentrations. Differences between sample halves were only predicted by cumulative precipitation and exposure time; cumulative precipitation decreased, whereas exposure time increased, fGC concentrations in the exposed sample halves. Results indicate that fGC can provide reliable indices of nutrition and thermoregulatory demands in bears and that sample degradation impacts on these relations are minimal and can be virtually eliminated by controlling for cumulative precipitation over the estimated exposure times. PMID:23457488

Bilirubin-a potential marker of drug exposure in atazanavir-based antiretroviral therapy.

PubMed

Rekić, Dinko; Clewe, Oskar; Röshammar, Daniel; Flamholc, Leo; Sönnerborg, Anders; Ormaasen, Vidar; Gisslén, Magnus; Abelö, Angela; Ashton, Michael

2011-12-01

The objective of this work was to examine the atazanavir-bilirubin relationship using a population-based approach and to assess the possible application of bilirubin as a readily available marker of atazanavir exposure. A model of atazanavir exposure and its concentration-dependent effect on bilirubin levels was developed based on 200 atazanavir and 361 bilirubin samples from 82 patients receiving atazanavir in the NORTHIV trial. The pharmacokinetics was adequately described by a one-compartment model with first-order absorption and lag-time. The maximum inhibition of bilirubin elimination rate constant (I(max)) was estimated at 91% (95% CI, 87-94) and the atazanavir concentration resulting in half of I(max) (IC50) was 0.30 μmol/L (95% CI, 0.24-0.37). At an atazanavir/ritonavir dose of 300/100 mg given once daily, the bilirubin half-life was on average increased from 1.6 to 8.1 h. A nomogram, which can be used to indicate suboptimal atazanavir exposure and non-adherence, was constructed based on model simulations.

Relative effects of pre- and posteruption water fluoride on caries experience of permanent first molars.

PubMed

Singh, K A; Spencer, A John; Armfield, J M

2003-01-01

Previous studies have attributed the caries-preventive effects of preeruption (PRE) and posteruption (POST) exposure to fluoridated water based on data collected before and after the commencement or discontinuation of water fluoridation. This study aims to determine the relative pre- and posteruption exposure effects of fluoridated water on caries experience of 6-15-year-old Australian children based on individual residential histories. Parental questionnaires covering residential history of participants were linked to their oral examinations conducted between June 1991 and May 1992 by the School Dental Services of South Australia and Queensland. Percentage of lifetime exposed to optimally fluoridated water PRE and POST was calculated with respect to the eruption age for first permanent molars. Combined pre- and posteruption categories were created to test PRE against POST exposure: PRE & POST = 0, PRE < POST, PRE = POST in the range 0-90 percent of lifetime exposure, PRE > POST, and PRE & POST > or = 90 percent lifetime exposure. These categories were used as indicator variables with PRE and POST = 0 as reference in an analysis of first permanent molar DMFS scores. The linear regression model controlled for important potential confounders. Participation rates were 69.7 percent in South Australia and 55.6 percent in Queensland with 9,690 and 10,195 participants, respectively. Pre- and posteruption exposures were strongly correlated (r =. 74; P < .01). Compared to the reference, the categories PRE > POST, PRE = POSTin the range 0-90 percent, and PRE and POST > or = 90 percent showed significantly lower caries levels. The findings indicated that preeruption exposure was required for a caries-preventive effect and that exposure after eruption alone did not lower caries levels significantly. However, the maximum caries-preventive effects of fluoridated water were achieved by high pre- and posteruption exposure.

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

PubMed

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

2015-07-01

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

The effects of socioeconomic status and indices of physical environment on reduced birth weight and preterm births in Eastern Massachusetts

PubMed Central

Zeka, Ariana; Melly, Steve J; Schwartz, Joel

2008-01-01

Background Air pollution and social characteristics have been shown to affect indicators of health. While use of spatial methods to estimate exposure to air pollution has increased the power to detect effects, questions have been raised about potential for confounding by social factors. Methods A study of singleton births in Eastern Massachusetts was conducted between 1996 and 2002 to examine the association between indicators of traffic, land use, individual and area-based socioeconomic measures (SEM), and birth outcomes (birth weight, small for gestational age and preterm births), in a two-level hierarchical model. Results We found effects of both individual (education, race, prenatal care index) and area-based (median household income) SEM with all birth outcomes. The associations for traffic and land use variables were mainly seen with birth weight, with an exception for an effect of cumulative traffic density on small for gestational age. Race/ethnicity of mother was an important predictor of birth outcomes and a strong confounder for both area-based SEM and indices of physical environment. The effects of traffic and land use differed by level of education and median household income. Conclusion Overall, the findings of the study suggested greater likelihood of reduced birth weight and preterm births among the more socially disadvantaged, and a greater risk of reduced birth weight associated with traffic exposures. Results revealed the importance of controlling simultaneously for SEM and environmental exposures as the way to better understand determinants of health. PMID:19032747

Influence of mobile phone traffic on base station exposure of the general public.

PubMed

Joseph, Wout; Verloock, Leen

2010-11-01

The influence of mobile phone traffic on temporal radiofrequency exposure due to base stations during 7 d is compared for five different sites with Erlang data (representing average mobile phone traffic intensity during a period of time). The time periods of high exposure and high traffic during a day are compared and good agreement is obtained. The minimal required measurement periods to obtain accurate estimates for maximal and average long-period exposure (7 d) are determined. It is shown that these periods may be very long, indicating the necessity of new methodologies to estimate maximal and average exposure from short-period measurement data. Therefore, a new method to calculate the fields at a time instant from fields at another time instant using normalized Erlang values is proposed. This enables the estimation of maximal and average exposure during a week from short-period measurements using only Erlang data and avoids the necessity of long measurement times.

Cognitive and emotional alterations in periadolescent mice exposed to 2 g hypergravity field.

PubMed

Francia, Nadia; Santucci, Daniela; Chiarotti, Flavia; Alleva, Enrico

2004-12-15

The development of the nervous system is a dynamic process where epigenetic factors play a fundamental role. Both ground-based and space research indicate that exposure to an altered gravitational environment affects rodent neurobehavioral profile and stage of development as well as duration of exposure appear to be critical for the observed effects. The behavioral profile of adolescent (28-day-old) male and female CD-1 mice upon acute 2 g exposure was characterized and emotional/anxiety responses (plus-maze), as well as spatial learning performance (Morris water-maze), were assessed respectively 24 and 48 h after hypergravity exposure. Behavioral observation indicated a transient mild sickness associated with hypergravity, with a decrease in spontaneous activity. Rotation per se induced an increase in emotional/anxious responses and a deterioration of spatial learning acquisition, while hypergravity specifically improved flexibility of spatial orientation.

Handling of thermal paper: Implications for dermal exposure to bisphenol A and its alternatives

PubMed Central

Bernier, Meghan R.

2017-01-01

Bisphenol A (BPA) is an endocrine disrupting chemical used in a wide range of consumer products including photoactive dyes used in thermal paper. Recent studies have shown that dermal absorption of BPA can occur when handling these papers. Yet, regulatory agencies have largely dismissed thermal paper as a major source of BPA exposure. Exposure estimates provided by agencies such as the European Food Safety Authority (EFSA) are based on assumptions about how humans interact with this material, stating that ‘typical’ exposures for adults involve only one handling per day for short periods of time (<1 minute), with limited exposure surfaces (three fingertips). The objective of this study was to determine how individuals handle thermal paper in one common setting: a cafeteria providing short-order meals. We observed thermal paper handling in a college-aged population (n = 698 subjects) at the University of Massachusetts’ dining facility. We find that in this setting, individuals handle receipts for an average of 11.5 min, that >30% of individuals hold thermal paper with more than three fingertips, and >60% allow the paper to touch their palm. Only 11% of the participants we observed were consistent with the EFSA model for time of contact and dermal surface area. Mathematical modeling based on handling times we measured and previously published transfer coefficients, concentrations of BPA in paper, and absorption factors indicate the most conservative estimated intake from handling thermal paper in this population is 51.1 ng/kg/day, similar to EFSA’s estimates of 59 ng/kg/day from dermal exposures. Less conservative estimates, using published data on concentrations in thermal paper and transfer rates to skin, indicate that exposures are likely significantly higher. Based on our observational data, we propose that the current models for estimating dermal BPA exposures are not consistent with normal human behavior and should be reevaluated. PMID:28570582

Handling of thermal paper: Implications for dermal exposure to bisphenol A and its alternatives.

PubMed

Bernier, Meghan R; Vandenberg, Laura N

2017-01-01

Bisphenol A (BPA) is an endocrine disrupting chemical used in a wide range of consumer products including photoactive dyes used in thermal paper. Recent studies have shown that dermal absorption of BPA can occur when handling these papers. Yet, regulatory agencies have largely dismissed thermal paper as a major source of BPA exposure. Exposure estimates provided by agencies such as the European Food Safety Authority (EFSA) are based on assumptions about how humans interact with this material, stating that 'typical' exposures for adults involve only one handling per day for short periods of time (<1 minute), with limited exposure surfaces (three fingertips). The objective of this study was to determine how individuals handle thermal paper in one common setting: a cafeteria providing short-order meals. We observed thermal paper handling in a college-aged population (n = 698 subjects) at the University of Massachusetts' dining facility. We find that in this setting, individuals handle receipts for an average of 11.5 min, that >30% of individuals hold thermal paper with more than three fingertips, and >60% allow the paper to touch their palm. Only 11% of the participants we observed were consistent with the EFSA model for time of contact and dermal surface area. Mathematical modeling based on handling times we measured and previously published transfer coefficients, concentrations of BPA in paper, and absorption factors indicate the most conservative estimated intake from handling thermal paper in this population is 51.1 ng/kg/day, similar to EFSA's estimates of 59 ng/kg/day from dermal exposures. Less conservative estimates, using published data on concentrations in thermal paper and transfer rates to skin, indicate that exposures are likely significantly higher. Based on our observational data, we propose that the current models for estimating dermal BPA exposures are not consistent with normal human behavior and should be reevaluated.

Use of Markov Chain Monte Carlo analysis with a physiologically-based pharmacokinetic model of methylmercury to estimate exposures in US women of childbearing age.

PubMed

Allen, Bruce C; Hack, C Eric; Clewell, Harvey J

2007-08-01

A Bayesian approach, implemented using Markov Chain Monte Carlo (MCMC) analysis, was applied with a physiologically-based pharmacokinetic (PBPK) model of methylmercury (MeHg) to evaluate the variability of MeHg exposure in women of childbearing age in the U.S. population. The analysis made use of the newly available National Health and Nutrition Survey (NHANES) blood and hair mercury concentration data for women of age 16-49 years (sample size, 1,582). Bayesian analysis was performed to estimate the population variability in MeHg exposure (daily ingestion rate) implied by the variation in blood and hair concentrations of mercury in the NHANES database. The measured variability in the NHANES blood and hair data represents the result of a process that includes interindividual variation in exposure to MeHg and interindividual variation in the pharmacokinetics (distribution, clearance) of MeHg. The PBPK model includes a number of pharmacokinetic parameters (e.g., tissue volumes, partition coefficients, rate constants for metabolism and elimination) that can vary from individual to individual within the subpopulation of interest. Using MCMC analysis, it was possible to combine prior distributions of the PBPK model parameters with the NHANES blood and hair data, as well as with kinetic data from controlled human exposures to MeHg, to derive posterior distributions that refine the estimates of both the population exposure distribution and the pharmacokinetic parameters. In general, based on the populations surveyed by NHANES, the results of the MCMC analysis indicate that a small fraction, less than 1%, of the U.S. population of women of childbearing age may have mercury exposures greater than the EPA RfD for MeHg of 0.1 microg/kg/day, and that there are few, if any, exposures greater than the ATSDR MRL of 0.3 microg/kg/day. The analysis also indicates that typical exposures may be greater than previously estimated from food consumption surveys, but that the variability in exposure within the population of U.S. women of childbearing age may be less than previously assumed.

An exposure-based, ecology-driven framework for selection of indicator species for insecticide risk assessment

USDA-ARS?s Scientific Manuscript database

In the current “tiered” paradigm for evaluating risks of insecticidal products, one of the first decisions that must be made is the selection of indicator species to be used in toxicity assays. However, as yet, no formal system has been developed to determine whether proposed indicator species are r...

A tissue dose-based comparative exposure assessment of manganese using physiologically based pharmacokinetic modeling—The importance of homeostatic control for an essential metal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gentry, P. Robinan, E-mail: rgentry@ramboll.com

A physiologically-based pharmacokinetic (PBPK) model (Schroeter et al., 2011) was applied to simulate target tissue manganese (Mn) concentrations following occupational and environmental exposures. These estimates of target tissue Mn concentrations were compared to determine margins of safety (MOS) and to evaluate the biological relevance of applying safety factors to derive acceptable Mn air concentrations. Mn blood concentrations measured in occupational studies permitted verification of the human PBPK models, increasing confidence in the resulting estimates. Mn exposure was determined based on measured ambient air Mn concentrations and dietary data in Canada and the United States (US). Incorporating dietary and inhalation exposuresmore » into the models indicated that increases in target tissue concentrations above endogenous levels only begin to occur when humans are exposed to levels of Mn in ambient air (i.e. > 10 μg/m{sup 3}) that are far higher than those currently measured in Canada or the US. A MOS greater than three orders of magnitude was observed, indicating that current Mn air concentrations are far below concentrations that would be required to produce the target tissue Mn concentrations associated with subclinical neurological effects. This application of PBPK modeling for an essential element clearly demonstrates that the conventional application of default factors to “convert” an occupational exposure to an equivalent continuous environmental exposure, followed by the application of safety factors, is not appropriate in the case of Mn. PBPK modeling demonstrates that the relationship between ambient Mn exposures and dose-to-target tissue is not linear due to normal tissue background levels and homeostatic controls. - Highlights: • Manganese is an essential nutrient, adding complexity to its risk assessment. • Nonlinearities in biological processes are important for manganese risk assessment. • A PBPK model was used to estimate target tissue concentrations of manganese. • An MOS approach also considered target tissue concentrations for ambient exposures. • Relationships between ambient Mn exposures and dose-to-target tissue are not linear.« less

Factors associated with self-reported health: implications for ...

EPA Pesticide Factsheets

BACKGROUND: Advocates for environmental justice, local, state, and national public health officials, exposure scientists, need broad-based heath indices to identify vulnerable communities. Longitudinal studies show that perception of current health status predicts subsequent mortality, suggesting that self-reported health (SRH) may be useful in screening-level community assessments. This paper evaluates whether SRH is an appropriate surrogate indicator of health status by evaluating relationships between SRH and sociodemographic, lifestyle, and health care factors as well as serological indicators of nutrition, health risk, and environmental exposures.METHODS: Data were combined from the 2003-2006 National Health and Nutrition Examination Surveys for 1372 nonsmoking 20-50 year olds. Ordinal and binary logistic regression was used to estimate odds ratios and 95 % confidence intervals of reporting poorer health based on measures of nutrition, health condition, environmental contaminants, and sociodemographic, health care, and lifestyle factors.RESULTS: Poorer SRH was associated with several serological measures of nutrition, health condition, and biomarkers of toluene, cadmium, lead, and mercury exposure. Race/ethnicity, income, education, access to health care, food security, exercise, poor mental and physical health, prescription drug use, and multiple health outcome measures (e.g., diabetes, thyroid problems, asthma) were also associated with poorer SRH.CONCLUS

Occupational exposure to petroleum-based and oxygenated solvents and hypopharyngeal and laryngeal cancer in France: the ICARE study.

PubMed

Barul, Christine; Carton, Matthieu; Radoï, Loredana; Menvielle, Gwenn; Pilorget, Corinne; Bara, Simona; Stücker, Isabelle; Luce, Danièle

2018-04-05

To examine associations between occupational exposure to petroleum-based and oxygenated solvents and the risk of hypopharyngeal and laryngeal cancer. ICARE is a large, frequency-matched population-based case-control study conducted in France. Lifetime occupational history, tobacco smoking and alcohol consumption were collected. Analyses were restricted to men and included 383 cases of hypopharyngeal cancer, 454 cases of laryngeal cancer, and 2780 controls. Job-exposure matrices were used to assess exposure to five petroleum-based solvents (benzene; gasoline; white spirits; diesel, fuels and kerosene; special petroleum products) and to five oxygenated solvents (alcohols; ketones and esters; ethylene glycol; diethyl ether; tetrahydrofuran). Odds ratios (ORs) adjusted for smoking, alcohol drinking and other potential confounders and 95% confidence intervals (CI) were estimated with unconditional logistic models. No significant association was found between hypopharyngeal or laryngeal cancer risk and exposure to the solvents under study. Non-significantly elevated risks of hypopharyngeal cancer were found in men exposed to high cumulative levels of white spirits (OR = 1.46; 95% CI: 0.88-2.43) and tetrahydrofuran (OR = 2.63; 95CI%: 0.55-12.65), with some indication of a dose-response relationship (p for trend: 0.09 and 0.07 respectively). This study provides weak evidence for an association between hypopharyngeal cancer and exposure to white spirits and tetrahydrofuran, and overall does not suggest a substantial role of exposure to petroleum-based or oxygenated solvents in hypopharyngeal or laryngeal cancer risk.

Task-based exposure assessment of nanoparticles in the workplace

NASA Astrophysics Data System (ADS)

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

2012-09-01

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

A population-based exposure assessment methodology for carbon monoxide: Development of a carbon monoxide passive sampler and occupational dosimeter

DOE Office of Scientific and Technical Information (OSTI.GOV)

Apte, Michael G.

Two devices, an occupational carbon monoxide (CO) dosimeter (LOCD), and an indoor air quality (IAQ) passive sampler were developed for use in population-based CO exposure assessment studies. CO exposure is a serious public health problem in the U.S., causing both morbidity and mortality (lifetime mortality risk approximately 10{sup -4}). Sparse data from population-based CO exposure assessments indicate that approximately 10% of the U.S. population is exposed to CO above the national ambient air quality standard. No CO exposure measurement technology is presently available for affordable population-based CO exposure assessment studies. The LOCD and IAQ Passive Sampler were tested in themore » laboratory and field. The palladium-molybdenum based CO sensor was designed into a compact diffusion tube sampler that can be worn. Time-weighted-average (TWA) CO exposure of the device is quantified by a simple spectrophotometric measurement. The LOCD and IAQ Passive Sampler were tested over an exposure range of 40 to 700 ppm-hours and 200 to 4200 ppm-hours, respectively. Both devices were capable of measuring precisely (relative standard deviation <20%), with low bias (<10%). The LOCD was screened for interferences by temperature, humidity, and organic and inorganic gases. Temperature effects were small in the range of 10°C to 30°C. Humidity effects were low between 20% and 90% RH. Ethylene (200 ppm) caused a positive interference and nitric oxide (50 ppm) caused a negative response without the presence of CO but not with CO.« less

Glucocorticoids enhance extinction-based psychotherapy

PubMed Central

de Quervain, Dominique J.-F.; Bentz, Dorothée; Michael, Tanja; Bolt, Olivia C.; Wiederhold, Brenda K.; Margraf, Jürgen; Wilhelm, Frank H.

2011-01-01

Behavioral exposure therapy of anxiety disorders is believed to rely on fear extinction. Because preclinical studies have shown that glucocorticoids can promote extinction processes, we aimed at investigating whether the administration of these hormones might be useful in enhancing exposure therapy. In a randomized, double-blind, placebo-controlled study, 40 patients with specific phobia for heights were treated with three sessions of exposure therapy using virtual reality exposure to heights. Cortisol (20 mg) or placebo was administered orally 1 h before each of the treatment sessions. Subjects returned for a posttreatment assessment 3–5 d after the last treatment session and for a follow-up assessment after 1 mo. Adding cortisol to exposure therapy resulted in a significantly greater reduction in fear of heights as measured with the acrophobia questionnaire (AQ) both at posttreatment and at follow-up, compared with placebo. Furthermore, subjects receiving cortisol showed a significantly greater reduction in acute anxiety during virtual exposure to a phobic situation at posttreatment and a significantly smaller exposure-induced increase in skin conductance level at follow-up. The present findings indicate that the administration of cortisol can enhance extinction-based psychotherapy. PMID:21444799

Strength through adversity: Moderate lifetime stress exposure is associated with psychological resilience in breast cancer survivors

PubMed Central

Dooley, Larissa N.; Slavich, George M.; Moreno, Patricia I.; Bower, Julienne E.

2017-01-01

Stress research typically emphasizes the toxic effects of stress, but recent evidence has suggested that stress exposure, in moderation, can facilitate resilience. To test whether moderate stress exposure promotes psychological resilience to cancer, we examined the relationship between lifetime stress exposure prior to cancer diagnosis and postdiagnosis psychological functioning among 122 breast cancer survivors. Lifetime acute and chronic stress was assessed using an interview-based measure, and psychological functioning was assessed using measures of cancer-related intrusive thoughts and positive and negative affect. Results indicated that acute stress exposure was associated with cancer-related intrusive thoughts in a quadratic fashion (p = .016), such that participants with moderate acute stress reported fewer intrusive thoughts compared to those with low or high acute stress. Similarly, a quadratic relationship emerged between acute stress exposure and positive affect (p = .009), such that individuals with moderate acute stress reported the highest levels of positive affect. In contrast, acute and chronic stress were related to negative affect in a positive, linear fashion (ps < .05). In conclusion, moderate stress exposure was associated with indicators of psychological resilience among breast cancer survivors, supporting stress exposure as a key factor influencing adjustment to breast cancer and providing evidence for stress-induced resilience in a novel population. PMID:28052491

Pilot task-based assessment of noise levels among firefighters.

PubMed

Neitzel, Rl; Hong, O; Quinlan, P; Hulea, R

2013-11-01

Over one million American firefighters are routinely exposed to various occupational hazards agents. While efforts have been made to identify and reduce some causes of injuries and illnesses among firefighters, relatively little has been done to evaluate and understand occupational noise exposures in this group. The purpose of this pilot study was to apply a task-based noise exposure assessment methodology to firefighting operations to evaluate potential noise exposure sources, and to use collected task-based noise levels to create noise exposure estimates for evaluation of risk of noise-induced hearing loss by comparison to the 8-hr and 24-hr recommended exposure limits (RELs) for noise of 85 and 80.3 dBA, respectively. Task-based noise exposures (n=100 measurements) were measured in three different fire departments (a rural department in Southeast Michigan and suburban and urban departments in Northern California). These levels were then combined with time-at-task information collected from firefighters to estimate 8-hr noise exposures for the rural and suburban fire departments (n=6 estimates for each department). Data from 24-hr dosimetry measurements and crude self-reported activity categories from the urban fire department (n=4 measurements) were used to create 24-hr exposure estimates to evaluate the bias associated with the task-based estimates. Task-based noise levels were found to range from 82-109 dBA, with the highest levels resulting from use of saws and pneumatic chisels. Some short (e.g., 30 min) sequences of common tasks were found to result in nearly an entire allowable daily exposure. The majority of estimated 8-hr and 24-hr exposures exceeded the relevant recommended exposure limit. Predicted 24-hr exposures showed substantial imprecision in some cases, suggesting the need for increased task specificity. The results indicate potential for overexposure to noise from a variety of firefighting tasks and equipment, and suggest a need for further exposure characterization and additional hearing loss prevention efforts. Firefighters may be at risk of noise-induced hearing loss, which can affect their fitness for duty and ability to respond effectively to emergencies. The results of this study suggest that additional efforts at hearing loss prevention among firefighters are warranted.

Agent Orange exposure and prevalence of self-reported diseases in Korean Vietnam veterans.

PubMed

Yi, Sang-Wook; Ohrr, Heechoul; Hong, Jae-Seok; Yi, Jee-Jeon

2013-09-01

The aim of this study was to evaluate the association between Agent Orange exposure and self-reported diseases in Korean Vietnam veterans. A postal survey of 114 562 Vietnam veterans was conducted. The perceived exposure to Agent Orange was assessed by a 6-item questionnaire. Two proximity-based Agent Orange exposure indices were constructed using division/brigade-level and battalion/company-level unit information. Adjusted odds ratios (ORs) for age and other confounders were calculated using a logistic regression model. The prevalence of all self-reported diseases showed monotonically increasing trends as the levels of perceived self-reported exposure increased. The ORs for colon cancer (OR, 1.13), leukemia (OR, 1.56), hypertension (OR, 1.03), peripheral vasculopathy (OR, 1.07), enterocolitis (OR, 1.07), peripheral neuropathy (OR, 1.07), multiple nerve palsy (OR, 1.14), multiple sclerosis (OR, 1.24), skin diseases (OR, 1.05), psychotic diseases (OR, 1.07) and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the division/brigade-level proximity-based exposure analysis, compared to the low exposure group. The ORs for cerebral infarction (OR, 1.08), chronic bronchitis (OR, 1.05), multiple nerve palsy (OR, 1.07), multiple sclerosis (OR, 1.16), skin diseases (OR, 1.05), and lipidemia (OR, 1.05) were significantly elevated for the high exposure group in the battalion/company-level analysis. Korean Vietnam veterans with high exposure to Agent Orange experienced a higher prevalence of several self-reported chronic diseases compared to those with low exposure by proximity-based exposure assessment. The strong positive associations between perceived self-reported exposure and all self-reported diseases should be evaluated with discretion because the likelihood of reporting diseases was directly related to the perceived intensity of Agent Orange exposure.

Radiofrequency electromagnetic fields emitted from base stations of DECT cordless phones and the risk of glioma and meningioma (Interphone Study Group, Germany).

PubMed

Schüz, Joachim; Böhler, Eva; Schlehofer, Brigitte; Berg, Gabriele; Schlaefer, Klaus; Hettinger, Iris; Kunna-Grass, Katharina; Wahrendorf, Jürgen; Blettner, Maria

2006-07-01

The objective of this study was to test the hypothesis that exposure to continuous low-level radiofrequency electromagnetic fields (RF EMFs) increases the risk of glioma and meningioma. Participants in a population-based case-control study in Germany on the risk of brain tumors in relation to cellular phone use were 747 incident brain tumor cases between the ages of 30 and 69 years and 1494 matched controls. The exposure measure of this analysis was the location of a base station of a DECT (Digital Enhanced Cordless Telecommunications) cordless phone close to the bed, which was used as a proxy for continuous low-level exposure to RF EMFs during the night. Estimated odds ratios were 0.82 (95% confidence interval: 0.29-2.33) for glioma and 0.83 (0.29-2.36) for meningioma. There was also no increasing risk observed with duration of exposure to DECT cordless phone base stations. Although the study was limited due to the small number of exposed subjects, it is still a first indication that residential low-level exposure to RF EMFs may not pose a higher risk of brain tumors.

Evaluation of potential toxicity from co-exposure to three CNS depressants (toluene, ethylbenzene, and xylene) under resting and working conditions using PBPK modeling.

PubMed

Dennison, James E; Bigelow, Philip L; Mumtaz, Moiz M; Andersen, Melvin E; Dobrev, Ivan D; Yang, Raymond S H

2005-03-01

Under OSHA and American Conference of Governmental Industrial Hygienists (ACGIH) guidelines, the mixture formula (unity calculation) provides a method for evaluating exposures to mixtures of chemicals that cause similar toxicities. According to the formula, if exposures are reduced in proportion to the number of chemicals and their respective exposure limits, the overall exposure is acceptable. This approach assumes that responses are additive, which is not the case when pharmacokinetic interactions occur. To determine the validity of the additivity assumption, we performed unity calculations for a variety of exposures to toluene, ethylbenzene, and/or xylene using the concentration of each chemical in blood in the calculation instead of the inhaled concentration. The blood concentrations were predicted using a validated physiologically based pharmacokinetic (PBPK) model to allow exploration of a variety of exposure scenarios. In addition, the Occupational Safety and Health Administration and ACGIH occupational exposure limits were largely based on studies of humans or animals that were resting during exposure. The PBPK model was also used to determine the increased concentration of chemicals in the blood when employees were exercising or performing manual work. At rest, a modest overexposure occurs due to pharmacokinetic interactions when exposure is equal to levels where a unity calculation is 1.0 based on threshold limit values (TLVs). Under work load, however, internal exposure was 87%higher than provided by the TLVs. When exposures were controlled by a unity calculation based on permissible exposure limits (PELs), internal exposure was 2.9 and 4.6 times the exposures at the TLVs at rest and workload, respectively. If exposure was equal to PELs outright, internal exposure was 12.5 and 16 times the exposure at the TLVs at rest and workload, respectively. These analyses indicate the importance of (1) selecting appropriate exposure limits, (2) performing unity calculations, and (3) considering the effect of work load on internal doses, and they illustrate the utility of PBPK modeling in occupational health risk assessment.

Communicating environmental exposure results and health information in a community-based participatory research study.

PubMed

Claudio, Luz; Gilmore, Jalisa; Roy, Mohana; Brenner, Barbara

2018-06-25

Communicating results to participants is a fundamental component of community-based participatory research (CBPR). However, in environmental exposure studies this is not always practiced, partly due to ethical concerns of communicating results that have unknown clinical significance. Growing Up Healthy was a community-based participatory research study that sought to understand the relationship between environmental exposures to phthalates and early puberty in young girls. After in-depth consultation with a Community Advisory Board, study investigators provided group summary results of phthalate exposures and related health information to the parents of study participants. Parents' comprehension and knowledge of the health information provided was then assessed through questionnaires. After receiving the information from the research team, responders were able to correctly answer comprehension questions about phthalate exposures in their community, were able to identify ways to reduce exposure to phthalates, and indicated plans to do so. Questionnaires revealed that parents wanted more information on phthalates, and that children's environmental health was an important concern. We conclude that effective communication of exposure results of unknown clinical significance to participants in environmental health studies can be achieved by providing group summary results and actionable health information. Results suggest that there was an improvement in knowledge of environmental health and in risk reduction behaviors in our study population.

Exposure to oil mist and oil vapour during offshore drilling in norway, 1979-2004.

PubMed

Steinsvåg, Kjersti; Bråtveit, Magne; Moen, Bente E

2006-03-01

To describe personal exposure to airborne hydrocarbon contaminants (oil mist and oil vapour) from 1979 to 2004 in the mud-handling areas of offshore drilling facilities operating on the Norwegian continental shelf when drilling with oil-based muds. Qualitative and quantitative information was gathered during visits to companies involved in offshore oil and gas production in Norway. Monitoring reports on oil mist and oil vapour exposure covered 37 drilling facilities. Exposure data were analysed using descriptive statistics and by constructing linear mixed-effects models. Samples had been taken during the use of three generations of hydrocarbon base oils, namely diesel oils (1979-1984), low-aromatic mineral oils (1985-1997) and non-aromatic mineral oils (1998-2004). Sampling done before 1984 showed high exposure to diesel vapour (arithmetic mean, AM = 1217 mg m(-3)). When low-aromatic mineral oils were used, the exposure to oil mist and oil vapour was 4.3 and 36 mg m(-3), and the respective AMs for non-aromatic mineral oils were reduced to 0.54 and 16 mg m(-3). Downward time trends were indicated for both oil mist (6% per year) and oil vapour (8% per year) when the year of monitoring was introduced as a fixed effect in a linear mixed-effects model analysis. Rig type, technical control measures and mud temperature significantly determined exposure to oil mist. Rig type, type of base oil, viscosity of the base oil, work area, mud temperature and season significantly determined exposure to oil vapour. Major decreases in variability were found for the between-rig components. Exposure to oil mist and oil vapour declined over time in the mud-handling areas of offshore drilling facilities. Exposure levels were associated with rig type, mud temperature, technical control measures, base oil, viscosity of the base oil, work area and season.

Featured Article: Community Crime Exposure and Risk for Obesity in Preschool Children: Moderation by the Hypothalamic-Pituitary-Adrenal-Axis Response.

PubMed

Gartstein, Maria A; Seamon, Erich; Thompson, Stephanie F; Lengua, Liliana J

2018-05-01

Identification of early risk factors related to obesity is critical to preventative public health efforts. In this study, we investigated links between the Hypothalamic-Pituitary-Adrenal (HPA)-axis activity (diurnal cortisol pattern), geospatially operationalized exposure to neighborhood crime, and body mass index (BMI) for a sample of 5-year-old children. Greater community crime exposure and lower HPA-axis activity were hypothesized to contribute to higher BMI, with child HPA-axis moderating the association between crime exposure and BMI. Families residing within the boundaries of the City of Seattle (N = 114) provided information concerning demographic/psychosocial risk factors, used to calculate a Cumulative Risk Index, indicating the number of contextual adversities present. Child BMI and diurnal cortisol pattern (derived from assays of saliva samples) were examined, along with neighborhood crime indices computed with publically available information, based on participants' locations. Hierarchical multiple regression analyses, adjusted for covariates (cumulative risk, age, and sex), indicated that crime proximity made a unique contribution to child BMI, in the direction signaling an increase in the risk for obesity. Consistent with our hypothesis, a significant interaction was observed, indicative of moderation by diurnal cortisol pattern. Follow-up simple slope analyses demonstrated that crime exposure was significantly related to higher BMI for children with low-flat (blunted) diurnal cortisol patterns, where community crime and BMI were not significantly associated at higher levels of cortisol. Community crime exposure contributes to higher BMI as early as the preschool period, and blunted diurnal cortisol patterns may place children experiencing neighborhood adversity at greater risk for obesity.

Factors associated with self-reported health: implications for screening level community-based health and environmental studies

EPA Science Inventory

BACKGROUND: Advocates for environmental justice, local, state, and national public health officials, exposure scientists, need broad-based heath indices to identify vulnerable communities. Longitudinal studies show that perception of current health status predicts subsequent mort...

Skin permeability enhancement by Bacillus subtilis alkaline protease: Application to transdermal drug delivery.

PubMed

Nounou, Mohamed I; Zaghloul, Taha I; Ahmed, Nehal A; Eid, Amira A; El-Khordagui, Labiba K

2017-08-30

Enzymes may offer great potentials in topical pharmaceutical applications provided that treatment conditions are controlled for efficacy and safety. In this study, the effect of alkaline protease produced by recombinant Bacillus subtilis cells on the ex-vivo permeability of rabbit ear skin was investigated under different conditions of enzyme activity (5-60 units) and exposure time (15-60min). Data for transepidermal water loss (TEWL) and permeation of a hydrophilic dye, rhodamine B (Rb), indicated biphasic activity-dependent and exposure time-dependent skin permeability. Maximum effects were obtained at 20 proteolytic units and 30min exposure. Findings proved consistent with histopathological changes indicating progressive stratum corneum (SC) loss and disruption of the dermo-epidermal junction at 20 units and up to 30min exposure time followed by dermal hyalinization at longer exposure. This was associated with progressive loss of skin hair. Applying the identified pretreatment conditions to transdermal delivery of vardenafil in a gel base across dorsal rat skin indicated a significant increase in plasma levels at 30 and 60min with minimal histopathological changes 5days post enzyme treatment. Accordingly, the recombinant B. subtilis alkaline protease offers promise as a pharmaceutical enzyme for transdermal drug delivery bioenhancement and dermatological applications. Copyright © 2017 Elsevier B.V. All rights reserved.

Interactions between occupational exposure to extremely low frequency magnetic fields and chemicals for brain tumour risk in the INTEROCC study.

PubMed

Turner, Michelle C; Benke, Geza; Bowman, Joseph D; Figuerola, Jordi; Fleming, Sarah; Hours, Martine; Kincl, Laurel; Krewski, Daniel; McLean, Dave; Parent, Marie-Elise; Richardson, Lesley; Sadetzki, Siegal; Schlaefer, Klaus; Schlehofer, Brigitte; Schüz, Joachim; Siemiatycki, Jack; Tongeren, Martie van; Cardis, Elisabeth

2017-11-01

In absence of clear evidence regarding possible effects of occupational chemical exposures on brain tumour aetiology, it is worthwhile to explore the hypothesis that such exposures might act on brain tumour risk in interaction with occupational exposure to extremely low frequency magnetic fields (ELF). INTEROCC is a seven-country (Australia, Canada, France, Germany, Israel, New Zealand and UK), population-based, case-control study, based on the larger INTERPHONE study. Incident cases of primary glioma and meningioma were ascertained from 2000 to 2004. Job titles were coded into standard international occupational classifications and estimates of ELF and chemical exposures were assigned based on job-exposure matrices. Dichotomous indicators of cumulative ELF (≥50th vs <50th percentile, 1-4 year exposure time window) and chemical exposures (ever vs never, 5-year lag) were created. Interaction was assessed on both the additive and multiplicative scales. A total of 1939 glioma cases, 1822 meningioma cases and 5404 controls were included in the analysis, using conditional logistic regression. There was no clear evidence for interactions between ELF and any of the chemical exposures assessed for either glioma or meningioma risk. For glioma, subjects in the low ELF/metal exposed group had a lower risk than would be predicted from marginal effects. Results were similar according to different exposure time windows, to cut-points of exposure or in exposed-only analyses. There was no clear evidence for interactions between occupational ELF and chemical exposures in relation to glioma or meningioma risk observed. Further research with more refined estimates of occupational exposures is recommended. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Is ultraviolet exposure acquired at work the most important risk factor for cutaneous squamous cell carcinoma? Results of the population-based case-control study FB-181.

PubMed

Schmitt, J; Haufe, E; Trautmann, F; Schulze, H-J; Elsner, P; Drexler, H; Bauer, A; Letzel, S; John, S M; Fartasch, M; Brüning, T; Seidler, A; Dugas-Breit, S; Gina, M; Weistenhöfer, W; Bachmann, K; Bruhn, I; Lang, B M; Bonness, S; Allam, J P; Grobe, W; Stange, T; Westerhausen, S; Knuschke, P; Wittlich, M; Diepgen, T L

2018-02-01

Squamous cell carcinoma (SCC) is one of the most frequent types of cancer constituting a significant public health burden. Prevention strategies focus on limiting ultraviolet (UV) exposure during leisure time. However, the relative impact of occupational and nonoccupational UV exposure for SCC occurrence is unclear. To investigate the association between occupational and nonoccupational UV exposure for SCC in a multicentre population-based case-control study hypothesizing that high occupational UV exposure increases the risk of SCC. Consecutive patients with incident SCC (n = 632) were recruited from a German national dermatology network. Population-based controls (n = 996) without history of skin cancer were recruited from corresponding residents' registration offices and propensity score matched to cases. Lifetime UV exposure, sociodemographic and clinical characteristics were assessed by trained physicians. Occupational and nonoccupational UV exposure doses were estimated by masked investigators using established reference values. Odds ratios (ORs) and corresponding 95% confidence intervals (CIs) were assessed using conditional logistic regression adjusting for relevant confounders. Total solar UV exposure was significantly associated with increased SCC. The OR for high (> 90th percentile) vs. low (< 40th percentile) and high vs, moderate (40-59th percentile) occupational UV exposure was 1·95 (95% CI 1·19-3·18) and 2·44 (95% CI 1·47-4·06) for SCC. Adjusting for occupational UV exposure, nonoccupational UV exposure was not significantly related to SCC incidence. Dose-response relationships were observed for occupational but not for nonoccupational solar UV exposure. Solar occupational UV exposure is a major determinant of incident SCC. Our findings indicate that prevention strategies should be further expanded to the occupational setting. © 2017 British Association of Dermatologists.

Occupational exposure to magnetic fields in relation to mortality from brain cancer among electricity generation and transmission workers.

PubMed Central

Harrington, J M; McBride, D I; Sorahan, T; Paddle, G M; van Tongeren, M

1997-01-01

OBJECTIVE: To investigate whether the risks of mortality from brain cancer are related to occupational exposure to magnetic fields. METHODS: A total of 112 cases of primary brain cancer (1972-91) were identified from a cohort of 84,018 male and female employees of the (then) Central Electricity Generating Board and its privatised successor companies. Individual cumulative occupational exposures to magnetic fields were estimated by linking available computerised job history data with magnetic field measurements collected over 675 person-workshifts. Estimated exposure histories of the case workers were compared with those of 654 control workers drawn from the cohort (nested case-control study), by means of conditional logistic regression. RESULTS: For exposure assessments based on arithmetic means, the risk of mortality from brain cancer for subjects with an estimated cumulative exposure to magnetic fields of 5.4-13.4 microT.y v subjects with lower exposures (0.0-5.3 microT.y) was 1.04 (95% confidence interval (95% CI) 0.60 to 1.80). The corresponding relative risk in subjects with higher exposures (> or = 13.5 microT.y) was 0.95 (95% CI 0.54 to 1.69). There was no indication of a positive trend for cumulative exposure and risk of mortality from brain cancer either when the analysis used exposure assessments based on geometric means or when the analysis was restricted to exposures received within five years of the case diagnosis (or corresponding period for controls). CONCLUSIONS: Although the exposure categorisation was based solely on recent observations, the study findings do not support the hypothesis that the risk of brain cancer is associated with occupational exposure to magnetic fields. PMID:9072027

Characterizing distributions of surface ozone and its impact on grain production in China, Japan and South Korea: 1990 and 2020

NASA Astrophysics Data System (ADS)

Wang, Xiaoping; Mauzerall, Denise L.

Using an integrated assessment approach, we evaluate the impact that surface O 3 in East Asia had on agricultural production in 1990 and is projected to have in 2020. We also examine the effect that emission controls and the enforcement of environmental standards could have in increasing grain production in China. We find that given projected increases in O 3 concentrations in the region, East Asian countries are presently on the cusp of substantial reductions in grain production. Our conservative estimates, based on 7- and 12-h mean (M7 or M12) exposure indices, show that due to O 3 concentrations in 1990 China, Japan and South Korea lost 1-9% of their yield of wheat, rice and corn and 23-27% of their yield of soybeans, with an associated value of 1990US 3.5, 1.2 and 0.24 billion, respectively. In 2020, assuming no change in agricultural production practices and again using M7 and M12 exposure indices, grain loss due to increased levels of O 3 pollution is projected to increase to 2-16% for wheat, rice and corn and 28-35% for soybeans; the associated economic costs are expected to increase by 82%, 33%, and 67% in 2020 over 1990 for China, Japan and South Korea, respectively. For most crops, the yield losses in 1990 based on SUM06 or W126 exposure indices are lower than yield losses estimated using M7 or M12 exposure indices in China and Japan but higher in South Korea; in 2020, the yield losses based on SUM06 or W126 exposure indices are substantially higher for all crops in all three countries. This is primarily due to the nature of the cumulative indices which weight elevated values of O 3 more heavily than lower values. Chinese compliance with its ambient O 3 standard in 1990 would have had a limited effect in reducing the grain yield loss caused by O 3 exposure, resulting in only US 0.2 billion of additional grain revenues, but in 2020 compliance could reduce the yield loss by one third and lead to an increase of US$ 2.6 (M7 or M12) -27 (SUM06) billion in grain revenues. We conclude that East Asian countries may have tremendous losses of crop yields in the near future due to projected increases in O 3 concentrations. They likely could achieve substantial increases in future agricultural production through reduction of surface O 3 concentrations and/or use of O 3 resistant crop cultivars.

Ionizing radiation: future etiologic research and preventive strategies.

PubMed

Darby, S C; Inskip, P D

1995-11-01

Estimates of cancer risks following exposure to ionizing radiation traditionally have been based on the experience of populations exposed to substantial (and known) doses delivered over short periods of time. Examples include survivors of the atomic bombings at Hiroshima and Nagasaki, and persons treated with radiation for benign or malignant disease. Continued follow-up of these populations is important to determine the long-term effects of exposure in childhood, to characterize temporal patterns of excess risk for different types of cancer, and to understand better the interactions between radiation and other host and environmental factors. Most population exposure to radiation occurs at very low dose rates. For low linear energy transfer (LET) radiations, it often has been assumed that cancer risks per unit dose are lower following protracted exposure than following acute exposure. Studies of nuclear workers chronically exposed over a working lifetime provide data that can be used to test this hypothesis, and preliminary indications are that the risks per unit dose for most cancers other than leukemia are similar to those for acute exposure. However, these results are subject to considerable uncertainty, and further information on this question is needed. Residential radon is the major source of population exposure to high-LET radiation. Current estimates of the risk of lung cancer due to residential exposure to radon and radon daughters are based on the experience of miners exposed to much higher concentrations. Data indicate that lung cancer risk among miners is inversely associated with exposure rate, and also is influenced by the presence of other lung carcinogens such as arsenic in the mine environment. Further study of populations of radon-exposed miners would be informative, particularly those exposed at below-average levels. More direct evidence on the effects of residential exposure to radon also is desirable but might be difficult to come by, as risks associated with radon levels found in most homes might be too low to be quantified accurately in epidemiological studies.

Ionizing radiation: future etiologic research and preventive strategies.

PubMed Central

Darby, S C; Inskip, P D

1995-01-01

Estimates of cancer risks following exposure to ionizing radiation traditionally have been based on the experience of populations exposed to substantial (and known) doses delivered over short periods of time. Examples include survivors of the atomic bombings at Hiroshima and Nagasaki, and persons treated with radiation for benign or malignant disease. Continued follow-up of these populations is important to determine the long-term effects of exposure in childhood, to characterize temporal patterns of excess risk for different types of cancer, and to understand better the interactions between radiation and other host and environmental factors. Most population exposure to radiation occurs at very low dose rates. For low linear energy transfer (LET) radiations, it often has been assumed that cancer risks per unit dose are lower following protracted exposure than following acute exposure. Studies of nuclear workers chronically exposed over a working lifetime provide data that can be used to test this hypothesis, and preliminary indications are that the risks per unit dose for most cancers other than leukemia are similar to those for acute exposure. However, these results are subject to considerable uncertainty, and further information on this question is needed. Residential radon is the major source of population exposure to high-LET radiation. Current estimates of the risk of lung cancer due to residential exposure to radon and radon daughters are based on the experience of miners exposed to much higher concentrations. Data indicate that lung cancer risk among miners is inversely associated with exposure rate, and also is influenced by the presence of other lung carcinogens such as arsenic in the mine environment. Further study of populations of radon-exposed miners would be informative, particularly those exposed at below-average levels. More direct evidence on the effects of residential exposure to radon also is desirable but might be difficult to come by, as risks associated with radon levels found in most homes might be too low to be quantified accurately in epidemiological studies. PMID:8741792

Prediction of Fetal Darunavir Exposure by Integrating Human Ex-Vivo Placental Transfer and Physiologically Based Pharmacokinetic Modeling.

PubMed

Schalkwijk, Stein; Buaben, Aaron O; Freriksen, Jolien J M; Colbers, Angela P; Burger, David M; Greupink, Rick; Russel, Frans G M

2017-07-25

Fetal antiretroviral exposure is usually derived from the cord-to-maternal concentration ratio. This static parameter does not provide information on the pharmacokinetics in utero, limiting the assessment of a fetal exposure-effect relationship. The aim of this study was to incorporate placental transfer into a pregnancy physiologically based pharmacokinetic model to simulate and evaluate fetal darunavir exposure at term. An existing and validated pregnancy physiologically based pharmacokinetic model of maternal darunavir/ritonavir exposure was extended with a feto-placental unit. To parameterize the model, we determined maternal-to-fetal and fetal-to-maternal darunavir/ritonavir placental clearance with an ex-vivo human cotyledon perfusion model. Simulated maternal and fetal pharmacokinetic profiles were compared with observed clinical data to qualify the model for simulation. Next, population fetal pharmacokinetic profiles were simulated for different maternal darunavir/ritonavir dosing regimens. An average (±standard deviation) maternal-to-fetal cotyledon clearance of 0.91 ± 0.11 mL/min and fetal-to-maternal clearance of 1.6 ± 0.3 mL/min was determined (n = 6 perfusions). Scaled placental transfer was integrated into the pregnancy physiologically based pharmacokinetic model. For darunavir 600/100 mg twice a day, the predicted fetal maximum plasma concentration, trough concentration, time to maximum plasma concentration, and half-life were 1.1, 0.57 mg/L, 3, and 21 h, respectively. This indicates that the fetal population trough concentration is higher or around the half-maximal effective darunavir concentration for a resistant virus (0.55 mg/L). The results indicate that the population fetal exposure after oral maternal darunavir dosing is therapeutic and this may provide benefits to the prevention of mother-to-child transmission of human immunodeficiency virus. Moreover, this integrated approach provides a tool to prevent fetal toxicity or enhance the development of more selectively targeted fetal drug treatments.

Spatial modeling of personalized exposure dynamics: the case of pesticide use in small-scale agricultural production landscapes of the developing world.

PubMed

Leyk, Stefan; Binder, Claudia R; Nuckols, John R

2009-03-30

Pesticide poisoning is a global health issue with the largest impacts in the developing countries where residential and small-scale agricultural areas are often integrated and pesticides sprayed manually. To reduce health risks from pesticide exposure approaches for personalized exposure assessment (PEA) are needed. We present a conceptual framework to develop a spatial individual-based model (IBM) prototype for assessing potential exposure of farm-workers conducting small-scale agricultural production, which accounts for a considerable portion of global food crop production. Our approach accounts for dynamics in the contaminant distributions in the environment, as well as patterns of movement and activities performed on an individual level under different safety scenarios. We demonstrate a first prototype using data from a study area in a rural part of Colombia, South America. Different safety scenarios of PEA were run by including weighting schemes for activities performed under different safety conditions. We examined the sensitivity of individual exposure estimates to varying patterns of pesticide application and varying individual patterns of movement. This resulted in a considerable variation in estimates of magnitude, frequency and duration of exposure over the model runs for each individual as well as between individuals. These findings indicate the influence of patterns of pesticide application, individual spatial patterns of movement as well as safety conditions on personalized exposure in the agricultural production landscape that is the focus of our research. This approach represents a conceptual framework for developing individual based models to carry out PEA in small-scale agricultural settings in the developing world based on individual patterns of movement, safety conditions, and dynamic contaminant distributions. The results of our analysis indicate our prototype model is sufficiently sensitive to differentiate and quantify the influence of individual patterns of movement and decision-based pesticide management activities on potential exposure. This approach represents a framework for further understanding the contribution of agricultural pesticide use to exposure in the small-scale agricultural production landscape of many developing countries, and could be useful to evaluate public health intervention strategies to reduce risks to farm-workers and their families. Further research is needed to fully develop an operational version of the model.

Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy

NASA Astrophysics Data System (ADS)

Bian, Junguo; Sharp, Gregory C.; Park, Yang-Kyun; Ouyang, Jinsong; Bortfeld, Thomas; El Fakhri, Georges

2016-05-01

It is well-known that projections acquired over an angular range slightly over 180° (so-called short scan) are sufficient for fan-beam reconstruction. However, due to practical imaging conditions (projection data and reconstruction image discretization, physical factors, and data noise), the short-scan reconstructions may have different appearances and properties from the full-scan (scans over 360°) reconstructions. Nevertheless, short-scan configurations have been used in applications such as cone-beam CT (CBCT) for head-neck-cancer image-guided radiation therapy (IGRT) that only requires a small field of view due to the potential reduced imaging time and dose. In this work, we studied the image quality trade-off for full, short, and full/short scan configurations with both conventional filtered-backprojection (FBP) reconstruction and iterative reconstruction algorithms based on total-variation (TV) minimization for head-neck-cancer IGRT. Anthropomorphic and Catphan phantoms were scanned at different exposure levels with a clinical scanner used in IGRT. Both visualization- and numerical-metric-based evaluation studies were performed. The results indicate that the optimal exposure level and number of views are in the middle range for both FBP and TV-based iterative algorithms and the optimization is object-dependent and task-dependent. The optimal view numbers decrease with the total exposure levels for both FBP and TV-based algorithms. The results also indicate there are slight differences between FBP and TV-based iterative algorithms for the image quality trade-off: FBP seems to be more in favor of larger number of views while the TV-based algorithm is more robust to different data conditions (number of views and exposure levels) than the FBP algorithm. The studies can provide a general guideline for image-quality optimization for CBCT used in IGRT and other applications.

Investigation of cone-beam CT image quality trade-off for image-guided radiation therapy.

PubMed

Bian, Junguo; Sharp, Gregory C; Park, Yang-Kyun; Ouyang, Jinsong; Bortfeld, Thomas; El Fakhri, Georges

2016-05-07

It is well-known that projections acquired over an angular range slightly over 180° (so-called short scan) are sufficient for fan-beam reconstruction. However, due to practical imaging conditions (projection data and reconstruction image discretization, physical factors, and data noise), the short-scan reconstructions may have different appearances and properties from the full-scan (scans over 360°) reconstructions. Nevertheless, short-scan configurations have been used in applications such as cone-beam CT (CBCT) for head-neck-cancer image-guided radiation therapy (IGRT) that only requires a small field of view due to the potential reduced imaging time and dose. In this work, we studied the image quality trade-off for full, short, and full/short scan configurations with both conventional filtered-backprojection (FBP) reconstruction and iterative reconstruction algorithms based on total-variation (TV) minimization for head-neck-cancer IGRT. Anthropomorphic and Catphan phantoms were scanned at different exposure levels with a clinical scanner used in IGRT. Both visualization- and numerical-metric-based evaluation studies were performed. The results indicate that the optimal exposure level and number of views are in the middle range for both FBP and TV-based iterative algorithms and the optimization is object-dependent and task-dependent. The optimal view numbers decrease with the total exposure levels for both FBP and TV-based algorithms. The results also indicate there are slight differences between FBP and TV-based iterative algorithms for the image quality trade-off: FBP seems to be more in favor of larger number of views while the TV-based algorithm is more robust to different data conditions (number of views and exposure levels) than the FBP algorithm. The studies can provide a general guideline for image-quality optimization for CBCT used in IGRT and other applications.

A Satellite-Based Multi-Pollutant Index of Global Air Quality

NASA Technical Reports Server (NTRS)

Cooper, Mathew J.; Martin, Randall V.; vanDonkelaar, Aaron; Lamsal, Lok; Brauer, Michael; Brook, Jeffrey R.

2012-01-01

Air pollution is a major health hazard that is responsible formillions of annual excess deaths worldwide. Simpleindicators are useful for comparative studies and to asses strends over time. The development of global indicators hasbeen impeded by the lack of ground-based observations in vast regions of the world. Recognition is growing of the need for amultipollutant approach to air quality to better represent human exposure. Here we introduce the prospect of amultipollutant air quality indicator based on observations from satellite remote sensing.

Using Family-Based Exposure With Response Prevention to Treat Obsessive-Compulsive Disorder in Young Children: A Case Study.

PubMed

Herren, Jenny; Freeman, Jennifer; Garcia, Abbe

2016-11-01

Cognitive-behavioral therapy (CBT) using exposure with response prevention (ERP) is the treatment of choice for obsessive-compulsive disorder (OCD); however, developmental modifications should be considered when treating young children. This article presents a case study illustrating family-based CBT using ERP with a 7-year-old boy. The delivery of ERP for this case was guided by 3 main principles: (a) family involvement with a focus on reducing family accommodation, (b) understanding the functional relation between the client's obsessions and compulsions, and (c) creating conditions to facilitate habituation during exposure. Outcomes for this case indicate significant improvement in functioning and OCD symptoms. Results highlight the importance of family involvement and the applicability of using a function-based habituation framework when delivering ERP to this unique population. © 2016 Wiley Periodicals, Inc.

Metabolic Phenotyping Reveals a Lipid Mediator Response to Ionizing Radiation

PubMed Central

2015-01-01

Exposure to ionizing radiation has dramatically increased in modern society, raising serious health concerns. The molecular response to ionizing radiation, however, is still not completely understood. Here, we screened mouse serum for metabolic alterations following an acute exposure to γ radiation using a multiplatform mass-spectrometry-based strategy. A global, molecular profiling revealed that mouse serum undergoes a series of significant molecular alterations following radiation exposure. We identified and quantified bioactive metabolites belonging to key biochemical pathways and low-abundance, oxygenated, polyunsaturated fatty acids (PUFAs) in the two groups of animals. Exposure to γ radiation induced a significant increase in the serum levels of ether phosphatidylcholines (PCs) while decreasing the levels of diacyl PCs carrying PUFAs. In exposed mice, levels of pro-inflammatory, oxygenated metabolites of arachidonic acid increased, whereas levels of anti-inflammatory metabolites of omega-3 PUFAs decreased. Our results indicate a specific serum lipidomic biosignature that could be utilized as an indicator of radiation exposure and as novel target for therapeutic intervention. Monitoring such a molecular response to radiation exposure might have implications not only for radiation pathology but also for countermeasures and personalized medicine. PMID:25126707

Epidemiologic studies of glyphosate and cancer: a review.

PubMed

Mink, Pamela J; Mandel, Jack S; Sceurman, Bonnielin K; Lundin, Jessica I

2012-08-01

The United States Environmental Protection Agency and other regulatory agencies around the world have registered glyphosate as a broad-spectrum herbicide for use on multiple food and non-food use crops. Glyphosate is widely considered by regulatory authorities and scientific bodies to have no carcinogenic potential, based primarily on results of carcinogenicity studies of rats and mice. To examine potential cancer risks in humans, we reviewed the epidemiologic literature to evaluate whether exposure to glyphosate is associated causally with cancer risk in humans. We also reviewed relevant methodological and biomonitoring studies of glyphosate. Seven cohort studies and fourteen case-control studies examined the association between glyphosate and one or more cancer outcomes. Our review found no consistent pattern of positive associations indicating a causal relationship between total cancer (in adults or children) or any site-specific cancer and exposure to glyphosate. Data from biomonitoring studies underscore the importance of exposure assessment in epidemiologic studies, and indicate that studies should incorporate not only duration and frequency of pesticide use, but also type of pesticide formulation. Because generic exposure assessments likely lead to exposure misclassification, it is recommended that exposure algorithms be validated with biomonitoring data. Copyright © 2012 Elsevier Inc. All rights reserved.

Occupation and thyroid cancer.

PubMed

Aschebrook-Kilfoy, Briseis; Ward, Mary H; Della Valle, Curt T; Friesen, Melissa C

2014-05-01

Numerous occupational and environmental exposures have been shown to disrupt thyroid hormones, but much less is known about their relationships with thyroid cancer. Here we review the epidemiology studies of occupations and occupational exposures and thyroid cancer incidence to provide insight into preventable risk factors for thyroid cancer. The published literature was searched using the Web of Knowledge database for all articles through August 2013 that had in their text 'occupation' 'job' 'employment' or 'work' and 'thyroid cancer'. After excluding 10 mortality studies and 4 studies with less than 5 exposed incident cases, we summarised the findings of 30 articles that examined thyroid cancer incidence in relation to occupations or occupational exposure. The studies were grouped by exposure/occupation category, study design and exposure assessment approach. Where available, gender-stratified results are reported. The most studied (19 of 30 studies) and the most consistent associations were observed for radiation-exposed workers and healthcare occupations. Suggestive, but inconsistent, associations were observed in studies of pesticide-exposed workers and agricultural occupations. Findings for other exposures and occupation groups were largely null. The majority of studies had few exposed cases and assessed exposure based on occupation or industry category, self-report, or generic (population-based) job exposure matrices. The suggestive, but inconsistent findings for many of the occupational exposures reviewed here indicate that more studies with larger numbers of cases and better exposure assessment are necessary, particularly for exposures known to disrupt thyroid homeostasis.

Application of a unique test design to determine the chronic toxicity of boron to the aquatic worm Lumbriculus variegatus and fatmucket mussel Lampsilis siliquoidea.

PubMed

Hall, Scott; Lockwood, Rick; Harrass, Michael C

2014-01-01

The chronic (21- and 28-day) toxicity of boron was determined for two freshwater benthic macroinvertebrates: the fatmucket mussel Lampsilis siliquoidea and the aquatic worm Lumbriculus variegatus. The rapid depletion of boric acid from spiked sediments in tests using flow-through overlying waters was addressed by constant addition of boric acid to overlying water at concentrations matching those of the targeted porewater exposures. This proved highly successful in maintaining constant whole-sediment and sediment porewater boron concentrations. Boron sublethal 25 % inhibition concentration values based on porewater concentrations were 25.9 mg B/L (L. variegatus) and 38.5 mg B/L (L. siliquoidea), indicating similar test organism sensitivity. Expressed as dry whole-sediment values, the respective L. variegatus and L. siliquoidea sublethal (growth) IC25 values for whole-sediment exposures were 235.5 mg B/kg sediment dry weight (dw) and 310.6 mg B/kg dw. The worm lethality-based end points indicated greater sensitivity than the sublethal end points, bringing into question the validity of a "lethality" end point for L. variegatus given its fragmentation mode of reproduction. For comparison, water-only mussel exposures were tested resulting in an IC25 value of 34.6 mg B/L, which was within 20 % of the porewater value. This suggests that the primary route of boron exposure was through the aqueous phase. The results of this study indicated that for test materials that are readily water soluble, standard sediment test designs may be unsuitable, but water-only exposures can provide toxicological data representative of sediment tests.

Annama H chondrite—Mineralogy, physical properties, cosmic ray exposure, and parent body history

NASA Astrophysics Data System (ADS)

Kohout, TomáÅ.¡; Haloda, Jakub; Halodová, Patricie; Meier, Matthias M. M.; Maden, Colin; Busemann, Henner; Laubenstein, Matthias; Caffee, Marc. W.; Welten, Kees C.; Hopp, Jens; Trieloff, Mario; Mahajan, Ramakant R.; Naik, Sekhar; Trigo-Rodriguez, Josep M.; Moyano-Cambero, Carles E.; Oshtrakh, Michael I.; Maksimova, Alevtina A.; Chukin, Andrey V.; Semionkin, Vladimir A.; Karabanalov, Maksim S.; Felner, Israel; Petrova, Evgeniya V.; Brusnitsyna, Evgeniia V.; Grokhovsky, Victor I.; Yakovlev, Grigoriy A.; Gritsevich, Maria; Lyytinen, Esko; Moilanen, Jarmo; Kruglikov, Nikolai A.; Ishchenko, Aleksey V.

2017-08-01

The fall of the Annama meteorite occurred early morning (local time) on April 19, 2014 on the Kola Peninsula (Russia). Based on mineralogy and physical properties, Annama is a typical H chondrite. It has a high Ar-Ar age of 4.4 Ga. Its cosmic ray exposure history is atypical as it is not part of the large group of H chondrites with a prominent 7-8 Ma peak in the exposure age histograms. Instead, its exposure age is within uncertainty of a smaller peak at 30 ± 4 Ma. The results from short-lived radionuclides are compatible with an atmospheric pre-entry radius of 30-40 cm. However, based on noble gas and cosmogenic radionuclide data, Annama must have been part of a larger body (radius >65 cm) for a large part of its cosmic ray exposure history. The 10Be concentration indicates a recent (3-5 Ma) breakup which may be responsible for the Annama parent body size reduction to 30-35 cm pre-entry radius.

Exposure to the fungicide propamocarb causes gut microbiota dysbiosis and metabolic disorder in mice.

PubMed

Wu, Sisheng; Jin, Cuiyuan; Wang, Yueyi; Fu, Zhengwei; Jin, Yuanxiang

2018-06-01

Propamocarb (PM) is a widely used fungicide with property of affecting fatty acid and phospholipid biosynthesis in funguses. In this study, we explored its effects on mice gut microbiota and metabolism by exposing mice to 3, 30, and 300 mg/L PM through drinking water for a duration of 28 days. We observed that the transcription of hepatic genes related to regulate lipid metabolism were perturbed by PM exposure. The microbiota in the cecal contents and feces changed during or after PM exposure at phylum or genus levels. 16S rRNA gene sequencing for the cecal content revealed shifted in overall microbial structure after PM exposure, and operational taxonomic unit (OTU) analysis indicated that 32.2% of OTUs changed by 300 mg/mL PM exposure for 28 days. In addition, based on 1 H NMR analysis,a total of 20 fecal metabolites mainly including succinate, short chain fatty acids, bile acids and trimethylamine were found to be significantly influenced by exposure to 300 mg/L PM.,. These metabolites were tightly correlated to host metabolism. Our findings indicated that high doses of PM exposure could disturb mice metabolism through, or partly through, altering the gut microbiota and microbial metabolites. Copyright © 2017 Elsevier Ltd. All rights reserved.

Exploring childhood lead exposure through GIS: a review of the recent literature.

PubMed

Akkus, Cem; Ozdenerol, Esra

2014-06-18

Childhood exposure to lead remains a critical health control problem in the US. Integration of Geographic Information Systems (GIS) into childhood lead exposure studies significantly enhanced identifying lead hazards in the environment and determining at risk children. Research indicates that the toxic threshold for lead exposure was updated three times in the last four decades: 60 to 30 micrograms per deciliter (µg/dL) in 1975, 25 µg/dL in 1985, and 10 µb/dL in 1991. These changes revealed the extent of lead poisoning. By 2012 it was evident that no safe blood lead threshold for the adverse effects of lead on children had been identified and the Center for Disease Control (CDC) currently uses a reference value of 5 µg/dL. Review of the recent literature on GIS-based studies suggests that numerous environmental risk factors might be critical for lead exposure. New GIS-based studies are used in surveillance data management, risk analysis, lead exposure visualization, and community intervention strategies where geographically-targeted, specific intervention measures are taken.

Exploring Childhood Lead Exposure through GIS: A Review of the Recent Literature

PubMed Central

Akkus, Cem; Ozdenerol, Esra

2014-01-01

Childhood exposure to lead remains a critical health control problem in the US. Integration of Geographic Information Systems (GIS) into childhood lead exposure studies significantly enhanced identifying lead hazards in the environment and determining at risk children. Research indicates that the toxic threshold for lead exposure was updated three times in the last four decades: 60 to 30 micrograms per deciliter (µg/dL) in 1975, 25 µg/dL in 1985, and 10 µb/dL in 1991. These changes revealed the extent of lead poisoning. By 2012 it was evident that no safe blood lead threshold for the adverse effects of lead on children had been identified and the Center for Disease Control (CDC) currently uses a reference value of 5 µg/dL. Review of the recent literature on GIS-based studies suggests that numerous environmental risk factors might be critical for lead exposure. New GIS-based studies are used in surveillance data management, risk analysis, lead exposure visualization, and community intervention strategies where geographically-targeted, specific intervention measures are taken. PMID:24945189

Natural Hazard Management from a Coevolutionary Perspective: Exposure and Policy Response in the European Alps.

PubMed

Fuchs, Sven; Röthlisberger, Veronika; Thaler, Thomas; Zischg, Andreas; Keiler, Margreth

2017-03-04

A coevolutionary perspective is adopted to understand the dynamics of exposure to mountain hazards in the European Alps. A spatially explicit, object-based temporal assessment of elements at risk to mountain hazards (river floods, torrential floods, and debris flows) in Austria and Switzerland is presented for the period from 1919 to 2012. The assessment is based on two different data sets: (1) hazard information adhering to legally binding land use planning restrictions and (2) information on building types combined from different national-level spatial data. We discuss these transdisciplinary dynamics and focus on economic, social, and institutional interdependencies and interactions between human and physical systems. Exposure changes in response to multiple drivers, including population growth and land use conflicts. The results show that whereas some regional assets are associated with a strong increase in exposure to hazards, others are characterized by a below-average level of exposure. The spatiotemporal results indicate relatively stable hot spots in the European Alps. These results coincide with the topography of the countries and with the respective range of economic activities and political settings. Furthermore, the differences between management approaches as a result of multiple institutional settings are discussed. A coevolutionary framework widens the explanatory power of multiple drivers to changes in exposure and risk and supports a shift from structural, security-based policies toward an integrated, risk-based natural hazard management system.

Natural Hazard Management from a Coevolutionary Perspective: Exposure and Policy Response in the European Alps

PubMed Central

Fuchs, Sven; Röthlisberger, Veronika; Thaler, Thomas; Zischg, Andreas; Keiler, Margreth

2017-01-01

A coevolutionary perspective is adopted to understand the dynamics of exposure to mountain hazards in the European Alps. A spatially explicit, object-based temporal assessment of elements at risk to mountain hazards (river floods, torrential floods, and debris flows) in Austria and Switzerland is presented for the period from 1919 to 2012. The assessment is based on two different data sets: (1) hazard information adhering to legally binding land use planning restrictions and (2) information on building types combined from different national-level spatial data. We discuss these transdisciplinary dynamics and focus on economic, social, and institutional interdependencies and interactions between human and physical systems. Exposure changes in response to multiple drivers, including population growth and land use conflicts. The results show that whereas some regional assets are associated with a strong increase in exposure to hazards, others are characterized by a below-average level of exposure. The spatiotemporal results indicate relatively stable hot spots in the European Alps. These results coincide with the topography of the countries and with the respective range of economic activities and political settings. Furthermore, the differences between management approaches as a result of multiple institutional settings are discussed. A coevolutionary framework widens the explanatory power of multiple drivers to changes in exposure and risk and supports a shift from structural, security-based policies toward an integrated, risk-based natural hazard management system. PMID:28267154

Flood hazard management from a coevolutionary perspective: exposure and policy response in the European Alps

NASA Astrophysics Data System (ADS)

Fuchs, Sven; Röthlisberger, Veronika; Thaler, Thomas; Zischg, Andreas; Keiler, Margreth

2017-04-01

A coevolutionary perspective is adopted to understand the dynamics of exposure to hydrological hazards in the European Alps. A spatially explicit, object-based temporal assessment of elements at risk to flood hazards (river floods, torrential floods and debris flows) in Austria and Switzerland is presented for the 1919-2012 period. The assessment is based on two different datasets, (a) hazard information adhering to legally binding land use planning restrictions and (b) information on building types combined from different national level spatial data. We discuss these transdisciplinary dynamics and focus on economic, social and institutional interdependencies and interactions between human and physical systems. Exposure changes in the response to multiple drivers, including population growth and land use conflicts. The results show that while some regional assets are associated with a strong increase in exposure to hazards, others are characterized by a below-average level of exposure. The spatiotemporal results indicate relatively stable hot spots in the European Alps. These results coincide with the topography of the countries and with the respective range of economic activities and political settings. Furthermore, the differences between management approaches as a result of multiple institutional settings are discussed. A coevolutionary framework widens the explanatory power of multiple drivers to changes in exposure and risk, and supports a shift from structural, security-based policies towards an integrated, risk-based natural hazard management system.

Validity of at home model predictions as a proxy for personal exposure to radiofrequency electromagnetic fields from mobile phone base stations.

PubMed

Martens, Astrid L; Bolte, John F B; Beekhuizen, Johan; Kromhout, Hans; Smid, Tjabe; Vermeulen, Roel C H

2015-10-01

Epidemiological studies on the potential health effects of RF-EMF from mobile phone base stations require efficient and accurate exposure assessment methods. Previous studies have demonstrated that the 3D geospatial model NISMap is able to rank locations by indoor and outdoor RF-EMF exposure levels. This study extends on previous work by evaluating the suitability of using NISMap to estimate indoor RF-EMF exposure levels at home as a proxy for personal exposure to RF-EMF from mobile phone base stations. For 93 individuals in the Netherlands we measured personal exposure to RF-EMF from mobile phone base stations during a 24h period using an EME-SPY 121 exposimeter. Each individual kept a diary from which we extracted the time spent at home and in the bedroom. We used NISMap to model exposure at the home address of the participant (at bedroom height). We then compared model predictions with measurements for the 24h period, when at home, and in the bedroom by the Spearman correlation coefficient (rsp) and by calculating specificity and sensitivity using the 90th percentile of the exposure distribution as a cutpoint for high exposure. We found a low to moderate rsp of 0.36 for the 24h period, 0.51 for measurements at home, and 0.41 for measurements in the bedroom. The specificity was high (0.9) but with a low sensitivity (0.3). These results indicate that a meaningful ranking of personal RF-EMF can be achieved, even though the correlation between model predictions and 24h personal RF-EMF measurements is lower than with at home measurements. However, the use of at home RF-EMF field predictions from mobile phone base stations in epidemiological studies leads to significant exposure misclassification that will result in a loss of statistical power to detect health effects. Copyright © 2015 Elsevier Inc. All rights reserved.

The 737 graphite composite flight spoiler flight service evaluation

NASA Technical Reports Server (NTRS)

Stoecklin, R. L.

1975-01-01

The flight service experience of 108 graphite-epoxy spoilers on 737 transport aircraft, and related ground-based environmental exposure of graphite-epoxy material specimens were evaluated. Four spoilers were installed on each of 27 aircraft for a 5-year study. As of February 28, 1975, a total of 294,280 spoiler flight-hours and 460,686 spoiler landings were accumulated. Based on visual, ultrasonic, and destructive testing, no moisture migration into the honeycomb core and no core corrosion has occurred. Tests of removed spoilers and of ground-based exposure specimens after the first year of service indicate no significant changes in composite strength.

Surface microstructural features of scales in relation to toxic stress of Basic Violet-1.

PubMed

Kaur, Kirandeep; Kaur, Ramandeep; Kaur, Arvinder

2016-01-01

The present work deals with scanning electron microscopic (SEM) studies of the scales of Labeo rohita on exposure to lethal and sublethal doses of Basic Violet-1 (an important textile and hair colorant). The dye induced loosening of the scales and caused breakage and disorganization of lepidonts. Erosion of lepidonts occurred mostly in the fish exposed to 0.20 and 0.40 mg/L dye, during acute exposure and to 0.0225 and 0.045 mg/L dye, during the subchronic exposure. However, lepidonts were sloughed off from their sockets in 0.60 and 0.80 mg/L dye during acute exposure and in 0.09 mg/L dye during the subchronic exposure. Circuli, the base that provides anchorage to the lepidonts, got damaged, and tubercles responsible for coloration of a fish became atrophied with an increase in the duration of exposure. The results of the present investigation clearly indicated that exposure to Basic Violet-1 (BV-1) even at a concentration as low as 0.0225 mg was responsible for deleterious changes in the scale morphology of the test fish after 150 days of exposure. Similar changes were observed in the scales of the dead fish also. It can thus be suggested that this noninvasive technique is very helpful for evaluating the health status of an aquatic body. At the same time, the changes in ultramorphology of scales can act as an early indicator of the stress of very minute doses of dyes and even the scales of a dead fish can act as indicators of the untoward changes that would have occurred in the environment of the fish before death.

A novel air pollution index based on the relative risk of daily mortality associated with short-term exposure to common air pollutants

NASA Astrophysics Data System (ADS)

Cairncross, Eugene K.; John, Juanette; Zunckel, Mark

Communication of the complex relationship between air pollutant exposure and ill health is essential to an air pollution information system. We propose a novel air pollution index (API) system based on the relative risk of the well-established increased daily mortality associated with short-term exposure to common air pollutants: particulate matter (PM 10, PM 2.5), sulphur dioxide, ozone, nitrogen dioxide and carbon monoxide. To construct our index system, the total incremental daily mortality risk of exposure to these pollutants was associated with an index value ranging from 0 to 10. The index scale is linear with respect to incremental risk. The index is open ended, although, for convenience, an index of 10 is assigned for exposures yielding indices ⩾10. To illustrate the application of this API system, a set of published relative risk factors are used to calculate sub-index values for each pollutant, in the range of air pollutant concentrations commonly experienced in urban areas. To account for the reality of ubiquitous simultaneous exposure to a mixture of the common air pollutants, the final API is the sum of the normalised values of the individual indices for PM 10, PM 2.5, sulphur dioxide, ozone, nitrogen dioxide and carbon monoxide. This establishes a self-consistent index system where a given index value corresponds to the same daily mortality risk associated with the combined exposure to the common air pollutants. To facilitate health-risk communication, index values are colour coded and associated with broad health-risk descriptors. The utility of the proposed API is illustrated by applying it to monitored ambient concentration data for the City of Cape Town, South Africa.

Strength through adversity: Moderate lifetime stress exposure is associated with psychological resilience in breast cancer survivors.

PubMed

Dooley, Larissa N; Slavich, George M; Moreno, Patricia I; Bower, Julienne E

2017-12-01

Stress research typically emphasizes the toxic effects of stress, but recent evidence has suggested that stress exposure, in moderation, can facilitate resilience. To test whether moderate stress exposure promotes psychological resilience to cancer, we examined the relationship between lifetime stress exposure prior to cancer diagnosis and postdiagnosis psychological functioning among 122 breast cancer survivors. Lifetime acute and chronic stress was assessed using an interview-based measure, and psychological functioning was assessed using measures of cancer-related intrusive thoughts and positive and negative affect. Results indicated that acute stress exposure was associated with cancer-related intrusive thoughts in a quadratic fashion (p = .016), such that participants with moderate acute stress reported fewer intrusive thoughts compared to those with low or high acute stress. Similarly, a quadratic relationship emerged between acute stress exposure and positive affect (p = .009), such that individuals with moderate acute stress reported the highest levels of positive affect. In contrast, acute and chronic stress were related to negative affect in a positive, linear fashion (ps < .05). In conclusion, moderate stress exposure was associated with indicators of psychological resilience among breast cancer survivors, supporting stress exposure as a key factor influencing adjustment to breast cancer and providing evidence for stress-induced resilience in a novel population. Copyright © 2017 John Wiley & Sons, Ltd.

The evaluation of stack metal emissions from hazardous waste incinerators: assessing human exposure through noninhalation pathways.

PubMed Central

Sedman, R M; Polisini, J M; Esparza, J R

1994-01-01

Potential public health effects associated with exposure to metal emissions from hazardous waste incinerators through noninhalation pathways were evaluated. Instead of relying on modeling the movement of toxicants through various environmental media, an approach based on estimating changes from baseline levels of exposure was employed. Changes in soil and water As, Cd, Hg, Pb, Cr, and Be concentrations that result from incinerator emissions were first determined. Estimates of changes in human exposure due to direct contact with shallow soil or the ingestion of surface water were then ascertained. Projected changes in dietary intakes of metals due to incinerator emissions were estimated based on changes from baseline dietary intakes that are monitored in U.S. Food and Drug Administration total diet studies. Changes from baseline intake were deemed to be proportional to the projected changes in soil or surface water metal concentrations. Human exposure to metals emitted from nine hazardous waste incinerators were then evaluated. Metal emissions from certain facilities resulted in tangible human exposure through noninhalation pathways. However, the analysis indicated that the deposition of metals from ambient air would result in substantially greater human exposure through noninhalation pathways than the emissions from most of the facilities. PMID:7925180

Investigation on thermal oxidative aging of nitrile rubber (NBR) O-rings under compression stress

NASA Astrophysics Data System (ADS)

Liu, X. R.; Zhang, W. F.; Lou, W. T.; Huang, Y. X.; Dai, W.

2017-11-01

The degradation behaviors of nitrile rubber O-rings exposure to air under compression were investigated at three elevated temperatures. The physical and mechanical properties of the aging samples before and after exposure at selected time were studied by measuring weight loss, tensile strength and elongation at break. The Attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy and fracture morphology were used to reveal the microstructural changes of the aging samples. The results indicate that the weight decreased with exposure time and temperature. Based on the results of the crosslinking density, the crosslinking predominates during the most of aging process. The significant changes in tensile strength and elongation at break also indicate the severe degradation in air. The fracture morphology results show that the fracture surface after 64 days of exposure to air turns rough and present defects. The ATR-FTIR results demonstrate that the hydroxyl groups were formed for the samples aged in air.

Developing Vulnerability Analysis Method for Climate Change Adaptation on Agropolitan Region in Malang District

NASA Astrophysics Data System (ADS)

Sugiarto, Y.; Perdinan; Atmaja, T.; Wibowo, A.

2017-03-01

Agriculture plays a strategic role in strengthening sustainable development. Based on agropolitan concept, the village becomes the center of economic activities by combining agriculture, agro-industry, agribusiness and tourism that able to create high value-added economy. The impact of climate change on agriculture and water resources may increase the pressure on agropolitan development. The assessment method is required to measure the vulnerability of area-based communities in the agropolitan to climate change impact. An analysis of agropolitan vulnerability was conducted in Malang district based on four aspects and considering the availability and distribution of water as the problem. The indicators used to measure was vulnerability component which consisted of sensitivity and adaptive capacity and exposure component. The studies earned 21 indicators derived from the 115 village-based data. The results of vulnerability assessments showed that most of the villages were categorised at a moderate level. Around 20% of 388 villages were categorized at high to very high level of vulnerability due to low level of agricultural economic. In agropolitan region within the sub-district of Poncokusumo, the vulnerability of the villages varies between very low to very high. The most villages were vulnerable due to lower adaptive capacity, eventhough the level of sensitivity and exposure of all villages were relatively similar. The existence of water resources was the biggest contributor to the high exposure of the villages in Malang district, while the reception of credit facilities and source of family income were among the indicators that lead to high sensitivity component.

Long- and Short-Term Health Effects of Pesticide Exposure: A Cohort Study from China

PubMed Central

Li, Yifan; Zhang, Chao; Yin, Yanhong; Chen, Zhaohui; Jin, Yanhong; Cai, Jinyang; Cui, Fang

2015-01-01

Pesticides are extensively used by farmers in China. However, the effects of pesticides on farmers’ health have not yet been systematically studied. This study evaluated the effects of pesticides exposure on hematological and neurological indicators over 3 years and 10 days respectively. A cohort of 246 farmers was randomly selected from 3 provinces (Guangdong, Jiangxi, and Hebei) in China. Two rounds of health investigations, including blood tests and neurological examinations, were conducted by medical doctors before and after the crop season in 2012. The data on pesticide use in 2009–2011 were collected retrospectively via face-to-face interviews and the 2012 data were collected from personal records maintained by participants prospectively. Ordinary least square (OLS), Probit, and fixed effect models were used to evaluate the relationship between pesticides exposure frequency and the health indicators. Long-term pesticide exposure was found to be associated with increased abnormality of nerve conductions, especially in sensory nerves. It also affected a wide spectrum of health indicators based on blood tests and decreased the tibial nerve compound muscle action potential amplitudes. Short-term health effects included alterations in complete blood count, hepatic and renal functions, and nerve conduction velocities and amplitudes. However, these effects could not be detected after 3 days following pesticide exposure. Overall, our results demonstrate that pesticide exposure adversely affects blood cells, the liver, and the peripheral nervous system. Future studies are needed to elucidate the specific effects of each pesticide and the mechanisms of these effects. PMID:26042669

Measuring Exposure to Direct-to-Consumer Advertising—A Validation Study in the Context of Cancer-Related Treatment Advertising

PubMed Central

Tan, Andy SL; Hornik, Robert C

2014-01-01

This research examines two recurrent conceptual issues of measuring media exposure in survey research in the context of cancer-related direct-to-consumer advertising (CR-DTCA)—the level of content specificity of survey items and the benefits of providing exemplars to aid recall. We evaluated three candidate measures of cancer patients’ self-reported exposure to CR-DTCA; these measures varied in content specificity and provision of ad exemplars. Using data from two distinct population-based surveys, we assessed the performance of each measure based on several reliability and validity criteria. Results across both surveys indicate that all three measures performed equally well in terms of internal consistency, convergent, nomological, and discriminant validity with a few minor differences between these measures. Increased content specificity or inclusion of ad exemplars did not result in better performance of the exposure measures. Participants were able to extrapolate from ad exemplars to report their exposure to broad categories of CR-DTCA. The briefest of the three measures posed the lowest level of survey costs among the three measures and was deployed successfully for both mailed and internet-based survey administration. We discussed future directions for application of these findings in DTCA research for other illness and for media exposure research more generally. PMID:24693332

Amplicon-Based Sequencing of Soil Fungi from Wood Preservative Test Sites

PubMed Central

Kirker, Grant T.; Bishell, Amy B.; Jusino, Michelle A.; Palmer, Jonathan M.; Hickey, William J.; Lindner, Daniel L.

2017-01-01

Soil samples were collected from field sites in two AWPA (American Wood Protection Association) wood decay hazard zones in North America. Two field plots at each site were exposed to differing preservative chemistries via in-ground installations of treated wood stakes for approximately 50 years. The purpose of this study is to characterize soil fungal species and to determine if long term exposure to various wood preservatives impacts soil fungal community composition. Soil fungal communities were compared using amplicon-based DNA sequencing of the internal transcribed spacer 1 (ITS1) region of the rDNA array. Data show that soil fungal community composition differs significantly between the two sites and that long-term exposure to different preservative chemistries is correlated with different species composition of soil fungi. However, chemical analyses using ICP-OES found levels of select residual preservative actives (copper, chromium and arsenic) to be similar to naturally occurring levels in unexposed areas. A list of indicator species was compiled for each treatment-site combination; functional guild analyses indicate that long-term exposure to wood preservatives may have both detrimental and stimulatory effects on soil fungal species composition. Fungi with demonstrated capacity to degrade industrial pollutants were found to be highly correlated with areas that experienced long-term exposure to preservative testing. PMID:29093702

Unequal exposure to ecological hazards: environmental injustices in the Commonwealth of Massachusetts.

PubMed Central

Faber, Daniel R; Krieg, Eric J

2002-01-01

This study analyzes the social and geographic distribution of ecological hazards across 368 communities in the Commonwealth of Massachusetts. Combining census data with a variety of environmental data, we tested for and identified both income-based and racially based biases to the geographic distribution of 17 different types of environmentally hazardous sites and industrial facilities. We also developed a composite measure of cumulative exposure to compare the relative overall risks characteristic of each community. To the best of our knowledge, this point system makes this the first environmental justice study to develop a means for measuring and ranking cumulative exposure for communities. The study also controls for the intensity of hazards in each community by accounting for the area across which hazards are distributed. The findings indicate that ecologically hazardous sites and facilities are disproportionately located and concentrated in communities of color and working-class communities. The implication of this research for policymakers and citizen advocates is that cumulative exposure of residents to environmentally hazardous facilities and sites should receive greater consideration regarding community demographics and environmental health indicators. We conclude that the provision of additional resources for environmental monitoring and ranking, as well as yearly progress reports, is necessary for communities and state agencies to achieve equal access to clean and healthy environments for all residents. PMID:11929739

Including non-dietary sources into an exposure assessment of the European Food Safety Authority: The challenge of multi-sector chemicals such as Bisphenol A.

PubMed

von Goetz, N; Pirow, R; Hart, A; Bradley, E; Poças, F; Arcella, D; Lillegard, I T L; Simoneau, C; van Engelen, J; Husoy, T; Theobald, A; Leclercq, C

2017-04-01

In the most recent risk assessment for Bisphenol A for the first time a multi-route aggregate exposure assessment was conducted by the European Food Safety Authority. This assessment includes exposure via dietary sources, and also contributions of the most important non-dietary sources. Both average and high aggregate exposure were calculated by source-to-dose modeling (forward calculation) for different age groups and compared with estimates based on urinary biomonitoring data (backward calculation). The aggregate exposure estimates obtained by forward and backward modeling are in the same order of magnitude, with forward modeling yielding higher estimates associated with larger uncertainty. Yet, only forward modeling can indicate the relative contribution of different sources. Dietary exposure, especially via canned food, appears to be the most important exposure source and, based on the central aggregate exposure estimates, contributes around 90% to internal exposure to total (conjugated plus unconjugated) BPA. Dermal exposure via thermal paper and to a lesser extent via cosmetic products may contribute around 10% for some age groups. The uncertainty around these estimates is considerable, but since after dermal absorption a first-pass metabolism of BPA by conjugation is lacking, dermal sources may be of equal or even higher toxicological relevance than dietary sources. Copyright © 2017 Elsevier Inc. All rights reserved.

Exposure ages of carbonaceous chondrites, 1

NASA Technical Reports Server (NTRS)

Nishiizumi, K.; Arnold, J. R.; Caffee, M. W.; Finkel, R. C.; Southon, J. R.; Nagai, H.; Honda, M.; Sharma, P.; Imamura, M.; Kobayashi, K.

1993-01-01

The recent exposure histories of carbonaceous chondrites have been investigated using cosmogenic radionuclides. Our results may indicate a clustering of exposure ages of C1 and C2 chondrites into two peaks, 0.2 My and 0.6 My, perhaps implying two collisional events of Earth-crossing parent bodies. Among carbonaceous chondrites are some having short exposure ages which Mazor et al. hypothesized cluster into a small number of families. This hypothesis is based on spallogenic Ne-21 exposure ages, which in some instances are difficult to determine owing to the large amounts of trapped noble gases in carbonaceous chondrites. Also, since Ne-21 is stable, it integrates a sample's entire exposure history, so meteorites with complex exposure histories are difficult to understand using exclusively Ne-21. Cosmogenic radionuclides provide an alternative means of determining the recent cosmic ray exposure duration. To test the hypothesis of Mazor et al. we have begun a systematic investigation of exposure histories of Antarctic and non-Antarctic carbonaceous chondrites especially C2s.

Chronic Exposure to Tributyltin Induces Brain Functional Damage in Juvenile Common Carp (Cyprinus carpio)

PubMed Central

Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

2015-01-01

The aim of the present study was to investigate the effect of Tributyltin (TBT) on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase), Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide) in the brain of common carp were evaluated. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, a low level and short-term TBT-induced stress could not induce the notable responses of the fish brain, but long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on the measured parameters). The results also strongly indicated that neurotoxicity of TBT to fish. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity. PMID:25879203

Chronic exposure to Tributyltin induces brain functional damage in juvenile common carp (Cyprinus carpio).

PubMed

Li, Zhi-Hua; Li, Ping; Shi, Ze-Chao

2015-01-01

The aim of the present study was to investigate the effect of Tributyltin (TBT) on brain function and neurotoxicity of freshwater teleost. The effects of long-term exposure to TBT on antioxidant related indices (MDA, malondialdehyde; SOD, superoxide dismutase; CAT, catalase; GR, glutathione reductase; GPx, glutathione peroxidase), Na+-K+-ATPase and neurological parameters (AChE, acetylcholinesterase; MAO, monoamine oxidase; NO, nitric oxide) in the brain of common carp were evaluated. Fish were exposed to sublethal concentrations of TBT (75 ng/L, 0.75 μg/L and 7.5 μg/L) for 15, 30, and 60 days. Based on the results, a low level and short-term TBT-induced stress could not induce the notable responses of the fish brain, but long-term exposure (more than 15 days) to TBT could lead to obvious physiological-biochemical responses (based on the measured parameters). The results also strongly indicated that neurotoxicity of TBT to fish. Thus, the measured physiological responses in fish brain could provide useful information to better understand the mechanisms of TBT-induced bio-toxicity.

Are some people suffering as a result of increasing mass exposure of the public to ultrasound in air?

PubMed

Leighton, T G

2016-01-01

New measurements indicate that the public are being exposed, without their knowledge, to airborne ultrasound. Existing guidelines are insufficient for such exposures; the vast majority refers to occupational exposure only (where workers are aware of the exposure, can be monitored and can wear protection). Existing guidelines are based on an insufficient evidence base, most of which was collected over 40 years ago by researchers who themselves considered it insufficient to finalize guidelines, but which produced preliminary guidelines. This warning of inadequacy was lost as nations and organizations issued 'new' guidelines based on these early guidelines, and through such repetition generated a false impression of consensus. The evidence base is so slim that few reports have progressed far along the sequence from anecdote to case study, to formal scientific controlled trials and epidemiological studies. Early studies reported hearing threshold shifts, nausea, headache, fatigue, migraine and tinnitus, but there is insufficient research on human subjects, and insufficient measurement of fields, to assess what health risk current occupational and public exposures might produce. Furthermore, the assumptions underpinning audiology and physical measurements at high frequencies must be questioned: simple extrapolation of approaches used at lower frequencies does not address current unknowns. Recommendations are provided.

Are some people suffering as a result of increasing mass exposure of the public to ultrasound in air?

PubMed Central

Leighton, T. G.

2016-01-01

New measurements indicate that the public are being exposed, without their knowledge, to airborne ultrasound. Existing guidelines are insufficient for such exposures; the vast majority refers to occupational exposure only (where workers are aware of the exposure, can be monitored and can wear protection). Existing guidelines are based on an insufficient evidence base, most of which was collected over 40 years ago by researchers who themselves considered it insufficient to finalize guidelines, but which produced preliminary guidelines. This warning of inadequacy was lost as nations and organizations issued ‘new’ guidelines based on these early guidelines, and through such repetition generated a false impression of consensus. The evidence base is so slim that few reports have progressed far along the sequence from anecdote to case study, to formal scientific controlled trials and epidemiological studies. Early studies reported hearing threshold shifts, nausea, headache, fatigue, migraine and tinnitus, but there is insufficient research on human subjects, and insufficient measurement of fields, to assess what health risk current occupational and public exposures might produce. Furthermore, the assumptions underpinning audiology and physical measurements at high frequencies must be questioned: simple extrapolation of approaches used at lower frequencies does not address current unknowns. Recommendations are provided. PMID:26997897

Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential

PubMed Central

Mitchell, Jade; Arnot, Jon A.; Jolliet, Olivier; Georgopoulos, Panos G.; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A.; Vallero, Daniel A.

2014-01-01

While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA’s need to develop novel approaches and tools for rapidly prioritizing chemicals, a “Challenge” was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA’s effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. PMID:23707726

Comparison of modeling approaches to prioritize chemicals based on estimates of exposure and exposure potential.

PubMed

Mitchell, Jade; Arnot, Jon A; Jolliet, Olivier; Georgopoulos, Panos G; Isukapalli, Sastry; Dasgupta, Surajit; Pandian, Muhilan; Wambaugh, John; Egeghy, Peter; Cohen Hubal, Elaine A; Vallero, Daniel A

2013-08-01

While only limited data are available to characterize the potential toxicity of over 8 million commercially available chemical substances, there is even less information available on the exposure and use-scenarios that are required to link potential toxicity to human and ecological health outcomes. Recent improvements and advances such as high throughput data gathering, high performance computational capabilities, and predictive chemical inherency methodology make this an opportune time to develop an exposure-based prioritization approach that can systematically utilize and link the asymmetrical bodies of knowledge for hazard and exposure. In response to the US EPA's need to develop novel approaches and tools for rapidly prioritizing chemicals, a "Challenge" was issued to several exposure model developers to aid the understanding of current systems in a broader sense and to assist the US EPA's effort to develop an approach comparable to other international efforts. A common set of chemicals were prioritized under each current approach. The results are presented herein along with a comparative analysis of the rankings of the chemicals based on metrics of exposure potential or actual exposure estimates. The analysis illustrates the similarities and differences across the domains of information incorporated in each modeling approach. The overall findings indicate a need to reconcile exposures from diffuse, indirect sources (far-field) with exposures from directly, applied chemicals in consumer products or resulting from the presence of a chemical in a microenvironment like a home or vehicle. Additionally, the exposure scenario, including the mode of entry into the environment (i.e. through air, water or sediment) appears to be an important determinant of the level of agreement between modeling approaches. Copyright © 2013 Elsevier B.V. All rights reserved.

Occupational exposure to beryllium in French enterprises: a survey of airborne exposure and surface levels.

PubMed

Vincent, Raymond; Catani, Jacques; Créau, Yvon; Frocaut, Anne-Marie; Good, Andrée; Goutet, Pierre; Hou, Alain; Leray, Fabrice; André-Lesage, Marie-Ange; Soyez, Alain

2009-06-01

An assessment survey of occupational exposure to beryllium (Be) was conducted in France between late 2004 and the end of 2006. Exposure estimates were based on the analytical results of samples collected from workplace air and from work surfaces in 95 facilities belonging to 37 sectors of activity. The results of this study indicated airborne Be concentrations in excess of the occupational exposure limit value of 2 microg m(-3) recommended in France. Metallurgy and electronic component manufacturing represented the activities and occupations where workers had the highest arithmetic mean exposures to Be. Surface contamination levels were also high and frequently exceeded thresholds recommended by different bodies. These results should prompt the development of prevention programmes that include Be substitution, process control and surface decontamination, in conjunction with suitable medical surveillance.

High-Throughput Models for Exposure-Based Chemical ...

EPA Pesticide Factsheets

The United States Environmental Protection Agency (U.S. EPA) must characterize potential risks to human health and the environment associated with manufacture and use of thousands of chemicals. High-throughput screening (HTS) for biological activity allows the ToxCast research program to prioritize chemical inventories for potential hazard. Similar capabilities for estimating exposure potential would support rapid risk-based prioritization for chemicals with limited information; here, we propose a framework for high-throughput exposure assessment. To demonstrate application, an analysis was conducted that predicts human exposure potential for chemicals and estimates uncertainty in these predictions by comparison to biomonitoring data. We evaluated 1936 chemicals using far-field mass balance human exposure models (USEtox and RAIDAR) and an indicator for indoor and/or consumer use. These predictions were compared to exposures inferred by Bayesian analysis from urine concentrations for 82 chemicals reported in the National Health and Nutrition Examination Survey (NHANES). Joint regression on all factors provided a calibrated consensus prediction, the variance of which serves as an empirical determination of uncertainty for prioritization on absolute exposure potential. Information on use was found to be most predictive; generally, chemicals above the limit of detection in NHANES had consumer/indoor use. Coupled with hazard HTS, exposure HTS can place risk earlie

T cell-based tracking of multidrug resistant tuberculosis infection after brief exposure.

PubMed

Richeldi, Luca; Ewer, Katie; Losi, Monica; Bergamini, Barbara M; Roversi, Pietro; Deeks, Jonathan; Fabbri, Leonardo M; Lalvani, Ajit

2004-08-01

Molecular epidemiology indicates significant transmission of Mycobacterium tuberculosis after casual contact with infectious tuberculosis cases. We investigated M. tuberculosis transmission after brief exposure using a T cell-based assay, the enzyme-linked-immunospot (ELISPOT) for IFN-gamma. After childbirth, a mother was diagnosed with sputum smear-positive multidrug-resistant tuberculosis. Forty-one neonates and 47 adults were present during her admission on the maternity unit; 11 weeks later, all underwent tuberculin skin testing (TST) and ELISPOT. We correlated test results with markers of exposure to the index case. The participants, who were asymptomatic and predominantly had no prior tuberculosis exposure, had 6.05 hours mean exposure (range: 0-65 hours) to the index case. Seventeen individuals, including two newborns, were ELISPOT-positive, and ELISPOT results correlated significantly with three of four predefined measures of tuberculosis exposure. For each hour sharing room air with the index case, the odds of a positive ELISPOT result increased by 1.05 (95% CI: 1.02-1.09, p = 0.003). Only four adults were TST-positive and TST results did not correlate with exposure. Thus, ELISPOT, but not TST, suggested quite extensive nosocomial transmission of multidrug-resistant M. tuberculosis after brief exposure. These results help to explain the apparent importance of casual contact for tuberculosis transmission, and may have implications for prevention.

A simple method for assessing occupational exposure via the one-way random effects model.

PubMed

Krishnamoorthy, K; Mathew, Thomas; Peng, Jie

2016-11-01

A one-way random effects model is postulated for the log-transformed shift-long personal exposure measurements, where the random effect in the model represents an effect due to the worker. Simple closed-form confidence intervals are proposed for the relevant parameters of interest using the method of variance estimates recovery (MOVER). The performance of the confidence bounds is evaluated and compared with those based on the generalized confidence interval approach. Comparison studies indicate that the proposed MOVER confidence bounds are better than the generalized confidence bounds for the overall mean exposure and an upper percentile of the exposure distribution. The proposed methods are illustrated using a few examples involving industrial hygiene data.

A study of the effects of long-term exposure to fuels and fluids on the behavior of advanced composite materials

NASA Technical Reports Server (NTRS)

Tanimoto, E. Y.

1981-01-01

The periodic testing and evaluation of graphite/epoxy and Kevlar/epoxy material systems after subjecting test specimens to prolonged exposure to several laboratory-controlled environments deemed typical of normal aircraft operations is discussed. It is noted that specimen immersion in water or water-based fluids resulted in the greatest effect on the mechanical properties tested. Also, the environmental fluids showed a tendency to affect Kevlar/epoxy systems at an earlier exposure period than the graphite/epoxy systems. Results also indicate mechanical property strength retention generally being lower for the Kevlar/epoxy systems when compared to the corresponding graphite/epoxy systems in similar environments, after prolonged exposure.

Treating youths with selective mutism with an alternating design of exposure-based practice and contingency management.

PubMed

Vecchio, Jennifer; Kearney, Christopher A

2009-12-01

Selective mutism is a severe childhood disorder involving failure to speak in public situations in which speaking is expected. The present study examined 9 youths with selective mutism treated with child-focused, exposure-based practices and parent-focused contingency management via an alternating treatments design. Broadband measures of functioning were employed, but particular focus was made on behavioral assessment of words spoken audibly and daily in public situations. Treatment ranged from 8 to 32 sessions and resulted in positive end-state functioning for 8 of 9 participants. Broader analyses indicated greater effectiveness for exposure-based practice than contingency management. The results support recent case reports of behavioral treatment for this population but in more rigorous fashion. Clinical and research challenges are discussed, including caveats about length and intensity of treatment for this population and need to develop standardized daily measures.

Systematic Review of Screening and Surveillance Programs to Protect Workers from Nanomaterials

PubMed Central

Gulumian, Mary; Verbeek, Jos; Sanabria, Natasha; de Jager, Pieter

2016-01-01

Background Screening and surveillance approaches for workers exposed to nanomaterials could aid in early detection of health effects, provide data for epidemiological studies and inform action to decrease exposure. The aim of this review is to identify such screening and surveillance approaches, in order to extract available data regarding (i) the studies that have successfully been implemented in present day, (ii) identification of the most common and/or toxic nano-related health hazards for workers and (iii) possible exposure surveillance markers. This review contributes to the current understanding of the risk associated with nanomaterials by determining the knowledge gap and making recommendations based on current findings. Methods A systematic review was conducted. PubMed and Embase were searched to identify articles reporting on any surveillance-related study that described both exposure to nanomaterials and the health indicators that were measured. Four reviewers worked in pairs to independently assess the eligibility of studies and risk of bias before extraction of data. Studies were categorised according to the type of study and the medical surveillance performed, which included the type of nanomaterial, any exposure details provided, as well as health indicators and biomarkers tested. Results Initially 92 studies were identified, from which 84 full texts were assessed for eligibility. Seven studies met all the inclusion criteria, i.e. those performed in Taiwan, Korea, Czech Republic and the US. Of these, six compared health indicators between exposed and unexposed workers and one study described a surveillance program. All studies were at a high risk of bias. Workers were exposed to a mix of nanomaterials in three studies, carbon-based nanomaterials in two studies, nano-silver in one study and nano-titanium oxide in the other study. Two studies did not find a difference in biomarkers between exposed and unexposed workers. In addition, differences in early effects on pulmonary function or neurobehavioral tests were not observed. One study found an increased prevalence of allergic dermatitis and “sneezing” in the exposed group. Conclusions This review of recently published data on surveillance studies proves that there is a gap in the current knowledge, where most of the surveillance-related studies reported do not follow a set format that provides the required information on ENM characterisation, the type of exposure and the measured indicators/biomarkers. Hence, there is very low quality evidence that screening and surveillance might detect adverse health effects associated with workplace exposure. This systematic review is relevant because it proves that, although surveillance programs have been initiated and preliminary results are being published, the current studies are actually not answering the important questions or solving the overall problem regarding what the potential health hazards are among workers either handling or potentially exposed to ENMs. The recommendations, thus proposed, are based on an obvious need for (i) exposure registries, where longitudinal follow-up studies should inform surveillance, (ii) known exposure measurements or summary indices for ENMs as a reference (iii) validation of candidate biomarkers and (iv) studies that compare the effects of these surveillance approaches to usual care, e.g. those commonly followed for bulk-size hazardous materials. PMID:27829014

Measuring combined exposure to environmental pressures in urban areas: an air quality and noise pollution assessment approach.

PubMed

Vlachokostas, Ch; Achillas, Ch; Michailidou, A V; Moussiopoulos, Nu

2012-02-01

This study presents a methodological scheme developed to provide a combined air and noise pollution exposure assessment based on measurements from personal portable monitors. Provided that air and noise pollution are considered in a co-exposure approach, they represent a significant environmental hazard to public health. The methodology is demonstrated for the city of Thessaloniki, Greece. The results of an extensive field campaign are presented and the variations in personal exposure between modes of transport, routes, streets and transport microenvironments are evaluated. Air pollution and noise measurements were performed simultaneously along several commuting routes, during the morning and evening rush hours. Combined exposure to environmental pollutants is highlighted based on the Combined Exposure Factor (CEF) and Combined Dose and Exposure Factor (CDEF). The CDEF takes into account the potential relative uptake of each pollutant by considering the physical activities of each citizen. Rather than viewing environmental pollutants separately for planning and environmental sustainability considerations, the possibility of an easy-to-comprehend co-exposure approach based on these two indices is demonstrated. Furthermore, they provide for the first time a combined exposure assessment to these environmental pollutants for Thessaloniki and in this sense they could be of importance for local public authorities and decision makers. A considerable environmental burden for the citizens of Thessaloniki, especially for VOCs and noise pollution levels is observed. The material herein points out the importance of measuring public health stressors and the necessity of considering urban environmental pollution in a holistic way. Copyright © 2011 Elsevier Ltd. All rights reserved.

Flexible Meta-Regression to Assess the Shape of the Benzene–Leukemia Exposure–Response Curve

PubMed Central

Vlaanderen, Jelle; Portengen, Lützen; Rothman, Nathaniel; Lan, Qing; Kromhout, Hans; Vermeulen, Roel

2010-01-01

Background Previous evaluations of the shape of the benzene–leukemia exposure–response curve (ERC) were based on a single set or on small sets of human occupational studies. Integrating evidence from all available studies that are of sufficient quality combined with flexible meta-regression models is likely to provide better insight into the functional relation between benzene exposure and risk of leukemia. Objectives We used natural splines in a flexible meta-regression method to assess the shape of the benzene–leukemia ERC. Methods We fitted meta-regression models to 30 aggregated risk estimates extracted from nine human observational studies and performed sensitivity analyses to assess the impact of a priori assessed study characteristics on the predicted ERC. Results The natural spline showed a supralinear shape at cumulative exposures less than 100 ppm-years, although this model fitted the data only marginally better than a linear model (p = 0.06). Stratification based on study design and jackknifing indicated that the cohort studies had a considerable impact on the shape of the ERC at high exposure levels (> 100 ppm-years) but that predicted risks for the low exposure range (< 50 ppm-years) were robust. Conclusions Although limited by the small number of studies and the large heterogeneity between studies, the inclusion of all studies of sufficient quality combined with a flexible meta-regression method provides the most comprehensive evaluation of the benzene–leukemia ERC to date. The natural spline based on all data indicates a significantly increased risk of leukemia [relative risk (RR) = 1.14; 95% confidence interval (CI), 1.04–1.26] at an exposure level as low as 10 ppm-years. PMID:20064779

An epigenome-wide association meta-analysis of prenatal maternal stress in neonates: A model approach for replication

PubMed Central

Rijlaarsdam, Jolien; Pappa, Irene; Walton, Esther; Bakermans-Kranenburg, Marian J.; Mileva-Seitz, Viara R.; Rippe, Ralph C.A.; Roza, Sabine J.; Jaddoe, Vincent W.V.; Verhulst, Frank C.; Felix, Janine F.; Cecil, Charlotte A.M.; Relton, Caroline L.; Gaunt, Tom R.; McArdle, Wendy; Mill, Jonathan; Barker, Edward D.; Tiemeier, Henning; van IJzendoorn, Marinus H.

2016-01-01

ABSTRACT Prenatal maternal stress exposure has been associated with neonatal differential DNA methylation. However, the available evidence in humans is largely based on candidate gene methylation studies, where only a few CpG sites were evaluated. The aim of this study was to examine the association between prenatal exposure to maternal stress and offspring genome-wide cord blood methylation using different methods. First, we conducted a meta-analysis and follow-up pathway analyses. Second, we used novel region discovery methods [i.e., differentially methylated regions (DMRs) analyses]. To this end, we used data from two independent population-based studies, the Generation R Study (n = 912) and the Avon Longitudinal Study of Parents and Children (ALSPAC, n = 828), to (i) measure genome-wide DNA methylation in cord blood and (ii) extract a prenatal maternal stress composite. The meta-analysis (ntotal = 1,740) revealed no epigenome-wide (meta P <1.00e-07) associations of prenatal maternal stress exposure with neonatal differential DNA methylation. Follow-up analyses of the top hits derived from our epigenome-wide meta-analysis (meta P <1.00e-04) indicated an over-representation of the methyltransferase activity pathway. We identified no Bonferroni-corrected (P <1.00e-06) DMRs associated with prenatal maternal stress exposure. Combining data from two independent population-based samples in an epigenome-wide meta-analysis, the current study indicates that there are no large effects of prenatal maternal stress exposure on neonatal DNA methylation. Such replication efforts are essential in the search for robust associations, whether derived from candidate gene methylation or epigenome-wide studies. PMID:26889969

NIOSH field studies team assessment: Worker exposure to aerosolized metal oxide nanoparticles in a semiconductor fabrication facility.

PubMed

Brenner, Sara A; Neu-Baker, Nicole M; Eastlake, Adrienne C; Beaucham, Catherine C; Geraci, Charles L

2016-11-01

The ubiquitous use of engineered nanomaterials-particulate materials measuring approximately 1-100 nanometers (nm) on their smallest axis, intentionally engineered to express novel properties-in semiconductor fabrication poses unique issues for protecting worker health and safety. Use of new substances or substances in a new form may present hazards that have yet to be characterized for their acute or chronic health effects. Uncharacterized or emerging occupational health hazards may exist when there is insufficient validated hazard data available to make a decision on potential hazard and risk to exposed workers under condition of use. To advance the knowledge of potential worker exposure to engineered nanomaterials, the National Institute for Occupational Safety and Health Nanotechnology Field Studies Team conducted an on-site field evaluation in collaboration with on-site researchers at a semiconductor research and development facility on April 18-21, 2011. The Nanomaterial Exposure Assessment Technique (2.0) was used to perform a complete exposure assessment. A combination of filter-based sampling and direct-reading instruments was used to identify, characterize, and quantify the potential for worker inhalation exposure to airborne alumina and amorphous silica nanoparticles associated with th e chemical mechanical planarization wafer polishing process. Engineering controls and work practices were evaluated to characterize tasks that might contribute to potential exposures and to assess existing engineering controls. Metal oxide structures were identified in all sampling areas, as individual nanoparticles and agglomerates ranging in size from 60 nm to >1,000 nm, with varying structure morphology, from long and narrow to compact. Filter-based samples indicated very little aerosolized material in task areas or worker breathing zone. Direct-reading instrument data indicated increased particle counts relative to background in the wastewater treatment area; however, particle counts were very low overall, indicating a well-controlled working environment. Recommendations for employees handling or potentially exposed to engineered nanomaterials include hazard communication, standard operating procedures, conservative ventilation systems, and prevention through design in locations where engineered nanomaterials are used or stored, and routine air sampling for occupational exposure assessment and analysis.

The mediating effect of mindful non-reactivity in exposure-based cognitive behavior therapy for severe health anxiety.

PubMed

Hedman, Erik; Hesser, Hugo; Andersson, Erik; Axelsson, Erland; Ljótsson, Brjánn

2017-08-01

Exposure-based cognitive behavior therapy (CBT) has been shown to be effective in the treatment of severe health anxiety, but little is known about mediators of treatment effect. The aim of the present study was to investigate mindful non-reactivity as a putative mediator of health anxiety outcome using data from a large scale randomized controlled trial. We assessed mindful non-reactivity using the Five Facets Mindfulness Questionnaire-Non-Reactivity scale (FFMQ-NR) and health anxiety with the Short Health Anxiety Inventory (SHAI). Participants with severe health anxiety (N=158) were randomized to internet-delivered exposure-based CBT or behavioral stress management (BSM) and throughout the treatment, both the mediator and outcome were measured weekly. As previously reported, exposure-based CBT was more effective than BSM in reducing health anxiety. In the present study, latent process growth modeling showed that treatment condition had a significant effect on the FFMQ-NR growth trajectory (α-path), estimate=0.18, 95% CI [0.04, 0.32], p=.015, indicating a larger increase in mindful non-reactivity among participants receiving exposure-based CBT compared to the BSM group. The FFMQ-NR growth trajectory was significantly correlated with the SHAI trajectory (β-path estimate=-1.82, 95% CI [-2.15, -1.48], p<.001. Test of the indirect effect, i.e. the estimated mediation effect (αβ) revealed a significant cross product of -0.32, which was statistically significant different from zero based on the asymmetric confidence interval method, 95% CI [-0.59, -0.06]. We conclude that increasing mindful non-reactivity may be of importance for achieving successful treatment outcomes in exposure-based CBT for severe health anxiety. Copyright © 2017 Elsevier Ltd. All rights reserved.

Developing physical exposure-based back injury risk models applicable to manual handling jobs in distribution centers.

PubMed

Lavender, Steven A; Marras, William S; Ferguson, Sue A; Splittstoesser, Riley E; Yang, Gang

2012-01-01

Using our ultrasound-based "Moment Monitor," exposures to biomechanical low back disorder risk factors were quantified in 195 volunteers who worked in 50 different distribution center jobs. Low back injury rates, determined from a retrospective examination of each company's Occupational Safety and Health Administration (OSHA) 300 records over the 3-year period immediately prior to data collection, were used to classify each job's back injury risk level. The analyses focused on the factors differentiating the high-risk jobs (those having had 12 or more back injuries/200,000 hr of exposure) from the low-risk jobs (those defined as having no back injuries in the preceding 3 years). Univariate analyses indicated that measures of load moment exposure and force application could distinguish between high (n = 15) and low (n = 15) back injury risk distribution center jobs. A three-factor multiple logistic regression model capable of predicting high-risk jobs with very good sensitivity (87%) and specificity (73%) indicated that risk could be assessed using the mean across the sampled lifts of the peak forward and or lateral bending dynamic load moments that occurred during each lift, the mean of the peak push/pull forces across the sampled lifts, and the mean duration of the non-load exposure periods. A surrogate model, one that does not require the Moment Monitor equipment to assess a job's back injury risk, was identified although with some compromise in model sensitivity relative to the original model.

Artificial Turf: Contested Terrains for Precautionary Public Health with Particular Reference to Europe?

PubMed Central

Watterson, Andrew

2017-01-01

Millions of adults, children and teenagers use artificial sports pitches and playgrounds globally. Pitches are artificial grass and bases may be made up of crumb rubber from recycled tires or new rubber and sand. Player injury on pitches was a major concern. Now, debates about health focus on possible exposure and uptake of chemicals within pitch and base materials. Research has looked at potential risks to users from hazardous substances such as metals, volatile organic compounds, polycyclic aromatic hydrocarbons including benzo (a) (e) pyrenes and phthalates: some are carcinogens and others may be endocrine disruptors and have developmental reproductive effects. Small environmental monitoring and modelling studies, often with significant data gaps about exposure, range of substances monitored, occupational exposures, types of surfaces monitored and study length across seasons, indicated little risk to sports people and children but some risk to installation workers. A few, again often small, studies indicated potentially harmful human effects relating to skin, respiration and cancers. Only one widely cited biomonitoring study has been done and no rigorous cancer epidemiological studies exist. Unravelling exposures and uptake over decades may prove complex. European regulators have strengthened controls over crumb rubber chemicals, set different standards for toys and crumb rubber pitches. Bigger US studies now underway attempting to fill some of the data gaps will report between 2017 and 2019. Public health professionals in the meantime may draw on established principles to support greater caution in setting crumb rubber exposure limits and controls. PMID:28895924

Stability of nonfouling electroless nickel-polytetrafluoroethylene coatings after exposure to commercial dairy equipment sanitizers.

PubMed

Huang, Kang; Goddard, Julie M

2015-09-01

Application of nonfouling coatings on thermal processing equipment can improve operational efficiency. However, to enable effective commercial translation, a need exists for more comprehensive studies on the stability of nonfouling coatings after exposure to different sanitizers. In the current study, the influence of different commercial dairy equipment sanitizers on the nonfouling properties of stainless steel modified with electroless Ni-polytetrafluoroethylene (PTFE) coatings was determined. Surface properties, such as dynamic contact angle, surface energy, surface morphology, and elemental composition, were measured before and after the coupons were exposed to the sanitizers for 168 cleaning cycles. The fouling behavior of Ni-PTFE-modified stainless steel coupons after exposure was also evaluated by processing raw milk on a self-fabricated benchtop-scale plate heat exchanger. The results indicated that peroxide sanitizer had only minor effect on the Ni-PTFE-modified stainless steel surface, whereas chlorine- and iodine-based sanitizers influenced the surface properties drastically. The coupons after 168 cycles of exposure to peroxide sanitizer accumulated the least amount of fouling material (4.44±0.24mg/cm(2)) compared with the coupons exposed to the other 3 sanitizers. These observations indicated that the Ni-PTFE nonfouling coating retained antifouling properties after 168 cycles of exposure to peroxide-based sanitizer, supporting their potential application as nonfouling coatings for stainless steel dairy processing equipment. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

A Web-based Tool to Aid the Identification of Chemicals Potentially Posing a Health Risk through Percutaneous Exposure.

PubMed

Gorman Ng, Melanie; Milon, Antoine; Vernez, David; Lavoué, Jérôme

2016-04-01

Occupational hygiene practitioners typically assess the risk posed by occupational exposure by comparing exposure measurements to regulatory occupational exposure limits (OELs). In most jurisdictions, OELs are only available for exposure by the inhalation pathway. Skin notations are used to indicate substances for which dermal exposure may lead to health effects. However, these notations are either present or absent and provide no indication of acceptable levels of exposure. Furthermore, the methodology and framework for assigning skin notation differ widely across jurisdictions resulting in inconsistencies in the substances that carry notations. The UPERCUT tool was developed in response to these limitations. It helps occupational health stakeholders to assess the hazard associated with dermal exposure to chemicals. UPERCUT integrates dermal quantitative structure-activity relationships (QSARs) and toxicological data to provide users with a skin hazard index called the dermal hazard ratio (DHR) for the substance and scenario of interest. The DHR is the ratio between the estimated 'received' dose and the 'acceptable' dose. The 'received' dose is estimated using physico-chemical data and information on the exposure scenario provided by the user (body parts exposure and exposure duration), and the 'acceptable' dose is estimated using inhalation OELs and toxicological data. The uncertainty surrounding the DHR is estimated with Monte Carlo simulation. Additional information on the selected substances includes intrinsic skin permeation potential of the substance and the existence of skin notations. UPERCUT is the only available tool that estimates the absorbed dose and compares this to an acceptable dose. In the absence of dermal OELs it provides a systematic and simple approach for screening dermal exposure scenarios for 1686 substances. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Sunlight exposure during leisure activities and risk of prostate cancer in Montréal, Canada, 2005-2009.

PubMed

Yu, Jennifer; Lavoué, Jérôme; Parent, Marie-Élise

2014-07-28

Prostate cancer (PCa) is the leading cause of cancer in men in many developed countries, but no modifiable risk factors have been identified. A handful of analytical studies have suggested a possible etiological role for sunlight exposure. We report here on the association between leisure-time sunlight exposure during adulthood and PCa risk in the context of a population-based case-control study. In all, 1,904 PCa cases were ascertained across Montreal French hospitals between 2005 and 2009. Concurrently, 1,962 population controls, frequency matched to cases by age (±5 years), were selected from the electoral list for French-speakers in Greater Montreal. Interviews elicited the frequency of engagement in any leisure activity during adulthood. This was used to derive cumulative sunlight exposure indices: a cumulative number of leisure activities events entailing sunlight exposure and a cumulative duration of sunlight exposure during leisure activities. Unconditional logistic regression was conducted to yield odds ratios (OR) and 95% confidence intervals (CI) for estimating the association between sunlight exposure indices and PCa risk, adjusting for age, ancestry, family history of PCa, PCa screening, education, solar protection, body mass index and physical activity. Compared with men in the upper quartile category for the number of sunlight exposure events, men never exposed during leisure time had an OR of 1.32 (95% CI: 0.82-2.14). ORs were 1.11, 0.91 and 1.00 for the first to the third quartiles of exposure, respectively. Similar results were observed for cumulative duration of exposure to sunlight, and by PCa aggressiveness. These findings provide little evidence of an association between sunlight exposure during leisure-time and PCa risk. Men with no sunlight exposure appeared at somewhat higher risks but none of the estimates achieved statistical significance.

Occupation and Thyroid Cancer

PubMed Central

Aschebrook-Kilfoy, Briseis; Ward, Mary H.; Valle, Curt T. Della; Friesen, Melissa C.

2014-01-01

Objectives Numerous occupational and environmental exposures have been shown to disrupt thyroid hormones, but much less is known about their relationships with thyroid cancer. Here we review the epidemiology studies of occupations and occupational exposures and thyroid cancer incidence to provide insight into preventable risk factors for thyroid cancer. Methods The published literature was searched using the Web of Knowledge database for all articles through August 2013 that had in their text “occupation” “job” ”employment” or “work” and “thyroid cancer”. After excluding 10 mortality studies and 4 studies with less than 5 exposed incident cases, we summarized the findings of 30 articles that examined thyroid cancer incidence in relation to occupations or occupational exposure. The studies were grouped by exposure/occupation category, study design, and exposure assessment approach. Where available, gender stratified results are reported. Results The most studied (19 of 30 studies) and the most consistent associations were observed for radiation-exposed workers and health care occupations. Suggestive, but inconsistent, associations were observed in studies of pesticide-exposed workers and agricultural occupations. Findings for other exposures and occupation groups were largely null. The majority of studies had few exposed cases and assessed exposure based on occupation or industry category, self-report, or generic (population-based) job exposure matrices. Conclusion The suggestive, but inconsistent findings for many of the occupational exposures reviewed here indicate that more studies with larger numbers of cases and better exposure assessment are necessary, particularly for exposures known to disrupt thyroid homeostasis. PMID:24604144

Investigation of the effects of long duration space exposure on active optical system components

NASA Technical Reports Server (NTRS)

Blue, M. D.

1994-01-01

This experiment was exposed to the space environment for 6 years on the Long Duration Exposure Facility (LDEF). It investigated quantitatively the effects of the long-duration space exposure on the relevant performance parameters of a representative set of electron-optic system components, including lasers, radiation detectors, filters, modulators, windows, and other related components. It evaluated the results and implications of the measurements indicating real or suspected degradation mechanisms. This information will be used to establish guidelines for the selection and use of components for space-based, electro-optic systems.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation

PubMed Central

Barberio, Amanda M; Hosein, F Shaun; Quiñonez, Carlos; McLaren, Lindsay

2017-01-01

Background There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. Methods We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. Results There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. Conclusion These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist. PMID:28839078

Comparing Data Input Requirements of Statistical vs. Process-based Watershed Models Applied for Prediction of Fecal Indicator and Pathogen Levels in Recreational Beaches

EPA Science Inventory

Same day prediction of fecal indicator bacteria (FIB) concentrations and bather protection from the risk of exposure to pathogens are two important goals of implementing a modeling program at recreational beaches. Sampling efforts for modelling applications can be expensive and t...

Trans-zygomatic middle cranial fossa approach to access lesions around the cavernous sinus and anterior parahippocampus: a minimally invasive skull base approach.

PubMed

Melamed, Itay; Tubbs, R Shane; Payner, Troy D; Cohen-Gadol, Aaron A

2009-08-01

Exposure of the cavernous sinus or anterior parahippocampus often involves a wide exposure of the temporal lobe and mobilization of the temporalis muscle associated with temporal lobe retraction. The authors present a cadaveric study to illustrate the feasibility, advantages and landmarks necessary to perform a trans-zygomatic middle fossa approach to lesions around the cavernous sinus and anterior parahippocampus. The authors performed bilateral trans-zygomatic middle fossae exposures to reach the cavernous sinus and parahippocampus in five cadavers (10 sides). We assessed the morbidity associated with this procedure and compared the indications, advantages, and disadvantages of this method versus more extensive skull base approaches. A vertical linear incision along the middle portion of the zygomatic arch was extended one finger breadth inferior to the inferior edge of the zygomatic arch. Careful dissection inferior to the arch allowed preservation of facial nerve branches. A zygomatic osteotomy was followed via a linear incision through the temporalis muscle and exposure of the middle cranial fossa floor. A craniotomy along the inferolateral temporal bone and middle fossa floor allowed extradural dissection along the middle fossa floor and exposure of the cavernous sinus including all three divisions of the trigeminal nerve. Intradural inspection demonstrated adequate exposure of the parahippocampus. Exposure of the latter required minimal or no retraction of the temporal lobe. The trans-zygomatic middle fossa approach is a simplified skull base exposure using a linear incision, which may avoid the invasivity of more extensive skull base approaches while providing an adequate corridor for resection of cavernous sinus and parahippocampus lesions. The advantages of this approach include its efficiency, ease, minimalism, preservation of the temporalis muscle, and minimal retraction of the temporal lobe.

Anemia risk in relation to lead exposure in lead-related manufacturing.

PubMed

Hsieh, Nan-Hung; Chung, Shun-Hui; Chen, Szu-Chieh; Chen, Wei-Yu; Cheng, Yi-Hsien; Lin, Yi-Jun; You, Su-Han; Liao, Chung-Min

2017-05-05

Lead-exposed workers may suffer adverse health effects under the currently regulated blood lead (BPb) levels. However, a probabilistic assessment about lead exposure-associated anemia risk is lacking. The goal of this study was to examine the association between lead exposure and anemia risk among factory workers in Taiwan. We first collated BPb and indicators of hematopoietic function data via health examination records that included 533 male and 218 female lead-exposed workers between 2012 and 2014. We used benchmark dose (BMD) modeling to estimate the critical effect doses for detection of abnormal indicators. A risk-based probabilistic model was used to characterize the potential hazard of lead poisoning for job-specific workers by hazard index (HI). We applied Bayesian decision analysis to determine whether BMD could be implicated as a suitable BPb standard. Our results indicated that HI for total lead-exposed workers was 0.78 (95% confidence interval: 0.50-1.26) with risk occurrence probability of 11.1%. The abnormal risk of anemia indicators for male and female workers could be reduced, respectively, by 67-77% and 86-95% by adopting the suggested BPb standards of 25 and 15 μg/dL. We conclude that cumulative exposure to lead in the workplace was significantly associated with anemia risk. This study suggests that current BPb standard needs to be better understood for the application of lead-exposed population protection in different scenarios to provide a novel standard for health management. Low-level lead exposure risk is an occupational and public health problem that should be paid more attention.

Combining near- and far-field exposure for an organ-specific and whole-body RF-EMF proxy for epidemiological research: a reference case.

PubMed

Lauer, Oliver; Frei, Patrizia; Gosselin, Marie-Christine; Joseph, Wout; Röösli, Martin; Fröhlich, Jürg

2013-07-01

A framework for the combination of near-field (NF) and far-field (FF) radio frequency electromagnetic exposure sources to the average organ and whole-body specific absorption rates (SARs) is presented. As a reference case, values based on numerically derived SARs for whole-body and individual organs and tissues are combined with realistic exposure data, which have been collected using personal exposure meters during the Swiss Qualifex study. The framework presented can be applied to any study region where exposure data is collected by appropriate measurement equipment. Based on results derived from the data for the region of Basel, Switzerland, the relative importance of NF and FF sources to the personal exposure is examined for three different study groups. The results show that a 24-h whole-body averaged exposure of a typical mobile phone user is dominated by the use of his or her own mobile phone when a Global System for Mobile Communications (GSM) 900 or GSM 1800 phone is used. If only Universal Mobile Telecommunications System (UMTS) phones are used, the user would experience a lower exposure level on average caused by the lower average output power of UMTS phones. Data presented clearly indicate the necessity of collecting band-selective exposure data in epidemiological studies related to electromagnetic fields. Copyright © 2013 Wiley Periodicals, Inc.

Speciation of airborne dust from a nickel refinery roasting operation.

PubMed

Andersen, I; Berge, S R; Resmann, F

1998-04-01

Earlier work-related lung and nasal cancer studies included estimates of exposures to different nickel species in the refinery. Based on the metallurgy, only insoluble nickel was believed to be present around the roasters but mixed exposure was assumed in most areas, including the tankhouse. Occasional leaching tests of samples from the roaster area have indicated the presence of soluble nickel. This study reports on five parallel sets of dust samples collected from different floors with standard equipment and treated as follows. Two sets were leached with an ammonium citrate buffer at pH 4.4. Undissolved material was treated with HClO4/HNO3, evaporated to dryness and dissolved in HCl, Ni, Cu, Co, Fe, Se, and As were determined in both fractions. Water soluble Ni was found in all samples, ranging from 5-35%. Sulfate in the solutions correlated nearly stoichiometrically to the total metal content. The three remaining sets were investigated by, respectively, differential leaching, X-ray diffraction and scanning electron microscopy. The percentage of soluble nickel found by differential leaching corresponded well with those obtained by the simplified procedure. X-Ray diffraction analysis showed the presence of NiSO4.6H2O as well as oxides of Ni and Cu. This study indicates mixed exposures also in the roaster area. It also clearly indicates that basing exposure on the metallurgy alone can lead to serious misjudgements. The impact of this new information on the interpretation of cancer incidence at this refinery must await the analysis in an ongoing case-reference study.

A higher sink competitiveness of the rooting zone and invertases are involved in dark stimulation of adventitious root formation in Petunia hybrida cuttings.

PubMed

Klopotek, Yvonne; Franken, Philipp; Klaering, Hans-Peter; Fischer, Kerstin; Hause, Bettina; Hajirezaei, Mohammad-Reza; Druege, Uwe

2016-02-01

The contribution of carbon assimilation and allocation and of invertases to the stimulation of adventitious root formation in response to a dark pre-exposure of petunia cuttings was investigated, considering the rooting zone (stem base) and the shoot apex as competing sinks. Dark exposure had no effect on photosynthesis and dark respiration during the subsequent light period, but promoted dry matter partitioning to the roots. Under darkness, higher activities of cytosolic and vacuolar invertases were maintained in both tissues when compared to cuttings under light. This was partially associated with higher RNA levels of respective genes. However, activity of cell wall invertases and transcript levels of one cell wall invertase isogene increased specifically in the stem base during the first two days after cutting excision under both light and darkness. During five days after excision, RNA accumulation of four invertase genes indicated preferential expression in the stem base compared to the apex. Darkness shifted the balance of expression of one cytosolic and two vacuolar invertase genes towards the stem base. The results indicate that dark exposure before planting enhances the carbon sink competitiveness of the rooting zone and that expression and activity of invertases contribute to the shift in carbon allocation. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

Is benzene exposure from gasoline carcinogenic?

PubMed

Jamall, Ijaz S; Willhite, Calvin C

2008-02-01

This article questions the basis for benzene as the carcinogenic surrogate in deriving health risk-based 'clean-up levels' for gasoline-impacted soil and groundwater at leaking underground storage tank properties. The epidemiological evidence suggests that acute myelogenous leukemia (AML) associated with chronic occupational benzene exposure can be best described by sigmoid dose-response relationships. A review of the molecular toxicology and kinetics of benzene points to the existence of threshold mechanisms in the induction of leukemia. The toxicological and epidemiological literature on chronic exposure to unleaded gasoline indicates that the benzene exposures required to induce a measurable carcinogenic response are substantially greater than exposures likely to be encountered from exposure to gasoline at contaminated properties. Thus, assuming that theoretical cancer risks associated with exposure to benzene from gasoline reflect actual health risks associated with such environmental exposures to gasoline and using these theoretical cancer risks and cancer potency factors for benzene to dictate soil and groundwater clean up of gasoline are not scientifically defensible.

A case-control study of airways obstruction among construction workers: Airways Obstruction Among Construction Workers

DOE PAGES

Dement, John; Welch, Laura; Ringen, Knut; ...

2015-06-29

Background: While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case-control study estimated the risk of COPD attributable to occupational exposures among construction workers. Methods: The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories. Results: Approximately 18% (95%CI=2–24%) of COPD risk can be attributed to construction-related exposures, which are additive to the risk contributed by smoking. Amore » measure of all VGDF exposures combined was a strong predictor of COPD risk. Conclusions: Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted« less

Comparing children's GPS tracks with geospatial proxies for exposure to junk food.

PubMed

Sadler, Richard C; Gilliland, Jason A

2015-01-01

Various geospatial techniques have been employed to estimate children's exposure to environmental cardiometabolic risk factors, including junk food. But many studies uncritically rely on exposure proxies which differ greatly from actual exposure. Misrepresentation of exposure by researchers could lead to poor decisions and ineffective policymaking. This study conducts a GIS-based analysis of GPS tracks--'activity spaces'--and 21 proxies for activity spaces (e.g. buffers, container approaches) for a sample of 526 children (ages 9-14) in London, Ontario, Canada. These measures are combined with a validated food environment database (including fast food and convenience stores) to create a series of junk food exposure estimates and quantify the errors resulting from use of different proxy methods. Results indicate that exposure proxies consistently underestimate exposure to junk foods by as much as 68%. This underestimation is important to policy development because children are exposed to more junk food than estimated using typical methods. Copyright © 2015 Elsevier Ltd. All rights reserved.

A case-control study of airways obstruction among construction workers: Airways Obstruction Among Construction Workers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dement, John; Welch, Laura; Ringen, Knut

Background: While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case-control study estimated the risk of COPD attributable to occupational exposures among construction workers. Methods: The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories. Results: Approximately 18% (95%CI=2–24%) of COPD risk can be attributed to construction-related exposures, which are additive to the risk contributed by smoking. Amore » measure of all VGDF exposures combined was a strong predictor of COPD risk. Conclusions: Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted« less

A case-control study of airways obstruction among construction workers.

PubMed

Dement, John; Welch, Laura; Ringen, Knut; Quinn, Patricia; Chen, Anna; Haas, Scott

2015-10-01

While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case-control study estimated the risk of COPD attributable to occupational exposures among construction workers. The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories. Approximately 18% (95% CI = 2-24%) of COPD risk can be attributed to construction-related exposures, which are additive to the risk contributed by smoking. A measure of all VGDF exposures combined was a strong predictor of COPD risk. Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted. © 2015 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc.

What to expect from immersive virtual environment exposure: influences of gender, body mass index, and past experience.

PubMed

Stanney, Kay M; Hale, Kelly S; Nahmens, Isabelina; Kennedy, Robert S

2003-01-01

For those interested in using head-coupled PC-based immersive virtual environment (VE) technology to train, entertain, or inform, it is essential to understand the effects this technology has on its users. This study investigated potential adverse effects, including the sickness associated with exposure and extreme responses (emesis, flashbacks). Participants were exposed to a VE for 15 to 60 min, with either complete or streamlined navigational control and simple or complex scenes, after which time measures of sickness were obtained. More than 80% of participants experienced nausea, oculomotor disturbances, and/or disorientation, with disorientation potentially lasting > 24 hr. Of the participants, 12.9% prematurely ended their exposure because of adverse effects; of these, 9.2% experienced an emetic response, whereas only 1.2% of all participants experienced emesis. The results indicate that designers may be able to reduce these rates by limiting exposure duration and reducing the degrees of freedom of the user's navigational control. Results from gender, body mass, and past experience comparisons indicated it may be possible to identify those who will experience adverse effects attributable to exposure and warn such individuals. Applications for this research include military, entertainment, and any other interactive systems for which designers seek to avoid adverse effects associated with exposure.

Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska

NASA Astrophysics Data System (ADS)

Bowen, Lizabeth; Miles, A. Keith; Ballachey, Brenda; Waters, Shannon; Bodkin, James; Lindeberg, Mandy; Esler, Daniel

2018-01-01

The 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant levels are low and chronic. Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess chronic oil contamination using the Pacific blue mussel, Mytilus trossulus. We developed a diagnostic gene transcription panel to investigate exposure to PAHs and other contaminants and its effects on mussel physiology and health. During 2012-2015, we analyzed mussels from five field sites in western Prince William Sound, Alaska, with varying oil histories from the 1989 Exxon Valdez oil spill, and from three boat harbors in the area. Gene transcription patterns of mussels from harbors were consistent with elevated exposure to PAHs or other contaminants, whereas transcription patterns of mussels sampled from shorelines in areas affected by the oil spill indicated no PAH exposure.

Moringa oleifera-based diet protects against nickel-induced hepatotoxicity in rats.

PubMed

Stephen Adeyemi, Oluyomi; Sokolayemji Aroge, Cincin; Adewumi Akanji, Musbau

2017-07-13

Multiple health-promoting effects have been attributed to the consumption of Moringa oleifera leaves, as part of diet without adequate scientific credence. This study evaluated the effect of M. oleifera-based diets on nickel (Ni) - induced hepatotoxicity in rats. Male rats assigned into six groups were given oral administration of 20 mg/kg body weight nickel sulfate in normal saline and either fed normal diet orM. oleifera-based diets for 21 days. All animals were sacrificed under anesthesia 24 hours after the last treatment. Ni exposure elevated the rat plasma activities of alanine transaminase, aspartate transaminase and alkaline phosphatase significantly. Ni exposure also raised the levels of triglyceride, total cholesterol and low-density lipoprotein cholesterol while depleting the high-density lipoprotein cholesterol concentration. Further, Ni exposure raised rat plasma malondialdehyde but depleted reduced glutathione concentrations. The histopathological presentations revealed inflammation and cellular degeneration caused by Ni exposure. We show evidence thatM. oleifera-based diets protected against Ni-induced hepatotoxicity by improving the rat liver function indices, lipid profile as well as restoring cellular architecture and integrity. Study lends credence to the health-promoting value ofM. oleifera as well as underscores its potential to attenuate hepatic injury.

Recreational use assessment of water-based activities, using time-lapse construction cameras.

PubMed

Sunger, Neha; Teske, Sondra S; Nappier, Sharon; Haas, Charles N

2012-01-01

Recreational exposure to surface waters during periods of increased pathogen concentration may lead to a significantly higher risk of illness. However, estimates of elementary exposure factors necessary to evaluate health risk (i.e., usage distributions and exposure durations) are not available for many non-swimming water-related activities. No prior studies have assessed non-swimming water exposure with respect to factors leading to impaired water quality from increased pathogen concentration, such as weather condition (rain events produce increased runoff and sewer overflows) and type of day (heavy recreational periods). We measured usage patterns and evaluated the effect of weather and type of day at eight water sites located within Philadelphia, by using a novel "time lapse photography" technology during three peak recreational seasons (May-September) 2008-2010. Camera observations validated with simultaneous in-person surveys exhibited a strong correlation (R(2)=0.81 to 0.96) between the two survey techniques, indicating that the application of remote photography in collecting human exposure data was appropriate. Recreational activities usage varied more on a temporal basis than due to inclement weather. Only 14% (6 out of 44) of the site-specific activity combinations showed dry weather preference, whereas 41.5% (17 out of 41) of the combinations indicated greater usage on weekends as compared with weekday. In general, the log normal distribution described the playing and wading duration distribution, while the gamma distribution was the best fit for fishing durations. Remote photography provided unbiased, real-time human exposure data and was less personnel intensive compared with traditional survey methods. However, there are potential limitations associated with remote surveillance data related to its limited view. This is the first study to report that time lapse cameras can be successfully applied to assess water-based human recreational patterns and can provide precise exposure statistics for non-swimming recreational exposures.

Assessing the safety of co-exposure to food packaging migrants in food and water using the maximum cumulative ratio and an established decision tree.

PubMed

Price, Paul; Zaleski, Rosemary; Hollnagel, Heli; Ketelslegers, Hans; Han, Xianglu

2014-01-01

Food contact materials can release low levels of multiple chemicals (migrants) into foods and beverages, to which individuals can be exposed through food consumption. This paper investigates the potential for non-carcinogenic effects from exposure to multiple migrants using the Cefic Mixtures Ad hoc Team (MIAT) decision tree. The purpose of the assessment is to demonstrate how the decision tree can be applied to concurrent exposures to multiple migrants using either hazard or structural data on the specific components, i.e. based on the acceptable daily intake (ADI) or the threshold of toxicological concern. The tree was used to assess risks from co-exposure to migrants reported in a study on non-intentionally added substances (NIAS) eluting from food contact-grade plastic and two studies of water bottles: one on organic compounds and the other on ionic forms of various elements. The MIAT decision tree assigns co-exposures to different risk management groups (I, II, IIIA and IIIB) based on the hazard index, and the maximum cumulative ratio (MCR). The predicted co-exposures for all examples fell into Group II (low toxicological concern) and had MCR values of 1.3 and 2.4 (indicating that one or two components drove the majority of the mixture's toxicity). MCR values from the study of inorganic ions (126 mixtures) ranged from 1.1 to 3.8 for glass and from 1.1 to 5.0 for plastic containers. The MCR values indicated that a single compound drove toxicity in 58% of the mixtures. MCR values also declined with increases in the hazard index for the screening assessments of exposure (suggesting fewer substances contributed as risk potential increased). Overall, it can be concluded that the data on co-exposure to migrants evaluated in these case studies are of low toxicological concern and the safety assessment approach described in this paper was shown to be a helpful screening tool.

A non-inferiority trial of Prolonged Exposure for posttraumatic stress disorder: In person versus home-based telehealth.

PubMed

Acierno, Ron; Knapp, Rebecca; Tuerk, Peter; Gilmore, Amanda K; Lejuez, Carl; Ruggiero, Kenneth; Muzzy, Wendy; Egede, Leonard; Hernandez-Tejada, Melba A; Foa, Edna B

2017-02-01

This is the first randomized controlled trial to evaluate non-inferiority of Prolonged Exposure (PE) delivered via home-based telehealth (HBT) compared to standard in-person (IP) PE. One-hundred thirty two Veterans recruited from a Southeastern Veterans Affairs Medical Center and affiliated University who met criteria for posttraumatic stress disorder (PTSD) were randomized to receive PE via HBT or PE via IP. Results indicated that PE-HBT was non-inferior to PE-IP in terms of reducing PTSD scores at post-treatment, 3 and 6 month follow-up. However, non-inferiority hypotheses for depression were only supported at 6 month follow-up. HBT has great potential to reduce patient burden associated with receiving treatment in terms of travel time, travel cost, lost work, and stigma without sacrificing efficacy. These findings indicate that telehealth treatment delivered directly into patients' homes may dramatically increase the reach of this evidence-based therapy for PTSD without diminishing effectiveness. Published by Elsevier Ltd.

The 737 graphite composite flight spoiler flight service evaluation

NASA Technical Reports Server (NTRS)

Hoffman, D. J.; Stoecklin, R. L.

1980-01-01

The flight service experience of 111 graphite-epoxy spoilers on 737 transport aircraft and related ground based enviromental exposure of graphite-epoxy material specimens is reported. Spoilers were installed on 28 aircraft representing seven major airlines operating throughout the world. Over 1,188,367 spoiler flight hours and 1,786,837 spoiler landings were accumulated by this fleet. Tests of removed spoilers and ground-based exposure specimens after the fifth year of service indicate modest changes in composite strength properties. Two incidents of trailing edge delamination with subsequent core corrosion were observed. Based on visual, ultrasonic, and destructive testing, there has been no evidence of moisture migration into the honeycomb core and no core corrosion.

Carbon dioxide induced plasticity of branchial acid-base pathways in an estuarine teleost

PubMed Central

Allmon, Elizabeth B.; Esbaugh, Andrew J.

2017-01-01

Anthropogenic CO2 is expected to drive ocean pCO2 above 1,000 μatm by 2100 – inducing respiratory acidosis in fish that must be corrected through branchial ion transport. This study examined the time course and plasticity of branchial metabolic compensation in response to varying levels of CO2 in an estuarine fish, the red drum, which regularly encounters elevated CO2 and may therefore have intrinsic resilience. Under control conditions fish exhibited net base excretion; however, CO2 exposure resulted in a dose dependent increase in acid excretion during the initial 2 h. This returned to baseline levels during the second 2 h interval for exposures up to 5,000 μatm, but remained elevated for exposures above 15,000 μatm. Plasticity was assessed via gene expression in three CO2 treatments: environmentally realistic 1,000 and 6,000 μatm exposures, and a proof-of-principle 30,000 μatm exposure. Few differences were observed at 1,000 or 6,000 μatm; however, 30,000 μatm stimulated widespread up-regulation. Translocation of V-type ATPase after 1 h of exposure to 30,000 μatm was also assessed; however, no evidence of translocation was found. These results indicate that red drum can quickly compensate to environmentally relevant acid-base disturbances using baseline cellular machinery, yet are capable of plasticity in response to extreme acid-base challenges. PMID:28378831

Carbon dioxide induced plasticity of branchial acid-base pathways in an estuarine teleost

NASA Astrophysics Data System (ADS)

Allmon, Elizabeth B.; Esbaugh, Andrew J.

2017-04-01

Anthropogenic CO2 is expected to drive ocean pCO2 above 1,000 μatm by 2100 - inducing respiratory acidosis in fish that must be corrected through branchial ion transport. This study examined the time course and plasticity of branchial metabolic compensation in response to varying levels of CO2 in an estuarine fish, the red drum, which regularly encounters elevated CO2 and may therefore have intrinsic resilience. Under control conditions fish exhibited net base excretion; however, CO2 exposure resulted in a dose dependent increase in acid excretion during the initial 2 h. This returned to baseline levels during the second 2 h interval for exposures up to 5,000 μatm, but remained elevated for exposures above 15,000 μatm. Plasticity was assessed via gene expression in three CO2 treatments: environmentally realistic 1,000 and 6,000 μatm exposures, and a proof-of-principle 30,000 μatm exposure. Few differences were observed at 1,000 or 6,000 μatm however, 30,000 μatm stimulated widespread up-regulation. Translocation of V-type ATPase after 1 h of exposure to 30,000 μatm was also assessed; however, no evidence of translocation was found. These results indicate that red drum can quickly compensate to environmentally relevant acid-base disturbances using baseline cellular machinery, yet are capable of plasticity in response to extreme acid-base challenges.

How TK-TD and population models for aquatic macrophytes could support the risk assessment for plant protection products.

PubMed

Hommen, Udo; Schmitt, Walter; Heine, Simon; Brock, Theo Cm; Duquesne, Sabine; Manson, Phil; Meregalli, Giovanna; Ochoa-Acuña, Hugo; van Vliet, Peter; Arts, Gertie

2016-01-01

This case study of the Society of Environmental Toxicology and Chemistry (SETAC) workshop MODELINK demonstrates the potential use of mechanistic effects models for macrophytes to extrapolate from effects of a plant protection product observed in laboratory tests to effects resulting from dynamic exposure on macrophyte populations in edge-of-field water bodies. A standard European Union (EU) risk assessment for an example herbicide based on macrophyte laboratory tests indicated risks for several exposure scenarios. Three of these scenarios are further analyzed using effect models for 2 aquatic macrophytes, the free-floating standard test species Lemna sp., and the sediment-rooted submerged additional standard test species Myriophyllum spicatum. Both models include a toxicokinetic (TK) part, describing uptake and elimination of the toxicant, a toxicodynamic (TD) part, describing the internal concentration-response function for growth inhibition, and a description of biomass growth as a function of environmental factors to allow simulating seasonal dynamics. The TK-TD models are calibrated and tested using laboratory tests, whereas the growth models were assumed to be fit for purpose based on comparisons of predictions with typical growth patterns observed in the field. For the risk assessment, biomass dynamics are predicted for the control situation and for several exposure levels. Based on specific protection goals for macrophytes, preliminary example decision criteria are suggested for evaluating the model outputs. The models refined the risk indicated by lower tier testing for 2 exposure scenarios, while confirming the risk associated for the third. Uncertainties related to the experimental and the modeling approaches and their application in the risk assessment are discussed. Based on this case study and the assumption that the models prove suitable for risk assessment once fully evaluated, we recommend that 1) ecological scenarios be developed that are also linked to the exposure scenarios, and 2) quantitative protection goals be set to facilitate the interpretation of model results for risk assessment. © 2015 SETAC.

Mesh versus bathtub - effects of flood models on exposure analysis in Switzerland

NASA Astrophysics Data System (ADS)

Röthlisberger, Veronika; Zischg, Andreas; Keiler, Margreth

2016-04-01

In Switzerland, mainly two types of maps that indicate potential flood zones are available for flood exposure analyses: 1) Aquaprotect, a nationwide overview provided by the Federal Office for the Environment and 2) communal flood hazard maps available from the 26 cantons. The model used to produce Aquaprotect can be described as a bathtub approach or linear superposition method with three main parameters, namely the horizontal and vertical distance of a point to water features and the size of the river sub-basin. Whereas the determination of flood zones in Aquaprotect is based on a uniform, nationwide model, the communal flood hazard maps are less homogenous, as they have been elaborated either at communal or cantonal levels. Yet their basic content (i.e. indication of potential flood zones for three recurrence periods, with differentiation of at least three inundation depths) is described in national directives and the vast majority of communal flood hazard maps are based on 2D inundation simulations using meshes. Apart from the methodical differences between Aquaprotect and the communal flood hazard maps (and among different communal flood hazard maps), all of these maps include a layer with a similar recurrence period (i.e. Aquaprotect 250 years, flood hazard maps 300 years) beyond the intended protection level of installed structural systems. In our study, we compare the resulting exposure by overlaying the two types of flood maps with a complete, harmonized, and nationwide dataset of building polygons. We assess the different exposure at the national level, and also consider differences among the 26 cantons and the six biogeographically unique regions, respectively. It was observed that while the nationwide exposure rates for both types of flood maps are similar, the differences within certain cantons and biogeographical regions are remarkable. We conclude that flood maps based on bathtub models are appropriate for assessments at national levels, while maps based on 2D simulations are preferable at sub-national levels.

Cyberbullying behavior and adolescents' use of media with antisocial content: a cyclic process model.

PubMed

den Hamer, Anouk; Konijn, Elly A; Keijer, Micha G

2014-02-01

The present study examined the role of media use in adolescents' cyberbullying behavior. Following previous research, we propose a Cyclic Process Model of face-to-face victimization and cyberbullying through two mediating processes of anger/frustration and antisocial media content. This model was tested utilizing a cross-sectional design with adolescent participants (N=892). Exposure to antisocial media content was measured with a newly developed content-based scale (i.e., the C-ME), showing good psychometric qualities. Results of structural equation modeling showed that adolescents' exposure to antisocial media content was significantly associated with cyberbullying behavior, especially in adolescents who experienced anger and frustration due to face-to-face victimization. Goodness of fit indices demonstrated a good fit of the theoretical model to the data and indicated that exposure to antisocial media content acts as an amplifier in a cyclic process of victimization-related anger and cyberbullying behavior.

Childhood leukemia and magnetic fields in infant incubators.

PubMed

Söderberg, Karin C; Naumburg, Estelle; Anger, Gert; Cnattingius, Sven; Ekbom, Anders; Feychting, Maria

2002-01-01

In studies of magnetic field exposure and childhood leukemia, power lines and other electrical installations close to the children's homes constitute the most extensively studied source of exposure. We conducted a study to assess whether exposure to magnetic fields in infant incubators is associated with an increased leukemia risk. We identified all children with leukemia born in Sweden between 1973 and 1989 from the national Cancer Registry and selected at random one control per case, individually matched by sex and time of birth, from the study base. We retrieved information about treatment in infant incubators from medical records. We made measurements of the magnetic fields inside the incubators for each incubator model kept by the hospitals. Exposure assessment was based on measurements of the magnetic field level inside the incubator, as well as on the length of treatment. For acute lymphoblastic leukemia, the risk estimates were close to unity for all exposure definitions. For acute myeloid leukemia, we found a slightly elevated risk, but with wide confidence intervals and with no indication of dose response. Overall, our results give little evidence that exposure to magnetic fields inside infant incubators is associated with an increased risk of childhood leukemia.

Copper-Based Aquatic Algaecide Adsorption and Accumulation Kinetics: Influence of Exposure Concentration and Duration for Controlling the Cyanobacterium Lyngbya wollei.

PubMed

Bishop, West M; Lynch, Clayton L; Willis, Ben E; Cope, W Gregory

2017-09-01

Filamentous mat-forming cyanobacteria are increasingly impairing uses of freshwater resources. To effectively manage, a better understanding of control measures is needed. Copper (Cu)-based algaecide formulations are often applied to reactively control nuisance cyanobacterial blooms. This laboratory research assessed typical field exposure scenarios for the ability of Cu to partition to, and accumulate in Lyngbya wollei. Exposure factors (Cu concentration × duration) of 4, 8, 16, 24, 32 h were tested across three aqueous Cu concentrations (1, 2, 4 ppm). Results indicated that internally accumulated copper correlated with control of L. wollei, independent of adsorbed copper. L. wollei control was determined by filament viability and chlorophyll a concentrations. Similar exposure factors elicited similar internalized copper levels and consequent responses of L. wollei. Ultimately, a "concentration-exposure-time" (CET) model was created to assist water resource managers in selecting an appropriate treatment regime for a specific in-water infestation. By assessing the exposure concentration and duration required to achieve the internal threshold of copper (i.e., critical burden) that elicits control, water management objectives can be achieved while simultaneously decreasing the environmental loading of copper and potential for non-target species risks.

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

PubMed

Valcke, Mathieu; Haddad, Sami

2015-01-01

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

Portal imaging with flat-panel detector and CCD camera

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Tang, Chuankun; Cheng, Chee-Wai; Dallas, William J.

1997-07-01

This paper provides a comparison of imaging parameters of two portal imaging systems at 6 MV: a flat panel detector and a CCD-camera based portal imaging system. Measurements were made of the signal and noise and consequently of signal-to-noise per pixel as a function of the exposure. Both systems have a linear response with respect to exposure, and the noise is proportional to the square-root of the exposure, indicating photon-noise limitation. The flat-panel detector has a signal- to-noise ratio, which is higher than that observed wit the CCD-camera based portal imaging system. This is expected because most portal imaging systems using optical coupling with a lens exhibit severe quantum-sinks. The paper also presents data on the screen's photon gain (the number of light-photons per interacting x-ray photon), as well as on the magnitude of the Swank-noise, (which describes fluctuation in the screen's photon gain). Images of a Las Vegas-type aluminum contrast detail phantom, located at the ISO-Center, were generated at an exposure of 1 MU. The CCD-camera based system permits detection of aluminum-holes of 0.01194 cm diameter and 0.228 mm depth while the flat-panel detector permits detection of aluminum holes of 0.01194 cm diameter and 0.1626 mm depth, indicating a better signal-to-noise ratio. Rank order filtering was applied to the raw images from the CCD-based system in order to remove the direct hits. These are camera responses to scattered x-ray photons which interact directly with the CCD of the CCD-camera and generate 'salt and pepper type noise,' which interferes severely with attempts to determine accurate estimates of the image noise.

Population Pharmacokinetics and Exposure Response Assessment of CC-292, a Potent BTK Inhibitor, in Patients With Chronic Lymphocytic Leukemia.

PubMed

Li, Yan; Ramírez-Valle, Francisco; Xue, Yongjun; Ventura, Judith I; Gouedard, Olivier; Mei, Jay; Takeshita, Kenichi; Palmisano, Maria; Zhou, Simon

2017-10-01

CC-292, a potent Bruton tyrosine kinase inhibitor, is under development for the treatment of B-cell malignancies. An analysis was performed to develop a population pharmacokinetic model of CC-292 and assess the influence of demographics and disease-related covariates on CC-292 exposure and to assess the exposure-response (overall response rate) relationship in patients with chronic lymphocytic leukemia. Population pharmacokinetic analysis was based on a 2-compartment base model conducted in NONMEM. Categorical exposure-response analysis was performed using logistic regression in SAS. The population pharmacokinetic analysis results indicated that CC-292 pharmacokinetic disposition is similar between healthy subjects and patients. CC-292 showed a larger central compartment volume of distribution than the peripheral compartment volume of distribution (158 L and 72 L, respectively) and a faster clearance than intercompartmental clearance (134 L/h and 18.7 L/h, respectively), indicating that for CC-292, clearance from blood occurs faster than distribution into deep tissues and organs. CC-292 clearance is not affected by demographics or baseline clinical lab factors, except for sex. Although sex significantly reduced variation of apparent clearance, the sex effect on apparent clearance is unlikely to be clinically relevant. The exposure-response analysis suggested that higher drug exposure is linearly correlated with higher overall response rate. A twice-daily dose regimen showed higher overall response rate as compared to once-daily dosing, consistent with a threshold concentration of approximately 300 ng/mL, above which the probability of overall response rate significantly increases. © 2017, The Authors. The Journal of Clinical Pharmacology Published by Wiley Periodicals, Inc. on behalf of American College of Clinical Pharmacology.

Genetic damage in human cells exposed to non-ionizing radiofrequency fields: a meta-analysis of the data from 88 publications (1990-2011).

PubMed

Vijayalaxmi; Prihoda, Thomas J

2012-12-12

Based on the 'limited' evidence suggesting an association between exposure to radiofrequency fields (RF) emitted from mobile phones and two types of brain cancer, glioma and acoustic neuroma, the International Agency for Research on Cancer has classified RF as 'possibly carcinogenic to humans' in group 2B. In view of this classification and the positive correlation between increased genetic damage and carcinogenesis, a meta-analysis was conducted to determine whether a significant increase in genetic damage in human cells exposed to RF provides a potential mechanism for its carcinogenic potential. The extent of genetic damage in human cells, assessed from various end-points, viz., single-/double-strand breaks in the DNA, incidence of chromosomal aberrations, micronuclei and sister chromatid exchanges, reported in a total of 88 peer-reviewed scientific publications during 1990-2011 was considered in the meta-analysis. Among the several variables in the experimental protocols used, the influence of five specific variables related to RF exposure characteristics was investigated: (i) frequency, (ii) specific absorption rate, (iii) exposure as continuous wave, pulsed wave and occupationally exposed/mobile phone users, (iv) duration of exposure, and (v) different cell types. The data indicated the following. (1) The magnitude of difference between RF-exposed and sham-/un-exposed controls was small with some exceptions. (2) In certain RF exposure conditions there was a statistically significant increase in genotoxicity assessed from some end-points: the effect was observed in studies with small sample size and was largely influenced by publication bias. Studies conducted within the generally recommended RF exposure guidelines showed a smaller effect. (3) The multiple regression analyses and heterogeneity goodness of fit data indicated that factors other than the above five variables as well as the quality of publications have contributed to the overall results. (4) More importantly, the mean indices for chromosomal aberrations, micronuclei and sister chromatid exchange end-points in RF-exposed and sham-/un-exposed controls were within the spontaneous levels reported in a large data-base. Thus, the classification of RF as possibly carcinogenic to humans in group 2B was not supported by genotoxicity-based mechanistic evidence. Copyright © 2012 Elsevier B.V. All rights reserved.

Human serum miR-34a as an indicator of exposure to ionizing radiation.

PubMed

Halimi, Mohammad; Shahabi, Ahmad; Moslemi, Dariush; Parsian, Hadi; Asghari, S Mohsen; Sariri, Reyhaneh; Yeganeh, Farshid; Zabihi, Ebrahim

2016-11-01

Radiation exposure in industrial accidents or nuclear device attacks is a major public health concern. There is an urgent need for markers that rapidly identify people exposed to ionizing radiation (IR). Finding a blood-based marker is advantageous because of the ease of sample collection. This study was designed to test the hypothesis that serum miR-34a could serve as an indicator of exposure to IR. Therefore, 44 women with breast cancer, where radiotherapy was part of their therapeutic protocol, were investigated in this study. After demonstrating the appropriateness of our microRNA (miRNA) extraction efficiency and miRNA assay in human serum, we analyzed the miR-34a level in paired serum samples before and after radiotherapy. Fifty Gy X-ray irradiation in daily dose fractions of 2 Gy, 5 days per week, was used in this study. We demonstrated that IR significantly increased serum level of miR-34a. By measuring miR-34a in serum, we could distinguish irradiated patients with sensitivity of 65 % and specificity of 75 %. According to this study, serum miR-34a has the potential to be used as an indicator of radiation exposure.

Vaccinating women previously exposed to human papillomavirus: a cost-effectiveness analysis of the bivalent vaccine.

PubMed

Turner, Hugo C; Baussano, Iacopo; Garnett, Geoff P

2013-01-01

Recent trials have indicated that women with prior exposure to Human papillomavirus (HPV) subtypes 16/18 receive protection against reinfection from the HPV vaccines. However, many of the original models investigating the cost effectiveness of different vaccination strategies for the protection of cervical cancer assumed, based on the trial results at that time, that these women received no protection. We developed a deterministic, dynamic transmission model that incorporates the vaccine-induced protection of women with prior exposure to HPV. The model was used to estimate the cost effectiveness of progressively extending a vaccination programme using the bivalent vaccine to older age groups both with and without protection of women with prior exposure. We did this under a range of assumptions on the level of natural immunity. Our modelling projections indicate that including the protection of women with prior HPV exposure can have a profound effect on the cost effectiveness of vaccinating adults. The impact of this protection is inversely related to the level of natural immunity. Our results indicate that adult vaccination strategies should potentially be reassessed, and that it is important to include the protection of non-naive women previously infected with HPV in future studies. Furthermore, they also highlight the need for a more thorough investigation of this protection.

Abnormalities in the male reproductive system after exposure to diesel and biodiesel blend.

PubMed

Kisin, Elena R; Yanamala, Naveena; Farcas, Mariana T; Gutkin, Dmitriy W; Shurin, Michael R; Kagan, Valerian E; Bugarski, Aleksandar D; Shvedova, Anna A

2015-03-01

Altering the fuel source from petroleum-based ultralow sulfur diesel to biodiesel and its blends is considered by many to be a sustainable choice for controlling exposures to particulate material. As the exhaust of biodiesel/diesel blends is composed of a combination of combustion products of polycyclic aromatic hydrocarbons and fatty acid methyl esters, we hypothesize that 50% biodiesel/diesel blend (BD50) exposure could induce harmful outcomes because of its ability to trigger oxidative damage. Here, adverse effects were compared in murine male reproductive organs after pharyngeal aspiration with particles generated by engine fueled with BD50 or neat petroleum diesel (D100). When compared with D100, exposure to BD50 significantly altered sperm integrity, including concentration, motility, and morphological abnormalities, as well as increasing testosterone levels in testes during the time course postexposure. Serum level of luteinizing hormone was significantly depleted only after BD50 exposure. Moreover, we observed that exposure to BD50 significantly increased sperm DNA fragmentation and the upregulation of inflammatory cytokines in the serum and testes on Day 7 postexposure when compared with D100. Histological evaluation of testes sections from BD50 exposure indicated more noticeable interstitial edema, degenerating spermatocytes, and dystrophic seminiferous tubules with arrested spermatogenesis. Significant differences in the level of oxidative stress assessed by accumulation of lipid peroxidation products and depletion of glutathione were detected on exposure to respirable BD50 and D100. Taken together, these results indicate that exposure of mice to inhalable BD50 caused more pronounced adverse effects on male reproductive function than diesel. © 2014 Wiley Periodicals, Inc.

Abnormalities in the Male Reproductive System After Exposure to Diesel and Biodiesel Blend

PubMed Central

Kisin, Elena R.; Yanamala, Naveena; Farcas, Mariana T.; Gutkin, Dmitriy W.; Shurin, Michael R.; Kagan, Valerian E.; Bugarski, Aleksandar D.; Shvedova, Anna A.

2016-01-01

Altering the fuel source from petroleum-based ultra-low sulfur diesel to biodiesel and its blends is considered by many to be a sustainable choice for controlling exposures to particulate material. As the exhaust of biodiesel/diesel blends is composed of a combination of combustion products of polycyclic aromatic hydrocarbons and fatty acid methyl esters, we hypothesize that 50% biodiesel/diesel blend (BD50) exposure could induce harmful outcomes because of its ability to trigger oxidative damage. Here, adverse effects were compared in murine male reproductive organs after pharyngeal aspiration with particles generated by engine fueled with BD50 or neat petroleum diesel (D100). When compared with D100, exposure to BD50 significantly altered sperm integrity, including concentration, motility, and morphological abnormalities, as well as increasing testosterone levels in testes during the time course postexposure. Serum level of luteinizing hormone was significantly depleted only after BD50 exposure. Moreover, we observed that exposure to BD50 significantly increased sperm DNA fragmentation and the upregulation of inflammatory cytokines in the serum and testes on Day 7 postexposure when compared with D100. Histological evaluation of testes sections from BD50 exposure indicated more noticeable interstitial edema, degenerating spermatocytes, and dystrophic seminiferous tubules with arrested spermatogenesis. Significant differences in the level of oxidative stress assessed by accumulation of lipid peroxidation products and depletion of glutathione were detected on exposure to respirable BD50 and D100. Taken together, these results indicate that exposure of mice to inhalable BD50 caused more pronounced adverse effects on male reproductive function than diesel. PMID:25327512

Company-level, semi-quantitative assessment of occupational styrene exposure when individual data are not available.

PubMed

Kolstad, Henrik A; Sønderskov, Jette; Burstyn, Igor

2005-03-01

In epidemiological research, self-reported information about determinants and levels of occupational exposures is difficult to obtain, especially if the disease under study has a high mortality rate or follow-up has exceeded several years. In this paper, we present a semi-quantitative exposure assessment strategy for nested case-control studies of styrene exposure among workers of the Danish reinforced plastics industry when no information on job title, task or other indicators of individual exposure were readily available from cases and controls. The strategy takes advantage of the variability in styrene exposure level and styrene exposure probability across companies. The study comprised 1522 cases of selected malignancies and neurodegenerative diseases and controls employed in 230 reinforced plastics companies and other related industries. Between 1960 and 1996, 3057 measurements of styrene exposure level obtained from 191 companies, were identified. Mixed effects models were used to estimate expected styrene exposure levels by production characteristics for all companies. Styrene exposure probability within each company was estimated for all but three cases and controls from the fraction of laminators, which was reported by a sample of 945 living colleagues of the cases and controls and by employers and dealers of plastic raw materials. The estimates were validated from a subset of 427 living cases and controls that reported their own work as laminators in the industry. We computed styrene exposure scores that integrated estimated styrene exposure level and styrene exposure probability. Product (boats), process (hand and spray lamination) and calendar year period were the major determinants of styrene exposure level. Within-company styrene exposure variability increased by calendar year and was accounted for when computing the styrene exposure scores. Exposure probability estimates based on colleagues' reports showed the highest predictive values in the validation test, which also indicated that up to 67% of the workers were correctly classified into a styrene-exposed job. Styrene exposure scores declined about 10-fold from the 1960s-1990s. This exposure assessment approach may be justified in other industries, and especially in industries dominated by small companies with simple exposure conditions.

Parental Occupational Exposure to Heavy Metals and Welding Fumes and Risk of Testicular Germ Cell Tumors in Offspring: A Registry-Based Case-Control Study.

PubMed

Togawa, Kayo; Le Cornet, Charlotte; Feychting, Maria; Tynes, Tore; Pukkala, Eero; Hansen, Johnni; Olsson, Ann; Oksbjerg Dalton, Susanne; Nordby, Karl-Christian; Uuksulainen, Sanni; Wiebert, Pernilla; Woldbæk, Torill; Skakkebæk, Niels E; Fervers, Béatrice; Schüz, Joachim

2016-10-01

Data are scarce on the association between prenatal/preconception environmental exposure and testicular germ cell tumor (TGCT) in offspring. We examined parental occupational exposures to heavy metals and welding fumes in relation to TGCT in offspring in a registry-based case-control study (NORD-TEST Study). We identified TGCT cases diagnosed at ages 14-49 years in Finland (1988-2012), Norway (1978-2010), and Sweden (1979-2011) through nationwide cancer registries. These cases were individually matched by country and year of birth to controls selected from population registries. Information on parental occupations was retrieved from censuses. From this, we estimated prenatal/preconception exposures of chromium, iron, nickel, lead, and welding fumes (all three countries), and cadmium (Finland only) for each parent using job-exposure matrices specifying prevalence (P) and mean exposure level (L). Exposure indices were calculated as a product of P and L (P × L), and exposure categories were based on P × L or different combinations of P and L. The study comprised 8,112 cases and 26,264 controls. We observed no statistically significant TGCT risk associated with presence of heavy metals/welding fumes (P × L > 0) and no dose-response relationship (P trend ≥ 0.32). A statistically significant elevated TGCT risk was found in paternal exposure category where both P and L of chromium were high (vs. no chromium; OR = 1.37, 95% confidence interval; 1.05-1.79). Our study provides little evidence of associations between parental exposures to heavy metals/welding fumes and TGCT in offspring with the potential exception of high paternal chromium exposure. Further research on paternal chromium exposure is warranted. Cancer Epidemiol Biomarkers Prev; 25(10); 1426-34. ©2016 AACR. ©2016 American Association for Cancer Research.

Clinically defined non-specific symptoms in the vicinity of mobile phone base stations: A retrospective before-after study.

PubMed

Baliatsas, Christos; van Kamp, Irene; Bolte, John; Kelfkens, Gert; van Dijk, Christel; Spreeuwenberg, Peter; Hooiveld, Mariette; Lebret, Erik; Yzermans, Joris

2016-09-15

The number of mobile phone base station(s) (MPBS) has been increasing to meet the rapid technological changes and growing needs for mobile communication. The primary objective of the present study was to test possible changes in prevalence and number of NSS in relation to MPBS exposure before and after increase of installed MPBS antennas. A retrospective cohort study was conducted, comparing two time periods with high contrast in terms of number of installed MPBS. Symptom data were based on electronic health records from 1069 adult participants, registered in 9 general practices in different regions in the Netherlands. All participants were living within 500m from the nearest bases station. Among them, 55 participants reported to be sensitive to MPBS at T1. A propagation model combined with a questionnaire was used to assess indoor exposure to RF-EMF from MPBS at T1. Estimation of exposure at T0 was based on number of antennas at T0 relative to T1. At T1, there was a >30% increase in the total number of MPBS antennas. A higher prevalence for most NSS was observed in the MPBS-sensitive group at T1 compared to baseline. Exposure estimates were not associated with GP-registered NSS in the total sample. Some significant interactions were observed between MPBS-sensitivity and exposure estimates on risk of symptoms. Using clinically defined outcomes and a time difference of >6years it was demonstrated that RF-EMF exposure to MPBS was not associated with the development of NSS. Nonetheless, there was some indication for a higher risk of NSS for the MPBS-sensitive group, mainly in relation to exposure to UMTS, but this should be interpreted with caution. Results have to be verified by future longitudinal studies with a particular focus on potentially susceptible population subgroups of large sample size and integrated exposure assessment. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterizing multi-pollutant air pollution in China: Comparison of three air quality indices.

PubMed

Hu, Jianlin; Ying, Qi; Wang, Yungang; Zhang, Hongliang

2015-11-01

Multi-pollutant air pollution (i.e., several pollutants reaching very high concentrations simultaneously) frequently occurs in many regions across China. Air quality index (AQI) is used worldwide to inform the public about levels of air pollution and associated health risks. The current AQI approach used in China is based on the maximum value of individual pollutants, and does not consider the combined health effects of exposure to multiple pollutants. In this study, two novel alternative indices--aggregate air quality index (AAQI) and health-risk based air quality index (HAQI)--were calculated based on data collected in six megacities of China (Beijing, Shanghai, Guangzhou, Shjiazhuang, Xi'an, and Wuhan) during 2013 to 2014. Both AAQI and HAQI take into account the combined health effects of various pollutants, and the HAQI considers the exposure (or concentration)-response relationships of pollutants. AAQI and HAQI were compared to AQI to examine the effectiveness of the current AQI in characterizing multi-pollutant air pollution in China. The AAQI and HAQI values are higher than the AQI on days when two or more pollutants simultaneously exceed the Chinese Ambient Air Quality Standards (CAAQS) 24-hour Grade II standards. The results of the comparison of the classification of risk categories based on the three indices indicate that the current AQI approach underestimates the severity of health risk associated with exposure to multi-pollutant air pollution. For the AQI-based risk category of 'unhealthy', 96% and 80% of the days would be 'very unhealthy' or 'hazardous' if based on AAQI and HAQI, respectively; and for the AQI-based risk category of 'very unhealthy', 67% and 75% of the days would be 'hazardous' if based on AAQI and HAQI, respectively. The results suggest that the general public, especially sensitive population groups such as children and the elderly, should take more stringent actions than those currently suggested based on the AQI approach during high air pollution events. Sensitivity studies were conducted to examine the assumptions used in the AAQI and HAQI approaches. Results show that AAQI is sensitive to the choice of pollutant irrelevant constant. HAQI is sensitive to the choice of both threshold values and pollutants included in total risk calculation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Post—September 11, 2001, Incidence of Systemic Autoimmune Diseases in World Trade Center—Exposed Firefighters and Emergency Medical Service Workers

PubMed Central

Webber, Mayris P.; Moir, William; Crowson, Cynthia S.; Cohen, Hillel W.; Zeig-Owens, Rachel; Hall, Charles B.; Berman, Jessica; Qayyum, Basit; Jaber, Nadia; Matteson, Eric L.; Liu, Yang; Kelly, Kerry; Prezant, David J.

2016-01-01

Objective To estimate the incidence of selected systemic autoimmune diseases (SAIDs) in approximately 14,000 male rescue/recovery workers enrolled in the Fire Department of the City of New York (FDNY) World Trade Center (WTC) Health Program and to compare FDNY incidence to rates from demographically similar men in the Rochester Epidemiology Project (REP), a population-based database in Olmsted County, Minnesota. Patients and Methods We calculated incidence for specific SAIDs (rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and others) and combined SAIDs diagnosed from September 12, 2001, through September 11, 2014, and generated expected sex- and age-specific rates based on REP rates. Rates were stratified by level of WTC exposure (higher vs lower). Standardized incidence ratios (SIRs), which are the ratios of the observed number of cases in the FDNY group to the expected number of cases based on REP rates, and 95% CIs were calculated. Results We identified 97 SAID cases. Overall, FDNY rates were not significantly different from expected rates (SIR, 0.97; 95% CI, 0.77–1.21). However, the lower WTC exposure group had 9.9 fewer cases than expected, whereas the higher WTC exposure group had 7.7 excess cases. Conclusion Most studies indicate that the healthy worker effect reduces the association between exposure and outcome by about 20%, which we observed in the lower WTC exposure group. Overall rates masked differences in incidence by level of WTC exposure, especially because the higher WTC exposure group was relatively small. Continued surveillance for early detection of SAIDs in high WTC exposure populations is required to identify and treat exposure-related adverse effects. PMID:26682920

Post-September 11, 2001, Incidence of Systemic Autoimmune Diseases in World Trade Center-Exposed Firefighters and Emergency Medical Service Workers.

PubMed

Webber, Mayris P; Moir, William; Crowson, Cynthia S; Cohen, Hillel W; Zeig-Owens, Rachel; Hall, Charles B; Berman, Jessica; Qayyum, Basit; Jaber, Nadia; Matteson, Eric L; Liu, Yang; Kelly, Kerry; Prezant, David J

2016-01-01

To estimate the incidence of selected systemic autoimmune diseases (SAIDs) in approximately 14,000 male rescue/recovery workers enrolled in the Fire Department of the City of New York (FDNY) World Trade Center (WTC) Health Program and to compare FDNY incidence to rates from demographically similar men in the Rochester Epidemiology Project (REP), a population-based database in Olmsted County, Minnesota. We calculated incidence for specific SAIDs (rheumatoid arthritis, psoriatic arthritis, systemic lupus erythematosus, and others) and combined SAIDs diagnosed from September 12, 2001, through September 11, 2014, and generated expected sex- and age-specific rates based on REP rates. Rates were stratified by level of WTC exposure (higher vs lower). Standardized incidence ratios (SIRs), which are the ratios of the observed number of cases in the FDNY group to the expected number of cases based on REP rates, and 95% CIs were calculated. We identified 97 SAID cases. Overall, FDNY rates were not significantly different from expected rates (SIR, 0.97; 95% CI, 0.77-1.21). However, the lower WTC exposure group had 9.9 fewer cases than expected, whereas the higher WTC exposure group had 7.7 excess cases. Most studies indicate that the healthy worker effect reduces the association between exposure and outcome by about 20%, which we observed in the lower WTC exposure group. Overall rates masked differences in incidence by level of WTC exposure, especially because the higher WTC exposure group was relatively small. Continued surveillance for early detection of SAIDs in high WTC exposure populations is required to identify and treat exposure-related adverse effects. Copyright © 2016. Published by Elsevier Inc.

Environmental Tobacco Smoke and Adult-Onset Asthma: A Population-Based Incident Case–Control Study

PubMed Central

Jaakkola, Maritta S.; Piipari, Ritva; Jaakkola, Niina; Jaakkola, Jouni J. K.

2003-01-01

Objectives. The authors assessed the effects of environmental tobacco smoke (ETS) on the development of asthma in adults. Methods. In the Pirkanmaa district of South Finland, all 21- to 63-year-old adults with new cases of asthma diagnosed during a 2.5-year period (n = 521 case patients, out of 441 000 inhabitants) and a random sample of control subjects from the source population (932 control subjects) participated in a population-based incident case–control study. Results. Risk of asthma was related to workplace ETS exposure (adjusted odds ratio [OR] = 2.16; 95% confidence interval [CI] = 1.26, 3.72) and home exposure (OR = 4.77; 95% CI = 1.29, 17.7) in the past year. Cumulative ETS exposure over a lifetime at work and at home increased the risk. Conclusions. This study indicates for the first time that both cumulative lifetime and recent ETS exposures increase the risk of adult-onset asthma. PMID:14652334

Trait and State Craving as Indicators of Validity of VR-based Software for Binge Eating Treatment.

PubMed

Pla-Sanjuanelo, Joana; Ferrer-Garcia, Marta; Gutiérrez-Maldonado, José; Vilalta-Abella, Ferran; Andreu-Gracia, Alexis; Dakanalis, Antonios; Fernandez-Aranda, Fernando; Fusté-Escolano, Adela; Ribas-Sabaté, Joan; Riva, Giuseppe; Saldaña, Carmina; Sánchez, Isabel

2015-01-01

The aim of this study was to establish whether virtual reality (VR) exposure to food cues is able to produce craving levels consistent with state-craving and trait-craving as assessed by the Spanish and Italian versions of the State and Trait Food Craving Questionnaires (FCQ-T/S). The results were compared in 40 patients with eating disorders (17 with binge eating disorder, 23 with bulimia nervosa) and 78 healthy control subjects without eating disorders. Controls and patients with higher levels of trait-craving and state-craving both showed a greater desire to eat during VR exposure. Results also showed that trait and state craving assessed by FCQ-T/S were able to predict the total mean craving experienced during exposure to the VR software in both clinical and control samples. These findings present preliminary evidence about the validity of a new virtual reality-based application for cue-exposure treatment in patients with eating disorders.

A New Stress-Based Model of Political Extremism: Personal Exposure to Terrorism, Psychological Distress, and Exclusionist Political Attitudes.

PubMed

Canetti-Nisim, Daphna; Halperin, Eran; Sharvit, Keren; Hobfoll, Stevan E

2009-06-01

Does exposure to terrorism lead to hostility toward minorities? Drawing on theories from clinical and social psychology, we propose a stress-based model of political extremism in which psychological distress-which is largely overlooked in political scholarship-and threat perceptions mediate the relationship between exposure to terrorism and attitudes toward minorities. To test the model, a representative sample of 469 Israeli Jewish respondents was interviewed on three occasions at six-month intervals. Structural Equation Modeling indicated that exposure to terrorism predicted psychological distress (t1), which predicted perceived threat from Palestinian citizens of Israel (t2), which, in turn, predicted exclusionist attitudes toward Palestinian citizens of Israel (t3). These findings provide solid evidence and a mechanism for the hypothesis that terrorism introduces nondemocratic attitudes threatening minority rights. It suggests that psychological distress plays an important role in political decision making and should be incorporated in models drawing upon political psychology.

Spatial and Temporal Dynamics in Air Pollution Exposure Assessment

PubMed Central

Dias, Daniela; Tchepel, Oxana

2018-01-01

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

Toward a multi-country monitoring system of reproductive health in the context of endocrine disrupting chemical exposure.

PubMed

Le Moal, Joëlle; Sharpe, Richard M; Jϕrgensen, Niels; Levine, Hagai; Jurewicz, Joanna; Mendiola, Jaime; Swan, Shanna H; Virtanen, Helena; Christin-Maître, Sophie; Cordier, Sylvaine; Toppari, Jorma; Hanke, Wojciech

2016-02-01

Worrying trends regarding human reproductive endpoints (e.g. semen quality, reproductive cancers) have been reported and there is growing circumstantial evidence for a possible causal link between these trends and exposure to endocrine disrupting chemicals (EDCs). However, there is a striking lack of human data to fill the current knowledge gaps. To answer the crucial questions raised on human reproductive health, there is an urgent need for a reproductive surveillance system to be shared across countries. A multidisciplinary network named HUman Reproductive health and Global ENvironment Network (HURGENT) was created aiming at designing a European monitoring system for reproductive health indicators. Collaborative work allowed setting up the available knowledge to design such a system. Furthermore we conducted an overview of 23 potential indicators, based upon a weight of evidence (WoE) approach according to their potential relation with EDC exposure. The framework and purposes of the surveillance system are settled as well as the approach to select suitable reproductive indicators. The indicators found with the highest scores according to the WoE approach are prostate and breast cancer incidence, sex ratio, endometriosis and uterine fibroid incidence, indicators related to the testicular dysgenesis syndrome, precocious puberty incidence and reproductive hormone levels. Not only sentinel health endpoints, but also diseases with high burdens in public health are highlighted as prior indicators in the context of EDC exposure. Our work can serve as a basis to construct, as soon as possible, the first multi-country reproductive monitoring system. © The Author 2015. Published by Oxford University Press on behalf of the European Public Health Association. All rights reserved.

Identifying potential exposure reduction priorities using regional rankings based on emissions of known and suspected carcinogens to outdoor air in Canada.

PubMed

Setton, Eleanor M; Veerman, Basil; Erickson, Anders; Deschenes, Steeve; Cheasley, Roz; Poplawski, Karla; Demers, Paul A; Keller, C Peter

2015-08-22

Emissions inventories aid in understanding the sources of hazardous air pollutants and how these vary regionally, supporting targeted reduction actions. Integrating information on the relative toxicity of emitted pollutants with respect to cancer in humans helps to further refine reduction actions or recommendations, but few national programs exist in North America that use emissions estimates in this way. The CAREX Canada Emissions Mapping Project provides key regional indicators of emissions (total annual and total annual toxic equivalent, circa 2011) of 21 selected known and suspected carcinogens. The indicators were calculated from industrial emissions reported to the National Pollutant Release Inventory (NPRI) and estimates of emissions from transportation (airports, trains, and car and truck traffic) and residential heating (oil, gas and wood), in conjunction with human toxicity potential factors. We also include substance-specific annual emissions in toxic equivalent kilograms and annual emissions in kilograms, to allow for ranking substances within any region. For provinces and territories in Canada, the indicators suggest the top five substances contributing to the total toxic equivalent emissions in any region could be prioritized for further investigation. Residents of Quebec and New Brunswick may be more at risk of exposure to industrial emissions than those in other regions, suggesting that a more detailed study of exposure to industrial emissions in these provinces is warranted. Residential wood smoke may be an important emission to control, particularly in the north and eastern regions of Canada. Residential oil and gas heating, along with rail emissions contribute little to regional emissions and therefore may not be an immediate regional priority. The developed indicators support the identification of pollutants and sources for additional investigation when planning exposure reduction actions among Canadian provinces and territories, but have important limitations similar to other emissions inventory-based tools. Additional research is required to evaluate how the Emissions Mapping Project is used by different groups and organizations with respect to informing actions aimed at reducing Canadians' potential exposure to harmful air pollutants.

Using Hierarchical Cluster Models to Systematically Identify Groups of Jobs With Similar Occupational Questionnaire Response Patterns to Assist Rule-Based Expert Exposure Assessment in Population-Based Studies

PubMed Central

Friesen, Melissa C.; Shortreed, Susan M.; Wheeler, David C.; Burstyn, Igor; Vermeulen, Roel; Pronk, Anjoeka; Colt, Joanne S.; Baris, Dalsu; Karagas, Margaret R.; Schwenn, Molly; Johnson, Alison; Armenti, Karla R.; Silverman, Debra T.; Yu, Kai

2015-01-01

Objectives: Rule-based expert exposure assessment based on questionnaire response patterns in population-based studies improves the transparency of the decisions. The number of unique response patterns, however, can be nearly equal to the number of jobs. An expert may reduce the number of patterns that need assessment using expert opinion, but each expert may identify different patterns of responses that identify an exposure scenario. Here, hierarchical clustering methods are proposed as a systematic data reduction step to reproducibly identify similar questionnaire response patterns prior to obtaining expert estimates. As a proof-of-concept, we used hierarchical clustering methods to identify groups of jobs (clusters) with similar responses to diesel exhaust-related questions and then evaluated whether the jobs within a cluster had similar (previously assessed) estimates of occupational diesel exhaust exposure. Methods: Using the New England Bladder Cancer Study as a case study, we applied hierarchical cluster models to the diesel-related variables extracted from the occupational history and job- and industry-specific questionnaires (modules). Cluster models were separately developed for two subsets: (i) 5395 jobs with ≥1 variable extracted from the occupational history indicating a potential diesel exposure scenario, but without a module with diesel-related questions; and (ii) 5929 jobs with both occupational history and module responses to diesel-relevant questions. For each subset, we varied the numbers of clusters extracted from the cluster tree developed for each model from 100 to 1000 groups of jobs. Using previously made estimates of the probability (ordinal), intensity (µg m−3 respirable elemental carbon), and frequency (hours per week) of occupational exposure to diesel exhaust, we examined the similarity of the exposure estimates for jobs within the same cluster in two ways. First, the clusters’ homogeneity (defined as >75% with the same estimate) was examined compared to a dichotomized probability estimate (<5 versus ≥5%; <50 versus ≥50%). Second, for the ordinal probability metric and continuous intensity and frequency metrics, we calculated the intraclass correlation coefficients (ICCs) between each job’s estimate and the mean estimate for all jobs within the cluster. Results: Within-cluster homogeneity increased when more clusters were used. For example, ≥80% of the clusters were homogeneous when 500 clusters were used. Similarly, ICCs were generally above 0.7 when ≥200 clusters were used, indicating minimal within-cluster variability. The most within-cluster variability was observed for the frequency metric (ICCs from 0.4 to 0.8). We estimated that using an expert to assign exposure at the cluster-level assignment and then to review each job in non-homogeneous clusters would require ~2000 decisions per expert, in contrast to evaluating 4255 unique questionnaire patterns or 14983 individual jobs. Conclusions: This proof-of-concept shows that using cluster models as a data reduction step to identify jobs with similar response patterns prior to obtaining expert ratings has the potential to aid rule-based assessment by systematically reducing the number of exposure decisions needed. While promising, additional research is needed to quantify the actual reduction in exposure decisions and the resulting homogeneity of exposure estimates within clusters for an exposure assessment effort that obtains cluster-level expert assessments as part of the assessment process. PMID:25477475

Using hierarchical cluster models to systematically identify groups of jobs with similar occupational questionnaire response patterns to assist rule-based expert exposure assessment in population-based studies.

PubMed

Friesen, Melissa C; Shortreed, Susan M; Wheeler, David C; Burstyn, Igor; Vermeulen, Roel; Pronk, Anjoeka; Colt, Joanne S; Baris, Dalsu; Karagas, Margaret R; Schwenn, Molly; Johnson, Alison; Armenti, Karla R; Silverman, Debra T; Yu, Kai

2015-05-01

Rule-based expert exposure assessment based on questionnaire response patterns in population-based studies improves the transparency of the decisions. The number of unique response patterns, however, can be nearly equal to the number of jobs. An expert may reduce the number of patterns that need assessment using expert opinion, but each expert may identify different patterns of responses that identify an exposure scenario. Here, hierarchical clustering methods are proposed as a systematic data reduction step to reproducibly identify similar questionnaire response patterns prior to obtaining expert estimates. As a proof-of-concept, we used hierarchical clustering methods to identify groups of jobs (clusters) with similar responses to diesel exhaust-related questions and then evaluated whether the jobs within a cluster had similar (previously assessed) estimates of occupational diesel exhaust exposure. Using the New England Bladder Cancer Study as a case study, we applied hierarchical cluster models to the diesel-related variables extracted from the occupational history and job- and industry-specific questionnaires (modules). Cluster models were separately developed for two subsets: (i) 5395 jobs with ≥1 variable extracted from the occupational history indicating a potential diesel exposure scenario, but without a module with diesel-related questions; and (ii) 5929 jobs with both occupational history and module responses to diesel-relevant questions. For each subset, we varied the numbers of clusters extracted from the cluster tree developed for each model from 100 to 1000 groups of jobs. Using previously made estimates of the probability (ordinal), intensity (µg m(-3) respirable elemental carbon), and frequency (hours per week) of occupational exposure to diesel exhaust, we examined the similarity of the exposure estimates for jobs within the same cluster in two ways. First, the clusters' homogeneity (defined as >75% with the same estimate) was examined compared to a dichotomized probability estimate (<5 versus ≥5%; <50 versus ≥50%). Second, for the ordinal probability metric and continuous intensity and frequency metrics, we calculated the intraclass correlation coefficients (ICCs) between each job's estimate and the mean estimate for all jobs within the cluster. Within-cluster homogeneity increased when more clusters were used. For example, ≥80% of the clusters were homogeneous when 500 clusters were used. Similarly, ICCs were generally above 0.7 when ≥200 clusters were used, indicating minimal within-cluster variability. The most within-cluster variability was observed for the frequency metric (ICCs from 0.4 to 0.8). We estimated that using an expert to assign exposure at the cluster-level assignment and then to review each job in non-homogeneous clusters would require ~2000 decisions per expert, in contrast to evaluating 4255 unique questionnaire patterns or 14983 individual jobs. This proof-of-concept shows that using cluster models as a data reduction step to identify jobs with similar response patterns prior to obtaining expert ratings has the potential to aid rule-based assessment by systematically reducing the number of exposure decisions needed. While promising, additional research is needed to quantify the actual reduction in exposure decisions and the resulting homogeneity of exposure estimates within clusters for an exposure assessment effort that obtains cluster-level expert assessments as part of the assessment process. Published by Oxford University Press on behalf of the British Occupational Hygiene Society 2014.

Current implications of past DDT indoor spraying in Oman.

PubMed

Booij, Petra; Holoubek, Ivan; Klánová, Jana; Kohoutek, Jiří; Dvorská, Alice; Magulová, Katarína; Al-Zadjali, Said; Čupr, Pavel

2016-04-15

In Oman, DDT was sprayed indoors during an intensive malaria eradication program between 1976 and 1992. DDT can remain for years after spraying and is associated with potential health risk. This raises the concern for human exposure in areas where DDT was used for indoor spraying. Twelve houses in three regions with a different history of DDT indoor spraying were chosen for a sampling campaign in 2005 to determine p,p'-dichlorodiphenyltrichloroethane (p,p'-DDT), p,p'-dichlorodiphenyldichloroethylene (p,p'-DDE) and p,p'-dichlorodiphenyldichloroethane (p,p'-DDD) levels in indoor air, dust, and outdoor soil. Although DDT was only sprayed indoor, p,p'-DDT, p,p'-DDE and p,p'-DDD were also found in outdoor soil. The results indicate that release and exposure continue for years after cessation of spraying. The predicted cancer risk based on concentrations determined in 2005, indicate that there was still a significant cancer risk up to 13 to 16years after indoor DDT spraying. A novel approach, based on region-specific half-lives, was used to predict concentrations in 2015 and showed that more than 21years after spraying, cancer risk for exposure to indoor air, dust, and outdoor soil are acceptable in Oman for adults and young children. The model can be used for other locations and countries to predict prospective exposure of contaminants based on indoor experimental measurements and knowledge about the spraying time-schedule to extrapolate region-specific half-lives and predict effects on the human population years after spraying. Copyright © 2015 Elsevier B.V. All rights reserved.

Fluoride exposure and indicators of thyroid functioning in the Canadian population: implications for community water fluoridation.

PubMed

Barberio, Amanda M; Hosein, F Shaun; Quiñonez, Carlos; McLaren, Lindsay

2017-10-01

There are concerns that altered thyroid functioning could be the result of ingesting too much fluoride. Community water fluoridation (CWF) is an important source of fluoride exposure. Our objectives were to examine the association between fluoride exposure and (1) diagnosis of a thyroid condition and (2) indicators of thyroid functioning among a national population-based sample of Canadians. We analysed data from Cycles 2 and 3 of the Canadian Health Measures Survey (CHMS). Logistic regression was used to assess associations between fluoride from urine and tap water samples and the diagnosis of a thyroid condition. Multinomial logistic regression was used to examine the relationship between fluoride exposure and thyroid-stimulating hormone (TSH) level (low/normal/high). Other available variables permitted additional exploratory analyses among the subset of participants for whom we could discern some fluoride exposure from drinking water and/or dental products. There was no evidence of a relationship between fluoride exposure (from urine and tap water) and the diagnosis of a thyroid condition. There was no statistically significant association between fluoride exposure and abnormal (low or high) TSH levels relative to normal TSH levels. Rerunning the models with the sample constrained to the subset of participants for whom we could discern some source(s) of fluoride exposure from drinking water and/or dental products revealed no significant associations. These analyses suggest that, at the population level, fluoride exposure is not associated with impaired thyroid functioning in a time and place where multiple sources of fluoride exposure, including CWF, exist. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Health survey of former workers in a Norwegian coke plant: Part. 1. Estimation of historical exposures

PubMed Central

Romundstad, P. R.; Ronneberg, A.; Leira, H. L.; Bye, T.

1998-01-01

OBJECTIVE: To estimate historical exposure levels at a coke plant for all agents considered to be of importance for epidemiological studies of mortality and cancer incidence. METHODS: Time weighted average exposure (8 h TWA) was estimated based on personal measurements for polycyclic aromatic hydrocarbons (PAHs) and carbonaceous particulates. Exposure to quartz was estimated relative to the concentration of carbonaceous particulates. These estimates were adjusted for the use of airstream helmets. Exposure to other agents were estimated qualitatively (asbestos, benzene, and arsenic) or semi-quantitatively (carbon monoxide (CO) and heat) based on measurements and other indicators of exposure. RESULTS: Exposure to PAHs was highest for those who worked at the top of the ovens (300 micrograms/m3) in the period from 1970-6. The estimated PAH exposure was reduced to an average of 65 micrograms/m3 after the introduction of exposure control measures in 1976. The estimates for carbonaceous particulates ranged from 1 to 16 mg/m3, with the highest exposure for workers at the top of the ovens and at the coke screening station. CONCLUSIONS: The exposure of greatest concern in this study is to PAHs, but exposures to carbonaceous particulates and CO may also be of importance. The major limitations of this study are the lack of personal measurements before 1975 and the total lack of measurements for some of the exposed categories of workers. Despite these limitations, we think that this assessment reflects the actual exposures for most of the former employees. The assessment thus provides a reasonable tool for the subsequent epidemiological study and for future epidemiological follow up studies at the coke plant.   PMID:9861184

Radio-frequency electromagnetic field (RF-EMF) exposure levels in different European outdoor urban environments in comparison with regulatory limits.

PubMed

Urbinello, Damiano; Joseph, Wout; Huss, Anke; Verloock, Leen; Beekhuizen, Johan; Vermeulen, Roel; Martens, Luc; Röösli, Martin

2014-07-01

Concerns of the general public about potential adverse health effects caused by radio-frequency electromagnetic fields (RF-EMFs) led authorities to introduce precautionary exposure limits, which vary considerably between regions. It may be speculated that precautionary limits affect the base station network in a manner that mean population exposure unintentionally increases. The objectives of this multicentre study were to compare mean exposure levels in outdoor areas across four different European cities and to compare with regulatory RF-EMF exposure levels in the corresponding areas. We performed measurements in the cities of Amsterdam (the Netherlands, regulatory limits for mobile phone base station frequency bands: 41-61 V/m), Basel (Switzerland, 4-6 V/m), Ghent (Belgium, 3-4.5 V/m) and Brussels (Belgium, 2.9-4.3 V/m) using a portable measurement device. Measurements were conducted in three different types of outdoor areas (central and non-central residential areas and downtown), between 2011 and 2012 at 12 different days. On each day, measurements were taken every 4s for approximately 15 to 30 min per area. Measurements per urban environment were repeated 12 times during 1 year. Arithmetic mean values for mobile phone base station exposure ranged between 0.22 V/m (Basel) and 0.41 V/m (Amsterdam) in all outdoor areas combined. The 95th percentile for total RF-EMF exposure varied between 0.46 V/m (Basel) and 0.82 V/m (Amsterdam) and the 99th percentile between 0.81 V/m (Basel) and 1.20 V/m (Brussels). All exposure levels were far below international reference levels proposed by ICNIRP (International Commission on Non-Ionizing Radiation Protection). Our study did not find indications that lowering the regulatory limit results in higher mobile phone base station exposure levels. Copyright © 2014 Elsevier Ltd. All rights reserved.

Does short-term exposure to mobile phone base station signals increase symptoms in individuals who report sensitivity to electromagnetic fields? A double-blind randomized provocation study.

PubMed

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-11-01

Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself.

Does Short-Term Exposure to Mobile Phone Base Station Signals Increase Symptoms in Individuals Who Report Sensitivity to Electromagnetic Fields? A Double-Blind Randomized Provocation Study

PubMed Central

Eltiti, Stacy; Wallace, Denise; Ridgewell, Anna; Zougkou, Konstantina; Russo, Riccardo; Sepulveda, Francisco; Mirshekar-Syahkal, Dariush; Rasor, Paul; Deeble, Roger; Fox, Elaine

2007-01-01

Background Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) believe they suffer negative health effects when exposed to electromagnetic fields from everyday objects such as mobile phone base stations. Objectives This study used both open provocation and double-blind tests to determine if sensitive and control individuals experience more negative health effects when exposed to base station-like signals compared with sham. Methods Fifty-six self-reported sensitive and 120 control participants were tested in an open provocation test. Of these, 12 sensitive and 6 controls withdrew after the first session. The remainder completed a series of double-blind tests. Subjective measures of well-being and symptoms as well as physiological measures of blood volume pulse, heart rate, and skin conductance were obtained. Results During the open provocation, sensitive individuals reported lower levels of well-being in both the global system for mobile communication (GSM) and universal mobile telecommunications system (UMTS) compared with sham exposure, whereas controls reported more symptoms during the UMTS exposure. During double-blind tests the GSM signal did not have any effect on either group. Sensitive participants did report elevated levels of arousal during the UMTS condition, whereas the number or severity of symptoms experienced did not increase. Physiological measures did not differ across the three exposure conditions for either group. Conclusions Short-term exposure to a typical GSM base station-like signal did not affect well-being or physiological functions in sensitive or control individuals. Sensitive individuals reported elevated levels of arousal when exposed to a UMTS signal. Further analysis, however, indicated that this difference was likely to be due to the effect of order of exposure rather than the exposure itself. PMID:18007992

Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line

USGS Publications Warehouse

Kienzler, Aude; Mahler, Barbara J.; Van Metre, Peter C.; Schweigert, Nathalie; Devaux, Alain; Bony, Sylvie

2015-01-01

Coal-tar-based (CTB) sealcoat, frequently applied to parking lots and driveways in North America, contains elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and related compounds. The RTL-W1 fish liver cell line was used to investigate two endpoints (genotoxicity and DNA-repair-capacity impairment) associated with exposure to runoff from asphalt pavement with CTB sealcoat or with an asphalt-based sealcoat hypothesized to contain about 7% CTB sealcoat (AS-blend). Genotoxic potential was assessed by the Formamido pyrimidine glycosylase (Fpg)-modified comet assay for 1:10 and 1:100 dilutions of runoff samples collected from 5 h to 36 d following sealcoat application. DNA-repair capacity was assessed by the base excision repair comet assay for 1:10 dilution of samples collected 26 h and 36 d following application. Both assays were run with and without co-exposure to ultraviolet-A radiation (UVA). With co-exposure to UVA, genotoxic effects were significant for both dilutions of CTB runoff for three of four sample times, and for some samples of AS-blend runoff. Base excision repair was significantly impaired for CTB runoff both with and without UVA exposure, and for AS-blend runoff only in the absence of UVA. This study is the first to investigate the effects of exposure to the complex mixture of chemicals in coal tar on DNA repair capacity. The results indicate that co-exposure to runoff from CT-sealcoated pavement and UVA as much as a month after sealcoat application has the potential to cause genotoxicity and impair DNA repair capacity.

Exposure to runoff from coal-tar-sealed pavement induces genotoxicity and impairment of DNA repair capacity in the RTL-W1 fish liver cell line.

PubMed

Kienzler, Aude; Mahler, Barbara J; Van Metre, Peter C; Schweigert, Nathalie; Devaux, Alain; Bony, Sylvie

2015-07-01

Coal-tar-based (CTB) sealcoat, frequently applied to parking lots and driveways in North America, contains elevated concentrations of polycyclic aromatic hydrocarbons (PAHs) and related compounds. The RTL-W1 fish liver cell line was used to investigate two endpoints (genotoxicity and DNA-repair-capacity impairment) associated with exposure to runoff from asphalt pavement with CTB sealcoat or with an asphalt-based sealcoat hypothesized to contain about 7% CTB sealcoat (AS-blend). Genotoxic potential was assessed by the Formamido pyrimidine glycosylase (Fpg)-modified comet assay for 1:10 and 1:100 dilutions of runoff samples collected from 5 h to 36 d following sealcoat application. DNA-repair capacity was assessed by the base excision repair comet assay for 1:10 dilution of samples collected 26 h and 36 d following application. Both assays were run with and without co-exposure to ultraviolet-A radiation (UVA). With co-exposure to UVA, genotoxic effects were significant for both dilutions of CTB runoff for three of four sample times, and for some samples of AS-blend runoff. Base excision repair was significantly impaired for CTB runoff both with and without UVA exposure, and for AS-blend runoff only in the absence of UVA. This study is the first to investigate the effects of exposure to the complex mixture of chemicals in coal tar on DNA repair capacity. The results indicate that co-exposure to runoff from CT-sealcoated pavement and UVA as much as a month after sealcoat application has the potential to cause genotoxicity and impair DNA repair capacity. Copyright © 2015 Elsevier B.V. All rights reserved.

Assessment of the mutagenic potential of ethanol auto engine exhaust gases by the Salmonella typhimurium microsomal mutagenesis assay, using a direct exposure method.

PubMed

Lotfi, C F; Brentani, M M; Böhm, G M

1990-08-01

The mutagenic activity of the new Brazilian fuel, ethanol, was determined by employing the Salmonella typhimurium microsomal mutagenesis assay (TA97, TA98, TA100, TA102, and TA104) and a direct exposure method. This methodology was first used to determine the mutagenic activity of gasoline, revealing mutagenic activity of base-pair substitution without any need for metabolic activation, indicating the presence of direct-action mutagens. Experiments with ethanol suggest an indirect mutagenic activity of the oxidant type. The exposure system was considered suitable for future studies of gaseous mixtures.

Assessing the impact of race, social factors and air pollution on birth outcomes: a population-based study.

PubMed

Gray, Simone C; Edwards, Sharon E; Schultz, Bradley D; Miranda, Marie Lynn

2014-01-29

Both air pollution exposure and socioeconomic status (SES) are important indicators of children's health. Using highly resolved modeled predictive surfaces, we examine the joint effects of air pollution exposure and measures of SES in a population level analysis of pregnancy outcomes in North Carolina (NC). Daily measurements of particulate matter <2.5 μm in aerodynamic diameter (PM2.5) and ozone (O3) were calculated through a spatial hierarchical Bayesian model which produces census-tract level point predictions. Using multilevel models and NC birth data from 2002-2006, we examine the association between pregnancy averaged PM2.5 and O3, individual and area-based SES indicators, and birth outcomes. Maternal race and education, and neighborhood household income were associated with adverse birth outcomes. Predicted concentrations of PM2.5 and O3 were also associated with an additional effect on reductions in birth weight and increased risks of being born low birth weight and small for gestational age. This paper builds on and complements previous work on the relationship between pregnancy outcomes and air pollution exposure by using 1) highly resolved air pollution exposure data; 2) a five-year population level sample of pregnancies; and 3) including personal and areal level measures of social determinants of pregnancy outcomes. Results show a stable and negative association between air pollution exposure and adverse birth outcomes. Additionally, the more socially disadvantaged populations are at a greater risk; controlling for both SES and environmental stressors provides a better understanding of the contributing factors to poor children's health outcomes.

Mapping environmental injustices: pitfalls and potential of geographic information systems in assessing environmental health and equity.

PubMed Central

Maantay, Juliana

2002-01-01

Geographic Information Systems (GIS) have been used increasingly to map instances of environmental injustice, the disproportionate exposure of certain populations to environmental hazards. Some of the technical and analytic difficulties of mapping environmental injustice are outlined in this article, along with suggestions for using GIS to better assess and predict environmental health and equity. I examine 13 GIS-based environmental equity studies conducted within the past decade and use a study of noxious land use locations in the Bronx, New York, to illustrate and evaluate the differences in two common methods of determining exposure extent and the characteristics of proximate populations. Unresolved issues in mapping environmental equity and health include lack of comprehensive hazards databases; the inadequacy of current exposure indices; the need to develop realistic methodologies for determining the geographic extent of exposure and the characteristics of the affected populations; and the paucity and insufficiency of health assessment data. GIS have great potential to help us understand the spatial relationship between pollution and health. Refinements in exposure indices; the use of dispersion modeling and advanced proximity analysis; the application of neighborhood-scale analysis; and the consideration of other factors such as zoning and planning policies will enable more conclusive findings. The environmental equity studies reviewed in this article found a disproportionate environmental burden based on race and/or income. It is critical now to demonstrate correspondence between environmental burdens and adverse health impacts--to show the disproportionate effects of pollution rather than just the disproportionate distribution of pollution sources. PMID:11929725

Prenatal exposure to an environmentally relevant phthalate mixture disrupts reproduction in F1 female mice

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhou, Changqing; Gao, Liying; Flaws, Jodi A., E-ma

Phthalates are used in a large variety of products, such as building materials, medical devices, and personal care products. Most previous studies on the toxicity of phthalates have focused on single phthalates, but it is also important to study the effects of phthalate mixtures because humans are exposed to phthalate mixtures. Thus, we tested the hypothesis that prenatal exposure to an environmentally relevant phthalate mixture adversely affects female reproduction in mice. To test this hypothesis, pregnant CD-1 dams were orally dosed with vehicle (tocopherol-stripped corn oil) or a phthalate mixture (20 and 200 μg/kg/day, 200 and 500 mg/kg/day) daily frommore » gestational day 10 to birth. The mixture was based on the composition of phthalates detected in urine samples from pregnant women in Illinois. The mixture included 35% diethyl phthalate, 21% di(2-ethylhexyl) phthalate, 15% dibutyl phthalate, 15% diisononyl phthalate, 8% diisobutyl phthalate, and 5% benzylbutyl phthalate. Female mice born to the exposed dams were subjected to tissue collections and fertility tests at different ages. Our results indicate that prenatal exposure to the phthalate mixture significantly increased uterine weight and decreased anogenital distance on postnatal days 8 and 60, induced cystic ovaries at 13 months, disrupted estrous cyclicity, reduced fertility-related indices, and caused some breeding complications at 3, 6, and 9 months of age. Collectively, our data suggest that prenatal exposure to an environmentally relevant phthalate mixture disrupts aspects of female reproduction in mice. - Highlights: • Prenatal exposure to a phthalate mixture disrupts F1 estrous cyclicity. • Prenatal exposure to a phthalate mixture induces F1 ovarian cysts. • Prenatal exposure to a phthalate mixture decreases F1 female fertility-related indices. • Prenatal exposure to a phthalate mixture induces F1 breeding complications.« less

On the use of different measures of exposure-experiences from a case-control study on testicular cancer and PVC exposure.

PubMed

Westberg, Håkan B T; Hardell, Lennart O; Malmqvist, Nils; Ohlson, Carl-Göran; Axelson, Olav

2005-07-01

Associations between exposure to PVC plastics and testicular cancer have been reported. To improve the exposure-response analysis in a matched case-control study on testicular cancer and occupational exposures, a self-administered exposure questionnaire and expert assessment was applied and different exposure measures were developed. The questionnaires regarding work histories and employment in PVC production, manufacturing, and handling of PVC products were completed by 1582 subjects (90%). By expert assessment, 360 subjects were considered exposed, and the exposure intensity to PVC plastics for different working periods was determined. Different exposure measures to PVC plastics were then developed, such as ever/never exposed, duration, maximum intensity, median intensity, and cumulative median intensity. The correlation between the different measures of exposure was high for exposure duration and the cumulative median exposure intensity (Spearman rank coefficient r(s) = 0.94), as was the correlation between the maximum intensity and the median intensity (r(s) = 0.94). The agreement between the answers in the questionnaire and the expert assessments was moderate, Kappa value 0.56. The odds ratio for "ever" exposed based on the exposure as reported in the questionnaire was 1.1 (95%, CI 0.82-1.56), and as determined by expert assessment 1.3 (CI 1.05-1.69). The odds ratios for all four different categories of exposure measures varied between 0.86 and 2.6 but decreased by increasing exposure. An overall excess of testicular cancer for the PVC exposed vs. the unexposed was not supported by the pattern seen in a standard exposure-response analysis based on several exposure measures. The findings stress the importance of using several exposure measures as dose surrogates when the underlying toxic mechanisms are unknown and when there are indications of an overall effect.

2013 update on sea otter studies to assess recovery from the 1989 Exxon Valdez oil spill, Prince William Sound, Alaska

USGS Publications Warehouse

Ballachey, Brenda E.; Monson, Daniel H.; Esslinger, George G.; Kloecker, Kimberly A.; Bodkin, James L.; Bowen, Lizabeth; Miles, A. Keith

2014-01-01

On March 24, 1989, the tanker vessel Exxon Valdez ran aground in Prince William Sound, Alaska, spilling an estimated 42 million liters of Prudhoe Bay crude oil. Oil spread in a southwesterly direction and was deposited on shores and waters in western Prince William Sound (WPWS). The sea otter (Enhydra lutris) was one of more than 20 nearshore species considered to have been injured by the spill. Since 1989, the U.S. Geological Survey has led a research program to evaluate effects of the spill on sea otters and assess progress toward recovery, as defined by demographic and biochemical indicators. Here, we provide an update on the status of sea otter populations in WPWS, presenting findings through 2013. To assess recovery based on demographic indicators, we used aerial surveys to estimate abundance and annual collections of sea otter carcasses to evaluate patterns in ages-at-death. To assess recovery based on biochemical indicators, we quantified transcription rates for a suite of genes selected as potential indicators of oil exposure in sea otters based on laboratory studies of a related species, the mink (Mustela vison). In our most recent assessment of sea otter recovery, which incorporated results from a subset of studies through 2009, we concluded that recovery of sea otters in WPWS was underway. This conclusion was based on increasing abundance throughout WPWS, including increasing numbers at northern Knight Island, an area that was heavily oiled in 1989 and where the local sea otter population had previously shown protracted injury and lack of recovery. However, we did not conclude that the WPWS sea otter population had fully recovered, due to indications of continuing reduced survival and exposure to lingering oil in sea otters at Knight Island, at least through 2009. Based on data available through 2013, we now conclude that the status of sea otters—at all spatial scales within WPWS—is consistent with the designation of recovery from the spill as defined by the Exxon Valdez Oil Spill Trustee Council. The support for this conclusion is based primarily on demographic data, including (1) a return to estimated pre-spill abundance of sea otters at northern Knight Island, and (2) a return to pre-spill mortality patterns. Gene transcription rates in 2012 were similar in sea otters from oiled, moderately oiled and unoiled areas, suggesting abatement of exposure effects in 2012. However, because 2012 gene transcription rates generally were low for sea otters from all areas relative to 2008, we cannot fully interpret these observations without data from a wider panel of genes. This slight uncertainty with respect to the data from the biochemical indicator is outweighed by the strength of the data for the demographic indicators. The return to pre-spill numbers and mortality patterns suggests a gradual dissipation of lingering oil over the past two decades, to the point where continuing exposure is no longer of biological significance to the WPWS sea otter population.

Inorganic Arsenic and Basal Cell Carcinoma in Areas of Hungary, Romania, and Slovakia: A Case–Control Study

PubMed Central

Leonardi, Giovanni; Vahter, Marie; Clemens, Felicity; Goessler, Walter; Gurzau, Eugen; Hemminki, Kari; Hough, Rupert; Koppova, Kvetoslava; Kumar, Rajiv; Rudnai, Peter; Surdu, Simona

2012-01-01

Background: Inorganic arsenic (iAs) is a potent carcinogen, but there is a lack of information about cancer risk for concentrations < 100 μg/L in drinking water. Objectives: We aimed to quantify skin cancer relative risks in relation to iAs exposure < 100 μg/L and the modifying effects of iAs metabolism. Methods: The Arsenic Health Risk Assessment and Molecular Epidemiology (ASHRAM) study, a case–control study, was conducted in areas of Hungary, Romania, and Slovakia with reported presence of iAs in groundwater. Consecutively diagnosed cases of basal cell carcinoma (BCC) of the skin were histologically confirmed; controls were general surgery, orthopedic, and trauma patients who were frequency matched to cases by age, sex, and area of residence. Exposure indices were constructed based on information on iAs intake over the lifetime of participants. iAs metabolism status was classified based on urinary concentrations of methylarsonic acid (MA) and dimethylarsinic acid (DMA). Associations were estimated by multivariable logistic regression. Results: A total of 529 cases with BCC and 540 controls were recruited for the study. BCC was positively associated with three indices of iAs exposure: peak daily iAs dose rate, cumulative iAs dose, and lifetime average water iAs concentration. The adjusted odds ratio per 10-μg/L increase in average lifetime water iAs concentration was 1.18 (95% confidence interval: 1.08, 1.28). The estimated effect of iAs on cancer was stronger in participants with urinary markers indicating incomplete metabolism of iAs: higher percentage of MA in urine or a lower percentage of DMA. Conclusion: We found a positive association between BCC and exposure to iAs through drinking water with concentrations < 100 μg/L. PMID:22436128

The International Agency for Research on Cancer (IARC) evaluation of the carcinogenicity of outdoor air pollution: focus on China.

PubMed

Loomis, Dana; Huang, Wei; Chen, Guosheng

2014-04-01

The International Agency for Research on Cancer (IARC) has classified outdoor air pollution and the particulate matter (PM) in outdoor air pollution as carcinogenic to humans, as based on sufficient evidence of carcinogenicity in humans and experimental animals and strong support by mechanistic studies. The data with important contributions to the evaluation are reviewed, highlighting the data with particular relevance to China, and implications of the evaluation with respect to China are discussed. The air pollution levels in Chinese cities are among the highest observed in the world today and frequently exceed health-based national and international guidelines. Data from high-quality epidemiologic studies in Asia, Europe, and North America consistently show positive associations between lung cancer and PM exposure and other indicators of air pollution, which persist after adjustment for important lung cancer risk factors, such as tobacco smoking. Epidemiologic data from China are limited but nevertheless indicate an increased risk of lung cancer associated with several air pollutants. Excess cancer risk is also observed in experimental animals exposed to polluted outdoor air or extracted PM. The exposure of several species to outdoor air pollution is associated with markers of genetic damage that have been linked to increased cancer risk in humans. Numerous studies from China, especially genetic biomarker studies in exposed populations, support that the polluted air in China is genotoxic and carcinogenic to humans. The evaluation by IARC indicates both the need for further research into the cancer risks associated with exposure to air pollution in China and the urgent need to act to reduce exposure to the population.

The International Agency for Research on Cancer (IARC) evaluation of the carcinogenicity of outdoor air pollution: focus on China

PubMed Central

Loomis, Dana; Huang, Wei; Chen, Guosheng

2014-01-01

The International Agency for Research on Cancer (IARC) has classified outdoor air pollution and the particulate matter (PM) in outdoor air pollution as carcinogenic to humans, as based on sufficient evidence of carcinogenicity in humans and experimental animals and strong support by mechanistic studies. The data with important contributions to the evaluation are reviewed, highlighting the data with particular relevance to China, and implications of the evaluation with respect to China are discussed. The air pollution levels in Chinese cities are among the highest observed in the world today and frequently exceed health-based national and international guidelines. Data from high-quality epidemiologic studies in Asia, Europe, and North America consistently show positive associations between lung cancer and PM exposure and other indicators of air pollution, which persist after adjustment for important lung cancer risk factors, such as tobacco smoking. Epidemiologic data from China are limited but nevertheless indicate an increased risk of lung cancer associated with several air pollutants. Excess cancer risk is also observed in experimental animals exposed to polluted outdoor air or extracted PM. The exposure of several species to outdoor air pollution is associated with markers of genetic damage that have been linked to increased cancer risk in humans. Numerous studies from China, especially genetic biomarker studies in exposed populations, support that the polluted air in China is genotoxic and carcinogenic to humans. The evaluation by IARC indicates both the need for further research into the cancer risks associated with exposure to air pollution in China and the urgent need to act to reduce exposure to the population. PMID:24694836

Extent of exposure to environmental tobacco smoke (ETS) and its dose-response relation to respiratory health among adults

PubMed Central

Maziak, Wasim; Ward, Kenneth D; Rastam, Samer; Mzayek, Fawaz; Eissenberg, Thomas

2005-01-01

Background There is a dearth of standardized studies examining exposure to environmental tobacco smoke (ETS) and its relationship to respiratory health among adults in developing countries. Methods In 2004, the Syrian Center for Tobacco Studies (SCTS) conducted a population-based survey using stratified cluster sampling to look at issues related to environmental health of adults aged 18–65 years in Aleppo (2,500,000 inhabitants). Exposure to ETS was assessed from multiple self-reported indices combined into a composite score (maximum 22), while outcomes included both self-report (symptoms/diagnosis of asthma, bronchitis, and hay fever), and objective indices (spirometric assessment of FEV1 and FVC). Logistic and linear regression analyses were conducted to study the relation between ETS score and studied outcomes, whereby categorical (tertiles) and continuous scores were used respectively, to evaluate the association between ETS exposure and respiratory health, and explore the dose-response relationship of the association. Results Of 2038 participants, 1118 were current non-smokers with breath CO levels ≤ 10 ppm (27.1% men, mean age 34.7 years) and were included in the current analysis. The vast majority of study participants were exposed to ETS, whereby only 3.6% had ETS score levels ≤ 2. In general, there was a significant dose-response pattern in the relationship of ETS score with symptoms of asthma, hay fever, and bronchitis, but not with diagnoses of these outcomes. The magnitude of the effect was in the range of twofold increases in the frequency of symptoms reported in the high exposure group compared to the low exposure group. Severity of specific respiratory problems, as indicated by frequency of symptoms and health care utilization for respiratory problems, was not associated with ETS exposure. Exposure to ETS was associated with impaired lung function, indicative of airflow limitation, among women only. Conclusions This study provides evidence for the alarming extent of exposure to ETS among adult non-smokers in Syria, and its dose-response relationship with respiratory symptoms of infectious and non-infectious nature. It calls for concerted efforts to increase awareness of this public health problem and to enforce regulations aimed at protecting non-smokers. PMID:15701169

Indoor air quality in hospitality venues before and after implementation of a clean indoor air law--Western New York, 2003.

PubMed

2004-11-12

Secondhand smoke (SHS) contains more than 50 carcinogens. SHS exposure is responsible for an estimated 3,000 lung cancer deaths and more than 35,000 coronary heart disease deaths among never smokers in the United States each year, and for lower respiratory infections, asthma, sudden infant death syndrome, and chronic ear infections among children. Even short-term exposures to SHS, such as those that might be experienced by a patron in a restaurant or bar that allows smoking, can increase the risk of experiencing an acute cardiovascular event. Although population-based data indicate declining SHS exposure in the United States over time, SHS exposure remains a common but preventable public health hazard. Policies requiring smoke-free environments are the most effective method of reducing SHS exposure. Effective July 24, 2003, New York implemented a comprehensive state law requiring almost all indoor workplaces and public places (e.g., restaurants, bars, and other hospitality venues) to be smoke-free. This report describes an assessment of changes in indoor air quality that occurred in 20 hospitality venues in western New York where smoking or indirect SHS exposure from an adjoining room was observed at baseline. The findings indicate that, on average, levels of respirable suspended particles (RSPs), an accepted marker for SHS levels, decreased 84% in these venues after the law took effect. Comprehensive clean indoor air policies can rapidly and effectively reduce SHS exposure in hospitality venues.

The effects of low environmental cadmium exposure on bone density

DOE Office of Scientific and Technical Information (OSTI.GOV)

Trzcinka-Ochocka, M., E-mail: ochocka@imp.lodz.pl; Jakubowski, M.; Szymczak, W.

2010-04-15

Recent epidemiological data indicate that low environmental exposure to cadmium, as shown by cadmium body burden (Cd-U), is associated with renal dysfunction as well as an increased risk of cadmium-induced bone disorders. The present study was designed to assess the effects of low environmental cadmium exposure, at the level sufficient to induce kidney damage, on bone metabolism and mineral density (BMD). The project was conducted in the area contaminated with cadmium, nearby a zinc smelter located in the region of Poland where heavy industry prevails. The study population comprised 170 women (mean age=39.7; 18-70 years) and 100 men (mean age=31.9;more » 18-76 years). Urinary and blood cadmium and the markers of renal tubular dysfunction ({beta}{sub 2}M-U RBP, NAG), glomerular dysfunction (Alb-U and {beta}{sub 2}M-S) and bone metabolism markers (BAP-S, CTX-S) as well as forearm BMD, were measured. The results of this study based on simple dose-effect analysis showed the relationship between increasing cadmium concentrations and an increased excretion of renal dysfunction markers and decreasing bone density. However, the results of the multivariate analysis did not indicate the association between exposure to cadmium and decrease in bone density. They showed that the most important factors that have impact on bone density are body weight and age in the female subjects and body weight and calcium excretion in males. Our investigation revealed that the excretion of low molecular weight proteins occurred at a lower level of cadmium exposure than the possible loss of bone mass. It seems that renal tubular markers are the most sensitive and significant indicators of early health effects of cadmium intoxication in the general population. The correlation of urinary cadmium concentration with markers of kidney dysfunction was observed in the absence of significant correlations with bone effects. Our findings did not indicate any effects of environmental cadmium exposure on bone density.« less

Occupational Exposure to Nano-Objects and Their Agglomerates and Aggregates Across Various Life Cycle Stages; A Broad-Scale Exposure Study.

PubMed

Bekker, Cindy; Kuijpers, Eelco; Brouwer, Derk H; Vermeulen, Roel; Fransman, Wouter

2015-07-01

Occupational exposure to manufactured nano-objects and their agglomerates, and aggregates (NOAA) has been described in several workplace air monitoring studies. However, data pooling for general conclusions and exposure estimates are hampered by limited exposure data across the occupational life cycle of NOAA and a lack in comparability between the methods of collecting and analysing the data. By applying a consistent method of collecting and analysing the workplace exposure data, this study aimed to provide information about the occupational NOAA exposure levels across various life cycle stages of NOAA in the Netherlands which can also be used for multi-purpose use. Personal/near field task-based exposure data was collected using a multi-source exposure assessment method collecting real time particle number concentration, particle size distribution (PSD), filter-based samples for morphological, and elemental analysis and detailed contextual information. A decision logic was followed allowing a consistent and objective way of analysing the exposure data. In total, 46 measurement surveys were conducted at 15 companies covering 18 different exposure situations across various occupational life cycle stages of NOAA. Highest activity-effect levels were found during replacement of big bags (<1000-76000 # cm(-3)), mixing/dumping of powders manually (<1000-52000 # cm(-3)) and mechanically (<1000-100000 # cm(-3)), and spraying of liquid (2000-800000 # cm(-3)) showing a high variability between and within the various exposure situations. In general, a limited change in PSD was found during the activity compared to the background. This broad-scale exposure study gives a comprehensive overview of the NOAA exposure situations in the Netherlands and an indication of the levels of occupational exposure to NOAA across various life cycle of NOAA. The collected workplace exposure data and contextual information will serve as basis for future pooling of data and modelling of worker exposure. © The Author 2015. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Gene transcription patterns in response to low level petroleum contaminants in Mytilus trossulus from field sites and harbors in southcentral Alaska

USGS Publications Warehouse

Bowen, Lizabeth; Miles, A. Keith; Ballachey, Brenda E.; Waters, Shannon C.; Bodkin, James L.; Lindeberg, Mandy; Esler, Daniel N.

2017-01-01

The 1989 Exxon Valdez oil spill damaged a wide range of natural resources, including intertidal communities, and post-spill studies demonstrated acute and chronic exposure and injury to an array of species. Standard toxicological methods to evaluate petroleum contaminants have assessed tissue burdens, with fewer assays providing indicators of health or physiology, particularly when contaminant levels are low and chronic. Marine mussels are a ubiquitous and crucial component of the nearshore environment, and new genomic technologies exist to quantify molecular responses of individual mussels to stimuli, including exposure to polycyclic aromatic hydrocarbons (PAHs). We used gene-based assays of exposure and physiological function to assess chronic oil contamination using the Pacific blue mussel, Mytilus trossulus. We developed a diagnostic gene transcription panel to investigate exposure to PAHs and other contaminants and its effects on mussel physiology and health. During 2012–2015, we analyzed mussels from five field sites in western Prince William Sound, Alaska, with varying oil histories from the 1989 Exxon Valdez oil spill, and from three boat harbors in the area. Gene transcription patterns of mussels from harbors were consistent with elevated exposure to PAHs or other contaminants, whereas transcription patterns of mussels sampled from shorelines in areas affected by the oil spill indicated no PAH exposure.

Lead in ammunition: a persistent threat to health and conservation.

PubMed

Johnson, C K; Kelly, T R; Rideout, B A

2013-12-01

Many scavenging bird populations have experienced abrupt declines across the globe, and intensive recovery activities have been necessary to sustain several species, including the critically endangered California condor (Gymnogyps californianus). Exposure to lead from lead-based ammunition is widespread in condors and lead toxicosis presents an immediate threat to condor recovery, accounting for the highest proportion of adult mortality. Lead contamination of carcasses across the landscape remains a serious threat to the health and sustainability of scavenging birds, and here we summarize recent evidence for exposure to lead-based ammunition and health implications across many species. California condors and other scavenging species are sensitive indicators of the occurrence of lead contaminated carcasses in the environment. Transdisciplinary science-based approaches have been critical to managing lead exposure in California condors and paving the way for use of non-lead ammunition in California. Similar transdisciplinary approaches are now needed to translate the science informing on this issue and establish education and outreach efforts that focus on concerns brought forth by key stakeholders.

Setting Occupational Exposure Limits for Genotoxic Substances in the Pharmaceutical Industry.

PubMed

Lovsin Barle, Ester; Winkler, Gian Christian; Glowienke, Susanne; Elhajouji, Azeddine; Nunic, Jana; Martus, Hans-Joerg

2016-05-01

In the pharmaceutical industry, genotoxic drug substances are developed for life-threatening indications such as cancer. Healthy employees handle these substances during research, development, and manufacturing; therefore, safe handling of genotoxic substances is essential. When an adequate preclinical dataset is available, a risk-based decision related to exposure controls for manufacturing is made following a determination of safe health-based limits, such as an occupational exposure limit (OEL). OELs are calculated for substances based on a threshold dose-response once a threshold is identified. In this review, we present examples of genotoxic mechanisms where thresholds can be demonstrated and OELs can be calculated, including a holistic toxicity assessment. We also propose a novel approach for inhalation Threshold of Toxicological Concern (TTC) limit for genotoxic substances in cases where the database is not adequate to determine a threshold. © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Evaluation of exposure-response relationships for health effects of microbial bioaerosols - A systematic review.

PubMed

Walser, Sandra M; Gerstner, Doris G; Brenner, Bernhard; Bünger, Jürgen; Eikmann, Thomas; Janssen, Barbara; Kolb, Stefanie; Kolk, Annette; Nowak, Dennis; Raulf, Monika; Sagunski, Helmut; Sedlmaier, Nadja; Suchenwirth, Roland; Wiesmüller, Gerhard; Wollin, Klaus-Michael; Tesseraux, Irene; Herr, Caroline E W

2015-10-01

Studies suggest adverse health effects following exposure to bioaerosols in the environment and in particular at workplaces. However, there is still a lack of health-related exposure limits based on toxicological or epidemiological studies from environmental health or from the working environment. The aim of this study was to derive health-based exposure limits for bioaerosols that can protect the general population as group "at risk" via environmental exposure using analysis of peer-reviewed studies related to occupational medicine, indoor air and environmental health. The derivation of exposure limits should be conducted by the members of a bioaerosol expert panel according to established toxicological criteria. A systematic review was performed in Medline (PubMed) including studies containing both data on exposure measurements and observed health outcomes. In addition, literature recommended by the experts was considered. A comprehensive search strategy was generated and resulted in a total of n=1569 studies in combination with the literature recommendations. Subsequently, abstracts were screened using defined exclusion criteria yielding a final number of n=44 studies. A standardized extraction sheet was used to combine data on health effects and exposure to different bioaerosols. After full-text screening and extraction according to the defined exclusion criteria n=20 studies were selected all related to occupational exposures comprising the working areas wood processing, farming, waste processing and others. These studies were analyzed in collaboration with the bioaerosol expert network in terms of suitability for derivation of health-related exposure limits. The bioaerosol expert network concluded that none of the analyzed studies provided suitable dose-response relationships for derivation of exposure limits. The main reasons were: (1) lack of studies with valid dose-response data; (2) diversity of employed measuring methods for microorganisms and bioaerosol-emitting facilities; (3) heterogeneity of health effects; (4) insufficient exposure assessment. However, several indicator parameters and exposure concentrations could be identified for different bioaerosol-emitting facilities. Nevertheless, health-related exposure limits are urgently needed especially in approval procedures of facilities like composting plants or livestock farms emitting bioaerosols in the neighbourhood of residents. In the regulatory toxicology framework, it is common to use animal experimental studies for derivation of general exposure limits if appropriate environmental epidemiological studies on harmful substances are lacking. This might be another possibility to obtain health-related exposure limits for specific bioaerosol parameters. Furthermore, we recommend to use suitable measurable outcome parameters related to bioaerosols; to measure bioaerosols according to a protocol representative for exposure pattern and duration at the particular work place; to develop standardized detection methods for indicator parameters; to combine different detection methods to compensate for the limitations of each method; to apply new analysis methods to identify the real risk potential. Copyright © 2015 Elsevier GmbH. All rights reserved.

Hydrocarbon exposure may cause glomerulonephritis and worsen renal function: evidence based on Hill's criteria for causality.

PubMed

Ravnskov, U

2000-08-01

Many observational and experimental studies point to hydrocarbon exposure as an important pathogenic factor in glomerulonephritis. The findings have made little impact on current concepts and patient care, possibly because the hypothesis of a direct causal effect of the exposure and the hypothesis that the exposure worsens renal function have not been considered separately. This review examines these two hypotheses using Hill's criteria for causality. The results from 14 cross-sectional, 18 case-control studies, two cohort studies, 15 experiments on laboratory animals and two on human beings together with many case reports satisfy all but one of Hill's criteria for both hypotheses. Of particular importance is the finding in the case-control and follow-up studies of an association between degree of exposure and stage of renal disease, and an inverse association between degree of exposure and renal function, indicating that the most important effect of hydrocarbon exposure is its effect on renal function. End-stage renal failure may be preventable in many patients with glomerulonephritis provided a possible exposure to toxic chemicals is discontinued.

A case‐control study of airways obstruction among construction workers

PubMed Central

Welch, Laura; Ringen, Knut; Quinn, Patricia; Chen, Anna; Haas, Scott

2015-01-01

Background While smoking is the major cause of chronic obstructive pulmonary disease (COPD), occupational exposures to vapors, gases, dusts, and fumes (VGDF) increase COPD risk. This case‐control study estimated the risk of COPD attributable to occupational exposures among construction workers. Methods The study population included 834 cases and 1243 controls participating in a national medical screening program for older construction workers between 1997 and 2013. Qualitative exposure indices were developed based on lifetime work and exposure histories. Results Approximately 18% (95%CI = 2–24%) of COPD risk can be attributed to construction‐related exposures, which are additive to the risk contributed by smoking. A measure of all VGDF exposures combined was a strong predictor of COPD risk. Conclusions Construction workers are at increased risk of COPD as a result of broad and complex effects of many exposures acting independently or interactively. Control methods should be implemented to prevent worker exposures, and smoking cessation should be promoted. Am. J. Ind. Med. 58:1083–1097, 2015. © 2015 The Authors. American Journal of Industrial Medicine Published by Wiley Periodicals, Inc. PMID:26123003

Secondhand Smoke Exposure Levels in Outdoor Hospitality Venues: A Qualitative and Quantitative Review of the Research Literature

PubMed Central

LICHT, ANDREA S; HYLAND, ANDREW; TRAVERS, MARK J; CHAPMAN, SIMON

2013-01-01

Objective This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in high enough levels of hospitality venues to potentially pose health risks, particularly among employees of such establishments. Data Sources Search strings in PubMed and Web of Science included combinations of environmental tobacco smoke, secondhand smoke, or passive smoke AND outdoor, yielding 217 and 5,199 results, respectively through June, 2012. Study Selection Sixteen studies were selected based on abstract review that either entirely or partly measured outdoor SHS exposures (particulate matter (PM) or other SHS indicators). Data Extraction The methods used to measure SHS indicators, particularly PM, were assessed for inclusion of extraneous variables that may affect such measurements or the corroboration of ambient levels with known standards. Data Synthesis The magnitude of SHS exposure (PM2.5) is dependent on the number of smokers present, proximity to the measuring device, outdoor enclosures, and wind. Under specific conditions, peak outdoor PM2.5 levels can be comparable to those recorded in indoor smoky environments. Using data from both observational and experimental studies, annual excess PM2.5 exposure of full-time waitstaff at outdoor smoking environments could average 4.0 to 12.2 μg/m3 under variable smoking conditions. Conclusions Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. However, such exposures are likely to be higher for occupationally exposed individuals compared to patrons due to repeated and cumulative outdoor SHS exposures. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates. PMID:23220937

Estimating exposure to groundwater contaminants in karst areas

NASA Astrophysics Data System (ADS)

Butscher, C.

2012-12-01

Large multidisciplinary projects investigate health effects and environmental impacts of contamination. Such multidisciplinary projects challenge groundwater hydrologist because they demand estimations of human or environmental exposure to groundwater contaminants. But especially in karst regions, groundwater quality is subject to rapid changes resulting from highly dynamic flow systems with rapid groundwater recharge and contaminant transport in karst conduits. There is a strong need for tools that allow the quantification of the risk of contaminant exposure via the karst groundwater and its temporal variation depending on rainfall events and overall hydrological conditions. A fact that makes the assessment of contaminant exposure even more difficult is that many contaminants behave differently in the subsurface than the groundwater, because they do not dissolve and exist as a separate phase. Important examples are particulate contaminants, such as bacteria, and non-aqueous phase liquids (NAPLs), such as many organic compounds. Both are ubiquitous in the environment and have large potential for health impacts. It is known from bacterial contamination of karst springs that such contamination is strongly related to flow conditions. Bacteria, which are present at the land surface, in the soil, rock matrix or the conduit system, are immobile during base flow conditions. During storm events however, they become mobilized and are rapidly transported through the conduit flow system from sources to areas of potential exposure. As a result, bacteria concentrations that most times are low at a spring can show a high peak during storm flow. Conceptual models exist that suggest that the transport of NAPLs in karst aquifers is, just like bacterial contamination, related to flow conditions. Light NAPLs that reach the saturated zone float and accumulate on the water table; and dense NAPLs sink downward in the aquifer until they are trapped in pores, fractures and conduits where they remain stationary under base flow conditions. During storm flows, however, they can be dragged downstream or flushed as suspensions and emulsions. As a result, storm flow can send previously immobilized NAPLs to exposure zones in toxic pulses. An approach is presented to estimate the risk of contaminant exposure by bacteria and NAPLs via the groundwater under variable hydrological conditions (Butscher et al. 2011). The approach uses an indicator that is expressed as the Dynamic Vulnerability Index (DVI). This index is defined as the ratio of conduit to matrix flow contributions to spring discharge, and is calculated based on a numerical model simulating karst groundwater flow. The approach is illustrated at a test site in Switzerland, where calculated DVI was compared to the occurrence of fecal indicators during five storm flow events. Key words: karst hydrogeology; groundwater contamination; fecal indicators; NAPLs; numerical modeling References: Butscher, C. Auckenthaler, A., Scheidler, S., Huggenberger, P. (2011). Validation of a Numerical Indicator of Microbial Contamination for Karst Springs. Ground Water 49 (1), 66-76.

Why International?

ERIC Educational Resources Information Center

Falcetta, Frank M.

1993-01-01

Discusses the benefits of international programs at community colleges based on the example of Middlesex Community College in Bedford, Massachusetts. Indicates that international programs broaden the perspective of the campus, generate new revenue and positive media exposure, contribute to professional development of faculty and staff, and provide…

Occupational exposure to lead and lung cancer: results from two case-control studies in Montreal, Canada.

PubMed

Wynant, Willy; Siemiatycki, Jack; Parent, Marie-Élise; Rousseau, Marie-Claude

2013-03-01

We investigated the association between workplace lead exposure and lung cancer risk, separately for organic lead and for inorganic lead, from either engine emissions or from other sources. Two population-based case-control studies were carried out in Montreal (1979-1986 and 1996-2002) to investigate occupational factors in relation to lung cancer among 1593 men with histologically confirmed incident lung cancer, and 1426 controls from the general population. Interviews elicited information on sociodemographic characteristics, lifetime smoking and occupational history. Chemists translated each job into potential chemical exposures. Cumulative indices of exposure were derived and classified into non-substantial and substantial exposure. ORs adjusted for several potential confounders including smoking, and 95% CIs were estimated by logistic regression. Lifetime prevalences of exposure in Study I were 3% for organic lead, 40% for inorganic lead from engine emissions and 17% for inorganic lead from other sources; corresponding prevalences in Study II were 4%, 19% and 16%, respectively. No associations were observed when comparing ever to never exposed subjects in pooled analyses (organic lead, OR=1.39, 95% CI 0.77 to 2.52; inorganic lead from engine emissions: OR=0.89, 95% CI 0.72 to 1.09; inorganic lead from other sources: OR=0.99, 95% CI 0.76 to 1.29). Nor were these exposures associated with lung cancer in subjects with substantial cumulative exposure. In this large study, using a blinded expert-based assessment of lifetime occupational exposure and adjustment for several potential confounders, we observed no increased risk of lung cancer with exposure to lead compounds.

[Subjective sensations indicating simulator sickness and fatigue after exposure to virtual reality].

PubMed

Malińska, Marzena; Zuzewicz, Krystyna; Bugajska, Joanna; Grabowski, Andrzej

2014-01-01

The study assessed the incidence and intensity of subjective symptoms indicating simulator sickness among the persons with no inclination to motion sickness, immersed in virtual reality (VR) by watching an hour long movie in the stereoscopic (three-dimensional - 3D) and non-stereoscopic (two-dimensional - 2D) versions and after an hour long training using virtual reality, called sVR. The sample comprised 20 healthy young men with no inclination to motion sickness. The participants' subjective sensations, indicating symptoms of simulator sickness were assessed using the questionnaire completed by the participants immediately, 20 min and 24 h following the test. Grandjean's scale was used to assess fatigue and mood. The symptoms were observed immediately after the exposure to sVR. Their intensity was higher than after watching the 2D and 3D movies. A significant relationship was found between the eye pain and the type of exposure (2D, 3D and sVR) (Chi2)(2) = 6.225, p < or = 0.05); the relationship between excessive perspiration and the exposure to 31) movie and sVR was also noted (Chi2(1) = 9.173, p < or = 0.01). Some symptoms were still observed 20 min after exposure to sVR. The comparison of Grandjean's scale results before and after the training in sVR handing showed significant differences in 11 out of 14 subscales. Before and after exposure to 3D movie, the differences were significant only for the "tired-fatigued" subscale (Z = 2.501, p < or = 0.012) in favor of "fatigued". Based on the subjective sensation of discomfort after watching 2D and 3D movies it is impossible to predict symptoms of simulator sickness after training using sVR.

Risk Factors for Smoking in Rural Women: The Role of Gender-Based Sexual and Intimate Partner Violence.

PubMed

Nemeth, Julianna M; Bonomi, Amy E; Lu, Bo; Lomax, Richard G; Wewers, Mary Ellen

2016-12-01

Women living in Ohio Appalachia experience cervical cancer at disproportionately high rates. Intimate partner and sexual gender-based violence (GBV) and smoking are independent risk factors for cervical cancer and interact to heighten risk. Appalachian women smoke at higher rates than other Ohio women, but little is known about GBV exposure in the region. The purpose of this study was to establish prevalence of women's exposure to GBV in Ohio Appalachia and examine the association between GBV and smoking among women in the region. A two-phase address-based random sampling approach was used in three purposefully selected Ohio Appalachian counties to identify women to complete an interviewer administered cross-sectional survey (n = 398). The primary exposure variable was GBV Index Score, a 4 level indices representing increasing exposure to eight abuse types. Correlation analysis and logistic regression were used to examine smoking correlations and risk. Almost 57% of women in the three selected Ohio Appalachian counties experienced GBV, with rate increasing to 77.5% among current smokers. The distribution of the GBV Exposure Index Score was significantly different across smoking status (p < = 0.0001), with exposure of GBV increasing when moving from never, to former, to current smokers. When controlling for depression, age, and adult socioeconomic position, GBV Exposure Index was significantly associated with current smoking behavior (OR:1.62, 95% CI [1.21-2.17]). Professionals working to reduce disparate disease burden among women in Ohio Appalachia should consider the role GBV plays in health behavior and behavioral change interventions, including smoking and smoking cessation.

Porcine dermal lesions produced by 1540-nm laser radiation pulses

NASA Astrophysics Data System (ADS)

Roach, William P.; Johnson, Thomas E.

2001-07-01

Completion of recent studies within our group indicates a breed-based difference in dermal response to 1540 nm 0.8 millisecond laser pulses. Laser exposure to Yucatan Mini- Pigs (highly pigmented skin) and Yorkshire pigs (lightly pigmented skin) demonstrate statistical differences between the ED50's of the two breeds. Laser delivery is accomplished using an Er:Glass system producing 1540 nm of light at millisecond exposure times and in the range of 5 to 95 J/cm2. Dermal lesion development was evaluated for acute, 1 hour, and 24-hour post exposure presentation. Our data contradicts the theory that water absorption is the sole mechanism of dermal tissue damage observed from 1540 nm laser exposures, as skin chromophores appear to play a role in lesion development.

Human health risk assessment of lead pollution in atmospheric deposition in Baoshan District, Shanghai.

PubMed

Chen, Yuanyuan; Wang, Jun; Shi, Guitao; Sun, Xiaojing; Chen, Zhenlou; Xu, Shiyuan

2011-12-01

The lead (Pb) content in atmospheric deposition was determined at 42 sampling sites in Baoshan District of Shanghai, China. Based on exposure and dose-response assessments, the health risk caused by Pb exposure in atmospheric deposition was investigated. The results indicated that Pb was significantly accumulated in atmospheric deposition. The spatial distribution of Pb was mapped by geostatistical analysis, and the results showed that pollution hotspots were present at traffic and industrial zones. Ingestion was the main route of Pb exposure in both adults and children. For children the risk value was above 1, whereas it was below 1 for the adult group. Therefore, children belong to the high-risk group for Pb exposure from atmospheric deposition in the observed area of Shanghai, China.

Movie Smoking Exposure and Smoking Onset: A Longitudinal Study of Mediation Processes in a Representative Sample of U.S. Adolescents

PubMed Central

Wills, Thomas A.; Sargent, James D.; Stoolmiller, Mike; Gibbons, Frederick X.; Gerrard, Meg

2009-01-01

The authors tested 2 mechanisms for the relation of movie smoking exposure with onset of cigarette smoking in adolescence. Longitudinal data with 8-month follow-up were obtained from a representative sample of 6,522 U.S. adolescents, ages 10–14 years. Structural modeling analysis based on initial nonsmokers, which controlled for 10 covariates associated with movie exposure, showed that viewing more smoking in movies was related to increases in positive expectancies about smoking and increases in affiliation with smoking peers, and these variables were both related to smoking onset. A direct effect of movie exposure on smoking onset was also noted. Mediation findings were replicated across cross-sectional and longitudinal analyses. Tests for gender differences indicated that girls showed larger effects of movie exposure for some variables. Implications for policy and prevention research are discussed. PMID:18540724

Cumulative Exposure to Neighborhood Context: Consequences for Health Transitions over the Adult Life Course

PubMed Central

Clarke, Philippa; Morenoff, Jeffrey; Debbink, Michelle; Golberstein, Ezra; Elliott, Michael R.; Lantz, Paula M.

2012-01-01

Over the last two decades, research has assessed the relationship between neighborhood socioeconomic factors and individual health. However, existing research is based almost exclusively on cross-sectional data, ignoring the complexity in health transitions that may be shaped by long term residential exposures. We address these limitations by specifying distinct health transitions over multiple waves of a 15 year study of American adults. We focus on transitions between a hierarchy of health states, (free from health problems, onset of health problems, and death), not just gradients in a single health indicator over time, and use a cumulative measure of exposure to neighborhoods over adulthood. We find that cumulative exposure to neighborhood disadvantage has significant effects on functional decline and mortality. Research ignoring a persons’ history of exposure to residential contexts over the life course runs the risk of underestimating the role of neighborhood disadvantage on health. PMID:24465068

Exposure to Community Violence and Sexual Behaviors Among African American Youth: Testing Multiple Pathways.

PubMed

Voisin, Dexter R; Hotton, Anna; Neilands, Torsten

2018-01-01

African American youth bear a disproportionate burden of sexually transmitted infections. A growing number of studies document that youth exposure to community violence and sexual behaviors are highly correlated. Despite such growing evidence, only a few studies have empirically tested conceptually driven pathways that may account for such relationships. This study seeks to address that gap by exploring multiple pathways linking exposure to community violence and youth sexual behaviors. Using an existing sample of 563 African American youth attending high school, we examined whether possible links between exposure to community violence and sexual activity, sexual risk behaviors were mediated by aggression, low student-teacher connectedness, and negative peer norms. Major findings indicated indirect relationships between exposures to community violence and both sexual activity and risky sex, mediated by aggression and negative peer norms with no significant differences based on gender or socioeconomic status. Overall findings also indicated a significant indirect effect of aggression to risky sex via negative peer norms and from community violence to risky peer norms via aggression. By illuminating ways that community violence, aggression, peer norms, and sexual behaviors are dynamically interrelated, these findings have significant implications for future research and intervention initiatives aimed at addressing the different pathways.

NMR data (ppm) from liver cells exposed to surfactant-wrapped (SDS) and oxidized (-OH) multi-walled carbon nanotubes (MWCNTs)

EPA Pesticide Factsheets

Carbon nanotubes (CNTs) have great potential in industrial, consumer, and mechanical applications, based partly on their unique structural, optical and electronic properties. CNTs are commonly oxidized or treated with surfactants to facilitate aqueous solution processing, and these CNT surface modifications also increase possible human and ecological exposures to nanoparticle-contaminated waters. To determine the exposure outcomes of oxidized and surfactant-wrapped multiwalled carbon nanotubes (MWCNTs) on biochemical processes, metabolomics based profiling of human liver cells (C3A) was utilized. Cells were exposed to 0, 10, or 100 ng/mL of MWCNTs for 24 and 48 hr. MWCNT particle size distribution, charge, and aggregation were monitored concurrently during exposures. Following MWCNT exposure, cellular metabolites were extracted, lyophilized, and buffered for 1H NMR analysis. Acquired spectra were subjected to both multivariate and univariate analysis to determine the consequences of nanotube exposure on the metabolite profile of C3A cells. Resulting scores plots illustrated temporal and dose-dependent metabolite responses to all MWCNTs tested. Loadings plots coupled with t-test filtered spectra identified metabolites of interest. XPS analysis revealed the presence of hydroxyl and carboxyl functionalities on both MWCNTs surfaces. Metal content analysis by ICP-AES indicated that the total mass concentration of the potentially toxic impurities in the exposure exper

Cancer risk from incidental ingestion exposures to PAHs associated with coal-tar-sealed pavement

USGS Publications Warehouse

Williams, E. Spencer; Mahler, Barbara J.; Van Metre, Peter C.

2012-01-01

Recent (2009-10) studies documented significantly higher concentrations of polycyclic aromatic hydrocarbons (PAHs) in settled house dust in living spaces and soil adjacent to parking lots sealed with coal-tar-based products. To date, no studies have examined the potential human health effects of PAHs from these products in dust and soil. Here we present the results of an analysis of potential cancer risk associated with incidental ingestion exposures to PAHs in settings near coal-tar-sealed pavement. Exposures to benzo[a]pyrene equivalents were characterized across five scenarios. The central tendency estimate of excess cancer risk resulting from lifetime exposures to soil and dust from nondietary ingestion in these settings exceeded 1 × 10–4, as determined using deterministic and probabilistic methods. Soil was the primary driver of risk, but according to probabilistic calculations, reasonable maximum exposure to affected house dust in the first 6 years of life was sufficient to generate an estimated excess lifetime cancer risk of 6 × 10–5. Our results indicate that the presence of coal-tar-based pavement sealants is associated with significant increases in estimated excess lifetime cancer risk for nearby residents. Much of this calculated excess risk arises from exposures to PAHs in early childhood (i.e., 0–6 years of age).

Prenatal exposure to environmental contaminants and body composition at age 7–9 years

DOE Office of Scientific and Technical Information (OSTI.GOV)

Delvaux, Immle; Van Cauwenberghe, Jolijn; Den Hond, Elly

2014-07-15

The study aim was to investigate the association between prenatal exposure to endocrine disrupting chemicals (EDCs) and the body composition of 7 to 9 year old Flemish children. The subjects were 114 Flemish children (50% boys) that took part in the first Flemish Environment and Health Study (2002–2006). Cadmium, PCBs, dioxins, p,p′-DDE and HCB were analysed in cord blood/plasma. When the child reached 7–9 years, height, weight, waist circumference and skinfolds were measured. Significant associations between prenatal exposure to EDCs and indicators of body composition were only found in girls. After adjustment for confounders and covariates, a significant negative associationmore » was found in girls between prenatal cadmium exposure and weight, BMI and waist circumference (indicator of abdominal fat) and the sum of four skinfolds (indicator of subcutaneous fat). In contrast, a significant positive association (after adjustment for confounders/covariates) was found between prenatal p,p′-DDE exposure and waist circumference as well as waist/height ratio in girls (indicators of abdominal fat). No significant associations were found for prenatal PCBs, dioxins and HCB exposure after adjustment for confounders/covariates. This study suggests a positive association between prenatal p,p′-DDE exposure and indicators of abdominal fat and a negative association between prenatal cadmium exposure and indicators of both abdominal as well as subcutaneous fat in girls between 7 and 9 years old. - Highlights: • Associations between prenatal contaminant exposure and anthropometrics in children. • Significant association only found in girls. • No significant associations found for prenatal PCBs, dioxins and HCB exposure. • Girls: negative association between cadmium and abdominal and subcutaneous fat. • Girls: positive association between p,p′-DDE and indicators of abdominal fat.« less

Estimation of chloroform inhalation dose by other routes based on the relationship of area under the blood concentration-time curve (AUC)-inhalation dose to chloroform distribution in the blood of rats.

PubMed

Take, Makoto; Takeuchi, Tetsuya; Haresaku, Mitsuru; Matsumoto, Michiharu; Nagano, Kasuke; Yamamoto, Seigo; Takamura-Enya, Takeji; Fukushima, Shoji

2014-01-01

The present study investigated the time-course changes of concentration of chloroform (CHCl3) in the blood during and after exposure of male rats to CHCl3 by inhalation. Increasing the dose of CHCl3 in the inhalation exposed groups caused a commensurate increase in the concentration of CHCl3 in the blood and the area under the blood concentration-time curve (AUC). There was good correlation (r = 0.988) between the inhalation dose and the AUC/kg body weight. Based on the AUC/kg body weight-inhalation dose curve and the AUC/kg body weight after oral administration, inhalation equivalent doses of orally administered CHCl3 were calculated. Calculation of inhalation equivalent doses allows the body burden due to CHCl3 by inhalation exposure and oral exposure to be directly compared. This type of comparison facilitates risk assessment in humans exposed to CHCl3 by different routes. Our results indicate that when calculating inhalation equivalent doses of CHCl3, it is critical to include the AUC from the exposure period in addition to the AUC after the end of the exposure period. Thus, studies which measure the concentration of volatile organic compounds in the blood during the inhalation exposure period are crucial. The data reported here makes an important contribution to the physiologically based pharmacokinetic (PBPK) database of CHCl3 in rodents.

Overview of the Benzene and Other Toxics Exposure (BEE-TEX) Field Study.

PubMed

Olaguer, Eduardo P

2015-01-01

The Benzene and other Toxics Exposure (BEE-TEX) field study was an experimental campaign designed to demonstrate novel methods for measuring ambient concentrations of hazardous air pollutants (HAPs) in real time and to attribute these concentrations to quantified releases from specific emission points in industrial facilities while operating outside facility fence lines. BEE-TEX was conducted in February 2015 at three neighboring communities in the Houston Ship Channel of Texas, where a large number of petrochemical facilities are concentrated. The novel technologies deployed during BEE-TEX included: (1) tomographic remote sensing based on differential optical absorption spectroscopy; (2) real-time broadcasting of ambient air monitoring data over the World Wide Web; (3) real-time source attribution and quantification of HAP emissions based on either tomographic or mobile measurement platforms; and (4) the use of cultured human lung cells in vitro as portable indicators of HAP exposure.

Risk assessment of the cumulative acute exposure of Hungarian population to organophosphorus pesticide residues with regard to consumers of plant based foods.

PubMed

Zentai, Andrea; Szabó, István J; Kerekes, Kata; Ambrus, Árpád

2016-03-01

Based on the Hungarian pesticide residues monitoring data of the last five years and the consumption data collected within a 3-day dietary record survey in 2009 (more than 2 million pesticide residue results and almost 5000, 0-101-year-old consumers 3 non-consecutive-day personal fruit and vegetable consumption data), the cumulative acute exposure of organophosphorus pesticide residues was evaluated. The relative potency factor approach was applied, with acephate chosen as index compound. According to our conservative calculation method, applying the measured residues only, the 99.95% of the 99th percentiles of calculated daily intakes was at or below 87 μg/kgbwday, indicating that the cumulative acute exposure of the whole Hungarian population (including all age classes) to organophosphorus compounds was not a health concern. Copyright © 2016 Elsevier Ltd. All rights reserved.

Overview of the Benzene and Other Toxics Exposure (BEE-TEX) Field Study

PubMed Central

Olaguer, Eduardo P.

2015-01-01

The Benzene and other Toxics Exposure (BEE-TEX) field study was an experimental campaign designed to demonstrate novel methods for measuring ambient concentrations of hazardous air pollutants (HAPs) in real time and to attribute these concentrations to quantified releases from specific emission points in industrial facilities while operating outside facility fence lines. BEE-TEX was conducted in February 2015 at three neighboring communities in the Houston Ship Channel of Texas, where a large number of petrochemical facilities are concentrated. The novel technologies deployed during BEE-TEX included: (1) tomographic remote sensing based on differential optical absorption spectroscopy; (2) real-time broadcasting of ambient air monitoring data over the World Wide Web; (3) real-time source attribution and quantification of HAP emissions based on either tomographic or mobile measurement platforms; and (4) the use of cultured human lung cells in vitro as portable indicators of HAP exposure. PMID:26549972

Influence of salinity and temperature on acute toxicity of cadmium to Mysidopsis bahia molenock

DOE Office of Scientific and Technical Information (OSTI.GOV)

Voyer, R.A.; Modica, G.

1990-01-01

Acute toxicity tests were conducted to compare estimates of toxicity, as modified by salinity and temperature, based on response surface techniques with those derived using conventional test methods, and to compare effect of a single episodic exposure to cadmium as a function of salinity with that of continuous exposure. Regression analysis indicated that mortality following continuous 96-hr exposure is related to linear and quadratic effects of salinity and cadmium at 20 C, and to the linear and quadratic effects of cadmium only at 25C. LC50s decreased with increases in temperature and decreases in salinity. Based on the regression model developed,more » 96-hr LC50s ranged from 15.5 to 28.0 micro Cd/L at 10 and 30% salinities, respectively, at 25C; and from 47 to 85 microgram Cd/L at these salinities at 20C.« less

A New Stress-Based Model of Political Extremism

PubMed Central

Canetti-Nisim, Daphna; Halperin, Eran; Sharvit, Keren; Hobfoll, Stevan E.

2011-01-01

Does exposure to terrorism lead to hostility toward minorities? Drawing on theories from clinical and social psychology, we propose a stress-based model of political extremism in which psychological distress—which is largely overlooked in political scholarship—and threat perceptions mediate the relationship between exposure to terrorism and attitudes toward minorities. To test the model, a representative sample of 469 Israeli Jewish respondents was interviewed on three occasions at six-month intervals. Structural Equation Modeling indicated that exposure to terrorism predicted psychological distress (t1), which predicted perceived threat from Palestinian citizens of Israel (t2), which, in turn, predicted exclusionist attitudes toward Palestinian citizens of Israel (t3). These findings provide solid evidence and a mechanism for the hypothesis that terrorism introduces nondemocratic attitudes threatening minority rights. It suggests that psychological distress plays an important role in political decision making and should be incorporated in models drawing upon political psychology. PMID:22140275

Asthma caused by occupational exposures is common – A systematic analysis of estimates of the population-attributable fraction

PubMed Central

Torén, Kjell; Blanc, Paul D

2009-01-01

Background The aim of this paper is to highlight emerging data on occupational attributable risk in asthma. Despite well documented outbreaks of disease and the recognition of numerous specific causal agents, occupational exposures previously had been relegated a fairly minor role relative to other causes of adult onset asthma. In recent years there has been a growing recognition of the potential importance of asthma induced by work-related exposures Methods We searched Pub Med from June 1999 through December 2007. We identified six longitudinal general population-based studies; three case-control studies and eight cross-sectional analyses from seven general population-based samples. For an integrated analysis we added ten estimates prior to 1999 included in a previous review. Results The longitudinal studies indicate that 16.3% of all adult-onset asthma is caused by occupational exposures. In an overall synthesis of all included studies the overall median PAR value was 17.6%. Conclusion Clinicians should consider the occupational history when evaluating patients in working age who have asthma. At a societal level, these findings underscore the need for further preventive action to reduce the occupational exposures to asthma-causing agents. PMID:19178702

The role of toxicology to characterize biomarkers for agrochemicals with potential endocrine activities.

PubMed

Mantovani, Alberto; Maranghi, Francesca; La Rocca, Cinzia; Tiboni, Gian Mario; Clementi, Maurizio

2008-09-01

The paper discusses current knowledge and possible research priorities on biomarkers of exposure, effect and susceptibility for potential endocrine activities of agrochemicals (dicarboximides, ethylene bisdithiocarbammates, triazoles, etc.). Possible widespread, multiple-pathway exposure to agrochemicals highlights the need to assess internal exposure of animals or humans, which is the most relevant exposure measure for hazard and risk estimation; however, exposure data should be integrated by early indicators predictive of possible health effects, particularly for vulnerable groups such as mother-child pairs. Research need include: non-invasive biomarkers for children biomonitoring; novel biomarkers of total exposure to measure whole endocrine disrupter-related burden; characterization of biomarkers of susceptibility, including the role of markers of nutritional status; anchoring early molecular markers to established toxicological endpoints to support their predictivity; integrating "omics"-based approaches in a system-toxicology framework. As biomonitoring becomes increasingly important in the environment-and-health scenario, toxicologists can substantially contribute both to the characterization of new biomarkers and to the predictivity assessment and improvement of the existing ones.

[Effects of mere exposure on category evaluation measured by the IAT and the GNAT].

PubMed

Kawakami, Naoaki; Sato, Hirotsune; Yoshida, Fujio

2010-12-01

Based on mere exposure studies, we proposed that repeated exposure to stimuli belonging to a common category leads to a positive evaluation of that category. Furthermore, to investigate the implicit effects of mere exposure, indirect measures were used. In a series of experiments, participants were repeatedly exposed to mimetic words written in Japanese hiragana or katakana, or nothing (control). Then their evaluations of the category ("hiragana" or "katakana") were measured using indirect and direct measures. In Experiment 1 (Implicit Association Test; IAT), we adopted a traditional design using an exposure paradigm, such that the rating stimuli were identical to the exposed stimuli. Significant effects were observed for both measures. In Experiment 2 (IAT) and Experiment 3 (Go/No-go Association Task; GNAT), we used non-exposed stimuli that belonged to a common category as the rating stimuli. Significant effects were observed only for indirect measures. These results indicate that repeated exposure has unconscious positive effects on category evaluation. Theoretical and methodological implications of the findings are discussed.

Ecological risk of anthropogenic pollutants to reptiles: Evaluating assumptions of sensitivity and exposure.

PubMed

Weir, Scott M; Suski, Jamie G; Salice, Christopher J

2010-12-01

A large data gap for reptile ecotoxicology still persists; therefore, ecological risk assessments of reptiles usually incorporate the use of surrogate species. This necessitates that (1) the surrogate is at least as sensitive as the target taxon and/or (2) exposures to the surrogate are greater than that of the target taxon. We evaluated these assumptions for the use of birds as surrogates for reptiles. Based on a survey of the literature, birds were more sensitive than reptiles in less than 1/4 of the chemicals investigated. Dietary and dermal exposure modeling indicated that exposure to reptiles was relatively high, particularly when the dermal route was considered. We conclude that caution is warranted in the use of avian receptors as surrogates for reptiles in ecological risk assessment and emphasize the need to better understand the magnitude and mechanism of contaminant exposure in reptiles to improve exposure and risk estimation. Copyright © 2010 Elsevier Ltd. All rights reserved.

An improved ultraviolet spectral line list for the symbiotic star RR Telescopii

NASA Technical Reports Server (NTRS)

Doschek, G. A.; Feibelman, W. A.

1993-01-01

We have remeasured wavelengths and intensities of International Ultraviolet Explorer (IUE) spectra of the symbiotic star, RR Tel. The main work is centered on the long 820 minute exposure high-resolution spectrum obtained on 1983 June 18. The list is intended to serve as a source of improved intensities and wavelengths for the ultraviolet spectrum of this star. A complete line list with intensities based on this exposure has not been published previously. The strongest spectral lines are saturated in the 820 minute exposure, and intensities for these lines are mostly obtained from a 20 minute exposure obtained on the same day. A few intensities are obtained from other exposures if neither the 820 nor the 20 minute exposure is satisfactory. There are 111 lines in our list between 1168 and 1980 A. Some of the very weakest lines may not be real. These are indicated by question marks. We also discuss some of the plasma diagnostics available using spectral lines of O v and O iv.

'Only Fathers Smoking' Contributes the Most to Socioeconomic Inequalities: Changes in Socioeconomic Inequalities in Infants' Exposure to Second Hand Smoke over Time in Japan.

PubMed

Saito, Junko; Tabuchi, Takahiro; Shibanuma, Akira; Yasuoka, Junko; Nakamura, Masakazu; Jimba, Masamine

2015-01-01

Exposure to second hand smoke (SHS) is one of the major causes of premature death and disease among children. While socioeconomic inequalities exist for adult smoking, such evidence is limited for SHS exposure in children. Thus, this study examined changes over time in socioeconomic inequalities in infants' SHS exposure in Japan. This is a repeated cross-sectional study of 41,833 infants born in 2001 and 32,120 infants born in 2010 in Japan from nationally representative surveys using questionnaires. The prevalence of infants' SHS exposure was determined and related to household income and parental education level. The magnitudes of income and educational inequalities in infants' SHS exposure were estimated in 2001 and 2010 using both absolute and relative inequality indices. The prevalence of SHS exposure in infants declined from 2001 to 2010. The relative index of inequality increased from 0.85 (95% confidence interval [CI], 0.80 to 0.89) to 1.47 (95% CI, 1.37 to 1.56) based on income and from 1.22 (95% CI, 1.17 to 1.26) to 2.09 (95% CI, 2.00 to 2.17) based on education. In contrast, the slope index of inequality decreased from 30.9 (95% CI, 29.3 to 32.6) to 20.1 (95% CI, 18.7 to 21.5) based on income and from 44.6 (95% CI, 43.1 to 46.2) to 28.7 (95% CI, 27.3 to 30.0) based on education. Having only a father who smoked indoors was a major contributor to absolute income inequality in infants' SHS exposure in 2010, which increased in importance from 45.1% in 2001 to 67.0% in 2010. The socioeconomic inequalities in infants' second hand smoke exposure increased in relative terms but decreased in absolute terms from 2001 to 2010. Further efforts are needed to encourage parents to quit smoking and protect infants from second hand smoke exposure, especially in low socioeconomic households that include non-smoking mothers.

‘Only Fathers Smoking’ Contributes the Most to Socioeconomic Inequalities: Changes in Socioeconomic Inequalities in Infants’ Exposure to Second Hand Smoke over Time in Japan

PubMed Central

Saito, Junko; Tabuchi, Takahiro; Shibanuma, Akira; Yasuoka, Junko; Nakamura, Masakazu; Jimba, Masamine

2015-01-01

Background Exposure to second hand smoke (SHS) is one of the major causes of premature death and disease among children. While socioeconomic inequalities exist for adult smoking, such evidence is limited for SHS exposure in children. Thus, this study examined changes over time in socioeconomic inequalities in infants’ SHS exposure in Japan. Methods This is a repeated cross-sectional study of 41,833 infants born in 2001 and 32,120 infants born in 2010 in Japan from nationally representative surveys using questionnaires. The prevalence of infants’ SHS exposure was determined and related to household income and parental education level. The magnitudes of income and educational inequalities in infants’ SHS exposure were estimated in 2001 and 2010 using both absolute and relative inequality indices. Results The prevalence of SHS exposure in infants declined from 2001 to 2010. The relative index of inequality increased from 0.85 (95% confidence interval [CI], 0.80 to 0.89) to 1.47 (95% CI, 1.37 to 1.56) based on income and from 1.22 (95% CI, 1.17 to 1.26) to 2.09 (95% CI, 2.00 to 2.17) based on education. In contrast, the slope index of inequality decreased from 30.9 (95% CI, 29.3 to 32.6) to 20.1 (95% CI, 18.7 to 21.5) based on income and from 44.6 (95% CI, 43.1 to 46.2) to 28.7 (95% CI, 27.3 to 30.0) based on education. Having only a father who smoked indoors was a major contributor to absolute income inequality in infants’ SHS exposure in 2010, which increased in importance from 45.1% in 2001 to 67.0% in 2010. Conclusions The socioeconomic inequalities in infants’ second hand smoke exposure increased in relative terms but decreased in absolute terms from 2001 to 2010. Further efforts are needed to encourage parents to quit smoking and protect infants from second hand smoke exposure, especially in low socioeconomic households that include non-smoking mothers. PMID:26431400

Effects of a computer-based intervention program on the communicative functions of children with autism.

PubMed

Hetzroni, Orit E; Tannous, Juman

2004-04-01

This study investigated the use of computer-based intervention for enhancing communication functions of children with autism. The software program was developed based on daily life activities in the areas of play, food, and hygiene. The following variables were investigated: delayed echolalia, immediate echolalia, irrelevant speech, relevant speech, and communicative initiations. Multiple-baseline design across settings was used to examine the effects of the exposure of five children with autism to activities in a structured and controlled simulated environment on the communication manifested in their natural environment. Results indicated that after exposure to the simulations, all children produced fewer sentences with delayed and irrelevant speech. Most of the children engaged in fewer sentences involving immediate echolalia and increased the number of communication intentions and the amount of relevant speech they produced. Results indicated that after practicing in a controlled and structured setting that provided the children with opportunities to interact in play, food, and hygiene activities, the children were able to transfer their knowledge to the natural classroom environment. Implications and future research directions are discussed.

[Occupational exposure to hand-transmitted vibration in Poland].

PubMed

Harazin, Barbara; Zieliński, Grzegorz

2004-01-01

Occupational exposure to hand transmitted vibration may cause disorders in upper extremities known as hand-arm vibration syndrome. Therefore it is essential to know the sources of vibration, occupational groups exposed to vibration and the number of exposed workers. The aim of the study was to estimate the number of men and women exposed to hand-transmitted vibration in Poland. The completed questionnaires were obtained from 265 (80%) sanitary inspection stations. They included questions on: the name of workplaces, the name and the type of vibration sources, workers' gender, the number of workers exposed to vibration, indicating the extent of exposure measured against the three threshold limit values (< 0.5 TLV; 0.5 < TLV < 1 and > 1 TLV), and the number of workers exposed to hand-transmitted vibration not documented by measurements in a particular workplaces, indicating one of the three possible kinds of exposure (occasional, periodical and constant). The questionnaire data were based on measurements and analyses performed in 1997-2000. The results of the study showed that vibrating tools used by grinders, fitters, locksmiths, rammers, road workers, carpenters and smiths proved to be the most frequent sources of hand-transmitted vibration. It was revealed that 78.6% of operators of these tools were exposed to vibration exceeding 1 TLV. The study also indicated that 17,000 workers, including 1700 women, were exposed to vibration exceeding the threshold limit values.

Cancer incidence and magnetic field exposure in industries using resistance welding in Sweden.

PubMed

Håkansson, N; Floderus, B; Gustavsson, P; Johansen, C; Olsen, J H

2002-07-01

To investigate cancer incidence in workers exposed to high levels of extremely low frequency magnetic fields (ELF-MF). A cohort based on the engineering industry was established. Industries assumed to use resistance welding in production were chosen in order to increase the prevalence of high exposed subjects and to reduce the influence of confounding factors. All men and women employed in these branches during 1985-94 were selected, 537 692 men and 180 529 women. Occupation, based on census information from 1980, 1985, and 1990, was linked to a job exposure matrix on ELF-MF. Four exposure groups were used by stratifying on mean workday ELF-MF exposure, using the lowest exposure group as reference. Cancer incidence was obtained by linkage to the Swedish Cancer Registry. Men in the very high exposure group showed an increased incidence of tumours of the kidney, pituitary gland, and biliary passages and liver; for these cancer sites an exposure-response relation was indicated. Women in the very high exposure group showed an increased incidence of astrocytoma I-IV, with a clear exposure-response pattern. An association was suggested in the high exposure group only, for cancer of the corpus uteri and multiple myeloma. Decreased risks in the very high exposure group among men were found for cancer of the colon and connective tissue/muscle. The results on cancer of the liver, kidney, and pituitary gland among men are in accordance with previous observations. Regarding brain tumours and leukaemia, the outcome for women provided further support of an association. The hypothesis of a biological mechanism involving the endocrine system was partly supported.

Residential Exposure to Natural Background Radiation and Risk of Childhood Acute Leukemia in France, 1990-2009.

PubMed

Demoury, Claire; Marquant, Fabienne; Ielsch, Géraldine; Goujon, Stéphanie; Debayle, Christophe; Faure, Laure; Coste, Astrid; Laurent, Olivier; Guillevic, Jérôme; Laurier, Dominique; Hémon, Denis; Clavel, Jacqueline

2017-04-01

Exposures to high-dose ionizing radiation and high-dose rate ionizing radiation are established risk factors for childhood acute leukemia (AL). The risk of AL following exposure to lower doses due to natural background radiation (NBR) has yet to be conclusively determined. AL cases diagnosed over 1990-2009 (9,056 cases) were identified and their municipality of residence at diagnosis collected by the National Registry of Childhood Cancers. The Geocap study, which included the 2,763 cases in 2002-2007 and 30,000 population controls, was used for complementary analyses. NBR exposures were modeled on a fine scale (36,326 municipalities) based on measurement campaigns and geological data. The power to detect an association between AL and dose to the red bone marrow (RBM) fitting UNSCEAR (United Nations Scientific Committee on the Effects of Atomic Radiation) predictions was 92%, 45% and 99% for exposure to natural gamma radiation, radon and total radiation, respectively. AL risk, irrespective of subtype and age group, was not associated with the exposure of municipalities to radon or gamma radiation in terms of yearly exposure at age reached, cumulative exposure or RBM dose. There was no confounding effect of census-based socio-demographic indicators, or environmental factors (road traffic, high voltage power lines, vicinity of nuclear plants) related to AL in the Geocap study. Our findings do not support the hypothesis that residential exposure to NBR increases the risk of AL, despite the large size of the study, fine scale exposure estimates and wide range of exposures over France. However, our results at the time of diagnosis do not rule out a slight association with gamma radiation at the time of birth, which would be more in line with the recent findings in the UK and Switzerland.

R-LINE: A Line Source Dispersion Model for Near-Surface Releases

EPA Science Inventory

Based on Science Advisory Board and the National Research Councilrecommendations, EPA-ORD initiated research on near-road air quality andhealth effects. Field measurements indicated that exposures to traffic-emitted air pollutants near roads can be influenced by complexities of r...

AN OVERVIEW OF EPA'S HUMAN EXPOSURE PANEL STUDIES

EPA Science Inventory

In July 1997, the EPA Administrator issued new PM NAAQS that added PM2.5. The new standard is based largely on recent epidemiological investigations that indicated increased risks of mortality and morbidity are associated with higher concentrations of ambient particles. The new...

Developmental effects of methyl benzimidazolecarbamate following exposure during early pregnancy

EPA Science Inventory

Methyl 2-benzimidazolecarbamate (MBC) and its parent compound benomyl are used as agricultural fungicides. Both chemicals are embryotoxic if administered during organogenesis, and benomyl is teratogenic. Based on a previous study indicating a lack of maternal effects of MBC follo...

Changes in alcohol consumption after a natural disaster: a study of Norwegian survivors after the 2004 Southeast Asia tsunami

PubMed Central

2013-01-01

Background Many studies suggest that disaster exposure is related to a subsequent increase in alcohol consumption. Most of these studies have relied on retrospective self-reports to measure changes in alcohol use. The aim of the present study was to examine the association between disaster exposure and drinking behaviors more closely, analyzing data on both self-perceived changes in alcohol consumption and current drinking habits in groups with different extents of disaster exposure. Methods A sample of Norwegian adults (≥ 18 years) who resided in areas affected by the 2004 Southeast Asia tsunami (N = 899) were assessed by a postal questionnaire 6 months after the disaster. Based on detailed questions about experiences with the tsunami, participants were grouped according to their extent of disaster exposure. The Impact of Event Scale-Revised was applied to measure the level of post-traumatic stress. Participants were asked whether they had increased or decreased their alcohol consumption after the disaster. Moreover, weekly alcohol consumption and frequency of intoxication during the past month were used as indicators of current drinking behaviors. Results Severely exposed individuals more often reported changing their alcohol consumption compared with those who were less exposed. Severe exposure to the tsunami was associated with both a self-perceived increase (OR 21.38, 95% CI 2.91–157.28) and decrease in alcohol consumption (OR 7.41, 95% CI 1.74–31.51). The odds ratios decreased and were not significant when adjusting for post-traumatic stress symptoms. Weekly consumption and frequency of intoxication during the past month did not vary with extent of disaster exposure. Conclusions Our findings indicate a polarization effect of severe disaster exposure on self-perceived changes in alcohol consumption; that is, disaster exposure was associated with self-perceived increases and decreases in drinking. However, the absence of associations between disaster exposure and indicators of current drinking behaviors suggests that the observed polarization effect may be overestimated because of attribution and recall bias. PMID:23336627

Arsenic and diabetes: current perspectives.

PubMed

Huang, Chun Fa; Chen, Ya Wen; Yang, Ching Yao; Tsai, Keh Sung; Yang, Rong Sen; Liu, Shing Hwa

2011-09-01

Arsenic is a naturally occurring toxic metalloid of global concern. Many studies have indicated a dose-response relationship between accumulative arsenic exposure and the prevalence of diabetes mellitus (DM) in arseniasis-endemic areas in Taiwan and Bangladesh, where arsenic exposure occurs through drinking water. Epidemiological researches have suggested that the characteristics of arsenic-induced DM observed in arseniasis-endemic areas in Taiwan and Mexico are similar to those of non-insulin-dependent DM (Type 2 DM). These studies analyzed the association between high and chronic exposure to inorganic arsenic in drinking water and the development of DM, but the effect of exposure to low to moderate levels of inorganic arsenic on the risk of DM is unclear. Navas-Acien et al. recently proposed that a positive association existed between total urine arsenic and the prevalence of Type 2 DM in people exposed to low to moderate levels of arsenic. However, the diabetogenic role played by arsenic is still debated upon. An increase in the prevalence of DM has been observed among residents of highly arsenic-contaminated areas, whereas the findings from community-based and occupational studies in low-arsenic-exposure areas have been inconsistent. Recently, a population-based cross-sectional study showed that the current findings did not support an association between arsenic exposure from drinking water at levels less than 300 μg/L and a significantly increased risk of DM. Moreover, although the precise mechanisms for the arsenic-induced diabetogenic effect are still largely undefined, recent in vitro experimental studies indicated that inorganic arsenic or its metabolites impair insulin-dependent glucose uptake or glucose-stimulated insulin secretion. Nevertheless, the dose, the form of arsenic used, and the experimental duration in the in vivo studies varied greatly, leading to conflicting results and ambiguous interpretation of these data with respect to human exposure to arsenic in the environment. Moreover, the experimental studies were limited to the use of arsenic concentrations much higher than those relevant to human exposure. Further prospective epidemiological studies might help to clarify this controversy. The issues about environmental exposure assessment and appropriate biomarkers should also be considered. Here, we focus on the review of mechanism studies and discuss the currently available evidence and conditions for the association between environmental arsenic exposure and the development of DM. Copyright © 2011. Published by Elsevier B.V.

Digital radiography: are the manufacturers' settings too high? Optimisation of the Kodak digital radiography system with aid of the computed radiography dose index.

PubMed

Peters, Sinead E; Brennan, Patrick C

2002-09-01

Manufacturers offer exposure indices as a safeguard against overexposure in computed radiography, but the basis for recommended values is unclear. This study establishes an optimum exposure index to be used as a guideline for a specific CR system to minimise radiation exposures for computed mobile chest radiography, and compares this with manufacturer guidelines and current practice. An anthropomorphic phantom was employed to establish the minimum milliamperes consistent with acceptable image quality for mobile chest radiography images. This was found to be 2 mAs. Consecutively, 10 patients were exposed with this optimised milliampere value and 10 patients were exposed with the 3.2 mAs routinely used in the department of the study. Image quality was objectively assessed using anatomical criteria. Retrospective analyses of 717 exposure indices recorded over 2 months from mobile chest examinations were performed. The optimised milliampere value provided a significant reduction of the average exposure index from 1840 to 1570 ( p<0.0001). This new "optimum" exposure index is substantially lower than manufacturer guidelines of 2000 and significantly lower than exposure indices from the retrospective study (1890). Retrospective data showed a significant increase in exposure indices if the examination was performed out of hours. The data provided by this study emphasise the need for clinicians and personnel to consider establishing their own optimum exposure indices for digital investigations rather than simply accepting manufacturers' guidelines. Such an approach, along with regular monitoring of indices, may result in a substantial reduction in patient exposure.

Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models.

PubMed

Hoffmann, Sabine; Laurier, Dominique; Rage, Estelle; Guihenneuc, Chantal; Ancelet, Sophie

2018-01-01

Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies.

Shared and unshared exposure measurement error in occupational cohort studies and their effects on statistical inference in proportional hazards models

PubMed Central

Laurier, Dominique; Rage, Estelle

2018-01-01

Exposure measurement error represents one of the most important sources of uncertainty in epidemiology. When exposure uncertainty is not or only poorly accounted for, it can lead to biased risk estimates and a distortion of the shape of the exposure-response relationship. In occupational cohort studies, the time-dependent nature of exposure and changes in the method of exposure assessment may create complex error structures. When a method of group-level exposure assessment is used, individual worker practices and the imprecision of the instrument used to measure the average exposure for a group of workers may give rise to errors that are shared between workers, within workers or both. In contrast to unshared measurement error, the effects of shared errors remain largely unknown. Moreover, exposure uncertainty and magnitude of exposure are typically highest for the earliest years of exposure. We conduct a simulation study based on exposure data of the French cohort of uranium miners to compare the effects of shared and unshared exposure uncertainty on risk estimation and on the shape of the exposure-response curve in proportional hazards models. Our results indicate that uncertainty components shared within workers cause more bias in risk estimation and a more severe attenuation of the exposure-response relationship than unshared exposure uncertainty or exposure uncertainty shared between individuals. These findings underline the importance of careful characterisation and modeling of exposure uncertainty in observational studies. PMID:29408862

Exposure to crystalline silica in abrasive blasting operations where silica and non-silica abrasives are used.

PubMed

Radnoff, Diane L; Kutz, Michelle K

2014-01-01

Exposure to respirable crystalline silica is a hazard common to many industries in Alberta but particularly so in abrasive blasting. Alberta occupational health and safety legislation requires the consideration of silica substitutes when conducting abrasive blasting, where reasonably practicable. In this study, exposure to crystalline silica during abrasive blasting was evaluated when both silica and non-silica products were used. The crystalline silica content of non-silica abrasives was also measured. The facilities evaluated were preparing metal products for the application of coatings, so the substrate should not have had a significant contribution to worker exposure to crystalline silica. The occupational sampling results indicate that two-thirds of the workers assessed were potentially over-exposed to respirable crystalline silica. About one-third of the measurements over the exposure limit were at the work sites using silica substitutes at the time of the assessment. The use of the silica substitute, by itself, did not appear to have a large effect on the mean airborne exposure levels. There are a number of factors that may contribute to over-exposures, including the isolation of the blasting area, housekeeping, and inappropriate use of respiratory protective equipment. However, the non-silica abrasives themselves also contain silica. Bulk analysis results for non-silica abrasives commercially available in Alberta indicate that many contain crystalline silica above the legislated disclosure limit of 0.1% weight of silica per weight of product (w/w) and this information may not be accurately disclosed on the material safety data sheet for the product. The employer may still have to evaluate the potential for exposure to crystalline silica at their work site, even when silica substitutes are used. Limited tests on recycled non-silica abrasive indicated that the silica content had increased. Further study is required to evaluate the impact of product recycling on crystalline silica content for non-silica abrasives. Measurement of blaster exposure was challenging in this study as the blasters evaluated conducted this task intermittently throughout the work shift, frequently removing their blasting helmets. In spite of the challenges in accurately measuring blaster exposure, the measurements were still, for the most part, over the 8-h OEL. Further work is required to develop more effective sampling strategies to evaluate blaster exposure over the full work shift when task-based monitoring is not practical.

Tolerance for and potential indicators of second-hand smoke exposure among nonsmokers: a comparison of self-reported and cotinine verified second-hand smoke exposure based on nationally representative data.

PubMed

Jeong, Bo Yoon; Lim, Min Kyung; Yun, E Hwa; Oh, Jin-Kyoung; Park, Eun Young; Lee, Do-Hoon

2014-10-01

We assessed the extent to which self-reported exposure to SHS underestimates the actual exposure to SHS and what factors are associated with a tolerance for SHS exposure in the Korean setting where the smoke-free policy is incomplete. Information on socio-demographic characteristics, alcohol drinking and smoking was collected for 7948 nonsmokers aged ≥ 19 years from the fourth Korea National Health and Nutrition Examination Survey, 2008-2009. Self-reported and cotinine verified SHS exposures were compared. Potential factors associated with cotinine verified but not self-reported SHS exposures were assessed using a logistic regression model. Self-reported SHS exposure significantly underestimated the actual SHS exposure as determined by cotinine verification (kappa coefficient: 0.1066). At younger age, frequent alcohol drinking in females and a longer smoking duration in males were positively associated with cotinine verified exposure but not with the self-reported SHS exposure; they were also positively associated with cotinine verified exposure irrespective of self-reported SHS exposure. Our findings show a tolerance for smoking in Korea. The current partial ban on smoking does not fully protect people from exposure to SHS. Smoking should be banned in all public places. In addition, efforts to de-normalize smoking in the Korean culture need to be strengthened. Copyright © 2014 Elsevier Inc. All rights reserved.

Exposure- and flux-based assessment of ozone risk to sugarcane plants

NASA Astrophysics Data System (ADS)

Moura, Bárbara Baêsso; Hoshika, Yasutomo; Ribeiro, Rafael Vasconcelos; Paoletti, Elena

2018-03-01

Ozone (O3) is a toxic oxidative air pollutant, with significant detrimental effects on crops. Sugarcane (Saccharum spp.) is an important crop with no O3 risk assessment performed so far. This study aimed to assess O3 risk to sugarcane plants by using exposure-based indices (AOT40 and W126) based on O3 concentrations in the air, and the flux-based index (PODy, where y is a threshold of uptake) that considers leaf O3 uptake and the influence of environmental conditions on stomatal conductance (gsto). Two sugarcane genotypes (IACSP94-2094 and IACSP95-5000) were subjected to a 90-day Free-Air Controlled Experiment (FACE) exposure at three levels of O3 concentrations: ambient (Amb); Amb x1.2; and Amb x1.4. Total above-ground biomass (AGB), stalk biomass (SB) and leaf biomass (LB) were evaluated and the potential biomass production in a clean air was estimated by assuming a theoretical clean atmosphere at 10 ppb as 24 h O3 average. The Jarvis-type multiplicative algorithm was used to parametrize gsto including environmental factors i.e. air temperature, light intensity, air vapor pressure deficit, and minimum night-time temperature. Ozone exposure caused a negative impact on AGB, SB and LB. The O3 sensitivity of sugarcane may be related to its high gsto (∼535 mmol H2O m-2 s-1). As sugarcane is adapted to hot climate conditions, gsto was restricted when the current minimum air temperature (Tmin) was below ∼14 °C and the minimum night-time air temperature of the previous day (Tnmin) was below ∼7.5 °C. The flux-based index (PODy) performed better than the exposure-based indices in estimating O3 effect on biomass losses. We recommend a y threshold of 2 nmol m-2 s-1 to incorporate O3 effects on both AGB and SB and 1 nmol m-2 s-1 on LB. In order not to exceed 4% reduction in the growth of these two sugarcane genotypes, we recommend the following critical levels: 1.09 and 1.04 mmol m-2 POD2 for AGB, 0.91 and 0.96 mmol m-2 POD2 for SB, and 3.00 and 2.36 mmol m-2 POD1 for LB of IACSP95-5000 and IACSP94-2094, respectively.

Probabilistic modelling of human exposure to intense sweeteners in Italian teenagers: validation and sensitivity analysis of a probabilistic model including indicators of market share and brand loyalty.

PubMed

Arcella, D; Soggiu, M E; Leclercq, C

2003-10-01

For the assessment of exposure to food-borne chemicals, the most commonly used methods in the European Union follow a deterministic approach based on conservative assumptions. Over the past few years, to get a more realistic view of exposure to food chemicals, risk managers are getting more interested in the probabilistic approach. Within the EU-funded 'Monte Carlo' project, a stochastic model of exposure to chemical substances from the diet and a computer software program were developed. The aim of this paper was to validate the model with respect to the intake of saccharin from table-top sweeteners and cyclamate from soft drinks by Italian teenagers with the use of the software and to evaluate the impact of the inclusion/exclusion of indicators on market share and brand loyalty through a sensitivity analysis. Data on food consumption and the concentration of sweeteners were collected. A food frequency questionnaire aimed at identifying females who were high consumers of sugar-free soft drinks and/or of table top sweeteners was filled in by 3982 teenagers living in the District of Rome. Moreover, 362 subjects participated in a detailed food survey by recording, at brand level, all foods and beverages ingested over 12 days. Producers were asked to provide the intense sweeteners' concentration of sugar-free products. Results showed that consumer behaviour with respect to brands has an impact on exposure assessments. Only probabilistic models that took into account indicators of market share and brand loyalty met the validation criteria.

Effects of mobile phone exposure (GSM 900 and WCDMA/UMTS) on polysomnography based sleep quality: An intra- and inter-individual perspective.

PubMed

Danker-Hopfe, Heidi; Dorn, Hans; Bolz, Thomas; Peter, Anita; Hansen, Marie-Luise; Eggert, Torsten; Sauter, Cornelia

2016-02-01

Studies on effects of radio frequency-electromagnetic fields (RF-EMF) on the macrostructure of sleep so far yielded inconsistent results. This study investigated whether possible effects of RF-EMF exposure differ between individuals. In a double-blind, randomized, sham-controlled cross-over study possible effects of electromagnetic fields emitted by pulsed Global System for Mobile Communications (GSM) 900 and Wideband Code-Division Multiple Access (WCDMA)/Universal Mobile Telecommunications System (WCDMA/UMTS) devices on sleep were analysed. Thirty healthy young men (range 18-30 years) were exposed three times per exposure condition while their sleep was recorded. Sleep was evaluated according to the American Academy of Sleep Medicine standard and eight basic sleep variables were considered. Data analyses at the individual level indicate that RF-EMF effects are observed in 90% of the individuals and that all sleep variables are affected in at least four subjects. While sleep of participants was affected in various numbers, combinations of sleep variables and in different directions, showing improvements but also deteriorations, the only consistent finding was an increase of stage R sleep under GSM 900MHz exposure (9 of 30 subjects) as well as under WCDMA/UMTS exposure (10 of 30 subjects). The results underline that sleep of individuals can be affected differently. The observations found here may indicate an underlying thermal mechanism of RF-EMF on human REM sleep. Nevertheless, the effect of an increase in stage R sleep in one third of the individuals does not necessarily indicate a disturbance of sleep. Copyright © 2015 Elsevier Inc. All rights reserved.

Assessment of tolerant sunfish populations (Lepomis sp.) inhabiting selenium-laden coal ash effluents. 2. Tissue biochemistry evaluation.

PubMed

Lohner, T W; Reash, R J; Williams, M

2001-11-01

Sunfish were collected from a fly ash pond-receiving stream and an Ohio River reference site to assess biochemical responses to coal ash effluent exposure. Selenium levels in sunfish from the receiving stream were higher than toxic thresholds associated with adverse population effects and reproductive impairment. Tissue biochemistry was found to be indicative of metal exposure and effect, but varied widely. Liver glycogen was positively correlated with increased liver metal levels, indicating no adverse effect upon stored carbohydrate levels. Lipid levels decreased with increasing metals, indicating possible nutritional stress. Protein levels increased with increasing metal levels, possibly due to the synthesis of proteins to sequester the metals. ATPase, dUTPase, and alkaline phosphatase activity generally decreased with exposure to ash pond metals, but remained within normal physiological ranges. Fish condition factors and liver somatic indices were correlated with liver lipid levels, dUTPase activity, and gill ATPase and alkaline phosphatase activity. Exposure to coal ash effluents produced biochemical markers of exposure that were associated with fish condition indicators; however, the indices themselves were not significantly affected by effluent exposure.

Neuropsychological Effects of Low-Level Manganese Exposure in Welders

PubMed Central

Laohaudomchok, Wisanti; Lin, Xihong; Herrick, Robert F.; Fang, Shona C.; Cavallari, Jennifer M.; Shrairman, Ruth; Landau, Alexander; Christiani, David C.; Weisskopf, Marc G.

2011-01-01

While the neuropsychological effects of high manganese (Mn) exposure in occupational settings are well known, the effects of lower levels of exposure are less understood. In this study, we investigated the neuropsychological effects of lower level occupational Mn exposure in 46 male welders (mean age = 37.4, sd = 11.7 years). Each welders’ cumulative Mn exposure indices (Mn-CEI) for the past 12 months and total work history Mn exposure were constructed based on air Mn measurements and work histories. The association between these exposure indices and performance on cognitive, motor control, and psychological tests was examined. In addition, among a subset of welders (n=24) who completed the tests both before and after a work shift, we examined the association between cross-shift Mn exposure assessed from personal monitoring and acute changes in test scores. Mn exposures in this study (median = 12.9 μg/m3) were much lower, as compared to those observed in other similar studies. Increasing total Mn-CEI was significantly associated with slower reaction time on the continuous performance test (CPT; p<0.01), as well as worse mood for several scales on the Profile of Mood States (POMS; confused, tired, and a composite of tired and energetic, all p≤0.03). Increasing Mn-CEI over the previous 12 months was significantly associated with worse mood on the sad, tense, and confused POMS scales (all p≤0.03) and the association with worse CPT performance approached significance (p=0.10). Higher Mn exposure over the course of a workday was associated with worse performance on the CPT test across the day (p=0.06) as well as declines in fine motor control over the work-shift (p=0.04), adjusting for age and time between the 2 tests. Our study suggests that even at relatively low Mn exposure levels neuropsychological effects may manifest particularly with respect to attention, mood, and fine motor control. PMID:21192973

The prevalence, intensity, and assessment of craving for MDMA/ecstasy in recreational users.

PubMed

Davis, Alan K; Rosenberg, Harold

2014-01-01

This study evaluated the prevalence, intensity, and correlates of craving for MDMA/ecstasy among recreational users employing a new multi-item, self-report questionnaire reflecting experiences of desire, intention to use, and anticipated loss of control. Using a web-based data collection procedure, we recruited MDMA/ecstasy users (n = 240) to rate their agreement with eight craving statements immediately before and immediately following 90 seconds of exposure to either ecstasy-related or control stimuli. Participants then completed questionnaires to measure ecstasy refusal self-efficacy, passionate engagement in ecstasy use, substance use history, and demographic information. Fifty percent of participants indicated some level of agreement with at least two (out of eight) statements indicative of craving and 30% agreed at some level with six or more such statements. The questionnaire used to assess craving was internally consistent, unidimensional, and had excellent one-week test-retest reliability. Craving scores varied as a function of both cue exposure and frequency of ecstasy use, and were significantly associated with ecstasy-related attitudes. Recreational users of MDMA/ecstasy endorse some experiences indicative of craving for this drug, even though only a minority report intense craving following explicit cue exposure.

Towards a Neurobehavioral Profile of Fetal Alcohol Spectrum Disorders

PubMed Central

Mattson, Sarah N.; Roesch, Scott C.; Fagerlund, Åse; Autti-Rämö, Ilona; Jones, Kenneth Lyons; May, Philip A.; Adnams, Colleen M.; Konovalova, Valentina; Riley, Edward P.

2010-01-01

Background A primary goal of recent research is the development of neurobehavioral profiles that specifically define fetal alcohol spectrum disorders (FASD), which may assist differential diagnosis or improve treatment. In the current study we define a preliminary profile using neuropsychological data from a multisite study. Methods Data were collected using a broad neurobehavioral protocol from two sites of a multisite study of FASD. Subjects were children with heavy prenatal alcohol exposure and unexposed controls. The alcohol-exposed group included children with and with out fetal alcohol syndrome (FAS). From 547 neuropsychological, 22 variables were selected for analysis based on their ability to distinguish children with heavy prenatal alcohol exposure from nonexposed controls. These data were analyzed using latent profile analysis (LPA). Results The results indicated that a 2-class model best fit the data. The resulting profile was successful at distinguishing subjects with FAS from nonexposed controls without FAS with 92% overall accuracy; 87.8% of FAS cases and 95.7% of controls were correctly classified. The same analysis was repeated with children with heavy prenatal alcohol exposure but without FAS and non-exposed controls with similar results. The overall accuracy was 84.7%; 68.4% of alcohol-exposed cases and 95% of controls were correctly classified. In both analyses, the profile based on neuropsychological variables was more successful at distinguishing the groups than was IQ alone. Conclusions We used data from two sites of a multisite study and a broad neuropsychological test battery to determine a profile that could be used to accurately identify children affected by prenatal alcohol exposure. Results indicated that measures of executive function and spatial processing are especially sensitive to prenatal alcohol exposure. PMID:20569243

What Happens in Session Doesn't Stay in Session: Changes within Exposures Predict Subsequent Improvement and Dropout

PubMed Central

Norton, Peter J.; Hayes-Skelton, Sarah A.; Klenck, Suzanne C.

2011-01-01

Previous exposure therapy research has suggested potential differences in emotional processing at different points in treatment (Hayes, Hope, & Heimberg, 2008). For example, indicators of emotional processing may be more related to outcome during the later exposure sessions than during the initial session. This is consistent with a growing body of psychotherapy research highlighting the importance of timing and change processes across therapy. The current study examined whether the learning-but-not-benefiting hypothesis is observed in a group based intervention for clients with a range of anxiety disorders. It was hypothesized that activation and within session habituation during later, but not the initial exposure session, would be related to outcome, whereas activation and within session habituation during the first session would be related to dropout status. Results revealed that lower activation and less habituation during the first exposure was associated with increased treatment discontinuation. Second, lower peak and, to a lesser extent greater activation and habituation, during exposures were generally associated with better treatment outcomes. These findings highlight the importance of examining the complexities and timing of the exposure process. PMID:21419597

Inducible variation in anaerobic energy metabolism reflects hypoxia tolerance across the intertidal and subtidal distribution of the Pacific oyster (Crassostrea gigas).

PubMed

Meng, Jie; Wang, Ting; Li, Li; Zhang, Guofan

2018-07-01

Pacific oyster (Crassostrea gigas) distribute a steep gradient of environmental stress between intertidal and subtidal habits and provide insight into population-scale patterns and underlying processes of variation in physiological tolerance. In this study, 1-year-old-F 1 oysters, collected from subtidal and intertidal habitats, were obtained after common garden experiment. Genetic differentiation and physiological responses under air exposure were examined to determine whether they had evolved into local adapted subpopulations. Mortality rate, anaerobic glycolysis metabolism, and energy status indicated that oyster had initiated metabolism depression and anaerobic glycolysis metabolism in both intertidal and subtidal oysters under air exposure. However, the subtidal oysters displayed the larger energy metabolism depressions and the earlier anaerobic glycolysis responses. This may indicate that subtidal oysters were more sensitives to hypoxia stress, which may lead the higher mortality rate under long term of air exposure. Based on a common garden experimental design, we propose that this diversification may have a genetic background. Overall, the clear differences between intertidal and subtidal oysters under air exposure have provided an important reference for their aquaculture and transportation used in commercial production. Copyright © 2018. Published by Elsevier Ltd.

Development and early evaluation of the Virtual Iraq/Afghanistan exposure therapy system for combat-related PTSD.

PubMed

Rizzo, Albert Skip; Difede, JoAnn; Rothbaum, Barbara O; Reger, Greg; Spitalnick, Josh; Cukor, Judith; McLay, Rob

2010-10-01

Numerous reports indicate that the growing incidence of posttraumatic stress disorder (PTSD) in returning Operation Enduring Freedom (OEF)/Operation Iraqi Freedom (OIF) military personnel is creating a significant health care and economic challenge. These findings have served to motivate research on how to better develop and disseminate evidence-based treatments for PTSD. Virtual reality-delivered exposure therapy for PTSD has been previously used with reports of positive outcomes. The current paper will detail the development and early results from use of the Virtual Iraq/Afghanistan exposure therapy system. The system consists of a series of customizable virtual scenarios designed to represent relevant Middle Eastern contexts for exposure therapy, including a city and desert road convoy environment. The process for gathering user-centered design feedback from returning OEF/OIF military personnel and from a system deployed in Iraq (as was needed to iteratively evolve the system) will be discussed, along with a brief summary of results from an open clinical trial using Virtual Iraq with 20 treatment completers, which indicated that 16 no longer met PTSD checklist-military criteria for PTSD after treatment. © 2010 Association for Research in Nervous and Mental Disease.

A physiologically based pharmacokinetic model for ionic silver and silver nanoparticles

PubMed Central

Bachler, Gerald; von Goetz, Natalie; Hungerbühler, Konrad

2013-01-01

Silver is a strong antibiotic that is increasingly incorporated into consumer products as a bulk, salt, or nanosilver, thus potentially causing side-effects related to human exposure. However, the fate and behavior of (nano)silver in the human body is presently not well understood. In order to aggregate the existing experimental information, a physiologically based pharmacokinetic model (PBPK) was developed in this study for ionic silver and nanosilver. The structure of the model was established on the basis of toxicokinetic data from intravenous studies. The number of calibrated parameters was minimized in order to enhance the predictive capability of the model. We validated the model structure for both silver forms by reproducing exposure conditions (dermal, oral, and inhalation) of in vivo experiments and comparing simulated and experimentally assessed organ concentrations. Therefore, the percutaneous, intestinal, or pulmonary absorption fraction was estimated based on the blood silver concentration of the respective experimental data set. In all of the cases examined, the model could successfully predict the biodistribution of ionic silver and 15–150 nm silver nanoparticles, which were not coated with substances designed to prolong the circulatory time (eg, polyethylene glycol). Furthermore, the results of our model indicate that: (1) within the application domain of our model, the particle size and coating had a minor influence on the biodistribution; (2) in vivo, it is more likely that silver nanoparticles are directly stored as insoluble salt particles than dissolve into Ag+; and (3) compartments of the mononuclear phagocytic system play a minor role in exposure levels that are relevant for human consumers. We also give an example of how the model can be used in exposure and risk assessments based on five different exposure scenarios, namely dietary intake, use of three separate consumer products, and occupational exposure. PMID:24039420

A FLUORESCENCE-BASED SCREENING ASSAY FOR DNA DAMAGE INDUCED BY GENOTOXIC INDUSTRIAL CHEMICALS

EPA Science Inventory

The possibility of deliberate or accidental release of toxic chemicals in industrial, commercial or residential settings has indicated a need for rapid, cost-effective and versatile monitoring methods to prevent exposures to humans and ecosystems. Because many toxic industrial c...

A community survey of helicopter noise annoyance conducted under controlled noise exposure conditions

NASA Technical Reports Server (NTRS)

Fields, J. M.; Powell, C. A.

1985-01-01

Reactions to low numbers of helicopter noise events (less than 50 per day) were studied in a community setting. Community residents were repeatedly interviewed about daily noise annoyance reactions on days when helicopter noise exposures were, without the residents' knowledge, controlled. The effects of maximum noise level and number of noise events on helicopter noise annoyance are consistent with the principles contained in LEQ-based noise indices. The effect of the duration of noise events is also consistent with LEQ-based indices. After removing the effect of differences in noise levels (LEQ) there is not an important difference between reactions to impulsive and nonimpulsive types of helicopters. EPNL, where corrected for number of overflights, and LEQ are approximately equally successful in representing the characteristics of noise which are related to human response. The new type of design provided estimates of the parameters in a noise reaction model which would not obtained with a similar degree of precision from conventional study designs.

A new efficient method to monitor precocious puberty nationwide in France.

PubMed

Rigou, Annabel; Le Moal, Joëlle; Léger, Juliane; Le Tertre, Alain; Carel, Jean-Claude

2018-02-01

Clinical precocious puberty (PP) is a disease, reputed to be on the increase and suspected to be linked to endocrine disrupting chemicals (EDC) exposure. Population-based epidemiological data are lacking in France and scarce elsewhere. We accessed the feasibility of monitoring PP nationwide in France in this context, using a nationwide existing database, the French National Health Insurance Information System. Here, we present the method we used with a step-by-step approach to build and select the most suitable indicator. We built three indicators reflecting the incidence of idiopathic central precocious puberty (ICPP), the most frequent form of PP, and we compared these indicators according to their strengths and weaknesses with respect to surveillance purposes. Monitoring ICPP in France proved feasible using a Drug reimbursement indicator. Our method is cost efficient and highly relevant in public health surveillance. Our step-by-step approach proved helpful to achieve this project and could be proposed for assessing the feasibility of monitoring health outcomes of interest using existing data bases. What is known: • Precocious puberty (PP) is suspected to be related to EDC exposure and it is believed to be on the increase in France and in others countries. • Very few epidemiologic data on PP are currently available in the world at the national scale. What is new: • This is the first study describing a method to monitor the most frequent form of PP, idiopathic central PP (ICPP) nationwide in a cost-efficient way, using health insurance databases. • This cost-effective method will allow to estimate and monitor the incidence of ICPP in France and to analyze spatial variations at a very precise scale, which will be very useful to examine the role of environmental exposures, especially to EDCs.

Carbon disulfide exposure and neurotoxic sequelae among viscose rayon workers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aaserud, O.; Hommeren, O.J.; Tvedt, B.

1990-01-01

In Norway's only viscose rayon plant, carbon disulfide (CS2) concentrations in ambient air usually were between 30 and 50 mg/m3 during the first 23 years of production. From 1970/1971 until the factory was closed in 1982, corresponding values were 10-25 mg/m3. Through all of these years, high peak exposures of CS2 and H2S occurred. In 1986, 16 of the 24 men still at work in 1982 and with at least 10 years' experience in the spinning room agreed to participate in this study. Clinical neurological examination demonstrated abnormalities in 15; neuropsychological tests showed impairments of probable organic origin in 14.more » Thirteen had cerebral atrophy demonstrated by cerebral computed tomography (CT). Electromyography (EMG) was abnormal in six, neurography in 11. Regional cerebral blood flow measurements indicated flow asymmetries in eight, whereas Doppler investigation of the extracranial carotid and vertebral arteries, electroencephalography (EEG), and evoked response investigations were mostly normal. Based on these results and the exposure data, a diagnosis of CS2-induced encephalopathy was reached in eight workers; another six had an encephalopathy in which CS2 exposure was regarded as a partial cause. Correspondingly, seven had a neuropathy probably caused by CS2 exposure alone; in three others, CS2 was found to be the partial cause of a neuropathy. This indicates that long-term, relatively moderate exposure to CS2 in association with high peak exposures to CS2 and H2S involves a substantial risk of developing neurotoxic disease.« less

Looking at the other side of the coin: the search for possible biopositive cognitive effects of the exposure to 900 MHz GSM mobile phone radiofrequency radiation

PubMed Central

2014-01-01

Although exposure to electromagnetic radiation in radiofrequency range has caused a great deal of concern globally, radiofrequency radiation has many critical applications in both telecommunication and non-communication fields. The induction of adaptive response phenomena by exposure to radiofrequency radiation as either increased resistance to a subsequent dose of ionizing radiation or resistance to a bacterial infection has been reported recently. Interestingly, the potential beneficial effects of mobile phone radiofrequency radiation are not only limited to the induction of adaptive phenomena. It has previously been indicated that the visual reaction time of university students significantly decreased after a 10 min exposure to radiofrequency radiation emitted by a mobile phone. Furthermore, it has been revealed that occupational exposures to radar radiations decreased the reaction time in radar workers. Based on these findings, it can be hypothesized that in special circumstances, these exposures might lead to a better response of humans to different hazards. Other investigators have also provided evidence that confirms the induction of RF-induced cognitive benefits. Furthermore, some recent reports have indicated that RF radiation may play a role in protecting against cognitive impairment in Alzheimer’s disease. In this light, a challenging issue will arise if there are other RF-induced stimulating effects. It is also challenging to explore the potential applications of these effects. Further research may shed light on dark areas of the health effects of short and long-term human exposure to radiofrequency radiation. PMID:24843789

Looking at the other side of the coin: the search for possible biopositive cognitive effects of the exposure to 900 MHz GSM mobile phone radiofrequency radiation.

PubMed

Mortazavi, Seyed Ali Reza; Tavakkoli-Golpayegani, Ali; Haghani, Masoud; Mortazavi, Seyed Mohammad Javad

2014-01-01

Although exposure to electromagnetic radiation in radiofrequency range has caused a great deal of concern globally, radiofrequency radiation has many critical applications in both telecommunication and non-communication fields. The induction of adaptive response phenomena by exposure to radiofrequency radiation as either increased resistance to a subsequent dose of ionizing radiation or resistance to a bacterial infection has been reported recently. Interestingly, the potential beneficial effects of mobile phone radiofrequency radiation are not only limited to the induction of adaptive phenomena. It has previously been indicated that the visual reaction time of university students significantly decreased after a 10 min exposure to radiofrequency radiation emitted by a mobile phone. Furthermore, it has been revealed that occupational exposures to radar radiations decreased the reaction time in radar workers. Based on these findings, it can be hypothesized that in special circumstances, these exposures might lead to a better response of humans to different hazards. Other investigators have also provided evidence that confirms the induction of RF-induced cognitive benefits. Furthermore, some recent reports have indicated that RF radiation may play a role in protecting against cognitive impairment in Alzheimer's disease. In this light, a challenging issue will arise if there are other RF-induced stimulating effects. It is also challenging to explore the potential applications of these effects. Further research may shed light on dark areas of the health effects of short and long-term human exposure to radiofrequency radiation.

Estimation of Particulate Mass and Manganese Exposure Levels among Welders

PubMed Central

Hobson, Angela; Seixas, Noah; Sterling, David; Racette, Brad A.

2011-01-01

Background: Welders are frequently exposed to Manganese (Mn), which may increase the risk of neurological impairment. Historical exposure estimates for welding-exposed workers are needed for epidemiological studies evaluating the relationship between welding and neurological or other health outcomes. The objective of this study was to develop and validate a multivariate model to estimate quantitative levels of welding fume exposures based on welding particulate mass and Mn concentrations reported in the published literature. Methods: Articles that described welding particulate and Mn exposures during field welding activities were identified through a comprehensive literature search. Summary measures of exposure and related determinants such as year of sampling, welding process performed, type of ventilation used, degree of enclosure, base metal, and location of sampling filter were extracted from each article. The natural log of the reported arithmetic mean exposure level was used as the dependent variable in model building, while the independent variables included the exposure determinants. Cross-validation was performed to aid in model selection and to evaluate the generalizability of the models. Results: A total of 33 particulate and 27 Mn means were included in the regression analysis. The final model explained 76% of the variability in the mean exposures and included welding process and degree of enclosure as predictors. There was very little change in the explained variability and root mean squared error between the final model and its cross-validation model indicating the final model is robust given the available data. Conclusions: This model may be improved with more detailed exposure determinants; however, the relatively large amount of variance explained by the final model along with the positive generalizability results of the cross-validation increases the confidence that the estimates derived from this model can be used for estimating welder exposures in absence of individual measurement data. PMID:20870928

Application of the two-stage clonal expansion model in characterizing the joint effect of exposure to two carcinogens

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zielinski, J.M.; Krewski, D.

1992-12-31

In this paper, we describe application of the two-stage clonal expansion model to characterize the joint effect of exposure to two carcinogens. This biologically based model of carcinogenesis provides a useful framework for the quantitative description of carcinogenic risks and for defining agents that act as initiators, promoters, and completers. Depending on the mechanism of action, the agent-specific relative risk following exposure to two carcinogens can be additive, multiplicative, or supramultiplicative, with supra-additive relative risk indicating a synergistic effect between the two agents. Maximum-likelihood methods for fitting the two-stage clonal expansion model with intermittent exposure to two carcinogens are describedmore » and illustrated, using data on lung-cancer mortality among Colorado uranium miners exposed to both radon and tobacco smoke.« less

Levels of polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/Fs) and biphenyls (PCBs) in blood of informal e-waste recycling workers from Agbogbloshie, Ghana, and controls.

PubMed

Wittsiepe, Jürgen; Fobil, Julius N; Till, Holger; Burchard, Gerd-Dieter; Wilhelm, Michael; Feldt, Torsten

2015-06-01

The formation and environmental release of highly toxic organohalogen compounds associated with informal recycling of waste electric and electronic equipment (e-waste) is a growing problem at e-waste dumps/recycling sites (EWRSs) in many developing countries worldwide. We chose a cross-sectional study design to measure the internal exposure to polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) as well as polychlorinated biphenyls (PCBs) of individuals working on one of the largest EWRSs of Africa, located at Agbogbloshie, Accra, Ghana, and in controls from a suburb of Accra without direct exposure to EWRS activities. In whole blood samples of 21 age matched male exposed individuals (mean age: 24.7 years, SD 6.0) and 21 male controls (mean age: 24.4 years, SD 5.7) 17 PCDD/F congeners were determined. Moreover three indicator PCB congeners (#138, #153 and #180) were measured in blood of 39 exposed (mean age: 27.5 years, SD 11.7) and 19 non-exposed (mean age: 26.8 years, SD 9.7) patients. Besides a health examination, biometric and demographic data, residential and occupational history, occupational exposures and working conditions were recorded using a standardized questionnaire. In the exposed group, median PCDD/F-concentrations were 6.18 pg/g lipid base WHO2005-TEq (range: 2.1-42.7) and significantly higher compared to the control group with 4.60 pg/g lipid base WHO2005-TEq (range: 1.6-11.6). Concentrations were different for 2,3,7,8-TetraCDD, three HexaCDD and all 10 PCDF congeners, indicating a combustion pattern. Using a multivariate regression analysis exposure to EWRS activities was the most important determinant for PCDD/F exposure. Median PCB levels for the indicator congeners #138, #153 and #180 were 0.011, 0.019 and 0.008 μg/l whole blood (ranges: 0.002-0.18, 0.003-0.16, 0.002-0.078) in the exposed group and, surprisingly, significantly higher in the controls (0.037, 0.062 and 0.022; ranges: 0.005-0.46, 0.010-0.46, 0.004-0.21). In a multivariate regression approach e-waste related activities had no positive influence on internal PCB exposure, but rather the time living in Accra. The internal PCB exposure is in particular notable for a country where PCBs have historically never been produced or used. The impact of EWRS activities on organohalogen compound exposure of individuals working at and living in the surroundings of the Agbogbloshie EWRS, and the surprisingly high PCB exposure of people living in Accra not involved in e-waste activities require further investigation. Copyright © 2015 Elsevier Ltd. All rights reserved.

The efficacy of protoporphyrin as a predictive biomarker for lead exposure in canvasback ducks: effect of sample storage time

USGS Publications Warehouse

Franson, J.C.; Hohman, W.L.; Moore, J.L.; Smith, M.R.

1996-01-01

We used 363 blood samples collected from wild canvasback dueks (Aythya valisineria) at Catahoula Lake, Louisiana, U.S.A. to evaluate the effect of sample storage time on the efficacy of erythrocytic protoporphyrin as an indicator of lead exposure. The protoporphyrin concentration of each sample was determined by hematofluorometry within 5 min of blood collection and after refrigeration at 4 °C for 24 and 48 h. All samples were analyzed for lead by atomic absorption spectrophotometry. Based on a blood lead concentration of ≥0.2 ppm wet weight as positive evidence for lead exposure, the protoporphyrin technique resulted in overall error rates of 29%, 20%, and 19% and false negative error rates of 47%, 29% and 25% when hematofluorometric determinations were made on blood at 5 min, 24 h, and 48 h, respectively. False positive error rates were less than 10% for all three measurement times. The accuracy of the 24-h erythrocytic protoporphyrin classification of blood samples as positive or negative for lead exposure was significantly greater than the 5-min classification, but no improvement in accuracy was gained when samples were tested at 48 h. The false negative errors were probably due, at least in part, to the lag time between lead exposure and the increase of blood protoporphyrin concentrations. False negatives resulted in an underestimation of the true number of canvasbacks exposed to lead, indicating that hematofluorometry provides a conservative estimate of lead exposure.

Explaining variability in first grazing season heifer growth combining individually measured parasitological and clinical indicators with exposure to gastrointestinal nematode infection based on grazing management practice.

PubMed

Merlin, Aurélie; Chauvin, Alain; Madouasse, Aurélien; Froger, Sébastien; Bareille, Nathalie; Chartier, Christophe

2016-07-30

The objective of our study was to explain the variability of average daily weight gain (ADWG) due to gastrointestinal nematode (GIN) infection for 291 non treated first grazing season (FGS) heifers, from 12 independent groups in the western part of France, by combining parasitological and clinical indicators at individual level and grazing management indicators at group level. Parasitological indicators were faecal egg count (FEC), anti Ostertagia ostertagi antibody level (Ostertagia ODR), and pepsinogen level. Clinical indicators were diarrhea score (DISCO) and breech soiling score (BSS). At group level, grazing management practice (GMP), based on three variables (supplementation, month of turnout, grazing season duration), was clustered into three categories reflecting low, medium or high exposure (EXP) to GIN. Depending on the groups, turnout was from mid-March to early July and housing was from mid-October to late November, with a FGS duration ranging from 4 to 8.4 months. At turnout, the mean age of heifers was 8 months (range: 6-16 months) and they weighed between 175 and 268kg. In each GMP category, FEC significantly decreased between the mid-season and the housing, while Ostertagia ODR and pepsinogen level increased gradually throughout the grazing season. In contrast, clinical indicators did not show any seasonal variation. In a multivariate linear model, 22% of the ADWG variability was significantly explained by two individual indicators (Ostertagia ODR: 12.6%, DISCO: 4.8%) and by the group indicator (GMP category: 4.8%). ADWG losses due to GIN exposure (Ostertagia ODR) were estimated up to 39kg per heifer for the overall grazing season. For groups within the low EXP category the difference between animals with low (<697g/day) or high (>697g/day) ADWG was explained by the clinical indicator DISCO. In contrast, for groups within the medium and high EXP categories this difference was explained by a parasitological indicator (Ostertagia ODR). This study highlighted the value of combining both grazing management (group level) and parasitological (individual level) indicators to assess the impact of GIN on ADWG of FGS heifers. As a result, this combination might allow a better discrimination of animals or groups that may be in need of treatment in a targeting selective treatment approach. Copyright © 2016 Elsevier B.V. All rights reserved.

BME Estimation of Residential Exposure to Ambient PM10 and Ozone at Multiple Time Scales

PubMed Central

Yu, Hwa-Lung; Chen, Jiu-Chiuan; Christakos, George; Jerrett, Michael

2009-01-01

Background Long-term human exposure to ambient pollutants can be an important contributing or etiologic factor of many chronic diseases. Spatiotemporal estimation (mapping) of long-term exposure at residential areas based on field observations recorded in the U.S. Environmental Protection Agency’s Air Quality System often suffer from missing data issues due to the scarce monitoring network across space and the inconsistent recording periods at different monitors. Objective We developed and compared two upscaling methods: UM1 (data aggregation followed by exposure estimation) and UM2 (exposure estimation followed by data aggregation) for the long-term PM10 (particulate matter with aerodynamic diameter ≤ 10 μm) and ozone exposure estimations and applied them in multiple time scales to estimate PM and ozone exposures for the residential areas of the Health Effects of Air Pollution on Lupus (HEAPL) study. Method We used Bayesian maximum entropy (BME) analysis for the two upscaling methods. We performed spatiotemporal cross-validations at multiple time scales by UM1 and UM2 to assess the estimation accuracy across space and time. Results Compared with the kriging method, the integration of soft information by the BME method can effectively increase the estimation accuracy for both pollutants. The spatiotemporal distributions of estimation errors from UM1 and UM2 were similar. The cross-validation results indicated that UM2 is generally better than UM1 in exposure estimations at multiple time scales in terms of predictive accuracy and lack of bias. For yearly PM10 estimations, both approaches have comparable performance, but the implementation of UM1 is associated with much lower computation burden. Conclusion BME-based upscaling methods UM1 and UM2 can assimilate core and site-specific knowledge bases of different formats for long-term exposure estimation. This study shows that UM1 can perform reasonably well when the aggregation process does not alter the spatiotemporal structure of the original data set; otherwise, UM2 is preferable. PMID:19440491

Risk Factors for Smoking in Rural Women: The Role of Gender-Based Sexual and Intimate Partner Violence

PubMed Central

Nemeth, Julianna M.; Bonomi, Amy E.; Lu, Bo; Lomax, Richard G.; Wewers, Mary Ellen

2016-01-01

Abstract Background: Women living in Ohio Appalachia experience cervical cancer at disproportionately high rates. Intimate partner and sexual gender-based violence (GBV) and smoking are independent risk factors for cervical cancer and interact to heighten risk. Appalachian women smoke at higher rates than other Ohio women, but little is known about GBV exposure in the region. The purpose of this study was to establish prevalence of women's exposure to GBV in Ohio Appalachia and examine the association between GBV and smoking among women in the region. Methods: A two-phase address-based random sampling approach was used in three purposefully selected Ohio Appalachian counties to identify women to complete an interviewer administered cross-sectional survey (n = 398). The primary exposure variable was GBV Index Score, a 4 level indices representing increasing exposure to eight abuse types. Correlation analysis and logistic regression were used to examine smoking correlations and risk. Results: Almost 57% of women in the three selected Ohio Appalachian counties experienced GBV, with rate increasing to 77.5% among current smokers. The distribution of the GBV Exposure Index Score was significantly different across smoking status (p < = 0.0001), with exposure of GBV increasing when moving from never, to former, to current smokers. When controlling for depression, age, and adult socioeconomic position, GBV Exposure Index was significantly associated with current smoking behavior (OR:1.62, 95% CI [1.21–2.17]). Discussion: Professionals working to reduce disparate disease burden among women in Ohio Appalachia should consider the role GBV plays in health behavior and behavioral change interventions, including smoking and smoking cessation. PMID:27548468

Do occupational exposures to vinyl chloride cause hepatocellular carcinoma and cirrhosis?

PubMed

Lotti, Marcello

2017-05-01

Controversy exists about the association between occupational exposures to vinyl chloride and hepatocellular carcinoma and cirrhosis. Two large multicentre mortality cohort studies, one American and another European, reported higher mortality for primary cancer of liver and biliary tract. However, the American study was not able to rule out misclassification, because based on death certificates and under the heading primary liver cancers, some angiosarcomas, the typical neoplasia associated with vinyl chloride, may have been included. The American study does not report on cirrhosis mortality. The European study also reports higher mortality of primary liver cancer, but contrary to the American study in a further analysis based on 10 verified cases of hepatocellular carcinoma, an exposure-response trend with duration of employment and with cumulative exposure to vinyl chloride was detected. A smaller cohort belonging to this multicentre cohort confirmed these results. Meta-analyses based on the two large cohorts concluded for a small excess of primary liver cancer, although misclassification could not be ruled out. Excess risk of cirrhosis was reported in the European cohort, in a subcohort and in a cross-sectional study. However, a meta-analysis did not confirm this excess. Several critical appraisals of the literature reached antithetical conclusions about hepatocellular carcinoma, cirrhosis and occupational exposures to vinyl chloride. For both hepatocellular carcinoma and cirrhosis, a study suggests an additive and multiplicative effect of vinyl chloride exposure with viral hepatitis and alcohol consumption respectively. Pathology reports seem to indicate a possible development of hepatocellular carcinoma but not of cirrhosis after high exposures to vinyl chloride. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Diesel Exhaust Exposure and the Risk of Lung Cancer—A Review of the Epidemiological Evidence

PubMed Central

Sun, Yi; Bochmann, Frank; Nold, Annette; Mattenklott, Markus

2014-01-01

To critically evaluate the association between diesel exhaust (DE) exposure and the risk of lung cancer, we conducted a systematic review of published epidemiological evidences. To comprehensively identify original studies on the association between DE exposure and the risk of lung cancer, literature searches were performed in literature databases for the period between 1970 and 2013, including bibliographies and cross-referencing. In total, 42 cohort studies and 32 case-control studies were identified in which the association between DE exposures and lung cancer was examined. In general, previous studies suffer from a series of methodological limitations, including design, exposure assessment methods and statistical analysis used. A lack of objective exposure information appears to be the main problem in interpreting epidemiological evidence. To facilitate the interpretation and comparison of previous studies, a job-exposure matrix (JEM) of DE exposures was created based on around 4,000 historical industrial measurements. The values from the JEM were considered during interpretation and comparison of previous studies. Overall, neither cohort nor case-control studies indicate a clear exposure-response relationship between DE exposure and lung cancer. Epidemiological studies published to date do not allow a valid quantification of the association between DE and lung cancer. PMID:24473109

The effects of magnetic fields exposure on relative permittivity of saline solutions measured by a high resolution SPR system

PubMed Central

Jiang, Li; Zhao, Xinyuan; Fei, Yue; Yu, Dongdong; Qian, Jun; Tong, Jinguang; Chen, Guangdi; He, Sailing

2016-01-01

A measurement system for the relative permittivity of a physiological solution under 50 Hz magnetic fields (MF) is presented. It is based on a phase-sensitive surface plasmon resonance (SPR) system. Relative permittivity was analyzed for different solute concentrations of sodium chloride under various MF exposure parameters. We found that MF exposure at 0.2–4.0 mT step-wise decreased significantly the SPR phase signal of a 0.9% sodium chloride solution while 0.1 mT of MF exposure did not. The decreases in the SPR phase signal depended on the duration of MF exposure, and the signal reached a plateau after 15 min of exposure. Interestingly, the decreased SPR phase signal showed a gradual increase and approached the background level when the exposure was drawn off. In addition, we found that the response of the sodium chloride solution to MF also depended on its concentration. In brief, the relative permittivity of sodium chloride in solutions appears to be practically affected by 50 Hz MF exposure. Our data indicates that the relative permittivity of the saline solution influenced by MF exposure should be considered when investigating the biological effects of MF exposure on organisms in experimental study. PMID:27121618

Does the form or the amount of exposure make a difference in the cognitive-behavioral therapy treatment of social phobia?

PubMed

Borgeat, François; Stankovic, Miroslava; Khazaal, Yasser; Rouget, Beatrice Weber; Baumann, Marie-Claude; Riquier, Françoise; O'Connor, Kieron; Jermann, Françoise; Zullino, Daniele; Bondolfi, Guido

2009-07-01

Exposure is considered to be an essential ingredient of cognitive-behavioral therapy treatment of social phobia and of most anxiety disorders. To assess the impact of the amount of exposure on outcome, 30 social phobic patients were randomly allocated to 1 of 2 group treatments of 8 weekly sessions: Self-Focused Exposure Therapy which is based essentially on prolonged exposure to public speaking combined with positive feedback or a more standard cognitive and behavioral method encompassing psychoeducation, cognitive work, working through exposure hierarchies of feared situations for exposure within and outside the group. The results show that the 2 methods led to significant and equivalent symptomatic improvements which were maintained at 1-year follow-up. There was a more rapid and initially more pronounced decrease in negative cognitions with the Self-Focused Exposure Therapy, which included no formal cognitive work, than with the more standard approach in which approximately a third of the content was cognitive. In contrast, decrease in social avoidance was more persistent with standard cognitive-behavior therapy which involved less exposure. The results indicate that positive cognitive change can be achieved more rapidly with non cognitive methods while avoidance decreases more reliably with a standard approach rather than an approach with an exclusive focus on exposure.

A mechanistic model of environmental oxygen influence on the deterministic effects to human skin from space radiations

NASA Astrophysics Data System (ADS)

Flores-McLaughlin, John

During human spaceflight missions, controlled variation of atmospheric pressure and oxygen concentration from a sea-level based normal to hyperoxic levels may occur as part of operational procedure. This activity is of interest because it provides the relevant radiation exposure and dynamic oxygen concentration parameters that may lead to varying radiation sensitivity in the skin and other organs. Tumor hypoxia has been indicated as a primary factor in the decrease in efficacy of radiation therapy. These oxygen concentration effects have been largely demonstrated with low-LET radiations and to a lesser degree with high-LET primary radiations such as protons and heavy ions common in space exposure. In order to analyze the variation of oxygen concentration in human skin from spaceflight activities, a mathematical model of oxygen transport through the human cardiorespiratory system with pulmonary and cutaneous intake was implemented. Oxygen concentration was simulated at the various skin layers, from dermis to epidermis. Skin surface radiation doses and spectra from relatively high flux Solar Particle Events (SPEs) were calculated by the PHITS radiation transport code over a range of spacecraft and spacesuit thicknesses in terms of aluminum equivalence. A series of anatomical skin and shielding thicknesses were chosen to encompass the scope of radiation exposure levels as indicated by existing NASA skin phantom studies. To model the influence of oxygen with radiation exposure, microdosimetric oxygen fixation simulations were implemented using the Monte-Carlo-Damage-Simulation (MCDS) code. From these outputs, occurrence of DNA double strand breaks (DSBs) and relative biological effect (RBE) from radiation exposure with oxygen concentration dependence was established and correlated to spaceflight activities. It was determined that minimal but observable oxygen concentration transients occur in skin during environmental oxygen changes in spaceflight. The most significant transients occurred in the thickest epidermal layers with relatively high amounts of diffusion. Accordingly, these thickest epidermal layers also showed the greatest spaceflight induced transients of RBE relative to sea-level based atmosphere exposures.

Exploring DSM-5 criterion A in Acute Stress Disorder symptoms following natural disaster.

PubMed

Lavenda, Osnat; Grossman, Ephraim S; Ben-Ezra, Menachem; Hoffman, Yaakov

2017-10-01

The present study examines the DSM-5 Acute Stress Disorder (ASD) diagnostic criteria of exposure, in the context of a natural disaster. The study is based on the reports of 1001 Filipinos following the aftermath of super typhoon Haiyan in 2013. Participants reported exposure to injury, psychological distress and ASD symptoms. Findings indicated the association of criterion A with the prevalence of meeting all other ASD diagnostic criteria and high psychological distress. The diagnostic properties of Criterion A are discussed. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of Potential Exposure to Metals in Laundered Shop Towels

PubMed Central

Greenberg, Grace; Beck, Barbara D.

2013-01-01

We reported in 2003 that exposure to metals on laundered shop towels (LSTs) could exceed toxicity criteria. New data from LSTs used by workers in North America document the continued presence of metals in freshly laundered towels. We assessed potential exposure to metals based on concentrations of metals on the LSTs, estimates of LST usage by employees, and the transfer of metals from LST-to-hand, hand-to-mouth, and LST-to-lip, under average- or high-exposure scenarios. Exposure estimates were compared to toxicity criteria. Under an average-exposure scenario (excluding metals' data outliers), exceedances of the California Environmental Protection Agency, U.S. Environmental Protection Agency, and the Agency for Toxic Substances and Disease Registry toxicity criteria may occur for aluminum, cadmium, cobalt, copper, iron, and lead. Calculated intakes for these metals were up to more than 400-fold higher (lead) than their respective toxicity criterion. For the high-exposure scenario, additional exceedances may occur, and high-exposure intakes were up to 1,170-fold higher (lead) than their respective toxicity criterion. A sensitivity analysis indicated that alternate plausible assumptions could increase or decrease the magnitude of exceedances, but were unlikely to eliminate certain exceedances, particularly for lead. PMID:24453472

Web-Based Survey Application to Collect Contextually Relevant Geographic Data With Exposure Times: Application Development and Feasibility Testing

PubMed Central

Tobin, Karin; Rudolph, Jonathan; Latkin, Carl

2018-01-01

Background Although studies that characterize the risk environment by linking contextual factors with individual-level data have advanced infectious disease and substance use research, there are opportunities to refine how we define relevant neighborhood exposures; this can in turn reduce the potential for exposure misclassification. For example, for those who do not inject at home, injection risk behaviors may be more influenced by the environment where they inject than where they live. Similarly, among those who spend more time away from home, a measure that accounts for different neighborhood exposures by weighting each unique location proportional to the percentage of time spent there may be more correlated with health behaviors than one’s residential environment. Objective This study aimed to develop a Web-based application that interacts with Google Maps application program interfaces (APIs) to collect contextually relevant locations and the amount of time spent in each. Our analysis examined the extent of overlap across different location types and compared different approaches for classifying neighborhood exposure. Methods Between May 2014 and March 2017, 547 participants enrolled in a Baltimore HIV care and prevention study completed an interviewer-administered Web-based survey that collected information about where participants were recruited, worked, lived, socialized, injected drugs, and spent most of their time. For each location, participants gave an address or intersection which they confirmed using Google Map and Street views. Geographic coordinates (and hours spent in each location) were joined to neighborhood indicators by Community Statistical Area (CSA). We computed a weighted exposure based on the proportion of time spent in each unique location. We compared neighborhood exposures based on each of the different location types with one another and the weighted exposure using analysis of variance with Bonferroni corrections to account for multiple comparisons. Results Participants reported spending the most time at home, followed by the location where they injected drugs. Injection locations overlapped most frequently with locations where people reported socializing and living or sleeping. The least time was spent in the locations where participants reported earning money and being recruited for the study; these locations were also the least likely to overlap with other location types. We observed statistically significant differences in neighborhood exposures according to the approach used. Overall, people reported earning money in higher-income neighborhoods and being recruited for the study and injecting in neighborhoods with more violent crime, abandoned houses, and poverty. Conclusions This analysis revealed statistically significant differences in neighborhood exposures when defined by different locations or weighted based on exposure time. Future analyses are needed to determine which exposure measures are most strongly associated with health and risk behaviors and to explore whether associations between individual-level behaviors and neighborhood exposures are modified by exposure times. PMID:29351899

Flat-panel detector, CCD cameras, and electron-beam-tube-based video for use in portal imaging

NASA Astrophysics Data System (ADS)

Roehrig, Hans; Tang, Chuankun; Cheng, Chee-Way; Dallas, William J.

1998-07-01

This paper provides a comparison of some imaging parameters of four portal imaging systems at 6 MV: a flat panel detector, two CCD cameras and an electron beam tube based video camera. Measurements were made of signal and noise and consequently of signal-to-noise per pixel as a function of the exposure. All systems have a linear response with respect to exposure, and with the exception of the electron beam tube based video camera, the noise is proportional to the square-root of the exposure, indicating photon-noise limitation. The flat-panel detector has a signal-to-noise ratio, which is higher than that observed with both CCD-Cameras or with the electron beam tube based video camera. This is expected because most portal imaging systems using optical coupling with a lens exhibit severe quantum-sinks. The measurements of signal-and noise were complemented by images of a Las Vegas-type aluminum contrast detail phantom, located at the ISO-Center. These images were generated at an exposure of 1 MU. The flat-panel detector permits detection of Aluminum holes of 1.2 mm diameter and 1.6 mm depth, indicating the best signal-to-noise ratio. The CCD-cameras rank second and third in signal-to- noise ratio, permitting detection of Aluminum-holes of 1.2 mm diameter and 2.2 mm depth (CCD_1) and of 1.2 mm diameter and 3.2 mm depth (CCD_2) respectively, while the electron beam tube based video camera permits detection of only a hole of 1.2 mm diameter and 4.6 mm depth. Rank Order Filtering was applied to the raw images from the CCD-based systems in order to remove the direct hits. These are camera responses to scattered x-ray photons which interact directly with the CCD of the CCD-Camera and generate 'Salt and Pepper type noise,' which interferes severely with attempts to determine accurate estimates of the image noise. The paper also presents data on the metal-phosphor's photon gain (the number of light-photons per interacting x-ray photon).

Pathogen Treatment Guidance and Monitoring Approaches fro On-Site Non-Potable Water Reuse

EPA Science Inventory

On-site non-potable water reuse is increasingly used to augment water supplies, but traditional fecal indicator approaches for defining and monitoring exposure risks are limited when applied to these decentralized options. This session emphasizes risk-based modeling to define pat...

Genomic effects of androstenedione and sex-specific liver cancer susceptibility in mice

EPA Science Inventory

Current strategies for predicting carcinogenic mode of action for nongenotoxic chemicals are based on identification of early key events in toxicity pathways. The goal of this study was to evaluate short-term key event indicators resulting from exposure to androstenedione (A4), a...

Posttraumatic Resilience in Former Ugandan Child Soldiers

ERIC Educational Resources Information Center

Klasen, Fionna; Oettingen, Gabriele; Daniels, Judith; Post, Manuela; Hoyer, Catrin; Adam, Hubertus

2010-01-01

The present research examines posttraumatic resilience in extremely exposed children and adolescents based on interviews with 330 former Ugandan child soldiers (age = 11-17, female = 48.5%). Despite severe trauma exposure, 27.6% showed posttraumatic resilience as indicated by the absence of posttraumatic stress disorder, depression, and clinically…

Differences in Neural Correlates of Speech Perception in 3 Month Olds at High and Low Risk for Autism Spectrum Disorder.

PubMed

Edwards, Laura A; Wagner, Jennifer B; Tager-Flusberg, Helen; Nelson, Charles A

2017-10-01

In this study, we investigated neural precursors of language acquisition as potential endophenotypes of autism spectrum disorder (ASD) in 3-month-old infants at high and low familial ASD risk. Infants were imaged using functional near-infrared spectroscopy while they listened to auditory stimuli containing syllable repetitions; their neural responses were analyzed over left and right temporal regions. While female low risk infants showed initial neural activation that decreased over exposure to repetition-based stimuli, potentially indicating a habituation response to repetition in speech, female high risk infants showed no changes in neural activity over exposure. This finding may indicate a potential neural endophenotype of language development or ASD specific to females at risk for the disorder.

Parental knowledge of radiation exposure in medical imaging used in the pediatric emergency department.

PubMed

Hartwig, Hans-David R; Clingenpeel, Joel; Perkins, Amy M; Rose, Whitney; Abdullah-Anyiwo, Joel

2013-06-01

We sought to quantify the knowledge base among parents and legal guardians presenting to our pediatric emergency department regarding radiation exposure during medical imaging and potential risks to children resulting from ionizing radiation. We sought to examine if a child's previous exposure to medical imaging changed caregiver knowledge base and discern caregivers' preference for future education on this topic. A prospective convenience sample survey was performed of caregivers who presented with their child to our tertiary pediatric emergency department. Parents or legal guardians (18-89 years) who accompanied a child (0-17 years) were eligible for inclusion and approached for enrollment. A structured questionnaire was administered by trained interviewers, and a chart review was conducted to ascertain if their child had a history of previous imaging. Sixty percent of caregivers interviewed (n = 205 of 340) did not associate any long-term negative effects with medical imaging. Among participants who did express a perceived risk from medical imaging radiation exposure, only 50% could indicate a known negative effect from exposure. We found no significant association between a child having had documented imaging studies and awareness of long-term negative effects (P = 0.22). Participants preferred to learn more about this topic from an Internet-based resource (50%), informational pamphlet (38%), or via treating physician (33%). Parents and legal guardians are largely unaware that exposure to radiation during medical imaging carries an inherent risk for their child. Health care providers wishing to educate caregivers should utilize reliable Internet sources, educational pamphlets, and direct communication.

Health effects of oxygenated fuels.

PubMed Central

Costantini, M G

1993-01-01

The use of oxygenated fuels is anticipated to increase over the next decades. This paper reviews the toxicological and exposure information for methyl tertiary-butyl ether (MTBE), a fuel additive, and methanol, a replacement fuel, and discusses the possible health consequences of exposure of the general public to these compounds. For MTBE, the health effects information available is derived almost exclusively from rodent studies, and the exposure data are limited to a few measurements at some service stations. Based on these data, it appears unlikely that the normal population is at high risk of exposure to MTBE vapor. However, in the absence of health and pharmacokinetic data in humans or in nonhuman primates, this conclusion is not strongly supported. Similarly, there are a number of uncertainties to take into consideration in estimating human risk from the use of methanol as a fuel. Although methanol may be toxic to humans at concentrations that overwhelm certain enzymes involved in methanol metabolism, the data available provide little evidence to indicate that exposure to methanol vapors from the use of methanol as a motor vehicle fuel will result in adverse health effects. The uncertainties in this conclusion are based on the lack of information on dose-response relationship at reasonable, projected exposure levels and of studies examining end points of concern in sensitive species. In developing a quantitative risk assessment, more needs to be known about health effects in primates or humans and the range of exposure expected for the general public for both compounds. PMID:8020439

Biomarkers of environmental benzene exposure.

PubMed Central

Weisel, C; Yu, R; Roy, A; Georgopoulos, P

1996-01-01

Environmental exposures to benzene result in increases in body burden that are reflected in various biomarkers of exposure, including benzene in exhaled breath, benzene in blood and urinary trans-trans-muconic acid and S-phenylmercapturic acid. A review of the literature indicates that these biomarkers can be used to distinguish populations with different levels of exposure (such as smokers from nonsmokers and occupationally exposed from environmentally exposed populations) and to determine differences in metabolism. Biomarkers in humans have shown that the percentage of benzene metabolized by the ring-opening pathway is greater at environmental exposures than that at higher occupational exposures, a trend similar to that found in animal studies. This suggests that the dose-response curve is nonlinear; that potential different metabolic mechanisms exist at high and low doses; and that the validity of a linear extrapolation of adverse effects measured at high doses to a population exposed to lower, environmental levels of benzene is uncertain. Time-series measurements of the biomarker, exhaled breath, were used to evaluate a physiologically based pharmacokinetic (PBPK) model. Biases were identified between the PBPK model predictions and experimental data that were adequately described using an empirical compartmental model. It is suggested that a mapping of the PBPK model to a compartmental model can be done to optimize the parameters in the PBPK model to provide a future framework for developing a population physiologically based pharmacokinetic model. PMID:9118884

Clusters of community exposure to coastal flooding hazards based on storm and sea level rise scenarios—implications for adaptation networks in the San Francisco Bay region

USGS Publications Warehouse

Hummel, Michelle; Wood, Nathan J.; Schweikert, Amy; Stacey, Mark T.; Jones, Jeanne; Barnard, Patrick L.; Erikson, Li H.

2018-01-01

Sea level is projected to rise over the coming decades, further increasing the extent of flooding hazards in coastal communities. Efforts to address potential impacts from climate-driven coastal hazards have called for collaboration among communities to strengthen the application of best practices. However, communities currently lack practical tools for identifying potential partner communities based on similar hazard exposure characteristics. This study uses statistical cluster analysis to identify similarities in community exposure to flooding hazards for a suite of sea level rise and storm scenarios. We demonstrate this approach using 63 jurisdictions in the San Francisco Bay region of California (USA) and compare 21 distinct exposure variables related to residents, employees, and structures for six hazard scenario combinations of sea level rise and storms. Results indicate that cluster analysis can provide an effective mechanism for identifying community groupings. Cluster compositions changed based on the selected societal variables and sea level rise scenarios, suggesting that a community could participate in multiple networks to target specific issues or policy interventions. The proposed clustering approach can serve as a data-driven foundation to help communities identify other communities with similar adaptation challenges and to enhance regional efforts that aim to facilitate adaptation planning and investment prioritization.

Key risk indicators for accident assessment conditioned on pre-crash vehicle trajectory.

PubMed

Shi, X; Wong, Y D; Li, M Z F; Chai, C

2018-08-01

Accident events are generally unexpected and occur rarely. Pre-accident risk assessment by surrogate indicators is an effective way to identify risk levels and thus boost accident prediction. Herein, the concept of Key Risk Indicator (KRI) is proposed, which assesses risk exposures using hybrid indicators. Seven metrics are shortlisted as the basic indicators in KRI, with evaluation in terms of risk behaviour, risk avoidance, and risk margin. A typical real-world chain-collision accident and its antecedent (pre-crash) road traffic movements are retrieved from surveillance video footage, and a grid remapping method is proposed for data extraction and coordinates transformation. To investigate the feasibility of each indicator in risk assessment, a temporal-spatial case-control is designed. By comparison, Time Integrated Time-to-collision (TIT) performs better in identifying pre-accident risk conditions; while Crash Potential Index (CPI) is helpful in further picking out the severest ones (the near-accident). Based on TIT and CPI, the expressions of KRIs are developed, which enable us to evaluate risk severity with three levels, as well as the likelihood. KRI-based risk assessment also reveals predictive insights about a potential accident, including at-risk vehicles, locations and time. Furthermore, straightforward thresholds are defined flexibly in KRIs, since the impact of different threshold values is found not to be very critical. For better validation, another independent real-world accident sample is examined, and the two results are in close agreement. Hierarchical indicators such as KRIs offer new insights about pre-accident risk exposures, which is helpful for accident assessment and prediction. Copyright © 2018 Elsevier Ltd. All rights reserved.

Regulation of actions and habits by ventral hippocampal trkB and adolescent corticosteroid exposure

PubMed Central

Barfield, Elizabeth T.; Gerber, Kyle J.; Zimmermann, Kelsey S.; Ressler, Kerry J.; Parsons, Ryan G.

2017-01-01

In humans and rodents, stress promotes habit-based behaviors that can interfere with action–outcome decision-making. Further, developmental stressor exposure confers long-term habit biases across rodent–primate species. Despite these homologies, mechanisms remain unclear. We first report that exposure to the primary glucocorticoid corticosterone (CORT) in adolescent mice recapitulates multiple neurobehavioral consequences of stressor exposure, including long-lasting biases towards habit-based responding in a food-reinforced operant conditioning task. In both adolescents and adults, CORT also caused a shift in the balance between full-length tyrosine kinase receptor B (trkB) and a truncated form of this neurotrophin receptor, favoring the inactive form throughout multiple corticolimbic brain regions. In adolescents, phosphorylation of the trkB substrate extracellular signal-regulated kinase 42/44 (ERK42/44) in the ventral hippocampus was also diminished, a long-term effect that persisted for at least 12 wk. Administration of the trkB agonist 7,8-dihydroxyflavone (7,8-DHF) during adolescence at doses that stimulated ERK42/44 corrected long-lasting corticosterone-induced behavioral abnormalities. Meanwhile, viral-mediated overexpression of truncated trkB in the ventral hippocampus reduced local ERK42/44 phosphorylation and was sufficient to induce habit-based and depression-like behaviors. Together, our findings indicate that ventral hippocampal trkB is essential to goal-directed action selection, countering habit-based behavior otherwise facilitated by developmental stress hormone exposure. They also reveal an early-life sensitive period during which trkB–ERK42/44 tone determines long-term behavioral outcomes. PMID:29186135

Regulation of actions and habits by ventral hippocampal trkB and adolescent corticosteroid exposure.

PubMed

Barfield, Elizabeth T; Gerber, Kyle J; Zimmermann, Kelsey S; Ressler, Kerry J; Parsons, Ryan G; Gourley, Shannon L

2017-11-01

In humans and rodents, stress promotes habit-based behaviors that can interfere with action-outcome decision-making. Further, developmental stressor exposure confers long-term habit biases across rodent-primate species. Despite these homologies, mechanisms remain unclear. We first report that exposure to the primary glucocorticoid corticosterone (CORT) in adolescent mice recapitulates multiple neurobehavioral consequences of stressor exposure, including long-lasting biases towards habit-based responding in a food-reinforced operant conditioning task. In both adolescents and adults, CORT also caused a shift in the balance between full-length tyrosine kinase receptor B (trkB) and a truncated form of this neurotrophin receptor, favoring the inactive form throughout multiple corticolimbic brain regions. In adolescents, phosphorylation of the trkB substrate extracellular signal-regulated kinase 42/44 (ERK42/44) in the ventral hippocampus was also diminished, a long-term effect that persisted for at least 12 wk. Administration of the trkB agonist 7,8-dihydroxyflavone (7,8-DHF) during adolescence at doses that stimulated ERK42/44 corrected long-lasting corticosterone-induced behavioral abnormalities. Meanwhile, viral-mediated overexpression of truncated trkB in the ventral hippocampus reduced local ERK42/44 phosphorylation and was sufficient to induce habit-based and depression-like behaviors. Together, our findings indicate that ventral hippocampal trkB is essential to goal-directed action selection, countering habit-based behavior otherwise facilitated by developmental stress hormone exposure. They also reveal an early-life sensitive period during which trkB-ERK42/44 tone determines long-term behavioral outcomes.

Outdoor radiofrequency radiation levels in the West Bank-Palestine.

PubMed

Lahham, Adnan; Hammash, Alaa

2012-05-01

This work presents the results of exposure levels to radio frequency (RF) emission from different sources in the environment of the West Bank-Palestine. These RF emitters include FM and TV broadcasting stations and mobile phone base stations. Power densities were measured at 65 locations distributed over the West Bank area. These locations include mainly centres of the major cities. Also a 24 h activity level was investigated for a mobile phone base station to determine the maximum activity level for this kind of RF emitters. All measurements were conducted at a height of 1.7 m above ground level using hand held Narda SRM 3000 spectrum analyzer with isotropic antenna capable of collecting RF signals in the frequency band from 75 MHz to 3 GHz. The average value of power density resulted from FM radio broadcasting in all investigated locations was 0.148 μW cm(-2), from TV broadcasting was 0.007 μW cm(-2) and from mobile phone base station was 0.089 μW cm(-2). The maximum total exposure evaluated at any location was 3.86 μW cm(-2). The corresponding exposure quotient calculated for this site was 0.02. This value is well below unity indicating compliance with the International Commission on non-ionising Radiation protection guidelines. Contributions from all relevant RF sources to the total exposure were evaluated and found to be ~62 % from FM radio, 3 % for TV broadcasting and 35 % from mobile phone base stations. The average total exposure from all investigated RF sources was 0.37 μW cm(-2).

Modeling spatial patterns of link-based PM2.5 emissions and subsequent human exposure in a large canadian metropolitan area

NASA Astrophysics Data System (ADS)

Requia, Weeberb J.; Dalumpines, Ron; Adams, Matthew D.; Arain, Altaf; Ferguson, Mark; Koutrakis, Petros

2017-06-01

Understanding the relationship between mobile source emissions and subsequent human exposure is crucial for emissions control. Determining this relationship over space is fundamental to improve the accuracy and precision of public policies. In this study, we evaluated the spatial patterns of link-based PM2.5 emissions and subsequent human exposure in a large Canadian metropolitan area - the Greater Toronto and Hamilton Area (GTHA). This study was performed in three stages. First, we estimated vehicle emissions using transportation models and emission simulators. Then we evaluated human exposure to PM2.5 emissions using the Intake fraction (iF) approach. Finally, we applied geostatistical methods to assess spatial patterns of vehicle emissions and subsequent human exposure based on three prospective goals: i) classification of emissions (Global Moran's I test), ii) level of emission exposure (Getis-Ord General G test), and; iii) location of emissions (Anselin Local Moran's I). Our results showed that passenger vehicles accounted for the highest total amount of PM2.5 emissions, representing 57% emissions from all vehicles. Examining only the emissions from passenger vehicles, on average, each person in the GTHA inhales 2.58 × 10-3 ppm per day. Accounting the emissions from buses and trucks, on average each person inhales 0.12 × 10-3 and 1.91 × 10-3 ppm per day, respectively. For both PM2.5 emissions and human exposure using iF approach, our analysis showed Moran's Index greater than 0 for all vehicle categories, suggesting the presence of significant clusters (p-value <0.01) in the region. Our study indicates that air pollution control policy must be developed for the whole region, because of the spatial distribution of housing and businesses centers and inter-connectivity of transportation networks across the region, where a policy cannot simply be based on a municipal or other boundaries.

DEVELOPMENT OF MICROARRAYS AS A TOOL FOR DISCOVERING ENVIRONMENTAL EXPOSURE INDICATORS

EPA Science Inventory

Toxicogenomics includes research to identify differential gene expression in laboratory and field animals exposed to toxicants, and ultimately, to link the earliest indicators of exposure to adverse effects in organisms and populations. The USEPA National Exposure Research Labor...

Induction of reactive oxygen species in marine phytoplankton under crude oil exposure.

PubMed

Ozhan, Koray; Zahraeifard, Sara; Smith, Aaron P; Bargu, Sibel

2015-12-01

Exposure of phytoplankton to the water-accommodated fraction of crude oil can elicit a number of stress responses, but the mechanisms that drive these responses are unclear. South Louisiana crude oil was selected to investigate its effects on population growth, chlorophyll a (Chl a) content, antioxidative defense, and lipid peroxidation, for the marine diatom, Ditylum brightwellii, and the dinoflagellate, Heterocapsa triquetra, in laboratory-based microcosm experiments. The transcript levels of several possible stress-responsive genes in D. brightwellii were also measured. The microalgae were exposed to crude oil for up to 96 h, and Chl a content, superoxide dismutase (SOD), the glutathione pool (GSH and GSSG), and lipid peroxidation content were analyzed. The cell growth of both phytoplankton species was inhibited with increasing crude oil concentrations. Crude oil exposure did not affect Chl a content significantly in cells. SOD activities showed similar responses in both species, being enhanced at 4- and 8-mg/L crude oil exposure. Only H. triquetra demonstrated enhanced activity in GSSG pool and lipid peroxidation at 8-mg/L crude oil exposure, suggesting that phytoplankton species have distinct physiological responses and tolerance levels to crude oil exposure. This study indicated the activation of reactive oxygen species (ROS) in phytoplankton under crude oil exposure; however, the progressive damage in cells is still unknown. Thus, ROS-related damage in nucleic acid, lipids, proteins, and DNA, due to crude oil exposure could be a worthwhile subject of study to better understand crude oil toxicity at the base of the food web.

Multiplexed Activity-based Protein Profiling of the Human Pathogen Aspergillus fumigatus Reveals Large Functional Changes upon Exposure to Human Serum*

PubMed Central

Wiedner, Susan D.; Burnum, Kristin E.; Pederson, LeeAnna M.; Anderson, Lindsey N.; Fortuin, Suereta; Chauvigné-Hines, Lacie M.; Shukla, Anil K.; Ansong, Charles; Panisko, Ellen A.; Smith, Richard D.; Wright, Aaron T.

2012-01-01

Environmental adaptability is critical for survival of the fungal human pathogen Aspergillus fumigatus in the immunocompromised host lung. We hypothesized that exposure of the fungal pathogen to human serum would lead to significant alterations to the organism's physiology, including metabolic activity and stress response. Shifts in functional pathway and corresponding enzyme reactivity of A. fumigatus upon exposure to the human host may represent much needed prognostic indicators of fungal infection. To address this, we employed a multiplexed activity-based protein profiling (ABPP) approach coupled to quantitative mass spectrometry-based proteomics to measure broad enzyme reactivity of the fungus cultured with and without human serum. ABPP showed a shift from aerobic respiration to ethanol fermentation and utilization over time in the presence of human serum, which was not observed in serum-free culture. Our approach provides direct insight into this pathogen's ability to survive, adapt, and proliferate. Additionally, our multiplexed ABPP approach captured a broad swath of enzyme reactivity and functional pathways and provides a method for rapid assessment of the A. fumigatus response to external stimuli. PMID:22865858

Multiplexed activity-based protein profiling of the human pathogen Aspergillus fumigatus reveals large functional changes upon exposure to human serum.

PubMed

Wiedner, Susan D; Burnum, Kristin E; Pederson, LeeAnna M; Anderson, Lindsey N; Fortuin, Suereta; Chauvigné-Hines, Lacie M; Shukla, Anil K; Ansong, Charles; Panisko, Ellen A; Smith, Richard D; Wright, Aaron T

2012-09-28

Environmental adaptability is critical for survival of the fungal human pathogen Aspergillus fumigatus in the immunocompromised host lung. We hypothesized that exposure of the fungal pathogen to human serum would lead to significant alterations to the organism's physiology, including metabolic activity and stress response. Shifts in functional pathway and corresponding enzyme reactivity of A. fumigatus upon exposure to the human host may represent much needed prognostic indicators of fungal infection. To address this, we employed a multiplexed activity-based protein profiling (ABPP) approach coupled to quantitative mass spectrometry-based proteomics to measure broad enzyme reactivity of the fungus cultured with and without human serum. ABPP showed a shift from aerobic respiration to ethanol fermentation and utilization over time in the presence of human serum, which was not observed in serum-free culture. Our approach provides direct insight into this pathogen's ability to survive, adapt, and proliferate. Additionally, our multiplexed ABPP approach captured a broad swath of enzyme reactivity and functional pathways and provides a method for rapid assessment of the A. fumigatus response to external stimuli.

Equity monitoring for social marketing: use of wealth quintiles and the concentration index for decision making in HIV prevention, family planning, and malaria programs.

PubMed

Chakraborty, Nirali M; Firestone, Rebecca; Bellows, Nicole

2013-01-01

The majority of social marketing programs are intended to reach the poor. It is therefore essential that social marketing organizations monitor the health equity of their programs and improve targeting when the poor are not being reached. Current measurement approaches are often insufficient for decision making because they fail to show a program's ability to reach the poor and demonstrate progress over time. Further, effective program equity metrics should be benchmarked against a national reference population and consider exposure, not just health outcomes, to measure direct results of implementation. This study compares two measures of health equity, concentration indices and wealth quintiles, using a defined reference population, and considers benefits of both measures together to inform programmatic decision making. Three datasets from recent cross-sectional behavioral surveys on malaria, HIV, and family planning from Nepal and Burkina Faso were used to calculate concentration indices and wealth quintiles. Each sample was standardized to national wealth distributions based on recent Demographic and Health Surveys. Wealth quintiles were generated and concentration indices calculated for health outcomes and program exposure in each sample. Chi-square and t-tests were used to assess statistical significance of results. Reporting wealth quintiles showed that recipients of Population Services International (PSI) interventions were wealthier than national populations. Both measures indicated that desirable health outcomes were usually concentrated among wealthier populations. Positive and significant concentration indices in all three surveys indicated that wealth and program exposure were correlated; however this relationship was not necessarily linear. In analyzing the equity of modern contraceptive use stratified by exposure to family planning messages in Nepal, the outcome was equitable (concentration index = 0.006, p = 0.68) among the exposed, while the wealthy were more likely to use modern contraceptives (concentration index = 0.071, p < 0.01) among the unexposed. Using wealth quintiles and concentration indices together for equity monitoring improves usability of findings for decision making. Applying both metrics, and analyzing equity of exposure along with health outcomes, provides results that have statistical and programmatic significance. Benchmarking equity data against national data improves generalizability. This approach benefits social marketers and global health implementers to improve strategic decision making and programs' ability to reach the poor.

Equity monitoring for social marketing: use of wealth quintiles and the concentration index for decision making in HIV prevention, family planning, and malaria programs

PubMed Central

2013-01-01

Background The majority of social marketing programs are intended to reach the poor. It is therefore essential that social marketing organizations monitor the health equity of their programs and improve targeting when the poor are not being reached. Current measurement approaches are often insufficient for decision making because they fail to show a program's ability to reach the poor and demonstrate progress over time. Further, effective program equity metrics should be benchmarked against a national reference population and consider exposure, not just health outcomes, to measure direct results of implementation. This study compares two measures of health equity, concentration indices and wealth quintiles, using a defined reference population, and considers benefits of both measures together to inform programmatic decision making. Methods Three datasets from recent cross-sectional behavioral surveys on malaria, HIV, and family planning from Nepal and Burkina Faso were used to calculate concentration indices and wealth quintiles. Each sample was standardized to national wealth distributions based on recent Demographic and Health Surveys. Wealth quintiles were generated and concentration indices calculated for health outcomes and program exposure in each sample. Chi-square and t-tests were used to assess statistical significance of results. Results Reporting wealth quintiles showed that recipients of Population Services International (PSI) interventions were wealthier than national populations. Both measures indicated that desirable health outcomes were usually concentrated among wealthier populations. Positive and significant concentration indices in all three surveys indicated that wealth and program exposure were correlated; however this relationship was not necessarily linear. In analyzing the equity of modern contraceptive use stratified by exposure to family planning messages in Nepal, the outcome was equitable (concentration index = 0.006, p = 0.68) among the exposed, while the wealthy were more likely to use modern contraceptives (concentration index = 0.071, p < 0.01) among the unexposed. Conclusions Using wealth quintiles and concentration indices together for equity monitoring improves usability of findings for decision making. Applying both metrics, and analyzing equity of exposure along with health outcomes, provides results that have statistical and programmatic significance. Benchmarking equity data against national data improves generalizability. This approach benefits social marketers and global health implementers to improve strategic decision making and programs' ability to reach the poor. PMID:23902715

Effective formation method for an aspherical microlens array based on an aperiodic moving mask during exposure.

PubMed

Shi, Lifang; Du, Chunlei; Dong, Xiaochun; Deng, Qiling; Luo, Xiangang

2007-12-01

An aperiodic mask design method for fabricating a microlens array with an aspherical profile is proposed. The nonlinear relationship between exposure doses and lens profile is considered, and the select criteria of quantization interval and fabrication range of the method are given. The mask function of a quadrangle microlens array with a hyperboloid profile used in the infrared was constructed by using this method. The microlens array can be effectively fabricated during a one time exposure process using the mask. Reactive ion etching was carried out to transfer the structure into the substrate of germanium. The measurement results indicate that the roughness is less than 10 nm (pv), and the profile error is less than 40 nm (rms).

Reaction of the immune system to low-level RF/MW exposures.

PubMed

Szmigielski, Stanislaw

2013-06-01

Radiofrequency (RF) and microwave (MW) radiation have been used in the modern world for many years. The rapidly increasing use of cellular phones in recent years has seen increased interest in relation to the possible health effects of exposure to RF/MW radiation. In 2011 a group of international experts organized by the IARC (International Agency for Research on Cancer in Lyon) concluded that RF/MW radiations should be listed as a possible carcinogen (group 2B) for humans. The incomplete knowledge of RF/MW-related cancer risks has initiated searches for biological indicators sensitive enough to measure the "weak biological influence" of RF/MWs. One of the main candidates is the immune system, which is able to react in a measurable way to discrete environmental stimuli. In this review, the impacts of weak RF/MW fields, including cell phone radiation, on various immune functions, both in vitro and in vivo, are discussed. The bulk of available evidence clearly indicates that various shifts in the number and/or activity of immunocompetent cells are possible, however the results are inconsistent. For example, a number of lymphocyte functions have been found to be enhanced and weakened within single experiments based on exposure to similar intensities of MW radiation. Certain premises exist which indicate that, in general, short-term exposure to weak MW radiation may temporarily stimulate certain humoral or cellular immune functions, while prolonged irradiation inhibits the same functions. Copyright © 2013. Published by Elsevier B.V.

Biomarker analysis of hemoglobin adducts of acrylamide and glycidamide enantiomers for mid-term internal exposure assessment by isotope dilution ultra-high performance liquid chromatography tandem mass spectrometry.

PubMed

Zhang, Yu; Wang, Qiao; Zhang, Gong; Jia, Wei; Ren, Yiping; Wu, Yongning

2018-02-01

Hemoglobin (Hb) adducts of acrylamide (AA) and its oxidative metabolite glycidamide (GA) are important biomarkers for evaluating the mid-term exposure of acrylamide toxicity in vivo. Taking pentafluoro-2-methylphenyl isothiocyanates of N-(2-carbamoylethyl)valine (AAVal-PFPTH) and N-(2-carbamoyl-2-hydroxyethy)valine (GAVal-PFPTH) as target analytes, we developed an isotope dilution ultra-high performance liquid chromatograph tandem mass spectrometry (UHPLC-MS/MS) method for the simultaneous determination of AA and GA hemoglobin (Hb) adducts under the electroscopy ionization negative (ESI‾) mode in the present work. Among them, the enantiomer pair of GA-Hb adducts was firstly identified and successfully separated at baseline level. The method achieved high sensitivity with the LOD and LOQ ranging 1.43-5.05pmol/g Hb and 4.78-16.82pmol/g Hb, respectively. The recovery rates with low, intermediate and high spiking levels were calculated as 97.0-105.2%, 97.4-106.4% and 100.3-111.2%, respectively. Acceptable within-laboratory reproducibility (RSD < 13.7%) substantially supported the robustness of current UHPLC-MS/MS method, which was successfully applied to measure the hemoglobin adducts of acrylamide and glycidamide enantiomers in blood of both rats and humans. A linear exposure assessment model was developed for estimating the daily exposure to acrylamide in humans via considering acrylamide hemoglobin adducts as variables, indicating a novel connect between biomarker-based internal exposure and dietary-based external exposure. Overall, the present instrumental analysis and related internal exposure assessment model provide a substantially methodological support for profiling the internal biological exposure and estimating the external dietary exposure to acrylamide. Copyright © 2017 Elsevier B.V. All rights reserved.

Rural Villagers and Urban Residents Exposure to Poultry in China

PubMed Central

Shi, Ying; Liao, Qiaohong; Zhou, Hang; Zhou, Lei; Li, Leilei; Wu, Jiabing; Zhang, Shunxiang; Yu, Zhangda; Wu, Xiaomin; Ma, Hanwu; Lu, Jianhua; Cowling, Benjamin J.; Yu, Hongjie

2014-01-01

Patterns of poultry exposure in rural and urban areas in China have not been systematically evaluated and compared. The objective of our study is to investigate patterns in human exposure to poultry in rural and urban China. We conducted a two-stage household-based clustered survey on population exposure to live/sick/dead poultry in Xiuning and Shenzhen. Half of the rural households (51%) in Xiuning raised poultry, mostly (78%) free-range. Around half of those households (40%) allowed poultry to stay in their living areas. One quarter of villagers reported having contact with sick or dead poultry. In Shenzhen, 37% urban residents visited live poultry markets. Among these, 40% purchased live poultry and 16% touched the poultry or cages during purchase. Our findings indicated that human exposure to poultry was different in rural and urban areas in China. This discrepancy could contribute to the observed differences in epidemiologic characteristics between urban and rural cases of influenza A(H7N9) and A(H5N1) virus infection. PMID:24769673

Trimethoprim use in early pregnancy and the risk of miscarriage: a register-based nationwide cohort study.

PubMed

Andersen, J T; Petersen, M; Jimenez-Solem, E; Broedbaek, K; Andersen, E W; Andersen, N L; Afzal, S; Torp-Pedersen, C; Keiding, N; Poulsen, H E

2013-08-01

The antibiotic trimethoprim acts as a folate antagonist. Since trophoblasts are very sensitive to drugs that interfere with the folic acid cycle and thereby inhibit DNA synthesis, use of trimethoprim during the first trimester could be associated with miscarriage. A nationwide cohort study including all women in Denmark with a registered pregnancy between 1997 and 2005 was conducted. We used nationwide registers to identify all women giving birth, having a record of miscarriage or induced abortion. Data on exposure to trimethoprim were obtained from the National Prescription Register. Cox proportional hazard regression analysis with exposure to trimethoprim as a time-dependent variable was used to estimate the risk of miscarriage. The adjusted hazard ratio of having a miscarriage after exposure to trimethoprim in the first trimester compared to non-exposure was 2∙04 (95% confidence interval 1∙43-2∙91). Our results indicate that trimethoprim exposure in the first trimester is associated with a doubling of the hazard of miscarriage.

Space radiation and cardiovascular disease risk

PubMed Central

Boerma, Marjan; Nelson, Gregory A; Sridharan, Vijayalakshmi; Mao, Xiao-Wen; Koturbash, Igor; Hauer-Jensen, Martin

2015-01-01

Future long-distance space missions will be associated with significant exposures to ionizing radiation, and the health risks of these radiation exposures during manned missions need to be assessed. Recent Earth-based epidemiological studies in survivors of atomic bombs and after occupational and medical low dose radiation exposures have indicated that the cardiovascular system may be more sensitive to ionizing radiation than was previously thought. This has raised the concern of a cardiovascular disease risk from exposure to space radiation during long-distance space travel. Ground-based studies with animal and cell culture models play an important role in estimating health risks from space radiation exposure. Charged particle space radiation has dense ionization characteristics and may induce unique biological responses, appropriate simulation of the space radiation environment and careful consideration of the choice of the experimental model are critical. Recent studies have addressed cardiovascular effects of space radiation using such models and provided first results that aid in estimating cardiovascular disease risk, and several other studies are ongoing. Moreover, astronauts could potentially be administered pharmacological countermeasures against adverse effects of space radiation, and research is focused on the development of such compounds. Because the cardiovascular response to space radiation has not yet been clearly defined, the identification of potential pharmacological countermeasures against cardiovascular effects is still in its infancy. PMID:26730293

Effects of vehicle-ride exposure on cervical pathology: a meta-analysis

PubMed Central

KOLLOCK, Roger; GAMES, Kenneth; WILSON, Alan E.; SEFTON, JoEllen M.

2015-01-01

Research to date on the effect vehicle-ride exposure has on the development of cervical pathologies in mounted Warfighters is conflicting. The purpose of this study was to determine if the literature suggests a definite effect of vehicle-ride exposure on cervical pathology. Databases were searched using multiple combinations of select terms. Twelve studies meeting the inclusion criteria were included in the meta-analysis. The results of the meta-analysis revealed that overall vehicle-ride exposure was likely to increase cervical pathology (p=0.01, odds ratio=1.59, 95% CI=1.16−2.17). Using vehicle type as a moderator it was found that vehicle-ride exposure in ground-based vehicles (p=0.01, odds ratio=2.33, 95% CI=1.41−3.85) and fixed-wing aircraft (p=0.01, odds ratio =1.59, 95% CI=1.13−2.23) were likely to increase cervical pathology. Using operator/other personnel moderator it was found that in the populations tested, fighter pilots or fighter jet weapons systems operators were more likely to develop a cervical pathology (p<0.001, odds ratio=1.78, 95% CI=1.26−2.50). The available studies indicate an increase in cervical pathology for personnel exposed to ground-based vehicles and fixed-wing aircraft. PMID:25739897

International and National Expert Group Evaluations: Biological/Health Effects of Radiofrequency Fields

PubMed Central

Vijayalaxmi; Scarfi, Maria R.

2014-01-01

The escalated use of various wireless communication devices, which emit non-ionizing radiofrequency (RF) fields, have raised concerns among the general public regarding the potential adverse effects on human health. During the last six decades, researchers have used different parameters to investigate the effects of in vitro and in vivo exposures of animals and humans or their cells to RF fields. Data reported in peer-reviewed scientific publications were contradictory: some indicated effects while others did not. International organizations have considered all of these data as well as the observations reported in human epidemiological investigations to set-up the guidelines or standards (based on the quality of published studies and the “weight of scientific evidence” approach) for RF exposures in occupationally exposed individuals and the general public. Scientists with relevant expertise in various countries have also considered the published data to provide the required scientific information for policy-makers to develop and disseminate authoritative health information to the general public regarding RF exposures. This paper is a compilation of the conclusions, on the biological effects of RF exposures, from various national and international expert groups, based on their analyses. In general, the expert groups suggested a reduction in exposure levels, precautionary approach, and further research. PMID:25211777

Space radiation and cardiovascular disease risk.

PubMed

Boerma, Marjan; Nelson, Gregory A; Sridharan, Vijayalakshmi; Mao, Xiao-Wen; Koturbash, Igor; Hauer-Jensen, Martin

2015-12-26

Future long-distance space missions will be associated with significant exposures to ionizing radiation, and the health risks of these radiation exposures during manned missions need to be assessed. Recent Earth-based epidemiological studies in survivors of atomic bombs and after occupational and medical low dose radiation exposures have indicated that the cardiovascular system may be more sensitive to ionizing radiation than was previously thought. This has raised the concern of a cardiovascular disease risk from exposure to space radiation during long-distance space travel. Ground-based studies with animal and cell culture models play an important role in estimating health risks from space radiation exposure. Charged particle space radiation has dense ionization characteristics and may induce unique biological responses, appropriate simulation of the space radiation environment and careful consideration of the choice of the experimental model are critical. Recent studies have addressed cardiovascular effects of space radiation using such models and provided first results that aid in estimating cardiovascular disease risk, and several other studies are ongoing. Moreover, astronauts could potentially be administered pharmacological countermeasures against adverse effects of space radiation, and research is focused on the development of such compounds. Because the cardiovascular response to space radiation has not yet been clearly defined, the identification of potential pharmacological countermeasures against cardiovascular effects is still in its infancy.

Social stressors and air pollution across New York City communities: a spatial approach for assessing correlations among multiple exposures.

PubMed

Shmool, Jessie L C; Kubzansky, Laura D; Newman, Ogonnaya Dotson; Spengler, John; Shepard, Peggy; Clougherty, Jane E

2014-11-06

Recent toxicological and epidemiological evidence suggests that chronic psychosocial stress may modify pollution effects on health. Thus, there is increasing interest in refined methods for assessing and incorporating non-chemical exposures, including social stressors, into environmental health research, towards identifying whether and how psychosocial stress interacts with chemical exposures to influence health and health disparities. We present a flexible, GIS-based approach for examining spatial patterns within and among a range of social stressors, and their spatial relationships with air pollution, across New York City, towards understanding their combined effects on health. We identified a wide suite of administrative indicators of community-level social stressors (2008-2010), and applied simultaneous autoregressive models and factor analysis to characterize spatial correlations among social stressors, and between social stressors and air pollutants, using New York City Community Air Survey (NYCCAS) data (2008-2009). Finally, we provide an exploratory ecologic analysis evaluating possible modification of the relationship between nitrogen dioxide (NO2) and childhood asthma Emergency Department (ED) visit rates by social stressors, to demonstrate how the methods used to assess stressor exposure (and/or consequent psychosocial stress) may alter model results. Administrative indicators of a range of social stressors (e.g., high crime rate, residential crowding rate) were not consistently correlated (rho = - 0.44 to 0.89), nor were they consistently correlated with indicators of socioeconomic position (rho = - 0.54 to 0.89). Factor analysis using 26 stressor indicators suggested geographically distinct patterns of social stressors, characterized by three factors: violent crime and physical disorder, crowding and poor access to resources, and noise disruption and property crimes. In an exploratory ecologic analysis, these factors were differentially associated with area-average NO2 and childhood asthma ED visits. For example, only the 'violent crime and disorder' factor was significantly associated with asthma ED visits, and only the 'crowding and resource access' factor modified the association between area-level NO2 and asthma ED visits. This spatial approach enabled quantification of complex spatial patterning and confounding between chemical and non-chemical exposures, and can inform study design for epidemiological studies of separate and combined effects of multiple urban exposures.

The 737 graphite composite flight spoiler flight service evaluation

NASA Technical Reports Server (NTRS)

Stoecklin, R. L.

1977-01-01

The flight service experience of 110 graphite epoxy spoilers on 737 transport aircraft was reviewed as well as ground based environmental exposure of graphite epoxy material specimens for the period from April 1976 through April 1977. Several spoilers were installed on each of 27 aircraft representing seven major airlines operating throughout the world. A flight service evaluation program of at least 5 years is under way. As of April 30, 1977, a total of 766,938 spoiler flight hours and 1,168,090 spoiler landings were accumulated by the fleet. Based on visual ultrasonic, and destructive testing, there was no evidence of moisture migration into the honeycomb core and no core corrosion. Tests of removed spoilers and of ground based exposure specimens after the third year of service continue to indicate modest changes in composite strength properties.

Extraction and analysis of fumonisins and compounds indicative of fumonisin exposure in plant and mammalian tissues and cultured cells.

PubMed

Zitomer, Nicholas C; Riley, Ronald T

2011-01-01

Fumonisin mycotoxins are common contaminants in many grains, often at very low levels. Maize is -particularly problematic as one of the organisms that commonly produce fumonisins, the fungus Fusarium verticillioides, often exists as an endophyte of maize. Fumonisin is a potent inhibitor of the enzyme ceramide synthase, and this inhibition results in the accumulation of a variety of upstream compounds, most notably, the sphingoid bases sphingosine, sphinganine, 1-deoxysphinganine and, in plants, phytosphingosine. Fumonisin exposure results in a wide variety of species, sex, and strain-specific responses. This method provides a relatively fast means of extracting fumonisins, sphingoid bases, and sphingoid base 1-phosphates from tissues and cells, as well as the subsequent analyses and quantification of these compounds using liquid chromatography/tandem mass spectrometry.

GENE EXPRESSION PROFILING PROVIDES A SENSITIVE MEASURE OF EXPOSURE TO 17-A ETHINYLESTRADIOL IN THE FATHEAD MINNOW, PIMEPHALES PROMELAS

EPA Science Inventory

The freshwater fish, the fathead minnow (Pimephales promelas) represents an outstanding biological indicator response model organism based on its ubiquitous North American distribution and extensive use in acute and chronic testing of contaminants, effluents and receiving waters....

Introduction to Community-Focused Exposure and Risk Screening Tool (C-FERST)

EPA Science Inventory

C-FERST is a web-based “toolkit” of information, with community maps that show environmental data, public health data, and socioeconomic indications. It is used as a guide to help community assessments. With C-FERST you can: View maps of your community • Compare...

Development and application of traffic density-based parameters for studying near-road air pollutant exposure

EPA Science Inventory

Increasingly human populations are living and/or working in close proximity to heavily travelled roadways. There is a growing body of research indicating a variety of health conditions are adversely affected by near-road air pollutants. To reliably estimate the health risk assoc...

Development and application of traffic density-based Parameters for near-road air pollutant exposure

EPA Science Inventory

Increasingly human populations are living and/or working in close proximity to heavily travelled roadways. There is a growing body of research indicating a variety of health conditions are adversely affected by near-road air pollutants. To reliably estimate the health risk assoc...

Do We Need to Design Course-Based Undergraduate Research Experiences for Authenticity?

ERIC Educational Resources Information Center

Rowland, Susan; Pedwell, Rhianna; Lawrie, Gwen; Lovie-Toon, Joseph; Hung, Yu

2016-01-01

The recent push for more authentic teaching and learning in science, technology, engineering, and mathematics indicates a shared agreement that undergraduates require greater exposure to professional practices. There is considerable variation, however, in how "authentic" science education is defined. In this paper we present our…

Predicting E. Coli and Enterococci Concentrations in the South Fork Broad River Watershed Using Virtual Beach

EPA Science Inventory

Virtual Beach (VB) is a decision support tool that constructs site-specific statistical models to predict fecal indicator bacteria (FIB) at locations of exposure. Although primarily designed for making decisions regarding beach closures or issuance of swimming advisories based on...

DETECTING CCL-RELATED, EMERGING WATERBORNE HUMAN VIRUSES AND VIRAL INDICATORS FOR EXPOSURE ASSESSMENT

EPA Science Inventory

Enteric viruses cause waterborne disease outbreaks in the U.S. and worldwide. The primary focus of this task is to develop methods to measure the occurrence of enteric viruses in environmental and drinking waters. Cell culture- and molecular-based methods are being developed fo...

Measurement systems and indices of miners' exposure to radon daughter products in the air of mines.

PubMed

Domański, T

1990-01-01

This paper presents the classification of measurement systems that may be used for the assessment of miners' exposure to radiation in mines. The following systems were described and characterized as the Air Sampling System (ASS), the Environmental Control System (ECS), the Individual Dosimetry System (IDS), the Stream Monitoring System (SMS) and the Exhaust Monitoring System (EMS). The indices for evaluation of miners' working environments, or for assessment of individual or collective miners' exposure, were selected and determined. These are: average expected concentration (CAE), average observed concentration (CAO), average expected rate of exposure cumulation rate (EEXP), average observed exposure cumulation rate (EOBS), average effective exposure cumulation rate (EEFF). Mathematical formulae for determining all these indicators, according to the type of measurement system used in particular mines, are presented. The reliability of assessment of miners' exposure in particular measurement systems, as well as the role of the possible reference system, are discussed.

Acrylamide in commercial foods and intake by infants in Estonia.

PubMed

Elias, Andres; Roasto, Mati; Reinik, Mari; Nelis, Keiu; Nurk, Eha; Elias, Terje

2017-11-01

Acrylamide is formed when certain foods with low moisture are prepared at above 120 ºC, especially those foods containing asparagine and reducing sugars such as glucose and fructose. Acrylamide is a probable carcinogen, and from animal evidence the margins of exposure indicate a concern for neoplastic effects. On a body weight basis infants´ acrylamide intakes are often higher than those of adults. The aim of the study was to determine acrylamide levels in different commercially-available foods and to assess dietary acrylamide intakes by infants. The acrylamide content in samples ranged widely, from

Anthropometric factors and cutaneous melanoma: Prospective data from the population-based Janus Cohort.

PubMed

Stenehjem, Jo S; Veierød, Marit B; Nilsen, Lill Tove; Ghiasvand, Reza; Johnsen, Bjørn; Grimsrud, Tom K; Babigumira, Ronnie; Rees, Judith R; Robsahm, Trude E

2018-02-15

The aim of the present study was to prospectively examine risk of cutaneous melanoma (CM) according to measured anthropometric factors, adjusted for exposure to ultraviolet radiation (UVR), in a large population-based cohort in Norway. The Janus Cohort, including 292,851 Norwegians recruited 1972-2003, was linked to the Cancer Registry of Norway and followed for CM through 2014. Cox regression was used to estimate hazard ratios (HRs) of CM with 95% confidence intervals (CIs). Restricted cubic splines were incorporated into the Cox models to assess possible non-linear relationships. All analyses were adjusted for attained age, indicators of UVR exposure, education, and smoking status. During a mean follow-up of 27 years, 3,000 incident CM cases were identified. In men, CM risk was positively associated with body mass index, body surface area (BSA), height and weight (all p trends  < 0.001), and the exposure-response curves indicated an exponential increase in risk for all anthropometric factors. Weight loss of more than 2 kg in men was associated with a 53% lower risk (HR 0.47, 95% CI: 0.39, 0.57). In women, CM risk increased with increasing BSA (p trend  = 0.002) and height (p trend  < 0.001). The shape of the height-CM risk curve indicated an exponential increase. Our study suggests that large body size, in general, is a CM risk factor in men, and is the first to report that weight loss may reduce the risk of CM among men. © 2017 UICC.

Using Community-Based Participatory Research to Explore Backyard Gardening Practices and Soil Lead Concentrations in Urban Neighborhoods.

PubMed

Johnson, Sheri; Cardona, Dalila; Davis, Jeremy; Gramling, Benjamin; Hamilton, Chelsea; Hoffmann, Ray; Ruis, Sabrina; Soldat, Doug; Ventura, Steve; Yan, Ke

2016-01-01

Lead exposure is a serious health threat for children. Soil is an important exposure pathway, primarily through ingestion and inhalation. Urban agriculture is increasing. Potential environmental health risks associated with residential gardening may not be well known to community residents. A community-based participatory research (CBPR) approach was implemented to explore the relationship between urban residential vegetable gardening and lead exposure in children. The primary objectives were to characterize local backyard vegetable gardening practices, measure residential and commercial soil lead concentrations and spatial distributions, and identify priorities for individual and collective action. Participants were recruited in two stages. In phase 1, adult gardeners participated in structured interviews. In phase 2, a multistage representative sampling approach was implemented to recruit adult gardeners for interviews and soil testing. Twenty adults participated in gardening practice interviews. Adults perceive many benefits from backyard gardening and initially expressed few concerns about lead exposure risk. Results indicate that children are actively involved in backyard gardening. Total soil lead concentrations from 17 residential properties ranged from 7 to 3,234 mg kg-1(median, 187; mean, 432). Commercial soils had lead concentrations that ranged from 6 to 13 mg kg(-1) (median, 6.5; mean, 7.6). Nonparametric Mann-Whitney comparisons indicated a significant difference in lead concentration between commercial soil and residential soil (p<0.0001). Advocacy for resources needed to eliminate dangerous levels of lead from the environment, especially in communities where divestment has occurred, is enhanced through CBPR. Increasing access to soil testing is an important action step.

Testicular Development in Male Rats Is Sensitive to a Soy-Based Diet in the Neonatal Period1

PubMed Central

Napier, India D.; Simon, Liz; Perry, Devin; Cooke, Paul S.; Stocco, Douglas M.; Sepehr, Estatira; Doerge, Daniel R.; Kemppainen, Barbara W.; Morrison, Edward E.; Akingbemi, Benson T.

2014-01-01

ABSTRACT Approximately 30% of infants in the United States are exposed to high doses of isoflavones resulting from soy infant formula consumption. Soybeans contain the isoflavones genistin and daidzin, which are hydrolyzed in the gastrointestinal tract to their genistein and daidzein aglycones. Both aglycones possess hormonal activity and may interfere with male reproductive development. Testosterone, which supports male fertility, is mainly produced by testicular Leydig cells. Our previous studies indicated that perinatal exposure of male rats to isoflavones induced proliferative activity in Leydig cells and increased testosterone concentrations into adulthood. However, the relevance of the neonatal period as part of the perinatal window of isoflavone exposure remains to be established. The present study examined the effects of exposure to isoflavones on male offspring of dams maintained on a casein-based control or whole soybean diet in the neonatal period, that is, Days 2 to 21 postpartum. The results showed that the soybean diet stimulated proliferative activity in developing Leydig cells while suppressing their steroidogenic capacity in adulthood. In addition, isoflavone exposure decreased production of anti-Müllerian hormone by Sertoli cells. Similar to our previous in vitro studies of genistein action in Leydig cells, daidzein induced proliferation and interfered with signaling pathways to suppress steroidogenic activity. Overall, the data showed that the neonatal period is a sensitive window of exposure to isoflavones and support the view that both genistein and daidzein are responsible for biological effects associated with soy-based diets. PMID:24451983

Low-level exposure to air pollution and risk of adverse birth outcomes in Hillsborough County, Florida.

PubMed

Mainolfi, Maria B; Salihu, Hamisu M; Wilson, Roneé E; Mbah, Alfred K

2013-05-01

In this retrospective cohort (1998 to 2007), 145,445 singleton live births in Hillsborough, Florida, were analyzed to elucidate the relationship between fetal morbidity and prenatal exposure to six criteria air pollutants. This study was based on three linked databases: Florida Hospital Discharge, vital statistics records, and air pollution meteorological data from the Environmental Protection Agency. The primary outcomes of interest were low birth weight, preterm births, and small for gestational age. This study used structural equation modeling and trimester groupings to evaluate the relationship between air pollution and birth outcomes of pregnant residents. The latent variables of structural equation modeling yielded a significant B value of 0.35, indicating that exposure to the criteria pollutants in pregnancy may have a significant relationship to fetal morbidity. Exposure to criteria air pollutants in pregnancy is associated with fetal morbidity outcomes.

Psychosocial Health Status of Persons Seeking Treatment for Exposure to Libby Amphibole Asbestos

PubMed Central

Weinert, Clarann; Hill, Wade G.; Winters, Charlene A.; Kuntz, Sandra W.; Rowse, Kimberly; Hernandez, Tanis; Black, Brad; Cudney, Shirley

2011-01-01

A cross-sectional exploratory study was conducted to describe the psychosocial health status of persons seeking health care for exposure to Libby amphibole asbestos (LAA). Health indicators including depression, stress, acceptance of illness, and satisfaction with access and financial aspects of care were obtained via electronic and paper-pencil survey. The exposure pathway and demographic data were gleaned from the health record. Of the 386 participants, more than one-third (34.5%) demonstrated significant levels of psychological distress. The oldest group of women had the lowest levels of depression and stress and the highest acceptance of illness. Gender, age, and satisfaction with financial resources were significantly related to depression, stress, and acceptance of illness. Satisfaction with access to care was significant only for stress. No differences in depression, stress, and acceptance of illness were found based on residence, exposure pathway, or insurance status. PMID:22007326

Development and testing of an antitobacco school-based curriculum for deaf and hard of hearing youth.

PubMed

Berman, Barbara A; Guthmann, Debra S; Crespi, Catherine M; Liu, Weiqing

2011-01-01

A tobacco use prevention curriculum tailored for deaf/hard of hearing youth was tested using a quasi-experimental design. Two schools for the deaf received the curriculum; two served as noncurriculum controls. Surveys assessed changes in tobacco use, tobacco education exposure, and tobacco-related attitudes and knowledge among students in grades 7-12 over 3 school years (n = 511-616). Current (past month) smoking decreased significantly at one intervention school (23% to 8%,p = .007), and current smokeless tobacco use at the other (7.5% to 2.5%, p = .03). Tobacco education exposure and antitobacco attitudes and knowledge increased significantly at one or both intervention schools. At one control school, reported tobacco education exposure decreased (p < .001) and antitobacco attitudes increased (p = .01). The results indicate that the curriculum increased perceived tobacco education exposure and significantly affected tobacco-related practices, attitudes, and knowledge.

Childhood adversity, adult socioeconomic status and risk of work disability: a prospective cohort study.

PubMed

Halonen, Jaana I; Kivimäki, Mika; Vahtera, Jussi; Pentti, Jaana; Virtanen, Marianna; Ervasti, Jenni; Oksanen, Tuula; Lallukka, Tea

2017-09-01

To examine the combined effects of childhood adversities and low adult socioeconomic status (SES) on the risk of future work disability. Included were 34 384 employed Finnish Public Sector study participants who responded to questions about childhood adversities (none vs any adversity, eg, parental divorce or financial difficulties) in 2008, and whose adult SES in 2008 was available. We categorised exposure into four groups: neither (reference), childhood adversity only, low SES only or both. Participants were followed from 2009 until the first period of register-based work disability (sickness absence >9 days or disability pension) due to any cause, musculoskeletal or mental disorders; retirement; death or end of follow-up (December 2011). We ran Cox proportional hazard models adjusted for behavioural, health-related and work-related covariates, and calculated synergy indices for the combined effects. When compared with those with neither exposure, HR for work disability from any cause was increased among participants with childhood adversity, with low SES, and those with both exposures. The highest hazard was observed in those with both exposures: HR 2.53, 95% CI 2.29 to 2.79 for musculoskeletal disability, 1.55, 95% CI 1.36 to 1.78 for disability due to mental disorders and 1.29, 95% CI 1.20 to 1.39 for disability due to other reasons. The synergy indices did not indicate synergistic effects. These findings indicate that childhood psychosocial adversity and low adult SES are additive risk factors for work disability. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Swimmer illness associated with marine water exposure and water quality indicators: impact of widely used assumptions

EPA Science Inventory

Studies of health risks associated with recreational water exposure require investigators to make choices about water quality indicator averaging techniques, exposure definitions, follow-up periods, and model specifications; but, investigators seldom describe the impact of these ...

Evaluation of the COSHH Essentials Model with a Mixture of Organic Chemicals at a Medium-Sized Paint Producer

PubMed Central

Lee, Eun Gyung; Slaven, James; Bowen, Russell B.; Harper, Martin

2011-01-01

The Control of Substances Hazardous to Health (COSHH) Essentials model was evaluated using full-shift exposure measurements of five chemical components in a mixture [acetone, ethylbenzene, methyl ethyl ketone, toluene, and xylenes] at a medium-sized plant producing paint materials. Two tasks, batch-making and bucket-washing, were examined. Varying levels of control were already established in both tasks and the average exposures of individual chemicals were considerably lower than the regulatory and advisory 8-h standards. The average exposure fractions using the additive mixture formula were also less than unity (batch-making: 0.25, bucket-washing: 0.56) indicating the mixture of chemicals did not exceed the combined occupational exposure limit (OEL). The paper version of the COSHH Essentials model was used to calculate a predicted exposure range (PER) for each chemical according to different levels of control. The estimated PERs of the tested chemicals for both tasks did not show consistent agreement with exposure measurements when the comparison was made for each control method and this is believed to be because of the considerably different volatilities of the chemicals. Given the combination of health hazard and exposure potential components, the COSHH Essentials model recommended a control approach ‘special advice’ for both tasks, based on the potential reproductive hazard ascribed to toluene. This would not have been the same conclusion if some other chemical had been substituted (for example styrene, which has the same threshold limit value as toluene). Nevertheless, it was special advice, which had led to the combination of hygienic procedures in place at this plant. The probability of the combined exposure fractions exceeding unity was 0.0002 for the batch-making task indicating that the employees performing this task were most likely well protected below the OELs. Although the employees involved in the bucket-washing task had greater potential to exceed the threshold limit value of the mixture (P > 1 = 0.2375), the expected personal exposure after adjusting for the assigned protection factor for the respirators in use would be considerably lower (P > 1 = 0.0161). Thus, our findings suggested that the COSHH essentials model worked reasonably well for the volatile organic chemicals at the plant. However, it was difficult to override the reproductive hazard even though it was meant to be possible in principle. Further, it became apparent that an input of existing controls, which is not possible in the web-based model, may have allowed the model be more widely applicable. The experience of using the web-based COSHH Essentials model generated some suggestions to provide a more user-friendly tool to the model users who do not have expertise in occupational hygiene. PMID:21047985

Evaluation of the COSHH Essentials model with a mixture of organic chemicals at a medium-sized paint producer.

PubMed

Lee, Eun Gyung; Slaven, James; Bowen, Russell B; Harper, Martin

2011-01-01

The Control of Substances Hazardous to Health (COSHH) Essentials model was evaluated using full-shift exposure measurements of five chemical components in a mixture [acetone, ethylbenzene, methyl ethyl ketone, toluene, and xylenes] at a medium-sized plant producing paint materials. Two tasks, batch-making and bucket-washing, were examined. Varying levels of control were already established in both tasks and the average exposures of individual chemicals were considerably lower than the regulatory and advisory 8-h standards. The average exposure fractions using the additive mixture formula were also less than unity (batch-making: 0.25, bucket-washing: 0.56) indicating the mixture of chemicals did not exceed the combined occupational exposure limit (OEL). The paper version of the COSHH Essentials model was used to calculate a predicted exposure range (PER) for each chemical according to different levels of control. The estimated PERs of the tested chemicals for both tasks did not show consistent agreement with exposure measurements when the comparison was made for each control method and this is believed to be because of the considerably different volatilities of the chemicals. Given the combination of health hazard and exposure potential components, the COSHH Essentials model recommended a control approach 'special advice' for both tasks, based on the potential reproductive hazard ascribed to toluene. This would not have been the same conclusion if some other chemical had been substituted (for example styrene, which has the same threshold limit value as toluene). Nevertheless, it was special advice, which had led to the combination of hygienic procedures in place at this plant. The probability of the combined exposure fractions exceeding unity was 0.0002 for the batch-making task indicating that the employees performing this task were most likely well protected below the OELs. Although the employees involved in the bucket-washing task had greater potential to exceed the threshold limit value of the mixture (P > 1 = 0.2375), the expected personal exposure after adjusting for the assigned protection factor for the respirators in use would be considerably lower (P > 1 = 0.0161). Thus, our findings suggested that the COSHH essentials model worked reasonably well for the volatile organic chemicals at the plant. However, it was difficult to override the reproductive hazard even though it was meant to be possible in principle. Further, it became apparent that an input of existing controls, which is not possible in the web-based model, may have allowed the model be more widely applicable. The experience of using the web-based COSHH Essentials model generated some suggestions to provide a more user-friendly tool to the model users who do not have expertise in occupational hygiene.

Biological effects from electromagnetic field exposure and public exposure standards.

PubMed

Hardell, Lennart; Sage, Cindy

2008-02-01

During recent years there has been increasing public concern on potential health risks from power-frequency fields (extremely low frequency electromagnetic fields; ELF) and from radiofrequency/microwave radiation emissions (RF) from wireless communications. Non-thermal (low-intensity) biological effects have not been considered for regulation of microwave exposure, although numerous scientific reports indicate such effects. The BioInitiative Report is based on an international research and public policy initiative to give an overview of what is known of biological effects that occur at low-intensity electromagnetic fields (EMFs) exposure. Health endpoints reported to be associated with ELF and/or RF include childhood leukaemia, brain tumours, genotoxic effects, neurological effects and neurodegenerative diseases, immune system deregulation, allergic and inflammatory responses, breast cancer, miscarriage and some cardiovascular effects. The BioInitiative Report concluded that a reasonable suspicion of risk exists based on clear evidence of bioeffects at environmentally relevant levels, which, with prolonged exposures may reasonably be presumed to result in health impacts. Regarding ELF a new lower public safety limit for habitable space adjacent to all new or upgraded power lines and for all other new constructions should be applied. A new lower limit should also be used for existing habitable space for children and/or women who are pregnant. A precautionary limit should be adopted for outdoor, cumulative RF exposure and for cumulative indoor RF fields with considerably lower limits than existing guidelines, see the BioInitiative Report. The current guidelines for the US and European microwave exposure from mobile phones, for the brain are 1.6 W/Kg and 2 W/Kg, respectively. Since use of mobile phones is associated with an increased risk for brain tumour after 10 years, a new biologically based guideline is warranted. Other health impacts associated with exposure to electromagnetic fields not summarized here may be found in the BioInitiative Report at www.bioinitiative.org.

Mobile phone radiation alters proliferation of hepatocarcinoma cells.

PubMed

Ozgur, Elcin; Guler, Goknur; Kismali, Gorkem; Seyhan, Nesrin

2014-11-01

This study investigated the effects of intermittent exposure (15 min on, 15 min off for 1, 2, 3, or 4 h, at a specific absorption rate of 2 W/kg) to enhanced data rates for global system for mobile communication evolution-modulated radiofrequency radiation (RFR) at 900- and 1,800-MHz frequencies on the viability of the Hepatocarcinoma cells (Hep G2). Hep G2 cell proliferation was measured by a colorimetric assay based on the cleavage of the tetrazolium salt WST-1 by mitochondrial dehydrogenases in viable cells. Cell injury was evaluated by analyzing the levels of lactate dehydrogenase (LDH) and glucose released from lysed cells into the culture medium. Morphological observation of the nuclei was carried out by 4',6-diamidino-2-phenylindole (DAPI) staining using fluorescence microscopy. In addition, TUNEL assay was performed to confirm apoptotic cell death. It was observed that cell viability, correlated with the LDH and glucose levels, changed according to the frequency and duration of RFR exposure. Four-hour exposure produced more pronounced effects than the other exposure durations. 1,800-MHz RFR had a larger impact on cell viability and Hep G2 injury than the RFR at 900 MHz. Morphological observations also supported the biochemical results indicating that most of the cells showed irregular nuclei pattern determined by using the DAPI staining, as well as TUNEL assay which shows DNA damage especially in the cells after 4 h of exposure to 1,800-MHz RFR. Our results indicate that the applications of 900- and 1,800-MHz (2 W/kg) RFR cause to decrease in the proliferation of the Hep G2 cells after 4 h of exposure. Further studies will be conducted on other frequency bands of RFR and longer duration of exposure.

Temporal changes in taxonomic and functional diversity of fish assemblages downstream from mountaintop mining

USGS Publications Warehouse

Hitt, Nathaniel P.; Chambers, Douglas B.

2014-01-01

Mountaintop mining (MTM) affects chemical, physical, and hydrological properties of receiving streams, but the long-term consequences for fish-assemblage structure and function are poorly understood. We sampled stream fish assemblages using electrofishing techniques in MTM exposure sites and reference sites within the Guyandotte River basin, USA, during 2010–2011. We calculated indices of taxonomic diversity (species richness, abundance, Shannon diversity) and functional diversity (functional richness, functional evenness, functional divergence) to compare exposure and reference assemblages between seasons (spring and autumn) and across years (1999–2011). We based temporal comparisons on 2 sites that were sampled during 1999–2001 by Stauffer and Ferreri (2002). Exposure assemblages had lower taxonomic and functional diversity than reference assemblages or simulated assemblages that accounted for random variation. Differences in taxonomic composition between reference and exposure assemblages were associated with conductivity and aqueous Se concentrations. Exposure assemblages had fewer species, lower abundances, and less biomass than reference assemblages across years and seasons. Green Sunfish (Lepomis cyanellus) and Creek Chub (Semotilus atromaculatus) became numerically dominant in exposure assemblages over time because of their persistence and losses of other taxa. In contrast, species richness increased over time in reference assemblages, a result that may indicate recovery from drought. Mean individual biomass increased as fish density decreased and most obligate invertivores were apparently extirpated at MTM exposure sites. Effects of MTM were not related to physical-habitat conditions but were associated with water-quality variables, which may limit quality and availability of benthic macroinvertebrate prey. Simulations revealed effects of MTM that could not be attributed to random variation in fish assemblage structure.

Occupational exposure to indoor air pollution among bakery workers in Ethiopia; A comparison of electric and biomass cookstoves.

PubMed

Downward, George S; van der Zwaag, Hugo P; Simons, Leon; Meliefste, Kees; Tefera, Yifokire; Carreon, J Rosales; Vermeulen, Roel; Smit, Lidwien A M

2018-02-01

The indoor air pollution (IAP) produced by the domestic combustion of solid fuels is responsible for up to 4 million deaths annually, especially among low and middle income countries. Occupational exposure within the food preparation industries of these nations remains underexplored. We investigated occupational exposure to the IAP produced during the commercial production of injera, a staple of the Ethiopian diet, from bakeries in Addis Ababa, Ethiopia. Measurements of PM 2.5 , black carbon (via the proxy measure PM 2.5 absorbance) and CO were collected from 30 bakeries and their employees for an average of 4-h per working day. Measurements were compared between bakeries using biomass and electric cookstoves. Further, the respiratory health data of 35 bakery employees were collected by interview-based questionnaire. Personal exposure to PM2.5 from biomass cookstoves was double that of electric cookstoves (430 μg/m3 vs. 216 μg/m3), black carbon exposure was four times higher among biomass users (67 × 10-5m-1 vs. 15 × 10-5m-1), and CO exposure was twenty times higher among biomass users (22 ppm vs. 1 ppm). Mixed effect models indicated that the number of stoves in use and additional solid fuel usage (e.g. coffee brewing) also contributed to exposure levels. These findings indicate that the use of biomass powered cookstoves during commercial injera production significantly contributes to IAP and self-reported respiratory symptoms. As injera is the staple foodstuff of Ethiopia, a widespread conversion to electric cookstoves is likely to have a significant impact. However, as high levels of IAP were also observed within the electric bakeries, further identification of pollution sources is required. Copyright © 2017 Elsevier Ltd. All rights reserved.

Repeated exposures to diisopropylfluorophosphate result in impairments of sustained attention and persistent alterations of inhibitory response control in rats

PubMed Central

Terry, Alvin V.; Callahan, Patrick M.; Beck, Wayne D.; Vandenhuerk, Leah; Sinha, Samantha; Bouchard, Kristy; Schade, Rose; Waller, Jennifer L.

2014-01-01

Organophosphate (OP)-based chemicals are used worldwide for many purposes and they have likely saved millions of people from starvation and disease. However, due to their toxicity they can also pose a significant environmental risk. While considerable research has focused on the acute symptoms and long-term consequences of overtly toxic exposures to OPs, less attention has been given to the subject of repeated exposures to levels that are not associated with acute symptoms (subthreshold exposures). There is clinical evidence indicating that this type of OP exposure can lead to prolonged deficits in cognition; however only a few studies have addressed this issue prospectively in animal models. In this study, repeated subthreshold exposures to the OP nerve agent diisopropylfluorophosphate (DFP) were evaluated in a 5-Choice Serial Reaction Time Task (5C-SRTT), an animal model of sustained attention. Adult rats were trained to stably perform the 5C-SRTT and then injected subcutaneously with vehicle or DFP 0.5 mg/kg every other day for 30 days. Behavioral testing occurred daily during the DFP-exposure period and throughout a 45 day (OP-free) washout period. Compared to vehicle-treated controls, DFP-treated rats exhibited deficits in accuracy, increases in omissions and timeout responses during the OP exposure period, while no significant effects on premature responses, perseverative responses, or response latencies were noted. While the increase in timeout responses remained detectible during washout, all other DFP-related alterations in 5C-SRTT performance abated. When the demands of the task were increased by the presentation of variable intertrial intervals, premature responses were also elevated in DFP-treated rats during the washout period. These results indicate that repeated exposures to subthreshold doses of DFP lead to reversible impairments in sustained attention as well as persistent impairments of inhibitory response control in rats. PMID:24819591

An evaluation of the toxicity of potassium chloride, active compound in the molluscicide potash, on salmonid fish and their forage base

USGS Publications Warehouse

Densmore, Christine L.; Iwanowicz, Luke R.; Henderson, Anne P.; Blazer, Vicki S.; Reed-Grimmett, Baileigh M.; Sanders, Lakyn R.

2018-06-29

Potash, with the active ingredient potassium chloride (KCl) is a chemical that is currently being evaluated for potential use as a molluscicide to combat invasive zebra mussels and quagga mussels in Western United States waters. Although data available for other freshwater fishes indicate that recommended treatment levels of potash as a molluscicide are sublethal, this has not been demonstrated for all salmonid species. The objectives of this study were to perform toxicity testing to determine the lethality of potassium chloride against selected species of salmonid fish (brook trout and Chinook salmon) and selected invertebrate forage, and to identify any potential adverse physiological impacts of KCl to these salmonids in water at treatment levels used for mollusk eradication. Minimal mortality (n=1 fish) was observed during 96-hour toxicity testing at KCl concentrations of 0 to 800 milligrams per liter (mg/L), indicating that the lethal concentration (LC50) values in these salmonid species were considerably higher than realistic molluscicide treatment concentrations. Sublethal effects were examined through evaluation of behavioral and morphological (histological) observation as well as specific blood chemistry parameters (electrolytes, osmolality, glucose, and cortisol). There was no strong evidence of significant physiological impairment among the two salmonid species due to KCl exposure. Whereas statistically significant differences in some parameters were observed in association with KCl treatments, it is unlikely that these differences indicate adverse biological impacts. Acute toxicity tests were conducted with invertebrate species at KCl exposure concentrations of 0–3,200 mg/L. Daphniid exposure trials resulted in differences in mortality among the test groups with higher mortality evident among the higher KCl exposure concentrations with a calculated LC50 value of 196 mg/L KCl for a 48-hour exposure. Crayfish exposed to higher concentrations of KCl at or above 800 mg/L as specimens exhibited death or reversible paralysis. Chironomid larvae exposures were largely inconclusive because of cannibalistic behavior among the various test groups.

Cationic peptide exposure enhances pulsed-electric-field-mediated membrane disruption.

PubMed

Kennedy, Stephen M; Aiken, Erik J; Beres, Kaytlyn A; Hahn, Adam R; Kamin, Samantha J; Hagness, Susan C; Booske, John H; Murphy, William L

2014-01-01

The use of pulsed electric fields (PEFs) to irreversibly electroporate cells is a promising approach for destroying undesirable cells. This approach may gain enhanced applicability if the intensity of the PEF required to electrically disrupt cell membranes can be reduced via exposure to a molecular deliverable. This will be particularly impactful if that reduced PEF minimally influences cells that are not exposed to the deliverable. We hypothesized that the introduction of charged molecules to the cell surfaces would create regions of enhanced transmembrane electric potential in the vicinity of each charged molecule, thereby lowering the PEF intensity required to disrupt the plasma membranes. This study will therefore examine if exposure to cationic peptides can enhance a PEF's ability to disrupt plasma membranes. We exposed leukemia cells to 40 μs PEFs in media containing varying concentrations of a cationic peptide, polyarginine. We observed the internalization of a membrane integrity indicator, propidium iodide (PI), in real time. Based on an individual cell's PI fluorescence versus time signature, we were able to determine the relative degree of membrane disruption. When using 1-2 kV/cm, exposure to >50 μg/ml of polyarginine resulted in immediate and high levels of PI uptake, indicating severe membrane disruption, whereas in the absence of peptide, cells predominantly exhibited signatures indicative of no membrane disruption. Additionally, PI entered cells through the anode-facing membrane when exposed to cationic peptide, which was theoretically expected. Exposure to cationic peptides reduced the PEF intensity required to induce rapid and irreversible membrane disruption. Critically, peptide exposure reduced the PEF intensities required to elicit irreversible membrane disruption at normally sub-electroporation intensities. We believe that these cationic peptides, when coupled with current advancements in cell targeting techniques will be useful tools in applications where targeted destruction of unwanted cell populations is desired.

Cationic Peptide Exposure Enhances Pulsed-Electric-Field-Mediated Membrane Disruption

PubMed Central

Kennedy, Stephen M.; Aiken, Erik J.; Beres, Kaytlyn A.; Hahn, Adam R.; Kamin, Samantha J.; Hagness, Susan C.; Booske, John H.; Murphy, William L.

2014-01-01

Background The use of pulsed electric fields (PEFs) to irreversibly electroporate cells is a promising approach for destroying undesirable cells. This approach may gain enhanced applicability if the intensity of the PEF required to electrically disrupt cell membranes can be reduced via exposure to a molecular deliverable. This will be particularly impactful if that reduced PEF minimally influences cells that are not exposed to the deliverable. We hypothesized that the introduction of charged molecules to the cell surfaces would create regions of enhanced transmembrane electric potential in the vicinity of each charged molecule, thereby lowering the PEF intensity required to disrupt the plasma membranes. This study will therefore examine if exposure to cationic peptides can enhance a PEF’s ability to disrupt plasma membranes. Methodology/Principal Findings We exposed leukemia cells to 40 μs PEFs in media containing varying concentrations of a cationic peptide, polyarginine. We observed the internalization of a membrane integrity indicator, propidium iodide (PI), in real time. Based on an individual cell’s PI fluorescence versus time signature, we were able to determine the relative degree of membrane disruption. When using 1–2 kV/cm, exposure to >50 μg/ml of polyarginine resulted in immediate and high levels of PI uptake, indicating severe membrane disruption, whereas in the absence of peptide, cells predominantly exhibited signatures indicative of no membrane disruption. Additionally, PI entered cells through the anode-facing membrane when exposed to cationic peptide, which was theoretically expected. Conclusions/Significance Exposure to cationic peptides reduced the PEF intensity required to induce rapid and irreversible membrane disruption. Critically, peptide exposure reduced the PEF intensities required to elicit irreversible membrane disruption at normally sub-electroporation intensities. We believe that these cationic peptides, when coupled with current advancements in cell targeting techniques will be useful tools in applications where targeted destruction of unwanted cell populations is desired. PMID:24671150

The relation between input-output transformation and gastrointestinal nematode infections on dairy farms.

PubMed

van der Voort, M; Van Meensel, J; Lauwers, L; Van Huylenbroeck, G; Charlier, J

2016-02-01

Efficiency analysis is used for assessing links between technical efficiency (TE) of livestock farms and animal diseases. However, previous studies often do not make the link with the allocation of inputs and mainly present average effects that ignore the often huge differences among farms. In this paper, we studied the relationship between exposure to gastrointestinal (GI) nematode infections, the TE and the input allocation on dairy farms. Although the traditional cost allocative efficiency (CAE) indicator adequately measures how a given input allocation differs from the cost-minimising input allocation, they do not represent the unique input allocation of farms. Similar CAE scores may be obtained for farms with different input allocations. Therefore, we propose an adjusted allocative efficiency index (AAEI) to measure the unique input allocation of farms. Combining this AAEI with the TE score allows determining the unique input-output position of each farm. The method is illustrated by estimating efficiency scores using data envelopment analysis (DEA) on a sample of 152 dairy farms in Flanders for which both accountancy and parasitic monitoring data were available. Three groups of farms with a different input-output position can be distinguished based on cluster analysis: (1) technically inefficient farms, with a relatively low use of concentrates per 100 l milk and a high exposure to infection, (2) farms with an intermediate TE, relatively high use of concentrates per 100 l milk and a low exposure to infection, (3) farms with the highest TE, relatively low roughage use per 100 l milk and a relatively high exposure to infection. Correlation analysis indicates for each group how the level of exposure to GI nematodes is associated or not with improved economic performance. The results suggest that improving both the economic performance and exposure to infection seems only of interest for highly TE farms. The findings indicate that current farm recommendations regarding GI nematode infections could be improved by also accounting for the allocation of inputs on the farm.

A critical review and analysis of the use of exposure- and flux-based ozone indices for predicting vegetation effects

Treesearch

Robert C. Musselman; Allen S. Lefohn; William J. Massman; Robert L. Heath

2006-01-01

Early studies of plant response to ozone (O3) utilized concentration-based metrics, primarily by summarizing the commonly monitored hourly average data sets. Research with the O3 concentration parameter led to the recognition that both peak concentrations and cumulative effects are important when relating plant response to O3. The US and Canada currently use O3...

Chronic Arsenic Poisoning Probably Caused by Arsenic-Based Pesticides: Findings from an Investigation Study of a Household

PubMed Central

Li, Yongfang; Ye, Feng; Wang, Anwei; Wang, Da; Yang, Boyi; Zheng, Quanmei; Sun, Guifan; Gao, Xinghua

2016-01-01

In addition to naturally occurring arsenic, man-made arsenic-based compounds are other sources of arsenic exposure. In 2013, our group identified 12 suspected arsenicosis patients in a household (32 living members). Of them, eight members were diagnosed with skin cancer. Interestingly, all of these patients had lived in the household prior to 1989. An investigation revealed that approximately 2 tons of arsenic-based pesticides had been previously placed near a well that had supplied drinking water to the family from 1973 to 1989. The current arsenic level in the well water was 620 μg/L. No other high arsenic wells were found near the family’s residence. Based on these findings, it is possible to infer that the skin lesions exhibited by these family members were caused by long-term exposure to well water contaminated with arsenic-based pesticides. Additionally, biochemical analysis showed that the individuals exposed to arsenic had higher levels of aspartate aminotransferase and γ-glutamyl transpeptidase than those who were not exposed. These findings might indicate the presence of liver dysfunction in the arsenic-exposed individuals. This report elucidates the effects of arsenical compounds on the occurrence of high levels of arsenic in the environment and emphasizes the severe human health impact of arsenic exposure. PMID:26784217

Chronic Arsenic Poisoning Probably Caused by Arsenic-Based Pesticides: Findings from an Investigation Study of a Household.

PubMed

Li, Yongfang; Ye, Feng; Wang, Anwei; Wang, Da; Yang, Boyi; Zheng, Quanmei; Sun, Guifan; Gao, Xinghua

2016-01-16

In addition to naturally occurring arsenic, man-made arsenic-based compounds are other sources of arsenic exposure. In 2013, our group identified 12 suspected arsenicosis patients in a household (32 living members). Of them, eight members were diagnosed with skin cancer. Interestingly, all of these patients had lived in the household prior to 1989. An investigation revealed that approximately 2 tons of arsenic-based pesticides had been previously placed near a well that had supplied drinking water to the family from 1973 to 1989. The current arsenic level in the well water was 620 μg/L. No other high arsenic wells were found near the family's residence. Based on these findings, it is possible to infer that the skin lesions exhibited by these family members were caused by long-term exposure to well water contaminated with arsenic-based pesticides. Additionally, biochemical analysis showed that the individuals exposed to arsenic had higher levels of aspartate aminotransferase and γ-glutamyl transpeptidase than those who were not exposed. These findings might indicate the presence of liver dysfunction in the arsenic-exposed individuals. This report elucidates the effects of arsenical compounds on the occurrence of high levels of arsenic in the environment and emphasizes the severe human health impact of arsenic exposure.

Impact of Fire Suit Ensembles on Firefighter PAH Exposures as Assessed by Skin Deposition and Urinary Biomarkers.

PubMed

Wingfors, Håkan; Nyholm, Jenny Rattfelt; Magnusson, Roger; Wijkmark, Cecilia Hammar

2018-02-13

Over the past 10 years, a number of safety measures for reducing firefighters' exposure to combustion particles have been introduced in Sweden. The most important measure was the reduction in the time firefighters wear suits and handle contaminated equipment after turn-outs involving smoke diving. This study was divided into two parts, those being to investigate the level of protection obtained by multiple garment layers and to assess exposure during a standardized smoke diving exercise. First, realistic work protection factors (WPFs) were calculated by comparing air concentrations of the full suite of gaseous and particle-bound polycyclic aromatic hydrocarbons (PAHs) inside and outside structural ensembles, including jacket and thick base layer, during a tough fire extinguishing exercise using wood as the fuel. Second, during a standardized smoke diving exercise, exposure was assessed by measuring PAH skin deposition and levels of eight urinary PAH metabolites in 20 volunteer student firefighters before and after the exercise. The average WPF for the sum of 22 PAHs was 146 ± 33 suggesting a relatively high protective capacity but also indicating a substantial enrichment of contaminants with a risk of prolonged dermal exposure. Accordingly, in the second exercise, the median levels of skin-deposited Σ14-PAHs and urinary 1-hydroxypyrene significantly increased 5-fold (21 to 99 ng/wipe) and 8-fold (0.14 to 1.1 µmol mol-1 creatinine), respectively, post exposure. Among the PAH metabolites investigated, 1-hydroxypyrene proved to be the most useful indicator of exposure, with significantly elevated urinary levels at both 6 h and 20 h after the exercise and with the strongest correlation to dermal exposure. Metabolites from two-ring and three-ring PAHs were eliminated faster while levels of 3-hydroxy-benzo[a]pyrene did not meet the detection criteria. The results from correlation studies indicated that dermal uptake was a major route of exposure in accordance with previous findings. To summarize, this study shows that some of the newly adopted protective measures were correctly implemented, and should continue to be followed and be more widely adopted. © The Author(s) 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

Effects of rock wool on the lungs evaluated by magnetometry and biopersistence test

PubMed Central

Kudo, Yuichiro; Kotani, Makoto; Tomita, Masayuki; Aizawa, Yoshiharu

2009-01-01

Background Asbestos has been reported to cause pulmonary fibrosis, and its use has been banned all over the world. The related industries are facing an urgent need to develop a safer fibrous substance. Rock wool (RW), a kind of asbestos substitute, is widely used in the construction industry. In order to evaluate the safety of RW, we performed a nose-only inhalation exposure study in rats. After one-month observation period, the potential of RW fibers to cause pulmonary toxicity was evaluated based on lung magnetometry findings, pulmonary biopersistence, and pneumopathology. Methods Using the nose-only inhalation exposure system, 6 male Fischer 344 rats (6 to 10 weeks old) were exposed to RW fibers at a target fiber concentration of 100 fibers/cm3 (length [L] > 20 μm) for 6 hours daily, for 5 consecutive days. As a magnetometric indicator, 3 mg of triiron tetraoxide suspended in 0.2 mL of physiological saline was intratracheally administered after RW exposure to these rats and 6 unexposed rats (controls). During one second magnetization in 50 mT external magnetic field, all magnetic particles were aligned, and immediately afterwards the strength of their remanent magnetic field in the rat lungs was measured in both groups. Magnetization and measurement of the decay (relaxation) of this remanent magnetic field was performed over 40 minutes on 1, 3, 14, and 28 days after RW exposure, and reflected cytoskeleton dependent intracellular transport within macrophages in the lung. Similarly, 24 and 12 male Fisher 344-rats were used for biopersistence test and pathologic evaluation, respectively. Results In the lung magnetometric evaluation, biopersistence test and pathological evaluation, the arithmetic mean value of the total fiber concentration was 650.2, 344.7 and 390.7 fibers/cm3, respectively, and 156.6, 93.1 and 95.0 fibers/cm3 for fibers with L > 20 μm, respectively. The lung magnetometric evaluation revealed that impaired relaxation indicating cytoskeletal toxicity did not occur in the RW exposure group. In addition, clearance of the magnetic tracer particles was not significantly affected by the RW exposure. No effects on lung pathology were noted after RW exposure. Conclusion These findings indicate that RW exposure is unlikely to cause pulmonary toxicity within four weeks period. Lung magnetometry studies involving long-term exposure and observation will be necessary to ensure the safety of RW. PMID:19323845

Risk assessment of combined exposure to alkenylbenzenes through consumption of plant food supplements containing parsley and dill.

PubMed

Alajlouni, Abdalmajeed M; Al-Malahmeh, Amer J; Wesseling, Sebastiaan; Kalli, Marina; Vervoort, Jacques; Rietjens, Ivonne M C M

2017-12-01

A risk assessment was performed of parsley- and dill-based plant food supplements (PFS) containing apiol and related alkenylbenzenes. First, the levels of the alkenylbenzenes in the PFS and the resulting estimated daily intake (EDI) resulting from use of the PFS were quantified. Since most PFS appeared to contain more than one alkenylbenzene, a combined risk assessment was performed based on equal potency or using a so-called toxic equivalency (TEQ) approach based on toxic equivalency factors (TEFs) for the different alkenylbenzenes. The EDIs resulting from daily PFS consumption amount to 0.74-125 µg kg -1 bw for the individual alkenylbenzenes, 0.74-160 µg kg -1 bw for the sum of the alkenylbenzenes, and 0.47-64 µg kg -1 bw for the sum of alkenylbenzenes when expressed in safrole equivalents. The margins of exposure (MOEs) obtained were generally below 10,000, indicating a priority for risk management if the PFS were to be consumed on a daily basis. Considering short-term use of the PFS, MOEs would increase above 10,000, indicating low priority for risk management. It is concluded that alkenylbenzene intake through consumption of parsley- and dill-based PFS is only of concern when these PFS are used for long periods of time.

Protective effect of Uncaria tomentosa extract against oxidative stress and genotoxicity induced by glyphosate-Roundup® using zebrafish (Danio rerio) as a model.

PubMed

Santo, Glaucia Dal; Grotto, Alan; Boligon, Aline A; Da Costa, Bárbara; Rambo, Cassiano L; Fantini, Emily A; Sauer, Elisa; Lazzarotto, Luan M V; Bertoncello, Kanandra T; Júnior, Osmar Tomazelli; Garcia, Solange C; Siebel, Anna M; Rosemberg, Denis B; Magro, Jacir Dal; Conterato, Greicy M M; Zanatta, Leila

2018-04-01

Oxidative stress and DNA damage are involved in the glyphosate-based herbicide toxicity. Uncaria tomentosa (UT; Rubiaceae) is a plant species from South America containing bioactive compounds with known beneficial properties. The objective of this work was to evaluate the antioxidant and antigenotoxic potential of UT extract in a model of acute exposure to glyphosate-Roundup® (GR) in zebrafish (Danio rerio). We showed that UT (1.0 mg/mL) prevented the decrease of brain total thiols, the increase of lipid peroxidation in both brain and liver, and the decrease of liver GPx activity caused after 96 h of GR (5.0 mg/L) exposure. In addition, UT partially protected against the increase of micronucleus frequency induced by GR exposure in fish brain. Overall, our results indicate that UT protects against damage induced by a glyphosate-based herbicide by providing antioxidant and antigenotoxic effects, which may be related to the phenolic compounds identified in the extract.

Chaotic time series prediction for prenatal exposure to polychlorinated biphenyls in umbilical cord blood using the least squares SEATR model

NASA Astrophysics Data System (ADS)

Xu, Xijin; Tang, Qian; Xia, Haiyue; Zhang, Yuling; Li, Weiqiu; Huo, Xia

2016-04-01

Chaotic time series prediction based on nonlinear systems showed a superior performance in prediction field. We studied prenatal exposure to polychlorinated biphenyls (PCBs) by chaotic time series prediction using the least squares self-exciting threshold autoregressive (SEATR) model in umbilical cord blood in an electronic waste (e-waste) contaminated area. The specific prediction steps basing on the proposal methods for prenatal PCB exposure were put forward, and the proposed scheme’s validity was further verified by numerical simulation experiments. Experiment results show: 1) seven kinds of PCB congeners negatively correlate with five different indices for birth status: newborn weight, height, gestational age, Apgar score and anogenital distance; 2) prenatal PCB exposed group at greater risks compared to the reference group; 3) PCBs increasingly accumulated with time in newborns; and 4) the possibility of newborns suffering from related diseases in the future was greater. The desirable numerical simulation experiments results demonstrated the feasibility of applying mathematical model in the environmental toxicology field.

Chaotic time series prediction for prenatal exposure to polychlorinated biphenyls in umbilical cord blood using the least squares SEATR model

PubMed Central

Xu, Xijin; Tang, Qian; Xia, Haiyue; Zhang, Yuling; Li, Weiqiu; Huo, Xia

2016-01-01

Chaotic time series prediction based on nonlinear systems showed a superior performance in prediction field. We studied prenatal exposure to polychlorinated biphenyls (PCBs) by chaotic time series prediction using the least squares self-exciting threshold autoregressive (SEATR) model in umbilical cord blood in an electronic waste (e-waste) contaminated area. The specific prediction steps basing on the proposal methods for prenatal PCB exposure were put forward, and the proposed scheme’s validity was further verified by numerical simulation experiments. Experiment results show: 1) seven kinds of PCB congeners negatively correlate with five different indices for birth status: newborn weight, height, gestational age, Apgar score and anogenital distance; 2) prenatal PCB exposed group at greater risks compared to the reference group; 3) PCBs increasingly accumulated with time in newborns; and 4) the possibility of newborns suffering from related diseases in the future was greater. The desirable numerical simulation experiments results demonstrated the feasibility of applying mathematical model in the environmental toxicology field. PMID:27118260

MicroRNA Expression Profiling of the Armed Forces Health Surveillance Branch Cohort for Identification of "Enviro-miRs" Associated With Deployment-Based Environmental Exposure.

PubMed

Dalgard, Clifton L; Polston, Keith F; Sukumar, Gauthaman; Mallon, Col Timothy M; Wilkerson, Matthew D; Pollard, Harvey B

2016-08-01

The aim of this study was to identify serum microRNA (miRNA) biomarkers that indicate deployment-associated exposures in service members at military installations with open burn pits. Another objective was to determine detection rates of miRNAs in Department of Defense Serum Repository (DoDSR) samples with a high-throughput methodology. Low-volume serum samples (n = 800) were profiled by miRNA-capture isolation, pre-amplification, and measurement by a quantitative PCR-based OpenArray platform. Normalized quantitative cycle values were used for differential expression analysis between groups. Assay specificity, dynamic range, reproducibility, and detection rates by OpenArray passed target desired specifications. Serum abundant miRNAs were consistently measured in study specimens. Four miRNAs were differentially expressed in the case deployment group subjects. miRNAs are suitable RNA species for biomarker discovery in the DoDSR serum specimens. Serum miRNAs are candidate biomarkers for deployment and environmental exposure in military service members.

Wildland smoke exposure values and exhaled breath indicators in firefighters.

PubMed

Miranda, Ana Isabel; Martins, Vera; Cascão, Pedro; Amorim, Jorge Humberto; Valente, Joana; Borrego, Carlos; Ferreira, António Jorge; Cordeiro, Carlos Robalo; Viegas, Domingos Xavier; Ottmar, Roger

2012-01-01

Smoke from forest fires contains significant amounts of gaseous and particulate pollutants. Firefighters exposed to wildland fire smoke can suffer from several acute and chronic adverse health effects. Consequently, exposure data are of vital importance for the establishment of cause/effect relationships between exposure to smoke and firefighter health effects. The aims of this study were to (1) characterize the relationship between wildland smoke exposure and medical parameters and (2) identify health effects pertinent to wildland forest fire smoke exposure. In this study, firefighter exposure levels of carbon monoxide (CO), nitrogen dioxide (NO₂), and volatile organic compounds (VOC) were measured in wildfires during three fire seasons in Portugal. Personal monitoring devices were used to measure exposure. Firefighters were also tested for exhaled nitric oxide (eNO) and CO before and after their firefighting activities. Data indicated that exposure levels during firefighting activities were beyond limits recommended by the Occupational Exposure Standard (OES) values. Medical tests conducted on the firefighters also indicated a considerable effect on measured medical parameters, with a significant increase in CO and decrease in NO in exhaled air of majority of the firefighters.

Trauma exposure and the mediating role of posttraumatic stress on somatic symptoms in civilian war victims.

PubMed

Morina, Naser; Schnyder, Ulrich; Klaghofer, Richard; Müller, Julia; Martin-Soelch, Chantal

2018-04-10

It has been well documented that the exposure to war has a negative effect on the psychological health of civilian. However, little is known on the impact of war exposure on the physical health of the civilian population. In addition, the link between trauma exposure and somatic symptoms remain poorly understood. This cross-sectional study examined levels of somatic symptoms in the aftermath of war, and the mediating role of posttraumatic stress symptoms in the relationship between trauma exposure and somatic symptoms. Civilian war survivors (N = 142) from Kosovo were assessed for potentially traumatic events, posttraumatic stress symptoms, and somatic symptoms. Data were analyzed using mediation analyses. Posttraumatic stress disorder (PTSD) symptoms were categorized based on King's four factor model (Psychol Assessment. 10: 90-96, 1998). Participants reported on average more than 5 types of traumatic exposure. The cut-off indicative for PTSD was exceeded by 26.1% of participants. Symptom levels of PTSD were associated with somatic symptoms. The relationship between trauma exposure and somatic symptoms was partly mediated by the active avoidance and hyperarousal symptom clusters of PTSD. Active avoidance and hyperarousal symptoms seem to play a key role in traumatized people suffering from somatic symptoms.

Public Exposure from Indoor Radiofrequency Radiation in the City of Hebron, West Bank-Palestine.

PubMed

Lahham, Adnan; Sharabati, Afefeh; ALMasri, Hussien

2015-08-01

This work presents the results of measured indoor exposure levels to radiofrequency (RF) radiation emitting sources in one of the major cities in the West Bank-the city of Hebron. Investigated RF emitters include FM, TV broadcasting stations, mobile telephony base stations, cordless phones [Digital Enhanced Cordless Telecommunications (DECT)], and wireless local area networks (WLAN). Measurements of power density were conducted in 343 locations representing different site categories in the city. The maximum total power density found at any location was about 2.3 × 10 W m with a corresponding exposure quotient of about 0.01. This value is well below unity, indicating compliance with the guidelines of the International Commission on Non-ionizing Radiation Protection (ICNIRP). The average total exposure from all RF sources was 0.08 × 10 W m. The relative contributions from different sources to the total exposure in terms of exposure quotient were evaluated and found to be 46% from FM radio, 26% from GSM900, 15% from DECT phones, 9% from WLAN, 3% from unknown sources, and 1% from TV broadcasting. RF sources located outdoors contribute about 73% to the population exposure indoors.

The Diesel Exhaust in Miners Study: I. Overview of the Exposure Assessment Process

PubMed Central

Stewart, Patricia A.; Coble, Joseph B.; Vermeulen, Roel; Schleiff, Patricia; Blair, Aaron; Lubin, Jay; Attfield, Michael; Silverman, Debra T.

2010-01-01

This report provides an overview of the exposure assessment process for an epidemiologic study that investigated mortality, with a special focus on lung cancer, associated with diesel exhaust (DE) exposure among miners. Details of several components are provided in four other reports. A major challenge for this study was the development of quantitative estimates of historical exposures to DE. There is no single standard method for assessing the totality of DE, so respirable elemental carbon (REC), a component of DE, was selected as the primary surrogate in this study. Air monitoring surveys at seven of the eight study mining facilities were conducted between 1998 and 2001 and provided reference personal REC exposure levels and measurements for other agents and DE components in the mining environment. (The eighth facility had closed permanently prior to the surveys.) Exposure estimates were developed for mining facility/department/job/year combinations. A hierarchical grouping strategy was developed for assigning exposure levels to underground jobs [based on job titles, on the amount of time spent in various areas of the underground mine, and on similar carbon monoxide (CO, another DE component) concentrations] and to surface jobs (based on the use of, or proximity to, diesel-powered equipment). Time trends in air concentrations for underground jobs were estimated from mining facility-specific prediction models using diesel equipment horsepower, total air flow rates exhausted from the underground mines, and, because there were no historical REC measurements, historical measurements of CO. Exposures to potentially confounding agents, i.e. respirable dust, silica, radon, asbestos, and non-diesel sources of polycyclic aromatic hydrocarbons, also were assessed. Accuracy and reliability of the estimated REC exposures levels were evaluated by comparison with several smaller datasets and by development of alternative time trend models. During 1998–2001, the average measured REC exposure level by facility ranged from 40 to 384 μg m−3 for the underground workers and from 2 to 6 μg m−3 for the surface workers. For one prevalent underground job, ‘miner operator’, the maximum annual REC exposure estimate by facility ranged up to 685% greater than the corresponding 1998–2001 value. A comparison of the historical CO estimates from the time trend models with 1976–1977 CO measurements not used in the modeling found an overall median relative difference of 29%. Other comparisons showed similar levels of agreement. The assessment process indicated large differences in REC exposure levels over time and across the underground operations. Method evaluations indicated that the final estimates were consistent with those from alternative time trend models and demonstrated moderate to high agreement with external data. PMID:20876233

The diesel exhaust in miners study: I. Overview of the exposure assessment process.

PubMed

Stewart, Patricia A; Coble, Joseph B; Vermeulen, Roel; Schleiff, Patricia; Blair, Aaron; Lubin, Jay; Attfield, Michael; Silverman, Debra T

2010-10-01

This report provides an overview of the exposure assessment process for an epidemiologic study that investigated mortality, with a special focus on lung cancer, associated with diesel exhaust (DE) exposure among miners. Details of several components are provided in four other reports. A major challenge for this study was the development of quantitative estimates of historical exposures to DE. There is no single standard method for assessing the totality of DE, so respirable elemental carbon (REC), a component of DE, was selected as the primary surrogate in this study. Air monitoring surveys at seven of the eight study mining facilities were conducted between 1998 and 2001 and provided reference personal REC exposure levels and measurements for other agents and DE components in the mining environment. (The eighth facility had closed permanently prior to the surveys.) Exposure estimates were developed for mining facility/department/job/year combinations. A hierarchical grouping strategy was developed for assigning exposure levels to underground jobs [based on job titles, on the amount of time spent in various areas of the underground mine, and on similar carbon monoxide (CO, another DE component) concentrations] and to surface jobs (based on the use of, or proximity to, diesel-powered equipment). Time trends in air concentrations for underground jobs were estimated from mining facility-specific prediction models using diesel equipment horsepower, total air flow rates exhausted from the underground mines, and, because there were no historical REC measurements, historical measurements of CO. Exposures to potentially confounding agents, i.e. respirable dust, silica, radon, asbestos, and non-diesel sources of polycyclic aromatic hydrocarbons, also were assessed. Accuracy and reliability of the estimated REC exposures levels were evaluated by comparison with several smaller datasets and by development of alternative time trend models. During 1998-2001, the average measured REC exposure level by facility ranged from 40 to 384 μg m⁻³ for the underground workers and from 2 to 6 μg m⁻³ for the surface workers. For one prevalent underground job, 'miner operator', the maximum annual REC exposure estimate by facility ranged up to 685% greater than the corresponding 1998-2001 value. A comparison of the historical CO estimates from the time trend models with 1976-1977 CO measurements not used in the modeling found an overall median relative difference of 29%. Other comparisons showed similar levels of agreement. The assessment process indicated large differences in REC exposure levels over time and across the underground operations. Method evaluations indicated that the final estimates were consistent with those from alternative time trend models and demonstrated moderate to high agreement with external data.

Occupational Exposure to Diesel Particulate Matter in Municipal Household Waste Workers.

PubMed

Lee, Kyong-Hui; Jung, Hye-Jung; Park, Dong-Uk; Ryu, Seung-Hun; Kim, Boowook; Ha, Kwon-Chul; Kim, Seungwon; Yi, Gwangyong; Yoon, Chungsik

2015-01-01

The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM. A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM. The geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 μg/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure. We assessed MHW workers' exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure.

Occupational Exposure to Diesel Particulate Matter in Municipal Household Waste Workers

PubMed Central

Lee, Kyong-Hui; Jung, Hye-Jung; Park, Dong-Uk; Ryu, Seung-Hun; Kim, Boowook; Ha, Kwon-Chul; Kim, Seungwon; Yi, Gwangyong; Yoon, Chungsik

2015-01-01

Objective The purposes of this study were to determine the following: 1) the exposure levels of municipal household waste (MHW) workers to diesel particulate matter (DPM) using elemental carbon (EC), organic carbon (OC), total carbon (TC), black carbon (BC), and fine particulate matter (PM 2.5) as indicators; 2) the correlations among the indicators; 3) the optimal indicator for DPM; and 4) factors that influence personal exposure to DPM. Methods A total of 72 workers in five MHW collection companies were assessed over a period of 7 days from June to September 2014. Respirable EC/OC samples were quantified using the thermal optical transmittance method. BC and PM 2.5 were measured using real-time monitors, an aethalometer and a laser photometer. All results were statistically analyzed for occupational and environmental variables to identify the exposure determinants of DPM. Results The geometric mean of EC, OC, TC, BC and PM 2.5 concentrations were 4.8, 39.6, 44.8, 9.1 and 62.0 μg/m3, respectively. EC concentrations were significantly correlated with the concentrations of OC, TC and BC, but not with those of PM 2.5. The exposures of the MHW collectors to EC, OC, and TC were higher than those of the drivers (p<0.05). Workers of trucks meeting Euro 3 emission standard had higher exposures to EC, OC, TC and PM 2.5 than those working on Euro 4 trucks (p<0.05). Multiple regression analysis revealed that the job task, European engine emission standard, and average driving speed were the most influential factors in determining worker exposure. Conclusions We assessed MHW workers’ exposure to DPM using parallel sampling of five possible indicators. Of these five indicators, EC was shown to be the most useful indicator of DPM exposure for MHW workers, and the job task, European emission standard, and average driving speed were the main determinants of EC exposure. PMID:26248196

Digit-Length Ratios (2D:4D) as a Phenotypic Indicator of in Utero Androgen Exposure is Not Prognostic for Androgenic Alopecia: a Descriptive-Analytic Study of 1200 Iranian Men.

PubMed

Feily, Amir; Hosseinpoor, Masoomeh; Bakhti, Ali; Nekuyi, Mohamad; Sobhanian, Saeed; Fathinezhad, Zahra; Sahraei, Reza; Ramirez-Fort, Marigdalia K

2016-06-15

The etiology of androgenic alopecia (AGA) involves several factors, including genetics, androgens, age and nutrition. Digit-length ratio of the index and ring finger (2D:4D) is an indicator of prenatal exposure to sex hormones. There is a paucity of studies that systemically review the possible positive predictive value of 2D:4D in the development of AGA. We performed a single-site, descriptive-analytical study among a racially homogeneous population. Our results revealed that no significant association was determined between right 2D:4D and AGA severity within our entire population (P=0.384, r=0.025), however a positive correlation coefficient was identified in subjects above the age of 40. Based on the receiver operating characteristic curve analysis, 2D:4D does not predict the development of AGA. AGA is truly a multifactorial disease. Further, our findings suggest that increased in utero exposure to androgens as a fetus does not predispose men to develop AGA.

Personal exposure monitoring of PM2.5 in indoor and outdoor microenvironments.

PubMed

Steinle, Susanne; Reis, Stefan; Sabel, Clive E; Semple, Sean; Twigg, Marsailidh M; Braban, Christine F; Leeson, Sarah R; Heal, Mathew R; Harrison, David; Lin, Chun; Wu, Hao

2015-03-01

Adverse health effects from exposure to air pollution are a global challenge and of widespread concern. Recent high ambient concentration episodes of air pollutants in European cities highlighted the dynamic nature of human exposure and the gaps in data and knowledge about exposure patterns. In order to support health impact assessment it is essential to develop a better understanding of individual exposure pathways in people's everyday lives by taking account of all environments in which people spend time. Here we describe the development, validation and results of an exposure method applied in a study conducted in Scotland. A low-cost particle counter based on light-scattering technology - the Dylos 1700 was used. Its performance was validated in comparison with equivalent instruments (TEOM-FDMS) at two national monitoring network sites (R(2)=0.9 at a rural background site, R(2)=0.7 at an urban background site). This validation also provided two functions to convert measured PNCs into calculated particle mass concentrations for direct comparison of concentrations with equivalent monitoring instruments and air quality limit values. This study also used contextual and time-based activity data to define six microenvironments (MEs) to assess everyday exposure of individuals to short-term PM2.5 concentrations. The Dylos was combined with a GPS receiver to track movement and exposure of individuals across the MEs. Seventeen volunteers collected 35 profiles. Profiles may have a different overall duration and structure with respect to times spent in different MEs and activities undertaken. Results indicate that due to the substantial variability across and between MEs, it is essential to measure near-complete exposure pathways to allow for a comprehensive assessment of the exposure risk a person encounters on a daily basis. Taking into account the information gained through personal exposure measurements, this work demonstrates the added value of data generated by the application of low-cost monitors. Copyright © 2014. Published by Elsevier B.V.

An instantaneous spatiotemporal model to predict a bicyclist's Black Carbon exposure based on mobile noise measurements

NASA Astrophysics Data System (ADS)

Dekoninck, Luc; Botteldooren, Dick; Int Panis, Luc

2013-11-01

Several studies have shown that a significant amount of daily air pollution exposure, in particular Black Carbon (BC), is inhaled during trips. Assessing this contribution to exposure remains difficult because on the one hand local air pollution maps lack spatio-temporal resolution, at the other hand direct measurement of particulate matter concentration remains expensive. This paper proposes to use in-traffic noise measurements in combination with geographical and meteorological information for predicting BC exposure during commuting trips. Mobile noise measurements are cheaper and easier to perform than mobile air pollution measurements and can easily be used in participatory sensing campaigns. The uniqueness of the proposed model lies in the choice of noise indicators that goes beyond the traditional overall A-weighted noise level used in previous work. Noise and BC exposures are both related to the traffic intensity but also to traffic speed and traffic dynamics. Inspired by theoretical knowledge on the emission of noise and BC, the low frequency engine related noise and the difference between high frequency and low frequency noise that indicates the traffic speed, are introduced in the model. In addition, it is shown that splitting BC in a local and a background component significantly improves the model. The coefficients of the proposed model are extracted from 200 commuter bicycle trips. The predicted average exposure over a single trip correlates with measurements with a Pearson coefficient of 0.78 using only four parameters: the low frequency noise level, wind speed, the difference between high and low frequency noise and a street canyon index expressing local air pollution dispersion properties.

External radiation dose and cancer mortality among French nuclear workers: considering potential confounding by internal radiation exposure.

PubMed

Fournier, L; Laurent, O; Samson, E; Caër-Lorho, S; Laroche, P; Le Guen, B; Laurier, D; Leuraud, K

2016-11-01

French nuclear workers have detailed records of their occupational exposure to external radiation that have been used to examine associations with subsequent cancer mortality. However, some workers were also exposed to internal contamination by radionuclides. This study aims to assess the potential for bias due to confounding by internal contamination of estimates of associations between external radiation exposure and cancer mortality. A cohort of 59,004 workers employed for at least 1 year between 1950 and 1994 by CEA (Commissariat à l'Energie Atomique), AREVA NC, or EDF (Electricité de France) and badge-monitored for external radiation exposure were followed through 2004 to assess vital status and cause of death. A flag based on a workstation-exposure matrix defined four levels of potential for internal contamination. Standardized mortality ratios were assessed for each level of the internal contamination indicator. Poisson regression was used to quantify associations between external radiation exposure and cancer mortality, adjusting for potential internal contamination. For solid cancer, the mortality deficit tended to decrease as the levels of potential for internal contamination increased. For solid cancer and leukemia excluding chronic lymphocytic leukemia, adjusting the dose-response analysis on the internal contamination indicator did not markedly change the excess relative risk per Sievert of external radiation dose. This study suggests that in this cohort, neglecting information on internal dosimetry while studying the association between external dose and cancer mortality does not generate a substantial bias. To investigate more specifically the health effects of internal contamination, an effort is underway to estimate organ doses due to internal contamination.

Comparative systems toxicology analysis of cigarette smoke and aerosol from a candidate modified risk tobacco product in organotypic human gingival epithelial cultures: A 3-day repeated exposure study.

PubMed

Zanetti, Filippo; Titz, Bjoern; Sewer, Alain; Lo Sasso, Giuseppe; Scotti, Elena; Schlage, Walter K; Mathis, Carole; Leroy, Patrice; Majeed, Shoaib; Torres, Laura Ortega; Keppler, Brian R; Elamin, Ashraf; Trivedi, Keyur; Guedj, Emmanuel; Martin, Florian; Frentzel, Stefan; Ivanov, Nikolai V; Peitsch, Manuel C; Hoeng, Julia

2017-03-01

Smoking is one of the major lifestyle-related risk factors for periodontal diseases. Modified risk tobacco products (MRTP) offer a promising alternative in the harm reduction strategy for adult smokers unable to quit. Using a systems toxicology approach, we investigated and compared the exposure effects of a reference cigarette (3R4F) and a heat-not-burn technology-based candidate MRTP, the Tobacco Heating System (THS) 2.2. Human gingival epithelial organotypic cultures were repeatedly exposed (3 days) for 28 min at two matching concentrations of cigarette smoke (CS) or THS2.2 aerosol. Results showed only minor histopathological alterations and minimal cytotoxicity upon THS2.2 aerosol exposure compared to CS (1% for THS2.2 aerosol vs. 30% for CS, at the high concentration). Among the 14 proinflammatory mediators analyzed, only 5 exhibited significant alterations with THS2.2 exposure compared with 11 upon CS exposure. Transcriptomic and metabolomic analysis indicated a general reduction of the impact in THS2.2 aerosol-exposed samples with respect to CS (∼79% lower biological impact for the high THS2.2 aerosol concentration compared to CS, and 13 metabolites significantly perturbed for THS2.2 vs. 181 for CS). This study indicates that exposure to THS2.2 aerosol had a lower impact on the pathophysiology of human gingival organotypic cultures than CS. Copyright © 2017 The Authors. Published by Elsevier Ltd.. All rights reserved.

Exposure to traffic pollution, acute inflammation and autonomic response in a panel of car commuters.

PubMed

Sarnat, Jeremy A; Golan, Rachel; Greenwald, Roby; Raysoni, Amit U; Kewada, Priya; Winquist, Andrea; Sarnat, Stefanie E; Dana Flanders, W; Mirabelli, Maria C; Zora, Jennifer E; Bergin, Michael H; Yip, Fuyuen

2014-08-01

Exposure to traffic pollution has been linked to numerous adverse health endpoints. Despite this, limited data examining traffic exposures during realistic commutes and acute response exists. We conducted the Atlanta Commuters Exposures (ACE-1) Study, an extensive panel-based exposure and health study, to measure chemically-resolved in-vehicle exposures and corresponding changes in acute oxidative stress, lipid peroxidation, pulmonary and systemic inflammation and autonomic response. We recruited 42 adults (21 with and 21 without asthma) to conduct two 2-h scripted highway commutes during morning rush hour in the metropolitan Atlanta area. A suite of in-vehicle particulate components were measured in the subjects' private vehicles. Biomarker measurements were conducted before, during, and immediately after the commutes and in 3 hourly intervals after commutes. At measurement time points within 3h after the commute, we observed mild to pronounced elevations relative to baseline in exhaled nitric oxide, C-reactive-protein, and exhaled malondialdehyde, indicative of pulmonary and systemic inflammation and oxidative stress initiation, as well as decreases relative to baseline levels in the time-domain heart-rate variability parameters, SDNN and rMSSD, indicative of autonomic dysfunction. We did not observe any detectable changes in lung function measurements (FEV1, FVC), the frequency-domain heart-rate variability parameter or other systemic biomarkers of vascular injury. Water soluble organic carbon was associated with changes in eNO at all post-commute time-points (p<0.0001). Our results point to measureable changes in pulmonary and autonomic biomarkers following a scripted 2-h highway commute. Copyright © 2014 Elsevier Inc. All rights reserved.

Exposure to traffic pollution, acute inflammation and autonomic response in a panel of car commuters

PubMed Central

Sarnat, Jeremy A.; Golan, Rachel; Greenwald, Roby; Raysoni, Amit U.; Kewada, Priya; Winquist, Andrea; Sarnat, Stefanie E.; Flanders, W. Dana; Mirabelli, Maria C.; Zora, Jennifer E.; Bergin, Michael H.; Yip, Fuyuen

2015-01-01

Background Exposure to traffic pollution has been linked to numerous adverse health endpoints. Despite this, limited data examining traffic exposures during realistic commutes and acute response exists. Objectives: We conducted the Atlanta Commuters Exposures (ACE-1) Study, an extensive panel-based exposure and health study, to measure chemically-resolved in-vehicle exposures and corresponding changes in acute oxidative stress, lipid peroxidation, pulmonary and systemic inflammation and autonomic response. Methods We recruited 42 adults (21 with and 21 without asthma) to conduct two 2-h scripted highway commutes during morning rush hour in the metropolitan Atlanta area. A suite of in-vehicle particulate components were measured in the subjects’ private vehicles. Biomarker measurements were conducted before, during, and immediately after the commutes and in 3 hourly intervals after commutes. Results At measurement time points within 3 h after the commute, we observed mild to pronounced elevations relative to baseline in exhaled nitric oxide, C-reactive-protein, and exhaled malondialdehyde, indicative of pulmonary and systemic inflammation and oxidative stress initiation, as well as decreases relative to baseline levels in the time-domain heart-rate variability parameters, SDNN and rMSSD, indicative of autonomic dysfunction. We did not observe any detectable changes in lung function measurements (FEV1, FVC), the frequency-domain heart-rate variability parameter or other systemic biomarkers of vascular injury. Water soluble organic carbon was associated with changes in eNO at all post-commute time-points (p < 0.0001). Conclusions Our results point to measureable changes in pulmonary and autonomic biomarkers following a scripted 2-h highway commute. PMID:24906070

Demographic responses to multi-generation cadmium exposure in two strains of the freshwater gastropod, Biomphalaria glabrata.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Salice, Christopher J.; Miller, Thomas J.; Roesijadi, Guritno

2008-08-20

A life table response experiment (LTRE) was used to quantify the population-level effects of continuous, multi-generation cadmium exposure on two strains of the freshwater gastropod, Biomphalaria glabrata; the parasite resistant BS90 and parasite susceptible NMRI strains. Snails were exposed to waterborne cadmium for three consecutive generations. Survival, growth and reproduction were measured empirically and incorporated into a stage-based, deterministic population model. Cadmium significantly affected hatching success, time to maturity and juvenile and adult survival in both strains. There were significant effects of generation on fecundity, hatching success time to maturity and juvenile survival in NMRI and time to maturity andmore » adult survival in BS90. Cadmium significantly affected the population growth rate, lambda (λ), in BS90. Cadmium, generation and the cadmium x generation interaction had significant effects on λ in NMRI. At the high cadmium exposure, λ for NMRI showed a decrease from generation 1 to generation 2 followed by and increase from generation 2 to 3. Lambda in high cadmium BS90 steadily decreased over the three generations while NMRI at this same concentration was similar to the controls. The results indicated that strain-specific differences in response to multi-generation cadmium exposure are evident in B. glabrata. Moreover, effects seen in the first generation are not necessarily indicative of effects in subsequent generations. Changes in λ over the course of the three-generation exposure suggest that acclimation and/or adaptation to cadmium may have occurred, particularly in NMRI at the high cadmium exposure level.« less

Medical and non-medical protection standards for ultrasound and infrasound.

PubMed

Duck, Francis A

2007-01-01

Protection from inappropriate or hazardous exposure to ultrasound is controlled through international standards and national regulations. IEC standard 60601 part 1 establishes requirements for the mechanical, electrical, chemical and thermal safety for all electro-medical equipment. The associated part 2 standard for diagnostic medical ultrasonic equipment sets no upper limits on ultrasonic exposure. Instead, safety indices are defined that are intended to advise users on the degree of thermal and mechanical hazard. At present the display of these safety indices satisfies regulatory requirements in both the USA and Europe. Nevertheless there are reservations about the effectiveness of this approach to protection management. In the USA, there are national regulatory limits on diagnostic exposure, based on acoustic output from clinical equipment in use over 20 years ago. The IEC 60601 part 2 standard for therapeutic equipment sets 3 W cm(-2) as the limit on acoustic intensity. Transducer surface temperature is controlled for both diagnostic and therapy devices. For airborne ultrasound, interim guidelines on limits of human exposure published by the IRPA are now 2 decades old. A limit on sound pressure level of 100 dB for the general population is recommended. The absence of protection standards for infrasound relates to difficulties in measurement at these low frequencies.

Is sports choice and participation related to 2D:4D? A study among adult male students in Wrocław, Poland.

PubMed

Koziel, Slawomir; Kociuba, Marek; Ignasiak, Zofia; Chakraborty, Raja

2016-06-01

Psychology and personality of individuals may have implications for choice of, and performance in sports disciplines. Individual- and group sports differ in psychological requirements, such as, competitiveness, sensation seeking and risk taking attitude, often required in sports. There is sex difference in human in these qualities, which also show association with prenatal testosterone exposures. Second-to-fourth digit lengths ratio (2D:4D) is an indicator of prenatal testosterone exposure. Lower 2D:4D indicates higher prenatal testosteron exposure and vice versa. Males generally have lower 2D:4D than females. This study cross-sectional study investigated the relationship of 2D:4D with team based- or individual sports. The participants were 421 Polish male students with a mean (+SD) age of 19.78 (+0.79) years. Among them, 139 were engaged in sports and 282 were not. Mean 2D:4D in each hand of individual sporting group was significantly lower than the team sports- and no sports groups. Participants not involved in any sports had the highest mean 2D:4D value. However, the team sportsmen’s 2D:4D did not differ from the non sporting group. Prenatal testosterone exposure might have implication in sports choice and participation.

Occupational risk factors have to be considered in the definition of high-risk lung cancer populations.

PubMed

Wild, P; Gonzalez, M; Bourgkard, E; Courouble, N; Clément-Duchêne, C; Martinet, Y; Févotte, J; Paris, C

2012-03-27

The aim of this study was to compute attributable fractions (AF) to occupational factors in an area in North-Eastern France with high lung cancer rates and a past of mining and steel industry. A population-based case-control study among males aged 40-79 was conducted, including confirmed primary lung cancer cases from all hospitals of the study region. Controls were stratified by broad age-classes, district and socioeconomic classes. Detailed occupational and personal risk factors were obtained in face-to-face interviews. Cumulative occupational exposure indices were obtained from the questionnaires. Attributable fractions were computed from multiple unconditional logistic regression models. A total of 246 cases and 531 controls were included. The odds ratios (ORs) adjusted on cumulative smoking and family history of lung cancer increased significantly with the cumulative exposure indices to asbestos, polycyclic aromatic hydrocarbons and crystalline silica, and with exposure to diesel motor exhaust. The AF for occupational factors exceeded 50%, the most important contributor being crystalline silica and asbestos. These AFs are higher than most published figures. This can be because of the highly industrialised area or methods for exposure assessments. Occupational factors are important risk factors and should not be forgotten when defining high-risk lung cancer populations.

The risks and benefits of sun exposure 2016.

PubMed

Hoel, David G; Berwick, Marianne; de Gruijl, Frank R; Holick, Michael F

2016-01-01

Public health authorities in the United States are recommending that men, women and children reduce their exposure to sunlight, based on concerns that this exposure will promote skin cancer. On the other hand, data show that increasing numbers of Americans suffer from vitamin D deficiencies and serious health problems caused by insufficient sun exposure. The body of science concerning the benefits of moderate sun exposure is growing rapidly, and is causing a different perception of sun/UV as it relates to human health. Melanoma and its relationship to sun exposure and sunburn is not adequately addressed in most of the scientific literature. Reports of favorable health outcomes related to adequate serum 25(OH)D concentration or vitamin D supplementation have been inappropriately merged, so that benefits of sun exposure other than production of vitamin D are not adequately described. This review of recent studies and their analyses consider the risks and benefits of sun exposure which indicate that insufficient sun exposure is an emerging public health problem. This review considers the studies that have shown a wide range health benefits from sun/UV exposure. These benefits include among others various types of cancer, cardiovascular disease, Alzheimer disease/dementia, myopia and macular degeneration, diabetes and multiple sclerosis. The message of sun avoidance must be changed to acceptance of non-burning sun exposure sufficient to achieve serum 25(OH)D concentration of 30 ng/mL or higher in the sunny season and the general benefits of UV exposure beyond those of vitamin D.

Biosorption of molybdenum and chromium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pryfogle, P.A.; Maiers, D.T.; Wichlacz, P.L.

1989-01-01

The effects of metal solution concentration, biomass density, length of exposure time, and pH were determined for biosorption of molybdenum (Mo) and chromium (Cr) by three organisms. Results indicate that it is possible to sorb Mo and Cr from dilute solutions. Differences were observed in the abilities of an organism to sorb Mo and Cr as well as among respective abilities of the three microorganisms. This suggests an inherent selectivity of the organism which may afford the selectivity of the organism which may afford the means to control a sorption-based process. Results also indicate that the metal sorption abilities ofmore » these microorganisms depend on duration of exposure, biomass density, solution pH, and the metal concentration of the solution. Each of these parameters suggests an additional means of controlling the sorption process. 20 refs., 6 figs., 3 tabs.« less

Does Fear Reactivity during Exposure Predict Panic Symptom Reduction?

ERIC Educational Resources Information Center

Meuret, Alicia E.; Seidel, Anke; Rosenfield, Benjamin; Hofmann, Stefan G.; Rosenfield, David

2012-01-01

Objective: Fear reactivity during exposure is a commonly used indicator of learning and overall therapy outcome. The objective of this study was to assess the predictive value of fear reactivity during exposure using multimodal indicators and an advanced analytical design. We also investigated the degree to which treatment condition (cognitive…

Epidemiological approaches in the investigation of environmental causes of cancer: the case of dioxins and water disinfection by-products

PubMed Central

2011-01-01

I will refer in this paper to difficulties in research in environmental causes of cancer using as examples research on dioxins and on drinking water disinfection by-products (DBPs) that have created considerable controversy in the scientific and wider community. Dioxins are highly toxic chemicals that are animal carcinogens. For many years, evaluation of the carcinogenicity of dioxins in humans was based on case-control or registry based studies. The development of methods to measure dioxins in blood indicated that these studies suffered from extreme exposure misclassification. The conduct of large cohort studies of workers with widely contrasted exposures together with the use of biomarkers and models for exposure assessment, led to convincing evidence on the carcinogenicity of dioxins in humans. The high toxicity of a few dioxin congeners, the availability of a scheme to characterize the toxicity of a mixture of dioxins and related compounds and the long half-life of these compounds facilitated epidemiological research. Contrary to dioxins, trihalomethanes (THMs) and most of the hundreds of DBPs in drinking water are chemicals of low toxicity. For more than 15 years, the main evidence on the carcinogenicity of DBPs was through ecological or death certificate studies. More recent studies based on individual assessment confirmed increases in bladder cancer risk. However even those studies ignored the toxicological evidence on the importance of routes of exposure to DBPs other than ingestion and, probably, underestimated the risk. Persistence of weak study designs together with delays in advanced exposure assessment models led to delays in confirming early evidence on the carcinogenicity of DBPs. The evaluation of only a few chemicals when exposure is to a complex mixture remains a major problem in exposure assessment for DBPs. The success of epidemiological studies in identifying increased risks lies primarily on the wide contrast of exposure to DBPs in the general population that overcomes the significant exposure misclassification. Exposure assessment has been the Achilles heel for studies on dioxins and DBPs and cancer. The combination of powerful study designs, advanced exposure assessment together with a better understanding of mechanisms of disease and the use of biomarkers of exposure, led to the strengthening of the epidemiological evidence. PMID:21489213

Inhalation toxicity of indoor air pollutants in Drosophila melanogaster using integrated transcriptomics and computational behavior analyses

NASA Astrophysics Data System (ADS)

Eom, Hyun-Jeong; Liu, Yuedan; Kwak, Gyu-Suk; Heo, Muyoung; Song, Kyung Seuk; Chung, Yun Doo; Chon, Tae-Soo; Choi, Jinhee

2017-06-01

We conducted an inhalation toxicity test on the alternative animal model, Drosophila melanogaster, to investigate potential hazards of indoor air pollution. The inhalation toxicity of toluene and formaldehyde was investigated using comprehensive transcriptomics and computational behavior analyses. The ingenuity pathway analysis (IPA) based on microarray data suggests the involvement of pathways related to immune response, stress response, and metabolism in formaldehyde and toluene exposure based on hub molecules. We conducted a toxicity test using mutants of the representative genes in these pathways to explore the toxicological consequences of alterations of these pathways. Furthermore, extensive computational behavior analysis showed that exposure to either toluene or formaldehyde reduced most of the behavioral parameters of both wild-type and mutants. Interestingly, behavioral alteration caused by toluene or formaldehyde exposure was most severe in the p38b mutant, suggesting that the defects in the p38 pathway underlie behavioral alteration. Overall, the results indicate that exposure to toluene and formaldehyde via inhalation causes severe toxicity in Drosophila, by inducing significant alterations in gene expression and behavior, suggesting that Drosophila can be used as a potential alternative model in inhalation toxicity screening.

Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas

USGS Publications Warehouse

Mahler, Barbara J.; Ingersoll, Christopher G.; Van Metre, Peter C.; Kunz, James L.; Little, Edward E.

2015-01-01

Runoff from coal-tar-based (CT) sealcoated pavement is a source of polycyclic aromatic hydrocarbons (PAHs) and N-heterocycles to surface waters. We investigated acute toxicity of simulated runoff collected from 5 h to 111 days after application of CT sealcoat and from 4 h to 36 days after application of asphalt-based sealcoat containing about 7% CT sealcoat (AS/CT-blend). Ceriodaphnia dubia (cladocerans) and Pimephales promelas (fathead minnows) were exposed in the laboratory to undiluted and 1:10 diluted runoff for 48 h, then transferred to control water and exposed to 4 h of ultraviolet radiation (UVR). Mortality following exposure to undiluted runoff from unsealed asphalt pavement and UVR was ≤10% in all treatments. Test organisms exposed to undiluted CT runoff samples collected during the 3 days (C. dubia) or 36 days (P. promelas) following sealcoat application experienced 100% mortality prior to UVR exposure; with UVR exposure, mortality was 100% for runoff collected across the entire sampling period. Phototoxic-equivalent PAH concentrations and mortality demonstrated an exposure-response relation. The results indicate that runoff remains acutely toxic for weeks to months after CT sealcoat application.

Acute toxicity of runoff from sealcoated pavement to Ceriodaphnia dubia and Pimephales promelas.

PubMed

Mahler, Barbara J; Ingersoll, Christopher G; Van Metre, Peter C; Kunz, James L; Little, Edward E

2015-04-21

Runoff from coal-tar-based (CT) sealcoated pavement is a source of polycyclic aromatic hydrocarbons (PAHs) and N-heterocycles to surface waters. We investigated acute toxicity of simulated runoff collected from 5 h to 111 days after application of CT sealcoat and from 4 h to 36 days after application of asphalt-based sealcoat containing about 7% CT sealcoat (AS/CT-blend). Ceriodaphnia dubia (cladocerans) and Pimephales promelas (fathead minnows) were exposed in the laboratory to undiluted and 1:10 diluted runoff for 48 h, then transferred to control water and exposed to 4 h of ultraviolet radiation (UVR). Mortality following exposure to undiluted runoff from unsealed asphalt pavement and UVR was ≤10% in all treatments. Test organisms exposed to undiluted CT runoff samples collected during the 3 days (C. dubia) or 36 days (P. promelas) following sealcoat application experienced 100% mortality prior to UVR exposure; with UVR exposure, mortality was 100% for runoff collected across the entire sampling period. Phototoxic-equivalent PAH concentrations and mortality demonstrated an exposure-response relation. The results indicate that runoff remains acutely toxic for weeks to months after CT sealcoat application.

Inhalation toxicity of indoor air pollutants in Drosophila melanogaster using integrated transcriptomics and computational behavior analyses

PubMed Central

Eom, Hyun-Jeong; Liu, Yuedan; Kwak, Gyu-Suk; Heo, Muyoung; Song, Kyung Seuk; Chung, Yun Doo; Chon, Tae-Soo; Choi, Jinhee

2017-01-01

We conducted an inhalation toxicity test on the alternative animal model, Drosophila melanogaster, to investigate potential hazards of indoor air pollution. The inhalation toxicity of toluene and formaldehyde was investigated using comprehensive transcriptomics and computational behavior analyses. The ingenuity pathway analysis (IPA) based on microarray data suggests the involvement of pathways related to immune response, stress response, and metabolism in formaldehyde and toluene exposure based on hub molecules. We conducted a toxicity test using mutants of the representative genes in these pathways to explore the toxicological consequences of alterations of these pathways. Furthermore, extensive computational behavior analysis showed that exposure to either toluene or formaldehyde reduced most of the behavioral parameters of both wild-type and mutants. Interestingly, behavioral alteration caused by toluene or formaldehyde exposure was most severe in the p38b mutant, suggesting that the defects in the p38 pathway underlie behavioral alteration. Overall, the results indicate that exposure to toluene and formaldehyde via inhalation causes severe toxicity in Drosophila, by inducing significant alterations in gene expression and behavior, suggesting that Drosophila can be used as a potential alternative model in inhalation toxicity screening. PMID:28621308

Workplace bullying and subsequent health problems.

PubMed

Nielsen, Morten Birkeland; Magerøy, Nils; Gjerstad, Johannes; Einarsen, Ståle

2014-07-01

Cross-sectional studies demonstrate that exposure to bullying in the workplace is positively correlated with self-reported health problems. However, these studies do not provide a basis to draw conclusions on the extent to which bullying leads to increased health problems or whether health problems increase the risk of being bullied. To provide better indications of a causal relationship, knowledge from prospective studies on the association between bullying in the workplace and health outcomes is therefore summarised. We conducted a systematic literature review of original articles from central literature databases on longitudinal associations between bullying in the workplace and health. Average associations between bullying and health outcomes are calculated using meta-analysis. A consistent finding across the studies is that exposure to bullying is significantly positively related to mental health problems (OR =1.68; 95% KI 1.35-2.09) and somatic symptoms (OR = 1.77; 95% KI 1.41-2.22) over time. Mental health problems are also associated with subsequent exposure to bullying (OR = 1.74; 95% KI 1.44-2.12). Bullying is positively related to mental health problems and somatic symptoms. The association between mental health problems and subsequent bullying indicates a self-reinforcing process between mental health and bullying. The methodological quality of the studies that were conducted is relatively sound. However, based on the existing knowledge base there are no grounds for conclusions regarding an unambiguous causal relationship between bullying and health.

Night-shift work and breast cancer risk in a cohort of Chinese women.

PubMed

Pronk, Anjoeka; Ji, Bu-Tian; Shu, Xiao-Ou; Xue, Shouzheng; Yang, Gong; Li, Hong-Lan; Rothman, Nathaniel; Gao, Yu-Tang; Zheng, Wei; Chow, Wong-Ho

2010-05-01

Shift work involving disruption of circadian rhythms has been classified as a probable cause of human cancer by the International Agency for Research on Cancer, based on limited epidemiologic evidence and abundant experimental evidence. The authors investigated this association in a population-based prospective cohort study of Chinese women. At baseline (1996-2000), information on lifetime occupational history was obtained from 73,049 women. Lifetime night-shift exposure indices were created using a job exposure matrix. During 2002-2004, self-reported data on frequency and duration of night-shift work were collected. Hazard ratios and 95% confidence intervals, adjusted for major breast cancer risk factors, were calculated. During follow-up through 2007, 717 incident cases of breast cancer were diagnosed. Breast cancer risk was not associated with ever working the night shift on the basis of the job exposure matrix (adjusted hazard ratio = 1.0, 95% confidence interval: 0.9, 1.2) or self-reported history of night-shift work (adjusted hazard ratio = 0.9, 95% confidence interval: 0.7, 1.1). Risk was also not associated with frequency, duration, or cumulative amount of night-shift work. There were no indications of effect modification. The lack of an association between night-shift work and breast cancer adds to the inconsistent epidemiologic evidence. It may be premature to consider shift work a cause of cancer.

The SED-TOX: Toxicity-directed management tool to assess and rank sediments based on their hazard -- concept and application

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bombardier, M.; Bermingham, N.

1999-04-01

This article introduces the sediment Toxicity (SED-TOX) Index for the assessment and ranking of toxic hazards in sediment. Major features include expression of toxicity responses on a single scale of measurement (dry weight-based toxic units), consideration of multiple routes of exposure (pore water, organic extract, wet sediment, and whole sediment), application of differential treatments to toxicity data depending on the level of response, and use of weighting factors to discriminate sediment exposure phases and effect endpoints on the basis of sensitivity. A battery of seven bioassays with four test species (Vibrio fischeri, Escherichia coli, Lytechinus pictus, and Amphiporeia virginiana) wasmore » conducted on 49 marine sediment samples collected from six sites at Anse-a-Beaufils and Cap-aux-Meules, which are in the Gulf of St. Lawrence. The SED-TOX scores were calculated for each sampling station and compared with sediment contaminant concentrations. Results indicate that physico-chemical characterization is not sufficient to assess contaminated-sediment hazard for organisms; furthermore, using several exposure phases and test species belonging to various trophic levels increases the possibility of correctly identifying toxic sediments. The results of this study indicate that the SED-TOX approach is valuable as a toxicity assessment and ranking tool for sediments. It could easily be combined with other measures of ecosystem disturbance to discriminate between polluted and unpolluted sites.« less

A flux-based assessment of above and below ground biomass of Holm oak (Quercus ilex L.) seedlings after one season of exposure to high ozone concentrations

NASA Astrophysics Data System (ADS)

Gerosa, Giacomo; Fusaro, Lina; Monga, Robert; Finco, Angelo; Fares, Silvano; Manes, Fausto; Marzuoli, Riccardo

2015-07-01

Young plants of Holm oak (Quercus ilex) were exposed in non-limiting water conditions to four different levels of ozone (O3) concentrations in Open-Top Chambers during one growing season to evaluate biomass losses on roots, stems and leaves in relation to O3 exposure (AOT40) and phytotoxical ozone dose (POD1) absorbed. The exposure-effect and dose-effect relationships for the total biomass were statistically significant and indicated a reduction of 4% and 5.2% of the total biomass for each increase step of 10000 ppb h of AOT40 and 10 mmol m-2 of POD1, respectively. The results indicate a critical level for Holm oak protection of 7 mmol m-2 of POD1, which corresponds to 4% of total biomass reduction. The linear regressions based on the POD1 were significant for roots and stem biomass losses, but not significant for leaf biomass. The biomass loss rate at increasing POD1 was higher for roots than for stems and leaves, suggesting that stem growth under high levels of O3 is less affected than root growth. Because of the scarcity of data from the Mediterranean area, these results can be relevant for the O3 risk assessment models and for the definition of new O3 critical levels for forests in Europe.

Impacts of Perinatal Dioxin Exposure on Motor Coordination and Higher Cognitive Development in Vietnamese Preschool Children: A Five-Year Follow-Up

PubMed Central

Tran, Nghi Ngoc; Pham, Tai The; Ozawa, Kyoko; Nishijo, Muneko; Nguyen, Anh Thi Nguyet; Tran, Tuong Quy; Hoang, Luong Van; Tran, Anh Hai; Phan, Vu Huy Anh; Nakai, Akio; Nishino, Yoshikazu; Nishijo, Hisao

2016-01-01

Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder. PMID:26824471

Impacts of Perinatal Dioxin Exposure on Motor Coordination and Higher Cognitive Development in Vietnamese Preschool Children: A Five-Year Follow-Up.

PubMed

Tran, Nghi Ngoc; Pham, Tai The; Ozawa, Kyoko; Nishijo, Muneko; Nguyen, Anh Thi Nguyet; Tran, Tuong Quy; Hoang, Luong Van; Tran, Anh Hai; Phan, Vu Huy Anh; Nakai, Akio; Nishino, Yoshikazu; Nishijo, Hisao

2016-01-01

Dioxin concentrations remain elevated in the environment and in humans residing near former US Air Force bases in South Vietnam. Our previous epidemiological studies showed adverse effects of dioxin exposure on neurodevelopment for the first 3 years of life. Subsequently, we extended the follow-up period and investigated the influence of perinatal dioxin exposure on neurodevelopment, including motor coordination and higher cognitive ability, in preschool children. Presently, we investigated 176 children in a hot spot of dioxin contamination who were followed up from birth until 5 years old. Perinatal dioxin exposure levels were estimated by measuring dioxin levels in maternal breast milk. Dioxin toxicity was evaluated using two indices; toxic equivalent (TEQ)-polychlorinated dibenzo-p-dioxins/furans (PCDDs/Fs) and concentration of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). Coordinated movements, including manual dexterity, aiming and catching, and balance, were assessed using the Movement Assessment Battery for Children, Second Edition (Movement ABC-2). Cognitive ability was assessed using the nonverbal index (NVI) of the Kaufman Assessment Battery for Children, Second Edition (KABC-II). In boys, total test and balance scores of Movement ABC-2 were significantly lower in the high TEQ- PCDDs/Fs group compared with the moderate and low exposure groups. NVI scores and the pattern reasoning subscale of the KABC-II indicating planning ability were also significantly lower in the high TCDD exposure group compared with the low exposure group of boys. However, in girls, no significant differences in Movement ABC-2 and KABC-II scores were found among the different TEQ-PCDDs/Fs and TCDD exposure groups. Furthermore, in high risk cases, five boys and one girl highly exposed to TEQ-PCDDs/Fs and TCDD had double the risk for difficulties in both neurodevelopmental skills. These results suggest differential impacts of TEQ-PCDDs/Fs and TCDD exposure on motor coordination and higher cognitive ability, respectively. Moreover, high TEQ-PCDDs/Fs exposure combined with high TCDD exposure may increase autistic traits combined with developmental coordination disorder.

Median infectious dose (ID₅₀) of porcine reproductive and respiratory syndrome virus isolate MN-184 via aerosol exposure.

PubMed

Cutler, Timothy D; Wang, Chong; Hoff, Steven J; Kittawornrat, Apisit; Zimmerman, Jeffrey J

2011-08-05

The median infectious dose (ID(50)) of porcine reproductive and respiratory syndrome (PRRS) virus isolate MN-184 was determined for aerosol exposure. In 7 replicates, 3-week-old pigs (n=58) respired 10l of airborne PRRS virus from a dynamic aerosol toroid (DAT) maintained at -4°C. Thereafter, pigs were housed in isolation and monitored for evidence of infection. Infection occurred at virus concentrations too low to quantify by microinfectivity assays. Therefore, exposure dose was determined using two indirect methods ("calculated" and "theoretical"). "Calculated" virus dose was derived from the concentration of rhodamine B monitored over the exposure sequence. "Theoretical" virus dose was based on the continuous stirred-tank reactor model. The ID(50) estimate was modeled on the proportion of pigs that became infected using the probit and logit link functions for both "calculated" and "theoretical" exposure doses. Based on "calculated" doses, the probit and logit ID(50) estimates were 1 × 10(-0.13)TCID(50) and 1 × 10(-0.14)TCID(50), respectively. Based on "theoretical" doses, the probit and logit ID(50) were 1 × 10(0.26)TCID(50) and 1 × 10(0.24)TCID(50), respectively. For each point estimate, the 95% confidence interval included the other three point estimates. The results indicated that MN-184 was far more infectious than PRRS virus isolate VR-2332, the only other PRRS virus isolate for which ID(50) has been estimated for airborne exposure. Since aerosol ID(50) estimates are available for only these two isolates, it is uncertain whether one or both of these isolates represent the normal range of PRRS virus infectivity by this route. Copyright © 2011 Elsevier B.V. All rights reserved.

Cosmogenic 10Be and 26Al exposure ages of tors and erratics, Cairngorm Mountains, Scotland: Timescales for the development of a classic landscape of selective linear glacial erosion

USGS Publications Warehouse

Phillips, W.M.; Hall, A.M.; Mottram, R.; Fifield, L.K.; Sugden, D.E.

2006-01-01

The occurrence of tors within glaciated regions has been widely cited as evidence for the preservation of relic pre-Quaternary landscapes beneath protective covers of non-erosive dry-based ice. Here, we test for the preservation of pre-Quaternary landscapes with cosmogenic surface exposure dating of tors. Numerous granite tors are present on summit plateaus in the Cairngorm Mountains of Scotland where they were covered by local ice caps many times during the Pleistocene. Cosmogenic 10Be and 26Al data together with geomorphic relationships reveal that these landforms are more dynamic and younger than previously suspected. Many Cairngorm tors have been bulldozed and toppled along horizontal joints by ice motion, leaving event surfaces on tor remnants and erratics that can be dated with cosmogenic nuclides. As the surfaces have been subject to episodic burial by ice, an exposure model based upon ice and marine sediment core proxies for local glacial cover is necessary to interpret the cosmogenic nuclide data. Exposure ages and weathering characteristics of tors are closely correlated. Glacially modified tors and boulder erratics with slightly weathered surfaces have 10Be exposure ages of about 15 to 43 ka. Nuclide inheritance is present in many of these surfaces. Correction for inheritance indicates that the eastern Cairngorms were deglaciated at 15.6 ?? 0.9 ka. Glacially modified tors with moderate to advanced weathering features have 10Be exposure ages of 19 to 92 ka. These surfaces were only slightly modified during the last glacial cycle and gained much of their exposure during the interstadial of marine Oxygen Isotope Stage 5 or earlier. Tors lacking evidence of glacial modification and exhibiting advanced weathering have 10Be exposure ages between 52 and 297 ka. Nuclide concentrations in these surfaces are probably controlled by bedrock erosion rates instead of discrete glacial events. Maximum erosion rates estimated from 10Be range from 2.8 to 12.0 mm/ka, with an error weighted mean of 4.1 ?? 0.2 mm/ka. Three of these surfaces yield model exposure-plus-burial ages of 295-71+84, 520-141+178, and 626-85+102 ka. A vertical cosmogenic nuclide profile across the oldest sampled tor indicates a long-term emergence rate of 31 ?? 2 mm/ka. These findings show that dry-based ice caps are capable of substantially eroding tors by entraining blocks previously detached by weathering processes. Bedrock surfaces and erratic boulders in such settings are likely to have nuclide inheritance and may yield erroneous (too old) exposure ages. While many Cairngorm tors have survived multiple glacial cycles, rates of regolith stripping and bedrock erosion are too high to permit the widespread preservation of pre-Quaternary rock surfaces. ?? 2005 Elsevier B.V. All rights reserved.

Occupational Sunlight Exposure and Risk of Renal Cell Carcinoma

PubMed Central

Karami, Sara; Boffetta, Paolo; Stewart, Patricia; Rothman, Nathaniel; Hunting, Katherine L.; Dosemeci, Mustafa; Berndt, Sonja I.; Brennan, Paul; Chow, Wong-Ho; Moore, Lee E.; Zaridze, David; Mukeria, Anush; Janout, Vladimir; Kollarova, Helena; Bencko, Vladimir; Holcatova, Ivana; Navritalova, Marie; Szeszenia-Dabrowska, Neonila; Mates, Dana; Gromiec, Jan P.

2010-01-01

Background Recent findings indicate that vitamin D obtained from ultraviolet (UV) exposure may reduce the risk of a number of different cancers. Vitamin D is metabolized to its active form within the kidney, the major organ for vitamin D metabolism and activity. Since both the incidence of renal cell cancer and prevalence of vitamin D deficiency have increased over the past few decades, this study sought to explore whether occupational UV exposure was associated with renal cell carcinoma (RCC) risk. Methods A hospital-based case-control study of 1,097 RCC cases and 1,476 controls was conducted in four Central and Eastern European countries. Demographic and occupational information was collected to examine the association between occupational UV exposure and RCC risk. Results A significant (24%-38%) reduction in RCC risk was observed with increasing occupational UV exposure among male participants. No association between UV exposure and RCC risk was observed among female participants. When analyses were stratified by latitude as another estimate of sunlight intensity, a stronger (71%-73%) reduction in RCC risk was observed between UV exposure and cancer risk among males residing at the highest latitudes. Conclusion The results of this study suggest that among males there is an inverse association between occupational UV exposure and renal cancer risk. Replication studies are warranted to confirm these results. PMID:20213683

Effects of radiofrequency radiation emitted by cellular telephones on the cognitive functions of humans.

PubMed

Eliyahu, Ilan; Luria, Roy; Hareuveny, Ronen; Margaliot, Menachem; Meiran, Nachshon; Shani, Gad

2006-02-01

The present study examined the effects of exposure to Electromagnetic Radiation emitted by a standard GSM phone at 890 MHz on human cognitive functions. This study attempted to establish a connection between the exposure of a specific area of the brain and the cognitive functions associated with that area. A total of 36 healthy right-handed male subjects performed four distinct cognitive tasks: spatial item recognition, verbal item recognition, and two spatial compatibility tasks. Tasks were chosen according to the brain side they are assumed to activate. All subjects performed the tasks under three exposure conditions: right side, left side, and sham exposure. The phones were controlled by a base station simulator and operated at their full power. We have recorded the reaction times (RTs) and accuracy of the responses. The experiments consisted of two sections, of 1 h each, with a 5 min break in between. The tasks and the exposure regimes were counterbalanced. The results indicated that the exposure of the left side of the brain slows down the left-hand response time, in the second-later-part of the experiment. This effect was apparent in three of the four tasks, and was highly significant in only one of the tests. The exposure intensity and its duration exceeded the common exposure of cellular phone users.

The toxicity of benzene and its metabolism and molecular pathology in human risk assessment.

PubMed Central

Yardley-Jones, A; Anderson, D; Parke, D V

1991-01-01

Benzene, a common industrial chemical and a component of gasoline, is radiomimetic and exposure may lead progressively to aplastic anaemia, leukaemia, and multiple myeloma. Although benzene has been shown to cause many types of genetic damage, it has consistently been classified as a non-mutagen in the Ames test, possibly because of the inadequacy of the S9 microsomal activation system. The metabolism of benzene is complex, yielding glucuronide and sulphate conjugates of phenol, quinol, and catechol, L-phenylmercapturic acid, and muconaldehyde and trans, trans-muconic acid by ring scission. Quinol is oxidised to p-benzoquinone, which binds to vital cellular components or undergoes redox cycling to generate oxygen radicals; muconaldehyde, like p-benzoquinone, is toxic through depletion of intracellular glutathione. Exposure to benzene may also induce the microsomal mixed function oxidase, cytochrome P450 IIE1, which is probably responsible for the oxygenation of benzene, but also has a propensity to generate oxygen radicals. The radiomimetic nature of benzene and its ability to induce different sites of neoplasia indicate that formation of oxygen radicals is a major cause of benzene toxicity, which involves multiple mechanisms including synergism between arylating and glutathione-depleting reactive metabolites and oxygen radicals. The occupational exposure limit in the United Kingdom (MEL) and the United States (PEL) was 10 ppm based on the association of benzene exposure with aplastic anaemia, but recently was lowered to 5 ppm and 1 ppm respectively, reflecting a concern for the risk of neoplasia. The American Conference of Governmental Industrial Hygienists (ACGIH) has even more recently recommended that, as benzene is considered an A1 carcinogen, the threshold limit value (TLV) should be decreased to 0.1 ppm. Only one study in man, based on nine cases of benzene associated fatal neoplasia, has been considered suitable for risk assessment. Recent re-evaluation of these data indicated that past assessments may have overestimated the risk, and different authors have considered that lifetime exposure to benzene at 1 ppm would result in an excess of leukaemia deaths of 9.5 to 1.0 per 1000. Although in this study, deaths at low levels of benzene exposure were associated with multiple myeloma and a long latency period, instead of leukaemia, which might justify further lowering of the exposure limit, the risk assessment model has been found to be non-significant for response at low levels of exposure. The paucity of data for man, the complexity of the metabolic activation of benzene, the interactive and synergistic mechanisms of benzene toxicity and carcinogenicity, the different disease endpoints (aplastic anaemia, leukaemia, and multiple myeloma), and different individual susceptibilities, all indicate that in such a complex scenario, regulators should proceed with caution before making further changes to the exposure limit for this chemical. PMID:1854646

Cosmogenic exposure age constraints on deglaciation and flow behaviour of a marine-based ice stream in western Scotland, 21-16 ka

NASA Astrophysics Data System (ADS)

Small, David; Benetti, Sara; Dove, Dayton; Ballantyne, Colin K.; Fabel, Derek; Clark, Chris D.; Gheorghiu, Delia M.; Newall, Jennifer; Xu, Sheng

2017-07-01

Understanding how marine-based ice streams operated during episodes of deglaciation requires geochronological data that constrain both timing of deglaciation and changes in their flow behaviour, such as that from unconstrained ice streaming to topographically restricted flow. We present seventeen new 10Be exposure ages from glacial boulders and bedrock at sites in western Scotland within the area drained by the Hebrides Ice Stream, a marine-based ice stream that drained a large proportion of the former British-Irish Ice Sheet. Exposure ages from Tiree constrain deglaciation of a topographic high within the central zone of the ice stream, from which convergent flowsets were produced during ice streaming. These ages thus constrain thinning of the Hebrides Ice Stream, which, on the basis of supporting information, we infer to represent cessation of ice streaming at 20.6 ± 1.2 ka, 3-4 ka earlier than previously inferred. A period of more topographically restricted flow produced flow indicators superimposed on those relating to full ice stream conditions, and exposure ages from up-stream of these constrain deglaciation to 17.5 ± 1.0 ka. Complete deglaciation of the marine sector of the Hebrides Ice Stream occurred by 17-16 ka at which time the ice margin was located near the present coastline. Exposure ages from the southernmost Outer Hebrides (Mingulay and Barra) indicate deglaciation at 18.9 ± 1.0 and 17.1 ± 1.0 ka respectively, demonstrating that an independent ice cap persisted on the southern Outer Hebrides for 3-4 ka after initial ice stream deglaciation. This suggests that deglaciation of the Hebrides Ice Stream was focused along major submarine troughs. Collectively, our data constrain initial deglaciation and changes in flow regime of the Hebrides Ice Stream, final deglaciation of its marine sector, and deglaciation of the southern portion of the independent Outer Hebrides Ice Cap, providing chronological constraints on future numerical reconstructions of this key sector of the former British-Irish Ice Sheet.

Computational Toxicology of Chloroform: Reverse Dosimetry Using Bayesian Inference, Markov Chain Monte Carlo Simulation, and Human Biomonitoring Data

PubMed Central

Lyons, Michael A.; Yang, Raymond S.H.; Mayeno, Arthur N.; Reisfeld, Brad

2008-01-01

Background One problem of interpreting population-based biomonitoring data is the reconstruction of corresponding external exposure in cases where no such data are available. Objectives We demonstrate the use of a computational framework that integrates physiologically based pharmacokinetic (PBPK) modeling, Bayesian inference, and Markov chain Monte Carlo simulation to obtain a population estimate of environmental chloroform source concentrations consistent with human biomonitoring data. The biomonitoring data consist of chloroform blood concentrations measured as part of the Third National Health and Nutrition Examination Survey (NHANES III), and for which no corresponding exposure data were collected. Methods We used a combined PBPK and shower exposure model to consider several routes and sources of exposure: ingestion of tap water, inhalation of ambient household air, and inhalation and dermal absorption while showering. We determined posterior distributions for chloroform concentration in tap water and ambient household air using U.S. Environmental Protection Agency Total Exposure Assessment Methodology (TEAM) data as prior distributions for the Bayesian analysis. Results Posterior distributions for exposure indicate that 95% of the population represented by the NHANES III data had likely chloroform exposures ≤ 67 μg/L in tap water and ≤ 0.02 μg/L in ambient household air. Conclusions Our results demonstrate the application of computer simulation to aid in the interpretation of human biomonitoring data in the context of the exposure–health evaluation–risk assessment continuum. These results should be considered as a demonstration of the method and can be improved with the addition of more detailed data. PMID:18709138

Reduced growth of soybean seedlings after exposure to weak microwave radiation from GSM 900 mobile phone and base station.

PubMed

Halgamuge, Malka N; Yak, See Kye; Eberhardt, Jacob L

2015-02-01

The aim of this work was to study possible effects of environmental radiation pollution on plants. The association between cellular telephone (short duration, higher amplitude) and base station (long duration, very low amplitude) radiation exposure and the growth rate of soybean (Glycine max) seedlings was investigated. Soybean seedlings, pre-grown for 4 days, were exposed in a gigahertz transverse electromagnetic cell for 2 h to global system for mobile communication (GSM) mobile phone pulsed radiation or continuous wave (CW) radiation at 900 MHz with amplitudes of 5.7 and 41 V m(-1) , and outgrowth was studied one week after exposure. The exposure to higher amplitude (41 V m(-1)) GSM radiation resulted in diminished outgrowth of the epicotyl. The exposure to lower amplitude (5.7 V m(-1)) GSM radiation did not influence outgrowth of epicotyl, hypocotyls, or roots. The exposure to higher amplitude CW radiation resulted in reduced outgrowth of the roots whereas lower CW exposure resulted in a reduced outgrowth of the hypocotyl. Soybean seedlings were also exposed for 5 days to an extremely low level of radiation (GSM 900 MHz, 0.56 V m(-1)) and outgrowth was studied 2 days later. Growth of epicotyl and hypocotyl was found to be reduced, whereas the outgrowth of roots was stimulated. Our findings indicate that the observed effects were significantly dependent on field strength as well as amplitude modulation of the applied field. © 2015 Wiley Periodicals, Inc.

Biomarker analysis of liver cells exposed to surfactant-wrapped and oxidized multi-walled carbon nanotubes (MWCNTs).

PubMed

Henderson, W Matthew; Bouchard, Dermont; Chang, Xiaojun; Al-Abed, Souhail R; Teng, Quincy

2016-09-15

Carbon nanotubes (CNTs) have great potential in industrial, consumer, and mechanical applications, based partly on their unique structural, optical and electronic properties. CNTs are commonly oxidized or treated with surfactants to facilitate aqueous solution processing, and these CNT surface modifications also increase possible human and ecological exposures to nanoparticle-contaminated waters. To determine the exposure outcomes of oxidized and surfactant-wrapped multiwalled carbon nanotubes (MWCNTs) on biochemical processes, metabolomics-based profiling of human liver cells (C3A) was utilized. Cells were exposed to 0, 10, or 100ng/mL of MWCNTs for 24 and 48h; MWCNT particle size distribution, charge, and aggregation were monitored concurrently during exposures. Following MWCNT exposure, cellular metabolites were extracted, lyophilized, and buffered for (1)H NMR analysis. Acquired spectra were subjected to both multivariate and univariate analysis to determine the consequences of nanotube exposure on the metabolite profile of C3A cells. Resulting scores plots illustrated temporal and dose-dependent metabolite responses to all MWCNTs tested. Loadings plots coupled with t-test filtered spectra identified metabolites of interest. XPS analysis revealed the presence of hydroxyl and carboxyl functionalities on both MWCNTs surfaces. Metal content analysis by ICP-AES indicated that the total mass concentration of the potentially toxic impurities in the exposure experiments were extremely low (i.e. [Ni]≤2×10(-10)g/mL). Preliminary data suggested that MWCNT exposure causes perturbations in biochemical processes involved in cellular oxidation as well as fluxes in amino acid metabolism and fatty acid synthesis. Dose-response trajectories were apparent and spectral peaks related to both dose and MWCNT dispersion methodologies were determined. Correlations of the significant changes in metabolites will help to identify potential biomarkers associated with carbonaceous nanoparticle exposure. Published by Elsevier B.V.

Biologically based modeling of multimedia, multipathway, multiroute population exposures to arsenic

PubMed Central

Georgopoulos, Panos G.; Wang, Sheng-Wei; Yang, Yu-Ching; Xue, Jianping; Zartarian, Valerie G.; Mccurdy, Thomas; Özkaynak, Halûk

2011-01-01

This article presents an integrated, biologically based, source-to-dose assessment framework for modeling multimedia/multipathway/multiroute exposures to arsenic. Case studies demonstrating this framework are presented for three US counties (Hunderton County, NJ; Pima County, AZ; and Franklin County, OH), representing substantially different conditions of exposure. The approach taken utilizes the Modeling ENvironment for TOtal Risk studies (MENTOR) in an implementation that incorporates and extends the approach pioneered by Stochastic Human Exposure and Dose Simulation (SHEDS), in conjunction with a number of available databases, including NATA, NHEXAS, CSFII, and CHAD, and extends modeling techniques that have been developed in recent years. Model results indicate that, in most cases, the food intake pathway is the dominant contributor to total exposure and dose to arsenic. Model predictions are evaluated qualitatively by comparing distributions of predicted total arsenic amounts in urine with those derived using biomarker measurements from the NHEXAS — Region V study: the population distributions of urinary total arsenic levels calculated through MENTOR and from the NHEXAS measurements are in general qualitative agreement. Observed differences are due to various factors, such as interindividual variation in arsenic metabolism in humans, that are not fully accounted for in the current model implementation but can be incorporated in the future, in the open framework of MENTOR. The present study demonstrates that integrated source-to-dose modeling for arsenic can not only provide estimates of the relative contributions of multipathway exposure routes to the total exposure estimates, but can also estimate internal target tissue doses for speciated organic and inorganic arsenic, which can eventually be used to improve evaluation of health risks associated with exposures to arsenic from multiple sources, routes, and pathways. PMID:18073786

Ozone exposure- and flux-based response relationships with photosynthesis of winter wheat under fully open air condition.

PubMed

Feng, Zhaozhong; Calatayud, Vicent; Zhu, Jianguo; Kobayashi, Kazuhiko

2018-04-01

Five winter wheat cultivars were exposed to ambient (A-O 3 ) and elevated (E-O 3 , 1.5 ambient) O 3 in a fully open-air fumigation system in China. Ozone exposure- and flux based response relationships were established for seven physiological variables related to photosynthesis. The performance of the fitting of the regressions in terms of R 2 increased when second order regressions instead of first order ones were used, suggesting that effects of O 3 were more pronounced towards the last developmental stages of the wheat. The more robust indicators were those related with CO 2 assimilation, Rubisco activity and RuBP regeneration capacity (A sat , J max and Vc max ), and chlorophyll content (Chl). Flux-based metrics (POD y , Phytotoxic O 3 Dose over a threshold ynmolO 3 m -2 s -1 ) predicted slightly better the responses to O 3 than exposure metrics (AOTX, Accumulated O 3 exposure over an hourly Threshold of X ppb) for most of the variables. The best performance was observed for metrics POD 1 ( A sat , J max and Vc max ) and POD 3 (Chl). For this crop, the proposed response functions could be used for O 3 risk assessment based on physiological effects and also to include the influence of O 3 on yield or other variables in models with a photosynthetic component. Copyright © 2017 Elsevier B.V. All rights reserved.

An evaluation of indices that describe the impact of ozone on the yield of spring wheat ( Triticum aestivum L.)

NASA Astrophysics Data System (ADS)

Finnan, J. M.; Burke, J. I.; Jones, M. B.

A comparison of the performance of different ozone indices in exposure-response functions was made using crop yield and ozone monitoring data from spring wheat studies carried out within the framework of the European open-top chamber programme. Indices were calculated for a twelve-hour period (0900-2100 h, local time). An attempt was made to incorporate a measure of absorbed dose into current indices by weighting with simultaneous sunshine hour values. Both linear and Weibull models were fitted to the exposure-response data in order to evaluate index performance. Cumulative indices which employed continuous weighting functions (allometric or sigmoid) or which censored concentrations above threshold values performed best as they attributed increasing weight to higher concentrations. Indices which simply summed concentrations greater than or equal to a threshold value did not perform as well as equal weight was given to all concentrations greater than the threshold value. Model selection was found to be very important in determining the indices that best describe the relationship between exposure and response. In general weighting hourly ozone concentrations with the corresponding sunshine hour values in an attempt to incorporate this proposed measure of plant activity into current indices did not improve index performance. Ozone exposure indices accounted for a large proportion of the variability in data (91%) and it is suggested that a strong link exists between exposure and dose.

Indicators of alcohol consumption and attributable harm for monitoring and surveillance in European Union countries.

PubMed

Rehm, Jürgen; Scafato, Emanuele

2011-03-01

Alcohol is a major risk factor for burden of disease and injury in Europe, and contributes markedly to between region differences in life expectancy. Monitoring and surveillance systems have shown to be a key factor in implementing effective policies. The aim of this paper is to propose a system of indicators for alcohol consumption and attributable harm which can be used as an over-time monitoring tool at the country level as well as for comparisons between countries. A systematic research in electronic data bases was conducted but most of the information was derived from ongoing international efforts to establish alcohol monitoring and surveillance systems. European Union. Countries. Exposure to alcohol, mortality, burden of disease. Adult per capita alcohol consumption, prevalence of abstention, and frequency of drinking more than 60 g pure alcohol in one occasion are proposed as a minimal set of alcohol exposure indicators, which can quickly be implemented in all EU countries. With respect to health harm indicators, the best minimal choice which can be implemented quickly in all countries of the EU would be alcohol-attributable years of life lost due to premature death. In addition, country specific indicators could be added, when alcohol places specific burden on specific diseases. National and European Union-wide monitoring systems for alcohol exposure and attributable harm to inform public health-related policy decisions could be implemented easily. The establishement of such monitoring systems would follow the recent World Assembly resolution for a global strategy to reduce alcohol-related harm. © 2011 The Authors, Addiction © 2011 Society for the Study of Addiction.

A field-based approach for assessing the impact of paper pulp mill effluent on the metbolite profile of fathead minnows (Pimephales promelas)

EPA Science Inventory

Although evidence indicates that exposure to effluent from paper pulp mills (PME) can alter the body condition, secondary sexual characteristics, and reproductive success of aquatic organisms, there is currently little understanding of the biochemical mechanisms for these effects...

Environmental Pollution: Is There Enough Public Concern to Lead to Action?

ERIC Educational Resources Information Center

Sharma, Navin C.; And Others

1975-01-01

Research indicates that the impetus to solve pollution problems may have to come from processes outside the realm of ordinary problem solving institutions. Mass media exposure and involvement in the political process are ineffective in generating antipollution sentiment. "Grass roots" movements based on informal communication may emerge to combat…

Longitudinal Associations of Exposure to Perfluoroalkylated Substances in Childhood and Adolescence and Indicators of Adiposity and Glucose Metabolism 6 and 12 Years Later: The European Youth Heart Study.

PubMed

Domazet, Sidsel L; Grøntved, Anders; Timmermann, Amalie G; Nielsen, Flemming; Jensen, Tina K

2016-10-01

To investigate the long-term association of exposure to perfluoroalkylated substances, including perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA), during childhood (9 years) and adolescence (15 years) on indicators of adiposity and glucose metabolism in adolescence (15 years) and young adulthood (21 years). Secondarily, we aim to clarify the degree of tracking of exposure from childhood into young adulthood. Data derived from a large multicenter prospective cohort study, in which the same participants have been observed from childhood (N = 590), during adolescence (N = 444), and into young adulthood (N = 369). Stored plasma samples were analyzed for PFOS and PFOA. Indicators of adiposity comprising body height, body weight, sum of four skinfolds, and waist circumference, as well as indicators of glucose metabolism, comprising fasting blood glucose, triglyceride, and insulin levels, β-cell function, and insulin resistance, have been collected at all study waves. Multiple linear regression was applied in order to model earlier exposure on later outcome while controlling for baseline outcome levels, sex, age, and socioeconomic factors. Childhood exposure to PFOS was associated with indicators of adiposity at 15 years of age that are displayed in elevated BMI, skinfold thickness, and waist circumference, as well as increased skinfold thickness and waist circumference at 21 years of age. PFOA exposure in childhood was associated with decreased β-cell function at 15 years of age. We did not observe associations between exposure during adolescence and indicators of adiposity and glucose metabolism in young adulthood. This study found evidence for childhood exposure to PFOS and PFOA predicting adiposity at 15 and 21 years of age and impaired β-cell function at 15 years of age, respectively. © 2016 by the American Diabetes Association.

Influence of walking route choice on primary school children's exposure to air pollution--A proof of concept study using simulation.

PubMed

Mölter, Anna; Lindley, Sarah

2015-10-15

This study developed a walking network for the Greater Manchester area (UK). The walking network allows routes to be calculated either based on the shortest duration or based on the lowest cumulative nitrogen dioxide (NO2) or particulate matter (PM10) exposure. The aim of this study was to analyse the costs and benefits of faster routes versus lower pollution exposure for walking routes to primary schools. Random samples of primary schools and residential addresses were used to generate 100,000 hypothetical school routes. For 60% (59,992) and 40% (40,460) an alternative low NO2 and PM10 route was found, respectively. The median change in travel time (NO2: 4.5s, PM10: 0.5s) and average route exposure (NO2: -0.40 μg/m(3), PM10: -0.03 μg/m(3)) was small. However, quantile regression analysis indicated that for 50% of routes a 1% increase in travel time was associated with a 1.5% decrease in NO2 and PM10 exposure. The results of this study suggest that the relative decrease in pollution exposure on low pollution routes tends to be greater than the relative increase in route length. This supports the idea that a route planning tool identifying less polluted routes to primary schools could help deliver potential health benefits for children. Copyright © 2015 Elsevier B.V. All rights reserved.

Treatment of challenging behavior exhibited by children with prenatal drug exposure.

PubMed

Kurtz, Patricia F; Chin, Michelle D; Rush, Karena S; Dixon, Dennis R

2008-01-01

A large body of literature exists describing the harmful effects of prenatal drug exposure on infant and child development. However, there is a paucity of research examining strategies to ameliorate sequelae such as externalizing behavior problems. In the present study, functional analysis procedures were used to assess challenging behavior exhibited by two children who were prenatally exposed to drugs of abuse. Results for both children indicated that challenging behavior was maintained by access to positive reinforcement (adult attention and tangible items). For one child, challenging behavior was also maintained by negative reinforcement (escape from activities of daily living). Function-based interventions were effective in reducing challenging behavior for both children. Implications for utilizing methods of applied behavior analysis in research with children with prenatal drug exposure are discussed.

Low earth orbit durability evaluation of Haynes 188 solar receiver material

NASA Technical Reports Server (NTRS)

De Groh, Kim K.; Rutledge, Sharon K.; Burke, Christopher A.; Dever, Therese M.; Olle, Raymond M.; Terlep, Judith A.

1992-01-01

The effects of elevated-temperature vacuum and elevated-temperature atomic oxygen exposure on the mass, surface chemistry, surface morphology, and optical properties of Haynes 188, a possible heat receiver material for space-based solar dynamic power systems, have been studied. Pristine and surface modified Haynes 188 were exposed to vacuum less than or equal to 10 exp -6 torr at 820 C for 5215.5 h, and to atomic oxygen in an air plasma asher at 34 and 827 C for fluences up to 5.6 x 10 exp 21 atoms/sq cm. Results obtained indicate that vacuum heat treatment caused surface morphology and chemistry changes with corresponding optical property changes. Atomic oxygen exposure caused optical property changes which diminished with time. Mass changes are considered to be negligible for both exposures.

Impacts of Lateral Boundary Conditions on US Ozone ...

EPA Pesticide Factsheets

Chemical boundary conditions are a key input to regional-scale photochemical models. In this study, we perform annual simulations over North America with chemical boundary conditions prepared from two global models (GEOS-CHEM and Hemispheric CMAQ). Results indicate that the impacts of different boundary conditions on ozone can be significant throughout the year. The National Exposure Research Laboratory (NERL) Computational Exposure Division (CED) develops and evaluates data, decision-support tools, and models to be applied to media-specific or receptor-specific problem areas. CED uses modeling-based approaches to characterize exposures, evaluate fate and transport, and support environmental diagnostics/forensics with input from multiple data sources. It also develops media- and receptor-specific models, process models, and decision support tools for use both within and outside of EPA.

Patulin in domestic and imported apple-based drinks in Belgium: occurrence and exposure assessment.

PubMed

Tangni, E K; Theys, R; Mignolet, E; Maudoux, M; Michelet, J Y; Larondelle, Y

2003-05-01

Apple-based beverages are regularly consumed by adults and children in Belgium. They are locally produced or imported from other countries. The apples used as starting material for these productions are frequently contaminated by mycotoxin-producing moulds and damaged during transport and handling. The current study was undertaken to investigate whether patulin (PAT) is present in the industrial or handicraft-made apple juices and ciders consumed by the Belgian population and to assess the population's exposure to this mycotoxin through apple-based drinks. Belgian (n = 29) and imported (14) apple juices as well as ciders (7) were assayed for PAT by high-performance liquid chromatography with ultraviolet light detection. PAT was detected respectively in 79, 86 and 43% of these tested samples. However, no contaminated sample exceeded the safe level of 50 microg PAT l(-1). Levels of PAT contamination were comparable in Belgian and imported juice samples. The overall mean PAT concentrations were 9.0 and 3.4 microg l(-1) for contaminated apple juices and ciders, respectively. This study also indicates that there was no statistically significant difference in the mean PAT contamination between clear (7.8 microg l(-1)) and cloudy (10.7 microg l(-1)) apple juices, as well as between handicraft-made apple juices (14.6 microg l(-1)) and industrial ones (7.0 microg l(-1)). On the basis of the mean results, a consumer exposure assessment indicates that a daily intake of 0.2 litres apple juice contributes to 45% of the provisional maximum tolerable daily intake for a child of 10 kg body weight.

Modeled methylmercury exposure and risk from rice consumption for vulnerable populations in a traditional fish-eating area in China.

PubMed

Tong, Yin-Dong; Ou, Lang-Bo; Chen, Long; Wang, Huan-Huan; Chen, Cen; Wang, Xue-Jun; Zhang, Wei; Wang, Qi-Guang

2015-05-01

The circulation of rice from contaminated areas could escalate exposure risk from a local problem to a national issue and affect a wider population beyond the region of origin, as confirmed by the "Poison Rice Incident" in May 2013 in Guangzhou, China. In the present study, the authors established a food chain model based on the aquivalence method to identify major sources of methylmercury (MeHg), estimate the levels of MeHg, and quantify exposure to MeHg via rice and aquatic food consumption. Different types of organism samples from the Haihe River also were collected to verify the calculated values. The MeHg intake in pregnant women was 1529.1 ng/d from the aquatic food chain and as high as 2804.0 ng/d from rice, although the intake varied among scenarios. The maximum possible MeHg concentration in the blood of pregnant women was 5.21 µg/L, higher than the threshold value of MeHg recommended by the US Environmental Protection Agency (4.4 µg/L), which indicated that pregnant women could face risk from MeHg exposure. The authors also assessed the risk of MeHg exposure in pregnant women and their breastfed infants using a new index, HQEquivalent . In 4 scenarios, the HQEquivalent indices ranged from 0.42 to 1.18 for pregnant women and from 0.29 to 0.83 for breastfed infants. © 2014 SETAC.

Predictive Indicators of Overuse Injuries in Adolescent Endurance Athletes.

PubMed

Martínez-Silván, Daniel; Díaz-Ocejo, Jaime; Murray, Andrew

2017-04-01

To analyze the influence of training exposure and the utility of self-report questionnaires on predicting overuse injuries in adolescent endurance athletes. Five adolescent male endurance athletes (15.7 ± 1.4 y) from a full-time sports academy answered 2 questionnaires (Recovery Cue; RC-q and Oslo Sports Trauma Research questionnaire; OSTRC-q) on a weekly basis for 1 season (37 wk) to detect signs of overtraining and underrecovery (RC-q) and early symptoms of lower-limb injuries (OSTRC-q). All overuse injuries were retrospectively analyzed to detect which variations in the questionnaires in the weeks preceding injury were best associated. Overuse incidence rates were calculated based on training exposure. Lower-limb overuse injuries accounted for 73% of total injuries. The incidence rate for overuse training-related injuries was 10 injuries/1000 h. Strong correlations were observed between individual running exposure and overuse injury incidence (r 2 = .66), number of overuse injuries (r 2 = .69), and days lost (r 2 = .66). A change of 20% or more in the RC-q score in the preceding week was associated with 67% of the lower-limb overuse injuries. Musculoskeletal symptoms were only detected in advance by the OSTRC-q in 27% of the episodes. Training exposure (especially running exposure) was shown to be related to overuse injuries, suggesting that monitoring training load is a key factor for injury prevention. Worsening scores in the RC-q (but not the OSTRC) may be an indicator of overuse injury in adolescent endurance runners when used longitudinally.

Toxic effects of juvenile sablefish, Anoplopoma fimbria by ammonia exposure at different water temperature.

PubMed

Kim, Jun-Hwan; Park, Hee-Ju; Hwang, In-Ki; Han, Jae-Min; Kim, Do-Hyung; Oh, Chul Woong; Lee, Jung-Sick; Kang, Ju-Chan

2017-09-01

Juvenile sablefish, Anoplopoma fimbria (mean length 17.1±2.4cm, and mean weight 75.6±5.7g) were used to evaluate toxic effects on antioxidant systems, immune responses, and stress indicators by ammonia exposure (0, 0.25, 0.75, and 1.25mg/L) at different water temperature (12 and 17°C) in 1 and 2 months. In antioxidant responses, superoxide dismutase (SOD) and catalase (CAT) were significantly increased by ammonia exposure, whereas glutathione (GSH) was decreased. In immune responses, lysozyme and phagocytosis activity were significantly increased by ammonia exposure. In stress indicators, plasma glucose, heat shock protein 70 (HSP 70), and cortisol were significantly increased. At high water temperature (17°C), alterations by ammonia exposure were more distinctly. The results of this study indicated that ammonia exposure can induce toxic effects in the sablefish, and high water temperature can affect the ammonia exposure toxicity. Copyright © 2017 Elsevier B.V. All rights reserved.

Framework for mapping the drivers of coastal vulnerability and spatial decision making for climate-change adaptation: A case study from Maharashtra, India.

PubMed

Krishnan, Pandian; Ananthan, Pachampalayam Shanmugam; Purvaja, Ramachandran; Joyson Joe Jeevamani, Jeyapaul; Amali Infantina, John; Srinivasa Rao, Cherukumalli; Anand, Arur; Mahendra, Ranganalli Somashekharappa; Sekar, Iyyapa; Kareemulla, Kalakada; Biswas, Amit; Kalpana Sastry, Regulagedda; Ramesh, Ramachandran

2018-05-31

The impacts of climate change are of particular concern to the coastal region of tropical countries like India, which are exposed to cyclones, floods, tsunami, seawater intrusion, etc. Climate-change adaptation presupposes comprehensive assessment of vulnerability status. Studies so far relied either on remote sensing-based spatial mapping of physical vulnerability or on certain socio-economic aspects with limited scope for upscaling or replication. The current study is an attempt to develop a holistic and robust framework to assess the vulnerability of coastal India at different levels. We propose and estimate cumulative vulnerability index (CVI) as a function of exposure, sensitivity and adaptive capacity, at the village level, using nationally comparable and credible datasets. The exposure index (EI) was determined at the village level by decomposing the spatial multi-hazard maps, while sensitivity (SI) and adaptive capacity indices (ACI) were estimated using 23 indicators, covering social and economic aspects. The indicators were identified through the literature review, expert consultations, opinion survey, and were further validated through statistical tests. The socio-economic vulnerability index (SEVI) was constructed as a function of sensitivity and adaptive capacity for planning grassroot-level interventions and adaptation strategies. The framework was piloted in Sindhudurg, a coastal district in Maharashtra, India. It comprises 317 villages, spread across three taluks viz., Devgad, Malvan and Vengurla. The villages in Sindhudurg were ranked based on this multi-criteria approach. Based on CVI values, 92 villages (30%) in Sindhudurg were identified as highly vulnerable. We propose a decision tool for identifying villages vulnerable to changing climate, based on their level of sensitivity and adaptive capacity in a two-dimensional matrix, thus aiding in planning location-specific interventions. Here, vulnerability indicators are classified and designated as 'drivers' (indicators with significantly high values and intervention priority) and 'buffers' (indicators with low-to-moderate values) at the village level. The framework provides for aggregation or decomposition of CVI and other sub-indices, in order to plan spatial contingency plans and enable swift action for climate adaptation.

Biomonitoring of Environmental Status and Trends (BEST) Program: selected methods for monitoring chemical contaminants and their effects in aquatic ecosystems

USGS Publications Warehouse

Schmitt, Christopher J.; Dethloff, Gail M.

2000-01-01

This document describes the suite of biological methods of the U.S. Geological Survey- Biomonitoring of Environmental Status and Trends program for monitoring chemical contaminants and their effects on fish. The methods, which were selected by panels of experts, are being field-tested in rivers of the Mississippi River, Columbia River, and Rio Grande basins. General health biomarkers include a health assessment index based on gross observation; histopathological examination of selected organs and tissues; condition factor; and the heptosomatic and splenosomatic indices. Immune system indicators are plasma lysozyme activity and measures of splenic macrophage aggregates. Reproductive biomarkers include plasma concentrations of sex steroid hormones (17b-estradiol and 11-ketotestosterone) and vitellogenin, gonadal histopathology (including reproductive stage and, in females, gonadal atresia), and the gonadosomatic index. Indicators of exposure to polycyclic aromatic and polyhalogenated hydrocarbons are the H4IIE rat hepatoma cell bioassay (performed on solvent extracts of composite fish samples) and hepatic ethoxyresorufin-O-deethylase activity. Stable nitrogen isotope ratios are used to assess the trophic position of the fish and their exposure to sewage and other animal wastes. For each indicator we describe endpoint(s) and methods, and discuss the indicator?s value and limitations for contaminant monitoring and assessment.

Lung cancer incidence among Norwegian silicon carbide industry workers: associations with particulate exposure factors

PubMed Central

Kjærheim, Kristina; Føreland, Solveig; Eduard, Wijnand; Kjuus, Helge

2012-01-01

Objectives An increased lung cancer risk associated with total dust exposure in the silicon carbide (SiC) industry has previously been reported. The aim of the present study was to examine the relative importance of specific exposure factors by using a comprehensive, historic job exposure matrix based on about 8000 measurements. Methods Cumulative exposure to total and respirable dust, respirable quartz, cristobalite, and SiC particles and SiC fibres was assessed for 1687 long-term workers employed during 1913–2003 in the Norwegian SiC industry. Standardised incidence ratios for lung cancer, with follow-up during 1953–2008, were calculated stratified by cumulative exposure categories. Poisson regression analyses were performed using both categorised and log-transformed cumulative exposure variables. Results The lung cancer incidence was about twofold increased at the highest level of exposure to each of the exposure factors (standardised incidence ratios 1.9–2.3 for all agents). Internal analyses showed associations between exposure level and lung cancer incidence for all investigated factors, but a significant trend only for total dust and cristobalite. In multivariate analyses, cristobalite showed the most consistent associations, followed by SiC fibres. Conclusions The results indicated that crystalline silica in the form of cristobalite was the most important occupational exposure factor responsible for lung cancer excess in the Norwegian SiC industry. SiC fibres seemed to have an additional effect. PMID:22611173

Aggregated data from two double-blind base station provocation studies comparing individuals with idiopathic environmental intolerance with attribution to electromagnetic fields and controls.

PubMed

Eltiti, Stacy; Wallace, Denise; Russo, Riccardo; Fox, Elaine

2015-02-01

Data from two previous studies were aggregated to provide a statistically powerful test of whether exposure to electromagnetic fields (EMFs) produced by telecommunication base stations negatively affects well-being in individuals who report idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) and control participants. A total of 102 IEI-EMF and 237 controls participated in open provocation trials and 88 IEI-EMF and 231 controls went on to complete double-blind trials in which they were exposed to EMFs from a base station emitting either a Global System for Mobile Communication and Universal Mobile Telecommunications System or a Terrestrial Trunked Radio Telecommunications System signal. Both experiments included a comparison sham condition. Visual analog and symptom scales measured subjective well-being. Results showed that IEI-EMF participants reported lower levels of well-being during real compared to sham exposure during open provocation, but not during double-blind trials. Additionally, participants reported lower levels of well-being during high compared to low load trials and this did not interact with radiofrequency-EMF exposure. These findings are consistent with a growing body of literature indicating there is no causal relationship between short-term exposure to EMFs and subjective well-being in members of the public whether or not they report perceived sensitivity to EMFs. © 2015 Wiley Periodicals, Inc.

Factors associated with secondhand smoke exposure in different settings: Results from the German Health Update (GEDA) 2012.

PubMed

Fischer, Florian; Kraemer, Alexander

2016-04-14

The ubiquity of secondhand smoke (SHS) exposure at home or in private establishments, workplaces and public areas poses several challenges for the reduction of SHS exposure. This study aimed to describe the prevalence of SHS exposure in Germany and key factors associated with exposure. Results were also differentiated by place of exposure. A secondary data analysis based on the public use file of the German Health Update 2012 was conducted (n = 13,933). Only non-smokers were included in the analysis. In a multivariable logistic regression model the factors associated with SHS exposure were calculated. In addition, a further set of multivariable logistic regressions were calculated for factors associated with the place of SHS exposure (workplace, at home, bars/discotheques, restaurants, at the house of a friend). More than a quarter of non-smoking study participants were exposed to SHS. The main area of exposure was the workplace (40.9 %). The multivariable logistic regression indicated young age as the most important factor associated with SHS exposure. The odds for SHS exposure was higher in men than in women. The likelihood of SHS exposure decreased with higher education. SHS exposure and the associated factors varied between different places of exposure. Despite several actions to protect non-smokers which were implemented in Germany during the past years, SHS exposure still remains a relevant risk factor at a population level. According to the results of this study, particularly the workplace and other public places such as bars and discotheques have to be taken into account for the development of strategies to reduce SHS exposure.

Hydrogen Purification Using Natural Zeolite Membranes

NASA Technical Reports Server (NTRS)

DelValle, William

2003-01-01

The School of Science at Universidad del Turabo (UT) have a long-lasting investigation plan to study the hydrogen cleaning and purification technologies. We proposed a research project for the synthesis, phase analysis and porosity characterization of zeolite based ceramic perm-selective membranes for hydrogen cleaning to support NASA's commitment to achieving a broad-based research capability focusing on aerospace-related issues. The present study will focus on technology transfer by utilizing inorganic membranes for production of ultra-clean hydrogen for application in combustion. We tested three different natural zeolite membranes (different particle size at different temperatures and time of exposure). Our results show that the membranes exposured at 900 C for 1Hr has the most higher permeation capacity, indicated that our zeolite membranes has the capacity to permeate hydrogen.

Urban gardens: Lead exposure, recontamination mechanisms, and implications for remediation design

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clark, Heather F.; Hausladen, Debra M.; Brabander, Daniel J.

2008-07-15

Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 {mu}g/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed thatmore » the lead concentration increased from an initial range of 150{+-}40 {mu}g/g to an average of 336 {mu}g/g over 4 years. The percent distribution of lead in the fine grain soil (<100 {mu}m) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (<100 {mu}m) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale.« less

Urban gardens: lead exposure, recontamination mechanisms, and implications for remediation design.

PubMed

Clark, Heather F; Hausladen, Debra M; Brabander, Daniel J

2008-07-01

Environmental lead contamination is prevalent in urban areas where soil represents a significant sink and pathway of exposure. This study characterizes the speciation of lead that is relevant to local recontamination and to human exposure in the backyard gardens of Roxbury and Dorchester, MA, USA. One hundred forty-one backyard gardens were tested by X-ray fluorescence, and 81% of gardens have lead levels above the US EPA action limit of 400 microg/g. Raised gardening beds are the in situ exposure reduction method used in the communities to promote urban gardening. Raised beds were tested for lead and the results showed that the lead concentration increased from an initial range of 150+/-40 microg/g to an average of 336 microg/g over 4 years. The percent distribution of lead in the fine grain soil (<100 microm) and the trace metal signature of the raised beds support the conclusion that the mechanism of recontamination is wind-transported particles. Scanning electron microscopy and sequential extraction were used to characterize the speciation of lead, and the trace metal signature of the fine grain soil in both gardens and raised gardening beds is characteristic of lead-based paint. This study demonstrates that raised beds are a limited exposure reduction method and require maintenance to achieve exposure reduction goals. An exposure model was developed based on a suite of parameters that combine relevant values from the literature with site-specific quantification of exposure pathways. This model suggests that consumption of homegrown produce accounts for only 3% of children's daily exposure of lead while ingestion of fine grained soil (<100 microm) accounts for 82% of the daily exposure. This study indicates that urban lead remediation on a yard-by-yard scale requires constant maintenance and that remediation may need to occur on a neighborhood-wide scale.

An ecological risk assessment of the acute and chronic effects of the herbicide clopyralid to rainbow trout (Oncorhynchus mykiss)

USGS Publications Warehouse

Fairchild, J.F.; Allert, A.L.; Feltz, K.P.; Nelson, K.J.; Valle, J.A.

2009-01-01

Clopyralid (3,6-dichloro-2-pyridinecarboxylic acid) is a pyridine herbicide frequently used to control invasive, noxious weeds in the northwestern United States. Clopyralid exhibits low acute toxicity to fish, including the rainbow trout (Oncorhynchus mykiss) and the threatened bull trout (Salvelinus confluentus). However, there are no published chronic toxicity data for clopyralid and fish that can be used in ecological risk assessments. We conducted 30-day chronic toxicity studies with juvenile rainbow trout exposed to the acid form of clopyralid. The 30-day maximum acceptable toxicant concentration (MATC) for growth, calculated as the geometric mean of the no observable effect concentration (68 mg/L) and the lowest observable effect concentration (136 mg/L), was 96 mg/L. No mortality was measured at the highest chronic concentration tested (273 mg/L). The acute:chronic ratio, calculated by dividing the previously published 96-h acutely lethal concentration (96-h ALC50; 700 mg/L) by the MATC was 7.3. Toxicity values were compared to a four-tiered exposure assessment profile assuming an application rate of 1.12 kg/ha. The Tier 1 exposure estimation, based on direct overspray of a 2-m deep pond, was 0.055 mg/L. The Tier 2 maximum exposure estimate, based on the Generic Exposure Estimate Concentration model (GEENEC), was 0.057 mg/L. The Tier 3 maximum exposure estimate, based on previously published results of the Groundwater Loading Effects of Agricultural Management Systems model (GLEAMS), was 0.073 mg/L. The Tier 4 exposure estimate, based on published edge-of-field monitoring data, was estimated at 0.008 mg/L. Comparison of toxicity data to estimated environmental concentrations of clopyralid indicates that the safety factor for rainbow trout exposed to clopyralid at labeled use rates exceeds 1000. Therefore, the herbicide presents little to no risk to rainbow trout or other salmonids such as the threatened bull trout. ?? 2009 US Government.

Quantitative assessment of airborne exposures generated during common cleaning tasks: a pilot study

PubMed Central

2010-01-01

Background A growing body of epidemiologic evidence suggests an association between exposure to cleaning products with asthma and other respiratory disorders. Thus far, these studies have conducted only limited quantitative exposure assessments. Exposures from cleaning products are difficult to measure because they are complex mixtures of chemicals with a range of physicochemical properties, thus requiring multiple measurement techniques. We conducted a pilot exposure assessment study to identify methods for assessing short term, task-based airborne exposures and to quantitatively evaluate airborne exposures associated with cleaning tasks simulated under controlled work environment conditions. Methods Sink, mirror, and toilet bowl cleaning tasks were simulated in a large ventilated bathroom and a small unventilated bathroom using a general purpose, a glass, and a bathroom cleaner. All tasks were performed for 10 minutes. Airborne total volatile organic compounds (TVOC) generated during the tasks were measured using a direct reading instrument (DRI) with a photo ionization detector. Volatile organic ingredients of the cleaning mixtures were assessed utilizing an integrated sampling and analytic method, EPA TO-17. Ammonia air concentrations were also measured with an electrochemical sensor embedded in the DRI. Results Average TVOC concentrations calculated for 10 minute tasks ranged 0.02 - 6.49 ppm and the highest peak concentrations observed ranged 0.14-11 ppm. TVOC time concentration profiles indicated that exposures above background level remained present for about 20 minutes after cessation of the tasks. Among several targeted VOC compounds from cleaning mixtures, only 2-BE was detectable with the EPA method. The ten minute average 2- BE concentrations ranged 0.30 -21 ppm between tasks. The DRI underestimated 2-BE exposures compared to the results from the integrated method. The highest concentration of ammonia of 2.8 ppm occurred during mirror cleaning. Conclusions Our results indicate that airborne exposures from short-term cleaning tasks can remain in the air even after tasks' cessation, suggesting potential exposures to anyone entering the room shortly after cleaning. Additionally, 2-BE concentrations from cleaning could approach occupational exposure limits and warrant further investigation. Measurement methods applied in this study can be useful for workplace assessment of airborne exposures during cleaning, if the limitations identified here are addressed. PMID:21118559

Vulnerability assessment including tangible and intangible components in the index composition: An Amazon case study of flooding and flash flooding.

PubMed

Andrade, Milena Marília Nogueira de; Szlafsztein, Claudio Fabian

2018-07-15

The vulnerability of cities and communities in the Amazon to flooding and flash flooding is increasing. The effects of extreme events on populations vary across landscapes, causing vulnerability to differ spatially. Traditional vulnerability studies in Brazil and across the world have used the vulnerability index for the country and, more recently, municipality scales. The vulnerability dimensions are exposure, sensitivity, and adaptive capacity. For each of these dimensions, there is a group of indicators that constitutes a vulnerability index using quantitative data. Several vulnerability assessments have used sensitivity and exposure analyses and, recently, adaptive capacity has been considered. The Geographical Information Systems (GIS) analysis allows spatial regional modeling using quantitative vulnerability indicators. This paper presents a local-scale vulnerability assessment in an urban Amazonian area, Santarém City, using interdisciplinary methods. Data for exposure and sensitivity were gathered by remote sensing and census data, respectively. However, adaptive capacity refers to local capacities, whether infrastructural or not, and the latter were gathered by qualitative participatory methods. For the mixed data used to study adaptive capacity, we consider tangible components for countable infrastructure that can cope with hazards, and intangible components that reflect social activities based on risk perceptions and collective action. The results indicate that over 80% of the area is highly or moderately vulnerable to flooding and flash flooding. Exposure and adaptive capacity were determinants of the results. Lower values of adaptive capacity play a significant role in vulnerability enhancement. Copyright © 2018 Elsevier B.V. All rights reserved.

Residential Proximity to Heavy-Traffic Roads, Benzene Exposure, and Childhood Leukemia-The GEOCAP Study, 2002-2007.

PubMed

Houot, Jennifer; Marquant, Fabienne; Goujon, Stéphanie; Faure, Laure; Honoré, Cécile; Roth, Marie-Hélène; Hémon, Denis; Clavel, Jacqueline

2015-10-15

Childhood leukemia may be associated with traffic-related environmental exposure to benzene, and additional data are needed. The Géolocalisation des Cancers Pédiatriques (GEOCAP) Study, a nationwide French case-control study, was designed to avoid selection bias due to differential participation and misclassification. The study compared the 2,760 childhood leukemia cases diagnosed in France between 2002 and 2007 (including 2,275 cases of acute lymphoblastic leukemia (ALL) and 418 cases of acute myeloblastic leukemia (AML)) with 30,000 contemporaneous child population controls. The residence addresses were precisely geocoded, and 3 indicators of residential proximity to traffic were considered. Estimates of benzene concentrations were also available for the Île-de-France region (including Paris). A 300-m increase in major road length within 150 m of the geocoded address was significantly associated with AML (odds ratio = 1.2, 95% confidence interval: 1.0, 1.4) but not with ALL (odds ratio = 1.0, 95% confidence interval: 0.9, 1.1), and the association was reinforced in the Île-de-France region when this indicator was combined with benzene estimates. These results, which were free from any participation bias and based on objectively determined indices of exposure, showed an increased incidence of AML associated with heavy-traffic road density near a child's home. The results support a role for traffic-related benzene exposure in the etiology of childhood AML. © The Author 2015. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Change of exposure response over time and long-term risk of silicosis among a cohort of Chinese pottery workers.

PubMed

Sun, Yi; Bochmann, Frank; Morfeld, Peter; Ulm, Kurt; Liu, Yuewei; Wang, Heijiao; Yang, Lei; Chen, Weihong

2011-07-01

An analysis was conducted on a cohort of Chinese pottery workers to estimate the exposure-response relationship between respirable crystalline silica dust exposure and the incidence of radiographically diagnosed silicosis, and to estimate the long-term risk of developing silicosis until the age of 65. The cohort comprised 3,250 employees with a median follow-up duration of around 37 years. Incident cases of silicosis were identified via silicosis registries (Chinese X-ray stage I, similar to International Labor Organisation classification scheme profusion category 1/1). Individual exposure to respirable crystalline silica dust was estimated based on over 100,000 historical dust measurements. The association between dust exposure, incidence and long-time risk of silicosis was quantified by Poisson regression analysis adjusted for age and smoking. The risk of silicosis depended not only on the cumulative respirable crystalline silica dust exposures, but also on the time-dependent respirable crystalline silica dust exposure pattern (long-term average concentration, highest annual concentration ever experienced and time since first exposure). A long-term "excess" risk of silicosis of approximately 1.5/1,000 was estimated among workers with all annual respirable crystalline silica dust concentration estimates less than 0.1 mg/m(3), using the German measurement strategy. This study indicates the importance of proper consideration of exposure information in risk quantification in epidemiological studies.

Neurocognitive and neurodevelopmental impact of prenatal methamphetamine exposure: A comparison study of prenatally exposed children with nonexposed ADHD peers.

PubMed

Brinker, Michael J; Cohen, Jodie G; Sharrette, Johnathan A; Hall, Trevor A

2017-11-29

Prenatal methamphetamine exposure has become an increasingly pervasive concern, especially in rural-based populations and populations of lower socioeconomic status. While research has begun to highlight the effects of prenatal methamphetamine exposure, the long-term impact of this exposure remains an under-investigated topic. This study attempts to investigate the neurocognitive and neurodevelopmental effects of prenatal methamphetamine exposure by comparing the index and full-scale IQ scores on the WISC-IV between a sample of clinically referred children prenatally exposed to methamphetamine (N = 80) and a sample of clinically referred nonexposed children diagnosed with ADHD (N = 44). Children prenatally exposed to methamphetamine showed significantly lower scores on all WISC-IV domains when compared to peers with ADHD. When taking into account polysubstance exposure to alcohol, these differences remained statistically significant, with the exception of the Processing Speed Index (PSI); children reported to have been prenatally exposed to methamphetamine and to alcohol (PME) remained below ADHD peers on all other WISC-IV index scores. Within the prenatally exposed sample, regression analyses indicated that age was a significant negative predictor of PSI scores. Overall findings suggest that prenatal methamphetamine exposure is associated with a notable cognitive impact independent of polysubstance exposure to alcohol, and that the impact of this exposure on processing speed skills may become more pronounced with age.

Reducing attenuation in exposure-response relationships by exposure modeling and grouping: the relationship between wood dust exposure and lung function.

PubMed

Teschke, Kay; Spierings, Judith; Marion, Stephen A; Demers, Paul A; Davies, Hugh W; Kennedy, Susan M

2004-12-01

In a study of wood dust exposure and lung function, we tested the effect on the exposure-response relationship of six different exposure metrics using the mean measured exposure of each subject versus the mean exposure based on various methods of grouping subjects, including job-based groups and groups based on an empirical model of the determinants of exposure. Multiple linear regression was used to examine the association between wood dust concentration and forced expiratory volume in 1s (FEV(1)), adjusting for age, sex, height, race, pediatric asthma, and smoking. Stronger point estimates of the exposure-response relationships were observed when exposures were based on increasing levels of aggregation, allowing the relationships to be found statistically significant in four of the six metrics. The strongest point estimates were found when exposures were based on the determinants of exposure model. Determinants of exposure modeling offers the potential for improvement in risk estimation equivalent to or beyond that from job-based exposure grouping.

Clients' Perception of Outcome of Team-Based Prenatal and Reproductive Genetic Counseling in Serbian Service Using the Perceived Personal Control (PPC) Questionnaire.

PubMed

Cuturilo, Goran; Vucinic, Olivera Kontic; Novakovic, Ivana; Ignjatovic, Svetlana; Mijovic, Marija; Sulovic, Nenad; Vukolic, Dusan; Komnenic, Milica; Tadic, Jasmina; Cetkovic, Aleksandar; Belic, Aleksandra; Ljubic, Aleksandar

2016-02-01

This is the first study in Serbia and the region of South-East Europe dedicated to clients' perception of outcome and efficiency of prenatal and reproductive genetic counseling. The primary aim of this study was to assess overall value and success of genetic counseling in prenatal and reproductive care with regard to perceived personal control of clients, reflecting also in a part patient comprehension, knowledge retention, and empowerment in decision-making. The standardized Perceived Personal Control questionnaire (PPC) was used for the assessment of 239 female participants. First, we performed a complete validation of the psychometric characteristics of the Serbian-language version of the PPC questionnaire. The validation of the questionnaire permits other researchers from Serbian-speaking regions of South-East Europe to use this standard instrument to assess the effectiveness of prenatal genetic counseling in their communities and analyze advantages and disadvantages of their counseling models. We also measured social and demographic characteristics of participants. Further, we analyzed effects of our team-based prenatal and reproductive genetic counseling model through (a) calculation of PPC scores at three different stages (before initial, after initial, and before second counseling session), and (b) by assessing participants' responses by indication for referral (advanced maternal age, abnormal biochemical screening, family history of hereditary disorders, maternal exposure to drugs, exposure to radiation, exposure to infective agents, infertility or recurrent abortions, and miscellaneous). The results indicate that participants' knowledge after initial counseling increased significantly and after that remained stable and sustainable. A satisfactory level of confidence among participants had been achieved, in that many felt an increased sense of control over their situation and emotional response to it. Indirectly, these results indicate the success of a team-based prenatal genetic counseling model, which has not been assessed in the literature to date.

Mitochondrial DNA deletion percentage in sun exposed and non sun exposed skin.

PubMed

Powers, Julia M; Murphy, Gillian; Ralph, Nikki; O'Gorman, Susan M; Murphy, James E J

2016-12-01

The percentages of mitochondrial genomes carrying the mtDNA 3895 and the mtDNA 4977 (common) deletion were quantified in sun exposed and non sun exposed skin biopsies, for five cohorts of patients varying either in sun exposure profile, age or skin cancer status. Non-melanoma skin cancer diagnoses are rising in Ireland and worldwide [12] but most risk prediction is based on subjective visual estimations of sun exposure history. A quantitative objective test for pre-neoplastic markers may result in better adherence to sun protective behaviours. Mitochondrial DNA (mtDNA) is known to be subject to the loss of a significant proportion of specific sections of genetic code due to exposure to ultraviolet light in sunlight. Although one such deletion has been deemed more sensitive, another, called the mtDNA 4977 or common deletion, has proved to be a more useful indicator of possible risk in this study. Quantitative molecular analysis was carried out to determine the percentage of genomes carrying the deletion using non sun exposed and sun exposed skin biopsies in cohorts of patients with high or low sun exposure profiles and two high exposure groups undergoing treatment for NMSC. Results indicate that mtDNA deletions correlate to sun exposure; in groups with high sun exposure habits a significant increase in deletion number in exposed over non sun exposed skin occurred. An increase in deletion percentage was also seen in older cohorts compared to the younger group. The mtDNA 3895 deletion was detected in small amounts in exposed skin of many patients, the mtDNA 4977 common deletion, although present to some extent in non sun exposed skin, is suggested to be the more reliable and easily detected marker. In all cohorts except the younger group with relatively lower sun exposure, the mtDNA 4977 deletion was more frequent in sun exposed skin samples compared to non-sun exposed skin. Copyright © 2016 Elsevier B.V. All rights reserved.

Intention to comply with post-exposure management among nurses exposed to blood and body fluids in Taiwan: application of the theory of planned behaviour.

PubMed

Ko, N-Y; Yeh, S-H; Tsay, S-L; Ma, H-J; Chen, C-H; Pan, S-M; Feng, M-C; Chiang, M-C; Lee, Y-W; Chang, L-H; Jang, J-F

2011-04-01

Nurses are at significant risk from occupationally acquired bloodborne virus infections following a needlestick and sharps injury. This study aimed to apply the theory of planned behaviour (TPB) to predict nurses' intention to comply with occupational post-exposure management. A cross-sectional survey was applied to select registered nurses who worked in human immunodeficiency virus (HIV)-designated hospitals. An anonymous, self-administered questionnaire based on the TPB was distributed to 1630 nurses and 1134 (69.5%) questionnaires were returned. From these, a total of 802 nurses (71%) reported blood and body fluid exposure incidents during 2003-2005 and this group was used for analysis. Only 44.6% of the 121 exposed nurses who were prescribed post-exposure prophylaxis (PEP) by infectious disease doctors returned to the clinic for interim monitoring, and only 56.6% of exposed nurses confirmed their final serology status. Structural equation modelling was used to test the TPB indicating perceived behavioural control (the perception of the difficulty or ease of PEP management, β=0.58), subjective norm (the perception of social pressure to adhere to PEP, β=0.15), and attitudes (β=0.12) were significant direct effects on nurses' intention to comply with post-exposure management. The hypothesised model test indicated that the model fitted with the expected relationships and directions of theoretical constructs [χ(2) (14, N=802)=23.14, P=0.057, GFI=0.987, RMSEA=0.039]. The TPB model constructs accounted for 54% of the variance in nurses' intention to comply with post-exposure management. The TPB is an appropriate model for predicting nurses' intention to comply with post-exposure management. Healthcare facilities should have policies to decrease the inconvenience of follow-up to encourage nurses to comply with post-exposure management. Copyright © 2010 the Healthcare Infection Society. Published by Elsevier Ltd. All rights reserved.

Chronic exposure to graphene-based nanomaterials induces behavioral deficits and neural damage in Caenorhabditis elegans.

PubMed

Li, Ping; Xu, Tiantian; Wu, Siyu; Lei, Lili; He, Defu

2017-10-01

Nanomaterials of graphene and its derivatives have been widely applied in recent years, but whose impacts on the environment and health are still not well understood. In the present study, the potential adverse effects of graphite (G), graphite oxide nanoplatelets (GO) and graphene quantum dots (GQDs) on the motor nervous system were investigated using nematode Caenorhabditis elegans as the assay system. After being characterized using TEM, SEM, XPS and PLE, three nanomaterials were chronically exposed to C. elegans for 6 days. In total, 50-100 mg l -1 GO caused a significant reduction in the survival rate, but G and GDDs showed low lethality on nematodes. After chronic exposure of sub-lethal dosages, three nanomaterials were observed to distribute primarily in the pharynx and intestine; but GQDs were widespread in nematode body. Three graphene-based nanomaterials resulted in significant declines in locomotor frequency of body bending, head thrashing and pharynx pumping. In addition, mean speed, bending angle-frequency and wavelength of the crawling movement were significantly reduced after exposure. Using transgenic nematodes, we found high concentrations of graphene-based nanomaterials induced down-expression of dat-1::GFP and eat-4::GFP, but no significant changes in unc-47::GFP. This indicates that graphene-based nanomaterials can lead to damages in the dopaminergic and glutamatergic neurons. The present data suggest that chronic exposure of graphene-based nanomaterials may cause neurotoxicity risks of inducing behavioral deficits and neural damage. These findings provide useful information to understand the toxicity and safe application of graphene-based nanomaterials. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Ethylene dibromide: toxicology and risk assessment.

PubMed

Alexeeff, G V; Kilgore, W W; Li, M Y

1990-01-01

Since the 1920s ethylene dibromide's (EDB's) primary use has been as a scavenger of lead compounds in gasoline. Gasoline evaporation contributed to EDB emissions into the environment. In 1973, the United States Environmental Protection Agency (EPA) issued regulations to reduce the use of leaded gasoline and this has resulted in lower EDB usage and emissions. In addition, EDB has been used extensively as a fumigant since 1948. Its volatility and versatility, based on chemical and biocidal properties, led to its use as a soil sterilant, as a spot fumigant of grain milling machinery, and as a control agent in grain, fruit and vegetable infestations. In 1977 the EPA began a review of EDB's pesticidal uses which eventually led to its cancellation for most agricultural applications. Disposal of EDB and contamination of water supplies remain major environmental concerns. EDB can be absorbed via the dermal, oral and inhalation routes. It appears to be metabolized in vivo by an oxidative pathway (cytochrome P-450) and a conjugation pathway (glutathione S-transferase). The metabolites play an important role in exerting its toxicity. Few human poisonings have been reported from either acute or chronic exposure. However, EDB is irritating to the skin and eyes. Limited information indicates that EDB can damage the liver and kidneys following extensive or prolonged exposure. The genotoxicity of EDB has been clearly demonstrated. It binds to DNA in vivo and in vitro, and a DNA adduct has been identified. EDB has been shown to be mutagenic in numerous bacterial assays, in fungi, in plants, in insects, and in mammalian cell culture. Some evidence indicates that EDB can cause sister chromatid exchange and chromosomal aberrations. EDB is a reproductive toxin, but it does not appear to be teratogenic. It has been shown to affect spermatogenesis in rats, bulls and rams and to affect fertility in fowl. Human studies indicate that EDB exposure may harm sperm and decrease fertility. The toxic effect of greatest concern that may result from EDB exposure is cancer. In rats and mice, EDB produced tumors at the application site and at distant sites. When given orally, EDB has produced tumors in the forestomach, lung, and the circulatory system. When administered by inhalation, EDB produced tumors in the nasal cavity, lung, and the circulatory system. Dermal application of EDB produced skin and lung tumors. Analyses of risks from EDB exposure have focused on potential carcinogenic effects. Initial risk estimates, based on animal studies, indicated that citrus workers had essentially a 100% chance of contracting cancer.(ABSTRACT TRUNCATED AT 400 WORDS)

“Triple M” Effect: A Proposed Mechanism to Explain Increased Dental Amalgam Microleakage after Exposure to Radiofrequency Electromagnetic Radiation

PubMed Central

Mortazavi, Gh.; Mortazavi, S.A.R.; Mehdizadeh, A.R.

2018-01-01

A large body of evidence now indicates that the amount of mercury released from dental amalgam fillings can be significantly accelerated by exposure to radiofrequency electromagnetic fields (RF-EMFs) such as common mobile phones and magnetic resonance imaging (MRI). Studies performed on the increased microleakage of dental amalgam restorations after exposure to RF-EMFs have further supported these findings. Although the accelerated microleakage induced by RF-EMFs is clinically significant, the entire mechanisms of this phenomenon are not clearly understood. In this paper, we introduce “Triple M” effect, a new evidence-based theory which can explain the accelerated microleakage of dental amalgam fillings after exposure to different sources of electromagnetic radiation. Based on this theory, there are saliva-filled tiny spaces between amalgam and the tooth. Exposure of the oral cavity to RF-EMFs increases the energy of these small amounts of saliva. Due to the small mass of saliva in these tiny spaces, a small amount of energy will be required for heating. Moreover, reflection of the radiofrequency radiation on the inner walls of the tiny spaces causes interference which in turn produces some “hot spots” in these spaces. Finally, formation of gas bubbles in response to increased temperature and very rapid expansion of these bubbles will accelerate the microleakage of amalgam. Experiments that confirm the validity of this theory are discussed. PMID:29732349

"Triple M" Effect: A Proposed Mechanism to Explain Increased Dental Amalgam Microleakage after Exposure to Radiofrequency Electromagnetic Radiation.

PubMed

Mortazavi, Gh; Mortazavi, S A R; Mehdizadeh, A R

2018-03-01

A large body of evidence now indicates that the amount of mercury released from dental amalgam fillings can be significantly accelerated by exposure to radiofrequency electromagnetic fields (RF-EMFs) such as common mobile phones and magnetic resonance imaging (MRI). Studies performed on the increased microleakage of dental amalgam restorations after exposure to RF-EMFs have further supported these findings. Although the accelerated microleakage induced by RF-EMFs is clinically significant, the entire mechanisms of this phenomenon are not clearly understood. In this paper, we introduce "Triple M" effect, a new evidence-based theory which can explain the accelerated microleakage of dental amalgam fillings after exposure to different sources of electromagnetic radiation. Based on this theory, there are saliva-filled tiny spaces between amalgam and the tooth. Exposure of the oral cavity to RF-EMFs increases the energy of these small amounts of saliva. Due to the small mass of saliva in these tiny spaces, a small amount of energy will be required for heating. Moreover, reflection of the radiofrequency radiation on the inner walls of the tiny spaces causes interference which in turn produces some "hot spots" in these spaces. Finally, formation of gas bubbles in response to increased temperature and very rapid expansion of these bubbles will accelerate the microleakage of amalgam. Experiments that confirm the validity of this theory are discussed.

Environmental exposure to BDE47 is associated with increased diabetes prevalence: Evidence from community-based case-control studies and an animal experiment

NASA Astrophysics Data System (ADS)

Zhang, Zhan; Li, Shushu; Liu, Lu; Wang, Li; Xiao, Xue; Sun, Zhenzhen; Wang, Xichen; Wang, Chao; Wang, Meilin; Li, Lei; Xu, Qiujin; Gao, Weimin; Wang, Shou-Lin

2016-06-01

Brominated flame retardants exposure has been associated with increasing trends of diabetes and metabolic disease. Thus, the purpose of this study was to provide evidence of polybrominated diphenyl ethers (PBDEs) exposure in relation to diabetes prevalence and to reveal the potential underlying mechanism in epidemiological and animal studies. All the participants received a questionnaire, health examination, and the detection of 7 PBDE congeners in serum in two independent community-based studies from 2011 to 2012 in China. Male rats were exposed to 2,2’4,4’-tetrabromodiphenyl ether (BDE47) for 8 weeks to explore its effects on glucose homeostasis and potential mechanisms using high-throughput genomic analysis. Among the 7 congeners, BDE47 showed significant high detection rate and concentration in cases in Study I and Study II. Every tertile of BDE47 exposure significantly increased the risk of diabetes prevalence in Study I (Ptrend = 0.001) and Study II (Ptrend < 0.001). Additionally, BDE47 treatments induced hyperglycemia in rats. Furthermore, gene microarray analysis showed that diabetes pathway and three gene ontology terms involved in glucose transport were enriched. The results indicated that environmental exposure to BDE47 was associated with increased diabetes prevalence. However, further prospective and mechanistic studies are needed to the causation of diabetes in relation to BDE47.

Use of Threshold of Toxicological Concern (TTC) with High ...

EPA Pesticide Factsheets

Although progress has been made with HTS (high throughput screening) in profiling biological activity (e.g., EPA’s ToxCast™), challenges arise interpreting HTS results in the context of adversity & converting HTS assay concentrations to equivalent human doses for the broad domain of commodity chemicals. Here, we propose using TTC as a risk screening method to evaluate exposure ranges derived from NHANES for 7968 chemicals. Because the well-established TTC approach uses hazard values derived from in vivo toxicity data, relevance to adverse effects is robust. We compared the conservative TTC (non-cancer) value of 90 μg/day (1.5 μg/kg/day) (Kroes et al., Fd Chem Toxicol, 2004) to quantitative exposure predictions of the upper 95% credible interval (UCI) of median daily exposures for 7968 chemicals in 10 different demographic groups (Wambaugh et al., Environ Sci Technol. 48:12760-7, 2014). Results indicate: (1) none of the median values of credible interval of exposure for any chemical in any demographic group was above the TTC; & (2) fewer than 5% of chemicals had an UCI that exceeded the TTC for any group. However, these median exposure predictions do not cover highly exposed (e.g., occupational) populations. Additionally, we propose an expanded risk-based screening workflow that comprises a TTC decision tree that includes screening compounds for structural alerts for DNA reactivity, OPs & carbamates as well as a comparison with bioactivity-based margins of

Time-activity patterns of pregnant women and changes during the course of pregnancy.

PubMed

Nethery, Elizabeth; Brauer, Michael; Janssen, Patti

2009-03-01

Numerous studies suggest that in utero exposures to environmental contaminants are associated with fetal development, congenital anomalies, learning difficulties or other health impacts later in life. Although location and time-activity data have been used to model exposure to specific contaminants in epidemiological studies, little information is available about time-activity patterns of pregnant women. We measured changes in location-based activity patterns over the course of pregnancy (48-h periods, during two or three trimesters) using a self-reported time-activity log among a nonrandom sample of pregnant women (n=62). We assessed the influence of demographics and personal factors on changes in activity over pregnancy using mixed effects regression models. Increasing weeks of pregnancy was a significant predictor for increased time spent at home (1 h/day increase for each trimester of pregnancy), after adjusting for income (2.6 more h/day at home in lowest income group), work status (3.5 more h/day at home for nonworkers) and other children in the family (1.5 more h/day at home with other children). No other measured activities (time outdoors, time in transit modalities or time in other indoor locations) were related to weeks of pregnancy. As our results indicate that pregnant women tend to spend more time at home during the latter stages of pregnancy, future exposure and epidemiological research should consider the potential increase in home-based exposures (i.e., indoor air pollution or chemicals in the home) late in pregnancy, and increased confidence in exposure proxies based on home locations or characteristics during the same period.

Social disparities in heart disease risk and survivor bias among autoworkers: an examination based on survival models and g-estimation.

PubMed

Costello, Sadie; Picciotto, Sally; Rehkopf, David H; Eisen, Ellen A

2015-02-01

To examine gender and racial disparities in ischaemic heart disease (IHD) mortality related to metalworking fluid exposures and in the healthy worker survivor effect. A cohort of white and black men and women autoworkers in the USA was followed from 1941 to 1995 with quantitative exposure to respirable particulate matter from water-based metalworking fluids. Separate analyses used proportional hazards models and g-estimation. The HR for IHD among black men was 3.29 (95% CI 1.49 to 7.31) in the highest category of cumulative synthetic fluid exposure. The HR for IHD among white women exposed to soluble fluid reached 2.44 (95% CI 0.96 to 6.22). However, no increased risk was observed among white men until we corrected for the healthy worker survivor effect. Results from g-estimation indicate that if white male cases exposed to soluble or synthetic fluid had been unexposed to that fluid type, then 1.59 and 1.20 years of life would have been saved on average, respectively. We leveraged the strengths of two different analytic approaches to examine the IHD risks of metalworking fluids. All workers may have the same aetiological risk; however, black and female workers may experience more IHD from water-based metalworking fluid exposure because of a steeper exposure-response or weaker healthy worker survivor effect. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Metabolic Profile as a Potential Modifier of Long-Term Radiation Effects on Peripheral Lymphocyte Subsets in Atomic Bomb Survivors.

PubMed

Yoshida, Kengo; Nakashima, Eiji; Kyoizumi, Seishi; Hakoda, Masayuki; Hayashi, Tomonori; Hida, Ayumi; Ohishi, Waka; Kusunoki, Yoichiro

2016-09-01

Immune system impairments reflected by the composition and function of circulating lymphocytes are still observed in atomic bomb survivors, and metabolic abnormalities including altered blood triglyceride and cholesterol levels have also been detected in such survivors. Based on closely related features of immune and metabolic profiles of individuals, we investigated the hypothesis that long-term effects of radiation exposure on lymphocyte subsets might be modified by metabolic profiles in 3,113 atomic bomb survivors who participated in health examinations at the Radiation Effect Research Foundation, Hiroshima and Nagasaki, in 2000-2002. The lymphocyte subsets analyzed involved T-, B- and NK-cell subsets, and their percentages in the lymphocyte fraction were assessed using flow cytometry. Health examinations included metabolic indicators, body mass index, serum levels of total cholesterol, high-density lipoprotein cholesterol, C-reactive protein and hemoglobin A1c, as well as diabetes and fatty liver diagnoses. Standard regression analyses indicated that several metabolic indicators of obesity/related disease, particularly high-density lipoprotein cholesterol levels, were positively associated with type-1 helper T- and B-cell percentages but were inversely associated with naïve CD4 T and NK cells. A regression analysis adjusted for high-density lipoprotein cholesterol revealed a radiation dose relationship with increasing NK-cell percentage. Additionally, an interaction effect was suggested between radiation dose and C-reactive protein on B-cell percentage with a negative coefficient of the interaction term. Collectively, these findings suggest that radiation exposure and subsequent metabolic profile changes, potentially in relationship to obesity-related inflammation, lead to such long-term alterations in lymphocyte subset composition. Because this study is based on cross-sectional and exploratory analyses, the implications regarding radiation exposure, metabolic profiles and circulating lymphocytes warrant future longitudinal and molecular mechanistic studies.

Risks of carcinogenesis from electromagnetic radiation of mobile telephony devices.

PubMed

Yakymenko, I; Sidorik, E

2010-07-01

Intensive implementation of mobile telephony technology in everyday human life during last two decades has given a possibility for epidemiological estimation of long-term effects of chronic exposure of human organism to low-intensive microwave (MW) radiation. Latest epidemiological data reveal a significant increase in risk of development of some types of tumors in chronic (over 10 years) users of mobile phone. It was detected a significant increase in incidence of brain tumors (glioma, acoustic neuroma, meningioma), parotid gland tumor, seminoma in long-term users of mobile phone, especially in cases of ipsilateral use (case-control odds ratios from 1.3 up to 6.1). Two epidemiological studies have indicated a significant increase of cancer incidence in people living close to the mobile telephony base station as compared with the population from distant area. These data raise a question of adequacy of modern safety limits of electromagnetic radiation (EMR) exposure for humans. For today the limits were based solely on the conception of thermal mechanism of biological effects of RF/MW radiation. Meantime the latest experimental data indicate the significant metabolic changes in living cell under the low-intensive (non-thermal) EMR exposure. Among reproducible biological effects of low-intensive MWs are reactive oxygen species overproduction, heat shock proteins expression, DNA damages, apoptosis. The lack of generally accepted mechanism of biological effects of low-intensive non-ionizing radiation doesn't permit to disregard the obvious epidemiological and experimental data of its biological activity. Practical steps must be done for reasonable limitation of excessive EMR exposure, along with the implementation of new safety limits of mobile telephony devices radiation, and new technological decisions, which would take out the source of radiation from human brain.

Bisphenol A-associated epigenomic changes in prepubescent girls: a cross-sectional study in Gharbiah, Egypt

PubMed Central

2013-01-01

Background There is now compelling evidence that epigenetic modifications link adult disease susceptibility to environmental exposures during specific life stages, including pre-pubertal development. Animal studies indicate that bisphenol A (BPA), the monomer used in epoxy resins and polycarbonate plastics, may impact health through epigenetic mechanisms, and epidemiological data associate BPA levels with metabolic disorders, behavior changes, and reproductive effects. Thus, we conducted an environmental epidemiology study of BPA exposure and CpG methylation in pre-adolescent girls from Gharbiah, Egypt hypothesizing that methylation profiles exhibit exposure-dependent trends. Methods Urinary concentrations of total (free plus conjugated) species of BPA in spot samples were quantified for 60 girls aged 10 to 13. Genome-wide CpG methylation was concurrently measured in bisulfite-converted saliva DNA using the Infinium HumanMethylation27 BeadChip (N = 46). CpG sites from four candidate genes were validated via quantitative bisulfite pyrosequencing. Results CpG methylation varied widely among girls, and higher urinary BPA concentrations were generally associated with less genomic methylation. Based on pathway analyses, genes exhibiting reduced methylation with increasing urinary BPA were involved in immune function, transport activity, metabolism, and caspase activity. In particular, hypomethylation of CpG targets on chromosome X was associated with higher urinary BPA. Using the Comparative Toxicogenomics Database, we identified a number of candidate genes in our sample that previously have been associated with BPA-related expression change. Conclusions These data indicate that BPA may affect human health through specific epigenomic modification of genes in relevant pathways. Thus, epigenetic epidemiology holds promise for the identification of biomarkers from previous exposures and the development of epigenetic-based diagnostic strategies. PMID:23590724

Prioritization of pharmaceuticals based on risks to aquatic environments in Kazakhstan.

PubMed

Aubakirova, Bakhyt; Beisenova, Raikhan; Boxall, Alistair Ba

2017-09-01

Over the last 20 years, there has been increasing interest in the occurrence, fate, effects, and risk of pharmaceuticals in the natural environment. However, we still have only limited or no data on ecotoxicological risks of many of the active pharmaceutical ingredients (APIs) currently in use. This is partly due to the fact that the environmental assessment of an API is an expensive, time-consuming, and complicated process. Prioritization methodologies, which aim to identify APIs of most concern in a particular situation, could therefore be invaluable in focusing experimental work on APIs that really matter. The majority of approaches for prioritizing APIs require annual pharmaceutical usage data. These methods cannot therefore be applied to countries, such as Kazakhstan, that have very limited data on API usage. The present paper therefore offers an approach for prioritizing APIs in surface waters in information-poor regions such as Kazakhstan. Initially data were collected on the number of products and active ingredients for different therapeutic classes in use in Kazakhstan and on the typical doses. These data were then used alongside simple exposure modeling approaches to estimate exposure indices for active ingredients (about 240 APIs) in surface waters in the country. Ecotoxicological effects data were obtained from the literature or predicted. Risk quotients were then calculated for each pharmaceutical based on the exposure and the substances were ranked in order of risk quotient. Highest exposure indices were obtained for benzylpenicillin, metronidazole, sulbactam, ceftriaxone, and sulfamethoxazole. The highest risk was estimated for amoxicillin, clarithromycin, azithromycin, ketoconazole, and benzylpenicillin. In the future, the approach could be employed in other regions where usage information is limited. Integr Environ Assess Manag 2017;13:832-839. © 2017 SETAC. © 2017 SETAC.

Microarray-based bioinformatics analysis of the combined effects of SiNPs and PbAc on cardiovascular system in zebrafish.

PubMed

Hu, Hejing; Zhang, Yannan; Shi, Yanfeng; Feng, Lin; Duan, Junchao; Sun, Zhiwei

2017-10-01

With rapid development of nanotechnology and growing environmental pollution, the combined toxic effects of SiNPs and pollutants of heavy metals like lead have received global attentions. The aim of this study was to explore the cardiovascular effects of the co-exposure of SiNPs and lead acetate (PbAc) in zebrafish using microarray and bioinformatics analysis. Although there was no other obvious cardiovascular malformation except bleeding phenotype, bradycardia, angiogenesis inhibition and declined cardiac output in zebrafish co-exposed of SiNPs and PbAc at NOAEL level, significant changes were observed in mRNA and microRNA (miRNA) expression patterns. STC-GO analysis indicated that the co-exposure might have more toxic effects on cardiovascular system than that exposure alone. Key differentially expressed genes were discerned out based on the Dynamic-gene-network, including stxbp1a, ndfip2, celf4 and gsk3b. Furthermore, several miRNAs obtained from the miRNA-Gene-Network might play crucial roles in cardiovascular disease, such as dre-miR-93, dre-miR-34a, dre-miR-181c, dre-miR-7145, dre-miR-730, dre-miR-129-5p, dre-miR-19d, dre-miR-218b, dre-miR-221. Besides, the analysis of miRNA-pathway-network indicated that the zebrafish were stimulated by the co-exposure of SiNPs and PbAc, which might cause the disturbance of calcium homeostasis and endoplasmic reticulum stress. As a result, cardiac muscle contraction might be deteriorated. In general, our data provide abundant fundamental research clues to the combined toxicity of environmental pollutants and further in-depth verifications are needed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Constraining Landscape History and Glacial Erosivity Using Paired Cosmogenic Nuclides in Upernavik, Northwest Greenland

NASA Technical Reports Server (NTRS)

Corbett, Lee B.; Bierman, Paul R.; Graly, Joseph A.; Neumann, Thomas A.; Rood, Dylan H.

2013-01-01

High-latitude landscape evolution processes have the potential to preserve old, relict surfaces through burial by cold-based, nonerosive glacial ice. To investigate landscape history and age in the high Arctic, we analyzed in situ cosmogenic Be(sup 10) and Al (sup 26) in 33 rocks from Upernavik, northwest Greenland. We sampled adjacent bedrock-boulder pairs along a 100 km transect at elevations up to 1000 m above sea level. Bedrock samples gave significantly older apparent exposure ages than corresponding boulder samples, and minimum limiting ages increased with elevation. Two-isotope calculations Al(sup26)/B(sup 10) on 20 of the 33 samples yielded minimum limiting exposure durations up to 112 k.y., minimum limiting burial durations up to 900 k.y., and minimum limiting total histories up to 990 k.y. The prevalence of BE(sup 10) and Al(sup 26) inherited from previous periods of exposure, especially in bedrock samples at high elevation, indicates that these areas record long and complex surface exposure histories, including significant periods of burial with little subglacial erosion. The long total histories suggest that these high elevation surfaces were largely preserved beneath cold-based, nonerosive ice or snowfields for at least the latter half of the Quaternary. Because of high concentrations of inherited nuclides, only the six youngest boulder samples appear to record the timing of ice retreat. These six samples suggest deglaciation of the Upernavik coast at 11.3 +/- 0.5 ka (average +/- 1 standard deviation). There is no difference in deglaciation age along the 100 km sample transect, indicating that the ice-marginal position retreated rapidly at rates of approx.120 m yr(sup-1).

Early Exposure to Stimulant Medications and Substance-Related Problems: The Role of Medical and Nonmedical Contexts

PubMed Central

McCabe, Sean Esteban; Veliz, Phil; Boyd, Carol J.

2016-01-01

Background The age of onset (early vs. late) and context (medical vs. nonmedical) of exposure to stimulant medications for attention-deficit/hyperactivity disorder (ADHD) have been identified as important factors in the addictive potential of these controlled medications. This study examines the role of medical and nonmedical contexts in the association between early exposure to stimulant medications and substance use and substance-related problems among adolescents. Methods A Web-based survey was self-administered by Detroit-area secondary school students (N = 4,755) between the 2009–10 and 2012–13 school years. The sample consisted of 51% females, 62% Whites, 32% African-Americans, and 6% from other racial categories. Results During the study period, an estimated 11.7% of respondents were ever diagnosed with ADHD. Approximately 6.7% (n = 322) of respondents indicated lifetime medical use of prescription stimulants while 2.6% (n = 124) indicated lifetime nonmedical use. The odds of substance use and substance-related problems were significantly lower among those who initiated earlier medical use of stimulant medications relative to later medical initiation. In contrast, the odds of substance use and substance-related problems were significantly greater among those who initiated earlier nonmedical use of stimulant medications relative to later nonmedical initiation. Conclusions More than one in every ten adolescents in this epidemiologically-derived community-based sample was diagnosed with ADHD. This is the first investigation to demonstrate that context (medical vs. nonmedical) plays a critical role in the relationship between early exposure to stimulant medications and the subsequent risk of substance-related problems during adolescence within the same diverse youth sample. PMID:27129621

Use of butterflies as nontarget insect test species and the acute toxicity and hazard of mosquito control insecticides.

PubMed

Hoang, Tham C; Pryor, Rachel L; Rand, Gary M; Frakes, Robert A

2011-04-01

Honeybees are the standard insect test species used for toxicity testing of pesticides on nontarget insects for the U.S. Environmental Protection Agency (U.S. EPA) under the Federal Insecticide Fungicide and Rodenticide Act (FIFRA). Butterflies are another important insect order and a valued ecological resource in pollination. The current study conducted acute toxicity tests with naled, permethrin, and dichlorvos on fifth larval instar (caterpillars) and adults of different native Florida, USA, butterfly species to determine median lethal doses (24-h LD50), because limited acute toxicity data are available with this major insect group. Thorax- and wing-only applications of each insecticide were conducted. Based on LD50s, thorax and wing application exposures were acutely toxic to both caterpillars and adults. Permethrin was the most acutely toxic insecticide after thorax exposure to fifth instars and adult butterflies. However, no generalization on acute toxicity (sensitivity) of the insecticides could be concluded based on exposures to fifth instars versus adult butterflies or on thorax versus wing exposures of adult butterflies. A comparison of LD50s of the butterflies from this study (caterpillars and adults) with honeybee LD50s for the adult mosquito insecticides on a µg/organism or µg/g basis indicates that several butterfly species are more sensitive to these insecticides than are honeybees. A comparison of species sensitivity distributions for all three insecticides shows that permethrin had the lowest 10th percentile. Using a hazard quotient approach indicates that both permethrin and naled applications in the field may present potential acute hazards to butterflies, whereas no acute hazard of dichlorvos is apparent in butterflies. Butterflies should be considered as potential test organisms when nontarget insect testing of pesticides is suggested under FIFRA. Copyright © 2011 SETAC.

Comprehensive study of the influence of different environments on degradation processes in F8BT: Correlating optoelectronic properties with Raman measurements

NASA Astrophysics Data System (ADS)

Linde, Sivan; Shikler, Rafi

2013-10-01

There is a growing interest in conjugated polymers from both industrial and academic points of views. The reasons are their tunable optoelectronic properties, ease of production, and excellent mechanical properties. However, the ease with which their optoelectronic properties are tunable make devices based on them prone to fast degradation and therefore, short life time. The issue of degradation of organic based optoelectronic devices is the topic of many ongoing researches. However, much less attention is given to degradation processes of the individual components of the devices and their dependence on the environmental conditions. In this work, we report on the degradation of a film of a polyfluorene block copolymer F8BT that is used in a variety of optoelectronic devices under different environments: Sun exposure, heating, and UV exposure in inert and ambient conditions. Degradation was observed in most of the optoelectronic properties of the film. Topographic measurements did not show observable changes of the film morphology following degradation. However, Raman spectroscopy measurements show changes that indicate degradation in one of the building blocks of the copolymer that is associated with electron's conduction. The absolute value of the correlation coefficient between the decrease in the Raman signal and the decrease in the optoelectronic properties is larger than 0.95 under sun exposure it is larger than 0.8 under all other ambient exposures and smaller than 0.65 under inert conditions. These results support the assumption that Oxygen, not necessarily through photo-oxidation, and also water play an important role in the degradation process and indicate the part of the polymer that is most susceptible to degradation.

Asphalt fume exposure levels in North American asphalt production and roofing manufacturing operations.

PubMed

Axten, Charles W; Fayerweather, William E; Trumbore, David C; Mueller, Dennis J; Sampson, Arthur F

2012-01-01

This study extends by 8 years (1998-2005) a previous survey of asphalt fume exposures within North American asphalt processing and roofing product manufacturing workers. It focuses on characterizing personal, full-shift samples and seeks to address several limitations of the previous survey. Five major roofing manufacturers with established occupational health programs submitted workplace asphalt fume sampling results to a central repository for review and analysis. A certified industrial hygienist-led quality assurance team oversaw the data collection, consolidation, and analysis efforts. The analysis dataset consisted of 1261 personal exposure samples analyzed for total particulate (TP) and benzene soluble fraction (BSF) using existing NIOSH methods. For BSF, the survey's arithmetic (0.25 mg/m(3), SD = 0.62) and geometric (0.12 mg/m(3), GSD = 2.88) means indicate that the industry has sustained the control levels achieved in the late 1980s, early 1990s. Similar results were found for TP. The survey-wide summary statistics are consistent with other post-1990 multi-company exposure studies. Although these findings indicate that currently available controls are capable of achieving substantial (95%) compliance with the current threshold limit value in asphalt processing and inorganic shingle and roll plants, they also show that the majority of plants are not achieving this level of exposure control, and that exposures are significantly higher in plants making other product lines, particularly organic felt products. The current retrospective survey of existing company exposure data, like its predecessor, has several important limitations. These include lack of data on smaller manufacturers and on several commercially important product lines; insufficient information on the prevalence and effectiveness of engineering controls; no standard criteria by which to define and assess exposures in non-routine operations; and a paucity of exposure data collected as part of a random sampling strategy. To improve efforts to characterize exposures and potential health risks in roofing plants, a prospective program is currently being developed and piloted with the aim of building a more complete, higher-quality database based on a common industrial hygiene protocol.

Effect-Based Tools for Monitoring and Predicting the Ecotoxicological Effects of Chemicals in the Aquatic Environment

PubMed Central

Connon, Richard E.; Geist, Juergen; Werner, Inge

2012-01-01

Ecotoxicology faces the challenge of assessing and predicting the effects of an increasing number of chemical stressors on aquatic species and ecosystems. Herein we review currently applied tools in ecological risk assessment, combining information on exposure with expected biological effects or environmental water quality standards; currently applied effect-based tools are presented based on whether exposure occurs in a controlled laboratory environment or in the field. With increasing ecological relevance the reproducibility, specificity and thus suitability for standardisation of methods tends to diminish. We discuss the use of biomarkers in ecotoxicology including ecotoxicogenomics-based endpoints, which are becoming increasingly important for the detection of sublethal effects. Carefully selected sets of biomarkers allow an assessment of exposure to and effects of toxic chemicals, as well as the health status of organisms and, when combined with chemical analysis, identification of toxicant(s). The promising concept of “adverse outcome pathways (AOP)” links mechanistic responses on the cellular level with whole organism, population, community and potentially ecosystem effects and services. For most toxic mechanisms, however, practical application of AOPs will require more information and the identification of key links between responses, as well as key indicators, at different levels of biological organization, ecosystem functioning and ecosystem services. PMID:23112741

Influence of S. mutans on base-metal dental casting alloy toxicity.

PubMed

McGinley, E L; Dowling, A H; Moran, G P; Fleming, G J P

2013-01-01

We have highlighted that exposure of base-metal dental casting alloys to the acidogenic bacterium Streptococcus mutans significantly increases cellular toxicity following exposure to immortalized human TR146 oral keratinocytes. With Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), S. mutans-treated nickel-based (Ni-based) and cobalt-chromium-based (Co-Cr-based) dental casting alloys were shown to leach elevated levels of metal ions compared with untreated dental casting alloys. We targeted several biological parameters: cell morphology, viable cell counts, cell metabolic activity, cell toxicity, and inflammatory cytokine expression. S. mutans-treated dental casting alloys disrupted cell morphology, elicited significantly decreased viable cell counts (p < 0.0001) and cell metabolic activity (p < 0.0001), and significantly increased cell toxicity (p < 0.0001) and inflammatory cytokine expression (p < 0.0001). S. mutans-treated Ni-based dental casting alloys induced elevated levels of cellular toxicity compared with S. mutans-treated Co-Cr-based dental casting alloys. While our findings indicated that the exacerbated release of metal ions from S. mutans-treated base-metal dental casting alloys was the likely result of the pH reduction during S. mutans growth, the exact nature of mechanisms leading to accelerated dissolution of alloy-discs is not yet fully understood. Given the predominance of S. mutans oral carriage and the exacerbated cytotoxicity observed in TR146 cells following exposure to S. mutans-treated base-metal dental casting alloys, the implications for the long-term stability of base-metal dental restorations in the oral cavity are a cause for concern.

Fault tree analysis for exposure to refrigerants used for automotive air conditioning in the United States.

PubMed

Jetter, J J; Forte, R; Rubenstein, R

2001-02-01

A fault tree analysis was used to estimate the number of refrigerant exposures of automotive service technicians and vehicle occupants in the United States. Exposures of service technicians can occur when service equipment or automotive air-conditioning systems leak during servicing. The number of refrigerant exposures of service technicians was estimated to be 135,000 per year. Exposures of vehicle occupants can occur when refrigerant enters passenger compartments due to sudden leaks in air-conditioning systems, leaks following servicing, or leaks caused by collisions. The total number of exposures of vehicle occupants was estimated to be 3,600 per year. The largest number of exposures of vehicle occupants was estimated for leaks caused by collisions, and the second largest number of exposures was estimated for leaks following servicing. Estimates used in the fault tree analysis were based on a survey of automotive air-conditioning service shops, the best available data from the literature, and the engineering judgement of the authors and expert reviewers from the Society of Automotive Engineers Interior Climate Control Standards Committee. Exposure concentrations and durations were estimated and compared with toxicity data for refrigerants currently used in automotive air conditioners. Uncertainty was high for the estimated numbers of exposures, exposure concentrations, and exposure durations. Uncertainty could be reduced in the future by conducting more extensive surveys, measurements of refrigerant concentrations, and exposure monitoring. Nevertheless, the analysis indicated that the risk of exposure of service technicians and vehicle occupants is significant, and it is recommended that no refrigerant that is substantially more toxic than currently available substitutes be accepted for use in vehicle air-conditioning systems, absent a means of mitigating exposure.

A passive integrative sampler for mercury vapor in air and neutral mercury species in water

USGS Publications Warehouse

Brumbaugh, W.G.; Petty, J.D.; May, T.W.; Huckins, J.N.

2000-01-01

A passive integrative mercury sampler (PIMS) based on a sealed polymeric membrane was effective for the collection and preconcentration of Hg0. Because the Hg is both oxidized and stabilized in the PIMS, sampling intervals of weeks to months are possible. The effective air sampling rate for a 15 x 2.5 cm device was about 21-equivalents/day (0.002 m3/day) and the detection limit for 4-week sampling was about 2 ng/m3 for conventional ICP-MS determination without clean-room preparation. Sampling precision was ??? 5% RSD for laboratory exposures, and 5-10% RSD for field exposures. These results suggest that the PIMS could be useful for screening assessments of Hg contamination and exposure in the environment, the laboratory, and the workplace. The PIMS approach may be particularly useful for applications requiring unattended sampling for extended periods at remote locations. Preliminary results indicate that sampling for dissolved gaseous mercury (DGM) and potentially other neutral mercury species from water is also feasible. Rigorous validation of the sampler performance is currently in progress. (C) 1999 Elsevier Science Ltd.A passive integrative mercury sampler (PIMS) based on a sealed polymeric membrane was effective for the collection and preconcentration of Hg0. Because the Hg is both oxidized and stabilized in the PIMS, sampling intervals of weeks to months are possible. The effective air sampling rate for a 15??2.5 cm device was about 21-equivalents/day (0.002 m3/day) and the detection limit for 4-week sampling was about 2 ng/m3 for conventional ICP-MS determination without clean-room preparation. Sampling precision was ???5% RSD for laboratory exposures, and 5-10% RSD for field exposures. These results suggest that the PIMS could be useful for screening assessments of Hg contamination and exposure in the environment, the laboratory, and the workplace. The PIMS approach may be particularly useful for applications requiring unattended sampling for extended periods at remote locations. Preliminary results indicate that sampling for dissolved gaseous mercury (DGM) and potentially other neutral mercury species from water is also feasible. Rigorous validation of the sampler performance is currently in progress.

Sensory determinants of valve rhythm dynamics provide in situ biodetection of copper in aquatic environments.

PubMed

Jou, Li-John; Chen, Bo-Ching; Chen, Wei-Yu; Liao, Chung-Min

2016-03-01

This study successfully applied an improved valvometry technique to measure waterborne copper (Cu), based on valve activity dynamics of the freshwater clam Corbicula fluminea. The improved valvometry technique allows the use of free-range bivalves and avoids causing stresses from experimental artifacts. The proposed daily valve rhythm models and a toxicodynamics-based Hill model were linked to predict valve dynamic responses under different Cu exposures with a circadian valve rhythm endpoint. Cu-specific detection threshold was 5.6 (95 % CI 2.1-9.3) and 19.5 (14.6-24.3) μg L(-1) for C. fluminea, based on response times of 300 and 30 min, respectively. Upon exposure to Cu concentrations in excess of 50 μg L(-1), the alteration of valve rhythm behavior was correlated with Cu concentration within 30 min, indicating notable sensing ability. This study outlines the feasibility of an in situ early warning dynamic biomonitoring system for detection of waterborne Cu based on circadian valve activities of C. fluminea.

[Analysis of annual exposure to noise among private farmers according to production profile].

PubMed

Solecki, Leszek

2007-01-01

The objective of the study was the recognition and evaluation of annual exposure to noise among private farmers on selected family farms of three different profiles of agricultural production (plant, animal and mixed). Based on time schedules of agricultural work activities and dosimetric measurements conducted during the whole year, 2 acoustic parameters were determined: total exposure to noise in individual months of the year and equivalent daily exposure to noise. The studies showed that in the case of farms carrying out plant production the highest value of total exposure to noise occurred during the summer-autumn months (July, September, October) and in winter (December, January). On farms of animal production profile the highest values were noted in summer-autumn months (August, October) and winter-spring months (January, March, May, June). On mixed production farms high values occurred in summer-autumn months (August-November) and in April. The distribution of equivalent daily exposure values during the whole year was similar. The results of the study indicated that the greatest noise load occurs on farms carrying out plant and mixed production, whereas the lowest values concerned farms of animal production profile. These values considerably exceed standard values.

Encoded Exposure and Social Norms in Entertainment-Education.

PubMed

Riley, Amy Henderson; Sood, Suruchi; Mazumdar, Paramita Dasgupta; Choudary, Narendra Nath; Malhotra, Alka; Sahba, Naysan

2017-01-01

Entertainment-education is an effective health communication strategy that combines or embeds educational messages into entertainment programs to bring about social and behavior change. For years, scholars have considered how entertainment-education works. Some contemporary theories posit that entertainment-education does not engender behavior change directly but does so through mediating variables. This study adds to the literature on this topic by exploring the direct relationship between exposure and social norms instead of their relationship through behavior as a mediator. Novel to this study is the use of encoded exposure, a continuous and recognition-based measure of exposure that includes ever watching, recall, involvement, and dose in its operationalization. Using cross-sectional data from Kyunki … Jeena Issi Ka Naam Hai, an entertainment-education program in India, this exploratory analysis indicates a positive and significant relationship between encoded exposure and social norms. How can this finding be applied to future programs? Questions remain, and replication is needed, but if it is not essential to go through behavior in order to change social norms, then implications emerge for the theory and practice of entertainment-education.

Cigarette smoke induces mitochondrial metabolic reprogramming in lung cells.

PubMed

Solanki, Hitendra S; Babu, Niraj; Jain, Ankit P; Bhat, Mohd Younis; Puttamallesh, Vinuth N; Advani, Jayshree; Raja, Remya; Mangalaparthi, Kiran K; Kumar, Mahesh M; Prasad, T S Keshava; Mathur, Premendu Prakash; Sidransky, David; Gowda, Harsha; Chatterjee, Aditi

2018-05-01

Cellular transformation owing to cigarette smoking is due to chronic exposure and not acute. However, systematic studies to understand the molecular alterations in lung cells due to cigarette smoke are lacking. To understand these molecular alterations induced by chronic cigarette smoke exposure, we carried out tandem mass tag (TMT) based temporal proteomic profiling of lung cells exposed to cigarette smoke for upto 12months. We identified 2620 proteins in total, of which 671 proteins were differentially expressed (1.5-fold) after 12months of exposure. Prolonged exposure of lung cells to smoke for 12months revealed dysregulation of oxidative phosphorylation and overexpression of enzymes involved in TCA cycle. In addition, we also observed overexpression of enzymes involved in glutamine metabolism, fatty acid degradation and lactate synthesis. This could possibly explain the availability of alternative source of carbon to TCA cycle apart from glycolytic pyruvate. Our data indicates that chronic exposure to cigarette smoke induces mitochondrial metabolic reprogramming in cells to support growth and survival. Copyright © 2017 Elsevier B.V. and Mitochondria Research Society. All rights reserved.

Racial Differences in Perceptions of Air Pollution Health Risk: Does Environmental Exposure Matter?

PubMed Central

Chakraborty, Jayajit; Collins, Timothy W.; Grineski, Sara E.; Maldonado, Alejandra

2017-01-01

This article extends environmental risk perception research by exploring how potential health risk from exposure to industrial and vehicular air pollutants, as well as other contextual and socio-demographic factors, influence racial/ethnic differences in air pollution health risk perception. Our study site is the Greater Houston metropolitan area, Texas, USA—a racially/ethnically diverse area facing high levels of exposure to pollutants from both industrial and transportation sources. We integrate primary household-level survey data with estimates of excess cancer risk from ambient exposure to industrial and on-road mobile source emissions of air toxics obtained from the U.S. Environmental Protection Agency. Statistical analysis is based on multivariate generalized estimation equation models which account for geographic clustering of surveyed households. Our results reveal significantly higher risk perceptions for non-Hispanic Black residents and those exposed to greater cancer risk from industrial pollutants, and also indicate that gender influences the relationship between race/ethnicity and air pollution risk perception. These findings highlight the need to incorporate measures of environmental health risk exposure in future analysis of social disparities in risk perception. PMID:28125059

Movie exposure to smoking cues and adolescent smoking onset: a test for mediation through peer affiliations.

PubMed

Wills, Thomas A; Sargent, James D; Stoolmiller, Mike; Gibbons, Frederick X; Worth, Keilah A; Dal Cin, Sonya

2007-11-01

To determine whether the effect of movie exposure to smoking on adolescent smoking onset is mediated through increased affiliation with peers who smoke. A longitudinal study was conducted with a sample of 5th- 8th graders; persons who were nonsmokers at the baseline assessment (N = 2,614) were followed up 18 months later. Movie exposure to smoking cues was assessed at baseline with a rigorous coding procedure. A school-based survey and follow-up telephone interview determined whether the participant smoked cigarettes. Longitudinal structural modeling analysis indicated movie-smoking exposure was related to smoking onset both through an indirect effect involving increased affiliation with peer smokers and through a direct effect. The analysis controlled for demographics, parenting style, rebelliousness and sensation seeking, school performance, parental smoking, and sibling smoking; several of these variables also had mediated or direct effects to smoking onset. The effect of movie exposure on adolescent smoking onset is attributable in part to a social mechanism. Implications of media effects for prevention are discussed. (PsycINFO Database Record (c) 2007 APA, all rights reserved).

Efficacy and tolerability of Hairgain in individuals with hair loss: a placebo-controlled, double-blind study.

PubMed

Thom, E

2001-01-01

This randomized, placebo-controlled, double-blind study was designed to investigate the efficacy and tolerability of a new agent for the treatment of hair loss, based on a marine protein, minerals and vitamins. Sixty subjects with hair loss of different aetiologies participated in the 6-month blinded phase of the study. Objective assessments indicated that the treatment was effective and subjective assessments showed a statistically significant positive effect of treatment. Exposure to the active preparation for a further 6 months in an open phase indicated a further improvement in hair growth. Exposure of the patients previously treated with placebo to the active preparation for 12 months gave similar results. Tolerability was good and no side-effects were reported. The product investigated may provide an alternative to pharmacotherapy for the treatment of hair-loss problems in individuals with androgenic alopecia.

Impact of Venetoclax Exposure on Clinical Efficacy and Safety in Patients with Relapsed or Refractory Chronic Lymphocytic Leukemia.

PubMed

Freise, Kevin J; Jones, Aksana K; Eckert, Doerthe; Mensing, Sven; Wong, Shekman L; Humerickhouse, Rod A; Awni, Walid M; Salem, Ahmed Hamed

2017-05-01

Venetoclax is a selective, potent, first-in-class B-cell lymphoma-2 inhibitor that restores apoptosis in cancer cells and has demonstrated efficacy in a variety of hematological malignancies. The objective of this research was to characterize the relationship between venetoclax exposures and efficacy and safety in patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). A total of 272 and 338 patients from four clinical studies were pooled for the exposure-efficacy and exposure-safety analyses, respectively. Demographics, baseline disease characteristics, and select co-medications were evaluated for their impact on efficacy (lymphocytes, tumor size, objective response [OR]) and safety (neutropenia and infection). Higher venetoclax concentrations led to a more rapid decrease in lymphocyte counts and tumor size, which translated into patients more rapidly achieving OR. The 17p deletion somatic mutation was not identified, in any of the analyses, to affect the responsiveness of patients to venetoclax. Model-based simulations of lymphocyte counts and tumor size estimated an OR rate (ORR) of 84.8 % (95 % confidence interval 81.5-88.0 %) at a venetoclax dosage of 400 mg daily, with minimal increase in ORR at higher doses. The safety analyses of the adverse events (grade 3 or higher) of neutropenia and infection indicated that higher average venetoclax concentrations were not associated with an increase in adverse events. The exposure-response analyses indicated that a venetoclax dosage regimen of 400 mg daily results in a high (>80 %) probability of achieving OR in R/R CLL/SLL patients, with minimal probability of increasing neutropenia or infection with higher exposures.

Supermarket and fast-food outlet exposure in Copenhagen: associations with socio-economic and demographic characteristics.

PubMed

Svastisalee, Chalida M; Nordahl, Helene; Glümer, Charlotte; Holstein, Bjørn E; Powell, Lisa M; Due, Pernille

2011-09-01

To investigate whether exposure to fast-food outlets and supermarkets is socio-economically patterned in the city of Copenhagen. The study was based on a cross-sectional multivariate approach to examine the association between the number of fast-food outlets and supermarkets and neighbourhood-level socio-economic indicators. Food business addresses were obtained from commercial and public business locators and geocoded using a geographic information system for all neighbourhoods in the city of Copenhagen (n 400). The regression of counts of fast-food outlets and supermarkets v. indicators of socio-economic status (percentage of recent immigrants, percentage without a high-school diploma, percentage of the population under 35 years of age and average household income in Euros) was performed using negative binomial analysis. Copenhagen, Denmark. The unit of analysis was neighbourhood (n 400). In the fully adjusted models, income was not a significant predictor for supermarket exposure. However, neighbourhoods with low and mid-low income were associated with significantly fewer fast-food outlets. Using backwise deletion from the fully adjusted models, low income remained significantly associated with fast-food outlet exposure (rate ratio = 0·66-0·80) in the final model. In the city of Copenhagen, there was no evidence of spatial patterning of supermarkets by income. However, we detected a trend in the exposure to fast-food outlets, such that neighbourhoods in the lowest income quartile had fewer fast-food outlets than higher-income neighbourhoods. These findings have similarities with studies conducted in the UK, but not in the USA. The results suggest there may be socio-economic factors other than income associated with food exposure in Europe.

Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter

USGS Publications Warehouse

Fleck, Jacob A.; Gill, Gary W.; Bergamaschi, Brian A.; Kraus, Tamara E.C.; Downing, Bryan D.; Alpers, Charles N.

2014-01-01

Monomethyl mercury (MeHg) is a potent neurotoxin that threatens ecosystem viability and human health. In aquatic systems, the photolytic degradation of MeHg (photodemethylation) is an important component of the MeHg cycle. Dissolved organic matter (DOM) is also affected by exposure to solar radiation (light exposure) leading to changes in DOM composition that can affect its role in overall mercury (Hg) cycling. This study investigated changes in MeHg concentration, DOM concentration, and the optical signature of DOM caused by light exposure in a controlled field-based experiment using water samples collected from wetlands and rice fields. Filtered water from all sites showed a marked loss in MeHg concentration after light exposure. The rate of photodemethylation was 7.5 × 10-3 m2 mol-1 (s.d. 3.5 × 10-3) across all sites despite marked differences in DOM concentration and composition. Light exposure also caused changes in the optical signature of the DOM despite there being no change in DOM concentration, indicating specific structures within the DOM were affected by light exposure at different rates. MeHg concentrations were related to optical signatures of labile DOM whereas the percent loss of MeHg was related to optical signatures of less labile, humic DOM. Relationships between the loss of MeHg and specific areas of the DOM optical signature indicated that aromatic and quinoid structures within the DOM were the likely contributors to MeHg degradation, perhaps within the sphere of the Hg-DOM bond. Because MeHg photodegradation rates are relatively constant across freshwater habitats with natural Hg–DOM ratios, physical characteristics such as shading and hydrologic residence time largely determine the relative importance of photolytic processes on the MeHg budget in these mixed vegetated and open-water systems.

Alanyl-glutamine dipeptide restores the cytoprotective stress proteome of mesothelial cells exposed to peritoneal dialysis fluids.

PubMed

Kratochwill, Klaus; Boehm, Michael; Herzog, Rebecca; Lichtenauer, Anton Michael; Salzer, Elisabeth; Lechner, Michael; Kuster, Lilian; Bergmeister, Konstantin; Rizzi, Andreas; Mayer, Bernd; Aufricht, Christoph

2012-03-01

Exposure of mesothelial cells to peritoneal dialysis fluids (PDF) results in cytoprotective cellular stress responses (CSR) that counteract PDF-induced damage. In this study, we tested the hypothesis that the CSR may be inadequate in relevant models of peritoneal dialysis (PD) due to insufficient levels of glutamine, resulting in increased vulnerability against PDF cytotoxicity. We particularly investigated the role of alanyl-glutamine (Ala-Gln) dipeptide on the cytoprotective PDF stress proteome. Adequacy of CSR was investigated in two human in vitro models (immortalized cell line MeT-5A and mesothelial cells derived from peritoneal effluent of uraemic patients) following exposure to heat-sterilized glucose-based PDF (PD4-Dianeal, Baxter) diluted with medium and, in a comparative proteomics approach, at different levels of glutamine ranging from depletion (0 mM) via physiological (0.7 mM) to pharmacological levels (8 mM administered as Ala-Gln). Despite severe cellular injury, expression of cytoprotective proteins was dampened upon PDF exposure at physiological glutamine levels, indicating an inadequate CSR. Depletion of glutamine aggravated cell injury and further reduced the CSR, whereas addition of Ala-Gln at pharmacological level restored an adequate CSR, decreasing cellular damage in both PDF exposure systems. Ala-Gln specifically stimulated chaperoning activity, and cytoprotective processes were markedly enhanced in the PDF stress proteome. Taken together, this study demonstrates an inadequate CSR of mesothelial cells following PDF exposure associated with low and physiological levels of glutamine, indicating a new and potentially relevant pathomechanism. Supplementation of PDF with pharmacological doses of Ala-Gln restored the cytoprotective stress proteome, resulting in improved resistance of mesothelial cells to exposure to PDF. Future work will study the clinical relevance of CSR-mediated cytoprotection.

Concurrent photolytic degradation of aqueous methylmercury and dissolved organic matter.

PubMed

Fleck, Jacob A; Gill, Gary; Bergamaschi, Brian A; Kraus, Tamara E C; Downing, Bryan D; Alpers, Charles N

2014-06-15

Monomethyl mercury (MeHg) is a potent neurotoxin that threatens ecosystem viability and human health. In aquatic systems, the photolytic degradation of MeHg (photodemethylation) is an important component of the MeHg cycle. Dissolved organic matter (DOM) is also affected by exposure to solar radiation (light exposure) leading to changes in DOM composition that can affect its role in overall mercury (Hg) cycling. This study investigated changes in MeHg concentration, DOM concentration, and the optical signature of DOM caused by light exposure in a controlled field-based experiment using water samples collected from wetlands and rice fields. Filtered water from all sites showed a marked loss in MeHg concentration after light exposure. The rate of photodemethylation was 7.5×10(-3)m(2)mol(-1) (s.d. 3.5×10(-3)) across all sites despite marked differences in DOM concentration and composition. Light exposure also caused changes in the optical signature of the DOM despite there being no change in DOM concentration, indicating specific structures within the DOM were affected by light exposure at different rates. MeHg concentrations were related to optical signatures of labile DOM whereas the percent loss of MeHg was related to optical signatures of less labile, humic DOM. Relationships between the loss of MeHg and specific areas of the DOM optical signature indicated that aromatic and quinoid structures within the DOM were the likely contributors to MeHg degradation, perhaps within the sphere of the Hg-DOM bond. Because MeHg photodegradation rates are relatively constant across freshwater habitats with natural Hg-DOM ratios, physical characteristics such as shading and hydrologic residence time largely determine the relative importance of photolytic processes on the MeHg budget in these mixed vegetated and open-water systems. Published by Elsevier B.V.

Quantitative weight of evidence assessment of higher tier studies on the toxicity and risks of neonicotinoids in honeybees. 4. Thiamethoxam.

PubMed

Stephenson, Gladys L; Solomon, Keith R

2017-01-01

A quantitative weight of evidence (QWoE) methodology was used to assess several higher-tier studies on the effects of thiamethoxam (TMX) on honeybees. Assessment endpoints were population size and viability of commercially managed honeybee colonies and quantity of hive products. A higher-tier field toxicology study indicated a no-observed-adverse effect concentration (NOAEC) of 29.5 µg TMX/kg syrup, equivalent to an oral no-observed-adverse-effect-dose (NOAED) of 8.6 ng/bee/day for all responses measured. For exposures via deposition of dust, a conservative no-observed-adverse-effect-rate at the level of the colony was 0.1 g TMX/ha. There was minimal risk to honeybees from exposure to TMX via nectar and pollen from its use as a seed-treatment. For exposures via dust and dust/seed applications, there were no concentrations above the risk values for TMX in nectar and pollen. Although some risks were identified for potential exposures via guttation fluid, this route of exposure is incomplete; no apparent adverse effects were observed in field studies. For exposures via dust/seed and dust/foliar applications, few adverse effects were observed. Considering all lines of evidence, the quality of the studies included in this analysis was variable. However, the results of the studies were consistent and point to the same conclusion. The overall weight of evidence based on many studies indicates that TMX has no adverse effects on viability or survival of the colony. Thus, the overall conclusion is that the treatment of seeds with thiamethoxam, as currently used in good agricultural practices, does not present a significant risk to honeybees at the level of the colony.

Psychiatric epidemiologic study of occupational lead exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parkinson, D.K.; Ryan, C.; Bromet, E.J.

1986-02-01

The association of occupational lead exposure with neuropsychiatric functioning was evaluated using data collected in 1982 in eastern Pennsylvania from 288 lead-exposed workers and 181 nonexposed subjects. Both current and cumulative exposure indices were used. After controlling for age, education, and income, few meaningful differences between exposed and control workers were found on either neuropsychologic or psychosocial variables. Dose-response analyses indicated that among lead-exposed workers, cumulative and current exposure were unrelated to neuropsychologic performance. The only meaningful associations occurred between exposure and level of conflict in interpersonal relationships. The results thus give evidence against hypotheses suggesting adverse neuropsychologic effects.

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. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Dietary acrylamide exposure of the French population: results of the second French Total Diet Study.

PubMed

Sirot, Véronique; Hommet, Frédéric; Tard, Alexandra; Leblanc, Jean-Charles

2012-03-01

Acrylamide is a heat-induced carcinogen compound that is found in some foods consequently to cooking or other thermal processes. In the second French Total Diet Study (TDS), acrylamide was analysed in 192 food samples collected in mainland France to be representative of the population diet and prepared "as consumed". Highest mean concentrations were found in potato chips/crisps (954 μg/kg), French fries and other fried potatoes (724 μg/kg), and salted biscuits other than potato chips (697 μg/kg). Exposure of general adult and child populations was assessed by combining analytical results with national consumption data. Mean acrylamide exposure was assessed to be 0.43±0.33 μg/kg of body weight (bw) per day for adults and 0.69±0.58 μg/kg bw/day for children. Although the exposure assessed is lower than in previous evaluations, the calculated margins of exposure, based on benchmark dose limits defined for carcinogenic effects, remain very low especially for young children (below 100 at the 95th percentile of exposure), indicating a health concern. It is therefore advisable to continue efforts in order to reduce dietary exposure to acrylamide. Copyright © 2012 Elsevier Ltd. All rights reserved.

The effect of a multi-axis suspension on whole body vibration exposures and physical stress in the neck and low back in agricultural tractor applications.

PubMed

Kim, Jeong Ho; Dennerlein, Jack T; Johnson, Peter W

2018-04-01

Whole body vibration (WBV) exposures are often predominant in the fore-aft (x) or lateral (y) axis among off-road agricultural vehicles. However, as the current industry standard seats are designed to reduce mainly vertical (z) axis WBV exposures, they may be less effective in reducing drivers' exposure to multi-axial WBV. Therefore, this laboratory-based study aimed to determine the differences between a single-axial (vertical) and multi-axial (vertical + lateral) suspension seat in reducing WBV exposures, head acceleration, self-reported discomfort, and muscle activity (electromyography) of the major muscle of the low back, neck and shoulders. The results showed that the multi-axial suspension seat had significantly lower WBV exposures compared to the single-axial suspension seats (p' < 0.04). Similarly, the multi-axial suspension seat had lower head acceleration and muscle activity of the neck, shoulder, and low back compared to the single-axial suspension seat; some but not all of the differences were statistically significant. These results indicate that the multi-axial suspension seat may reduce the lateral WBV exposures and associated muscular loading in the neck and low back in agricultural vehicle operators. Copyright © 2017 Elsevier Ltd. All rights reserved.

Quantification of nerve agent VX-butyrylcholinesterase adduct biomarker from an accidental exposure.

PubMed

Solano, Maria I; Thomas, Jerry D; Taylor, James T; McGuire, Jeffrey M; Jakubowski, Edward M; Thomson, Sandra A; Maggio, Vincent L; Holland, Kerry E; Smith, J Richard; Capacio, Benedict; Woolfitt, Adrian R; Ashley, David L; Barr, John R

2008-01-01

The lack of data in the open literature on human exposure to the nerve agent O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) gives a special relevance to the data presented in this study in which we report the quantification of VX-butyrylcholinesterase adduct from a relatively low-level accidental human exposure. The samples were analyzed by gas chromatography-high resolution mass spectrometry using the fluoride ion regeneration method for the quantification of multiple nerve agents including VX. Six human plasma samples from the same individual were collected after the patient had been treated once with oxime immediately after exhibiting signs of exposure. Detection limits of approximately 5.5 pg/mL plasma were achieved for the G-analogue of VX (G-VX). Levels of the G-VX ranged from 81.4 pg/mL on the first day after the exposure to 6.9 pg/mL in the sample taken 27 days after the exposure. Based on the reported concentration of human butyrylcholinesterase in plasma of approximately 80 nM, it can be calculated that inhibition levels of >or= 0.05% of BuChE can be accurately quantified. These data further indicate that the fluoride ion regeneration method is a potentially powerful tool that can be used to assess low-level exposure to VX.

Modeling methylene chloride exposure-reduction options for home paint-stripper users.

PubMed

Riley, D M; Small, M J; Fischhoff, B

2000-01-01

Home improvement is a popular activity, but one that can also involve exposure to hazardous substances. Paint stripping is of particular concern because of the high potential exposures to methylene chloride, a solvent that is a potential human carcinogen and neurotoxicant. This article presents a general methodology for evaluating the effectiveness of behavioral interventions for reducing these risks. It doubles as a model that assesses exposure patterns, incorporating user time-activity patterns and risk-mitigation strategies. The model draws upon recent innovations in indoor air-quality modeling to estimate exposure through inhalation and dermal pathways to paint-stripper users. It is designed to use data gathered from home paint-stripper users about room characteristics, amount of stripper used, time-activity patterns and exposure-reduction strategies (e.g., increased ventilation and modification in the timing of stripper application, scraping, and breaks). Results indicate that the effectiveness of behavioral interventions depends strongly on characteristics of the room (e.g., size, number and size of doors and windows, base air-exchange rates). The greatest simple reduction in exposure is achieved by using an exhaust fan in addition to opening windows and doors. These results can help identify the most important information for product labels and other risk-communication materials.