30 CFR 62.130 - Permissible exposure level.

Science.gov (United States)

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Permissible exposure level. 62.130 Section 62... REGULATIONS OCCUPATIONAL NOISE EXPOSURE § 62.130 Permissible exposure level. (a) The mine operator must assure that no miner is exposed during any work shift to noise that exceeds the permissible exposure level. If...

Experimental verification of the imposing principle for maximum permissible levels of multicolor laser radiation

Directory of Open Access Journals (Sweden)

Ivashin V.A.

2013-12-01

Full Text Available Aims. The study presents the results of experimental research to verify the principle overlay for maximum permissible levels (MPL of multicolor laser radiation single exposure on eyes. This principle of the independence of the effects of radiation with each wavelength (the imposing principle, was founded and generalized to a wide range of exposure conditions. Experimental verification of this approach in relation to the impact of laser radiation on tissue fundus of an eye, as shows the analysis of the literature was not carried out. Material and methods. Was used in the experimental laser generating radiation with wavelengths: Л1 =0,532 microns, A2=0,556to 0,562 microns and A3=0,619to 0,621 urn. Experiments were carried out on eyes of rabbits with evenly pigmented eye bottom. Results. At comparison of results of processing of the experimental data with the calculated data it is shown that these levels are close by their parameters. Conclusions. For the first time in the Russian Federation had been performed experimental studies on the validity of multi-colored laser radiation on the organ of vision. In view of the objective coincidence of the experimental data with the calculated data, we can conclude that the mathematical formulas work.

Maximum penetration level of distributed generation without violating voltage limits

NARCIS (Netherlands)

Morren, J.; Haan, de S.W.H.

2009-01-01

Connection of Distributed Generation (DG) units to a distribution network will result in a local voltage increase. As there will be a maximum on the allowable voltage increase, this will limit the maximum allowable penetration level of DG. By reactive power compensation (by the DG unit itself) a

Application of maximum values for radiation exposure and principles for the calculation of radiation doses

International Nuclear Information System (INIS)

2007-08-01

The guide presents the definitions of equivalent dose and effective dose, the principles for calculating these doses, and instructions for applying their maximum values. The limits (Annual Limit on Intake and Derived Air Concentration) derived from dose limits are also presented for the purpose of monitoring exposure to internal radiation. The calculation of radiation doses caused to a patient from medical research and treatment involving exposure to ionizing radiation is beyond the scope of this ST Guide

Galvanizing industry: evaluation of exposure levels using biomonitors

International Nuclear Information System (INIS)

Menezes, Maria Angela de B.C.; Sabino, Claudia de V.S.; Amaral, Angela Maria; Mattos, Silvania V. de M.; S. Filho, Serafim; Maia, Elene Cristina P.

1999-01-01

In Brazil, statistical surveys concerning occupational diseases refer to accidents and damages. The surveys do not refer to the occupational diseases developed through long exposures to hazardous work conditions, involving physical risk and toxic chemical substances. The Program of Medical Control of Occupational Health determines the Maximum Biological Levels Allowed and the Values of Normality References. But concerning metal and toxic inorganic, values of only few elements are established. In Belo Horizonte and surroundings areas, which is an important industrial centre in the country, there are different industries distributed over various areas. There are about 80 galvanizing industries which are responsible for the majority of the metal contamination hospitalities. A preliminary sampling was performed in order to conduct a survey of the exposures to elements related to occupational diseases in galvanizing industry. The preliminary results for toxic and non-toxic elements obtained using hair and fingernails as biomonitors are shown. The K 0 parametric neutron activation analysis method was applied and the elements determined were: Ag, Al, Au, Cl, Co, Cr, Cu, Fe, I, Mn, Na, Ti, V, Ta, and Zn. (author)

Guidelines on radiation exposure levels for emergency situations

International Nuclear Information System (INIS)

1992-07-01

This document provides guidelines for establishing occupational exposure levels for undertaking actions in emergency situations resulting from a nuclear accident. There are three categories of exposed persons identifiable in relation to the circumstances under which they receive exposures resulting from an accident: (i) emergency workers exposed while undertaking urgent corrective actions; (ii) workers exposed while undertaking subsequent remedial actions, including countermeasures to protect the public; (iii) persons living in an environment contaminated by a nuclear accident. Although no dose limit can be easily stated for the first category, doses should be kept below 0.5 Sv. For the second category, normal dose limits would apply with a maximum of 0.05 Sv in a given year; however, in some circumstances where a few key experts are required doses up to 0.1 Sv could be permitted. For the third category the approach to be taken is to apply the ICRP's concept of dose constraint - a fraction of the worker's dose limit, but above the public dose limit. (L.L.) (6 refs., tab.)

Considerations on the establishment of maximum permissible exposure of man

International Nuclear Information System (INIS)

Jacobi, W.

1974-01-01

An attempt is made in the information lecture to give a quantitative analysis of the somatic radiation risk and to illustrate a concept to fix dose limiting values. Of primary importance is the limiting values. Of primary importance is the limiting value of the radiation exposure to the whole population. By consequential application of the risk concept, the following points are considered: 1) Definition of the risk for radiation late damages (cancer, leukemia); 2) relationship between radiation dose and thus caused radiation risk; 3) radiation risk and the dose limiting values at the time; 4) criteria for the maximum acceptable radiation risk; 5) limiting value which can be expected at the time. (HP/LH) [de

The effect of the OSHA lead exposure in construction standard on blood lead levels among iron workers employed in bridge rehabilitation.

Science.gov (United States)

Levin, S M; Goldberg, M; Doucette, J T

1997-03-01

Over 50,000 workers are at risk of occupational exposure to lead in the course of renovating the nation's deteriorating infrastructure. In mid-1993, to control exposure to lead in the construction setting OSHA promulgated a Lead in Construction Standard. In this study, we assessed the effect of the mandated changes in exposure conditions which followed the introduction of this new standard. We analyzed changes in baseline and maximum blood lead concentrations and in maximum increments in blood lead levels before and after introduction of the standard among iron workers employed in the renovation of a large, lead-painted, steel bridge in New York City. Results indicated that baseline and maximum blood lead levels fell significantly after the implementation of the provisions of the standard, as did maximum increments in blood lead concentrations. Seventy-six percent of the workers maintained blood lead concentrations below 20 micrograms/dl after the OSHA standard, as compared with 66% prior to its implementation. Increments of 20 micrograms/dl or more occurred considerably more frequently before introduction of the standard (13% before vs. 4% after; p = 0.01). Evidence of decreased exposure to lead was observed among iron workers who were present both before and after the introduction of the OSHA standard, as well as among iron workers newly hired after the OSHA provisions were put in place. These findings document the effectiveness of the OSHA construction lead standard in controlling exposure to lead in this complex and variable environment. The data indicate the utility of blood lead determinations in assessing the outcome of industrial hygiene interventions to reduce exposures to lead in the construction setting.

Galvanizing industry: evaluation of exposure levels using biomonitors

Energy Technology Data Exchange (ETDEWEB)

Menezes, Maria Angela de B.C.; Sabino, Claudia de V.S.; Amaral, Angela Maria [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN), Belo Horizonte, MG (Brazil); Mattos, Silvania V. de M. [FUNED, Belo Horizonte, MG (Brazil). Div. de Bromatologia e Toxicologia; S. Filho, Serafim [Secretaria Municipal de Saude de Belo Horizonte, MG (Brazil). Coordenacao de Saude do Trabalhador; Maia, Elene Cristina P. [Minas Gerais Univ., Belo Horizonte, MG (Brazil). Dept. de Quimica

1999-11-01

In Brazil, statistical surveys concerning occupational diseases refer to accidents and damages. The surveys do not refer to the occupational diseases developed through long exposures to hazardous work conditions, involving physical risk and toxic chemical substances. The Program of Medical Control of Occupational Health determines the Maximum Biological Levels Allowed and the Values of Normality References. But concerning metal and toxic inorganic, values of only few elements are established. In Belo Horizonte and surroundings areas, which is an important industrial centre in the country, there are different industries distributed over various areas. There are about 80 galvanizing industries which are responsible for the majority of the metal contamination hospitalities. A preliminary sampling was performed in order to conduct a survey of the exposures to elements related to occupational diseases in galvanizing industry. The preliminary results for toxic and non-toxic elements obtained using hair and fingernails as biomonitors are shown. The K{sub 0} parametric neutron activation analysis method was applied and the elements determined were: Ag, Al, Au, Cl, Co, Cr, Cu, Fe, I, Mn, Na, Ti, V, Ta, and Zn. (author) 8 refs., 3 figs., 2 tabs.; e-mail: menezes at urano.cdtn.br

Three-level grid-connected photovoltaic inverter with maximum power point tracking

International Nuclear Information System (INIS)

Tsang, K.M.; Chan, W.L.

2013-01-01

Highlight: ► This paper reports a novel 3-level grid connected photovoltaic inverter. ► The inverter features maximum power point tracking and grid current shaping. ► The inverter can be acted as an active filter and a renewable power source. - Abstract: This paper presents a systematic way of designing control scheme for a grid-connected photovoltaic (PV) inverter featuring maximum power point tracking (MPPT) and grid current shaping. Unlike conventional design, only four power switches are required to achieve three output levels and it is not necessary to use any phase-locked-loop circuitry. For the proposed scheme, a simple integral controller has been designed for the tracking of the maximum power point of a PV array based on an improved extremum seeking control method. For the grid-connected inverter, a current loop controller and a voltage loop controller have been designed. The current loop controller is designed to shape the inverter output current while the voltage loop controller can maintain the capacitor voltage at a certain level and provide a reference inverter output current for the PV inverter without affecting the maximum power point of the PV array. Experimental results are included to demonstrate the effectiveness of the tracking and control scheme.

Basic Restriction and Reference Level in Anatomically-based Japanese Models for Low-Frequency Electric and Magnetic Field Exposures

Science.gov (United States)

Takano, Yukinori; Hirata, Akimasa; Fujiwara, Osamu

Human exposed to electric and/or magnetic fields at low frequencies may cause direct effect such as nerve stimulation and excitation. Therefore, basic restriction is regulated in terms of induced current density in the ICNIRP guidelines and in-situ electric field in the IEEE standard. External electric or magnetic field which does not produce induced quantities exceeding the basic restriction is used as a reference level. The relationship between the basic restriction and reference level for low-frequency electric and magnetic fields has been investigated using European anatomic models, while limited for Japanese model, especially for electric field exposures. In addition, that relationship has not well been discussed. In the present study, we calculated the induced quantities in anatomic Japanese male and female models exposed to electric and magnetic fields at reference level. A quasi static finite-difference time-domain (FDTD) method was applied to analyze this problem. As a result, spatially averaged induced current density was found to be more sensitive to averaging algorithms than that of in-situ electric field. For electric and magnetic field exposure at the ICNIRP reference level, the maximum values of the induced current density for different averaging algorithm were smaller than the basic restriction for most cases. For exposures at the reference level in the IEEE standard, the maximum electric fields in the brain were larger than the basic restriction in the brain while smaller for the spinal cord and heart.

Development of acute exposure guideline levels for airborne exposures to hazardous substances.

Science.gov (United States)

Krewski, Daniel; Bakshi, Kulbir; Garrett, Roger; Falke, Ernest; Rusch, George; Gaylor, David

2004-04-01

Hazardous substances can be released into the atmosphere due to industrial and transportation accidents, fires, tornadoes, earthquakes, and terrorists, thereby exposing workers and the nearby public to potential adverse health effects. Various enforceable guidelines have been set by regulatory agencies for worker and ambient air quality. However, these exposure levels generally are not applicable to rare lifetime acute exposures, which possibly could occur at high concentrations. Acute exposure guideline levels (AEGLs) provide estimates of concentrations for airborne exposures for an array of short durations that possibly could cause mild (AEGL-1), severe, irreversible, potentially disabling adverse health effects (AEGL-2), or life threatening effects (AEGL-3). These levels can be useful for emergency responders and planners in reducing or eliminating potential risks to the public. Procedures and methodologies for deriving AEGLs are reviewed in this paper that have been developed in the United States, with direct input from international representatives of OECD member-countries, by the National Advisory Committee for Acute Exposure Guidelines for Hazardous Substances and reviewed by the National Research Council. Techniques are discussed for the extrapolation of effects across different exposure durations. AEGLs provide a viable approach for assisting in the prevention, planning, and response to acute airborne exposures to toxic agents.

Prenatal exposure to lead in Spain: cord blood levels and associated factors.

Science.gov (United States)

Llop, Sabrina; Aguinagalde, Xabier; Vioque, Jesus; Ibarluzea, Jesús; Guxens, Mònica; Casas, Maribel; Murcia, Mario; Ruiz, María; Amurrio, Ascensión; Rebagliato, Marisa; Marina, Loreto Santa; Fernandez-Somoano, Ana; Tardon, Adonina; Ballester, Ferran

2011-05-01

Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood). A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2μg/dL). A low percentage of cord blood samples with lead levels ≥ 2μg/dL were found (5.9%). Geometric mean and maximum were 1.06μg/dL and 19μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2μg/dL. In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels. Copyright © 2011 Elsevier B.V. All rights reserved.

Exposure levels and determinants of inhalable dust exposure in bakeries.

Science.gov (United States)

Burstyn, I; Teschke, K; Kennedy, S M

1997-12-01

The study's objectives were to measure full-shift exposure to inhalable dust in bakeries and define the determinants of full-shift exposure. Inhalable dust was measured gravimetrically. Ninety-six bakery workers, employed in seven different bakeries, participated in the study. Two side-by-side full-shift inhalable dust samples were obtained from each study participant on a single occasion. Samples were collected on 18 days selected at random. During the entire sampling period, bakers were observed and information on 14 different tasks was recorded at 15 min intervals. Other production characteristics were also recorded for each sampling day. These task and production variables were used in statistical modelling to identify significant predictors of exposure. The mean full-shift inhalable dust exposure was 8.2 mg/m3 (range: 0.1-110 mg/m3). A regression model explained 79% of the variability in exposure. The model indicated that tasks such as weighing, pouring and operating dough-brakers and reversible sheeters increased the exposure, while packing, catching and decorating decreased the exposure. Bread and bun production lines were associated with increased full-shift inhalable dust exposure, while cake production and substitution of dusting with the use of divider oil were associated with decreased exposure. Production tasks and characteristics are strong predictors of personal full-shift exposures to flour dust among bakers; these can be altered to reduce exposure levels.

Long-term exposure to mobile communication radiation: An analysis of time-variability of electric field level in GSM900 down-link channels

International Nuclear Information System (INIS)

Miclaus, S.; Bechet, P.; Gheorghevici, M.

2013-01-01

Interest for knowing long-term human exposure levels due to mobile communications has increased in the last years. It has been shown that short-term exposure assessment made under standard procedural restrictions is not reliable when it comes to conclusions on long-term exposure levels. The present work is the result of a several week analysis of time variability of electric field level inside traffic and control channels of the GSM900 mobile communication down-link band and it indicates that a temporal model to allow future predictions of exposure on the long run is obtainable. Collecting, processing and statistically analysing the data provide expression of the maximum and weighted field strengths and their evolution in time. Specific electromagnetic footprints of the channels have been extracted, differentiations between their characteristics have been emphasised and practical advice is provided, with the scope of contributing to the development of reliable procedures for long-term exposure assessment. (authors)

Effects of high vs low-level radiation exposure

International Nuclear Information System (INIS)

Bond, V.P.

1983-01-01

In order to appreciate adequately the various possible effects of radiation, particularly from high-level vs low-level radiation exposure (HLRE, vs LLRE), it is necessary to understand the substantial differences between (a) exposure as used in exposure-incidence curves, which are always initially linear and without threshold, and (b) dose as used in dose-response curves, which always have a threshold, above which the function is curvilinear with increasing slope. The differences are discussed first in terms of generally familiar nonradiation situations involving dose vs exposure, and then specifically in terms of exposure to radiation, vs a dose of radiation. Examples are given of relevant biomedical findings illustrating that, while dose can be used with HLRE, it is inappropriate and misleading the LLRE where exposure is the conceptually correct measure of the amount of radiation involved

Exposure level of ergonomic risk factors in hotel industries

Science.gov (United States)

Nasrull Abdol Rahman, Mohd; Syahir Muhamad Jaffar, Mohd; Fahrul Hassan, Mohd; Zamani Ngali, Mohd; Pauline, Ong

2017-08-01

Ergonomic Risk Factors (ERFs) which contribute to Musculoskeletal Disorders (MSDs) among room attendants were considered as a problem or trouble since these ERFs would affect their work performance for hotel industries. The purpose of this study was to examine the exposure level of ERFs among room attendants in hotel industries. 65 of respondents were obtained from selected hotels in Peninsular Malaysia. Data were collected by direct observation via Workplace Ergonomic Risk Assessment (WERA) and Quick Exposure Checklist (QEC). There were 36 males and 29 females room attendants involved throughout the research. Most of room attendants experienced high exposure level for back, leg, forceful and vibration based on the exposure level evaluation through WERA while QEC results showed that all room attendants were found to have moderate exposure level for risk factors including back for movement use, shoulders/arms, wrists/hands and neck. All the results obtained showed that the related ERFs for MSDs were associated and essential ergonomic interventions are needed in order to eliminate risk of exposures to MSDs among room attendants in hotel industries.

Prenatal exposure to lead in Spain: Cord blood levels and associated factors

Energy Technology Data Exchange (ETDEWEB)

Llop, Sabrina, E-mail: llop_sab@gva.es [Centre of Public Health Research (CSISP), Av Catalunya 21, 46020, Valencia (Spain); Carlos III Health Institute (ISCIII), 20220 Majadahonda, Madrid (Spain); CIBER de Epidemiologia y Salud Publica (CIBERESP), Doctor Aiguader 88, 8003 Barcelona (Spain); Aguinagalde, Xabier [Public Health Laboratory of Alava, Direccion de Salud Publica, Gobierno Vasco, Santiago 11, 01002, Vitoria-Gasteiz, Basque Country (Spain); Vioque, Jesus [CIBER de Epidemiologia y Salud Publica (CIBERESP), Doctor Aiguader 88, 8003 Barcelona (Spain); Universidad Miguel Hernandez, Av de Alicante KM 87, 03550, Sant Joan d' Alacant (Spain); Ibarluzea, Jesus [CIBER de Epidemiologia y Salud Publica (CIBERESP), Doctor Aiguader 88, 8003 Barcelona (Spain); Departamento de Sanidad Gobierno Vasco, Subdireccion de Salud Publica de Gipuzkoa, Avenida de Navarra 4, 20013 San Sebastian (Spain); Biodonostia, Instituto de Investigacion Biomedica, San Sebastian (Spain); Guxens, Monica [CIBER de Epidemiologia y Salud Publica (CIBERESP), Doctor Aiguader 88, 8003 Barcelona (Spain); Centre for Research of Environmental Epidemiology (CREAL), Doctor Aiguader 88, 8003 Barcelona (Spain); Municipal Institute of Medical Research (IMIM-Hospital del Mar), Doctor Aiguader 88, 8003 Barcelona (Spain); Casas, Maribel [Centre for Research of Environmental Epidemiology (CREAL), Doctor Aiguader 88, 8003 Barcelona (Spain); Municipal Institute of Medical Research (IMIM-Hospital del Mar), Doctor Aiguader 88, 8003 Barcelona (Spain); Murcia, Mario [Centre of Public Health Research (CSISP), Av Catalunya 21, 46020, Valencia (Spain); CIBER de Epidemiologia y Salud Publica (CIBERESP), Doctor Aiguader 88, 8003 Barcelona (Spain); Ruiz, Maria [Centre for Research of Environmental Epidemiology (CREAL), Doctor Aiguader 88, 8003 Barcelona (Spain); Municipal Institute of Medical Research (IMIM-Hospital del Mar), Doctor Aiguader 88, 8003 Barcelona (Spain); and others

2011-05-01

Introduction and Objective: Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood). Methods: A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. {>=} vs < 2 {mu}g/dL). Results: A low percentage of cord blood samples with lead levels {>=} 2 {mu}g/dL were found (5.9%). Geometric mean and maximum were 1.06 {mu}g/dL and 19 {mu}g/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels {>=} 2 {mu}g/dL. Conclusion: In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels. - Research Highlights: {yields} Pb is a ubiquitous environmental pollutant with harmful effects on neurodevelopment. {yields} Cord blood Pb levels in

Prenatal exposure to lead in Spain: Cord blood levels and associated factors

International Nuclear Information System (INIS)

Llop, Sabrina; Aguinagalde, Xabier; Vioque, Jesus; Ibarluzea, Jesus; Guxens, Monica; Casas, Maribel; Murcia, Mario; Ruiz, Maria

2011-01-01

Introduction and Objective: Lead is a known neurotoxic. Fetuses and infants are very vulnerable to lead exposure, since their blood-brain barrier is not completely formed. Hence, there is an importance for monitoring of blood lead levels prenatally and during early infancy. The aim of this study is to evaluate the prenatal exposure to lead and its association with maternal factors in four population based mother-child cohorts in Spain. The present research was carried out within the framework of the INMA project INfancia y Medio Ambiente (Environment and Childhood). Methods: A total of 1462 pregnant women were recruited between 2004 and 2008. Lead was analyzed in a sample of cord blood by thermal decomposition, amalgation, and Atomic Absorption Spectrometry. Maternal sociodemographic, lifestyle and dietary factors were obtained by questionnaires during pregnancy. A multivariate logistic regression model was constructed. The dependent variable was a dichotomous lead level variable (detected vs no detected, i.e. ≥ vs < 2 μg/dL). Results: A low percentage of cord blood samples with lead levels ≥ 2 μg/dL were found (5.9%). Geometric mean and maximum were 1.06 μg/dL and 19 μg/dL, respectively. Smoking at the beginning of pregnancy, age, social class, weight gain during pregnancy, gravidity, and place of residence were the maternal factors associated with detectable cord blood lead levels. Mother's diet does not appear to be a determining factor of lead exposure. Nevertheless, daily intake of iron and zinc may act as a protective factor against having cord blood lead levels ≥ 2 μg/dL. Conclusion: In the different regions of Spain taking part in this study, lead levels to which newborns are exposed are low. Mobilization of lead from bones may be the main contributor to the cord blood levels. - Research Highlights: → Pb is a ubiquitous environmental pollutant with harmful effects on neurodevelopment. → Cord blood Pb levels in Spanish newborn are low in

Overview of the hazards of low-level exposure to radiation

International Nuclear Information System (INIS)

Ritenour, E.R.

1984-01-01

In this chapter the authors are concerned with low-level radiation, doses of ionizing radiations that are ten to thousands of times smaller than those required to contract ARS. Low-level radiation may be defined as an absorbed dose of 10 rem or less delivered over a short period of time. A larger dose delivered over a long period of time, for instance, 50 rem in 10 years, may also be considered low level. The definition is purposely loose so as to cover a wide variety of sources of radiation exposure, such as natural background (100 mrem/year) occupational exposures (<5 rem/year), and medical applications, such as diagnostic radiography (<1 rem). Low-level radiation exposure does not produce ARS. The health effects that may be of concern in regard to low-level radiation are its long-term sequelae. Studies of survivors of high-level radiation exposure (both human and laboratory animals) have indicated that there are three health effects that should be examined at low levels of exposure: induction of cancer, birth abnormalities (from irradiation in utero), and genetic effects. No other long-term effects of low-level exposure have been conclusively demonstrated in animals or humans

Correlation between the results of in vitro and in vivo chromosomal damage tests in consideration of exposure levels of test chemicals.

Science.gov (United States)

Yamamura, Eiji; Aruga, Chinami; Muto, Shigeharu; Baba, Nobuyuki; Uno, Yoshifumi

2018-01-01

We examined the correlation between the results of in vitro and in vivo chromosomal damage tests by using in-house data of 18 pharmaceutical candidates that showed positive results in the in vitro chromosomal aberration or micronucleus test using CHL/IU cells, and quantitatively analyzed them especially in regard to exposure levels of the compounds. Eight compounds showed that the exposure levels [maximum plasma concentration (C max ) and AUC 0-24h ] were comparable with or higher than the in vitro exposure levels [the lowest effective (positive) concentration (LEC) and AUC vitro  = LEC (μg/mL) × treatment time (h)]. Among them, 3 compounds were positive in the in vivo rodent micronucleus assays using bone marrow cells. For 2 compounds, cytotoxicity might produce false-positive results in the in vitro tests. One compound showed in vitro positive results only in the condition with S9 mix which indicated sufficient concentration of unidentified active metabolite(s) might not reach the bone marrow to induce micronuclei. These facts suggested that the in vivo exposure levels being equal to or higher than the in vitro exposure levels might be an important factor to detect in vivo chromosomal damage induced by test chemicals.

HELLE: Health Effects of Low Level Exposures

International Nuclear Information System (INIS)

Schoten, Eert

1998-01-01

The Health Council is closely involved in establishing the scientific foundation of exposure limits for substances and radiation in order to protect public health. Through the years, the Council has contributed to the formulation of principles and procedures, both for carcinogenic and for noncarcinogenic agents. As a rule, the discussion with regard to the derivation of health-based recommended exposure limits centers around the appropriateness of extrapolation methods (What can be inferred from data on high exposure levels and on experimental animals?). Generally speaking, there is a lack of direct information on the health effects of low levels of exposure. Effects at these levels cannot usually be detected by means of traditional animal experiments or epidemiological research. The capacity of these analytical instruments to distinguish between ''signal'' and ''noise'' is inadequate in most cases. Annex B of this report contains a brief outline of the difficulties and the established methods for tackling this problem. In spite of this, the hope exists that the posited weak signals, if they are indeed present, can be detected by other means. The search will have to take place on a deeper level. In other words, effort must be made to discover what occurs at underlying levels of biological organization when organisms are exposed to low doses of radiation or substances. Molecular and cell biology provide various methods and techniques which give an insight into the processes within the cell. This results in an increase in the knowledge about the molecular and cellular effects of exposure to agents, or stated differently, the working mechanisms which form the basis of the health effects. Last year, the Health Council considered that the time was ripe to take stock of the state of knowledge in this field. To this end, an international working conference was held from 19 to 21 October 1997, entitled ''Health Effects of Low Level Exposures: Scientific Developments and

The exposure of Sydney (Australia) to earthquake-generated tsunamis, storms and sea level rise: a probabilistic multi-hazard approach.

Science.gov (United States)

Dall'Osso, F; Dominey-Howes, D; Moore, C; Summerhayes, S; Withycombe, G

2014-12-10

Approximately 85% of Australia's population live along the coastal fringe, an area with high exposure to extreme inundations such as tsunamis. However, to date, no Probabilistic Tsunami Hazard Assessments (PTHA) that include inundation have been published for Australia. This limits the development of appropriate risk reduction measures by decision and policy makers. We describe our PTHA undertaken for the Sydney metropolitan area. Using the NOAA NCTR model MOST (Method for Splitting Tsunamis), we simulate 36 earthquake-generated tsunamis with annual probabilities of 1:100, 1:1,000 and 1:10,000, occurring under present and future predicted sea level conditions. For each tsunami scenario we generate a high-resolution inundation map of the maximum water level and flow velocity, and we calculate the exposure of buildings and critical infrastructure. Results indicate that exposure to earthquake-generated tsunamis is relatively low for present events, but increases significantly with higher sea level conditions. The probabilistic approach allowed us to undertake a comparison with an existing storm surge hazard assessment. Interestingly, the exposure to all the simulated tsunamis is significantly lower than that for the 1:100 storm surge scenarios, under the same initial sea level conditions. The results have significant implications for multi-risk and emergency management in Sydney.

Profiles of noise exposure levels in South African mining

CSIR Research Space (South Africa)

Edwards, A

2011-05-01

Full Text Available were exposed to noise levels of above the 85 dBA legislated occupational exposure level. The conclusion was made that information obtained through the study could be developed into a national personal noise exposure database, including audiometric...

25(OHD3 Levels Relative to Muscle Strength and Maximum Oxygen Uptake in Athletes

Directory of Open Access Journals (Sweden)

Książek Anna

2016-04-01

Full Text Available Vitamin D is mainly known for its effects on the bone and calcium metabolism. The discovery of Vitamin D receptors in many extraskeletal cells suggests that it may also play a significant role in other organs and systems. The aim of our study was to assess the relationship between 25(OHD3 levels, lower limb isokinetic strength and maximum oxygen uptake in well-trained professional football players. We enrolled 43 Polish premier league soccer players. The mean age was 22.7±5.3 years. Our study showed decreased serum 25(OHD3 levels in 74.4% of the professional players. The results also demonstrated a lack of statistically significant correlation between 25(OHD3 levels and lower limb muscle strength with the exception of peak torque of the left knee extensors at an angular velocity of 150°/s (r=0.41. No significant correlations were found between hand grip strength and maximum oxygen uptake. Based on our study we concluded that in well-trained professional soccer players, there was no correlation between serum levels of 25(OHD3 and muscle strength or maximum oxygen uptake.

The Influence of Red Fruit Oil on Creatin Kinase Level at Maximum Physical Activity

Science.gov (United States)

Apollo Sinaga, Fajar; Hotliber Purba, Pangondian

2018-03-01

Heavy physical activities can cause the oxidative stress which resulting in muscle damage with an indicator of elevated levels of Creatin Kinase (CK) enzyme. The oxidative stress can be prevented or reduced by antioxidant supplementation. One of natural resources which contain antioxidant is Red Fruit (Pandanus conoideus) Oil (RFO). This study aims to see the effect of Red Fruit Oil on Creatin Kinase (CK) level at maximum physical activity. This study is an experimental research by using the design of randomized control group pretest-posttest. This study was using 24 male mice divided into four groups, the control group was given aquadest, the treatment groups P1, P2, and P3 were given the RFO orally of 0.15 ml/kgBW, 0.3 ml/kgBW, and 0.6 ml/kgBW, respectively, for a month. The level of CK was checked for all groups at the beginning of study and after the maximum physical activity. The obtained data were then tested statistically by using t-test and ANOVA. The result shows the RFO supplementation during exercise decreased the CK level in P1, P2, and P3 groups with p<0.05, and the higher RFO dosage resulted in decreased CK level at p<0.05. The conclusion of this study is the Red Fruit Oil could decrease the level of CK at maximum physical activity.

Exposure level from selected base station tower around Kuala Nerus

African Journals Online (AJOL)

Health risk due to RF radiation exposure from base station tower (BST) has been debated for years leading to public concerns. Thus, this preliminary study aims to measure, evaluate and analyze the exposure level on three selected BST around Kuala Nerus. The measurement of exposure level in terms of voltage ...

The effects of pre-natal-, early-life- and indirectly-initiated exposures to maximum adversities on the course of schizophrenia.

Science.gov (United States)

Levine, Stephen Z; Levav, Itzhak; Yoffe, Rinat; Pugachova, Inna

2014-09-01

The effects of pre-natal-, early-life- and indirectly-initiated exposures to protracted maximum adversity on the course of schizophrenia are unknown. To compare the aforementioned Holocaust directly exposed subgroups with an indirectly exposed subgroup on the course of schizophrenia. The study population were: Israeli Jews in-uterus or born in Nazi-occupied or dominated European nations by the end of the persecution of the Jews, who were alive in 1950, and who had a last discharge diagnosis of schizophrenia in the Israel National Psychiatric Case Registry by 2013 (N=4933). The population was disaggregated into subgroups who (1) migrated after WWII and who had (1a) pre-natal (n=584, 11.8%) and (1b) early-life (n=3709, 75.2%) initiated exposures to the maximum adversities of the Holocaust, and (2) indirectly exposed individuals to the Holocaust who migrated before the Nazi-era persecution begun (n=640, 13%). Recurrent event survival analyses were computed to examine the psychiatric re-hospitalization risk of the study subgroups, unadjusted and adjusted for age of onset of the disorder and sex. The pre-natal initiated exposure subgroup had a significantly (pPoland-born individuals, the years 1922 and 1935; and followed at least 10 years and to the year 2000. Pre-natal initiated exposure to the maximal adversity of the holocaust constitutes a consistent risk factor for a worse course of schizophrenia, a possible byproduct of neurodevelopment disruptions induced by maternal stress and/or famine and/or infections. Copyright © 2014 Elsevier B.V. All rights reserved.

Levels of 131I Activity in Patients to Enable Hospital Discharge, Based on External Exposure of Family Members of the Patient in Japan

International Nuclear Information System (INIS)

Koshida, K.; Nishizawa, K.; Koga, S.; Orito, T.

1999-01-01

The activity levels for discharge from hospital of patients treated with 131 I in Japan are described. The level was determined by considering the public annual dose limit in Japan of 1 mSv and the possible exposure of family members with whom the patients were in daily contact. All analyses are based on a partner, where both the partner and the children will be subject to exposure. The external exposure was calculated by using the data on the distance between the patient and family members, the length of the time spent at each distance, and each member's age. It was assumed that the mother must continue to take responsibility for care of children during the period that she is radioactive. The conclusions of this work are that a maximum residual 131 I radioactivity of <97 MBq, with a distance from the patient in bed greater than 50 cm and the ages of patient's children all over 1 year, will be required to ensure that the maximum dose to any contact will not exceed 1 mSv. More than 50 cm distance suggests either an unmarried housewife or the partner sleeping in an adjacent room or twin beds. No restriction is needed in respect of external exposure for patients with residual radioactivity of 42 MBq, although levels lower than this may be required where there is a risk of contamination, e.g. due to urinary incontinence. This conflicts with recommended activity levels for discharge (ICRP 25) of 560 MBq (for a dose limit of 5 mSv). The findings of this work are only directly relevant for the age range under 55 years. No account was taken in this paper of internal exposure from internal pathways. (author)

Pilot survey of subway and bus stop noise levels.

Science.gov (United States)

Gershon, Robyn R M; Neitzel, Richard; Barrera, Marissa A; Akram, Muhammad

2006-09-01

Excessive noise exposure is a serious global urban health problem, adversely affecting millions of people. One often cited source of urban noise is mass transit, particularly subway systems. As a first step in determining risk within this context, we recently conducted an environmental survey of noise levels of the New York City transit system. Over 90 noise measurements were made using a sound level meter. Average and maximum noise levels were measured on subway platforms, and maximum levels were measured inside subway cars and at several bus stops for comparison purposes. The average noise level measured on the subway platforms was 86 +/- 4 dBA (decibel-A weighting). Maximum levels of 106, 112, and 89 dBA were measured on subway platforms, inside subway cars, and at bus stops, respectively. These results indicate that noise levels in subway and bus stop environments have the potential to exceed recommended exposure guidelines from the World Health Organization (WHO) and U.S. Environmental Protection Agency (EPA), given sufficient exposure duration. Risk reduction strategies following the standard hierarchy of control measures should be applied, where feasible, to reduce subway noise exposure.

Levels of {sup 131}I Activity in Patients to Enable Hospital Discharge, Based on External Exposure of Family Members of the Patient in Japan

Energy Technology Data Exchange (ETDEWEB)

Koshida, K.; Nishizawa, K.; Koga, S.; Orito, T

1999-07-01

The activity levels for discharge from hospital of patients treated with {sup 131}I in Japan are described. The level was determined by considering the public annual dose limit in Japan of 1 mSv and the possible exposure of family members with whom the patients were in daily contact. All analyses are based on a partner, where both the partner and the children will be subject to exposure. The external exposure was calculated by using the data on the distance between the patient and family members, the length of the time spent at each distance, and each member's age. It was assumed that the mother must continue to take responsibility for care of children during the period that she is radioactive. The conclusions of this work are that a maximum residual {sup 131}I radioactivity of <97 MBq, with a distance from the patient in bed greater than 50 cm and the ages of patient's children all over 1 year, will be required to ensure that the maximum dose to any contact will not exceed 1 mSv. More than 50 cm distance suggests either an unmarried housewife or the partner sleeping in an adjacent room or twin beds. No restriction is needed in respect of external exposure for patients with residual radioactivity of 42 MBq, although levels lower than this may be required where there is a risk of contamination, e.g. due to urinary incontinence. This conflicts with recommended activity levels for discharge (ICRP 25) of 560 MBq (for a dose limit of 5 mSv). The findings of this work are only directly relevant for the age range under 55 years. No account was taken in this paper of internal exposure from internal pathways. (author)

Radiation exposure and radon levels in some stations of the Syrian gas company

International Nuclear Information System (INIS)

Al-Masri, M. S.; Shwekani, R.; Jerbi, B.; Awad, I.

2006-06-01

In the present study, exposure levels and radon concentrations have been measured in natural gas production lines at the Syrian gas company. The study area includes gas stations for directories of Der Ezzor, Al-Jbessa, Al-Hassaka, and the middle region. The results showed that radiation exposure rates in remote stations and internal stations were within the natural levels except for two main locations, viz reflex pumps and propane production unites; 3 μSvhr -1 was reported. Radon concentration in Syrian natural gas varied between 15.4 Bqm - 3 and 1141 Bqm - 3; coproduced natural gas was found to contain higher concentration that the free natural gas. In addition, radon concentrations were higher in the central processing facilities that the well heads; these high levels are due to pressurizing and concentrating processes that enhance radon gas and its daughters concentrations in these stations. Moreover, a value of 659 Bqm - 3 in Al-Jbessa directorate gas and 225 Bqm - 3 in Al-Hassaka directorate gas were reported. While the concentration was lower in gas producing safur; a value of 80 Bqm - 3 was observed. On the other hand, maximum radon gas concentrations and its daughters in workplace air environment was found to be relatively high in the gas analysis laboratory and they are due to gas release inside the lab during analysis in addition to good separation of these laboratories from the surrounding environment. (author)

Quantile-based Bayesian maximum entropy approach for spatiotemporal modeling of ambient air quality levels.

Science.gov (United States)

Yu, Hwa-Lung; Wang, Chih-Hsin

2013-02-05

Understanding the daily changes in ambient air quality concentrations is important to the assessing human exposure and environmental health. However, the fine temporal scales (e.g., hourly) involved in this assessment often lead to high variability in air quality concentrations. This is because of the complex short-term physical and chemical mechanisms among the pollutants. Consequently, high heterogeneity is usually present in not only the averaged pollution levels, but also the intraday variance levels of the daily observations of ambient concentration across space and time. This characteristic decreases the estimation performance of common techniques. This study proposes a novel quantile-based Bayesian maximum entropy (QBME) method to account for the nonstationary and nonhomogeneous characteristics of ambient air pollution dynamics. The QBME method characterizes the spatiotemporal dependence among the ambient air quality levels based on their location-specific quantiles and accounts for spatiotemporal variations using a local weighted smoothing technique. The epistemic framework of the QBME method can allow researchers to further consider the uncertainty of space-time observations. This study presents the spatiotemporal modeling of daily CO and PM10 concentrations across Taiwan from 1998 to 2009 using the QBME method. Results show that the QBME method can effectively improve estimation accuracy in terms of lower mean absolute errors and standard deviations over space and time, especially for pollutants with strong nonhomogeneous variances across space. In addition, the epistemic framework can allow researchers to assimilate the site-specific secondary information where the observations are absent because of the common preferential sampling issues of environmental data. The proposed QBME method provides a practical and powerful framework for the spatiotemporal modeling of ambient pollutants.

An Iterative Maximum a Posteriori Estimation of Proficiency Level to Detect Multiple Local Likelihood Maxima

Science.gov (United States)

Magis, David; Raiche, Gilles

2010-01-01

In this article the authors focus on the issue of the nonuniqueness of the maximum likelihood (ML) estimator of proficiency level in item response theory (with special attention to logistic models). The usual maximum a posteriori (MAP) method offers a good alternative within that framework; however, this article highlights some drawbacks of its…

Human exposure to low level ionising radiation

International Nuclear Information System (INIS)

Paix, David

1988-01-01

This paper describes the low-level radiation sources and their effects on human populations, from a global perspective. 'Low-level' means exposures in the range of the natural background to which everybody is exposed. The quoted values are whole-world averages, but individual variations are mentioned in a few cases. (author). 22 refs

Multi-level restricted maximum likelihood covariance estimation and kriging for large non-gridded spatial datasets

KAUST Repository

Castrillon, Julio; Genton, Marc G.; Yokota, Rio

2015-01-01

We develop a multi-level restricted Gaussian maximum likelihood method for estimating the covariance function parameters and computing the best unbiased predictor. Our approach produces a new set of multi-level contrasts where the deterministic

Theoretical assessment of the maximum obtainable power in wireless power transfer constrained by human body exposure limits in a typical room scenario.

Science.gov (United States)

Chen, Xi Lin; De Santis, Valerio; Umenei, Aghuinyue Esai

2014-07-07

In this study, the maximum received power obtainable through wireless power transfer (WPT) by a small receiver (Rx) coil from a relatively large transmitter (Tx) coil is numerically estimated in the frequency range from 100 kHz to 10 MHz based on human body exposure limits. Analytical calculations were first conducted to determine the worst-case coupling between a homogeneous cylindrical phantom with a radius of 0.65 m and a Tx coil positioned 0.1 m away with the radius ranging from 0.25 to 2.5 m. Subsequently, three high-resolution anatomical models were employed to compute the peak induced field intensities with respect to various Tx coil locations and dimensions. Based on the computational results, scaling factors which correlate the cylindrical phantom and anatomical model results were derived. Next, the optimal operating frequency, at which the highest transmitter source power can be utilized without exceeding the exposure limits, is found to be around 2 MHz. Finally, a formulation is proposed to estimate the maximum obtainable power of WPT in a typical room scenario while adhering to the human body exposure compliance mandates.

Theoretical assessment of the maximum obtainable power in wireless power transfer constrained by human body exposure limits in a typical room scenario

International Nuclear Information System (INIS)

Chen, Xi Lin; De Santis, Valerio; Umenei, Aghuinyue Esai

2014-01-01

In this study, the maximum received power obtainable through wireless power transfer (WPT) by a small receiver (Rx) coil from a relatively large transmitter (Tx) coil is numerically estimated in the frequency range from 100 kHz to 10 MHz based on human body exposure limits. Analytical calculations were first conducted to determine the worst-case coupling between a homogeneous cylindrical phantom with a radius of 0.65 m and a Tx coil positioned 0.1 m away with the radius ranging from 0.25 to 2.5 m. Subsequently, three high-resolution anatomical models were employed to compute the peak induced field intensities with respect to various Tx coil locations and dimensions. Based on the computational results, scaling factors which correlate the cylindrical phantom and anatomical model results were derived. Next, the optimal operating frequency, at which the highest transmitter source power can be utilized without exceeding the exposure limits, is found to be around 2 MHz. Finally, a formulation is proposed to estimate the maximum obtainable power of WPT in a typical room scenario while adhering to the human body exposure compliance mandates. (paper)

Application of maximum values for radiation exposure and principles for the calculation of radiation dose

International Nuclear Information System (INIS)

2000-01-01

The guide sets out the mathematical definitions and principles involved in the calculation of the equivalent dose and the effective dose, and the instructions concerning the application of the maximum values of these quantities. further, for monitoring the dose caused by internal radiation, the guide defines the limits derived from annual dose limits (the Annual Limit on Intake and the Derived Air Concentration). Finally, the guide defines the operational quantities to be used in estimating the equivalent dose and the effective dose, and also sets out the definitions of some other quantities and concepts to be used in monitoring radiation exposure. The guide does not include the calculation of patient doses carried out for the purposes of quality assurance

Application of maximum values for radiation exposure and principles for the calculation of radiation dose

Energy Technology Data Exchange (ETDEWEB)

NONE

2000-07-01

The guide sets out the mathematical definitions and principles involved in the calculation of the equivalent dose and the effective dose, and the instructions concerning the application of the maximum values of these quantities. further, for monitoring the dose caused by internal radiation, the guide defines the limits derived from annual dose limits (the Annual Limit on Intake and the Derived Air Concentration). Finally, the guide defines the operational quantities to be used in estimating the equivalent dose and the effective dose, and also sets out the definitions of some other quantities and concepts to be used in monitoring radiation exposure. The guide does not include the calculation of patient doses carried out for the purposes of quality assurance.

Evaluation of noise pollution level based upon community exposure and response data

Science.gov (United States)

Edmiston, R. D.

1972-01-01

The results and procedures are reported from an evaluation of noise pollution level as a predictor of annoyance, based on aircraft noise exposure and community response data. The measures of noise exposure presented include composite noise rating, noise exposure forecast, noise and number index. A proposed measure as a universal noise exposure measure for noise pollution level (L sub NP) is discussed.

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

International Nuclear Information System (INIS)

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

2000-01-01

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

On the assessment of shooting sounds : Loudness-level weightings versus A- and C-weighted sound exposure levels (L)

NARCIS (Netherlands)

Vos, J.; Geurtsen, F.W.M.

2003-01-01

As an alternative to the A-weighted sound exposure level (ASEL) Schomer et al. [J. Acoust. Soc. Am. 110, 2390-2397 (2001)] used the equal-loudness level contours as a dynamic filter to determine the loudness-level-weighted sound exposure level (LLSEL). From their analyses they concluded that the

Ambient and at-the-ear occupational noise exposure and serum lipid levels

DEFF Research Database (Denmark)

Arlien-Søborg, Mai C; Schmedes, Astrid S; Stokholm, Z A

2016-01-01

-the-ear occupational noise exposure and serum levels of total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol, and triglycerides when accounting for well-established predictors of lipid levels. METHODS: This cross-sectional study included 424 industrial workers and 84 financial......OBJECTIVES: Occupational and residential noise exposure has been related to increased risk of cardiovascular disease. Alteration of serum lipid levels has been proposed as a possible causal pathway. The objective of this study was to investigate the relation between ambient and at...... workers to obtain contrast in noise exposure levels. They provided a serum sample and wore portable dosimeters that every 5-s recorded ambient noise exposure levels during a 24-h period. We extracted measurements obtained during work and calculated the full-shift mean ambient noise level. For 331 workers...

Population-Level Exposure to Particulate Air Pollution during Active Travel: Planning for Low-Exposure, Health-Promoting Cities.

Science.gov (United States)

Hankey, Steve; Lindsey, Greg; Marshall, Julian D

2017-04-01

Providing infrastructure and land uses to encourage active travel (i.e., bicycling and walking) are promising strategies for designing health-promoting cities. Population-level exposure to air pollution during active travel is understudied. Our goals were a ) to investigate population-level patterns in exposure during active travel, based on spatial estimates of bicycle traffic, pedestrian traffic, and particulate concentrations; and b ) to assess how those exposure patterns are associated with the built environment. We employed facility-demand models (active travel) and land use regression models (particulate concentrations) to estimate block-level ( n = 13,604) exposure during rush-hour (1600-1800 hours) in Minneapolis, Minnesota. We used the model-derived estimates to identify land use patterns and characteristics of the street network that are health promoting. We also assessed how exposure is correlated with indicators of health disparities (e.g., household income, proportion of nonwhite residents). Our work uses population-level rates of active travel (i.e., traffic flows) rather than the probability of walking or biking (i.e., "walkability" or "bikeability") to assess exposure. Active travel often occurs on high-traffic streets or near activity centers where particulate concentrations are highest (i.e., 20-42% of active travel occurs on blocks with high population-level exposure). Only 2-3% of blocks (3-8% of total active travel) are "sweet spots" (i.e., high active travel, low particulate concentrations); sweet spots are located a ) near but slightly removed from the city-center or b ) on off-street trails. We identified 1,721 blocks (~ 20% of local roads) where shifting active travel from high-traffic roads to adjacent low-traffic roads would reduce exposure by ~ 15%. Active travel is correlated with population density, land use mix, open space, and retail area; particulate concentrations were mostly unchanged with land use. Public health officials and

Secondhand smoke exposure and serum cotinine levels among current smokers in the USA.

Science.gov (United States)

Lindsay, Ryan P; Tsoh, Janice Y; Sung, Hai-Yen; Max, Wendy

2016-03-01

Secondhand smoke (SHS) likely provides additional exposure to nicotine and toxins for smokers, but has been understudied. Our objective was to determine whether SHS exposure among smokers yields detectable differences in cotinine levels compared with unexposed smokers at the population level. Using the US National Health and Nutrition Examination Survey (NHANES) for the years 1999-2012, we compared serum cotinine levels of 4547 current adult cigarette smokers stratified by self-reported SHS exposure sources (home and/or work) and smoking intensity. A weighted multivariable linear regression model determined the association between SHS exposure and cotinine levels among smokers. Smokers with SHS exposure at home (43.8%) had higher cotinine levels (β=0.483, p≤0.001) compared with those with no SHS exposure at home after controlling for the number of cigarettes smoked per day and number of days smoked in the previous 5 days, survey year, age, gender and education. Smokers with SHS exposure at work (20.0%) did not have significantly higher cotinine levels after adjustment. The adjusted geometric mean cotinine levels of light smokers (1-9 cigarettes per day) with no SHS exposure, exposure at work only, home only, and both home and work were 52.0, 62.7, 67.2, 74.4 ng/mL, respectively, compared with 219.4, 220.9, 255.2, 250.5 ng/mL among moderate/heavy smokers (≥10 cigarettes per day). Smokers living in residences where others smoke inside the home had significantly higher cotinine levels than smokers reporting no SHS exposure, regardless of individual smoking intensity. Future research should target the role that SHS exposure may have in nicotine dependence, cessation outcomes and other health impacts among smokers. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Standing operating procedures for developing acute exposure guideline levels for hazardous chemicals

National Research Council Canada - National Science Library

National Research Council (U.S.). Subcommittee on Acute Exposure Guideline Levels

2001-01-01

Standing Operating Procedures for Developing Acute Exposure Guideline Levels for Hazardous Chemicals contains a detailed and comprehensive methodology for developing acute exposure guideline levels (AEGLs...

Aircrew radiation exposure assessment for Yugoslav airlines

Energy Technology Data Exchange (ETDEWEB)

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

1997-12-31

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

Estimating the risk of bladder and kidney cancer from exposure to low-levels of arsenic in drinking water, Nova Scotia, Canada.

Science.gov (United States)

Saint-Jacques, Nathalie; Brown, Patrick; Nauta, Laura; Boxall, James; Parker, Louise; Dummer, Trevor J B

2018-01-01

Arsenic in drinking water impacts health. Highest levels of arsenic have been historically observed in Taiwan and Bangladesh but the contaminant has been affecting the health of people globally. Strong associations have been confirmed between exposure to high-levels of arsenic in drinking water and a wide range of diseases, including cancer. However, at lower levels of exposure, especially near the current World Health Organization regulatory limit (10μg/L), this association is inconsistent as the effects are mostly extrapolated from high exposure studies. This ecological study used Bayesian inference to model the relative risk of bladder and kidney cancer at these lower concentrations-0-2μg/L; 2-5μg/L and; ≥5μg/L of arsenic-in 864 bladder and 525 kidney cancers diagnosed in the study area, Nova Scotia, Canada between 1998 and 2010. The model included proxy measures of lifestyle (e.g. smoking) and accounted for spatial dependencies. Overall, bladder cancer risk was 16% (2-5μg/L) and 18% (≥5μg/L) greater than that of the referent group (water arsenic-levels within the current the World Health Organization maximum acceptable concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Polychlorinated biphenyl exposure and corticosterone levels in seven polar seabird species

International Nuclear Information System (INIS)

Tartu, S.; Angelier, F.; Bustnes, J.O.; Moe, B.; Hanssen, S.A.; Herzke, D.; Gabrielsen, G.W.; Verboven, N.; Verreault, J.; Labadie, P.; Budzinski, H.; Wingfield, J.C.

2015-01-01

The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorly investigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Some studies have suggested that environmental exposure to PCBs and altered CORT secretion might be associated. Here we investigated the relationships between blood PCB concentrations and circulating CORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hence covering a wide range of PCB exposure. Blood ∑ 7 PCB concentrations (range: 61–115,632 ng/g lw) were positively associated to baseline or stress-induced CORT levels in three species and negatively associated to stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levels generally increase with increasing blood ∑ 7 PCB concentrations, whereas stress-induced CORT levels decrease when reaching high blood ∑ 7 PCB concentrations. This study suggests that the nature of the PCB-CORT relationships may depend on the level of PCB exposure. - Highlights: • Relationships between PCBs and stress hormones (CORT) are not well known in birds. • We measured blood PCBs, baseline and stress-induced CORT in seven seabird species. • ∑PCB was positively associated to baseline or stress-induced CORT in three species. • ∑PCBs was negatively linked to stress-induced CORT in the most contaminated species. • The nature of the PCB-CORT relationships may depend on the level of PCB exposure. - In polar seabird species, the relationship between PCB and CORT concentrations may be related to the levels of contamination

Aggregate-level lead exposure, gun violence, homicide, and rape.

Science.gov (United States)

Boutwell, Brian B; Nelson, Erik J; Qian, Zhengmin; Vaughn, Michael G; Wright, John P; Beaver, Kevin M; Barnes, J C; Petkovsek, Melissa; Lewis, Roger; Schootman, Mario; Rosenfeld, Richard

2017-01-01

An increasing body of research has linked the geographic distribution of lead with various indicators of criminal and antisocial behavior. The current study, using data from an ongoing project related to lead exposure in St. Louis City, MO, analyzed the association between aggregate blood lead levels and specific indicators violent crime within the city. Ecological study. St. Louis, Missouri. Blood lead levels. Official reports of violent crimes were categorized as 1) crimes involving a firearm (yes/no), 2) assault crimes (with or without a firearm), 3) robbery crimes (with or without a firearm), 4) homicides and 5) rape. With the exception of rape, aggregate blood-lead levels were statistically significant predictors of violent crime at the census tract level. The risk ratios for each of the outcome measures were as follows: firearm crimes 1.03 (1.03-1.04), assault crimes 1.03 (1.02-1.03), robbery crimes 1.03 (1.02-1.04), homicide 1.03 (1.01, 1.04), and rape 1.01 (0.99-1.03). Extending prior research in St. Louis, results suggest that aggregated lead exposure at the census tract level predicted crime outcomes, even after accounting for important sociological variables. Moving forward, a more developed understanding of aggregate level crime may necessitate a shift toward studying the synergy between sociological and biological risk factors such as lead exposure.

Televised Antismoking Advertising: Effects of Level and Duration of Exposure

Science.gov (United States)

Cotter, Trish; Perez, Donna; Wakefield, Melanie

2013-01-01

Objectives. We assessed the effects of levels and duration of exposure to televised antismoking advertising on cognitive and behavioral changes. Methods. We used data from a serial cross-sectional telephone survey with weekly interviews of adult smokers and recent quitters in New South Wales, Australia (n = 13 301), between April 2005 and December 2010. We merged survey data with commercial TV ratings data to estimate individuals’ exposure to antismoking advertising. Results. Logistic regression analyses indicated that after adjustment for a wide range of potential confounders, exposure to antismoking advertising at levels between 100 and 200 gross rating points per week on average over 6 to 9 weeks was associated with an increased likelihood of having (1) salient quitting thoughts and (2) recent quit attempts. Associations between exposure for shorter periods and these outcomes were not significant. Conclusions. Broadcasting schedules may affect the success of antismoking ads. Campaign planners should ensure advertising exposure at adequate frequency over relatively sustained periods to maximize impact. PMID:23763419

Televised antismoking advertising: effects of level and duration of exposure.

Science.gov (United States)

Dunlop, Sally; Cotter, Trish; Perez, Donna; Wakefield, Melanie

2013-08-01

We assessed the effects of levels and duration of exposure to televised antismoking advertising on cognitive and behavioral changes. We used data from a serial cross-sectional telephone survey with weekly interviews of adult smokers and recent quitters in New South Wales, Australia (n = 13,301), between April 2005 and December 2010. We merged survey data with commercial TV ratings data to estimate individuals' exposure to antismoking advertising. Logistic regression analyses indicated that after adjustment for a wide range of potential confounders, exposure to antismoking advertising at levels between 100 and 200 gross rating points per week on average over 6 to 9 weeks was associated with an increased likelihood of having (1) salient quitting thoughts and (2) recent quit attempts. Associations between exposure for shorter periods and these outcomes were not significant. Broadcasting schedules may affect the success of antismoking ads. Campaign planners should ensure advertising exposure at adequate frequency over relatively sustained periods to maximize impact.

A population-based case-control study of drinking-water nitrate and congenital anomalies using Geographic Information Systems (GIS) to develop individual-level exposure estimates.

Science.gov (United States)

Holtby, Caitlin E; Guernsey, Judith R; Allen, Alexander C; Vanleeuwen, John A; Allen, Victoria M; Gordon, Robert J

2014-02-05

Animal studies and epidemiological evidence suggest an association between prenatal exposure to drinking water with elevated nitrate (NO3-N) concentrations and incidence of congenital anomalies. This study used Geographic Information Systems (GIS) to derive individual-level prenatal drinking-water nitrate exposure estimates from measured nitrate concentrations from 140 temporally monitored private wells and 6 municipal water supplies. Cases of major congenital anomalies in Kings County, Nova Scotia, Canada, between 1988 and 2006 were selected from province-wide population-based perinatal surveillance databases and matched to controls from the same databases. Unconditional multivariable logistic regression was performed to test for an association between drinking-water nitrate exposure and congenital anomalies after adjusting for clinically relevant risk factors. Employing all nitrate data there was a trend toward increased risk of congenital anomalies for increased nitrate exposure levels though this was not statistically significant. After stratification of the data by conception before or after folic acid supplementation, an increased risk of congenital anomalies for nitrate exposure of 1.5-5.56 mg/L (2.44; 1.05-5.66) and a trend toward increased risk for >5.56 mg/L (2.25; 0.92-5.52) was found. Though the study is likely underpowered, these results suggest that drinking-water nitrate exposure may contribute to increased risk of congenital anomalies at levels below the current Canadian maximum allowable concentration.

Maximum surface level and temperature histories for Hanford waste tanks

International Nuclear Information System (INIS)

Flanagan, B.D.; Ha, N.D.; Huisingh, J.S.

1994-01-01

Radioactive defense waste resulting from the chemical processing of spent nuclear fuel has been accumulating at the Hanford Site since 1944. This waste is stored in underground waste-storage tanks. The Hanford Site Tank Farm Facilities Interim Safety Basis (ISB) provides a ready reference to the safety envelope for applicable tank farm facilities and installations. During preparation of the ISB, tank structural integrity concerns were identified as a key element in defining the safety envelope. These concerns, along with several deficiencies in the technical bases associated with the structural integrity issues and the corresponding operational limits/controls specified for conduct of normal tank farm operations are documented in the ISB. Consequently, a plan was initiated to upgrade the safety envelope technical bases by conducting Accelerated Safety Analyses-Phase 1 (ASA-Phase 1) sensitivity studies and additional structural evaluations. The purpose of this report is to facilitate the ASA-Phase 1 studies and future analyses of the single-shell tanks (SSTs) and double-shell tanks (DSTs) by compiling a quantitative summary of some of the past operating conditions the tanks have experienced during their existence. This report documents the available summaries of recorded maximum surface levels and maximum waste temperatures and references other sources for more specific data

Low-level exposure to organophosphate pesticides leads to restrictive lung dysfunction.

Science.gov (United States)

Peiris-John, Roshini Janet; Ruberu, Dawala Kusuma; Wickremasinghe, Ananda Rajitha; van-der-Hoek, Wim

2005-10-01

Apart from symptomology, there are very few reports on lung function following exposure to low levels of organophosphate (OP) pesticides in man. Twenty-five occupationally exposed farmers and 22 environmentally exposed freshwater fishermen were evaluated between and during OP spray seasons. Forty marine fishermen living away from agricultural areas were recruited as a control group. Forced vital capacity (FVC) and forced expiratory volume in the first second (FEV(1)) were measured by spirometry. Haemoglobin corrected erythrocyte acetylcholinesterase (AChE) levels were measured during and between (baseline estimation) spray seasons using a portable WHO-approved Test-mate system (EQM Research, Ohio). FVC ratio was lower in the farmers as compared to the controls (P<0.001) between exposure seasons. In the farmers, FVC ratio decreased further during the exposure season (P=0.023). FEV(1) was lower in the farmers as compared to the controls in both periods (P<0.05). In the fishermen, the decrease in ratios of FVC and FEV(1) following exposure to pesticides was not significant. FEV(1)/FVC ratios were similar in the three groups between (P=0.988) and during (P=0.159) exposure periods. Following exposure to OPs, AChE levels dropped 12.75% in the farmers (P<0.001) and 5.62% in the freshwater fishermen (P=0.001). Occupational exposure to OP results in restrictive lung dysfunction, a phenomenon not observed following environmental exposure.

What happens at very low levels of radiation exposure ? Are the low dose exposures beneficial ?

International Nuclear Information System (INIS)

Deniz, Dalji

2006-01-01

Full text: Radiation is naturally present in our environment and has been since the birth of this planet. The human population is constantly exposed to low levels of natural background radiation, primarily from environmental sources, and to higher levels from occupational sources, medical therapy, and other human-mediated events. Radiation is one of the best-investigated hazardous agents. The biological effects of ionizing radiation for radiation protection consideration are grouped into two categories: The deterministic and the stochastic ones. Deterministic radiation effects can be clinically diagnosed in the exposed individual and occur when above a certain t hreshold a n appropriately high dose is absorbed in the tissues and organs to cause the death of a large number of cells and consequently to impair tissue or organ functions early after exposure. A clinically observable biological effect (Acute Radiation Sendromes, ARS) occurs days to months after an acute radiation dose. Stochastic radiation effects are the chronic effects of radiation result from relatively low exposure levels delivered over long periods of time. These are sort of effects that might result from occupational exposure, or to the background exposure levels. Such late effects might be the development of malignant (cancerous) disease and of the hereditary consequences. These effects may be observed many years after the radiation exposure. There is a latent period between the initial radiation exposure and the development of the biological effect. For this reason, a stochastic effect is called a Linear or Zero-Threshold (LNT) Dose-Response Effect. There is a stochastic correlation between the number of cases of cancers or genetic defects developed inside a population and the dose received by the population at relatively large levels of radiation. These changes in gene activation seem to be able to modify the response of cells to subsequent radiation exposure, termed the a daptive response

Long-term reduction in infrared autofluorescence caused by infrared light below the maximum permissible exposure.

Science.gov (United States)

Masella, Benjamin D; Williams, David R; Fischer, William S; Rossi, Ethan A; Hunter, Jennifer J

2014-05-20

Many retinal imaging instruments use infrared wavelengths to reduce the risk of light damage. However, we have discovered that exposure to infrared illumination causes a long-lasting reduction in infrared autofluorescence (IRAF). We have characterized the dependence of this effect on radiant exposure and investigated its origin. A scanning laser ophthalmoscope was used to obtain IRAF images from two macaques before and after exposure to 790-nm light (15-450 J/cm(2)). Exposures were performed with either raster-scanning or uniform illumination. Infrared autofluorescence images also were obtained in two humans exposed to 790-nm light in a separate study. Humans were assessed with direct ophthalmoscopy, Goldmann visual fields, multifocal ERG, and photopic microperimetry to determine whether these measures revealed any effects in the exposed locations. A significant decrease in IRAF after exposure to infrared light was seen in both monkeys and humans. In monkeys, the magnitude of this reduction increased with retinal radiant exposure. Partial recovery was seen at 1 month, with full recovery within 21 months. Consistent with a photochemical origin, IRAF decreases caused by either raster-scanning or uniform illumination were not significantly different. We were unable to detect any effect of the light exposure with any measure other than IRAF imaging. We cannot exclude the possibility that changes could be detected with more sensitive tests or longer follow-up. This long-lasting effect of infrared illumination in both humans and monkeys occurs at exposure levels four to five times below current safety limits. The photochemical basis for this phenomenon remains unknown. Copyright 2014 The Association for Research in Vision and Ophthalmology, Inc.

Dose level of occupational exposure in China

International Nuclear Information System (INIS)

Tian, Y.; Zhang, L.; Ju, Y.

2008-01-01

This paper discusses the dose level of Chinese occupational exposures during 1986-2000. Data on occupational exposures from the main categories in nuclear fuel cycle (uranium enrichment and conversion, fuel fabrication, reactor operation, waste management and research activity, except for uranium mining and milling because of the lack of data), medical uses of radiation (diagnostic radiation, nuclear medicine and radiotherapy) and industrial uses of radiation (industrial radiography and radioisotope production) are presented and summarised in detail. These are the main components of occupational exposures in China. In general, the average annual effective doses show a steady decreasing trend over periods: from 2.16 to 1.16 mSv in medical uses of radiation during 1990-2000; from 1.92 to 1.18 mSv in industrial radiography during 1990-2000; from 8.79 to 2.05 mSv in radioisotope production during the period 1980-2000. Almost all the average annual effective doses in discussed occupations were lower than 5 mSv in recent years (except for well-logging: 6.86 mSv in 1999) and no monitored workers were found to have received the occupational exposure exceeding 50 mSv in a single year or 100 mSv in a five-year period. So the Chinese protection status of occupation exposure has been improved in recent years. However, the average annual effective doses in some occupations, such as diagnostic radiology and coal mining, were still much higher than that of the whole world. There are still needs for further improvement and careful monitoring of occupational exposure to protect every worker from excessive occupational exposure, especially for the workers who were neglected before. (authors)

Survey of RF exposure levels from mobile telephone base stations in Australia.

Science.gov (United States)

Henderson, S I; Bangay, M J

2006-01-01

This paper reports the results of an exposure level survey of radiofrequency electromagnetic energy originating from mobile telephone base station antennas. Measurements of CDMA800, GSM900, GSM1800, and 3G(UMTS) signals were performed at distances ranging over 50 to 500 m from 60 base stations in five Australian cities. The exposure levels from these mobile telecommunications base stations were found to be well below the general public exposure limits of the ICNIRP guidelines and the Australian radiofrequency standard (ARPANSA RPS3). The highest recorded level from a single base station was 7.8 x 10(-3) W/m(2), which translates to 0.2% of the general public exposure limit.

Derived reference levels for prenatal exposure in a radiological emergency

International Nuclear Information System (INIS)

Nuccetelli, C.; Risica, S.; Rogani, A.

2002-01-01

After the Chernobyl accident many countries renewed their radiological emergency plans, also considering the possibility of over boundary accidents. This has been set out by the 96/29/Euratom Directive (Council Directive, 1996), which states that E ach Member State shall ensure that account is taken of the fact that radiological emergencies may occur in connection with practices on or outside its territory and affect it . Moreover, after September 11, 2001, the need to prepare emergency plans for possible terroristic attacks became evident and these plans are now being worked out in many countries for intervention in case of biological, chemical and/or radiological risk. In the event of radiological emergency, all decisions to be taken are based on possible doses to critical groups (European Commission, 1997), which are the population groups most at risk. These critical groups are, in most cases, infants or children, given that dose coefficients for these age groups are generally higher than for adults. However, a new ICRP Recommendation (ICRP, 2001) has recently been published that gives dose coefficients for embryo/foetus due to intake by the mother, by inhalation or ingestion, of 31 radionuclides. Also as a result of the revaluation in the last years of the possible health effects of prenatal exposure to ionising radiation (see e.g. the review in P. Fattibene et al., 1999), the consequences for the embryo/foetus of a possible radiological emergency connected to a nuclear plant and to possible dispersion of Depleted Uranium (DU) in the environment are analysed and discussed in this paper. For the former type of accident, Derived Intervention Levels (DILs) are calculated for prenatal exposure due to acute inhalation by the mother (female member of the public) and an assessment is performed of ingestion doses for the offspring resulting from consumption of foodstuffs by the mother of which 10% of the annual consumption is contaminated at the maximum levels

Mapping of radio frequency electromagnetic field exposure levels in outdoor environment and comparing with reference levels for general public health.

Science.gov (United States)

Cansiz, Mustafa; Abbasov, Teymuraz; Kurt, M Bahattin; Celik, A Recai

2018-03-01

In this study, radio frequency electromagnetic field exposure levels were measured on the main streets in the city center of Diyarbakır, Turkey. Measured electric field levels were plotted on satellite imagery of Diyarbakır and were compared with exposure guidelines published by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). Exposure measurements were performed in dense urban, urban and suburban areas each day for 7 consecutive days. The measurement system consisted of high precision and portable spectrum analyzer, three-axis electric field antenna, connection cable and a laptop which was used to record the measurement samples as a data logger. The highest exposure levels were detected for two places, which are called Diclekent and Batıkent. It was observed that the highest instantaneous electric field strength value for Batıkent was 7.18 V/m and for Diclekent was 5.81 V/m. It was statistically determined that the main contributor band to the total exposure levels was Universal Mobile Telecommunications System band. Finally, it was concluded that all measured exposure levels were lower than the reference levels recommended by ICNIRP for general public health.

Assessment of Occupational Noise Exposure among Groundskeepers in North Carolina Public Universities

Directory of Open Access Journals (Sweden)

Jo Anne G. Balanay

2016-01-01

Full Text Available Groundskeepers may have increased risk to noise-induced hearing loss due to the performance of excessively noisy tasks. This study assessed the exposure of groundskeepers to noise in multiple universities and determined the association between noise exposure and variables (ie, university, month, tool used. Personal noise exposures were monitored during the work shift using noise dosimetry. A sound level meter was used to measure the maximum sound pressure levels from groundskeeping equipment. The mean Occupational Safety and Health Administration (OSHA and National Institute for Occupational Safety and Health (NIOSH time-weighted average (TWA noise exposures were 83.0 ± 9.6 and 88.0 ± 6.7 dBA, respectively. About 52% of the OSHA TWAs and 77% of the NIOSH TWAs exceeded 85 dBA. Riding mower use was associated with high TWA noise exposures and with having OSHA TWAs exceeding 85 and 90 dBA. The maximum sound pressure levels of equipment and tools measured ranged from 76 to 109 dBA, 82% of which were >85 dBA. These findings support that groundskeepers have excessive noise exposures, which may be effectively reduced through careful scheduling of the use of noisy equipment/tools.

Chicago transit authority train noise exposure.

Science.gov (United States)

Phan, Linh T; Jones, Rachael M

2017-06-01

To characterize noise exposure of riders on Chicago Transit Authority (CTA) trains, we measured noise levels twice on each segment of 7 of the 8 CTA train lines, which are named after colors, yielding 48 time-series measurements. We found the Blue Line has the highest noise levels compared to other train lines, with mean 76.9 dBA; and that the maximum noise level, 88.9 dBA occurred in the tunnel between the Chicago and Grand stations. Train segments involving travel through a tunnel had significantly higher noise levels than segments with travel on elevated and ground level tracks. While 8-hr doses inside the passenger cars were not estimated to exceed occupational exposure limits, train operators ride in a separate cab with operational windows and may therefore have higher noise exposures than riders. Despite the low risk of hearing loss for riders on CTA trains, in part because transit noise accounts for a small part of total daily noise exposure, 1-min average noise levels exceeded 85 dBA at times. This confirms anecdotal observations of discomfort due to noise levels, and indicates a need for noise management, particularly in tunnels.

Radiation-induced taste aversion: effects of radiation exposure level and the exposure-taste interval

International Nuclear Information System (INIS)

Spector, A.C.; Smith, J.C.; Hollander, G.R.

1986-01-01

Radiation-induced taste aversion has been suggested to possibly play a role in the dietary difficulties observed in some radiotherapy patients. In rats, these aversions can still be formed even when the radiation exposure precedes the taste experience by several hours. This study was conducted to examine whether increasing the radiation exposure level could extend the range of the exposure-taste interval that would still support the formation of a taste aversion. Separate groups of rats received either a 100 or 300 R gamma-ray exposure followed 1, 3, 6, or 24 h later by a 10-min saccharin (0.1% w/v) presentation. A control group received a sham exposure followed 1 h later by a 10-min saccharin presentation. Twenty-four hours following the saccharin presentation all rats received a series of twelve 23-h two-bottle preference tests between saccharin and water. The results indicated that the duration of the exposure-taste interval plays an increasingly more important role in determining the initial extent of the aversion as the dose decreases. The course of recovery from taste aversion seems more affected by dose than by the temporal parameters of the conditioning trial

Associations between cadmium exposure and circulating levels of sex hormones in postmenopausal women

Energy Technology Data Exchange (ETDEWEB)

Ali, Imran; Engström, Annette; Vahter, Marie [Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm (Sweden); Skerfving, Staffan; Lundh, Thomas [Division of Occupational and Environmental Medicine, University Hospital, Lund (Sweden); Lidfeldt, Jonas [Department of Community Health, Malmö University Hospital, Malmö (Sweden); Samsioe, Göran [Department of Gynecology and Obstetrics, University Hospital, Lund (Sweden); Halldin, Krister [Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm (Sweden); Åkesson, Agneta, E-mail: agneta.akesson@ki.se [Institute of Environmental Medicine, Karolinska Institutet, 171 77 Stockholm (Sweden)

2014-10-15

Recent epidemiological as well as in vivo and in vitro studies collectively suggest that the metalloestrogen cadmium (Cd) could be a potential risk factor for hormone-related cancers in particularly breast cancer. Assessment of the association between Cd exposure and levels of endogenous sex hormones is of pivotal importance, as increased levels of such have been associated with a higher risk of breast cancer in postmenopausal women. The present study investigated the perceived relationship (multivariable-adjusted linear regression analyses) between Cd exposure [blood Cd (B-Cd) and urinary Cd (U-Cd)], and serum levels of androstenedione, testosterone, estradiol, and sex-hormone binding globulin (SHBG), in 438 postmenopausal Swedish women without hormone replacement therapy (HRT). A significant positive association between B-Cd (median 3.4 nmol/L) and serum testosterone levels, as well as a significant inverse association between B-Cd and serum estradiol levels and with the estradiol/testosterone ratio were encountered. However, U-Cd (median 0.69 nmol/mmol creatinine) was inversely associated with serum estradiol levels only. Our data may suggest that Cd interferes with the levels of testosterone and estradiol in postmenopausal women, which might have implications for breast cancer risk. - Highlights: • Low level cadmium exposure may interfere with the levels of steroid hormones. • Cadmium exposure was associated with increased serum testosterone concentrations. • Cadmium exposure was associated with decreased estradiol/testosterone ratio. • Cadmium exposure may have implications for breast-cancer promotion.

Respiratory health effects of exposure to low levels of airborne endotoxin - a systematic review.

Science.gov (United States)

Farokhi, Azadèh; Heederik, Dick; Smit, Lidwien A M

2018-02-08

Elevated endotoxin levels have been measured in ambient air around livestock farms, which is a cause of concern for neighbouring residents. There is clear evidence that occupational exposure to high concentrations of airborne endotoxin causes respiratory inflammation, respiratory symptoms and lung function decline. However, health effects of exposure to low levels of endotoxin are less well described. The aim of this systematic review is to summarize published associations between exposure to relatively low levels of airborne endotoxin and respiratory health endpoints. Studies investigating respiratory effects of measured or modelled exposure to low levels of airborne endotoxin (average effects of exposure to low levels of endotoxin on respiratory symptoms and lung function. However, considerable heterogeneity existed in the outcomes of the included studies and no overall estimate could be provided by meta-analysis to quantify the possible relationship. Instead, a best evidence synthesis was performed among studies examining the exposure-response relationship between endotoxin and respiratory outcomes. Significant exposure-response relationships between endotoxin and symptoms and FEV 1 were shown in several studies, with no conflicting findings in the studies included in the best evidence synthesis. Significantly different effects of endotoxin exposure were also seen in vulnerable subgroups (atopics and patients with broncho-obstructive disease) and smokers. Respiratory health effects of exposure to low levels of airborne endotoxin (health effects, especially in vulnerable subgroups of the population.

A Population-Based Case-Control Study of Drinking-Water Nitrate and Congenital Anomalies Using Geographic Information Systems (GIS) to Develop Individual-Level Exposure Estimates

Science.gov (United States)

Holtby, Caitlin E.; Guernsey, Judith R.; Allen, Alexander C.; VanLeeuwen, John A.; Allen, Victoria M.; Gordon, Robert J.

2014-01-01

Animal studies and epidemiological evidence suggest an association between prenatal exposure to drinking water with elevated nitrate (NO3-N) concentrations and incidence of congenital anomalies. This study used Geographic Information Systems (GIS) to derive individual-level prenatal drinking-water nitrate exposure estimates from measured nitrate concentrations from 140 temporally monitored private wells and 6 municipal water supplies. Cases of major congenital anomalies in Kings County, Nova Scotia, Canada, between 1988 and 2006 were selected from province-wide population-based perinatal surveillance databases and matched to controls from the same databases. Unconditional multivariable logistic regression was performed to test for an association between drinking-water nitrate exposure and congenital anomalies after adjusting for clinically relevant risk factors. Employing all nitrate data there was a trend toward increased risk of congenital anomalies for increased nitrate exposure levels though this was not statistically significant. After stratification of the data by conception before or after folic acid supplementation, an increased risk of congenital anomalies for nitrate exposure of 1.5–5.56 mg/L (2.44; 1.05–5.66) and a trend toward increased risk for >5.56 mg/L (2.25; 0.92–5.52) was found. Though the study is likely underpowered, these results suggest that drinking-water nitrate exposure may contribute to increased risk of congenital anomalies at levels below the current Canadian maximum allowable concentration. PMID:24503976

Biomonitoring of organophosphate exposure of pesticide sprayers and comparison of exposure levels with other population groups in Thessaly (Greece).

Science.gov (United States)

Koureas, Michalis; Tsakalof, Andreas; Tzatzarakis, Manolis; Vakonaki, Elena; Tsatsakis, Aristidis; Hadjichristodoulou, Christos

2014-02-01

To evaluate the exposure of different population groups in Thessaly (Greece) to organophosphate pesticides (OPs) and investigate the dependence of exposure levels on pesticide application practices, personal protective and hygienic measures taken. For the exposure assessment, four dialkyl phosphate (DAP) metabolites of organophosphate pesticides were quantified in spot urine samples of 77 pesticide sprayers, 75 residents of the studied agricultural area non-involved in agricultural activities and 112 urban residents who served as a control group. Structured questionnaires were used to record demographic characteristics, pesticide application parameters and protective measures taken. Univariate and multivariate analysis of the obtained cross-sectional data was performed to identify potential risk factors associated with biomarker levels. It was found that total DAP median level in the sprayers' group was 24.9 μg/g creatinine (IQR: 13.0-42.1), while the rural and urban residents had significantly lower (p<0.001) levels of 11.3 μg/g creatinine (IQR: 5.3-18.7) and 11.9 μg/g creatinine (IQR: 6.3-20.3), respectively. In sprayers who had recently applied an OP pesticide (n=28), the median levels of DAP metabolites were 31.8 μg/g creatinine (IQR: 22.3-117.2). Logistic regression analysis showed that the use of full body coveralls while handling and spraying pesticides was significantly associated with lower DAP levels (OR 4.05, 95% CI 1.22 to 13.46). Also, changing clothes immediately after accidental contamination of clothing with pesticide amounts was found to be significantly associated with lower exposure levels (OR 4.04, CI 1.05 to 15.57). Our study findings confirm the increased exposure to OPs in pesticide sprayers and underline the importance of protective measures especially those that focus on dermal exposure mitigation.

Nickel exposure and plasma levels of biomarkers for assessing oxidative stress in nickel electroplating workers.

Science.gov (United States)

Tsao, Yu-Chung; Gu, Po-Wen; Liu, Su-Hsun; Tzeng, I-Shiang; Chen, Jau-Yuan; Luo, Jiin-Chyuan John

2017-07-01

The mechanism of nickel-induced pathogenesis remains elusive. To examine effects of nickel exposure on plasma oxidative and anti-oxidative biomarkers. Biomarker data were collected from 154 workers with various levels of nickel exposure and from 73 controls. Correlations between nickel exposure and oxidative and anti-oxidative biomarkers were determined using linear regression models. Workers with a exposure to high nickel levels had significantly lower levels of anti-oxidants (glutathione and catalase) than those with a lower exposure to nickel; however, only glutathione showed an independent association after multivariable adjustment. Exposure to high levels of nickel may reduce serum anti-oxidative capacity.

Modification of otoacoustic emissions following ear-level exposure to MP3 player music.

Science.gov (United States)

Bhagat, Shaum P; Davis, Anne M

2008-12-01

The purpose of this study was to examine if a pre-determined exposure level and duration of MP3 player music would result in significant changes in cochlear function when measured with audiometric and physiological methods. Distortion-product otoacoustic emissions (DPOAEs), synchronized spontaneous otoacoustic emissions (SSOAEs), and hearing thresholds were measured in 20 normal-hearing adults before and after a 30-minute MP3 player music exposure. DPOAEs were acquired with 65/45 dB SPL primary tones (f(2)=0.842-7.996 kHz) with a frequency resolution of 8 points/octave. A probe microphone system recorded ear-canal music levels and was used to equalize levels at approximately 85 dBC across individuals during the music presentation. Comparison of pre- and post-exposure measurements revealed no significant differences in hearing thresholds, but DPOAE levels in half-octave bands centered from 1.4-6.0 kHz were significantly reduced following the music exposure. Post-exposure shifts in SSOAE frequency and level were highly variable in individuals identified with SSOAEs. The results for the exposure conditions explored in this study indicate that changes in otoacoustic emissions may precede the development of music-induced hearing threshold shifts.

Exposure monitoring and risk assessment of biphenyl in the workplace.

Science.gov (United States)

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

2015-05-13

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

Exposure Monitoring and Risk Assessment of Biphenyl in the Workplace

Directory of Open Access Journals (Sweden)

Hyeon-Yeong Kim

2015-05-01

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

A hybrid modeling with data assimilation to evaluate human exposure level

Science.gov (United States)

Koo, Y. S.; Cheong, H. K.; Choi, D.; Kim, A. L.; Yun, H. Y.

2015-12-01

Exposure models are designed to better represent human contact with PM (Particulate Matter) and other air pollutants such as CO, SO2, O3, and NO2. The exposure concentrations of the air pollutants to human are determined by global and regional long range transport of global and regional scales from Europe and China as well as local emissions from urban and road vehicle sources. To assess the exposure level in detail, the multiple scale influence from background to local sources should be considered. A hybrid air quality modeling methodology combing a grid-based chemical transport model with a local plume dispersion model was used to provide spatially and temporally resolved air quality concentration for human exposure levels in Korea. In the hybrid modeling approach, concentrations from a grid-based chemical transport model and a local plume dispersion model are added to provide contributions from photochemical interactions, long-range (regional) transport and local-scale dispersion. The CAMx (Comprehensive Air quality Model with Extensions was used for the background concentrations from anthropogenic and natural emissions in East Asia including Korea while the road dispersion by vehicle emission was calculated by CALPUFF model. The total exposure level of the pollutants was finally assessed by summing the background and road contributions. In the hybrid modeling, the data assimilation method based on the optimal interpolation was applied to overcome the discrepancies between the model predicted concentrations and observations. The air quality data from the air quality monitoring stations in Korea. The spatial resolution of the hybrid model was 50m for the Seoul Metropolitan Ares. This example clearly demonstrates that the exposure level could be estimated to the fine scale for the exposure assessment by using the hybrid modeling approach with data assimilation.

Early renal effects of occupational exposure to low-level hexavalent chromium

Energy Technology Data Exchange (ETDEWEB)

Nagaya, Teruo (Dept. of Public Health, Gifu Univ. School of Medicine, Tsukasa-machi (Japan)); Ishikawa, Noriko (Occupational Hygiene Center, Gifu Labour Standards Association, Hikie (Japan)); Hata, Hideo (Occupational Hygiene Center, Gifu Labour Standards Association, Hikie (Japan)); Takahashi, Akemi (Gifu-shi Central Public Health Center, Miyako-dori (Japan)); Yoshida, Izumi (Gifu-shi Central Public Health Center, Miyako-dori (Japan)); Okamoto, Yoshinari (Gifu-shi Central Public Health Center, Miyako-dori (Japan))

1994-05-01

To detect early renal effects of occupational exposure to hexavalent chromium (Cr), urinary total proteins (U-TP), urinary albumin (U-Alb) and urinary retinol-binding protein (U-RBP) were determined in 166 male Cr platers and 106 male controls. The mean employment time in Cr plating for the platers was 12.6 years. Urinary Cr (U-Cr), which was determined as an index of Cr exposure, ranged from ''not detected'' to 19.91 [mu]g/g creatinine in the platers. The U-Cr level was lower than those in other previous studies. Age-adjusted U-TP, U-Alb or U-RBP levels were not different between the platers and the controls. In the platers, a significant positive correlation was found between age-adjusted U-TP and U-Cr, but U-Cr had no significant relation to age-adjusted U-Alb or U-RBP level. Employment time had no effect on any age-adjusted urinary proteins. The Cr exposure may have been too low to induce definite renal dysfunction. Early renal effects of low-level Cr exposure may be mild, and may not be specific to renal function. (orig.)

Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus

Energy Technology Data Exchange (ETDEWEB)

Lefevre, Sjannie, E-mail: sjannie.lefevre@biology.au.dk [Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus (Denmark); Jensen, Frank B. [Department of Biology, University of Southern Denmark, Odense (Denmark); Huong, Do.T.T. [College of Aquaculture and Fisheries, Can Tho University, Can Tho City (Viet Nam); Wang, Tobias [Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus (Denmark); Phuong, Nguyen T. [College of Aquaculture and Fisheries, Can Tho University, Can Tho City (Viet Nam); Bayley, Mark [Zoophysiology, Department of Biological Sciences, Aarhus University, Aarhus (Denmark)

2011-07-15

In this study we investigated nitrite (NO{sub 2}{sup -}) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO{sub 2max}) and critical swimming speed (U{sub crit}) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC{sub 50} of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO{sub 2max} and U{sub crit}. The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO{sub 2max} and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish.

Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus.

Science.gov (United States)

Lefevre, Sjannie; Jensen, Frank B; Huong, Do T T; Wang, Tobias; Phuong, Nguyen T; Bayley, Mark

2011-07-01

In this study we investigated nitrite (NO₂⁻) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO(2max)) and critical swimming speed (U(crit)) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC₅₀ of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO(2max) and U(crit). The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO(2max) and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish. Copyright © 2011 Elsevier B.V. All rights reserved.

Effects of nitrite exposure on functional haemoglobin levels, bimodal respiration, and swimming performance in the facultative air-breathing fish Pangasianodon hypophthalmus

International Nuclear Information System (INIS)

Lefevre, Sjannie; Jensen, Frank B.; Huong, Do.T.T.; Wang, Tobias; Phuong, Nguyen T.; Bayley, Mark

2011-01-01

In this study we investigated nitrite (NO 2 - ) effects in striped catfish, a facultative air-breather. Fish were exposed to 0, 0.4, and 0.9 mM nitrite for 0, 1, 2, 4, and 7 days, and levels of functional haemoglobin, methaemoglobin (metHb) and nitrosyl haemoglobin (HbNO) were assessed using spectral deconvolution. Plasma concentrations of nitrite, nitrate, chloride, potassium, and sodium were also measured. Partitioning of oxygen consumption was determined to reveal whether elevated metHb (causing functional hypoxia) induced air-breathing. The effects of nitrite on maximum oxygen uptake (MO 2max ) and critical swimming speed (U crit ) were also assessed. Striped catfish was highly tolerant to nitrite exposure, as reflected by a 96 h LC 50 of 1.65 mM and a moderate nitrite uptake into the blood. Plasma levels of nitrite reached a maximum after 1 day of exposure, and then decreased, never exceeding ambient levels. MetHb, HbNO and nitrate (a nitrite detoxification product) also peaked after 1 day and then decreased. Only high levels of nitrite and metHb caused reductions in MO 2max and U crit . The response of striped catfish contrasts with that seen in most other fish species and discloses efficient mechanisms of combating nitrite threats. Furthermore, even though striped catfish is an efficient air-breather, this species has the ability to sustain aerobic scope and swimming performance without air-breathing, even when faced with nitrite-induced reductions in blood oxygen carrying capacity. Our study is the first to confirm that high levels of nitrite and metHb reduce MO 2max and thereby aerobic scope, while more moderate elevations fail to do so. Further studies are needed to elucidate the mechanisms underlying the low nitrite accumulation in striped catfish.

Standing operating procedures for developing acute exposure guideline levels for hazardous chemicals

National Research Council Canada - National Science Library

National Research Council (U.S.). Subcommittee on Acute Exposure Guideline Levels

2001-01-01

... Exposure Guideline Levels for Hazardous Chemicals Subcommittee on Acute Exposure Guideline Levels Committee on Toxicology Board on Environmental Studies and Toxicology Commission on Life Sciences National Research Council NATIONAL ACADEMY PRESS Washington, D.C. i Copyrightthe cannot be not from book, paper however, version for formatting, origina...

Pesticide Exposure and Cholinesterase Levels in Migrant Farm Workers in Thailand.

Science.gov (United States)

Thetkathuek, Anamai; Yenjai, Pornthip; Jaidee, Wanlop; Jaidee, Patchana; Sriprapat, Poonsak

2017-01-01

In this study, we examined the effects of pesticides in migrant farm workers from Cambodia after workplace exposure on fruit plantations in eastern Thailand. We studied 891 migrant farm workers employed on pineapple, durian, and rambutan plantations in Thailand. Data were collected via a detailed questionnaire survey and measurements of serum cholinesterase level (SChE). The majority of subjects was male (57.7%), with an average age of 30.3 years. Most subjects (76.8%) were moderately aware of good industrial hygiene practices. SChE level was divided into four groups based on the results. Only 4.4% had normal levels of cholinesterase activity, 20.5% had slightly reduced levels, 58.5% had markedly reduced levels and were "at risk," and 16.6% who had highest levels of cholinesterase inhibition were deemed to be in an "unsafe" range. SChE was classified into two groups, SChE value of 87.5 was "normal" and 39 acres, use a backpack sprayer, or have a low level of compliance with accepted industrial hygiene practices. These three classes of workers are at increased risk of chemical exposures and developing acute or chronic illness from pesticide exposures.

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

Science.gov (United States)

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.

Environmental tobacco smoke exposure among non-smoking waiters: measurement of expired carbon monoxide levels

Directory of Open Access Journals (Sweden)

Ronaldo Laranjeira

2000-07-01

Full Text Available CONTEXT: Exposure to environmental tobacco smoke is a health risk that is of concern to patrons and of particular concern to employees of restaurants and bars. OBJECTIVE: To assess environmental tobacco smoke exposure (using expired carbon monoxide levels in non-smoking waiters before and after a normal day's shift and to compare pre-exposure levels with non-smoking medical students. DESIGN: An observational study. SETTING: Restaurants with more than 50 tables or 100 places in São Paulo. SUBJECTS: 100 non-smoking restaurant waiters and 100 non-smoking medical students in São Paulo, Brazil. MAIN MEASUREMENTS: Levels of expired carbon monoxide, measured with a Smokerlyser (Bedfont EC 50 Scientific, before and after a normal day's work. RESULTS: Waiters' pre-exposure expired carbon monoxide levels were similar to those of medical students, but after a mean of 9 hours exposure in the workplace, median levels more than doubled (2.0 ppm vs. 5.0 ppm, P <0.001. Post-exposure carbon monoxide levels were correlated with the number of tables available for smokers (Kendall's tau = 0.2, P <0.0001. CONCLUSIONS: Exposure to environmental tobacco smoke is the most likely explanation for the increase in carbon monoxide levels among these non-smoking waiters. These findings can be used to inform the ongoing public health debate on passive smoking.

Radiation exposure levels in phosphate mining activities

International Nuclear Information System (INIS)

Othman, I.; Al-Hushari, M.; Raja, G.

1992-01-01

Radon, radon daughter concentration and gamma ray exposure rate were measured at different places in the phosphate mining areas of Syria. The grab sampling method was used. For radon measurements, discrete air samples without progeny were collected over short periods of time, whereas daughters were collected on filter paper. A three-count procedure was used for the measurement of radon daughter concentrations to improve accuracy. The measurements were carried out at 37 locations selected in the mines, factories, offices and homes in the mining area. The sampling was repeated monthly for a full calendar year. Workers and their families were classified in different categories according to the nature of their jobs. The doses were estimated using proper occupancy factors. The dose equivalent from radon daughters varies from 1 mSv.y -1 to a maximum of 10 mSv.y -1 . Radon concentrations vary from 100 Bq.m -3 to several hundreds. (author)

Maximum Acceleration Recording Circuit

Science.gov (United States)

Bozeman, Richard J., Jr.

1995-01-01

Coarsely digitized maximum levels recorded in blown fuses. Circuit feeds power to accelerometer and makes nonvolatile record of maximum level to which output of accelerometer rises during measurement interval. In comparison with inertia-type single-preset-trip-point mechanical maximum-acceleration-recording devices, circuit weighs less, occupies less space, and records accelerations within narrower bands of uncertainty. In comparison with prior electronic data-acquisition systems designed for same purpose, circuit simpler, less bulky, consumes less power, costs and analysis of data recorded in magnetic or electronic memory devices. Circuit used, for example, to record accelerations to which commodities subjected during transportation on trucks.

Accommodating brightness and exposure levels in densitometry of stained polyacrylamide electrophoresis gels

International Nuclear Information System (INIS)

Tan, Han Yen; Ng, Tuck Wah; Liew, Oi Wah

2010-01-01

Flatbed scanner densitometers can be operated under various illumination and recording exposure levels. In this work, we show that optical density measurement accuracy, sensitivity, and stability of stained polyacrylamide electrophoresis gel densitometry are crucially dependent on these two factors (brightness and exposure level), notwithstanding that the source is monochromatic, spatially uniform, and the measurements are made using an accurately calibrated step wedge in tandem. We further outline a method to accommodate the intensity deviations over a range of illumination and exposure levels in order to maintain sensitivity and repeatability in the computed optical densities. Comparisons were also made with results from a commercial densitometer.

Effect of Short-term 900 MHz low level electromagnetic radiation exposure on blood serotonin and glutamate levels.

Science.gov (United States)

Eris, A H; Kiziltan, H S; Meral, I; Genc, H; Trabzon, M; Seyithanoglu, H; Yagci, B; Uysal, O

2015-01-01

Long term exposure to low level electromagnetic radiation (LLER) by using cellular phones causes serious health problems. Ten male Wistar Albino rats were anesthetized 30 min before the LLER exposure, 0.5 ml blood was taken from the tail vein of rats in order to determine control values. Rats were grouped by three and placed on a plexi-glass flat. A fixed equivalent frequency emitter device was used. A sign to be an electromagnetic field 15.14 V/m (608 mW/m(2)) in strength in the head region with 100 kHz FM modulation at 900 MHz was applied to the animals. After calculating the ideal position for the device, electromagnetic LLER energy was applied for 45 minutes from a distance to be equal with energy transmitted by a mobile phone from a 0.5-1 cm distance to their head regions. After 1.5 hours and before the rats awoke, 0.5 ml of blood was taken from the tail veins in order to determine the treatment values. Plasma 5-HT and glutamate levels were measured by enzyme immunoassay (EIA) using commercial kits. It was found that a single 45 min of LLER exposure increased the blood 5-HT level significantly, but did not change the glutamate level of rats. It was concluded that even a single 45 min of LLER exposure may produce an increase in 5-HT level without changing the blood glutamate level. Increased 5-HT level may lead to a retarded learning and a deficit in spatial memory (Tab. 2, Fig. 2, Ref. 24).

Benzene metabolite levels in blood and bone marrow of B6C3F{sub 1} mice after low-level exposure

Energy Technology Data Exchange (ETDEWEB)

Bechtold, W.E.; Strunk, M.R.; Thornton-Manning, J.R. [and others

1995-12-01

Studies at the Inhalation Toxicology Research Institute (ITRI) have explored the species-specific uptake and metabolism of benzene. Results have shown that metabolism is dependent on both dose and route of administration. Of particular interest were shifts in the major metabolic pathways as a function of exposure concentration. In these studies, B6C3F{sub 1} mice were exposed to increasing levels of benzene by either gavage or inhalation. As benzene internal dose increased, the relative amounts of muconic acid and hydroquinone decreased. In contrast, the relative amount of catechol increased with increasing exposure. These results show that the relative levels of toxic metabolites are a function of exposure level. Based on these results and assuming a linear relationship between exposure concentration and levels of bone marrow metabolites, it would be difficult to detect an elevation of any phenolic metabolites above background after occupational exposures to the OSHA Permissible Exposure Limit of 1 ppm benzene.

Risk ratios for use in establishing dose limits for occupational exposure to radiation

International Nuclear Information System (INIS)

Metcalf, P.E.; Winkler, B.C.

1980-01-01

Dose limits for occupational exposure to radiation may be established by comparing the associated mortality risk with apparently accepted levels of industrial mortality risk due to conventional hazards. Average levels of industrial mortality risk rates are frequently quoted and used in such comparisons. However, within particular occupations or industries certain groups of workers will be exposed to higher levels of risk than the average, again an apparently accepted situation. A study has been made of the ratios of maximum to average industrial mortality risk currently experienced in some South African industries. Such a ratio may be used to assess the acceptability of maximum individual-to-average exposures in particular groups of exposed individuals. (author)

Airborne exposure and soil levels associated with lead abatement of a steel tank.

Science.gov (United States)

Lange, John H

2002-02-01

This study reports on airborne exposure levels and soil concentrations of lead in regard to abatement of a steel structure (water tank). The tank was de-leaded by abrasive sand blasting. The ball of the tank had a lead surface level that exceeded the Environmental Protection Agency (EPA) definition of lead-based paint (LBP) (0.5% lead), but paint on stem and base was below this criterion. Personal and area airborne samples were collected during different activities of lead abatement of the tank. Summary results suggest during abrasive blasting of ball and stem/base personal exposure levels, as reported with arithmetic and geometric means, exceed the Occupational Safety and Health Administration (OSHA) permissible exposure limit (50 microg/m3). Highest personal exposure (occupational exposure) was associated with blasting of ball. Distribution of airborne and soil samples suggest non-normality and is best represented by a logarithmic form. Geometric standard deviations for air and soil lead support a non-normal distribution. Outlying values were found for personal and area air samples. Exposure levels associated with blasting stem/base section of tank support OSHA's policy requiring air monitoring of work at levels below the criterion established by EPA in identifying LBP. Area samples were statistically lower than personal samples associated with blasting ball and stem/base of tank. Exposure data suggest that workers performing abatement on steel structures have elevated lead exposure from surface lead. Respirator protection requirements are discussed. Soil lead concentration was suggested to decrease as distance increased from tank. Soil lead is suggested to be a result of deposition from LBP on tank surface. Minimal efforts were required to reduce average lead soil levels below EPA's upper acceptable criterion (1200 ppm Pb).

Occupational exposure levels of bioaerosol components are associated with serum levels of the acute phase protein Serum Amyloid A in greenhouse workers

DEFF Research Database (Denmark)

Madsen, Anne Mette; Thilsing, Trine; Bælum, Jesper

2016-01-01

to elevated levels of bioaerosols. The objective of this study is to assess whether greenhouse workers personal exposure to bioaerosol components was associated with serum levels of the acute phase proteins Serum Amyloid A (SAA) and C-reactive protein (CRP). METHODS: SAA and CRP levels were determined......-glucan. RESULTS: Serum levels of SAA and CRP were not significantly different in greenhouse workers and a reference group, or on the two work days. In a mixed model, SAA levels were positively associated with endotoxin exposure levels (p = 0.0007). Results for fungi were not clear. CRP levels were positively...... associated with endotoxin exposures (p = 0.022). Furthermore, when workers were categorized into three groups based on SAA and CRP serum levels endotoxin exposure was highest in the group with the highest SAA levels and in the group with middle and highest CRP levels. SAA and CRP levels were elevated...

CHURCHILL COUNTY, NEVADA ARSENIC STUDY: WATER CONSUMPTION AND EXPOSURE BIOMARKERS

Science.gov (United States)

The US Environmental Protection Agency is required to reevaluate the Maximum Contaminant Level (MCL) for arsenic in 2006. To provide data for reducing uncertainties in assessing health risks associated with exposure to low levels (<200 g/l) of arsenic, a large scale biomarker st...

Maximum power point tracking techniques for wind energy systems using three levels boost converter

Science.gov (United States)

Tran, Cuong Hung; Nollet, Frédéric; Essounbouli, Najib; Hamzaoui, Abdelaziz

2018-05-01

This paper presents modeling and simulation of three level Boost DC-DC converter in Wind Energy Conversion System (WECS). Three-level Boost converter has significant advantage compared to conventional Boost. A maximum power point tracking (MPPT) method for a variable speed wind turbine using permanent magnet synchronous generator (PMSG) is also presented. Simulation of three-level Boost converter topology with Perturb and Observe algorithm and Fuzzy Logic Control is implemented in MATLAB/SIMULINK. Results of this simulation show that the system with MPPT using fuzzy logic controller has better performance to the Perturb and Observe algorithm: fast response under changing conditions and small oscillation.

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

Science.gov (United States)

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

Investigation of the exposure level of electromagnetic fields produced by mobile telephone base stations

International Nuclear Information System (INIS)

Abukassem, I.; Kharita, M. H.

2010-12-01

The aim of this work is to investigate the real values of microwave level distribution and propagation in the locality around samples of mobile phone base station, and to compare the results with the exposure restriction limits recommenced by the International Commission on Non Ionizing Radiation Protection (ICNIRP). Measurements were performed using special meters for microwaves; the first (Narda SRM-3000) is used for electromagnetic waves frequency spectrum scanning and the second (NARDA) emr 300) determine the level of electric and magnetic fields and the power density of these waves nearby any sort of transmitters. Samples of different kinds of mobile phone base station were chosen to cover important zones of Damascus, and the region around each base station was also scanned in the emission direction and according to accessibility into the studies positions. Results showed that the signal level in all measured points is lower than the ICNIRP restriction level, but for few points the detected microwave level has relatively important values. The signal level inside building situated partially in the emission direction of the base station transmitters decreases stepwise and walls reduce considerably the signal intensity. To realize these kind of field studies in the best way and obtain the maximum profits for all people, the properties and operating system of transmitters used in mobile phone base station must be known, and therefore, it is very important to achieve a transparent collaboration between research laboratory and mobile phone company. (author)

Elevated blood lead levels from exposure via a radiator workshop.

Science.gov (United States)

Treble, R G; Thompson, T S; Morton, D N

1998-04-01

Elevated lead levels were discovered in blood samples collected from family members where both the father and the mother worked in a radiator repair workshop. The father and mother were found to have blood lead levels of 2.0 and 0.5 mumol/L (41.7 and 10.4 micrograms/dL), respectively. The father's blood lead level was just below the Canadian occupational health and safety intervention level (2.5 mumol/L or 52.1 micrograms/dL). The two children had blood lead levels of 1.0 and 0.8 mumol/L (20.8 and 16.7 micrograms/dL), both of which are in excess of the recommended guideline for intervention in the case of children (0.5 mumol/L or 10.4 micrograms/dL). The exposure of the two children was possibly due to a combination of pathways including exposure at the workshop itself during visits and also the transportation of lead-containing dust to the home environment.

Exposure to low levels of hydrogen sulfide : symptoms, sensory function, and cognitive performance

International Nuclear Information System (INIS)

Fiedler, N.; Kipen, H.; Lioy, P.; Zhang, J.; Weisel, C.

2003-01-01

Petroleum refineries, kraft paper mills, and coke ovens are some of the sources of hydrogen sulfide exposure. In 1987, the World Health Organization (WHO) recommended an ambient exposure standard of .003 ppm for odor and .01 ppm for eye irritation. In communities with high exposure levels, health effects have been documented as being headaches, eye and nasal symptoms, coughs, breathlessness and decreased psychomotor performance. Refinery workers in some jurisdictions around the world have been subjected to higher exposure levels. This report presents results of clinical studies on the neurobehavioral effects in rats. The tasks of memory and learning in rats parallels those in humans. A pilot exposure study examined the health effects of controlled exposures to 3 concentrations of hydrogen sulfide (.05, .50, and 5 ppm). It was concluded that changes in neurobehavioral measurements can be directly associated with exposure and dose-response. 25 figs

Benefits of the maximum tolerated dose (MTD) and maximum tolerated concentration (MTC) concept in aquatic toxicology

International Nuclear Information System (INIS)

Hutchinson, Thomas H.; Boegi, Christian; Winter, Matthew J.; Owens, J. Willie

2009-01-01

There is increasing recognition of the need to identify specific sublethal effects of chemicals, such as reproductive toxicity, and specific modes of actions of the chemicals, such as interference with the endocrine system. To achieve these aims requires criteria which provide a basis to interpret study findings so as to separate these specific toxicities and modes of action from not only acute lethality per se but also from severe inanition and malaise that non-specifically compromise reproductive capacity and the response of endocrine endpoints. Mammalian toxicologists have recognized that very high dose levels are sometimes required to elicit both specific adverse effects and present the potential of non-specific 'systemic toxicity'. Mammalian toxicologists have developed the concept of a maximum tolerated dose (MTD) beyond which a specific toxicity or action cannot be attributed to a test substance due to the compromised state of the organism. Ecotoxicologists are now confronted by a similar challenge and must develop an analogous concept of a MTD and the respective criteria. As examples of this conundrum, we note recent developments in efforts to validate protocols for fish reproductive toxicity and endocrine screens (e.g. some chemicals originally selected as 'negatives' elicited decreases in fecundity or changes in endpoints intended to be biomarkers for endocrine modes of action). Unless analogous criteria can be developed, the potentially confounding effects of systemic toxicity may then undermine the reliable assessment of specific reproductive effects or biomarkers such as vitellogenin or spiggin. The same issue confronts other areas of aquatic toxicology (e.g., genotoxicity) and the use of aquatic animals for preclinical assessments of drugs (e.g., use of zebrafish for drug safety assessment). We propose that there are benefits to adopting the concept of an MTD for toxicology and pharmacology studies using fish and other aquatic organisms and the

An event- and network-level analysis of college students' maximum drinking day.

Science.gov (United States)

Meisel, Matthew K; DiBello, Angelo M; Balestrieri, Sara G; Ott, Miles Q; DiGuiseppi, Graham T; Clark, Melissa A; Barnett, Nancy P

2018-04-01

Heavy episodic drinking is common among college students and remains a serious public health issue. Previous event-level research among college students has examined behaviors and individual-level characteristics that drive consumption and related consequences but often ignores the social network of people with whom these heavy drinking episodes occur. The main aim of the current study was to investigate the network of social connections between drinkers on their heaviest drinking occasions. Sociocentric network methods were used to collect information from individuals in the first-year class (N=1342) at one university. Past-month drinkers (N=972) reported on the characteristics of their heaviest drinking occasion in the past month and indicated who else among their network connections was present during this occasion. Average max drinking day indegree, or the total number of times a participant was nominated as being present on another students' heaviest drinking occasion, was 2.50 (SD=2.05). Network autocorrelation models indicated that max drinking day indegree (e.g., popularity on heaviest drinking occassions) and peers' number of drinks on their own maximum drinking occasions were significantly associated with participant maximum number of drinks, after controlling for demographic variables, pregaming, and global network indegree (e.g., popularity in the entire first-year class). Being present at other peers' heaviest drinking occasions is associated with greater drinking quantities on one's own heaviest drinking occasion. These findings suggest the potential for interventions that target peer influences within close social networks of drinkers. Copyright © 2017 Elsevier Ltd. All rights reserved.

Occupational exposure to diesel engine exhaust and serum cytokine levels.

Science.gov (United States)

Dai, Yufei; Ren, Dianzhi; Bassig, Bryan A; Vermeulen, Roel; Hu, Wei; Niu, Yong; Duan, Huawei; Ye, Meng; Meng, Tao; Xu, Jun; Bin, Ping; Shen, Meili; Yang, Jufang; Fu, Wei; Meliefste, Kees; Silverman, Debra; Rothman, Nathaniel; Lan, Qing; Zheng, Yuxin

2018-03-01

The International Agency for Research on Cancer has classified diesel engine exhaust (DEE) as a human lung carcinogen. Given that inflammation is suspected to be an important underlying mechanism of lung carcinogenesis, we evaluated the relationship between DEE exposure and the inflammatory response using data from a cross-sectional molecular epidemiology study of 41 diesel engine testing workers and 46 unexposed controls. Repeated personal exposure measurements of PM 2.5 and other DEE constituents were taken for the diesel engine testing workers before blood collection. Serum levels of six inflammatory biomarkers including interleukin (IL)-1, IL-6, IL-8, tumor necrosis factor (TNF)-α, macrophage inflammatory protein (MIP)-1β, and monocyte chemotactic protein (MCP)-1 were analyzed in all subjects. Compared to unexposed controls, concentrations of MIP-1β were significantly reduced by ∼37% in DEE exposed workers (P 397 µg/m 3 ) compared to unexposed controls. Further, significant inverse exposure-response relationships for IL-8 and MCP-1 were also found in relation to increasing PM 2.5 levels among the DEE exposed workers. Given that IL-8, MIP-1β, and MCP-1 are chemokines that play important roles in recruitment of immunocompetent cells for immune defense and tumor cell clearance, the observed lower levels of these markers with increasing PM 2.5 exposure may provide insight into the mechanism by which DEE promotes lung cancer. Environ. Mol. Mutagen. 59:144-150, 2018. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

HELLE: Health Effects of Low Level Exposures/ Gezondheidseffecten van lage blootstellingniveaus [International workshop: Influence of low level exposures to chemicals and radiation on human and ecological health

Energy Technology Data Exchange (ETDEWEB)

Schoten, Eert

1998-11-26

The Health Council is closely involved in establishing the scientific foundation of exposure limits for substances and radiation in order to protect public health. Through the years, the Council has contributed to the formulation of principles and procedures, both for carcinogenic and for noncarcinogenic agents. As a rule, the discussion with regard to the derivation of health-based recommended exposure limits centers around the appropriateness of extrapolation methods (What can be inferred from data on high exposure levels and on experimental animals?). Generally speaking, there is a lack of direct information on the health effects of low levels of exposure. Effects at these levels cannot usually be detected by means of traditional animal experiments or epidemiological research. The capacity of these analytical instruments to distinguish between ''signal'' and ''noise'' is inadequate in most cases. Annex B of this report contains a brief outline of the difficulties and the established methods for tackling this problem. In spite of this, the hope exists that the posited weak signals, if they are indeed present, can be detected by other means. The search will have to take place on a deeper level. In other words, effort must be made to discover what occurs at underlying levels of biological organization when organisms are exposed to low doses of radiation or substances. Molecular and cell biology provide various methods and techniques which give an insight into the processes within the cell. This results in an increase in the knowledge about the molecular and cellular effects of exposure to agents, or stated differently, the working mechanisms which form the basis of the health effects. Last year, the Health Council considered that the time was ripe to take stock of the state of knowledge in this field. To this end, an international working conference was held from 19 to 21 October 1997, entitled ''Health Effects of

Legal recourse for damages suffered from low-level radiation exposure

International Nuclear Information System (INIS)

Pesto-Edwards, M.M.

1984-01-01

In the past few years several events involving toxic substances have received widespread coverage by the media, thereby altering an already aware population to the hazards of exposure to toxic agents. Incidents such as Three Mile Islane, Love Canal, and Hemlock, Michigan, the exposure plight of veterans to radiation at the Nevada Test Site and to Agent Orange in Vietnam, and to the exposure of factory workers to asbestos, have been highly publicized. In part because of this publicity, the emphasis of the 1970's on controlling water and air pollution has been shifting slowly during the 1980s to the of control of hazardous waste pollution. Despite this shifting emphasis, legislative and judicial systems have been slow to respond. Few remedies are available to real and imagined victims of toxic substances. From a legal point of view, there is little difference between exposure to low levels of radiation and low levels of toxic chemicals. Both instances fall under the broader domain of environmental law. Depending on the circumstances, one instance might provide legal precedent for the other. This chapter presents examples drawn from both areas in order to illustrate current issues. The discussion is divided into four parts: (1) the common law tort theories that may be asserted when a plaintiff has suffered injury resulting from exposure to low-level radiation or other toxic substances; (2) the difficulties posed by the relief mechanisms rooted in traditional common law; (3) current federal legislation, along with its merits and shortcomings; and (4) solutions to the obstacles now faced by plaintiffs in attempting to recover their damages. Also discussed are suggested judicial and legislative solutions designed to remedy the damages caused to persons exposed to toxic wastes

Glutathione level after long-term occupational elemental mercury exposure

International Nuclear Information System (INIS)

Kobal, Alfred Bogomir; Prezelj, Marija; Horvat, Milena; Krsnik, Mladen; Gibicar, Darija; Osredkar, Josko

2008-01-01

Many in vitro and in vivo studies have elucidated the interaction of inorganic mercury (Hg) and glutathione. However, human studies are limited. In this study, we investigated the potential effects of remote long-term intermittent occupational elemental Hg vapour (Hg o ) exposure on erythrocyte glutathione levels and some antioxidative enzyme activities in ex-mercury miners in the period after exposure. The study included 49 ex-mercury miners divided into subgroups of 28 still active, Hg o -not-exposed miners and 21 elderly retired miners, and 41 controls, age-matched to the miners subgroup. The control workers were taken from 'mercury-free works'. Reduced glutathione (GSH) and oxidized disulphide glutathione (GSSG) concentrations in haemolysed erythrocytes were determined by capillary electrophoresis, while total glutathione (total GSH) and the GSH/GSSG ratio were calculated from the determined values. Catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR) activities in erythrocytes were measured using commercially available reagent kits, while urine Hg (U-Hg) concentrations were determined by cold vapour atomic absorption (CVAAS). No correlation of present U-Hg levels, GSH, GSSG, and antioxidative enzymes with remote occupational biological exposure indices were found. The mean CAT activity in miners and retired miners was significantly higher (p o could be an inductive and additive response to maintain the balance between GSH and antioxidative enzymes in interaction with the Hg body burden accumulated during remote occupational exposure, which does not represent a severely increased oxidative stress

Low-exposure tritium radiotoxicity in mammals

International Nuclear Information System (INIS)

Dobson, R.L.

1982-01-01

A special feature of tritium radiation is the very low energy of the beta particles (5.7 keV average, 18 keV maximum). This low energy results in very short particle ranges in tissue, ranges that are less than cell dimensions. Another result of the low energy is that the ionization density along beta-ray tracks (even though the tracks are short) is significantly greater than that associated with secondary electrons from gamma rays. The studies of tritium radiotoxicity reviewed, involving chronic 3 HOH exposures in mammals, demonstrate in both mice and monkeys that biological effects can be measured following remarkably low levels of exposure --- levels in the range of serious practical interest to radiation protection. (Namekawa, K.)

Consumer product exposures associated with urinary phthalate levels in pregnant women

Science.gov (United States)

Buckley, Jessie P.; Palmieri, Rachel T.; Matuszewski, Jeanine M.; Herring, Amy H.; Baird, Donna D.; Hartmann, Katherine E.; Hoppin, Jane A.

2012-01-01

Human phthalate exposure is ubiquitous, but little is known regarding predictors of urinary phthalate levels. To explore this, 50 pregnant women aged 18–38 years completed two questionnaires on potential phthalate exposures and provided a first morning void. Urine samples were analyzed for 12 phthalate metabolites. Associations with questionnaire items were evaluated via Wilcoxon tests and t-tests, and r-squared values were calculated in multiple linear regression models. Few measured factors were statistically significantly associated with phthalate levels. Individuals who used nail polish had higher levels of mono-butyl phthalate (p=0.048) than non-users. Mono-benzyl phthalate levels were higher among women who used eye makeup (p=0.034) or used makeup on a regular basis (p=0.004). Women who used cologne or perfume had higher levels of di-(2-ethylhexyl) phthalate metabolites. Household products, home flooring or paneling, and other personal care products were also associated with urinary phthalates. The proportion of variance in metabolite concentrations explained by questionnaire items ranged between 0.31 for mono-ethyl phthalate and 0.42 for mono-n-methyl phthalate. Although personal care product use may be an important predictor of urinary phthalate levels, most of the variability in phthalate exposure was not captured by our relatively comprehensive set of questionnaire items. PMID:22760436

Maximum permissible body burdens and maximum permissible concentrations of radionuclides in air and in water for occupational exposure. Recommendations of the National Committee on Radiation Protection. Handbook 69

Energy Technology Data Exchange (ETDEWEB)

NONE

1959-06-05

The present Handbook and its predecessors stem from the Second International Congress of Radiology, held in Stockholm in 1928. At that time, under the auspices of the Congress, the International Commission on Radiological Protection (ICRP) was organized to deal initially with problems of X-ray protection and later with radioactivity protection. At that time 'permissible' doses of X-rays were estimated primarily in terms of exposures which produced erythema, the amount of exposure which would produce a defined reddening of the skin. Obviously a critical problem in establishing criteria for radiation protection was one of developing useful standards and techniques of physical measurement. For this reason two of the organizations in this country with a major concern for X-ray protection, the American Roentgen Ray Society and the Radiology Society of North America, suggested that the National Bureau of Standards assume responsibility for organizing representative experts to deal with the problem. Accordingly, early in 1929, an Advisory Committee on X-ray and Radium Protection was organized to develop recommendations on the protection problem within the United States and to formulate United States points of view for presentation to the International Commission on Radiological Protection. The organization of the U.S. Advisory Committee included experts from both the medical and physical science fields. The recommendations of this Handbook take into consideration the NCRP statement entitled 'Maximum Permissible Radiation Exposures to Man', published as an addendum to Handbook 59 on April 15, 1958. As noted above this study was carried out jointly by the ICRP and the NCRP, and the complete report is more extensive than the material contained in this Handbook.

Maximum permissible body burdens and maximum permissible concentrations of radionuclides in air and in water for occupational exposure. Recommendations of the National Committee on Radiation Protection. Handbook 69

International Nuclear Information System (INIS)

1959-01-01

The present Handbook and its predecessors stem from the Second International Congress of Radiology, held in Stockholm in 1928. At that time, under the auspices of the Congress, the International Commission on Radiological Protection (ICRP) was organized to deal initially with problems of X-ray protection and later with radioactivity protection. At that time 'permissible' doses of X-rays were estimated primarily in terms of exposures which produced erythema, the amount of exposure which would produce a defined reddening of the skin. Obviously a critical problem in establishing criteria for radiation protection was one of developing useful standards and techniques of physical measurement. For this reason two of the organizations in this country with a major concern for X-ray protection, the American Roentgen Ray Society and the Radiology Society of North America, suggested that the National Bureau of Standards assume responsibility for organizing representative experts to deal with the problem. Accordingly, early in 1929, an Advisory Committee on X-ray and Radium Protection was organized to develop recommendations on the protection problem within the United States and to formulate United States points of view for presentation to the International Commission on Radiological Protection. The organization of the U.S. Advisory Committee included experts from both the medical and physical science fields. The recommendations of this Handbook take into consideration the NCRP statement entitled 'Maximum Permissible Radiation Exposures to Man', published as an addendum to Handbook 59 on April 15, 1958. As noted above this study was carried out jointly by the ICRP and the NCRP, and the complete report is more extensive than the material contained in this Handbook

Application of physiologically based pharmacokinetic modeling in setting acute exposure guideline levels for methylene chloride.

NARCIS (Netherlands)

Bos, Peter Martinus Jozef; Zeilmaker, Marco Jacob; Eijkeren, Jan Cornelis Henri van

2006-01-01

Acute exposure guideline levels (AEGLs) are derived to protect the human population from adverse health effects in case of single exposure due to an accidental release of chemicals into the atmosphere. AEGLs are set at three different levels of increasing toxicity for exposure durations ranging from

The Impact of Different Permissible Exposure Limits on Hearing Threshold Levels Beyond 25 dBA.

Science.gov (United States)

Sayapathi, Balachandar S; Su, Anselm Ting; Koh, David

2014-10-01

Development of noise-induced hearing loss is reliant on a few factors such as frequency, intensity, and duration of noise exposure. The occurrence of this occupational malady has doubled from 120 million to 250 million in a decade. Countries such as Malaysia, India, and the US have adopted 90 dBA as the permissible exposure limit. According to the US Occupational Safety and Health Administration (OSHA), the exposure limit for noise is 90 dBA, while that of the US National Institute of Occupational Safety and Health (NIOSH) is 85 dBA for 8 hours of noise exposure. This study aimed to assess the development of hearing threshold levels beyond 25 dBA on adoption of 85 dBA as the permissible exposure limit compared to 90 dBA. This is an intervention study done on two automobile factories. There were 203 employees exposed to noise levels beyond the action level. Hearing protection devices were distributed to reduce noise levels to a level between the permissible exposure limit and action level. The permissible exposure limits were 90 and 85 dBA in factories 1 and 2, respectively, while the action levels were 85 and 80 dBA, respectively. The hearing threshold levels of participants were measured at baseline and at first month of postshift exposure of noise. The outcome was measured by a manual audiometer. McNemar and chi-square tests were used in the statistical analysis. We found that hearing threshold levels of more than 25 dBA has changed significantly from pre-intervention to post-intervention among participants from both factories (3000 Hz for the right ear and 2000 Hz for the left ear). There was a statistically significant association between participants at 3000 Hz on the right ear at 'deteriorated' level ( χ² (1) = 4.08, φ = - 0.142, P = 0.043), whereas there was worsening of hearing threshold beyond 25 dBA among those embraced 90 dBA. The adoption of 85 dBA as the permissible exposure limit has preserved hearing threshold level among participants at 3000 Hz

A novel approach to estimating potential maximum heavy metal exposure to ship recycling yard workers in Alang, India

International Nuclear Information System (INIS)

Deshpande, Paritosh C.; Tilwankar, Atit K.; Asolekar, Shyam R.

2012-01-01

The 180 ship recycling yards located on Alang–Sosiya beach in the State of Gujarat on the west coast of India is the world's largest cluster engaged in dismantling. Yearly 350 ships have been dismantled (avg. 10,000 ton steel/ship) with the involvement of about 60,000 workers. Cutting and scrapping of plates or scraping of painted metal surfaces happens to be the commonly performed operation during ship breaking. The pollutants released from a typical plate-cutting operation can potentially either affect workers directly by contaminating the breathing zone (air pollution) or can potentially add pollution load into the intertidal zone and contaminate sediments when pollutants get emitted in the secondary working zone and gets subjected to tidal forces. There was a two-pronged purpose behind the mathematical modeling exercise performed in this study. First, to estimate the zone of influence up to which the effect of plume would extend. Second, to estimate the cumulative maximum concentration of heavy metals that can potentially occur in ambient atmosphere of a given yard. The cumulative maximum heavy metal concentration was predicted by the model to be between 113 μg/Nm 3 and 428 μg/Nm 3 (at 4 m/s and 1 m/s near-ground wind speeds, respectively). For example, centerline concentrations of lead (Pb) in the yard could be placed between 8 and 30 μg/Nm 3 . These estimates are much higher than the Indian National Ambient Air Quality Standards (NAAQS) for Pb (0.5 μg/Nm 3 ). This research has already become the critical science and technology inputs for formulation of policies for eco-friendly dismantling of ships, formulation of ideal procedure and corresponding health, safety, and environment provisions. The insights obtained from this research are also being used in developing appropriate technologies for minimizing exposure to workers and minimizing possibilities of causing heavy metal pollution in the intertidal zone of ship recycling yards in India. -- Highlights

Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making.

Science.gov (United States)

Rodeheffer, Christopher D; Chabal, Sarah; Clarke, John M; Fothergill, David M

2018-06-01

Submarines routinely operate with higher levels of ambient carbon dioxide (CO2) (i.e., 2000 - 5000 ppm) than what is typically considered normal (i.e., 400 - 600 ppm). Although significant cognitive impairments are rarely reported at these elevated CO2 levels, recent studies using the Strategic Management Simulation (SMS) test have found impairments in decision-making performance during acute CO2 exposure at levels as low as 1000 ppm. This is a potential concern for submarine operations, as personnel regularly make mission-critical decisions that affect the safety and efficiency of the vessel and its crew while exposed to similar levels of CO2. The objective of this study was to determine if submariner decision-making performance is impacted by acute exposure to levels of CO2 routinely present in the submarine atmosphere during sea patrols. Using a subject-blinded balanced design, 36 submarine-qualified sailors were randomly assigned to receive 1 of 3 CO2 exposure conditions (600, 2500, or 15,000 ppm). After a 45-min atmospheric acclimation period, participants completed an 80-min computer-administered SMS test as a measure of decision making. There were no significant differences for any of the nine SMS measures of decision making between the CO2 exposure conditions. In contrast to recent research demonstrating cognitive deficits on the SMS test in students and professional-grade office workers, we were unable to replicate this effect in a submariner population-even with acute CO2 exposures more than an order of magnitude greater than those used in previous studies that demonstrated such effects.Rodeheffer CD, Chabal S, Clarke JM, Fothergill DM. Acute exposure to low-to-moderate carbon dioxide levels and submariner decision making. Aerosp Med Hum Perform. 2018; 89(6):520-525.

Background radiation levels and medical exposure levels in Australia

International Nuclear Information System (INIS)

Webb, D.V.; Solomon, S.B.; Thomson, J.E.M.

1999-01-01

The average effective background dose received by the Australian population has been reassessed to be ∼1.5 millisievert (mSv) per year. Over half of this exposure arises from exposure from terrestrial radiation and cosmic rays, the remainder from radionuclides within the body and from inhalation of radon progeny. This background is to be compared with medical radiation, primarily diagnostic, which could add half as much again to the population exposure. This paper reviews research programmes carried out by the Australian Radiation Laboratory to study radiation exposure from natural background and from medical use. While the latter exposure is accepted to have a social benefit, there is a need to ensure that doses are no more than necessary to provide effective diagnosis and optimal treatment. Copyright (1999) Australasian Radiation Protection Society Inc

Methylene chloride exposure and carboxyhemoglobin levels in cabinetmakers

Science.gov (United States)

Banjoko, Sunny O.; Sridhar Mynapelli, K. C.; Ogunkola, Isiah O.; Masheyi, Olatunde O.

2007-01-01

Methylene chloride (MeCl2) is a clear colorless volatile sweet smelling lipophilic solvent used as a constituent of wood vanishes and paints. Human exposure is mainly due to inhalation and its biotransformation by the hepatic mixed function oxidases (MFO) leads to formation of carbon monoxide (CO). Simultaneous exposure to MeCl2 and increased ambient CO results in undesirably increased carboxyhemoglobin (COHb) formation, which predisposes to carboxyhemoglobinaemia with the central nervous system as the primary target organ of toxicity. In this study, ambient CO levels were determined using a CO personal monitor in different pasts of Ibadan Nigeria and work place microenvironment of 50 Cabinet makers (test group) and 50 volunteer (control) in non-furniture making occupations. Mann Whitney U and Kruskaal Wallis were the statistical methods of analysis used. Questionnaires were administered to both groups carboxyhaemoglobin levels were determined in venous blood drawn from individuals in the two groups by differential spectrophotometric method. Ambient CO levels in Ibadan were observed to be between 4 and 52 ppm with a mean of 20 ppm. Work environment CO levels were significantly higher in test subjects than controls at 5.2 ± 1.08 ppm and 2.08 ± 0.91 ppm respectively (P 0.05). It is therefore imperative to substitute MeCl2 for safer chemicals in wood vanish and paints and the use of protective gas masks and adequate ventilation should be mandatory whenever MeCl2 is used. PMID:21938216

Long-term exposure to low-level arsenic in drinking water and diabetes incidence

DEFF Research Database (Denmark)

Bräuner, Elvira Vaclavik; Nordsborg, Rikke Baastrup; Andersen, Zorana Jovanovic

2014-01-01

BACKGROUND: Established causes of diabetes do not fully explain the present epidemic. High-level arsenic exposure has been implicated in diabetes risk, but the effect of low-level arsenic exposure in drinking water remains unclear. OBJECTIVE: We sought to determine whether long-term exposure to low......-level arsenic in drinking water in Denmark is associated with an increased risk of diabetes using a large prospective cohort. METHODS: During 1993-1997, we recruited 57,053 persons. We followed each cohort member for diabetes occurrence from enrollment until 31 December 2006. We traced and geocoded residential...... exposure and diabetes incidence, separately for two definitions of diabetes: all cases and a more strict definition in which cases of diabetes based solely on blood glucose results were excluded. RESULTS: Over a mean follow-up period of 9.7 years for 52,931 eligible participants, there were a total of 4...

Lawrence Livermore National Laboratory low-level waste systems performance assessment

International Nuclear Information System (INIS)

1990-11-01

This Low-Level Radioactive Waste (LLW) Systems Performance Assessment (PA) presents a systematic analysis of the potential risks posed by the Lawrence Livermore National Laboratory (LLNL) waste management system. Potential risks to the public and environment are compared to established performance objectives as required by DOE Order 5820.2A. The report determines the associated maximum individual committed effective dose equivalent (CEDE) to a member of the public from LLW and mixed waste. A maximum annual CEDE of 0.01 mrem could result from routine radioactive liquid effluents. A maximum annual CEDE of 0.003 mrem could result from routine radioactive gaseous effluents. No other pathways for radiation exposure of the public indicated detectable levels of exposure. The dose rate, monitoring, and waste acceptance performance objectives were found to be adequately addressed by the LLNL Program. 88 refs., 3 figs., 17 tabs

Exposure of the orthopaedic surgeon to radiation

Energy Technology Data Exchange (ETDEWEB)

Katoh, Kiyonobu; Koga, Takamasa; Matsuzaki, Akio; Kido, Masaki; Satoh, Tetsunori [Fukuoka Univ. (Japan). Chikushi Hospital

1995-09-01

We monitored the amount of radiation received by surgeons and assistants during surgery carried out with fluoroscopic assistance. The radiation was monitored with the use of MYDOSE MINIX PDM107 made by Aloka Co. Over a one year period from Aug 20, 1992 to Aug 19, 1993, a study was undertaken to evaluate exposure of the groin level to radiation with or without use of the lead apron during 106 operation (Group-1). In another group, radiation was monitored at the breast and groin level outside of the lead apron during 39 operations (Group-2). In Group-1, the average exposure per person during one year was 46.0 {mu}SV and the average exposure for each procedure was 1.68 {mu}SV. The use of the lead apron affirmed its protective value; the average radiation dose at the groin level out-side of the apron was 9.11 {mu}SV, the measured dose beneath the apron 0.61 {mu}SV. The average dose of exposure to the head, breast at groin level outside of the lead apron, were 7.68 {mu}SV, 16.24 {mu}SV, 32.04 {mu}SV respectively. This study and review of the literature indicate that the total amount of radiation exposure during surgery done with fluoroscopic control remains well within maximum exposure limits. (author).

Exposure of the orthopaedic surgeon to radiation

International Nuclear Information System (INIS)

Katoh, Kiyonobu; Koga, Takamasa; Matsuzaki, Akio; Kido, Masaki; Satoh, Tetsunori

1995-01-01

We monitored the amount of radiation received by surgeons and assistants during surgery carried out with fluoroscopic assistance. The radiation was monitored with the use of MYDOSE MINIX PDM107 made by Aloka Co. Over a one year period from Aug 20, 1992 to Aug 19, 1993, a study was undertaken to evaluate exposure of the groin level to radiation with or without use of the lead apron during 106 operation (Group-1). In another group, radiation was monitored at the breast and groin level outside of the lead apron during 39 operations (Group-2). In Group-1, the average exposure per person during one year was 46.0 μSV and the average exposure for each procedure was 1.68 μSV. The use of the lead apron affirmed its protective value; the average radiation dose at the groin level out-side of the apron was 9.11 μSV, the measured dose beneath the apron 0.61 μSV. The average dose of exposure to the head, breast at groin level outside of the lead apron, were 7.68 μSV, 16.24 μSV, 32.04 μSV respectively. This study and review of the literature indicate that the total amount of radiation exposure during surgery done with fluoroscopic control remains well within maximum exposure limits. (author)

A Method to Estimate Students’ Exposure to Road Traffic Noise Events

Directory of Open Access Journals (Sweden)

Simone Secchi

2018-03-01

Full Text Available The correlation between exposure to traffic noise and students’ performance and annoyance has been investigated in literature mainly considering the relationship between indoor equivalent A-weighted sound pressure level (LAeq and students’ cognitive impairment. Annoyance is frequently related to the effect of short-duration noise events characterized by high sound pressure levels, such as those due to aircraft fly-over and pass-by of buses, heavy trucks, motorcycles, or street sweepers. These noise events are often described, over specific measurement periods, in terms of maximum A-weighted sound pressure level, LAmax, or statistical levels, such as LA1 or LA10. This aspect is not considered in the noise maps drawn in accordance with the European Environmental Noise Directive, as they provide the LAeq only, determined over day, evening, and night periods. In this paper, students’ exposure to road traffic noise is analyzed by means of regression equations obtained by the authors between LAeq and A-weighted maximum and statistical levels due to road traffic noise. The traffic noise of 28 urban streets was monitored during the opening period of Italian schools. A method is described to estimate students’ exposure to noise from data made available on noise maps by the municipalities of metropolitan areas. The application of this method to the case study of Florence shows that almost 60% of students from municipal primary and lower secondary schools could be exposed to the maximum sound pressure level (SPL inside the classroom greater than 55 dB(A every hour, probably exceeding the typical background noise in classrooms by more than 10 dB.

[Myocardial ultrastructural changes in rats following different levels of acute +Gz exposure].

Science.gov (United States)

Zheng, Jun; Liu, Cheng-gang; Ren, Li; Xiao, Xiao-guang; Xu, Shu-xuan; Wang, Ping; Ji, Gui-ying

2004-06-01

To observe the effects of different levels of acute +Gz exposure on myocardial ultrastructure of rats and provide experimental basis for further development of anti-G measures. Twenty male Wistar rats were randomly divided into 4 groups (n=5): normal control group, +20 Gz group, +10 Gz group and +5 Gz group. Profile of the centrifuge +Gz exposure was trapezoidal, in which +20 Gz lasted for 30 s, +10 Gz for 1.5 min. +5 Gz exposure was repeated for 3 times with 30 min interval and each for 1.5 min. Myocardial tissue of left ventricle was sampled for transmission electron microscopy 5 h after exposure. +20 Gz and +10 Gz exposure caused obvious edema of myocardial and endothelial cells, myofibril disorder and injuries of mitochondria and nucleus. Breaks of myocardial fiber, formation of contraction bands and rupture of mitochondria were also observed in +20 Gz group. In +5 Gz group, there was still slight edema of myocardial and endothelial cells, while organic changes of myocardial ultrastructure were not observed. High +Gz exposure can cause myocardial ultrastructural injury in rats. Slight reversible injured response can also be observed in myocardial cell after repeated moderate level of +Gz exposure. This indicates that attention should be paid to the study of the effect of high +Gz on heart in pilots.

A Model to Determine the Level of Serum Aldosterone in the Workers Attributed to the Combined Effects of Sound Pressure Level, Exposure Time and Serum Potassium Level: A Field-Based Study

Directory of Open Access Journals (Sweden)

Parvin Nassiri

2016-09-01

Full Text Available Background Occupational exposure to excessive noise is one of the biggest work-related challenges in the world. This phenomenon causes the release of stress-related hormones, which in turn, negatively affects cardiovascular risk factors. Objectives The current study study aimed to determine the level of workers’ serum aldosterone in light of the combined effect of sound pressure level, exposure time and serum potassium level. Methods This cross-sectional, descriptive, analytical study was conducted on 45 workers of Gol-Gohar Mining and Industrial Company in the fall of 2014. The subjects were divided into three groups (one control and two case groups, each including 15 workers. Participants in the control group were selected from workers with administrative jobs (exposure to the background noise. On the other hand, participants in the case groups were selected from the concentrator and pelletizing factories exposed to excessive noise. Serum aldosterone and potassium levels of participants were assessed at three different time intervals: at the beginning of the shift and before exposure to noise (7:30 - 8:00 AM, during exposure to noise (10:00 - 10:30 AM, and during continuous exposure (1:30 - 2:00 PM. The obtained data were transferred into SPSS ver. 18. Repeated measures analysis of variance (ANOVA was used to develop the statistical model of workers’ aldosterone level in light of the combined effect of sound pressure level, exposure time, and serum potassium level. Results The results of the final statistical model to determine the level of serum aldosterone based on the combined effect of sound pressure level, exposure time and serum potassium level indicated that the sound pressure level had a significant influence on the human’s serum aldosterone level (P = 0.04. In addition, the effects of exposure time and serum potassium on aldosterone level were statistically significant with P-values of 0.008 and 0.001, respectively. Conclusions

Multi-level restricted maximum likelihood covariance estimation and kriging for large non-gridded spatial datasets

KAUST Repository

Castrillon, Julio

2015-11-10

We develop a multi-level restricted Gaussian maximum likelihood method for estimating the covariance function parameters and computing the best unbiased predictor. Our approach produces a new set of multi-level contrasts where the deterministic parameters of the model are filtered out thus enabling the estimation of the covariance parameters to be decoupled from the deterministic component. Moreover, the multi-level covariance matrix of the contrasts exhibit fast decay that is dependent on the smoothness of the covariance function. Due to the fast decay of the multi-level covariance matrix coefficients only a small set is computed with a level dependent criterion. We demonstrate our approach on problems of up to 512,000 observations with a Matérn covariance function and highly irregular placements of the observations. In addition, these problems are numerically unstable and hard to solve with traditional methods.

Is ultraviolet radiation a synergistic stressor in combined exposures? The case study of Daphnia magna exposure to UV and carbendazim

International Nuclear Information System (INIS)

Ribeiro, Fabianne; Ferreira, Nuno C.G.; Ferreira, Abel; Soares, Amadeu M.V.M.; Loureiro, Susana

2011-01-01

The toxicological assessment of chemical compounds released to the environment is more accurate when mixtures of chemicals and/or interactions between chemicals and natural stressors are considered. Ultraviolet radiation can be taken as a natural stressor since the levels of UV are increasing due to the decrease of its natural filter, the stratospheric ozone concentration. Therefore, a combination of chemical exposures and increasing UV irradiance in aquatic environments is likely to occur. In the current study, combined effects of carbendazim and ultraviolet radiation were evaluated, using selected life traits as endpoints on Daphnia magna. To design combined exposures, first single chemical and natural stressor bioassays were performed: a reproduction test with carbendazim and a reproduction, feeding inhibition and Energy budget test with ultraviolet radiation. Following single exposures, the combinations of stressors included exposures to UV radiation and carbendazim for a maximum exposure time of 4 h, followed by a post-exposure period in chemically contaminated medium for a maximum of 15 days, depending on the endpoint, where the effects of the combined exposures were investigated. Statistical analyses of the data set were performed using the MixTox tool and were based on the conceptual model of Independent Action (IA) and possible deviations to synergism or antagonism, dose-ratio or dose-level response pattern. Both ultraviolet radiation and carbendazim as single stressors had negative impacts on the measured life traits of daphnids, a decrease on both feeding rates and reproduction was observed. Feeding rates and reproduction of D. magna submitted to combined exposures of ultraviolet radiation and carbendazim showed a dose-ratio deviation from the conceptual model as the best description of the data set, for both endpoints. For feeding inhibition, antagonism was observed when the UV radiation was the dominant item in combination, and for reproduction

Assessing multimedia/multipathway exposures to inorganic arsenic at population and individual level using MERLIN-Expo.

Science.gov (United States)

Van Holderbeke, Mirja; Fierens, Tine; Standaert, Arnout; Cornelis, Christa; Brochot, Céline; Ciffroy, Philippe; Johansson, Erik; Bierkens, Johan

2016-10-15

In this study, we report on model simulations performed using the newly developed exposure tool, MERLIN-Expo, in order to assess inorganic arsenic (iAs) exposure to adults resulting from past emissions by non-ferrous smelters in Belgium (Northern Campine area). Exposure scenarios were constructed to estimate external iAs exposure as well as the toxicologically relevant As (tAs, i.e., iAs, MMA and DMA) body burden in adults living in the vicinity of the former industrial sites as compared to adults living in adjacent areas and a reference area. Two scenarios are discussed: a first scenario studying exposure to iAs at the aggregated population level and a second scenario studying exposure at the individual level for a random sub-sample of subjects in each of the three different study areas. These two scenarios only differ in the type of human related input data (i.e., time-activity data, ingestion rates and consumption patterns) that were used, namely averages (incl. probability density functions, PDFs) in the simulation at population level and subject-specific values in the simulation at individual level. The model predictions are shown to be lower than the corresponding biomonitoring data from the monitoring campaign. Urinary tAs levels in adults, irrespective of the area they lived in, were under-predicted by MERLIN-Expo by 40% on average. The model predictions for individual adults, by contrast, under-predict the biomonitoring data by 7% on average, but with more important under-predictions for subjects at the upper end of exposure. Still, average predicted urinary tAs levels from the simulations at population level and at individual level overlap, and, at least for the current case, lead to similar conclusions. These results constitute a first and partial verification of the model performance of MERLIN-Expo when dealing with iAs in a complex site-specific exposure scenario, and demonstrate the robustness of the modelling tool for these situations. Copyright �

Low-level exposure of guinea pigs and marmosets to sarin vapour in air: Lowest-observable-adverse-effect level (LOAEL) for miosis

NARCIS (Netherlands)

Helden, H.P.M. van; Trap, H.C.; Kuijpers, W.C.; Oostdijk, J.P.; Benschop, H.P.; Langenberg, J.P.

2004-01-01

The purpose of this pilot study was to indicate, for low-level exposure of conscious guinea pigs and marmoset monkeys to sarin vapour in air, the lowest-observable-adverse-effect level (LOAEL) of sarin for miosis. This is the concentration × time (C·t) value (t = 5 h) of exposure at which miosis

SAR exposure from UHF RFID reader in adult, child, pregnant woman, and fetus anatomical models.

Science.gov (United States)

Fiocchi, Serena; Markakis, Ioannis A; Ravazzani, Paolo; Samaras, Theodoros

2013-09-01

The spread of radio frequency identification (RFID) devices in ubiquitous applications without their simultaneous exposure assessment could give rise to public concerns about their potential adverse health effects. Among the various RFID system categories, the ultra high frequency (UHF) RFID systems have recently started to be widely used in many applications. This study addresses a computational exposure assessment of the electromagnetic radiation generated by a realistic UHF RFID reader, quantifying the exposure levels in different exposure scenarios and subjects (two adults, four children, and two anatomical models of women 7 and 9 months pregnant). The results of the computations are presented in terms of the whole-body and peak spatial specific absorption rate (SAR) averaged over 10 g of tissue to allow comparison with the basic restrictions of the exposure guidelines. The SAR levels in the adults and children were below 0.02 and 0.8 W/kg in whole-body SAR and maximum peak SAR levels, respectively, for all tested positions of the antenna. On the contrary, exposure of pregnant women and fetuses resulted in maximum peak SAR(10 g) values close to the values suggested by the guidelines (2 W/kg) in some of the exposure scenarios with the antenna positioned in front of the abdomen and with a 100% duty cycle and 1 W radiated power. Copyright © 2013 Wiley Periodicals, Inc.

Inhalation exposure and health risk levels to BTEX and carbonyl compounds of traffic policeman working in the inner city of Bangkok, Thailand

Science.gov (United States)

Kanjanasiranont, Navaporn; Prueksasit, Tassanee; Morknoy, Daisy

2017-03-01

Benzene, toluene, ethylbenzene and xylenes (BTEX) and carbonyl compounds (CCs) are recognized traffic-related air pollutants in urban environments and are the focus of this study. In Bangkok, the BTEX and CC concentrations in both ambient air and personal exposure samples were studied during two periods (April-May and August-September 2014) at four different sampling sites around the Pathumwan District (three intersections and one T-junction). Traffic policemen, representing the high-exposure group for these toxic air pollutants, were observed, and the health risk to these workers was evaluated. Toluene was the predominant aromatic compound in the ambient and personal exposure samples. The maximum average ambient concentration of BTEX was 2968.96 μg/m3. Formaldehyde and acetaldehyde were the most abundant CCs at all of the sampling sites, with the greatest mean concentrations of these substances being 21.50 μg/m3 and 64.82 μg/m3, respectively. In the personal exposure samples, the highest levels of BTEX, formaldehyde and acetaldehyde concentrations were 2231.85 μg/m3, 10.61 μg/m3, and 16.03 μg/m3, respectively. In terms of risk assessment, benzene posed the greatest cancer risk (at the 95% CI), followed by toluene, acetaldehyde and formaldehyde (1.15E-02, 5.14E-03, 2.84E-04, and 2.52E-04, respectively). Three risk factors were investigated to reduce the total cancer risk levels: reducing the chemical concentration, exposure time and exposure duration. The use of a mask (chemical concentration) was the best way to reduce the risk to traffic police. However, the risk value of benzene (average 1.57E-05) was still higher than an acceptable value when using a mask.

The effects of repeated low-level blast exposure on hearing in marines

Directory of Open Access Journals (Sweden)

Lina R Kubli

2017-01-01

Full Text Available Background: The study evaluates a group of Military Service Members specialized in blast explosive training called “Breachers” who are routinely exposed to multiple low-level blasts while teaching breaching at the U.S. Marine Corps in Quantico Virginia. The objective of this study was to determine if there are any acute or long-term auditory changes due to repeated low-level blast exposures used in training. The performance of the instructor group “Breachers” was compared to a control group, “Engineers”. Methods: A total of 11 Breachers and four engineers were evaluated in the study. The participants received comprehensive auditory tests, including pure-tone testing, speech-in-noise (SIN measures, and central auditory behavioral and objective tests using early and late (P300 auditory evoked potentials over a period of 17 months. They also received shorter assessments immediately following the blast-exposure onsite at Quantico. Results: No acute or longitudinal effects were identified. However, there were some interesting baseline effects found in both groups. Contrary to the expected, the onsite hearing thresholds and distortion product otoacoustic emissions were slightly better at a few frequencies immediately after blast-exposure than measurements obtained with the same equipment weeks to months after each blast-exposure. Conclusions: To date, the current study is the most comprehensive study that evaluates the long-term effects of blast-exposure on hearing. Despite extensive testing to assess changes, the findings of this study suggest that the levels of current exposures used in this military training environment do not seem to have an obvious deleterious effect on hearing.

Low Level Exposure to GB Vapor in Air: Diagnosis/Dosimetry, Lowest Observable Effect Levels, Performance-Incapacitation, and Possible Delayed Effects

National Research Council Canada - National Science Library

1998-01-01

...: (I) A glass exposure chamber for whole-body exposure of unanesthetized guinea pigs and marmosets to low levels of OB vapor in air has been designed and constructed, and is in the implementation stage...

Radiation exposure of aircrew and passengers during some Czechoslovak airlines commercial flights

International Nuclear Information System (INIS)

Spurny, F.; Votockova, I.

1994-01-01

Radiation exposure of aircrew and passengers on boards of Czechoslovak Airlines (CSA) subsonic aircraft was studied. It was found that the exposure levels depends on flights altitude, changes also with geographical position (latitude and longitude). Measurements were performed during 1991 to 1993 years; i.e. at the period of sun maximum and immediately after it. Total dose equivalent rates did not exceed 10 μSv per hour of flight. An increasing of its level with decreasing sun activity has been already registered. (orig.)

Lifetime Exposure to Intimate Partner Violence and Proinflammatory Cytokine Levels Across the Perinatal Period.

Science.gov (United States)

Robertson Blackmore, Emma; Mittal, Mona; Cai, Xueya; Moynihan, Jan A; Matthieu, Monica M; O'Connor, Thomas G

2016-10-01

Intimate partner violence (IPV) is a public health concern, affecting one-third of US women. Prior research suggests an association between exposure to IPV and poor maternal perinatal health, but the underlying biological correlates are not well understood. This study examined the relationship between exposure to IPV and proinflammatory cytokine levels, a candidate mechanism accounting for poor psychiatric and obstetric outcomes, across the perinatal period. Data were obtained from a prospective, longitudinal cohort study of 171 women receiving obstetrical care from a hospital-based practice serving a predominantly low-income minority population. Participants completed questionnaires on IPV exposure, psychiatric symptoms, and psychosocial and obstetric factors and provided blood samples at 18 and 32 weeks of gestation and 6 weeks and 6 months postpartum. Serum levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) were assayed via enzyme-linked immunosorbent assay. Thirty-five (20.5%) women reported lifetime exposure to IPV and 7 (4.1%) reported being physically hurt in the preceding 12 months (4 while pregnant). Lifetime exposure to IPV was associated with increased likelihood of experiencing perinatal depression and smoking during pregnancy. Women with a history of IPV had significantly higher levels of TNF-α at 18 weeks (z = -2.29, p < 0.05), but significantly smaller changes in levels of IL-6 (β = -0.36, p = 0.04) across time. Lifetime exposure to IPV was associated with a range of adverse mental health outcomes and may affect proinflammatory cytokine levels in pregnancy.

Sea-Level Change in the Russian Arctic Since the Last Glacial Maximum

Science.gov (United States)

Horton, B.; Baranskaya, A.; Khan, N.; Romanenko, F. A.

2017-12-01

Relative sea-level (RSL) databases that span the Last Glacial Maximum (LGM) to present have been used to infer changes in climate, regional ice sheet variations, the rate and geographic source of meltwater influx, and the rheological structure of the solid Earth. Here, we have produced a quality-controlled RSL database for the Russian Arctic since the LGM. The database contains 394 index points, which locate the position of RSL in time and space, and 244 limiting points, which constrain the minimum or maximum limit of former sea level. In the western part of the Russian Arctic (Barents and White seas,) RSL was driven by glacial isostatic adjustment (GIA) due to deglaciation of the Scandinavian ice sheet, which covered the Baltic crystalline shield at the LGM. RSL data from isolation basins show rapid RSL from 80-100 m at 11-12 ka BP to 15-25 m at 4-5 ka BP. In the Arctic Islands of Franz-Joseph Land and Novaya Zemlya, RSL data from dated driftwood in raised beaches show a gradual fall from 25-35 m at 9-10 ka BP to 5-10 m at 3 ka BP. In the Russian plain, situated at the margins of the formerly glaciated Baltic crystalline shield, RSL data from raised beaches and isolation basins show an early Holocene rise from less than -20 m at 9-11 ka BP before falling in the late Holocene, illustrating the complex interplay between ice-equivalent meltwater input and GIA. The Western Siberian Arctic (Yamal and Gydan Peninsulas, Beliy Island and islands of the Kara Sea) was not glaciated at the LGM. Sea-level data from marine and salt-marsh deposits show RSL rise at the beginning of the Holocene to a mid-Holocene highstand of 1-5 m at 5-1 ka BP. A similar, but more complex RSL pattern is shown for Eastern Siberia. RSL data from the Laptev Sea shelf show RSL at -40- -45 m and 11-14 ka BP. RSL data from the Lena Delta and Tiksi region have a highstand from 5 to 1 ka BP. The research is supported by RSF project 17-77-10130

CURRENT LEVELS OF MEDICAL EXPOSURE IN RUSSIA

Directory of Open Access Journals (Sweden)

M. I. Balonov

2015-01-01

Full Text Available We considered conditions of patients’ medical radiation exposure in Russian diagnostic radiology and nuclear medicine basing on the data of our own research, of the Unified system of individual dose control and of some relevant literature. We analyzed the data on the number of diagnostic examinations, patients’ individual and collective doses and their distribution by examination types. Time trends of the studied parameters are presented for the period between 1999 and 2013. Current level of Russian patients’ medical exposure is the lowest over the whole observation period and one of the lowest among the developed countries. The annual number of X-ray diagnostic examinations is 1.8 per capita. In 2013 median effective dose of medical exposure per capita in Russia was 0.45 mSv and median dose per procedure was 0.25 mSv. The major contribution to collective dose of medical exposure was from computed tomography and radiography; the largest individual doses were caused by interventional radiology, computed X-Ray and nuclear medicine tomographic examinations. The range of median doses comprises about four orders of magnitude, i.e. from several microSv in dental X-ray examinations up to several tens of milliSv in interventional and multistage tomographic examinations. The median effective dose of adult patients increases by about an order of magnitude with each transition from dental X-ray examinations to conventional radiology and further to computed tomography and interventional radiology examinations. During interventional X-Ray examinations, absorbed skin doses at radiation beam entrance site may reach several Gray, which may lead to deterministic radiation effects in skin and subcutaneous tissues. Due to replacement of low-dose ‘functional’ nuclear medicine examinations with more informative modern scintigraphy and tomography examination, patient doses substantially increased over the last decade. With current trend for re-equipment of

Cold exposure lowers energy expenditure at the cellular level.

Science.gov (United States)

Park, Seyeon; Chun, Sohyun; Kim, Danuh

2013-06-01

Mitochondrial function is intimately involved in various metabolic processes and is therefore essential to maintain cell viability. Of particular importance is the fact that mitochondrial membrane potential (ΔΨm ) is coupled with oxidative phosphorylation to drive adenosine triphosphate (ATP) synthesis. We have examined the effects of cold temperature stress on ΔΨm and the role of cold temperature receptor expression on ΔΨm . Human bronchial endothelial cell line, BEAS-2B, and human embryonic kidney, HEK293, cell line were transfected with the gene for cold temperature responsive receptor protein TRPM8 or TRPA1, and exposed to cold temperature. ΔΨm was monitored using 5,5',6,6'-tetrachloro-1,1',3,3'-tetraethylbenzimidazoyl carbocyanine iodide derivative (JC-10), a ΔΨm probe. While cold temperatures significantly increased ΔΨm and mitochondrial ATP levels in cells transfected with temperature responsive receptor TRPM8 or TRPA1, no change was noted in wild-type cells. Moreover, the change in ΔΨm and ATP level was a dynamic process. ΔΨm was raised to peak levels within 10 min of cold exposure, followed by a return to baseline levels at 30 min. Our findings suggest that cold temperature exposure increased mitochondrial ΔΨm via a mechanism involving cold temperature receptors. © 2013 International Federation for Cell Biology.

Exposure to meat-derived carcinogens and bulky DNA adduct levels in normal-appearing colon mucosa.

Science.gov (United States)

Ho, Vikki; Brunetti, Vanessa; Peacock, Sarah; Massey, Thomas E; Godschalk, Roger W L; van Schooten, Frederik J; Ashbury, Janet E; Vanner, Stephen J; King, Will D

2017-09-01

Meat consumption is a risk factor for colorectal cancer. This research investigated the relationship between meat-derived carcinogen exposure and bulky DNA adduct levels, a biomarker of DNA damage, in colon mucosa. Least squares regression was used to examine the relationship between meat-derived carcinogen exposure (PhIP and meat mutagenicity) and bulky DNA adduct levels in normal-appearing colon tissue measured using 32 P-postlabelling among 202 patients undergoing a screening colonoscopy. Gene-diet interactions between carcinogen exposure and genetic factors relevant to biotransformation and DNA repair were also examined. Genotyping was conducting using the MassARRAY ® iPLEX ® Gold SNP Genotyping assay. PhIP and higher meat mutagenicity exposures were not associated with levels of bulky DNA adducts in colon mucosa. The XPC polymorphism (rs2228001) was found to associate with bulky DNA adduct levels, whereby genotypes conferring lower DNA repair activity were associated with higher DNA adduct levels than the normal activity genotype. Among individuals with genotypes associated with lower DNA repair (XPD, rs13181 and rs1799179) or detoxification activity (GSTP1, rs1695), higher PhIP or meat mutagenicity exposures were associated with higher DNA adduct levels. Significant interactions between the XPC polymorphism (rs2228000) and both dietary PhIP and meat mutagenicity on DNA adduct levels was observed, but associations were inconsistent with the a priori hypothesized direction of effect. Exposure to meat-derived carcinogens may be associated with increased DNA damage occurring directly in the colon among genetically susceptible individuals. Copyright © 2017 Elsevier B.V. All rights reserved.

Gestational exposure to high perchlorate concentrations in drinking water and neonatal thyroxine levels.

Science.gov (United States)

Amitai, Yona; Winston, Gary; Sack, Joseph; Wasser, Janice; Lewis, Matthew; Blount, Benjamin C; Valentin-Blasini, Liza; Fisher, Nirah; Israeli, Avi; Leventhal, Alex

2007-09-01

To assess the effect of gestational perchlorate exposure through drinking water on neonatal thyroxine (T(4)). T(4) values were compared among newborns in Ramat Hasharon, Israel, whose mothers resided in suburbs where drinking water contained perchlorate water exclusively (as determined by a telephone interview) were analyzed as a subset. Serum perchlorate levels in blood from donors residing in the area were used as proxy indicators of exposure. Neonatal T(4) values (mean +/- SD) in the very high, high, and low exposure groups were 13.9 +/- 3.8, 13.9 +/- 3.4, and 14.0 +/- 3.5 microg/dL, respectively (p = NS). Serum perchlorate concentrations in blood from donors residing in areas corresponding to these groups were 5.99 +/- 3.89, 1.19 +/- 1.37, and 0.44 +/- 0.55 microg/L, respectively. T(4) levels of neonates with putative gestational exposure to perchlorate in drinking water were not statistically different from controls. This study finds no change in neonatal T(4) levels despite maternal consumption of drinking water that contains perchlorate at levels in excess of the Environmental Protection Agency (EPA) drinking water equivalent level (24.5 microg/L) based on the National Research Council reference dose (RfD) [0.7 microg/(kg.day)]. Therefore the perchlorate RfD is likely to be protective of thyroid function in neonates of mothers with adequate iodide intake.

Effect of Low Level Cadmium Exposure on Superoxide Dismutase ...

African Journals Online (AJOL)

Purpose: To investigate the effect of low level cadmium (Cd) exposure on the activity of superoxide dismutase ... cancer, aging and a diversity of diseases [5]. Superoxide .... responsible for the long biological half-life of cadmium [12]. ... indicator of the balance between the damaging effects and the ... Scand J Work Environ.

A novel approach to estimating potential maximum heavy metal exposure to ship recycling yard workers in Alang, India

Energy Technology Data Exchange (ETDEWEB)

Deshpande, Paritosh C.; Tilwankar, Atit K.; Asolekar, Shyam R., E-mail: asolekar@iitb.ac.in

2012-11-01

The 180 ship recycling yards located on Alang-Sosiya beach in the State of Gujarat on the west coast of India is the world's largest cluster engaged in dismantling. Yearly 350 ships have been dismantled (avg. 10,000 ton steel/ship) with the involvement of about 60,000 workers. Cutting and scrapping of plates or scraping of painted metal surfaces happens to be the commonly performed operation during ship breaking. The pollutants released from a typical plate-cutting operation can potentially either affect workers directly by contaminating the breathing zone (air pollution) or can potentially add pollution load into the intertidal zone and contaminate sediments when pollutants get emitted in the secondary working zone and gets subjected to tidal forces. There was a two-pronged purpose behind the mathematical modeling exercise performed in this study. First, to estimate the zone of influence up to which the effect of plume would extend. Second, to estimate the cumulative maximum concentration of heavy metals that can potentially occur in ambient atmosphere of a given yard. The cumulative maximum heavy metal concentration was predicted by the model to be between 113 {mu}g/Nm{sup 3} and 428 {mu}g/Nm{sup 3} (at 4 m/s and 1 m/s near-ground wind speeds, respectively). For example, centerline concentrations of lead (Pb) in the yard could be placed between 8 and 30 {mu}g/Nm{sup 3}. These estimates are much higher than the Indian National Ambient Air Quality Standards (NAAQS) for Pb (0.5 {mu}g/Nm{sup 3}). This research has already become the critical science and technology inputs for formulation of policies for eco-friendly dismantling of ships, formulation of ideal procedure and corresponding health, safety, and environment provisions. The insights obtained from this research are also being used in developing appropriate technologies for minimizing exposure to workers and minimizing possibilities of causing heavy metal pollution in the intertidal zone of ship recycling

Low level exposure to chemicals and immune system

International Nuclear Information System (INIS)

Colosio, C.; Birindelli, S.; Corsini, E.; Galli, C.L.; Maroni, M.

2005-01-01

Industrialized countries are facing an increase of diseases attributable to an alteration of the immune system function, and concern is growing that this trend could be at least partially attributable to new and modified patterns of exposure to chemicals. Among chemicals matter of concern, pesticides can be included. The Authors have reviewed the existing evidence of pesticide immunotoxicity in humans, showing that existing data are inadequate to raise conclusions on the immunotoxic risk related to these compounds. The limits of existing studies are: poor knowledge on exposure levels, heterogeneity of the approach, and difficulty in giving a prognostic significance to the slight changes often observed. To overcome these limits, the Authors have proposed a tier approach, based on three steps: the first, addressed at pointing out a possible immunomodulation; the second, at refining the results and the third one, when needed, to finalize the study and to point out concordance with previous results. Studies should preferably be carried out through comparison of pre- and post-exposure findings in the same groups of subjects to be examined immediately after the end of the exposure. A simplification of the first step approach can be used by the occupational health physician and the occupational toxicologist. Conclusions on the prognostic significance of the slight changes often observed will be reached only by validating the hypothesis generated by field studies with an epidemiological approach. In this field, the most useful option is represented by longitudinal perspective studies

Levels of oxylipins, endocannabinoids and related lipids in plasma before and after low-level exposure to acrolein in healthy individuals and individuals with chemical intolerance.

Science.gov (United States)

Claeson, Anna-Sara; Gouveia-Figueira, Sandra; Häggström, Jenny; Fowler, Christopher J; Nording, Malin L

2017-06-01

Oxylipins and endocannabinoids play important biological roles, including effects upon inflammation. It is not known whether the circulating levels of these lipids are affected by inhalation of the environmental pollutant acrolein. In the present study, we have investigated the consequences of low-level exposure to acrolein on oxylipin, endocannabinoid and related lipid levels in the plasma of healthy individuals and individuals with chemical intolerance (CI), an affliction with a suggested inflammatory origin. Participants were exposed twice (60min) to heptane and a mixture of heptane and acrolein. Blood samples were collected before exposure, after and 24h post-exposure. There were no overt effects of acrolein exposure on the oxylipin lipidome or endocannibinoids detectable in the bloodstream at the time points investigated. No relationship between basal levels or levels after exposure to acrolein and CI could be identified. This implicates a minor role of inflammatory mediators on the systemic level in CI. Copyright © 2017 Elsevier Ltd. All rights reserved.

Chronic exposure to environmental levels of tribromophenol impairs zebrafish reproduction

International Nuclear Information System (INIS)

Deng Jun; Liu Chunsheng; Yu Liqin; Zhou Bingsheng

2010-01-01

Tribromophenol (2,4,6-TBP) is ubiquitously found in aquatic environments and biota. In this study, we exposed zebrafish embryos (F 0 ; 2'''' days post-fertilization, dpf) to environmental concentration (0.3 μg/L) and a higher concentration (3.0 μg/L) of TBP and assessed the impact of chronic exposure (120 dpf) on reproduction. TBP exposure did not cause a significant increase in the malformation and reduction in the survival in the F 0 -generation fish. After TBP exposure, the plasma testosterone and estradiol levels significantly increased in males and decreased in females. The transcription of steroidogenic genes (3β-HSD, 17β-HSD, CYP17, CYP19A, CYP19B) was significantly upregulated in the brain and testes in males and downregulated in the brain and ovary in females. TBP exposure significantly downregulated and upregulated the expression of VTG in the liver of female and male fish, respectively. Meanwhile, TBP exposure altered the sex ratio toward a male-dominant state. The F 1 -generation larvae exhibited increased malformation, reduced survival, and retarded growth, suggesting that TBP in the aquatic environment has significant adverse effects on fish population.

Exposure to DEHP decreased four fatty acid levels in plasma of prepartum mice

International Nuclear Information System (INIS)

Nakashima, Ryosuke; Hayashi, Yumi; Khalequzzaman, Md.; Jia, Xiaofang; Wang, Dong; Naito, Hisao; Ito, Yuki; Kamijima, Michihiro; Gonzalez, Frank J.; Nakajima, Tamie

2013-01-01

Maternal exposure to di(2-ethylhexyl) phthalate (DEHP) decreased the plasma triglyceride in prepartum mice. To identify the fatty acid (FA) species involved and to understand the underlying mechanisms, pregnant Sv/129 wild-type (mPPARα), peroxisome proliferator-activated receptor α-null (Pparα-null) and humanized PPARα (hPPARα) mice were treated with diets containing 0%, 0.01%, 0.05% or 0.1% DEHP. Dams were dissected on gestational day 18 together with fetuses, and on postnatal day 2 together with newborns. n-3/n-6 polyunsaturated, saturated, and monounsaturated FAs in maternal plasma and in liver of wild-type offspring, and representative enzymes for FA desaturation and elongation in maternal liver, were measured. The plasma levels of linoleic acid, α-linolenic acid, palmitic acid and oleic acid were higher in the pregnant control mPPARa mice than in Ppara-null and hPPARa mice. DEHP exposure significantly decreased the levels of these four FAs only in pregnant mPPARα mice. Plasma levels of many FAs were higher in pregnant mice than in postpartum ones in a genotype-independent manner, while it was lower in the livers of fetuses than pups. DEHP exposure slightly increased hepatic arachidonic acid, α-linolenic acid, palmitoleic acid and oleic acid in fetuses, but not in pups. However, DEHP exposure did not clearly influence FA desaturase 1 and 2 nor elongase 2 and 5 expressions in the liver of all maternal mice. Taken together, the levels of plasma four FAs with shorter carbon chains were higher in pregnant mPPARα mice than in other genotypes, and DEHP exposure decreased these specific FA concentrations only in mPPARα mice, similarly to triglyceride levels

Investigation on the acceptance level of radiation exposure. Comparison of Chinese and Japanese

International Nuclear Information System (INIS)

Wu, Jin; Katoh, Kazuaki

1999-01-01

Safety standards must be determined with the contract between a society and the person concerned, i.e. the agreement in a social community. Individual understandings on the (ionizing) radiation should be proper and uniform as far as possible, just in the case. The individual acceptable radiation dose level of a constituent of a community is one of the key roles for radiation managements and also coping with radiofobia (persons who have hatred and/or allergic syndromes for the radiation). The authors have obtained information by means of questionnaires on the acceptable dose levels of the radiation for 2 groups in a community, the one is a medical science group and the other is a science-technology group in both countries, China and Japan. The annual natural radiation dose etc. are described with inquiries to preclude meaningless responses. The levels of the acceptable radiation dose are different in individuals and show wide distributions. The gap between the two acceptable dose levels for a person is narrow, i.e. the one is the minimum radiation dose that a person rejects with dread and the other is the maximum dose that a person does not have any anxiety. The Japanese science-technology group shows the significant higher dose than that of the Chinese science-technology group. The Chinese medical science group shows the significant higher dose than that of the Chinese science-technology group. The Japanese medical science group does not show the statistically significant difference from the Japanese science-technology group. A perception for the radiation exposure and safety is unexpectedly scattered from person to person even though among the high-level intellectual groups mentioned above. There is no difference on this scattering between the Japan and China. (Y. Tanaka)

Mind-sets, low-level exposures, and research

International Nuclear Information System (INIS)

Sagan, L.A.

1993-01-01

Much of our environmental policy is based on the notion that carcinogenic agents are harmful at even minuscule doses. From where does this thinking come? What is the scientific evidence that supports such policy? Moreover, why is the public willing to buy into this? Or is it the other way around: Has the scientific community bought into a paradigm that has its origins in public imagery? Or, most likely, are there interactions between the two? It is essential that we find out whether or not there are risks associated with low-level exposures to radiation. The author can see three obvious areas where the future depends on better information: The increasing radiation exposures resulting from the use of medical diagnostic and therapeutic practices need to be properly evaluated for safety; Environmental policies, which direct enormous resources to the reduction of small radiation exposures, needs to be put on a firmer scientific basis; The future of nuclear energy, dependent as it is on public acceptance, may well rely upon a better understanding of low-dose effects. Nuclear energy could provide an important solution of global warming and other possible environmental hazards, but will probably not be implemented as long as fear of low-dose radiation persists. Although an established paradigm has great resilience, it cannot resist the onslaught of inconsistent scientific observations or of the social value system that supports it. Only new research will enable us to determine if a paradigm shift is in order here

Improved inhalation technology for setting safe exposure levels for workplace chemicals

Science.gov (United States)

Stuart, Bruce O.

1993-01-01

Threshold Limit Values recommended as allowable air concentrations of a chemical in the workplace are often based upon a no-observable-effect-level (NOEL) determined by experimental inhalation studies using rodents. A 'safe level' for human exposure must then be estimated by the use of generalized safety factors in attempts to extrapolate from experimental rodents to man. The recent development of chemical-specific physiologically-based toxicokinetics makes use of measured physiological, biochemical, and metabolic parameters to construct a validated model that is able to 'scale-up' rodent response data to predict the behavior of the chemical in man. This procedure is made possible by recent advances in personal computer software and the emergence of appropriate biological data, and provides an analytical tool for much more reliable risk evaluation and airborne chemical exposure level setting for humans.

Radiation exposure rate and liquid level measurement inside a high level liquid waste (HLLW) storage tank

International Nuclear Information System (INIS)

Sur, B.; Yue, S.; Thekkevarriam, A.

2007-01-01

An instrument based on an inexpensive, small silicon diode has been developed and used to measure, for the first time, the gamma radiation exposure rate profile inside a 6.4 mm diameter reentrant thermo-well tube, immersed in the highly radioactive liquid solution in an HLLW storage tank. The measurement agrees with previous calculations of exposure rate, and provides confirmation for safe and effective radiation work plans and material selection for investigations and remediation of the storage tank facility. The measured radiation exposure rate profile is also used to confirm that the position of tank internal structures have not changed because of aging and corrosion, and to obtain, within a few mm, the level of liquid inside the tank. (author)

Perinatal alcohol exposure enhances nocistatin levels in adulthood.

Science.gov (United States)

Tekes, Kornélia; Hantos, Mónika; Gyenge, Melinda; Csaba, Gyorgy

2007-06-01

In earlier experiments perinatal hormonal imprinting by alcohol decreased the hormone content of immune cells for life. In the present study, both a single day (15% on the third postnatal day) and a long-term treatment schedule of alcohol exposure (3% for 21 days) of dams during lactation significantly (P < 0.01) enhanced endogenous levels of nocistatin in the blood plasma as well as in the cerebrospinal fluid of the offspring, measured in 3-month-old rats. Our data suggest that alcohol consumption during lactation can cause a life-long influence on nocistatin levels in the offspring and most likely modify nocistatin-related functions such as pain tolerance.

Development of a source-exposure matrix for occupational exposure assessment of electromagnetic fields in the INTEROCC study.

Science.gov (United States)

Vila, Javier; Bowman, Joseph D; Figuerola, Jordi; Moriña, David; Kincl, Laurel; Richardson, Lesley; Cardis, Elisabeth

2017-07-01

To estimate occupational exposures to electromagnetic fields (EMF) for the INTEROCC study, a database of source-based measurements extracted from published and unpublished literature resources had been previously constructed. The aim of the current work was to summarize these measurements into a source-exposure matrix (SEM), accounting for their quality and relevance. A novel methodology for combining available measurements was developed, based on order statistics and log-normal distribution characteristics. Arithmetic and geometric means, and estimates of variability and maximum exposure were calculated by EMF source, frequency band and dosimetry type. The mean estimates were weighted by our confidence in the pooled measurements. The SEM contains confidence-weighted mean and maximum estimates for 312 EMF exposure sources (from 0 Hz to 300 GHz). Operator position geometric mean electric field levels for radiofrequency (RF) sources ranged between 0.8 V/m (plasma etcher) and 320 V/m (RF sealer), while magnetic fields ranged from 0.02 A/m (speed radar) to 0.6 A/m (microwave heating). For extremely low frequency sources, electric fields ranged between 0.2 V/m (electric forklift) and 11,700 V/m (high-voltage transmission line-hotsticks), whereas magnetic fields ranged between 0.14 μT (visual display terminals) and 17 μT (tungsten inert gas welding). The methodology developed allowed the construction of the first EMF-SEM and may be used to summarize similar exposure data for other physical or chemical agents.

Chronic exposure to low frequency noise at moderate levels causes impaired balance in mice.

Directory of Open Access Journals (Sweden)

Haruka Tamura

Full Text Available We are routinely exposed to low frequency noise (LFN; below 0.5 kHz at moderate levels of 60-70 dB sound pressure level (SPL generated from various sources in occupational and daily environments. LFN has been reported to affect balance in humans. However, there is limited information about the influence of chronic exposure to LFN at moderate levels for balance. In this study, we investigated whether chronic exposure to LFN at a moderate level of 70 dB SPL affects the vestibule, which is one of the organs responsible for balance in mice. Wild-type ICR mice were exposed for 1 month to LFN (0.1 kHz and high frequency noise (HFN; 16 kHz at 70 dB SPL at a distance of approximately 10-20 cm. Behavior analyses including rotarod, beam-crossing and footprint analyses showed impairments of balance in LFN-exposed mice but not in non-exposed mice or HFN-exposed mice. Immunohistochemical analysis showed a decreased number of vestibular hair cells and increased levels of oxidative stress in LFN-exposed mice compared to those in non-exposed mice. Our results suggest that chronic exposure to LFN at moderate levels causes impaired balance involving morphological impairments of the vestibule with enhanced levels of oxidative stress. Thus, the results of this study indicate the importance of considering the risk of chronic exposure to LFN at a moderate level for imbalance.

Consumer product exposures associated with urinary phthalate levels in pregnant women

OpenAIRE

Buckley, Jessie P.; Palmieri, Rachel T.; Matuszewski, Jeanine M.; Herring, Amy H.; Baird, Donna D.; Hartmann, Katherine E.; Hoppin, Jane A.

2012-01-01

Human phthalate exposure is ubiquitous, but little is known regarding predictors of urinary phthalate levels. To explore this, 50 pregnant women aged 18–38 years completed two questionnaires on potential phthalate exposures and provided a first morning void. Urine samples were analyzed for 12 phthalate metabolites. Associations with questionnaire items were evaluated via Wilcoxon tests and t-tests, and r-squared values were calculated in multiple linear regression models. Few measured factors...

Occupational exposure to mercury. What is a safe level?

OpenAIRE

Moienafshari, R.; Bar-Oz, B.; Koren, G.

1999-01-01

QUESTION: One of my pregnant patients, a dental hygienist, uses mercury in her workplace, but appears to have no symptoms of mercury toxicity. She has heard that mercury might affect her fetus. What should I recommend to her? What is a safe level of mercury in the air for pregnant women? ANSWER: Testing for levels of mercury in whole blood and, preferably, urine is useful for confirming exposure. Currently, mercury vapour concentrations greater than 0.01 mg/m3 are considered unsafe. Also, wom...

Exposure to pyrethroids insecticides and serum levels of thyroid-related measures in pregnant women

International Nuclear Information System (INIS)

Zhang, Jie; Hisada, Aya; Yoshinaga, Jun; Shiraishi, Hiroaki; Shimodaira, Kazuhisa; Okai, Takashi; Noda, Yumiko; Shirakawa, Miyako; Kato, Nobumasa

2013-01-01

Possible association between environmental exposure to pyrethroid insecticides and serum thyroid-related measures was explored in 231 pregnant women of 10–12 gestational weeks recruited at a university hospital in Tokyo during 2009–2011. Serum levels of free thyroxine (fT4), thyroid stimulating hormone (TSH) and thyroid biding globulin (TBG) and urinary pyrethroid insecticide metabolite (3-phenoxybenzoic acid, 3-PBA) were measured. Obstetrical information was obtained from medical records and dietary and lifestyle information was collected by self-administered questionnaire. Geometric mean concentration of creatinine-adjusted urinary 3-PBA was 0.363 (geometric standard deviation: 3.06) μg/g cre, which was consistent with the previously reported levels for non-exposed Japanese adult females. The range of serum fT4, TSH and TBG level was 0.83–3.41 ng/dL, 0.01–27.4 μIU/mL and 16.4–54.4 μg/mL, respectively. Multiple regression analysis was carried out by using either one of serum levels of thyroid-related measures as a dependent variable and urinary 3-PBA as well as other potential covariates (age, pre-pregnancy BMI, parity, urinary iodine, smoking and drinking status) as independent variables: 3-PBA was not found as a significant predictor of serum level of thyroid-related measures. Lack of association may be due to lower pyrethroid insecticide exposure level of the present subjects. Taking the ability of pyrethroid insecticides and their metabolite to bind to nuclear thyroid hormone (TH) receptor, as well as their ability of placental transfer, into consideration, it is warranted to investigate if pyrethroid pesticides do not have any effect on TH actions in fetus brain even though maternal circulating TH level is not affected. -- Highlights: • Pyrethroid exposure and thyroid hormone status was examined in pregnant women. • Urinary 3-phenoxybenzoic acid was used as a biomarker of exposure. • Iodine nutrition, age and other covariates were included

Exposure to pyrethroids insecticides and serum levels of thyroid-related measures in pregnant women

Energy Technology Data Exchange (ETDEWEB)

Zhang, Jie; Hisada, Aya [Department of Environmental Studies, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563 (Japan); Yoshinaga, Jun, E-mail: junyosh@k.u-tokyo.ac.jp [Department of Environmental Studies, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8563 (Japan); Shiraishi, Hiroaki [National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki 305-8563 (Japan); Shimodaira, Kazuhisa; Okai, Takashi [Department of Obstetrics and Gynecology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan); Noda, Yumiko; Shirakawa, Miyako; Kato, Nobumasa [Department of Psychiatry and Neurology, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa, Tokyo 142-8555 (Japan)

2013-11-15

Possible association between environmental exposure to pyrethroid insecticides and serum thyroid-related measures was explored in 231 pregnant women of 10–12 gestational weeks recruited at a university hospital in Tokyo during 2009–2011. Serum levels of free thyroxine (fT4), thyroid stimulating hormone (TSH) and thyroid biding globulin (TBG) and urinary pyrethroid insecticide metabolite (3-phenoxybenzoic acid, 3-PBA) were measured. Obstetrical information was obtained from medical records and dietary and lifestyle information was collected by self-administered questionnaire. Geometric mean concentration of creatinine-adjusted urinary 3-PBA was 0.363 (geometric standard deviation: 3.06) μg/g cre, which was consistent with the previously reported levels for non-exposed Japanese adult females. The range of serum fT4, TSH and TBG level was 0.83–3.41 ng/dL, 0.01–27.4 μIU/mL and 16.4–54.4 μg/mL, respectively. Multiple regression analysis was carried out by using either one of serum levels of thyroid-related measures as a dependent variable and urinary 3-PBA as well as other potential covariates (age, pre-pregnancy BMI, parity, urinary iodine, smoking and drinking status) as independent variables: 3-PBA was not found as a significant predictor of serum level of thyroid-related measures. Lack of association may be due to lower pyrethroid insecticide exposure level of the present subjects. Taking the ability of pyrethroid insecticides and their metabolite to bind to nuclear thyroid hormone (TH) receptor, as well as their ability of placental transfer, into consideration, it is warranted to investigate if pyrethroid pesticides do not have any effect on TH actions in fetus brain even though maternal circulating TH level is not affected. -- Highlights: • Pyrethroid exposure and thyroid hormone status was examined in pregnant women. • Urinary 3-phenoxybenzoic acid was used as a biomarker of exposure. • Iodine nutrition, age and other covariates were included

Cognitive consequences of novelty and familiarity: how mere exposure influences level of construal

NARCIS (Netherlands)

Förster, J.

2009-01-01

Two experiments examine whether frequency of exposure influences level of construal. Using subliminal presentation, participants were exposed to neutral, unknown letters 0, 5, 15, or 40 times, and a typical mere exposure effect was found on evaluation. However, we hypothesized and showed in

Contribution to the study of maximum levels for liquid radioactive waste disposal into continental and sea water. Treatment of some typical samples

International Nuclear Information System (INIS)

Bittel, R.; Mancel, J.

1968-10-01

The most important carriers of radioactive contamination of man are the whole of foodstuffs and not only ingested water or inhaled air. That is the reason why, in accordance with the spirit of the recent recommendations of the ICRP, it is proposed to substitute the idea of maximum levels of contamination of water to the MPC. In the case of aquatic food chains (aquatic organisms and irrigated foodstuffs), the knowledge of the ingested quantities and of the concentration factors food/water permit to determinate these maximum levels, or to find out a linear relation between the maximum levels in the case of two primary carriers of contamination (continental and sea waters). The notion of critical food-consumption, critical radioelements and formula of waste disposal are considered in the same way, taking care to attach the greatest possible importance to local situations. (authors) [fr

Lake-level increasing under the climate cryoaridization conditions during the Last Glacial Maximum

Science.gov (United States)

Amosov, Mikhail; Strelkov, Ivan

2017-04-01

A lake genesis and lake-level increasing during the Last Glacial Maximum (LGM) are the paramount issues in paleoclimatology. Investigating these problems reveals the regularities of lake development and figures out an arid territory conditions at the LGM stage. Pluvial theory is the most prevalent conception of lake formation during the LGM. This theory is based on a fact that the water bodies emerged and their level increased due to torrential rainfalls. In this study, it is paid attention to an alternative assumption of lake genesis at the LGM stage, which is called climate cryoaridization. In accordance with this hypothesis, the endorheic water basins had their level enlarged because of a simultaneous climate aridity and temperature decrease. In this research, a lake-level increasing in endorheic regions of Central Asia and South American Altiplano of the Andes is described. The lake investigation is related to its conditions during the LGM. The study also includes a lake catalogue clearly presenting the basin conditions at the LGM stage and nowadays. The data compilation partly consists of information from an earlier work of Mikhail Amosov, Lake-levels, Vegetation And Climate In Central Asia During The Last Glacial Maximum (EGU2014-3015). According to the investigation, a lake catalogue on 27 lakes showed that most of the water bodies had higher level. This feature could be mentioned for the biggest lakes of the Aral Sea, Lake Balkhash, Issyk-Kul etc. and for the small ones located in the mountains, such as Pamir, Tian-Shan and Tibet. Yet some lakes that are situated in Central Asian periphery (Lake Qinghai and lakes in Inner Mongolia) used to be lower than nowadays. Also, the lake-level increasing of Altiplano turned to be a significant feature during the LGM in accordance with the data of 5 lakes, such as Titicaca, Coipasa-Uyuni, Lejia, Miscanti and Santa-Maria. Most of the current endorheic basins at the LGM stage were filled with water due to abundant

The relationship between blood lead levels and occupational exposure in a pregnant population

OpenAIRE

Osmel La-Llave-León; José Manuel Salas Pacheco; Sergio Estrada Martínez; Eloísa Esquivel Rodríguez; Francisco X. Castellanos Juárez; Ada Sandoval Carrillo; Angélica María Lechuga Quiñones; Fernando Vázquez Alanís; Gonzalo García Vargas; Edna Madai Méndez Hernández; Jaime Duarte Sustaita

2016-01-01

Background Pregnant women exposed to lead are at risk of suffering reproductive damages, such as miscarriage, preeclampsia, premature delivery and low birth weight. Despite that the workplace offers the greatest potential for lead exposure, there is relatively little information about occupational exposure to lead during pregnancy. This study aims to assess the association between blood lead levels and occupational exposure in pregnant women from Durango, Mexico. Methods A cross-sectional stu...

Using a network-based approach and targeted maximum likelihood estimation to evaluate the effect of adding pre-exposure prophylaxis to an ongoing test-and-treat trial.

Science.gov (United States)

Balzer, Laura; Staples, Patrick; Onnela, Jukka-Pekka; DeGruttola, Victor

2017-04-01

Several cluster-randomized trials are underway to investigate the implementation and effectiveness of a universal test-and-treat strategy on the HIV epidemic in sub-Saharan Africa. We consider nesting studies of pre-exposure prophylaxis within these trials. Pre-exposure prophylaxis is a general strategy where high-risk HIV- persons take antiretrovirals daily to reduce their risk of infection from exposure to HIV. We address how to target pre-exposure prophylaxis to high-risk groups and how to maximize power to detect the individual and combined effects of universal test-and-treat and pre-exposure prophylaxis strategies. We simulated 1000 trials, each consisting of 32 villages with 200 individuals per village. At baseline, we randomized the universal test-and-treat strategy. Then, after 3 years of follow-up, we considered four strategies for targeting pre-exposure prophylaxis: (1) all HIV- individuals who self-identify as high risk, (2) all HIV- individuals who are identified by their HIV+ partner (serodiscordant couples), (3) highly connected HIV- individuals, and (4) the HIV- contacts of a newly diagnosed HIV+ individual (a ring-based strategy). We explored two possible trial designs, and all villages were followed for a total of 7 years. For each village in a trial, we used a stochastic block model to generate bipartite (male-female) networks and simulated an agent-based epidemic process on these networks. We estimated the individual and combined intervention effects with a novel targeted maximum likelihood estimator, which used cross-validation to data-adaptively select from a pre-specified library the candidate estimator that maximized the efficiency of the analysis. The universal test-and-treat strategy reduced the 3-year cumulative HIV incidence by 4.0% on average. The impact of each pre-exposure prophylaxis strategy on the 4-year cumulative HIV incidence varied by the coverage of the universal test-and-treat strategy with lower coverage resulting in a larger

Cigarette smoking increases radon working level exposures to all occupants of the smoker's home

International Nuclear Information System (INIS)

Johnson, R.H. Jr.; Rosario, A. Jr.

1990-01-01

This paper reports that the 1988 National Academy of Sciences report on radon health risks evaluated the combined effects of radon exposures and cigarettes on the lung cancer risk to smokers. This report showed that the risk of lung cancer is about 10 times greater for smokers than for nonsmokers at the same Working Level exposures. In 1986, the Surgeon General reported that 106,000 lung cancer deaths occurred among smokers. Therefore, the health risks of cigarettes alone or in combination with radon exposures are well recognized. What has not been studied is the effect of cigarette smoke on the Working Levels in homes that increases the exposure to radon decay products to all occupants, both smokers and nonsmokers. Preliminary studies in a radon chamber at Radon QC showed that the smoke from a single cigarette increased the Working Levels by a factor of five within four hours. Furthermore, the Working Levels remained at an elevated level for more than 24 hours. The equilibrium ratio of radon decay products to radon gas also went from about 14% up to 71%, with a slow decrease over 24 hours. Similar studies in the homes of a smoker and nonsmoker confirmed the laboratory observations. The studies in homes also showed the effects of thoron decay products

Strategies to reduce exposure of fumonisins from complementary foods in rural Tanzania.

Science.gov (United States)

Kimanya, Martin E; De Meulenaer, Bruno; Van Camp, John; Baert, Katleen; Kolsteren, Patrick

2012-10-01

Feeding infants with maize can expose them to fumonisin mycotoxins. We assessed fumonisin exposure from complementary foods in rural Tanzania and determined strategies to reduce the exposure. We conducted a cross-sectional study in four villages of Tarakea division, Northern Tanzania. We used a repeat 24-hour dietary recall to collect data of maize consumption as complementary food for 254 infants aged 6-8 months. Fumonisin concentrations in the maize were also estimated. Fumonisin exposure was assessed using @risk analysis software. With the software, several maximum fumonisin contamination and maize consumption patterns were combined in order to determine effective strategies for minimizing fumonisin exposure. Of the infants, 89% consumed maize at amounts up to 158g/person/day (mean; 43g/person/day±28). The maize was contaminated with fumonisins at levels up to 3201µgkg(-1) . Risk of fumonisin intake above the provisional maximum tolerable daily limit of 2µgkg(-1) body weight was 15% (95% confidence interval; 10-19). The risk was minimized when the maximum contamination was set at 150µgkg(-1) . The risk was also minimized when the maximum consumption was set at 20g/child/day while keeping the maximum contamination at the European Union (EU) maximum tolerated limit (MTL) of 1000µgkg(-1) . Considering the economical and technological limitations of adopting good agricultural practices in rural Tanzania, it is practically difficult to reduce contamination in maize to 150µgkg(-1) . We suggest adoption of the EU MTL of 1000µgkg(-1) for fumonisins in maize and reduction, by replacement with another cereal, of the maize component in complementary foods to a maximum intake of 20g/child/day. © 2011 Blackwell Publishing Ltd.

Prenatal Earthquake Exposure and Midlife Uric Acid Levels Among Chinese Adults.

Science.gov (United States)

Ji, Chunpeng; Li, Yanping; Cui, Liufu; Cai, Jianfang; Shi, Jihong; Cheng, Feon W; Li, Yuqing; Curhan, Gary C; Wu, Shouling; Gao, Xiang

2017-05-01

To test whether prenatal exposure to earthquake (as a surrogate for acute prenatal stress) could have unfavorable effects on uric acid levels later in life. We included 536 individuals who had been prenatally exposed to the Tangshan earthquake in 1976, and 536 sex- and age-matched individuals without that exposure. Serum uric acid concentrations were measured based on fasting blood samples, which were repeatedly collected in 2006, 2008, and 2010. Mean uric acid concentrations in 2010 and the increasing rate from 2006 to 2010 were compared between the 2 groups, after adjustment for age, sex, body mass index, serum concentrations of glucose, triglycerides, C-reactive protein level, estimated glomerular filtration rate, and other potential confounders. We also used multiple logistic regression to estimate the risk of hyperuricemia (>416 μmole/liter in men or >357 μmole/liter in women) in 2010 by calculating the odds ratios (ORs) and 95% confidence intervals (95% CIs) after adjustment for the previously mentioned covariates. Participants with prenatal exposure to the earthquake had higher concentrations of serum uric acid (adjusted means 315 μmole/liter versus 296 μmole/liter; P = 0.001) and a higher likelihood of having hyperuricemia (multivariate adjusted OR 1.70 [95% CI 1.09-2.66]) in 2010 relative to those without the exposure. Prenatal exposure to the earthquake was consistently significantly associated with a faster increase in uric acid concentration from 2006 to 2010 (P earthquake was associated with higher serum uric acid and higher odds of hyperuricemia in early adulthood. © 2016, American College of Rheumatology.

Toxicity levels to humans during acute exposure to hydrogen fluoride

International Nuclear Information System (INIS)

Halton, D.M.; Dranitsaris, P.; Baynes, C.J.

1984-11-01

A literature review was conducted of the acute toxicity of hydrogen fluoride (HF) with emphasis on the effects of inhalation of gaseous HF. The data and findings of the relevant references were summarized under four categories: animal studies, controlled human studies, community exposure and industrial exposure. These were critically reviewed and then lethal concentration-time relationships were developed for humans, corresponding to LCsub(LO), LCsub(10) and LCsub(50) levels. The effects of age, health and other physiological variables on the sensitivity to HF were discussed, as well as antagonistic and synergistic effects with other substances

Operator dependency of the radiation exposure in cardiac interventions: feasibility of ultra low dose levels

International Nuclear Information System (INIS)

Emre Ozpelit, Mehmet; Ercan, Ertugrul; Pekel, Nihat; Tengiz, Istemihan; Yilmaz, Akar; Ozpelit, Ebru; Ozyurtlu, Ferhat

2017-01-01

Introduction: Mean radiation exposure in invasive cardiology varies greatly between different centres and interventionists. The International Commission on Radiological Protection and the EURATOM Council stipulate that, despite reference values, 'All medical exposure for radiodiagnostic purposes shall be kept as low as reasonably achievable' (ALARA). The purpose of this study is to establish the effects of the routine application of ALARA principles and to determine operator and procedure impact on radiation exposure in interventional cardiology. Materials and methods: A total of 240 consecutive cardiac interventional procedures were analysed. Five operators performed the procedures, two of whom were working in accordance with ALARA principles (Group 1 operators) with the remaining three working in a standard manner (Group 2 operators). Radiation exposure levels of these two groups were compared. Results: Total fluoroscopy time and the number of radiographic runs were similar between groups. However, dose area product and cumulative dose were significantly lower in Group 1 when compared with Group 2. Radiation levels of Group 1 were far below even the reference levels in the literature, thus representing an ultra-low-dose radiation exposure in interventional cardiology. Conclusion: By use of simple radiation reducing techniques, ultra-low-dose radiation exposure is feasible in interventional cardiology. Achievability of such levels depends greatly on operator awareness, desire, knowledge and experience of radiation protection. (authors)

Outdoor radiofrequency radiation levels in the West Bank-Palestine.

Science.gov (United States)

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).

A trial epidemiological study on health effects of long term and low level radiation exposure

International Nuclear Information System (INIS)

Hattori, Yoshiaki; Maeda, Kazuho

1980-01-01

As a trial evaluation of applicability of multivariate model in an analysis of health effects of radiation workers, the multiple logistic function method was applied to the data of occupational exposure record and long term absence record obtained from 593 employees of two institutions both of which practice R and D relating nuclear power. In order to estimate parameters of multiple logistic function by maximum likelihood method, followings were defined as variables: age, length of employment and cumulative exposure dose of radiation as independent variables, and the fact that whether the individual worker had the experience of absence lasting more than a week or not as a dependent variable. As the results, due to shortage of amount of data, only the age of workers shows a significant relationship with the absence data, the other variables do not have any significant results in the association with absence. In this preliminary trial, the applicability of multiple logistic function model in risk estimation of long term occupational exposure was not clearly demonstrated because of data shortage. To testify the applicability, further investigations will be needed, accumulating plenty of data concerning exposure and health effects. (author)

Common sole larvae survive high levels of pile-driving sound in controlled exposure experiments.

Directory of Open Access Journals (Sweden)

Loes J Bolle

Full Text Available In view of the rapid extension of offshore wind farms, there is an urgent need to improve our knowledge on possible adverse effects of underwater sound generated by pile-driving. Mortality and injuries have been observed in fish exposed to loud impulse sounds, but knowledge on the sound levels at which (sub-lethal effects occur is limited for juvenile and adult fish, and virtually non-existent for fish eggs and larvae. A device was developed in which fish larvae can be exposed to underwater sound. It consists of a rigid-walled cylindrical chamber driven by an electro-dynamical sound projector. Samples of up to 100 larvae can be exposed simultaneously to a homogeneously distributed sound pressure and particle velocity field. Recorded pile-driving sounds could be reproduced accurately in the frequency range between 50 and 1000 Hz, at zero to peak pressure levels up to 210 dB re 1µPa(2 (zero to peak pressures up to 32 kPa and single pulse sound exposure levels up to 186 dB re 1µPa(2s. The device was used to examine lethal effects of sound exposure in common sole (Solea solea larvae. Different developmental stages were exposed to various levels and durations of pile-driving sound. The highest cumulative sound exposure level applied was 206 dB re 1µPa(2s, which corresponds to 100 strikes at a distance of 100 m from a typical North Sea pile-driving site. The results showed no statistically significant differences in mortality between exposure and control groups at sound exposure levels which were well above the US interim criteria for non-auditory tissue damage in fish. Although our findings cannot be extrapolated to fish larvae in general, as interspecific differences in vulnerability to sound exposure may occur, they do indicate that previous assumptions and criteria may need to be revised.

Worker exposures from recycling surface contaminated radioactive scrap metal

International Nuclear Information System (INIS)

Kluk, A.; Phillips, J.W.; Culp, J.

1996-01-01

Current DOE policy permits release from DOE control of real property with residual levels of surficial radioactive contamination if the contamination is below approved guidelines. If the material contains contamination that is evenly distributed throughout its volume (referred to as volumetric contamination), then Departmental approval for release must be obtained in advance. Several DOE sites presently recycle surface contaminated metal, although the quantities are small relative to the quantities of metal processed by typical mini-mills, hence the potential radiation exposures to mill workers from processing DOE metals and the public from the processed metal are at present also a very small fraction of their potential value. The exposures calculated in this analysis are based on 100% of the scrap metal being processed at the maximum contamination levels and are therefore assumed to be maximum values and not likely to occur in actual practice. This paper examines the relationship between the surface contamination limits established under DOE Order 5400.5, open-quotes Radiation Protection of the Public and the Environment,close quotes and radiation exposures to workers involved in the scrap metal recycling process. The analysis is limited to surficial contamination at or below the guideline levels established in DOE Order 5400.5 at the time of release. Workers involved in the melting and subsequent fabrication of products are not considered radiation workers (no requirements for monitoring) and must be considered members of the public. The majority of the exposures calculated in this analysis range from tenths of a millirem per year (mrem/yr) to less than 5 mrem/yr. The incremental risk of cancer associated with these exposures ranges from 10 -8 cancers per year to 10 -6 cancers per year

Use of dose constraints in medical exposure

International Nuclear Information System (INIS)

Mutanga, N. V. T.

2013-04-01

Medical-related radiation is the largest source of controllable radiation exposure to humans and it accounts for more than 95% of radiation exposure from man-made sources. Medical exposure to radiation is exposure incurred by patients as part of their own medical or dental diagnosis or treatment; by persons, other than those occupationally exposed, knowingly, while voluntarily helping in the support and comfort of patients; and by volunteers in a programme of biomedical research involving their exposure. Because it is planned exposure, medical exposure has to conform to a set of principles of protection that apply equally to all controllable exposure situations: the principle of justification, the principle of optimisation of protection, and the principle of application of limits on maximum doses in planned situations. In this study the concept of dose constraints is being scrutinized to see if it can be applied in medical exposures and the benefits of such restrictions. Dose constraints can only be applied to exposure to persons voluntary helping in the support and comfort of patients as well as volunteers in the programme of biomedical research. There are no dose constraints for patients but the concept of reference levels applies. (au)

Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells

International Nuclear Information System (INIS)

Kang, Kyoung Ah; Lee, Hyung Chul; Lee, Je-Jung

2014-01-01

The objective of this study was to investigate the effects of the combined RF radiation (837 MHz CDMA plus 1950 MHz WCDMA) signal on levels of intracellular reactive oxygen species (ROS) in neuronal cells. Exposure of the combined RF signal was conducted at specific absorption rate values of 2 W/kg of CDMA plus 2 W/kg of WCDMA for 2 h. Co-exposure to combined RF radiation with either H 2 O 2 or menadione was also performed. The experimental exposure groups were incubator control, sham-exposed, combined RF radiation-exposed with or without either H 2 O 2 or menadione groups. The intracellular ROS level was measured by flow cytometry using the fluorescent probe dichlorofluorescein diacetate. Intracellular ROS levels were not consistently affected by combined RF radiation exposure alone in a time-dependent manner in U87, PC12 or SH-SY5Y cells. In neuronal cells exposed to combined RF radiation with either H 2 O 2 or menadione, intracellular ROS levels showed no statically significant alteration compared with exposure to menadione or H 2 O 2 alone. These findings indicate that neither combined RF radiation alone nor combined RF radiation with menadione or H 2 O 2 influences the intracellular ROS level in neuronal cells such as U87, PC12 or SH-SY5Y. (author)

Patient dose, gray level and exposure index with a computed radiography system

Science.gov (United States)

Silva, T. R.; Yoshimura, E. M.

2014-02-01

Computed radiography (CR) is gradually replacing conventional screen-film system in Brazil. To assess image quality, manufactures provide the calculation of an exposure index through the acquisition software of the CR system. The objective of this study is to verify if the CR image can be used as an evaluator of patient absorbed dose too, through a relationship between the entrance skin dose and the exposure index or the gray level values obtained in the image. The CR system used for this study (Agfa model 30-X with NX acquisition software) calculates an exposure index called Log of the Median (lgM), related to the absorbed dose to the IP. The lgM value depends on the average gray level (called Scan Average Level (SAL)) of the segmented pixel value histogram of the whole image. A Rando male phantom was used to simulate a human body (chest and head), and was irradiated with an X-ray equipment, using usual radiologic techniques for chest exams. Thermoluminescent dosimeters (LiF, TLD100) were used to evaluate entrance skin dose and exit dose. The results showed a logarithm relation between entrance dose and SAL in the image center, regardless of the beam filtration. The exposure index varies linearly with the entrance dose, but the angular coefficient is beam quality dependent. We conclude that, with an adequate calibration, the CR system can be used to evaluate the patient absorbed dose.

Exposure levels of farmers and veterinarians to particulate matter and gases uring operational tasks in pig-fattening houses

Directory of Open Access Journals (Sweden)

Nele Van Ransbeeck

2014-09-01

Full Text Available The main objective of the study was to assess particulate matter (PM exposure levels for both the farmer and the veterinarian during different operational tasks in pig-fattening houses, and to estimate their exposure levels on a daily working basis (time-weighted average (TWA. The measured PM fractions were: inhalable and respirable PM, PM10, PM2.5 and PM1. The effects of pig age, pen floor type (conventional or low emission surface and cleaning of the pens on the personal PM exposure were also investigated. Indoor concentrations of NH[sub]3[/sub], CH[sub]4[/sub], and CO[sub]2[/sub] were additionally measured during some operational tasks. The results showed that personal exposure levels can become extremely high during some operational tasks performed by the farmer or veterinarian. The highest concentration levels were observed during feed shovelling and blood sampling, the lowest during the weighing of the pigs. For the farmer, the estimated TWA exposure levels of inhalable and respirable PM were 6.0 and 0.29 mg m[sup] -3[/sup] , respectively. These exposure levels for the veterinarian were, respectively, 10.6 and 0.74 mg m[sup] -3[/sup] . The PM concentration levels were mainly determined by the performed operational tasks. There was no significant effect of pig age, pen floor type, nor cleaning of the pens on the personal exposure levels.

1991 implementation of As Low As Reasonably Achievable (ALARA) administrative radiation exposure levels: Experiences and lessons learned

International Nuclear Information System (INIS)

Aldridge, T.L.; Baumann, B.L.

1993-06-01

As Low As Reasonably Achievable (ALARA) radiation exposure levels were implemented on January 1, 1991, by Westinghouse Hanford Company (WHC), a prime US Department of Energy (DOE) contractor, located in Richland, Washington. This paper describes the radiation exposure levels which were implemented and the associated experiences and lessons learned. The issue of a report from the Committee on Biological Effectiveness of Ionizing Radiation in 1989 prompted DOE to re-evaluate its position on radiation exposure limits and the resulting doses received by occupational radiation workers. DOE requested that all it's contractors determine the impacts to operations from reduced radiation exposure levels

An investigation of the maximum penetration level of a photovoltaic (PV) system into a traditional distribution grid

Science.gov (United States)

Chalise, Santosh

Although solar photovoltaic (PV) systems have remained the fastest growing renewable power generating technology, variability as well as uncertainty in the output of PV plants is a significant issue. This rapid increase in PV grid-connected generation presents not only progress in clean energy but also challenges in integration with traditional electric power grids which were designed for transmission and distribution of power from central stations. Unlike conventional electric generators, PV panels do not have rotating parts and thus have no inertia. This potentially causes a problem when the solar irradiance incident upon a PV plant changes suddenly, for example, when scattered clouds pass quickly overhead. The output power of the PV plant may fluctuate nearly as rapidly as the incident irradiance. These rapid power output fluctuations may then cause voltage fluctuations, frequency fluctuations, and power quality issues. These power quality issues are more severe with increasing PV plant power output. This limits the maximum power output allowed from interconnected PV plants. Voltage regulation of a distribution system, a focus of this research, is a prime limiting factor in PV penetration levels. The IEEE 13-node test feeder, modeled and tested in the MATLAB/Simulink environment, was used as an example distribution feeder to analyze the maximum acceptable penetration of a PV plant. The effect of the PV plant's location was investigated, along with the addition of a VAR compensating device (a D-STATCOM in this case). The results were used to develop simple guidelines for determining an initial estimate of the maximum PV penetration level on a distribution feeder. For example, when no compensating devices are added to the system, a higher level of PV penetration is generally achieved by installing the PV plant close to the substation. The opposite is true when a VAR compensator is installed with the PV plant. In these cases, PV penetration levels over 50% may be

Effects of embryonic and fetal exposure to x-ray, microwaves, and ultrasound

International Nuclear Information System (INIS)

Brent, R.L.

1986-01-01

Many professionals are unfamiliar with radiation biology or the quantitative nature of the risks. Frequently, microwave, ultrasound, and ionizing radiation risks are confused. Although it is impossible to prove no risk for any environmental hazard, it appears that exposure to microwave radiation below the maximal permissible levels present no measurable risk to the embryo. Ultrasound exposure from diagnostic ultrasonographic imaging equipment also is quite innocuous. It is true that continued surveillance and research into potential risks of these low-level exposures should continue, but at present ultrasound not only improves obstetric care but also reduces the necessity of diagnostic x-ray procedures. In the field of ionizing radiation, we have as good a comprehension of the biologic effects and the quantitative maximum risks as of any other environmental hazard. Although the animal and human data support the conclusion that no increases in the incidence of gross congenital malformations, intrauterine growth retardation, or abortion will occur with exposures less than 5 rad, that does not mean that there are definitely no risks to the embryo exposed to lower doses of radiation. Whether there exists a linear or exponential dose-response relationship or a threshold exposure for genetic, carcinogenic, cell-depleting, and life-shortening effects has not been determined. In establishing maximum permissible levels for the embryo at low exposures, refer to Tables 4, 5, 6, 8, and 9. It is obvious that the risks of 1-rad or 5-rad acute exposure are far below the spontaneous risks of the developing embryo because 15 per cent of human embryos abort, 2.7 to 3.0 per cent of human embryos have major malformations, 4 per cent have intrauterine growth retardation, and 8 to 10 per cent have early- or late-onset genetic disease. 98 references

Occupational radiation exposure in the GDR in 1977

International Nuclear Information System (INIS)

Poulheim, K.F.; Rothe, W.; Scheler, R.

1980-01-01

In 1977, radiation workers were monitored for external and internal radiation exposure on the basis of film badges (37,348 persons), measurements with a whole-body counter (198 persons) and analyses of biosamples (174 persons). According to the film badge data, the monthly over-exposures (more than 4 mGy) totalled 253. In 6 cases the monthly exposure exceeded 30 mGy and the 9 highest annual exposure values were in the range of 50 to 120 mGy. Also, annual collective and annual per caput doses have been given for the exposed population as a whole and some subgroups. Based on model considerations, the internal radiation exposure situation resulting from unintentional intakes of radionuclides has been assessed in terms of committed dose equivalents to members of two selected groups of radiation workers: (a) persons with more-than-average internal contamination levels; (b) persons subjected to frequent individual monitoring. Except for some organ doses, the individual radiation exposure was below one-tenth the maximum permissible dose. (author)

Is beryllium-induced lung cancer caused only by soluble forms and high exposure levels?

Science.gov (United States)

Schubauer-Berigan, Mary K; Couch, James R; Deddens, James A

2017-08-01

The US Occupational Safety and Health Administration (OSHA) recently proposed a permissible exposure limit of 0.2 µg/m 3 for beryllium, based partly on extrapolated estimates of lung cancer risk from a pooled occupational cohort. The purpose of the present analysis was to evaluate whether cohort members exposed at lower levels to mainly insoluble forms of beryllium exhibit increased risk of lung cancer. We conducted Cox proportional hazards regression analyses among 75 lung cancer cases in age-based risk sets within two lower exposure plants in the pooled cohort followed from 1940 to 2005. We used categorical and power models to evaluate exposure-response patterns for mean and cumulative beryllium exposures in the two-plant cohort, comparing findings with the full pooled cohort. We also evaluated the distribution of exposure-years in each cohort by solubility class (soluble, insoluble and mixed). 98% of workers in the two-plant cohort were hired between 1955 and 1969. The mean beryllium exposure averaged 1.3 µg/m 3 and the predominant form was insoluble. Adjusting for confounders, we observed a monotonic increase in lung cancer mortality across exposure categories in the two-plant cohort. The exposure-response coefficients (per unit ln exposure) were 0.270 (p=0.061) for mean exposure and 0.170 (p=0.033) for cumulative exposure, compared with 0.155 and 0.094 (respectively) in the full cohort. The low-exposure levels at these two plants and the predominance of insoluble beryllium suggest that the overall pooled cohort findings on which OSHA's lung cancer risk assessment is based are relevant for current workers exposed to any form of beryllium. © 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.

Effects of low-level blast exposure on the nervous system: Is there really a controversy?

Directory of Open Access Journals (Sweden)

Gregory A Elder

2014-12-01

Full Text Available High-pressure blast waves can cause extensive CNS injury in humans. However, in combat settings such as Iraq and Afghanistan, lower level exposures associated with mild TBI (mTBI or subclinical exposure have been much more common. Yet controversy exists concerning what traits can be attributed to low-level blast, in large part due to the difficulty of distinguishing blast-related mTBI from post-traumatic stress disorder (PTSD. We describe how TBI is defined in humans and the problems posed in using current definitions to recognize blast-related mTBI. We next consider the problem of applying definitions of human mTBI to animal models, in particular that TBI severity in humans is defined in relation to alteration of consciousness at the time of injury, which typically cannot be assessed in animals. However, based on outcome assessments a condition of low-level blast exposure can be defined in animals that likely approximates human mTBI or subclinical exposure. We review blast injury modeling in animals noting that inconsistencies in experimental approach have contributed to uncertainty over the effects of low-level blast. Yet animal studies show that low-level blast pressure waves are transmitted to the brain. In brain low-level blast exposures cause behavioral, biochemical, pathological and physiological effects on the nervous system including the induction of PTSD-related behavioral traits in the absence of a psychological stressor. We review the relationship of blast exposure to chronic neurodegenerative diseases noting the paradoxical lowering of Abeta by blast, which along with other observations suggest that blast-related TBI is pathophysiologically distinct from non-blast TBI. Human neuroimaging studies show that blast-related mTBI is associated with a variety of chronic effects that are unlikely to be explained by co-morbid PTSD. We conclude that abundant evidence supports low-level blast as having long-term effects on the nervous system.

In situ exposure to non-directional beacons for air traffic control.

Science.gov (United States)

Joseph, Wout; Goeminne, Francis; Vermeeren, Günter; Verloock, Leen; Martens, Luc

2012-04-01

In situ electromagnetic field exposure of workers and the general public due to non-directional beacons (NDB) for air traffic control is assessed and characterized. For occupational exposure, the maximal measured electric field value is 881.6 V/m and the maximal magnetic field value is 9.1 A/m. The maximum electric fields exceed the International Commission on Non-Ionizing Radiation Protection (ICNIRP) reference levels at all seven NDB sites, and the magnetic fields at two of the seven NDB sites (occupational exposure). Recommendations and compliance distances for workers and the general public are provided. © 2012 Wiley Periodicals, Inc.

Low level methylmercury exposure affects neuropsychological function in adults

Directory of Open Access Journals (Sweden)

Platt Illeane

2003-06-01

Full Text Available Abstract Background The neurotoxic effects of methylmercury (MeHg have been demonstrated in both human and animal studies. Both adult and fetal brains are susceptible to the effects of MeHg toxicity. However, the specific effects of adult exposures have been less well-documented than those of children with prenatal exposures. This is largely because few studies of MeHg exposures in adults have used sensitive neurological endpoints. The present study reports on the results of neuropsychological testing and hair mercury concentrations in adults (>17 yrs living in fishing communities of Baixada Cuiabana (Mato Grosso in the Pantanal region of Brazil. Methods A cross-sectional study was conducted in six villages on the Cuiaba River. Participants included 129 men and women older than 17 years of age. They were randomly selected in proportion to the age range and number of inhabitants in each village. Questionnaire information was collected on demographic variables, including education, occupation, and residence history. Mercury exposure was determined by analysis of hair using flameless atomic absorption spectrophotometry. The neurocognitive screening battery included tests from the Wechsler Memory Scale and the Wechsler Adult Intelligence Scale, Concentrated Attention Test of the Toulouse-Pierron Factorial Battery, the Manual Ability Subtests of the Tests of Mechanical Ability, and the Profile of Mood States. Results Mercury exposures in this population were associated with fish consumption. The hair mercury concentration in the 129 subjects ranged from 0.56 to 13.6 μg/g; the mean concentration was 4.2 ± 2.4 micrograms/g and the median was 3.7 μg/g. Hair mercury levels were associated with detectable alterations in performance on tests of fine motor speed and dexterity, and concentration. Some aspects of verbal learning and memory were also disrupted by mercury exposure. The magnitude of the effects increased with hair mercury concentration

Mapping very low level occupational exposure in medical imaging: A useful tool in risk communication and decision making

Energy Technology Data Exchange (ETDEWEB)

Covens, P., E-mail: pcovens@vub.ac.be [Health Physics Department, Vrije Universiteit Brussel and UZ Brussel, Laarbeeklaan 103, 1090 Brussels (Belgium); Beeldvorming en Fysische Wetenschappen (BEFY), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels (Belgium); Berus, D., E-mail: dberus@vub.ac.be [Health Physics Department, Vrije Universiteit Brussel and UZ Brussel, Laarbeeklaan 103, 1090 Brussels (Belgium); Mey, J. de, E-mail: Johan.DeMey@uzbrussel.be [Department of Radiology, UZ Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium); Beeldvorming en Fysische Wetenschappen (BEFY), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels (Belgium); Buls, N., E-mail: Nico.Buls@uzbrussel.be [Department of Radiology, UZ Brussel, Laarbeeklaan 101, 1090 Brussels (Belgium); Beeldvorming en Fysische Wetenschappen (BEFY), Vrije Universiteit Brussel, Laarbeeklaan 103, 1090 Brussels (Belgium)

2012-09-15

Objectives: The use of ionising radiation in medical imaging is accompanied with occupational exposure which should be limited by optimised room design and safety instructions. These measures can however not prevent that workers are exposed to instantaneous dose rates, e.g. the residual exposure through shielding or the exposure of discharged nuclear medicine patients. The latter elements are often questioned by workers and detailed assessment should give more information about the impact on the individual radiation dose. Methods: Cumulated radiation exposure was measured in a university hospital during a period of 6 months by means of thermoluminescent dosimeters. Radiation exposure was measured at background locations and at locations where enhanced exposure levels are expected but where the impact on the individual exposure is unclear. Results: The results show a normal distribution of the cumulated background radiation level. No enhanced cumulated radiation exposure which significantly differs from this background level could be found during the operation of intra-oral apparatus, during ultrasonography procedures among nuclear medicine patients and at operator consoles of most CT-rooms. Conclusions: This 6 months survey offers useful information about occupational low level exposure in medical imaging and the findings can be useful in both risk communication and decision making.

Mapping very low level occupational exposure in medical imaging: A useful tool in risk communication and decision making

International Nuclear Information System (INIS)

Covens, P.; Berus, D.; Mey, J. de; Buls, N.

2012-01-01

Objectives: The use of ionising radiation in medical imaging is accompanied with occupational exposure which should be limited by optimised room design and safety instructions. These measures can however not prevent that workers are exposed to instantaneous dose rates, e.g. the residual exposure through shielding or the exposure of discharged nuclear medicine patients. The latter elements are often questioned by workers and detailed assessment should give more information about the impact on the individual radiation dose. Methods: Cumulated radiation exposure was measured in a university hospital during a period of 6 months by means of thermoluminescent dosimeters. Radiation exposure was measured at background locations and at locations where enhanced exposure levels are expected but where the impact on the individual exposure is unclear. Results: The results show a normal distribution of the cumulated background radiation level. No enhanced cumulated radiation exposure which significantly differs from this background level could be found during the operation of intra-oral apparatus, during ultrasonography procedures among nuclear medicine patients and at operator consoles of most CT-rooms. Conclusions: This 6 months survey offers useful information about occupational low level exposure in medical imaging and the findings can be useful in both risk communication and decision making

Outdoor radiofrequency radiation levels in the West Bank-palestine

International Nuclear Information System (INIS)

Lahham, A.; Hammash, A.

2012-01-01

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 . (authors)

Impact of 900 MHz electromagnetic field exposure on main male reproductive hormone levels: a Rattus norvegicus model

Science.gov (United States)

Sepehrimanesh, Masood; Saeb, Mehdi; Nazifi, Saeed; Kazemipour, Nasrin; Jelodar, Gholamali; Saeb, Saeedeh

2014-09-01

This work analyzes the effects of radiofrequency-electromagnetic field (RF-EMF) exposure on the reproductive system of male rats, assessed by measuring circulating levels of FSH, LH, inhibin B, activin B, prolactin, and testosterone. Twenty adult male Sprague-Dawley rats (180 ± 10 g) were exposed to 900 MHz RF-EMF in four equal separated groups. The duration of exposure was 1, 2, and 4 h/day over a period of 30 days and sham-exposed animals were kept under the same environmental conditions as the exposed group except with no RF-EMF exposure. Before the exposure, at 15 and 30 days of exposure, determination of the abovementioned hormone levels was performed using ELISA. At the end of the experiment, FSH and LH values of the long time exposure (LTE) group were significantly higher than the sham-exposed group ( p reproductive hormone levels are disturbed as a result of RF-EMF exposure and it may possibly affect reproductive functions. However, testosterone and inhibin B concentrations as a fertility marker and spermatogenesis were decreased significantly.

Tributyltin exposure alters cytokine levels in mouse serum.

Science.gov (United States)

Lawrence, Shanieek; Pellom, Samuel T; Shanker, Anil; Whalen, Margaret M

2016-11-01

Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, keratinocyte chemoattractant (KC), macrophage inflammatory protein 1β (MIP), MIP2 and regulated on activation normal T-cell-expressed and secreted (RANTES) was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40 and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in the serum of mice exposed to TBT for less than 24 h. Levels of IL1β, IL-12 βp40, IL-5 and IL-15 were also modulated in mouse serum, depending on the specific experiment and exposure level. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines.

Hexachlorobenzene sources, levels and human exposure in the environment of China

NARCIS (Netherlands)

Wang, G.; Lu, Y.L.; Han, Jingyi; Luo, W.; Shi, Y.J.; Wang, T.Y.; Sun, Y.M.

2010-01-01

This article summarizes the published scientific data on sources, levels and human exposure of hexachlorobenzene (HCB) in China. Potential sources of unintended HCB emission were assessed by production information, emission factors and environmental policies. HCB was observed in various

Seasonal variations of radon and the radiation exposure levels in Nerja cave, Spain

International Nuclear Information System (INIS)

Duenas, C.; Fernandez, M.C.; Canete, S.; Perez, M.; Gordo, E.

2011-01-01

222 Rn concentrations in the air in Nerja cave (Spain) (3 o 52'35''W 36 o 43'50''N) were measured by continuous monitoring using Alpha-Guard, Genitron instrument equipment. The 222 Rn measurements were carried out for a complete annual cycle in the different halls: Vestibule hall from July 2003 to June 2004, Ballet hall from July 2004 to June 2005 and Mirador hall from July 2005 to June 2006. Starting from the entrance of the cave we successively find the Vestibule hall, the Ballet hall and the Mirador hall. The range of 222 Rn levels were of 8-627 Bq m -3 for the Vestibule hall, 28-575 Bq m -3 for the Ballet hall and 38-578 Bq m -3 for the Mirador. The aim of this study was to detect seasonal variation patterns of 222 Rn concentrations. The seasonal variations of 222 Rn concentrations are discussed in relation to various meteorological factors measured inside and outside the cave. The radiation exposure levels for workers and tourists with different equilibrium factors have been evaluated. The radiation exposure levels for workers and tourists only represent a low percentage of the exposure guides for the general population. - Highlights: → The aim of the study was to detect seasonal variation of 222 Rn concentrations. → 222 Rn concentrations in the air-cave were measured by continuous monitoring. → The 222 Rn measurements were carried out in the different halls of the cave. → The radiation exposure levels for workers and tourists have been evaluated.

Exposure due to radon in homes - an IAEA perspective

International Nuclear Information System (INIS)

Navratilova-Rovenska, K.; Boal, T.; Colgan, T.

2014-01-01

The results of miner and residential epidemiology studies provide statistically strong evidence of harmful effects of exposure due to radon and its progeny. With the publication of the fifth edition of the International Basic Safety Standards, of the World Health Organizations Handbook on Indoor Radon and new ICRP statement on radon, there is increased interest from the public health and radiation protection authorities on controlling exposure due to radon and its progeny.The IAEA Safety Requirements publication 'Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards' sets out requirements on governments for control of existing exposure situations, which includes exposure due to radon. The types of situation that are included in the scope of existing exposure situations include exposure in workplaces for which the exposure due to radon is not required by or directly related to the work and for which annual average activity concentrations due to 222 Rn must not exceed a maximum reference level of 1000 Bq/m 3 annual activity concentration, as well as exposure in dwellings and in other buildings with high occupancy factors for members of the public for which the reference level must not exceed a maximum value of 300 Bq/m 3 . These requirements include: collecting data on the activity concentrations of radon in dwellings and other buildings with high occupancy by the public; providing information on exposure due to radon and the associated health risks; and if necessary, to develop an action plan for controlling public exposure to radon. The IAEA has developed a Safety Guide to provide guidance on developing the radon action plan: 'Protection of the Public against Exposure Indoors due to Radon and Other Natural Sources of Radiation'. This presentation will summarize the information on the assistance that the IAEA is currently providing to IAEA Member States to develop radon action plans. These activities include

Potential exposures and health effects from spent fuel transportation

International Nuclear Information System (INIS)

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

1986-01-01

The radiation exposures and consequent health effects associated with normal operations and accidents during transportation of spent fuel have been analyzed and evaluated. This study was performed for the U.S. Department of Energy (DOE) as contributory data for response to specific public inquires regarding the Draft Environmental Assessments issued by DOE in 1984. Large quantities of spent fuel from power reactors will be shipped by truck and/or rail from the site of generation or temporary storage to nuclear waste repositories. This transportation activity has the potential for increasing radiation exposures and risks above normal background levels in the vicinity of the transportation route. For normal, accident-free transport of spent fuel, radiation exposures arise from both gamma and neutron sources within the spent fuel cask. U.S. regulations limit the radiation dose equivalent rate to 10 millirem per hour at any point 2 meters from the outer lateral surfaces of the transport vehicle. Computer program PATHRAE-T was developed and employed to determine the total, combined dose field. PATHRAE-T was used to estimate the maximum individual doses from rail cask accidents. The maximum individual exposure, primarily due to inhalation, is about 10 rem and occurs about 70 meters downwind. Ground deposited nuclides account for 99 percent of the population dose. The maximum population dose accident could result in about 22 latent health effects for the urban population. The same case rail cask accidents were also evaluated for a maximum water pathway contamination scenario. The nuclide contaminated plume was assumed to be transported over a large reservoir used for domestic and agricultural water. This accident could result in a 63,000 person-rem dose causing about 13 latent health effects in the absence of any natural and industrial processes for nuclide removal from the water

The Red Sea during the Last Glacial Maximum: implications for sea level reconstructions

Science.gov (United States)

Gildor, H.; Biton, E.; Peltier, W. R.

2006-12-01

The Red Sea (RS) is a semi-enclosed basin connected to the Indian Ocean via a narrow and shallow strait, and surrounded by arid areas which exhibits high sensitivity to atmospheric changes and sea level reduction. We have used the MIT GCM to investigate the changes in the hydrography and circulation in the RS in response to reduced sea level, variability in the Indian monsoons, and changes in atmospheric temperature and humidity that occurred during the Last Glacial Maximum (LGM). The model results show high sensitivity to sea level reduction especially in the salinity field (increasing with the reduction in sea level) together with a mild atmospheric impact. Sea level reduction decreases the stratification, increases subsurface temperatures, and alters the circulation pattern at the Strait of Bab el Mandab, which experiences a transition from submaximal flow to maximal flow. The reduction in sea level at LGM alters the location of deep water formation which shifts to an open sea convective site in the northern part of the RS compared to present day situation in which deep water is formed from the Gulf of Suez outflow. Our main result based on both the GCM and on a simple hydraulic control model which takes into account mixing process at the Strait of Bab El Mandeb, is that sea level was reduced by only ~100 m in the Bab El Mandeb region during the LGM, i.e. the water depth at the Hanish sill (the shallowest part in the Strait Bab el Mandab) was around 34 m. This result agrees with the recent reconstruction of the LGM low stand of the sea in this region based upon the ICE-5G (VM2) model of Peltier (2004).

Maximum flood hazard assessment for OPG's deep geologic repository for low and intermediate level waste

International Nuclear Information System (INIS)

Nimmrichter, P.; McClintock, J.; Peng, J.; Leung, H.

2011-01-01

Ontario Power Generation (OPG) has entered a process to seek Environmental Assessment and licensing approvals to construct a Deep Geologic Repository (DGR) for Low and Intermediate Level Radioactive Waste (L&ILW) near the existing Western Waste Management Facility (WWMF) at the Bruce nuclear site in the Municipality of Kincardine, Ontario. In support of the design of the proposed DGR project, maximum flood stages were estimated for potential flood hazard risks associated with coastal, riverine and direct precipitation flooding. The estimation of lake/coastal flooding for the Bruce nuclear site considered potential extreme water levels in Lake Huron, storm surge and seiche, wind waves, and tsunamis. The riverine flood hazard assessment considered the Probable Maximum Flood (PMF) within the local watersheds, and within local drainage areas that will be directly impacted by the site development. A series of hydraulic models were developed, based on DGR project site grading and ditching, to assess the impact of a Probable Maximum Precipitation (PMP) occurring directly at the DGR site. Overall, this flood assessment concluded there is no potential for lake or riverine based flooding and the DGR area is not affected by tsunamis. However, it was also concluded from the results of this analysis that the PMF in proximity to the critical DGR operational areas and infrastructure would be higher than the proposed elevation of the entrance to the underground works. This paper provides an overview of the assessment of potential flood hazard risks associated with coastal, riverine and direct precipitation flooding that was completed for the DGR development. (author)

Effective exposure level and diagnostic performance in endodontic radiography

International Nuclear Information System (INIS)

Okano, T.; Wiebe, J.D.; Webber, R.L.; Wagner, R.F.

1983-01-01

Image quality is limited by the information capacity of the image-forming system and can be computed from three parameters: contrast, resolution, and noise. These parameters can be combined to yield a single measure which determines the maximum amount of information obtainable from any x-ray system and is called the noise-equivalent number of quanta (NEQ) per unit area. The effects of image quality, expressed as noise-equivalent number of quanta (NEQ) per unit area, on the radiographic performance by dentists reading the position of an endodontic file in a root canal were studied. Three different speed films were used in conjunction with a fixed screen. Components of variance associated with the position of the tooth apex and the tip of an endodontic file in a root canal were compared for the effect of different NEQs and observers. Results show that the standard deviation in locating a file tip and tooth apex may be a linear function of log NEQ. These findings indicate that a significant reduction in exposure would have a relatively small effect on the precision of endodontic distance measurements

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

International Nuclear Information System (INIS)

Adu-Kumi, S.

2011-01-01

�-HCH which is a known environmental estrogen, was predominant contaminant measured (geometric mean concentrations 4.18 ng g -1 lipid wt. and 4.35 ng g -1 lipid wt. for pooled and individual samples respectively). The levels of Lindane, α-HCH and β-HCH in edible fish (catfish and tilapia) sourced from Lake Bosumtwi and the Weija Lake, were concurrently investigated using HRGC/HRMS. Concentrations of HCHs were found to be generally low (mainly limits of detection) probably reflecting the historical use of Lindane and technical HCH mixtures. Catfish sourced from Lake Volta (purchased from the Madina market) however contained appreciable amounts of Lindane (average concentration of 0.72 ng g -1 lipid wt). Measured values are lower than the maximum acceptable limit for human consumption established by the FAO/WHO (FAO/WHO, 1986). Hence there is no potential health risk from HCHs (Lindane, α-HCH and β-HCH) in fish for the general population of Ghana. Level III and level IV fugacity models were successfully applied to investigate the environmental fate of Lindane in the compartments of air, water, sediment, soil and biota (fish). Model estimates showed that air, water, soil and fish constitute important exposure pathways of Lindane for the general population of Ghana. The estimated total amount of Lindane accumulated in all media at steady-state was 136 tonnes, the soil compartment accounting for ore than 97% of the total accumulation. Time trends in concentration and fluxes simulated in for the period 1959-2020 predicted that less than 1% of the 2002 concentration levels of Lindane in air, water and soil, respectively, will be left in 2020. Finally, health risks associated with the exposure of the general population of Ghana to Lindane via the pathways of air, water, soil, food (or diet) were characterized using the combined field measurements and results of the multi-media environmental fate modelling. Diet (mainly vegetables), soil and to a lesser extent water constituted

Low levels of vitamin D poorly responsive to daylight exposure in patients with therapy-resistant schizophrenia.

Science.gov (United States)

Bogers, Jan P.A.M.; Bostoen, Tijmen; Broekman, Theo G.

2016-01-01

Low vitamin D levels are associated with schizophrenia, but the possible association between vitamin D levels and illness severity or duration of exposure to daylight has barely been investigated. To compare vitamin D levels in therapy-refractory severely ill schizophrenia patients and members of staff. To investigate the influence of daylight exposure on vitamin D levels in patients. Vitamin D was measured in patients with therapy-resistant schizophrenia in April, after the winter, and in patients and staff members in June, after an exceptionally sunny spring. Vitamin D levels in April and June were compared in patients, and levels in June were compared in patients and staff. The influence of daylight was taken into account by comparing the time patients spent outdoors during the day with the recommended minimum time for adequate vitamin D synthesis, and by comparing time spent outdoors in patients and staff. Patients had high rates of vitamin D deficiency (79-90%) and lower levels of vitamin D than staff members (p vitamin D levels did not normalize, despite the considerably longer than recommended exposure of the skin to daylight (p vitamin D deficiency of therapy-resistant schizophrenia patients is pronounced and cannot be explained by differences in skin pigmentation or by an inactive, indoor lifestyle on the ward. Even theoretically sufficient exposure of the patients to daylight did not ameliorate the low vitamin D levels. While vitamin D deficiency probably plays a role in somatic health problems, it may also play a role in schizophrenia. Interestingly, exposure to daylight during an unusually sunny spring was not sufficient to correct the vitamin D deficiency seen in the patients. This emphasizes the need to measure and correct vitamin D levels in these patients.

Excitation of high energy levels under laser exposure of suspensions of nanoparticles in liquids

Energy Technology Data Exchange (ETDEWEB)

Shafeev, G.A. [Wave Research Center of A.M. Prokhorov General Physics Institute, 38, Vavilov Street, 119991 Moscow (Russian Federation)], E-mail: shafeev@kapella.gpi.ru; Simakin, A.V. [Wave Research Center of A.M. Prokhorov General Physics Institute, 38, Vavilov Street, 119991 Moscow (Russian Federation); Bozon-Verduraz, F. [ITODYS, UMR CNRS 7086, Universite Paris 7-Denis Diderot, 2, place Jussieu, 75251 Paris cedex 05 (France); Robert, M. [Laboratoire d' Electrochimie Moleculaire, UMR CNRS 7591, Universite Paris 7 Denis Diderot, 2, place Jussieu, 75251 Paris cedex 05 (France)

2007-12-15

Laser exposure of suspensions of nanoparticles in liquids leads to excitation of high energy levels in both liquid and nanoparticle material. The emission spectrum of the colloidal solution under exposure of a suspension metallic nanoparticles in water to radiation of a Nd:YAG laser of a picosecond range of pulse duration is discussed. Excitation of nuclear energy levels and neutron release is experimentally studied on the model system of transmutation of Hg into Au that occurs under exposure of Hg nanodrops suspended in D{sub 2}O. The proposed mechanism involves: (i) emission of X-ray photons by Hg nanoparticles upon laser exposure, leading to neutron release from D{sub 2}O, (ii) initiation of Hg {yields} Au transmutation by the capture of neutrons. The effect of transmutation is more pronounced using {sup 196}Hg isotope instead of Hg of natural isotope composition. The influence of laser pulse duration on the degree of transmutation (from fs through ns range) is discussed.

The application of a Grey Markov Model to forecasting annual maximum water levels at hydrological stations

Science.gov (United States)

Dong, Sheng; Chi, Kun; Zhang, Qiyi; Zhang, Xiangdong

2012-03-01

Compared with traditional real-time forecasting, this paper proposes a Grey Markov Model (GMM) to forecast the maximum water levels at hydrological stations in the estuary area. The GMM combines the Grey System and Markov theory into a higher precision model. The GMM takes advantage of the Grey System to predict the trend values and uses the Markov theory to forecast fluctuation values, and thus gives forecast results involving two aspects of information. The procedure for forecasting annul maximum water levels with the GMM contains five main steps: 1) establish the GM (1, 1) model based on the data series; 2) estimate the trend values; 3) establish a Markov Model based on relative error series; 4) modify the relative errors caused in step 2, and then obtain the relative errors of the second order estimation; 5) compare the results with measured data and estimate the accuracy. The historical water level records (from 1960 to 1992) at Yuqiao Hydrological Station in the estuary area of the Haihe River near Tianjin, China are utilized to calibrate and verify the proposed model according to the above steps. Every 25 years' data are regarded as a hydro-sequence. Eight groups of simulated results show reasonable agreement between the predicted values and the measured data. The GMM is also applied to the 10 other hydrological stations in the same estuary. The forecast results for all of the hydrological stations are good or acceptable. The feasibility and effectiveness of this new forecasting model have been proved in this paper.

PUBLIC EXPOSURE TO MULTIPLE RF SOURCES IN GHANA.

Science.gov (United States)

Deatanyah, P; Abavare, E K K; Menyeh, A; Amoako, J K

2018-03-16

This paper describes an effort to respond to the suggestion in World Health Organization (WHO) research agenda to better quantify potential exposure levels from a range of radiofrequency (RF) sources at 200 public access locations in Ghana. Wide-band measurements were performed-with a spectrum analyser and a log-periodic antenna using three-point spatial averaging method. The overall results represented a maximum of 0.19% of the ICNIRP reference levels for public exposure. These results were generally lower than found in some previous but were 58% (2.0 dB) greater, than found in similar work conducted in the USA. Major contributing sources of RF fields were identified to be FM broadcast and mobile base station sites. Three locations with the greatest measured RF fields could represent potential areas for epidemiological studies.

Background paper for regulations related to the exposure of uranium mine and mill workers

International Nuclear Information System (INIS)

1978-01-01

The Atomic Energy Control Board is modifying the Atomic Energy Control Regulations to include a maximum permissible exposure to radon daughters for uranium mine and mill workers. In January 1976, after consultation with the uranium producers, union, and government regulatory bodies, the AECB issued a directive endorsing a maximum permissible annual occupational exposure to radon daughters of 4 Working Level Months (WLM). This exposure limit was an interim guideline to be applied for at least one year. The Board staff and members of the Mine Safety Advisory Committee have examined available evidence on the excess risk of lung cancer owing to exposure to radon daughters since then, and have assessed the arguments for both raising and lowering the exposure limit. The evidence is still not conclusive, and further studies, especially epidemiological ones, are needed. Nevertheless, the Board considers that the interim guideline is acceptable in the light of the present state of knowledge and that it should be incorporated into the regulations. This document explains why the Board has made this decision and discusses a number of related issues

External and internal exposure to natural radiations inside ancient Egyptian tombs in Saqqara

Energy Technology Data Exchange (ETDEWEB)

Abo-Elmagd, M [National Institute for Standard, Radiation Measurements Department, P.O. Box 136 Giza code no. 12211 (Egypt); Metwally, S M [Faculty of Science, Department of Physics, Ain Shams University, P.O. Box 11566, Cairo (Egypt); Elmongy, S A [Atomic Energy Authority, Nuclear Safety, Cairo (Egypt); Salama, E [Faculty of Science, Department of Physics, Ain Shams University, P.O. Box 11566, Cairo (Egypt); El-Fiki, S A [Faculty of Science, Department of Physics, Ain Shams University, P.O. Box 11566, Cairo (Egypt)

2006-02-15

Some ancient Egyptian tombs in Saqqara are closed for visit to undergo fixation processes. The workers inside these tombs exposed to natural radiations from natural Gamma emitters (external exposure) and inhale unknown radon doses (internal exposure) for long periods. The external exposure in all studied tombs is lower than the maximum recommended action level. The internal exposure in terms of annual effective dose in the south tomb is equal to 28.83mSv/year which highly exceed the recommended level (3-10mSv/year). In this tomb, the external exposure is equal to 21.43{mu}Sv/year. This reflects the hazards of radon over the other natural radiations in the closed area. Among the workers inside the studied tombs, the expected morality is equal to 0.0033%, 0.0199% and 0.0724% for the south entrance of Zoser pyramid, the Serapeum tomb, and the south tomb respectively. ctively.

External and internal exposure to natural radiations inside ancient Egyptian tombs in Saqqara

International Nuclear Information System (INIS)

Abo-Elmagd, M.; Metwally, S.M.; Elmongy, S.A.; Salama, E.; El-Fiki, S.A.

2006-01-01

Some ancient Egyptian tombs in Saqqara are closed for visit to undergo fixation processes. The workers inside these tombs exposed to natural radiations from natural Gamma emitters (external exposure) and inhale unknown radon doses (internal exposure) for long periods. The external exposure in all studied tombs is lower than the maximum recommended action level. The internal exposure in terms of annual effective dose in the south tomb is equal to 28.83mSv/year which highly exceed the recommended level (3-10mSv/year). In this tomb, the external exposure is equal to 21.43μSv/year. This reflects the hazards of radon over the other natural radiations in the closed area. Among the workers inside the studied tombs, the expected morality is equal to 0.0033%, 0.0199% and 0.0724% for the south entrance of Zoser pyramid, the Serapeum tomb, and the south tomb respectively. ctively

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

Science.gov (United States)

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

2013-01-01

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

Does apartment's distance to an in-built transformer room predict magnetic field exposure levels?

Science.gov (United States)

Huss, Anke; Goris, Kelly; Vermeulen, Roel; Kromhout, Hans

2013-01-01

It has been shown that magnetic field exposure in apartments located directly on top or adjacent to transformer rooms is higher compared with exposure in apartments located further away from the transformer rooms. It is unclear whether this also translates into exposure contrast among individuals living in these apartments. We performed spot measurements of magnetic fields in 35 apartments in 14 apartment buildings with an in-built transformer and additionally performed 24-h personal measurements in a subsample of 24 individuals. Apartments placed directly on top of or adjacent to a transformer room had on average exposures of 0.42 μT, apartments on the second floor on top of a transformer room, or sharing a corner or edge with the transformer room had 0.11 μT, and apartments located further away from the transformer room had levels of 0.06 μT. Personal exposure levels were approximately a factor 2 lower compared with apartment averages, but still showed exposure contrasts, but only for those individuals who live in the apartments directly on top or adjacent to a transformer room compared with those living further away, with 0.23 versus 0.06 μT for personal exposure when indoors, respectively. A classification of individuals into 'high' and 'low' exposed based on the location of their apartment within a building with an in-built transformer is possible and could be applied in future epidemiological studies.

Sex specific response in cholesterol level in zebrafish (Danio rerio) after long-term exposure of difenoconazole

International Nuclear Information System (INIS)

Mu, Xiyan; Wang, Kai; Chai, Tingting; Zhu, Lizhen; Yang, Yang; Zhang, Jie; Pang, Sen; Wang, Chengju; Li, Xuefeng

2015-01-01

Difenoconazole is a widely used triazole fungicide, its extensive application may potentially cause toxic effects on non-target organisms. To investigate the effect of difenoconazole on cholesterol content and related mechanism, adult zebrafish were exposed to environmental related dosage (0.1, 10 and 500 μg/L) difenoconazole. The body weight and hepatic total cholesterol (TCHO) level was tested at 7, 15 and 30 days post exposure (dpe). The expressions of eight cholesterol synthesis genes and one cholesterol metabolism gene were assessed via Quantitative PCR method. The significant decrease of TCHO level in male zebrafish liver was observed at 15 and 30 dpe, which was accompanied by apparent hepatic cholesterol-genesis genes expression decline. In comparison with males, female zebrafish showed different transcription modification of tested genes, and the cholesterol content maintain normal level during the whole exposure. - Highlights: • Difenoconazle could reduce TCHO level in male zebrafish liver. • Difenoconazole could inhibit sterol-genesis genes expression in male zebrafish. • Female zebrafish didn't show obvious change of TCHO level after exposure. • Difenoconazole could inhibit body weight of both male and female zebrafish. - Difenoconazle could reduce cholesterol level and sterol-genesis genes expression in male zebrafish. While female zebrafish showed no obvious cholesterol content change during exposure

Blood morphology and the levels of selected cytokines related to hematopoiesis in occupational short-term exposure to lead

International Nuclear Information System (INIS)

Dobrakowski, Michał; Boroń, Marta; Czuba, Zenon P.; Birkner, Ewa; Chwalba, Artur; Hudziec, Edyta; Kasperczyk, Sławomir

2016-01-01

The aim of the study was to investigate the influence of a short-term exposure to lead on the blood morphology and the levels of selected cytokines related to hematopoiesis in occupationally exposed workers. The study population included 37 males occupationally exposed to lead for 36 to 44 days. Their blood lead level raised from 10.7 ± 7.67 μg/dl at baseline to the level of 49.1 ± 14.1 μg/dl at the end of the study. The level of hemoglobin and values of MCH and MCHC were decreased due to a short-term exposure to lead by 2%, 2%, and 1%, respectively. The counts of WBC, LYM, and MXD increased significantly by 5%, 7%, and 35%. Similarly, the count of PLT increased by 7%, while PDW, MPV, and P-LCR decreased by 6%, 3%, and 9%, respectively. The levels of IL-7, G-CSF, HGF, PDGF AB/BB, SCF, and PECAM-1, decreased significantly by 30%, 33%, 8%, 30%, 25%, and 20%, respectively. A short-term occupational exposure to lead results in a decreased hemoglobin level and increased counts of WBC and PLT. Changes in counts and proportions of different types of leukocytes and decreased values of PLT indices, such as PDW, MPV, and P-LCR, due to the subacute lead-exposure may be associated with lead-induced decreased levels of cytokines related to hematopoiesis, including SCF, G-CSF, IL-7, and PDGF. - Highlights: • Subacute exposure to lead results in a decreased hemoglobin level. • Subacute exposure to lead results in increased counts of WBC and PLT. • Subacute exposure to lead decreases the levels of SCF, G-CSF, IL-7, and PDGF.

Blood morphology and the levels of selected cytokines related to hematopoiesis in occupational short-term exposure to lead

Energy Technology Data Exchange (ETDEWEB)

Dobrakowski, Michał, E-mail: michal.dobrakowski@poczta.fm [Department of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland); Boroń, Marta [Institute of Occupational Medicine and Environmental Health in Sosnowiec, ul. Kościelna 13, 41-200 Sosnowiec (Poland); Czuba, Zenon P. [Department of Microbiology and Immunology, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland); Birkner, Ewa [Department of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland); Chwalba, Artur [SP ZOZ Municipal Hospital, Department of Internal Medicine, ul. Strzelców Bytomskich 11, 41-500 Chorzów (Poland); Hudziec, Edyta; Kasperczyk, Sławomir [Department of Biochemistry, School of Medicine with the Division of Dentistry, Medical University of Silesia, ul. Jordana 19, 41-808 Zabrze (Poland)

2016-08-15

The aim of the study was to investigate the influence of a short-term exposure to lead on the blood morphology and the levels of selected cytokines related to hematopoiesis in occupationally exposed workers. The study population included 37 males occupationally exposed to lead for 36 to 44 days. Their blood lead level raised from 10.7 ± 7.67 μg/dl at baseline to the level of 49.1 ± 14.1 μg/dl at the end of the study. The level of hemoglobin and values of MCH and MCHC were decreased due to a short-term exposure to lead by 2%, 2%, and 1%, respectively. The counts of WBC, LYM, and MXD increased significantly by 5%, 7%, and 35%. Similarly, the count of PLT increased by 7%, while PDW, MPV, and P-LCR decreased by 6%, 3%, and 9%, respectively. The levels of IL-7, G-CSF, HGF, PDGF AB/BB, SCF, and PECAM-1, decreased significantly by 30%, 33%, 8%, 30%, 25%, and 20%, respectively. A short-term occupational exposure to lead results in a decreased hemoglobin level and increased counts of WBC and PLT. Changes in counts and proportions of different types of leukocytes and decreased values of PLT indices, such as PDW, MPV, and P-LCR, due to the subacute lead-exposure may be associated with lead-induced decreased levels of cytokines related to hematopoiesis, including SCF, G-CSF, IL-7, and PDGF. - Highlights: • Subacute exposure to lead results in a decreased hemoglobin level. • Subacute exposure to lead results in increased counts of WBC and PLT. • Subacute exposure to lead decreases the levels of SCF, G-CSF, IL-7, and PDGF.

Mercury exposure may suppress baseline corticosterone levels in juvenile birds.

Science.gov (United States)

Herring, Garth; Ackerman, Joshua T; Herzog, Mark P

2012-06-05

Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury concentrations in down feathers of recently hatched (feathers (decreasing by 45% across the range of observed mercury concentrations) while accounting for stronger positive correlations between corticosterone concentrations and colony nest abundance and date. These results indicate that chronic mercury exposure may suppress baseline corticosterone concentrations in tern chicks and suggests that a juvenile bird's ability to respond to stress may be reduced via the downregulation of the HPA axis.

Spatiotemporal modeling of ozone levels in Quebec (Canada): a comparison of kriging, land-use regression (LUR), and combined Bayesian maximum entropy-LUR approaches.

Science.gov (United States)

Adam-Poupart, Ariane; Brand, Allan; Fournier, Michel; Jerrett, Michael; Smargiassi, Audrey

2014-09-01

Ambient air ozone (O3) is a pulmonary irritant that has been associated with respiratory health effects including increased lung inflammation and permeability, airway hyperreactivity, respiratory symptoms, and decreased lung function. Estimation of O3 exposure is a complex task because the pollutant exhibits complex spatiotemporal patterns. To refine the quality of exposure estimation, various spatiotemporal methods have been developed worldwide. We sought to compare the accuracy of three spatiotemporal models to predict summer ground-level O3 in Quebec, Canada. We developed a land-use mixed-effects regression (LUR) model based on readily available data (air quality and meteorological monitoring data, road networks information, latitude), a Bayesian maximum entropy (BME) model incorporating both O3 monitoring station data and the land-use mixed model outputs (BME-LUR), and a kriging method model based only on available O3 monitoring station data (BME kriging). We performed leave-one-station-out cross-validation and visually assessed the predictive capability of each model by examining the mean temporal and spatial distributions of the average estimated errors. The BME-LUR was the best predictive model (R2 = 0.653) with the lowest root mean-square error (RMSE ;7.06 ppb), followed by the LUR model (R2 = 0.466, RMSE = 8.747) and the BME kriging model (R2 = 0.414, RMSE = 9.164). Our findings suggest that errors of estimation in the interpolation of O3 concentrations with BME can be greatly reduced by incorporating outputs from a LUR model developed with readily available data.

1-Hydroxypyrene Levels in Blood Samples of Rats After Exposure to Generator Fumes

Science.gov (United States)

Ifegwu, Clinton; Igwo-Ezikpe, Miriam N.; Anyakora, Chimezie; Osuntoki, Akinniyi; Oseni, Kafayat A.; Alao, Eragbae O.

2013-01-01

Polynuclear Aromatic Hydrocarbons (PAHs) are a major component of fuel generator fumes. Carcinogenicity of these compounds has long been established. In this study, 37 Swiss albino rats were exposed to generator fumes at varied distances for 8 hours per day for a period of 42 days and the level of 1-hydroxypyrene in their blood was evaluated. This study also tried to correlate the level of blood 1-hyroxypyrene with the distance from the source of pollution. Plasma was collected by centrifuging the whole blood sample followed by complete hydrolysis of the conjugated 1-hydroxypyrene glucuronide to yield the analyte of interest, 1-hydroxypyrene, which was achieved using beta glucuronidase. High performance liquid chromatography (HPLC) with UV detector was used to determine the 1-hydroxypyrene concentrations in the blood samples. The mobile phase was water:methanol (12:88 v/v) isocratic run at the flow rate of 1.2 mL/min with CI8 stationary phase at 250 nm. After 42 days of exposure, blood concentration level of 1-hydroxypyrene ranged from 34 μg/mL to 26.29 μg/mL depending on the distance from source of exposure. The control group had no 1-hydroxypyrene in their blood. After the period of exposure, percentage of death correlated with the distance from the source of exposure. Percentage of death ranged from 56% to zero depending on the proximity to source of pollution. PMID:24179393

Health effects of subchronic exposure to environmental levels of diesel exhaust.

Science.gov (United States)

Reed, M D; Gigliotti, A P; McDonald, J D; Seagrave, J C; Seilkop, S K; Mauderly, J L

2004-04-01

Diesel exhaust is a public health concern and contributor to both ambient and occupational air pollution. As part of a general health assessment of multiple anthropogenic source emissions conducted by the National Environmental Respiratory Center (NERC), a series of health assays was conducted on rats and mice exposed to environmentally relevant levels of diesel exhaust. This article summarizes the study design and exposures, and reports findings on several general indicators of toxicity and carcinogenic potential. Diesel exhaust was generated from a commonly used 2000 model 5.9-L, 6-cylinder turbo diesel engine operated on a variable-load heavy-duty test cycle burning national average certification fuel. Animals were exposed to clean air (control) or four dilutions of whole emissions based on particulate matter concentration (30, 100, 300, and 1000 microg/m(3)). Male and female F344 rats and A/J mice were exposed by whole-body inhalation 6 h/day, 7 days/wk, for either 1 wk or 6 mo. Exposures were characterized in detail. Effects of exposure on clinical observations, body and organ weights, serum chemistry, hematology, histopathology, bronchoalveolar lavage, and serum clotting factors were mild. Significant exposure-related effects occurring in both male and female rats included decreases in serum cholesterol and clotting Factor VII and slight increases in serum gamma-glutamyl transferase. Several other responses met screening criteria for significant exposure effects but were not consistent between genders or exposure times and were not corroborated by related parameters. Carcinogenic potential as determined by micronucleated reticulocyte counts and proliferation of adenomas in A/J mice were unaffected by 6 mo of exposure. Parallel studies demonstrated effects on cardiac function and resistance to viral infection; however, the results reported here show few and only modest health hazards from subchronic or shorter exposures to realistic concentrations of

The relationships between short-term exposure to particulate matter and mortality in Korea: impact of particulate matter exposure metrics for sub-daily exposures

International Nuclear Information System (INIS)

Son, Ji-Young; Bell, Michelle L

2013-01-01

Most studies of short-term particulate matter (PM) exposure use 24 h averages. However, other pollutants have stronger effects in shorter timeframes, which has influenced policy (e.g., ozone 8 h maximum). The selection of appropriate exposure timeframes is important for effective regulation. The US EPA identified health effects for sub-daily PM exposures as a critical research need. Unlike most areas, Seoul, Korea has hourly measurements of PM 10 , although not PM 2.5 . We investigated PM 10 and mortality (total, cardiovascular, respiratory) in Seoul (1999–2009) considering sub-daily exposures: 24 h, daytime (7 am–8 pm), morning (7–10 am), nighttime (8 pm–7 am), and 1 h daily maximum. We applied Poisson generalized linear modeling adjusting for temporal trends and meteorology. All PM 10 metrics were significantly associated with total mortality. Compared to other exposure timeframes, morning exposure had the most certain effect on total mortality (based on statistical significance). Increases of 10 μg m −3 in 24 h, daytime, morning, nighttime, and 1 h maximum PM 10 were associated with 0.15% (95% confidence interval 0.02–0.28%), 0.14% (0.01–0.27%), 0.10% (0.03–0.18%), 0.12% (0.03–0.22%), and 0.10% (0.00–0.21%) increases in total mortality, respectively. PM 10 was significantly associated with cardiovascular mortality for 24 h, morning, and nighttime exposures. We did not identify significant associations with respiratory mortality. The results support use of a 24 h averaging time as an appropriate metric for health studies and regulation, particularly for PM 10 and mortality. (letter)

Level set segmentation of medical images based on local region statistics and maximum a posteriori probability.

Science.gov (United States)

Cui, Wenchao; Wang, Yi; Lei, Tao; Fan, Yangyu; Feng, Yan

2013-01-01

This paper presents a variational level set method for simultaneous segmentation and bias field estimation of medical images with intensity inhomogeneity. In our model, the statistics of image intensities belonging to each different tissue in local regions are characterized by Gaussian distributions with different means and variances. According to maximum a posteriori probability (MAP) and Bayes' rule, we first derive a local objective function for image intensities in a neighborhood around each pixel. Then this local objective function is integrated with respect to the neighborhood center over the entire image domain to give a global criterion. In level set framework, this global criterion defines an energy in terms of the level set functions that represent a partition of the image domain and a bias field that accounts for the intensity inhomogeneity of the image. Therefore, image segmentation and bias field estimation are simultaneously achieved via a level set evolution process. Experimental results for synthetic and real images show desirable performances of our method.

In utero exposure to benzene increases embryonic c-Myb and Pim-1 protein levels in CD-1 mice

International Nuclear Information System (INIS)

Wan, Joanne; Winn, Louise M.

2008-01-01

Benzene is a known human leukemogen, but its role as an in utero leukemogen remains controversial. Epidemiological studies have correlated parental exposure to benzene with an increased incidence of childhood leukemias. We hypothesize that in utero exposure to benzene may cause leukemogenesis by affecting the embryonic c-Myb/Pim-1 signaling pathway and that this is mediated by oxidative stress. To investigate this hypothesis, pregnant CD-1 mice were treated with either 800 mg/kg of benzene or corn oil (i.p.) on days 10 and 11 of gestation and in some cases pretreated with 25 kU/kg of PEG-catalase. Phosphorylated and total embryonic c-Myb and Pim-1 protein levels were assessed using Western blotting and maternal and embryonic oxidative stress were assessed by measuring reduced to oxidized glutathione ratios. Our results show increased oxidative stress at 4 and 24 h after exposure, increased phosphorylated Pim-1 protein levels 4 h after benzene exposure, and increased Pim-1 levels at 24 and 48 h after benzene exposure. Embryonic c-Myb levels were elevated at 24 h after exposure. PEG-catalase pretreatment prevented benzene-mediated increases in embryonic c-Myb and Pim-1 protein levels, and benzene-induced oxidative stress. These results support a role for ROS in c-Myb and Pim-1 alterations after in utero benzene exposure

Occupational exposure of NRM spectrometrists to static and radiofrequency fields

International Nuclear Information System (INIS)

Berlana, Tania; Ubeda, Alejandro

2017-01-01

Occupational exposure to static and radiofrequency fields emitted by nuclear magnetic resonance spectrometers was assessed through systematic field metering during operation of 19 devices in nine research centers. Whereas no measurable levels of radiofrequency radiation were registered outside the spectrometers, significant exposure to static field was detected, with maximum values recorded at the user s hand (B = 683.00 mT) and head thorax (B = 135.70 mT) during spectrometer manipulation. All values were well below the exposure limits set by the European standard for workers protection against the effects of acute field exposure only. As for potential effects of chronic exposure, waiting for more complete knowledge, adoption of technical and operational strategies for exposure minimizing is advisable. In this respect, the data revealed that compared with standard magnetic shielding, ultra-shield technology allows a 20-65-fold reduction of the field strength received by the operator. (authors)

Elevated lead levels from e-waste exposure are linked to decreased olfactory memory in children.

Science.gov (United States)

Zhang, Bo; Huo, Xia; Xu, Long; Cheng, Zhiheng; Cong, Xiaowei; Lu, Xueling; Xu, Xijin

2017-12-01

Lead (Pb) is a developmental neurotoxicant and can cause abnormal development of the nervous system in children. Hence, the aim of this study was to investigate the effect of Pb exposure on child olfactory memory by correlating the blood Pb levels of children in Guiyu with olfactory memory tests. We recruited 61 preschool children, 4- to 7-years of age, from Guiyu and 57 children from Haojiang. The mean blood Pb level of Guiyu children was 9.40 μg/dL, significantly higher than the 5.04 μg/dL mean blood Pb level of Haojiang children. In addition, approximately 23% of Guiyu children had blood Pb levels exceeding 10.00 μg/dL. The correlation analysis showed that blood Pb levels in children highly correlated with e-waste contact (r s  = 0.393). Moreover, the mean concentration of serum BDNF in Guiyu children (35.91 ng/ml) was higher than for Haojiang (28.10 ng/ml) and was positively correlated with blood Pb levels. Both item and source olfactory memory tests at 15 min, 5 h and 24 h after odor exposure showed that scores were lower in Guiyu children indicative of reduced olfactory memory in Guiyu children. Olfactory memory tests scores negatively correlated with blood Pb and serum BDNF levels, but were positively associated with parental education levels. At the same time, scores of both tests on children in the high blood Pb level group (blood Pb levels > 5.00 μg/dL) were lower than those in the low blood Pb level group (blood Pb levels ≤ 5.00 μg/dL), implying that Pb exposure decreases olfactory memory in children. Our findings suggest that Pb exposure in e-waste recycling and dismantling areas could result in an increase in serum BDNF level and a decrease in child olfactory memory, in addition, BDNF might be involved in olfactory memory impairment. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Internal Exposure Levels of PAHs of Primary School Students in Guangzhou].

Science.gov (United States)

Su, Hui; Zhao, Bo; Zhang, Su-kun; Liu, Shan; Ren, Ming-zhong; Li, Jie; Shi, Xiao-xia

2015-12-01

In order to investigate the internal exposure levels of polycyclic aromatic hydrocarbons (PAHs) in primary school students of Guangzhou, the research collected urine of 78 and 86 primary school students from two primary schools in the summer of 2014, one school located in the ordinary residential area and the other in the industrial area. The contents of 10 kinds of OH-PAHs were tested by the rapid liquid chromatography coupled to triple quadruple tandem mass spectrometry. The results showed that the concentrations of total OH-PAHs in primary school students in the residential zone ranged from 0.83 µmol · mol⁻¹ to 80.63 µmol · mol⁻¹, while those in industrial area ranged from 1.06 µmol · mol⁻¹ to 72.47 µmol · mol⁻¹. The geometric average concentrations were 6.18 µmol · mol⁻¹ and 6.47 µmol · mol⁻¹, respectively, and there was no statistical significance between them (P > 0.05). Comparison of the exposure levels of different components of PAHs in the two areas found that all the OH-PAHs had no significant difference except for the levels of 1- OHP (P transportation emissions.

The regulation of starch accumulation in Panicum maximum Jacq ...

African Journals Online (AJOL)

... decrease the starch level. These observations are discussed in relation to the photosynthetic characteristics of P. maximum. Keywords: accumulation; botany; carbon assimilation; co2 fixation; growth conditions; mesophyll; metabolites; nitrogen; nitrogen levels; nitrogen supply; panicum maximum; plant physiology; starch; ...

Assessment of Relevant Exposure Pathways in Scenario of Reuse of Very Low Level Radioactive Steel in Tunnel Constructions

International Nuclear Information System (INIS)

Hrncir, T.; Necas, V.

2012-01-01

Decommissioning process and related management of generated radioactive materials during this process became important topics during last several years because of continuously increasing number of nuclear power plant approaching the end of their lifetime. The very low level radioactive waste category includes considerable amount of materials arising from decommissioning. In line with international incentives of optimization of the waste management process, alternative concepts of recycling and reuse of materials are considered. One of these concepts of such optimization is the conditional release of materials with their subsequent recycling and reuse in industrial or nuclear sector. This paper is devoted to an option of recycling and reuse of conditionally released steel in industrial sector, specifically in motorway tunnel constructions. It is assumed that very low level radioactive steel would be released and reused in form of steel reinforcing components, such as steel nets and bars, assembled in primary and secondary lining of motorway tunnel. Assessment of exposure pathways relevant for construction, operation and post-operation period was performed. The computational tool VISIPLAN 3D ALARA was used for calculation of external individual effective dose for personnel constructing the tunnel and for members of the public driving through already built motorway tunnel. The simulation software GOLDSIM was used for the assessment of internal exposure pathways. GOLDSIM environment enables modelling of degradation processes and transport of radionuclides through unsaturated and saturated zone of subsoil. There are international recommendations available for the concept of release of radioactive materials into the environment derived from the principles that the individual effective dose received by critical individual must not exceed some tens of microSv/yr. Dose limits 10 microSv/yr or 50 microSv/yr considering specific conditions are stated in Slovak legislation

A survey of medical exposure during X-ray diagnosis in Aomori

International Nuclear Information System (INIS)

Kon, Masanori; Fukushi, Shouji; Oota, Fumio; Kawamura, Kouji; Shinohe, Tetsuo; Suwa, Kouki; Fujii, Kiyosuke; Yamagami, Hirofumi

2000-01-01

The purpose of this project was to survey medical exposure doses in Aomori Prefecture and compare them with guidance levels for X-ray diagnosis. A questionnaire survey on X-ray diagnosis was conducted at the main medical institutions in the prefecture. The questionnaire asked about technical conditions, and replies were obtained from 72.2% of the 79 institutions. The medical exposure doses (entrance surface doses) were calculated from the results of the questionnaires by the modified numerical dose determination (NDD) method. The distribution of the entrance surface doses at each site was calculated as the 1st quartile, median, 3rd quartile, average, standard deviation, maximum value and minimum value, by the quartile method. The distribution of exposed doses at each site showed a similar pattern with that of the national distribution. Some institutions used higher doses than the Japanese proposed guidance levels and International Atomic Energy Agency (IAEA) guidance levels. Re-assessment of radiographic conditions and photosensitive materials is needed to reduce exposure doses. (K.H.)

Association of hypothyroidism with low-level arsenic exposure in rural West Texas

International Nuclear Information System (INIS)

Gong, Gordon; Basom, Janet; Mattevada, Sravan; Onger, Frederick

2015-01-01

It has been reported recently that a higher airborne arsenic level was correlated with higher urinary arsenic concentration and lower serum thyroxin level among urban policemen and rural highway workmen in Italy. The current study was to determine whether exposure to low-level arsenic groundwater (2–22 µg/L) is associated with hypothyroidism among 723 participants (118 male and 267 female Hispanics; 108 male and 230 female non-Hispanic whites, NHW) living in rural West Texas counties. Arsenic and iodine levels in their groundwater used for drinking and or cooking were estimated by the inverse distance weighted (IDW) interpolation technique. Groundwater arsenic was ≥8 µg/L in 36% of the subjects' wells while iodine concentration was <1 µg/L in 91% of their wells. Logistic regression analysis showed that arsenic in groundwater ≥8 µg/L and cumulative arsenic exposure (groundwater arsenic concentration multiplied by the number of years living in the current address) but not groundwater iodine concentration were significant predictors for hypothyroidism among Hispanics (p<0.05) but not NHW after adjusting for covariates such as age, gender, annual household income and health insurance coverage. The ethnic difference may be due to a marginally higher percentage of Hispanics (p=0.0622) who lived in areas with groundwater arsenic ≥8 µg/L compared with NHW. The prevalence of hypothyroidism was significantly higher in Hispanics or NHW of this rural cohort than the national prevalence. Measures should be taken to reduce arsenic in drinking water in order to prevent hypothyroidism in rural areas. - Highlights: • We determined if arsenic exposure is associated with hypothyroidism in rural Texas. • Groundwater arsenic level is associated with hypothyroidism among Hispanics only. • The rate of hypothyroidism in rural Texas was higher than the US general population

Association of hypothyroidism with low-level arsenic exposure in rural West Texas

Energy Technology Data Exchange (ETDEWEB)

Gong, Gordon, E-mail: gordon.gong@ttuhsc.edu [F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Sciences Center, Lubbock, TX (United States); Basom, Janet [F. Marie Hall Institute for Rural and Community Health, Texas Tech University Health Sciences Center, Lubbock, TX (United States); Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX (United States); Mattevada, Sravan [Department of Internal Medicine, University of North Texas Health Science Center, Fort Worth, TX (United States); Onger, Frederick [Department of Family and Community Medicine, Texas Tech University Health Sciences Center, Lubbock, TX (United States)

2015-04-15

It has been reported recently that a higher airborne arsenic level was correlated with higher urinary arsenic concentration and lower serum thyroxin level among urban policemen and rural highway workmen in Italy. The current study was to determine whether exposure to low-level arsenic groundwater (2–22 µg/L) is associated with hypothyroidism among 723 participants (118 male and 267 female Hispanics; 108 male and 230 female non-Hispanic whites, NHW) living in rural West Texas counties. Arsenic and iodine levels in their groundwater used for drinking and or cooking were estimated by the inverse distance weighted (IDW) interpolation technique. Groundwater arsenic was ≥8 µg/L in 36% of the subjects' wells while iodine concentration was <1 µg/L in 91% of their wells. Logistic regression analysis showed that arsenic in groundwater ≥8 µg/L and cumulative arsenic exposure (groundwater arsenic concentration multiplied by the number of years living in the current address) but not groundwater iodine concentration were significant predictors for hypothyroidism among Hispanics (p<0.05) but not NHW after adjusting for covariates such as age, gender, annual household income and health insurance coverage. The ethnic difference may be due to a marginally higher percentage of Hispanics (p=0.0622) who lived in areas with groundwater arsenic ≥8 µg/L compared with NHW. The prevalence of hypothyroidism was significantly higher in Hispanics or NHW of this rural cohort than the national prevalence. Measures should be taken to reduce arsenic in drinking water in order to prevent hypothyroidism in rural areas. - Highlights: • We determined if arsenic exposure is associated with hypothyroidism in rural Texas. • Groundwater arsenic level is associated with hypothyroidism among Hispanics only. • The rate of hypothyroidism in rural Texas was higher than the US general population.

Occupational exposure to electromagnetic fields in physiotherapy departments

International Nuclear Information System (INIS)

Macca, I.; Scapellato, M. L.; Carrieri, M.; Di Bisceglie, A. P.; Saia, B.; Bartolucci, G. B.

2008-01-01

To assess occupational exposure to electromagnetic fields, 11 microwave (MW), 4 short-wave diathermy and 15 magneto therapy devices were analysed in eight physiotherapy departments. Measurements taken at consoles and environmental mapping showed values above European Directive 2004/40/EC and ACGIH exposure limits at ∼50 cm from MW applicators (2.45 GHz) and above the Directive magnetic field limit near the diathermy unit (27.12 MHz). Levels in front of MW therapy applicators decreased rapidly with distance and reduction in power; this may not always occur in work environments where nearby metal structures (chairs, couches, etc.) may reflect or perturb electromagnetic fields. Large differences in stray field intensities were found for various MW applicators. Measurements of power density strength around MW electrodes confirmed radiation fields between 30 deg. and 150 deg., with a peak at 90 deg., in front of the cylindrical applicator and maximum values between 30 deg. and 150 deg. over the whole range of 180 deg. for the rectangular parabolic applicator. Our results reveal that although most areas show substantially low levels of occupational exposure to electromagnetic fields in physiotherapy units, certain cases of over-occupational exposure limits do exist. (authors)

The relationship between blood lead levels and occupational exposure in a pregnant population

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Osmel La-Llave-León

2016-12-01

Full Text Available Abstract Background Pregnant women exposed to lead are at risk of suffering reproductive damages, such as miscarriage, preeclampsia, premature delivery and low birth weight. Despite that the workplace offers the greatest potential for lead exposure, there is relatively little information about occupational exposure to lead during pregnancy. This study aims to assess the association between blood lead levels and occupational exposure in pregnant women from Durango, Mexico. Methods A cross-sectional study was carried out in a population of 299 pregnant women. Blood lead was measured in 31 women who worked in jobs where lead is used (exposed group and 268 who did not work in those places (control group. Chi-square test was applied to compare exposed and control groups with regard to blood lead levels. Odds ratio (OR and 95% confidence intervals (CI were calculated. Multivariable regression analysis was applied to determine significant predictors of blood lead concentrations in the exposed group. Results Exposed women had higher blood lead levels than those in the control group (4.00 ± 4.08 μg/dL vs 2.65 ± 1.75 μg/dL, p = 0.002. Furthermore, women in the exposed group had 3.82 times higher probability of having blood lead levels ≥ 5 μg/dL than those in the control group. Wearing of special workwear, changing clothes after work, living near a painting store, printing office, junkyard or rubbish dump, and washing the workwear together with other clothes resulted as significant predictors of elevated blood lead levels in the exposed group. Conclusions Pregnant working women may be at risk of lead poisoning because of occupational and environmental exposure. The risk increases if they do not improve the use of protective equipment and their personal hygiene.

The relationship between blood lead levels and occupational exposure in a pregnant population.

Science.gov (United States)

La-Llave-León, Osmel; Salas Pacheco, José Manuel; Estrada Martínez, Sergio; Esquivel Rodríguez, Eloísa; Castellanos Juárez, Francisco X; Sandoval Carrillo, Ada; Lechuga Quiñones, Angélica María; Vázquez Alanís, Fernando; García Vargas, Gonzalo; Méndez Hernández, Edna Madai; Duarte Sustaita, Jaime

2016-12-07

Pregnant women exposed to lead are at risk of suffering reproductive damages, such as miscarriage, preeclampsia, premature delivery and low birth weight. Despite that the workplace offers the greatest potential for lead exposure, there is relatively little information about occupational exposure to lead during pregnancy. This study aims to assess the association between blood lead levels and occupational exposure in pregnant women from Durango, Mexico. A cross-sectional study was carried out in a population of 299 pregnant women. Blood lead was measured in 31 women who worked in jobs where lead is used (exposed group) and 268 who did not work in those places (control group). Chi-square test was applied to compare exposed and control groups with regard to blood lead levels. Odds ratio (OR) and 95% confidence intervals (CI) were calculated. Multivariable regression analysis was applied to determine significant predictors of blood lead concentrations in the exposed group. Exposed women had higher blood lead levels than those in the control group (4.00 ± 4.08 μg/dL vs 2.65 ± 1.75 μg/dL, p = 0.002). Furthermore, women in the exposed group had 3.82 times higher probability of having blood lead levels ≥ 5 μg/dL than those in the control group. Wearing of special workwear, changing clothes after work, living near a painting store, printing office, junkyard or rubbish dump, and washing the workwear together with other clothes resulted as significant predictors of elevated blood lead levels in the exposed group. Pregnant working women may be at risk of lead poisoning because of occupational and environmental exposure. The risk increases if they do not improve the use of protective equipment and their personal hygiene.

Postnatal odorant exposure induces peripheral olfactory plasticity at the cellular level.

Science.gov (United States)

Cadiou, Hervé; Aoudé, Imad; Tazir, Bassim; Molinas, Adrien; Fenech, Claire; Meunier, Nicolas; Grosmaitre, Xavier

2014-04-02

Mammalian olfactory sensory neurons (OSNs) form the primary elements of the olfactory system. Inserted in the olfactory mucosa lining of the nasal cavity, they are exposed to the environment and their lifespan is brief. Several reports say that OSNs are regularly regenerated during the entire life and that odorant environment affects the olfactory epithelium. However, little is known about the impact of the odorant environment on OSNs at the cellular level and more precisely in the context of early postnatal olfactory exposure. Here we exposed MOR23-green fluorescent protein (GFP) and M71-GFP mice to lyral or acetophenone, ligands for MOR23 or M71, respectively. Daily postnatal exposure to lyral induces plasticity in the population of OSNs expressing MOR23. Their density decreases after odorant exposure, whereas the amount of MOR23 mRNA and protein remain stable in the whole epithelium. Meanwhile, quantitative PCR indicates that each MOR23 neuron has higher levels of olfactory receptor transcripts and also expresses more CNGA2 and phosphodiesterase 1C, fundamental olfactory transduction pathway proteins. Transcript levels return to baseline after 4 weeks recovery. Patch-clamp recordings reveal that exposed MOR23 neurons respond to lyral with higher sensitivity and broader dynamic range while the responses' kinetics were faster. These effects are specific to the odorant-receptor pair lyral-MOR23: there was no effect of acetophenone on MOR23 neurons and no effect of acetophenone and lyral on the M71 population. Together, our results clearly demonstrate that OSNs undergo specific anatomical, molecular, and functional adaptation when chronically exposed to odorants in the early stage of life.

Effects of low-level exposure to xenobiotics present in paints on oxidative stress in workers.

Science.gov (United States)

Moro, Angela M; Charão, Mariele; Brucker, Natália; Bulcão, Rachel; Freitas, Fernando; Guerreiro, Gilian; Baierle, Marília; Nascimento, Sabrina; Waechter, Fernanda; Hirakata, Vânia; Linden, Rafael; Thiesen, Flávia V; Garcia, Solange Cristina

2010-09-15

Paints are composed of an extensive variety of hazardous substances, such as organic solvents and heavy metals. Biomonitoring is an essential tool for assessing the risk to occupational health. Thus, this study analyzed the levels of biomarkers of exposure for toluene, xylene, styrene, ethylbenzene, and lead, as well as the oxidative stress biomarker alterations in painters of an industry. Lipid peroxidation biomarker (MDA), delta-aminolevulinate dehydratase (ALA-D), nonprotein thyol groups, superoxide dismutase and catalase (CAT) were analyzed in exposed and nonexposed subjects. We estimated which of the paint constituents have the greatest influence on the changes in the biomarkers of oxidative stress in this case of co-exposure. The results demonstrated that despite the fact that all the biomarkers of exposure were below the biological exposure limits, the MDA levels and antioxidant enzyme activities were increased, while nonprotein thyol groups and ALA-D levels were decreased in painters when compared with nonexposed subjects. After statistic test, toluene could be suggested as the principal factor responsible for increased lipid peroxidation and inhibition of ALA-D enzyme; however, further studies on the inhibition of ALA-D enzyme by toluene are necessary. Copyright 2010 Elsevier B.V. All rights reserved.

Maximum coherent superposition state achievement using a non-resonant pulse train in non-degenerate three-level atoms

International Nuclear Information System (INIS)

Deng, Li; Niu, Yueping; Jin, Luling; Gong, Shangqing

2010-01-01

The coherent superposition state of the lower two levels in non-degenerate three-level Λ atoms is investigated using the accumulative effects of non-resonant pulse trains when the repetition period is smaller than the decay time of the upper level. First, using a rectangular pulse train, the accumulative effects are re-examined in the non-resonant two-level atoms and the modified constructive accumulation equation is analytically given. The equation shows that the relative phase and the repetition period are important in the accumulative effect. Next, under the modified equation in the non-degenerate three-level Λ atoms, we show that besides the constructive accumulation effect, the use of the partial constructive accumulation effect can also achieve the steady state of the maximum coherent superposition state of the lower two levels and the latter condition is relatively easier to manipulate. The analysis is verified by numerical calculations. The influence of the external levels in such a case is also considered and we find that it can be avoided effectively. The above analysis is also applicable to pulse trains with arbitrary envelopes.

Occupational Noise Exposure among Toll Tellers at Toll Plaza in Malaysia

Science.gov (United States)

Azmi, Sharifah Nadya Syed; Dawal, Siti Zawiah Md; Ya, Tuan Mohammad Yusoff Shah Tuan; Saidin, Hamidi

2010-10-01

Toll tellers working at toll plaza have potential of exposure to high noise from the vehicles especially for the peak level of sound emitted by the heavy vehicles. However, occupational exposures in this workplace have not been adequately characterized and identified. Occupational noise exposure among toll tellers at toll plaza was assessed using Sound Level Meter, Noise Dosimeter and through questionnaire survey. These data were combined to estimate the work shift exposure level and health impacts to the toll tellers by using statistical analysis. Noise Dosimeter microphone was located at the hearing zone of the toll teller which working inside the toll booth and full-period measurements were collected for each work shift. The measurements were taken at 20 toll booths from 6.00 am to 2.00 pm for 5 days. 71 respondents participated in the survey to identify the symptoms of noise induced hearing loss and other health related problems among toll tellers. Results of this study indicated that occupational noise exposure among toll tellers for Mean Continuous Equivalent Level, Leq was 79.2±1.4 dB(A), Mean Maximum Level, Lmax was 107.8±3.6 dB(A) and Mean Peak Level, Lpeak was 136.6±9.9 dB. The Peak Level reported statistically significantly at 140 dB, the level of TLV recommended by ACGIH. The research findings indicated that the primary risk exposure to toll tellers comes from noise that emitted from heavy vehicles. Most of the toll tellers show symptoms of noise induced hearing loss and annoyed by the sources of noise at the toll plaza.

Estimation of quantitative levels of diesel exhaust exposure and the health impact in the contemporary Australian mining industry.

Science.gov (United States)

Peters, Susan; de Klerk, Nicholas; Reid, Alison; Fritschi, Lin; Musk, Aw Bill; Vermeulen, Roel

2017-03-01

To estimate quantitative levels of exposure to diesel exhaust expressed by elemental carbon (EC) in the contemporary mining industry and to describe the excess risk of lung cancer that may result from those levels. EC exposure has been monitored in Western Australian miners since 2003. Mixed-effects models were used to estimate EC levels for five surface and five underground occupation groups (as a fixed effect) and specific jobs within each group (as a random effect). Further fixed effects included sampling year and duration, and mineral mined. On the basis of published risk functions, we estimated excess lifetime risk of lung cancer mortality for several employment scenarios. Personal EC measurements (n=8614) were available for 146 different jobs at 124 mine sites. The mean estimated EC exposure level for surface occupations in 2011 was 14 µg/m 3 for 12 hour shifts. Levels for underground occupation groups ranged from 18 to 44 µg/m 3 . Underground diesel loader operators had the highest exposed specific job: 59 µg/m 3 . A lifetime career (45 years) as a surface worker or underground miner, experiencing exposure levels as estimated for 2011 (14 and 44 µg/m 3 EC), was associated with 5.5 and 38 extra lung cancer deaths per 1000 males, respectively. EC exposure levels in the contemporary Australian mining industry are still substantial, particularly for underground workers. The estimated excess numbers of lung cancer deaths associated with these exposures support the need for implementation of stringent occupational exposure limits for diesel exhaust. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Global levels of radiation exposure: Latest international findings

International Nuclear Information System (INIS)

Gonzalez, A.J.

1993-01-01

The radiation exposure of the world's population has recently been reviewed by the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR). UNSCEAR has reconfirmed that the normal operation of all peaceful nuclear installations contributes insignificantly to the global exposure to radiation. Even taking into account all the nuclear accidents to date (including Chernobyl), the additional exposure would be equivalent to only about 20 days of natural exposure. Military uses of nuclear energy have committed the world to most of the radiation exposure caused by human activities

The Effects of a Maximal Power Training Cycle on the Strength, Maximum Power, Vertical Jump Height and Acceleration of High-Level 400-Meter Hurdlers

Science.gov (United States)

Balsalobre-Fernández, Carlos; Tejero-González, Carlos Mª; del Campo-Vecino, Juan; Alonso-Curiel, Dionisio

2013-01-01

The aim of this study was to determine the effects of a power training cycle on maximum strength, maximum power, vertical jump height and acceleration in seven high-level 400-meter hurdlers subjected to a specific training program twice a week for 10 weeks. Each training session consisted of five sets of eight jump-squats with the load at which each athlete produced his maximum power. The repetition maximum in the half squat position (RM), maximum power in the jump-squat (W), a squat jump (SJ), countermovement jump (CSJ), and a 30-meter sprint from a standing position were measured before and after the training program using an accelerometer, an infra-red platform and photo-cells. The results indicated the following statistically significant improvements: a 7.9% increase in RM (Z=−2.03, p=0.021, δc=0.39), a 2.3% improvement in SJ (Z=−1.69, p=0.045, δc=0.29), a 1.43% decrease in the 30-meter sprint (Z=−1.70, p=0.044, δc=0.12), and, where maximum power was produced, a change in the RM percentage from 56 to 62% (Z=−1.75, p=0.039, δc=0.54). As such, it can be concluded that strength training with a maximum power load is an effective means of increasing strength and acceleration in high-level hurdlers. PMID:23717361

Exposure to unusually high indoor radon levels

International Nuclear Information System (INIS)

Rasheed, F.N.

1993-01-01

Unusually high indoor radon concentrations were reported in a small village in western Tyrol, Austria. The authors have measured the seasonal course of indoor radon concentrations in 390 houses of this village. 71% of houses in winter and 33% in summer, showed radon values on the ground floor above the Austrian action level of 400 Bq/cm 3 . This proportion results in an unusually high indoor radon exposure of the population. The radon source was an 8,700-year-old rock slide of granite gneiss, the largest of the alpine crystalline rocks. It has a strong emanating power because its rocks are heavily fractured and show a slightly increased uranium content. Previous reports show increased lung cancer mortality, myeloid leukemia, kidney cancer, melanoma, and prostate cancer resulting from indoor radon exposure. However, many studies fail to provide accurate information on indoor radon concentrations, classifying them merely as low, intermediate, and high, or they record only minor increases in indoor radon concentrations. Mortality data for 1970-91 were used to calculate age and sex standardized mortality rates (SMR) for 51 sites of carcinoma. The total population of Tyrol were controls. A significantly higher risk was recorded for lung cancer. The high SMR for lung cancer in female subjects is especially striking. Because the numbers were low for the other cancer sites, these were combined in one group to calculate the SMR. No significant increase in SMR was found for this group

The Association between Exposure to Environmental Bisphenol A and Gonadotropic Hormone Levels among Men.

Directory of Open Access Journals (Sweden)

Hong Liang

Full Text Available Bisphenol A (BPA is an extensively used chemical with endocrine disrupting properties. Although animal and in vivo studies have suggested possible effects of BPA on levels of gonadotropic hormones, human studies are limited and inconclusive. The study examined whether environmental BPA exposure was associated with gonadotropic hormones levels in men. A total of 560 men aged 18-55 years were recruited from Sandu County, Guizhou Province, China. We collected urine samples for measurement of BPA, and blood samples for measurement of reproductive hormones. We examined serum levels of follicle-stimulating hormone (FSH, luteinizing hormone (LH, and total testosterone (T. Relative risk (RR was obtained by log-binominal regression to explore the association between urinary BPA level and hormone levels. BPA was detected in 70.4% of urine samples, with a geometric mean of 0.50 μg/gCr. Men with detectable levels of BPA had a 1.52-fold increased risk of having a high LH level (>75th percentile when compared with men with undetectable levels of BPA, after adjustment for potential confounders (95% confidence interval (CI: 1.04-2.21. The association persisted and slightly intensified among current smokers (adjusted RR (aRR = 1.76, 95%CI: 1.05-2.95, while it weakened among non-smokers (aRR = 1.17, 95%CI: 0.69-1.96. Urinary BPA level was associated with an increased FSH level among smokers (aRR = 1.64, 95%CI: 1.01-2.67. Urinary BPA level was inversely associated with total T level among males with body max index (BMI ≥25 kg/m2 although this association was of borderline significance (aRR = 0.52, 95%CI: 0.26-1.05. In conclusion, environmental exposure to BPA was associated with increased serum levels of LH and FSH in male smokers, along with decreased serum levels of total T in men with BMI≥25 kg/m2. These findings suggest that the effects of environmental BPA exposure on hormone levels might be modified by smoking and BMI.

Quality assurance of external exposure measurement for national survey of environmental natural radioactive level

International Nuclear Information System (INIS)

Yue Qingyu

1995-01-01

This paper summarizes the quality assurance work of external exposure measurement for national survey of environmental natural radioactive level. It mainly introduces instrumentation used in external exposure measurement and its properties, the measurement results of three times of national in-site intercomparison, and in-site sample check results of measurement results from 29 provinces, cities and autonomous regions and Wuhan, Baotou cities

The use of environmental metabolomics to determine glyphosate level of exposure in rapeseed (Brassica napus L.) seedlings

International Nuclear Information System (INIS)

Petersen, Iben Lykke; Tomasi, Giorgio; Sorensen, Hilmer; Boll, Esther S.; Hansen, Hans Christian Bruun; Christensen, Jan H.

2011-01-01

Metabolic profiling in plants can be used to differentiate between treatments and to search for biomarkers for exposure. A methodology for processing Ultra-High-Performance Liquid Chromatography-Diode-Array-Detection data is devised. This methodology includes a scheme for selecting informative wavelengths, baseline removal, retention time alignment, selection of relevant retention times, and principal component analysis (PCA). Plant crude extracts from rapeseed seedling exposed to sublethal concentrations of glyphosate are used as a study case. Through this approach, plants exposed to concentrations down to 5 μM could be distinguished from the controls. The compounds responsible for this differentiation were partially identified and were different from those specific for high exposure samples, which suggests that two different responses to glyphosate are elicited in rapeseed depending on the level of exposure. The PCA loadings indicate that a combination of other metabolites could be more sensitive than the response of shikimate to detect glyphosate exposure. - Highlights: → A method for processing UHPLC-DAD data for plant metabolic profiling is devised. → The metabolic profiling approach is more sensitive to glyphosate exposure than shikimate. → Plants exposed to concentrations down to 5 μM can be distinguished from the controls. → Two different responses to glyphosate may be elicited in rapeseed depending on the level of exposure. - A novel untargeted environmental metabololomic approach is used to detect low-level glyphosate exposure of rapeseed seedlings.

The use of environmental metabolomics to determine glyphosate level of exposure in rapeseed (Brassica napus L.) seedlings

Energy Technology Data Exchange (ETDEWEB)

Petersen, Iben Lykke; Tomasi, Giorgio; Sorensen, Hilmer; Boll, Esther S.; Hansen, Hans Christian Bruun [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark); Christensen, Jan H., E-mail: jch@life.ku.dk [Department of Basic Sciences and Environment, Faculty of Life Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871 Frederiksberg C (Denmark)

2011-10-15

Metabolic profiling in plants can be used to differentiate between treatments and to search for biomarkers for exposure. A methodology for processing Ultra-High-Performance Liquid Chromatography-Diode-Array-Detection data is devised. This methodology includes a scheme for selecting informative wavelengths, baseline removal, retention time alignment, selection of relevant retention times, and principal component analysis (PCA). Plant crude extracts from rapeseed seedling exposed to sublethal concentrations of glyphosate are used as a study case. Through this approach, plants exposed to concentrations down to 5 {mu}M could be distinguished from the controls. The compounds responsible for this differentiation were partially identified and were different from those specific for high exposure samples, which suggests that two different responses to glyphosate are elicited in rapeseed depending on the level of exposure. The PCA loadings indicate that a combination of other metabolites could be more sensitive than the response of shikimate to detect glyphosate exposure. - Highlights: > A method for processing UHPLC-DAD data for plant metabolic profiling is devised. > The metabolic profiling approach is more sensitive to glyphosate exposure than shikimate. > Plants exposed to concentrations down to 5 {mu}M can be distinguished from the controls. > Two different responses to glyphosate may be elicited in rapeseed depending on the level of exposure. - A novel untargeted environmental metabololomic approach is used to detect low-level glyphosate exposure of rapeseed seedlings.

Study of radiation exposure profiles in interventional radiology professionals; Estudo dos perfis de exposicao a radiacao em profissionais de radiologia intervencionista

Energy Technology Data Exchange (ETDEWEB)

Bacchim Neto, Fernando A.; Alves, Allan F.F.; Alvarez, Matheus; Rosa, Maria E.D.; Miranda, Jose R.A.; Freitas, Carlos C.M. de; Moura, Regina; Pina, Diana R. de, E-mail: fernando.bacchim@gmail.com [Universidade Estadual Paulista Julio de Mesquita Filho (UNESP), Botucatu, SP (Brazil)

2014-07-01

Interventional Radiology is the radiology area that provides the highest dose values to the medical staff. Recent surveys show that personal dosimeters may underestimate the radiation dose values in interventional physicians, especially in the extremities and crystalline. The objective of this work was to study the exposure levels to radiation from medical staff in different interventional radiology procedures. Therefore, thermoluminescent dosimeters type LiF: Mg, Ti (TLD-100) were used positioned in the main interventional physician and an assistant in the following locations: some inches below the crystalline, thyroid, chest, gonads, hand and foot. By comparing the values obtained with the annual reference dose levels in workers, maximum numbers of annual procedures were found. Altogether, there were 23 procedures evaluated: 10 diagnostics, 9 angioplasties and 4 stents. The maximum number of annual procedures were estimated by discounting the percentages of attenuation of radiological protection. For procedures of the type diagnosis, angioplasty and stent for the main interventionist, the maximum number of annual procedures were 641, 445 and 113 respectively, while for the interventionists assistants were 930, 1202 and 215 respectively. As each interventionist body region is subject to different levels of exposure, detailed studies of exposure in each region provide better conclusions about what actions are necessary to ensure radiological protection professionals.

Cigarettes with different nicotine levels affect sensory perception and levels of biomarkers of exposure in adult smokers.

Science.gov (United States)

McKinney, Diana L; Frost-Pineda, Kimberly; Oldham, Michael J; Fisher, Michael T; Wang, Jingzhu; Gogova, Maria; Kobal, Gerd

2014-07-01

Few clinical studies involving cigarettes have provided a comprehensive picture of smoke exposure, test article characterization, and insights into sensory properties combined. The purpose of these pilot studies was to determine whether cigarettes with different levels of nicotine but similar tar levels would affect sensory experience or smoking behavior so as to significantly alter levels of selected biomarkers of exposure (BOE). In 2 confined, double-blind studies, 120 adult smokers switched from Marlboro Gold cigarettes at baseline to either 1 of 2 lower nicotine cigarettes or 1 of 2 higher nicotine cigarettes and then to the other cigarette after 5 days. Urinary excretion of exposure biomarkers (nicotine equivalents [NE], total and free 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol [NNAL], 1-hydroxypyrene, and 3-hydroxypropyl mercapturic acid) as well as carboxyhemoglobin and plasma cotinine were measured at baseline, Day 5, and Day 10. Daily cigarette consumption was monitored and sensory characteristics were rated for each cigarette. With higher nicotine yield, urine NE, urine total NNAL, and plasma cotinine increased while nonnicotine BOE decreased without changes in cigarette consumption. In contrast, with lower nicotine yield, urine NE, urine total NNAL, and plasma cotinine dropped while nonnicotine BOE and cigarettes per day increased. Higher nicotine cigarettes were rated harsher and stronger than at baseline while lower nicotine cigarettes were less strong. All 4 test cigarettes were highly disliked. These studies demonstrate that abrupt increases or decreases in nicotine and the resulting sensory changes impact BOE through changes in intensity or frequency of smoking. © The Author 2014. Published by Oxford University Press on behalf of the Society for Research on Nicotine and Tobacco. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Radiation exposure in the young level 1 trauma patient: a retrospective review.

Science.gov (United States)

Gottschalk, Michael B; Bellaire, Laura L; Moore, Thomas

2015-01-01

Computed tomography (CT) has become an increasingly popular and powerful tool for clinicians managing trauma patients with life-threatening injuries, but the ramifications of increasing radiation burden on individual patients are not insignificant. This study examines a continuous series of 337 patients less than 40 years old admitted to a level 1 trauma center during a 4-month period. Primary outcome measures included number of scans; effective dose of radiation from radiographs and CT scans, respectively; and total effective dose from both sources over patients' hospital stays. Several variables, including hospital length of stay, initial Glasgow Coma Scale score, and Injury Severity Score, correlated with greater radiation exposure. Blunt trauma victims were more prone to higher doses than those with penetrating or combined penetrating and blunt trauma. Location and mechanism of injury were also found to correlate with radiation exposure. Trauma patients as a group are exposed to high levels of radiation from X-rays and CT scans, and CT scans contribute a very high proportion (91.3% ± 11.7%) of that radiation. Certain subgroups of patients are at a particularly high risk of exposure, and greater attention to cumulative radiation dose should be paid to patients with the above mentioned risk factors.

Evaluation of medical radiation exposure in pediatric interventional radiology procedures

Energy Technology Data Exchange (ETDEWEB)

Navarro, Valeria Coelho Costa; Navarro, Marcus Vinicius Teixeira; Oliveira, Aline da Silva Pacheco, E-mail: vccnavarro@gmail.com [Instituto Federal de Educacao, Ciencia e Tecnologia da Bahia (IFBA), Salvador, BA (Brazil); Maia, Ana Figueiredo [Universidade Federal de Sergipe (UFS), Aracaju, SE (Brazil); Oliveira, Adriano Dias Dourado [Sociedade Brasileira de Hemodinamica e Cardiologia Intervencionista, Salvador, BA (Brazil)

2012-07-15

Objective: To evaluate pediatric radiation exposure in procedures of interventional radiology in two hospitals in the Bahia state, aiming at contributing to delineate the scenario at the state and national levels. The knowledge of exposure levels will allow an evaluation of the necessity of doses optimization, considering that peculiarities of radiology and pediatrics become even more significant in interventional radiology procedures which involve exposure to higher radiation doses. Materials and Methods: A total of 32 procedures were evaluated in four rooms of the two main hospitals performing pediatric interventional radiology procedures in the Bahia state. Air kerma rate and kerma-area product were evaluated in 27 interventional cardiac and 5 interventional brain procedures. Results: Maximum values for air kerma rate and kerma-area product and air kerma obtained in cardiac procedures were, respectively, 129.9 Gy.cm{sup 2} and 947.0 mGy; and, for brain procedures were 83.3 Gy.cm{sup 2} and 961.0 mGy. Conclusion: The present study results showed exposure values up to 14 times higher than those found in other foreign studies, and approximating those found for procedures in adults. Such results demonstrate excessive exposure to radiation, indicating the need for constant procedures optimization and evaluation of exposure rates. (author)

Occupational radiation exposure in the GDR in 1978

International Nuclear Information System (INIS)

Poulheim, K.F.; Rothe, W.; Scheler, R.

1980-01-01

In 1978, radiation workers were monitored for external and internal radiation exposure on the basis of film badges (37,980 persons), measurements with a whole-body counter (186 persons) and analyses of biosamples (144 persons). According to the film badge data, the monthly over-exposures (more than 4 mGy) totalled 427. In 13 cases the monthly exposure exceeded 30 mGy, 8 persons received annual doses in the range of 50 to 120 mGy, and the highest annual dose was above 250 mGy. Also, annual collective and annual per caput doses have been given for the exposed population as a whole and some subgroups. Based on model considerations, the internal radiation exposure situation resulting from unintentional intakes of radionuclides has been assessed in terms of committed dose equivalents to members of two selected groups of radiation workers: (a) persons with more-than-average internal contamination levels; (b) persons subjected to frequent individual monitoring. Except for some organ doses, the individual internal radiation exposure was well below one-tenth the maximum permissible dose. (author)

[Exposure to fluorides from drinking water in the city of Aguascalientes, Mexico].

Science.gov (United States)

Trejo-Vázquez, R; Bonilla-Petriciolet, A

2001-08-01

Determine the fluoride content in all the wells that supply drinking water to the city of Aguascalientes, Mexico, in order to establish the population's degree of exposure. The fluoride content of the 126 wells that supply drinking water to the city of Aguascalientes was determined, using the SPADNS method, in accordance with two Mexican regulations, NMX-AA-77-1982 and NMX-014-SSAI-1993. Using that data, we created fluoride isopleth maps showing the distribution of fluoride concentrations in the water supplies for the city of Aguascalientes. We also estimated exposure doses for the city's inhabitants. The mean analysis uncertainty was 3.9%. Seventy-three wells had a fluoride concentration of" 1.5 mg/L, which was the maximum permissible value set by the Mexican standards then in effect. All the maximum exposure doses surpassed the minimum risk level set by Agency for Toxic Substances and Disease Registry (ATSDR) of the Department of Health and Human Services of the United States of America. In the children under 1 year of age, even the minimum does was slightly higher than the ATSDR risk level. From estimating the fluoride exposure doses caused by water consumption in the city of Aguascalientes and comparing those doses with ones from other states in Mexico, we concluded that the fluoride intake in Aguascalientes represents a potential risk for inhabitants' health. The fluoride content of the city's drinking water should be reduced to 0.69 mg/L.

Estimation of quantitative levels of diesel exhaust exposure and the health impact in the contemporary Australian mining industry

NARCIS (Netherlands)

Peters, Susan; de Klerk, Nicholas; Reid, Alison; Fritschi, Lin; Musk, Aw Bill; Vermeulen, Roel

2017-01-01

OBJECTIVES: To estimate quantitative levels of exposure to diesel exhaust expressed by elemental carbon (EC) in the contemporary mining industry and to describe the excess risk of lung cancer that may result from those levels. METHODS: EC exposure has been monitored in Western Australian miners

The association between low level exposures to ambient air pollution and term low birth weight: a retrospective cohort study

Directory of Open Access Journals (Sweden)

Stieb David

2006-02-01

Full Text Available Abstract Background Studies in areas with relatively high levels of air pollution have found some positive associations between exposures to ambient levels of air pollution and several birth outcomes including low birth weight (LBW. The purpose of this study was to examine the association between LBW among term infants and ambient air pollution, by trimester of exposure, in a region of lower level exposures. Methods The relationship between LBW and ambient levels of particulate matter up to 10 um in diameter (PM10, sulfur dioxide (SO2 and ground-level ozone (O3 was evaluated using the Nova Scotia Atlee Perinatal Database and ambient air monitoring data from the Environment Canada National Air Pollution Surveillance Network and the Nova Scotia Department of Environment. The cohort consisted of live singleton births (≥37 weeks of gestation between January1,1988 and December31,2000. Maternal exposures to air pollution were assigned to women living within 25 km of a monitoring station at the time of birth. Air pollution was evaluated as a continuous and categorical variable (using quartile exposures for each trimester and relative risks were estimated from logistic regression, adjusted for confounding variables. Results There were 74,284 women with a term, singleton birth during the study period and with exposure data. In the analyses unadjusted for year of birth, first trimester exposures in the highest quartile for SO2 and PM10suggested an increased risk of delivering a LBW infant (relative risk = 1.36, 95% confidence interval = 1.04 to 1.78 for SO2 exposure and relative risk = 1.33, 95% confidence interval = 1.02 to 1.74 for PM10. After adjustment for birth year, the relative risks were attenuated somewhat and not statistically significant. A dose-response relationship for SO2 was noted with increasing levels of exposure. No statistically significant effects were noted for ozone. Conclusion Our results suggest that exposure during the first

Temporary threshold shifts from exposures to equal equivalent continuous A-weighted sound pressure level

DEFF Research Database (Denmark)

Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

2014-01-01

the assumptions made using the A-weighting curve for the assessment of hearing damage. By modifying exposure ratings to compensate for the build-up of energy at mid and high-frequencies (above 1 kHz) due to the presence of the listener in the sound field and for the levels below an effect threshold that does...... not induce changes in hearing (equivalent quiet levels), ratings of the sound exposure that reflect the observed temporary changes in auditory function can be obtained.......According to existing methods for the assessment of hearing damage, signals with the same A-weighted equivalent level should pose the same hazard to the auditory system. As a measure of hazard, it is assumed that Temporary Thresholds Shifts (TTS) reflect the onset of alterations to the hearing...

County-Level Climate Uncertainty for Risk Assessments: Volume 18 Appendix Q - Historical Maximum Near-Surface Wind Speed.

Energy Technology Data Exchange (ETDEWEB)

Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

2017-06-01

This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconom ic impacts. The full report is contained in 27 volumes.

County-Level Climate Uncertainty for Risk Assessments: Volume 4 Appendix C - Historical Maximum Near-Surface Air Temperature.

Energy Technology Data Exchange (ETDEWEB)

Backus, George A.; Lowry, Thomas Stephen; Jones, Shannon M; Walker, La Tonya Nicole; Roberts, Barry L; Malczynski, Leonard A.

2017-06-01

This report uses the CMIP5 series of climate model simulations to produce country- level uncertainty distributions for use in socioeconomic risk assessments of climate change impacts. It provides appropriate probability distributions, by month, for 169 countries and autonomous-areas on temperature, precipitation, maximum temperature, maximum wind speed, humidity, runoff, soil moisture and evaporation for the historical period (1976-2005), and for decadal time periods to 2100. It also provides historical and future distributions for the Arctic region on ice concentration, ice thickness, age of ice, and ice ridging in 15-degree longitude arc segments from the Arctic Circle to 80 degrees latitude, plus two polar semicircular regions from 80 to 90 degrees latitude. The uncertainty is meant to describe the lack of knowledge rather than imprecision in the physical simulation because the emphasis is on unfalsified risk and its use to determine potential socioeconomic impacts. The full report is contained in 27 volumes.

Experimental evaluation of the exposure level onboard Czech Airlines aircraft - measurements verified the routine method

International Nuclear Information System (INIS)

Ploc, O.; Spurny, F.; Turek, K.; Kovar, I.

2008-01-01

Air-crew members are exposed to ionizing radiation due to their work on board of air-crafts. The International Commission on Radiological Protection (ICRP) in 1990 recommends that exposure to cosmic radiation in the operation of jet aircraft should be recognised as occupational exposure. Czech air transport operators are therefore obliged to ensure: - Air-crew members to be well informed about the exposure level and health risks; - An analysis of complete exposure level of aircraft crew and its continuing monitoring in cases of exceeding the informative value 1 mSv; - A compliance of limit 1 mSv during pregnancy Since 1998, after receiving a proper accreditation, the Department of Radiation Dosimetry of Nuclear Physics Institute of Czech Academy of Sciences (DRD) is the competent dosimetric service realized requirements of Notice No.307 of the State Office for Nuclear Safety concerning air-crew exposure (paragraphs 87-90). The DRD has developed routine method of personal dosimetry of aircraft crew in 1998 which has been applied after receiving a proper accreditation in the same year. DRD therefore helps Czech airlines a.s. (CSA) with their legislative obligations mentioned above, and in return, once per four years, in terms of business contract, CSA allows scientific measurements performed by DRD onboard its air-crafts with the aim to verify the method of routine individual monitoring of aircraft crew exposure. (authors)

Low-level lead exposure effects on spatial reference memory and working memory in rats

Institute of Scientific and Technical Information of China (English)

Xinhua Yang; Ping Zhou; Yonghui Li

2009-01-01

BACKGROUND: Studies have demonstrated that lead exposure can result in cognitive dysfunction and behavior disorders. However, lead exposure impairments vary under different experimental conditions.OBJECTIVE: To detect changes in spatial learning and memory following low-level lead exposure in rats, in Morris water maze test under the same experimental condition used to analyze lead exposure effects on various memory types and learning processes.DESIGN AND SETTING: The experiment was conducted at the Animal Laboratory, Institute of Psychology, Chinese Academy of Science between February 2005 and March 2006. One-way analysis of variance (ANOVA) and behavioral observations were performed.MATERIALS: Sixteen male, healthy, adult, Sprague Dawley rats were randomized into normal control and lead exposure groups (n = 8).METHODS: Rats in the normal control group were fed distilled water, and those in the lead exposure group were fed 250 mL of 0.05% lead acetate once per day. At day 28, all rats performed the Morris water maze test, consisting of four phases: space navigation, probe test, working memory test, and visual cue test.MAIN OUTCOME MEASURES: Place navigation in the Morris water maze was used to evaluate spatial learning and memory, probe trials for spatial reference memory, working memory test for spatial working memory, and visual cue test for non-spatial cognitive function. Perkin-Elmer Model 300 Atomic Absorption Spectrometer was utilized to determine blood lead levels in rats.RESULTS: (1) In the working memory test, the time to reach the platform remained unchanged between the control and lead exposure groups (F(1,1) = 0.007, P = 0.935). A visible decrease in escape latencies was observed in each group (P = 0.028). However, there was no significant difference between the two groups (F(1,1) = 1.869, P = 0.193). The working memory probe test demonstrated no change between the two groups in the time spent in the target quadrant during the working memory probe test

Targeted maximum likelihood estimation for a binary treatment: A tutorial.

Science.gov (United States)

Luque-Fernandez, Miguel Angel; Schomaker, Michael; Rachet, Bernard; Schnitzer, Mireille E

2018-04-23

When estimating the average effect of a binary treatment (or exposure) on an outcome, methods that incorporate propensity scores, the G-formula, or targeted maximum likelihood estimation (TMLE) are preferred over naïve regression approaches, which are biased under misspecification of a parametric outcome model. In contrast propensity score methods require the correct specification of an exposure model. Double-robust methods only require correct specification of either the outcome or the exposure model. Targeted maximum likelihood estimation is a semiparametric double-robust method that improves the chances of correct model specification by allowing for flexible estimation using (nonparametric) machine-learning methods. It therefore requires weaker assumptions than its competitors. We provide a step-by-step guided implementation of TMLE and illustrate it in a realistic scenario based on cancer epidemiology where assumptions about correct model specification and positivity (ie, when a study participant had 0 probability of receiving the treatment) are nearly violated. This article provides a concise and reproducible educational introduction to TMLE for a binary outcome and exposure. The reader should gain sufficient understanding of TMLE from this introductory tutorial to be able to apply the method in practice. Extensive R-code is provided in easy-to-read boxes throughout the article for replicability. Stata users will find a testing implementation of TMLE and additional material in the Appendix S1 and at the following GitHub repository: https://github.com/migariane/SIM-TMLE-tutorial. © 2018 The Authors. Statistics in Medicine published by John Wiley & Sons Ltd.

Tributyltin Exposure Alters Cytokine Levels in Mouse Serum

Science.gov (United States)

Lawrence, Shanieek; Pellom, Samuel T.; Shanker, Anil; Whalen, Margaret M.

2016-01-01

Tributyltin (TBT), a toxic environmental contaminant, has been widely utilized for various industrial, agricultural and household purposes. Its usage has led to a global contamination and its bioaccumulation in aquatic organisms and terrestrial mammals. Previous studies suggest that TBT has debilitating effects on the overall immune function of animals, rendering them more vulnerable to diseases. TBT (at concentrations that have been detected in human blood) alters secretion of inflammatory cytokines from human lymphocytes ex vivo. Thus, it is important to determine if specified levels of TBT can alter levels of cytokines in an in vivo system. Mice were exposed to biologically relevant concentrations of TBT (200, 100 or 25 nM final concentrations). The quantitative determination of interferon (IFN)-γ, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL2, IL5, IL7, IL12βp40, IL13, IL15, KC, MIP1β, MIP2 and RANTES was performed in mouse sera by MAGPIX analysis and Western blot. Results indicated alterations (both decreases and increases) in several cytokines. The pro-inflammatory cytokines IFNγ, TNFα, IL-1β, IL-2, IL5, IL12βp40, and IL-15 were altered as were the chemokines MIP-1 and RANTES and the anti-inflammatory cytokine IL-13. Increases in IFNγ and TNFα were seen in serum of mice exposed to TBT for less than 24 hr. IL1-β, IL-12βp40, IL-5 and IL-15 were also modulated in mouse serum depending on the specific experiment and the exposure concentration. IL-2 was consistently decreased in mouse serum when animals were exposed to TBT. There were also TBT-induced increases in MIP-1β, RANTES, and IL-13. These results from human and murine samples clearly suggest that TBT exposures modulate the secretion inflammatory cytokines. PMID:27602597

Music exposure improves spatial cognition by enhancing the BDNF level of dorsal hippocampal subregions in the developing rats.

Science.gov (United States)

Xing, Yingshou; Chen, Wenxi; Wang, Yanran; Jing, Wei; Gao, Shan; Guo, Daqing; Xia, Yang; Yao, Dezhong

2016-03-01

Previous research has shown that dorsal hippocampus plays an important role in spatial memory process. Music exposure can enhance brain-derived neurotrophic factor (BDNF) expression level in dorsal hippocampus (DH) and thus enhance spatial cognition ability. But whether music experience may affect different subregions of DH in the same degree remains unclear. Here, we studied the effects of exposure to Mozart K.448 on learning behavior in developing rats using the classical Morris water maze task. The results showed that early music exposure could enhance significantly learning performance of the rats in the water maze test. Meanwhile, the BDNF/TrkB level of dorsal hippocampus CA3 (dCA3) and dentate gyrus (dDG) was significantly enhanced in rats exposed to Mozart music as compared to those without music exposure. In contrast, the BDNF/TrkB level of dorsal hippocampus CA1 (dCA1) was not affected. The results suggest that the spatial memory improvement by music exposure in rats may be associated with the enhanced BDNF/TrkB level of dCA3 and dDG. Copyright © 2016 Elsevier Inc. All rights reserved.

The reduction of retinal autofluorescence caused by light exposure.

Science.gov (United States)

Morgan, Jessica I W; Hunter, Jennifer J; Merigan, William H; Williams, David R

2009-12-01

A prior study showed that long exposure to 568-nm light at levels below the maximum permissible exposure safety limit produces retinal damage preceded by a transient reduction in the autofluorescence of retinal pigment epithelial (RPE) cells in vivo. The present study shows how the effects of exposure power and duration combine to produce this autofluorescence reduction and find the minimum exposure causing a detectable autofluorescence reduction. Macaque retinas were imaged using a fluorescence adaptive optics scanning laser ophthalmoscope to resolve individual RPE cells in vivo. The retina was exposed to 568-nm light over a square subtending 0.5 degrees with energies ranging from 1 to 788 J/cm(2), where power and duration were independently varied. In vivo exposures of 5 J/cm(2) and higher caused an immediate decrease in autofluorescence followed by either full autofluorescence recovery (exposures or= 247 J/cm(2)). No significant autofluorescence reduction was observed for exposures of 2 J/cm(2) and lower. Reciprocity of exposure power and duration held for the exposures tested, implying that the total energy delivered to the retina, rather than its distribution in time, determines the amount of autofluorescence reduction. That reciprocity held is consistent with a photochemical origin, which may or may not cause retinal degeneration. The implementation of safe methods for delivering light to the retina requires a better understanding of the mechanism causing autofluorescence reduction. Finally, RPE imaging was demonstrated using light levels that do not cause a detectable reduction in autofluorescence.

Studying DDT Susceptibility at Discriminating Time Intervals Focusing on Maximum Limit of Exposure Time Survived by DDT Resistant Phlebotomus argentipes (Diptera: Psychodidae): an Investigative Report.

Science.gov (United States)

Rama, Aarti; Kesari, Shreekant; Das, Pradeep; Kumar, Vijay

2017-07-24

Extensive application of routine insecticide i.e., dichlorodiphenyltrichloroethane (DDT) to control Phlebotomus argentipes (Diptera: Psychodidae), the proven vector of visceral leishmaniasis in India, had evoked the problem of resistance/tolerance against DDT, eventually nullifying the DDT dependent strategies to control this vector. Because tolerating an hour-long exposure to DDT is not challenging enough for the resistant P. argentipes, estimating susceptibility by exposing sand flies to insecticide for just an hour becomes a trivial and futile task.Therefore, this bioassay study was carried out to investigate the maximum limit of exposure time to which DDT resistant P. argentipes can endure the effect of DDT for their survival. The mortality rate of laboratory-reared DDT resistant strain P. argentipes exposed to DDT was studied at discriminating time intervals of 60 min and it was concluded that highly resistant sand flies could withstand up to 420 min of exposure to this insecticide. Additionally, the lethal time for female P. argentipes was observed to be higher than for males suggesting that they are highly resistant to DDT's toxicity. Our results support the monitoring of tolerance limit with respect to time and hence points towards an urgent need to change the World Health Organization's protocol for susceptibility identification in resistant P. argentipes.

Predicting adult pulmonary ventilation volume and wearing complianceby on-board accelerometry during personal level exposure assessments

Science.gov (United States)

Rodes, C. E.; Chillrud, S. N.; Haskell, W. L.; Intille, S. S.; Albinali, F.; Rosenberger, M. E.

2012-09-01

BackgroundMetabolic functions typically increase with human activity, but optimal methods to characterize activity levels for real-time predictions of ventilation volume (l min-1) during exposure assessments have not been available. Could tiny, triaxial accelerometers be incorporated into personal level monitors to define periods of acceptable wearing compliance, and allow the exposures (μg m-3) to be extended to potential doses in μg min-1 kg-1 of body weight? ObjectivesIn a pilot effort, we tested: 1) whether appropriately-processed accelerometer data could be utilized to predict compliance and in linear regressions to predict ventilation volumes in real-time as an on-board component of personal level exposure sensor systems, and 2) whether locating the exposure monitors on the chest in the breathing zone, provided comparable accelerometric data to other locations more typically utilized (waist, thigh, wrist, etc.). MethodsPrototype exposure monitors from RTI International and Columbia University were worn on the chest by a pilot cohort of adults while conducting an array of scripted activities (all volumes in-situ. For the subset of participants with complete data (n = 22), linear regressions were constructed (processed accelerometric variable versus ventilation rate) for each participant and exposure monitor type, and Pearson correlations computed to compare across scenarios. ResultsTriaxial accelerometer data were demonstrated to be adequately sensitive indicators for predicting exposure monitor wearing compliance. Strong linear correlations (R values from 0.77 to 0.99) were observed for all participants for both exposure sensor accelerometer variables against ventilation volume for recumbent, sedentary, and ambulatory activities with MET values ˜volume data. Computing accelerometric standard deviations allowed good sensitivity for compliance assessments even for sedentary activities. These pilot findings supported the hypothesis that a common linear

Exposure to ambient air pollution--does it affect semen quality and the level of reproductive hormones?

Science.gov (United States)

Radwan, Michał; Jurewicz, Joanna; Polańska, Kinga; Sobala, Wojciech; Radwan, Paweł; Bochenek, Michał; Hanke, Wojciech

2016-01-01

Ambient air pollution has been associated with a variety of reproductive disorders. However, a limited amount of research has been conducted to examine the association between air pollution and male reproductive outcomes, specifically semen quality. The present study was designed to address the hypothesis that exposure to fluctuating levels of specific air pollutants adversely affects sperm parameters and the level of reproductive hormones. The study population consisted of 327 men who were attending an infertility clinic in Łodź, Poland for diagnostic purposes and who had normal semen concentration of 15-300 mln/ml. All participants were interviewed and provided a semen sample. Air quality data were obtained from AirBase database. The statistically significant association was observed between abnormalities in sperm morphology and exposure to all examined air pollutants (PM10, PM2.5, SO2, NOX, CO). Exposure to air pollutants (PM10, PM2.5, CO, NOx) was also negatively associated with the level of testosterone. Additional exposure to PM2.5, PM10 increase the percentage of cells with immature chromatin (HDS). The present study provides suggestive evidence of an association between ambient air pollution and sperm quality. Further research is needed to explore this association in more detail. Individual precise exposure assessment would be needed for more detailed risk characterization.

Impact of a smoking ban in hospitality venues on second hand smoke exposure: a comparison of exposure assessment methods.

Science.gov (United States)

Rajkumar, Sarah; Huynh, Cong Khanh; Bauer, Georg F; Hoffmann, Susanne; Röösli, Martin

2013-06-04

In May 2010, Switzerland introduced a heterogeneous smoking ban in the hospitality sector. While the law leaves room for exceptions in some cantons, it is comprehensive in others. This longitudinal study uses different measurement methods to examine airborne nicotine levels in hospitality venues and the level of personal exposure of non-smoking hospitality workers before and after implementation of the law. Personal exposure to second hand smoke (SHS) was measured by three different methods. We compared a passive sampler called MoNIC (Monitor of NICotine) badge, to salivary cotinine and nicotine concentration as well as questionnaire data. Badges allowed the number of passively smoked cigarettes to be estimated. They were placed at the venues as well as distributed to the participants for personal measurements. To assess personal exposure at work, a time-weighted average of the workplace badge measurements was calculated. Prior to the ban, smoke-exposed hospitality venues yielded a mean badge value of 4.48 (95%-CI: 3.7 to 5.25; n = 214) cigarette equivalents/day. At follow-up, measurements in venues that had implemented a smoking ban significantly declined to an average of 0.31 (0.17 to 0.45; n = 37) (p = 0.001). Personal badge measurements also significantly decreased from an average of 2.18 (1.31-3.05 n = 53) to 0.25 (0.13-0.36; n = 41) (p = 0.001). Spearman rank correlations between badge exposure measures and salivary measures were small to moderate (0.3 at maximum). Nicotine levels significantly decreased in all types of hospitality venues after implementation of the smoking ban. In-depth analyses demonstrated that a time-weighted average of the workplace badge measurements represented typical personal SHS exposure at work more reliably than personal exposure measures such as salivary cotinine and nicotine.

Exposure to environmental levels of waterborne cadmium impacts corticosteroidogenic and metabolic capacities, and compromises secondary stressor performance in rainbow trout

International Nuclear Information System (INIS)

Sandhu, Navdeep; McGeer, James C.; Vijayan, Mathilakath M.

2014-01-01

Highlights: •Low level chronic waterborne cadmium exposure did not evoke a plasma cortisol response in rainbow trout. •Chronic cadmium exposure increases liver and gill metabolic capacities. •Chronic cadmium exposure disrupts head kidney steroidogenic capacity. •Chronic cadmium exposure disrupts glucocorticoid and mineralocorticoid receptor protein expressions in target tissues. •Chronic cadmium exposure compromises physiological performances to a secondary stressor in trout. -- Abstract: The physiological responses to waterborne cadmium exposure have been well documented; however, few studies have examined animal performances at low exposure concentrations of this metal. We tested the hypothesis that longer-term exposure to low levels of cadmium will compromise the steroidogenic and metabolic capacities, and reduce the cortisol response to a secondary stressor in fish. To test this, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 0 (control), 0.75 or 2.0 μg/L waterborne cadmium in a flow-through system and were sampled at 1, 7 and 28 d of exposure. There were only very slight disturbances in basal plasma cortisol, lactate or glucose levels in response to cadmium exposure over the 28 d period. Chronic cadmium exposure significantly affected key genes involved in corticosteroidogenesis, including melanocortin 2 receptor, steroidogenic acute regulatory protein and cytochrome P450 side chain cleavage enzyme. At 28 d, the high cadmium exposure group showed a significant drop in the glucocorticoid receptor and mineralocorticoid receptor protein expressions in the liver and brain, respectively. There were also perturbations in the metabolic capacities in the liver and gill of cadmium-exposed trout. Subjecting these fish to a secondary handling disturbance led to a significant attenuation of the stressor-induced plasma cortisol, glucose and lactate levels in the cadmium groups. Collectively, although trout appears to adjust to subchronic exposure

Exposure to environmental levels of waterborne cadmium impacts corticosteroidogenic and metabolic capacities, and compromises secondary stressor performance in rainbow trout

Energy Technology Data Exchange (ETDEWEB)

Sandhu, Navdeep [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada); McGeer, James C. [Department of Biology, Wilfrid Laurier University, Waterloo, Ontario N2L 3C5 (Canada); Vijayan, Mathilakath M., E-mail: matt.vijayan@ucalgary.ca [Department of Biology, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)

2014-01-15

Highlights: •Low level chronic waterborne cadmium exposure did not evoke a plasma cortisol response in rainbow trout. •Chronic cadmium exposure increases liver and gill metabolic capacities. •Chronic cadmium exposure disrupts head kidney steroidogenic capacity. •Chronic cadmium exposure disrupts glucocorticoid and mineralocorticoid receptor protein expressions in target tissues. •Chronic cadmium exposure compromises physiological performances to a secondary stressor in trout. -- Abstract: The physiological responses to waterborne cadmium exposure have been well documented; however, few studies have examined animal performances at low exposure concentrations of this metal. We tested the hypothesis that longer-term exposure to low levels of cadmium will compromise the steroidogenic and metabolic capacities, and reduce the cortisol response to a secondary stressor in fish. To test this, juvenile rainbow trout (Oncorhynchus mykiss) were exposed to 0 (control), 0.75 or 2.0 μg/L waterborne cadmium in a flow-through system and were sampled at 1, 7 and 28 d of exposure. There were only very slight disturbances in basal plasma cortisol, lactate or glucose levels in response to cadmium exposure over the 28 d period. Chronic cadmium exposure significantly affected key genes involved in corticosteroidogenesis, including melanocortin 2 receptor, steroidogenic acute regulatory protein and cytochrome P450 side chain cleavage enzyme. At 28 d, the high cadmium exposure group showed a significant drop in the glucocorticoid receptor and mineralocorticoid receptor protein expressions in the liver and brain, respectively. There were also perturbations in the metabolic capacities in the liver and gill of cadmium-exposed trout. Subjecting these fish to a secondary handling disturbance led to a significant attenuation of the stressor-induced plasma cortisol, glucose and lactate levels in the cadmium groups. Collectively, although trout appears to adjust to subchronic exposure

Current practices for maintaining occupational exposures ALARA at low-level waste disposal sites

International Nuclear Information System (INIS)

Hadlock, D.E.; Herrington, W.N.; Hooker, C.D.; Murphy, D.W.; Gilchrist, R.L.

1983-12-01

The United States Nuclear Regulatory Commission contracted with Pacific Northwest Laboratory (PNL) to provide technical assistance in establishing operational guidelines, with respect to radiation control programs and methods of minimizing occupational radiation exposure, at Low-Level Waste (LLW) disposal sites. The PNL, through site visits, evaluated operations at LLW disposal sites to determine the adequacy of current practices in maintaining occupational exposures as low as is reasonably achievable (ALARA). The data sought included the specifics of: ALARA programs, training programs, external exposure control, internal exposure control, respiratory protection, surveillance, radioactive waste management, facilities and equipment, and external dose analysis. The results of the study indicated the following: The Radiation Protection and ALARA programs at the three commercial LLW disposal sites were observed to be adequate in scope and content compared to similar programs at other types of nuclear facilities. However, it should be noted that there were many areas that could be improved upon to help ensure the health and safety of occupationally exposed individuals

Current practices for maintaining occupational exposures ALARA at low-level waste disposal sites

Energy Technology Data Exchange (ETDEWEB)

Hadlock, D.E.; Herrington, W.N.; Hooker, C.D.; Murphy, D.W.; Gilchrist, R.L.

1983-12-01

The United States Nuclear Regulatory Commission contracted with Pacific Northwest Laboratory (PNL) to provide technical assistance in establishing operational guidelines, with respect to radiation control programs and methods of minimizing occupational radiation exposure, at Low-Level Waste (LLW) disposal sites. The PNL, through site visits, evaluated operations at LLW disposal sites to determine the adequacy of current practices in maintaining occupational exposures as low as is reasonably achievable (ALARA). The data sought included the specifics of: ALARA programs, training programs, external exposure control, internal exposure control, respiratory protection, surveillance, radioactive waste management, facilities and equipment, and external dose analysis. The results of the study indicated the following: The Radiation Protection and ALARA programs at the three commercial LLW disposal sites were observed to be adequate in scope and content compared to similar programs at other types of nuclear facilities. However, it should be noted that there were many areas that could be improved upon to help ensure the health and safety of occupationally exposed individuals.

Sub-acute occupational hypersensitivity pneumonitis due to low-level exposure to diisocyanates in a secretary.

Science.gov (United States)

Schreiber, J; Knolle, J; Sennekamp, J; Schulz, K T; Hahn, J U; Hering, K G; Raulf-Heimsoth, M; Merget, R

2008-09-01

There is virtually no information in the literature about the exposure levels needed to induce hypersensitivity pneumonitis (HP) by diisocyanates. The present study reports a case of occupational HP due to diisocyanates after low-level exposure. A 53-yr-old female never-smoker developed progressive shortness of breath on exertion, cough, fatigue and flu-like symptoms shortly after she began work as a secretary of a car body repair shop. A diagnosis of HP was made 2 yrs later, based on a restrictive ventilatory defect, a reticulonodular and discrete ground-glass pattern on high-resolution computed tomography, lymphocytosis in bronchoalveolar lavage and specific immunoglobulin G antibodies to diisocyanate human serum albumin conjugates in the patient's serum. The diagnosis was confirmed by recovery after exposure cessation and deterioration after re-exposure. Ambient monitoring revealed air concentrations of different diisocyanate monomers below the detection limit in both the patient's work station and in front of the paint spray booths, with the exception of one measurement that showed 4,4-methylenediphenyl diisocyanate concentrations of 3 microg x m(-3) in front of one booth (corresponding to a total reactive isocyanate group concentration of 1 microg x m(-3)). The present authors conclude that concentrations of diisocyanates far below current exposure limits may induce hypersensitivity pneumonitis in susceptible subjects.

Chronic corticosterone exposure reduces hippocampal glycogen level and induces depression-like behavior in mice.

Science.gov (United States)

Zhang, Hui-yu; Zhao, Yu-nan; Wang, Zhong-li; Huang, Yu-fang

2015-01-01

Long-term exposure to stress or high glucocorticoid levels leads to depression-like behavior in rodents; however, the cause remains unknown. Increasing evidence shows that astrocytes, the most abundant cells in the central nervous system (CNS), are important to the nervous system. Astrocytes nourish and protect the neurons, and serve as glycogen repositories for the brain. The metabolic process of glycogen, which is closely linked to neuronal activity, can supply sufficient energy substrates for neurons. The research team probed into the effects of chronic corticosterone (CORT) exposure on the glycogen level of astrocytes in the hippocampal tissues of male C57BL/6N mice in this study. The results showed that chronic CORT injection reduced hippocampal neurofilament light protein (NF-L) and synaptophysin (SYP) levels, induced depression-like behavior in male mice, reduced hippocampal glycogen level and glycogen synthase activity, and increased glycogen phosphorylase activity. The results suggested that the reduction of the hippocampal glycogen level may be the mechanism by which chronic CORT treatment damages hippocampal neurons and induces depression-like behavior in male mice.

Relative sea-level changes and crustal movements in Britain and Ireland since the Last Glacial Maximum

Science.gov (United States)

Shennan, Ian; Bradley, Sarah L.; Edwards, Robin

2018-05-01

The new sea-level database for Britain and Ireland contains >2100 data points from 86 regions and records relative sea-level (RSL) changes over the last 20 ka and across elevations ranging from ∼+40 to -55 m. It reveals radically different patterns of RSL as we move from regions near the centre of the Celtic ice sheet at the last glacial maximum to regions near and beyond the ice limits. Validated sea-level index points and limiting data show good agreement with the broad patterns of RSL change predicted by current glacial isostatic adjustment (GIA) models. The index points show no consistent pattern of synchronous coastal advance and retreat across different regions, ∼100-500 km scale, indicating that within-estuary processes, rather than decimetre- and centennial-scale oscillations in sea level, produce major controls on the temporal pattern of horizontal shifts in coastal sedimentary environments. Comparisons between the database and GIA model predictions for multiple regions provide potentially powerful constraints on various characteristics of global GIA models, including the magnitude of MWP1A, the final deglaciation of the Laurentide ice sheet and the continued melting of Antarctica after 7 ka BP.

Rat hippocampal alterations could underlie behavioral abnormalities induced by exposure to moderate noise levels.

Science.gov (United States)

Uran, S L; Aon-Bertolino, M L; Caceres, L G; Capani, F; Guelman, L R

2012-08-30

Noise exposure is known to affect auditory structures in living organisms. However, it should not be ignored that many of the effects of noise are extra-auditory. Previous findings of our laboratory demonstrated that noise was able to induce behavioral alterations that are mainly related to the cerebellum (CE) and the hippocampus (HC). Therefore, the aim of this work was to reveal new data about the vulnerability of developing rat HC to moderate noise levels through the assessment of potential histological changes and hippocampal-related behavioral alterations. Male Wistar rats were exposed to noise (95-97 dB SPL, 2h daily) either for 1 day (acute noise exposure, ANE) or between postnatal days 15 and 30 (sub-acute noise exposure, SANE). Hippocampal histological evaluation as well as short (ST) and long term (LT) habituation and recognition memory assessments were performed. Results showed a mild disruption in the different hippocampal regions after ANE and SANE schemes, along with significant behavioral abnormalities. These data suggest that exposure of developing rats to noise levels of moderate intensity is able to trigger changes in the HC, an extra-auditory structure of the Central Nervous System (CNS), that could underlie the observed behavioral effects. Copyright © 2012 Elsevier B.V. All rights reserved.

Challenges in evaluating PM concentration levels, commuting exposure, and mask efficacy in reducing PM exposure in growing, urban communities in a developing country.

Science.gov (United States)

Patel, Disa; Shibata, Tomoyuki; Wilson, James; Maidin, Alimin

2016-02-01

Particulate matter (PM) contributes to an increased risk of respiratory and cardiovascular illnesses, cancer, and preterm birth complications. This project assessed PM exposure in Eastern Indonesia's largest city, where air quality has not been comprehensively monitored. We examined the efficacy of wearing masks as an individual intervention effort to reduce in-transit PM exposures. Handheld particulate counters were used to investigate ambient air quality for spatial analysis, as well as the differences in exposure to PM2.5 and PM10 (μg/m(3)) by different transportation methods [e.g. motorcycle (n=97), pete-pete (n=53), and car (n=55); note: n=1 means 1m(3) of air sample]. Mask efficacy to reduce PM exposure was evaluated [e.g. surgical masks (n=39), bandanas (n=52), and motorcycle masks (n=39)]. A Monte Carlo simulation was used to provide a range of uncertainty in exposure assessment. Overall PM10 levels (91±124 μg/m(3)) were elevated compared to the World Health Organization (WHO)'s 24-hour air quality guideline (50 μg/m(3)). While average PM2.5 levels (9±14 μg/m(3)) were below the WHO's guideline (25 μg/m(3)), measurements up to 139 μg/m(3) were observed. Compared to cars, average motorcycle and pete-pete PM exposures were four and three times higher for PM2.5, and 13 and 10 times higher for PM10, respectively. Only surgical masks were consistent in lowering PM2.5 and PM10 (pmasks. Individual interventions can effectively reduce individual PM exposures; however, policy interventions will be needed to improve the overall air quality and create safer transportation. Copyright © 2015 Elsevier B.V. All rights reserved.

The last glacial maximum

Science.gov (United States)

Clark, P.U.; Dyke, A.S.; Shakun, J.D.; Carlson, A.E.; Clark, J.; Wohlfarth, B.; Mitrovica, J.X.; Hostetler, S.W.; McCabe, A.M.

2009-01-01

We used 5704 14C, 10Be, and 3He ages that span the interval from 10,000 to 50,000 years ago (10 to 50 ka) to constrain the timing of the Last Glacial Maximum (LGM) in terms of global ice-sheet and mountain-glacier extent. Growth of the ice sheets to their maximum positions occurred between 33.0 and 26.5 ka in response to climate forcing from decreases in northern summer insolation, tropical Pacific sea surface temperatures, and atmospheric CO2. Nearly all ice sheets were at their LGM positions from 26.5 ka to 19 to 20 ka, corresponding to minima in these forcings. The onset of Northern Hemisphere deglaciation 19 to 20 ka was induced by an increase in northern summer insolation, providing the source for an abrupt rise in sea level. The onset of deglaciation of the West Antarctic Ice Sheet occurred between 14 and 15 ka, consistent with evidence that this was the primary source for an abrupt rise in sea level ???14.5 ka.

An epidemiological study on patient exposure from dental radiography

International Nuclear Information System (INIS)

Ehara, Masahiro

1980-01-01

The gonadal and bone marrow doses received by patients per exposure from dental X-ray examinations are small when compared to those of other medical X-ray procedures. Therefore, the contribution from dental X-ray exposure dose has not been discussed in terms of individual dose, but has always been considered in terms of population dose. However, depending on the peculiarity of the disease involved, some dental patients are considered to be subjected to relatively large doses of diagnostic X-rays. Therefore, from the standpoint of overall radiation protection, it was felt important to estimate the maximum individual dose incurred by diagnostic dental radiography. An epidemiological survey was undertaken at Osaka Dental University Hospital to estimate the maximum radiation exposure doses to various organs by projection. A total of 1301 patients were randomly selected from among persons who had initially visited the Radiology Department and subsequently received many X-ray exposures. The individual exposure dose to each organ was determined by projection based on the type and number of examinations. Results showed that the conditions incurring the maximum exposure dose in individual patients for diagnostic purposes in the dental region was those with ameloblastoma. (author)

ESTIMATION OF EXPOSURE DOSES FOR THE SAFE MANAGEMENT OF NORM WASTE DISPOSAL.

Science.gov (United States)

Jeong, Jongtae; Ko, Nak Yul; Cho, Dong-Keun; Baik, Min Hoon; Yoon, Ki-Hoon

2018-03-16

Naturally occurring radioactive materials (NORM) wastes with different radiological characteristics are generated in several industries. The appropriate options for NORM waste management including disposal options should be discussed and established based on the act and regulation guidelines. Several studies calculated the exposure dose and mass of NORM waste to be disposed in landfill site by considering the activity concentration level and exposure dose. In 2012, the Korean government promulgated an act on the safety control of NORM around living environments to protect human health and the environment. For the successful implementation of this act, we suggest a reference design for a landfill for the disposal of NORM waste. Based on this reference landfill, we estimate the maximum exposure doses and the relative impact of each pathway to exposure dose for three scenarios: a reference scenario, an ingestion pathway exclusion scenario, and a low leach rate scenario. Also, we estimate the possible quantity of NORM waste disposal into a landfill as a function of the activity concentration level of U series, Th series and 40K and two kinds of exposure dose levels, 1 and 0.3 mSv/y. The results of this study can be used to support the establishment of technical bases of the management strategy for the safe disposal of NORM waste.

Radiation exposure in nuclear medicine: real-time measurement

International Nuclear Information System (INIS)

Sylvain, Iara; Bok, Bernard; X. Bichat University, Paris

2002-01-01

French regulations have introduced the use of electronic dosimeters for personnel monitoring of workers. In order to evaluate the exposure from diagnostic procedures to nuclear medicine staff, individual whole-body doses were measured daily with electronic (digital) personal dosimeters during 20 consecutive weeks and correlated with the work load of each day. Personal doses remained always below 20 mu Sv/d under normal working conditions. Radiation exposure levels were highest to tech staff, nurses and stretcher-bearers. The extrapolated annual cumulative doses for all staff remained less than 10% of the maximum legal limit for exposed workers (2 mSv/yr). Electronic dosimeters are not technically justified for routine survey of staff. The high sensitivity and immediate reading of electronic semiconductor dosimeters may become very useful for exposure control under risky working conditions. It may become an important help for optimising radiation protection. (author)

Global levels of histone modifications in peripheral blood mononuclear cells of subjects with exposure to nickel.

Science.gov (United States)

Arita, Adriana; Niu, Jingping; Qu, Qingshan; Zhao, Najuan; Ruan, Ye; Nadas, Arthur; Chervona, Yana; Wu, Fen; Sun, Hong; Hayes, Richard B; Costa, Max

2012-02-01

Occupational exposure to nickel (Ni) is associated with an increased risk for lung and nasal cancers. Ni compounds exhibit weak mutagenic activity, cause gene amplification, and disrupt cellular epigenetic homeostasis. However, the Ni-induced changes in global histone modification levels have only been tested in vitro. This study was conducted in a Chinese population to determine whether occupational exposure to Ni is associated with alterations of global histone modification levels and to evaluate the inter- and intraindividual variance of global histone modification levels. Forty-five subjects with occupational exposure to Ni and 75 referents were recruited. Urinary Ni and global H3K4 trimethylation, H3K9 acetylation, and H3K9 dimethylation levels were measured in peripheral blood mononuclear cells (PBMCs) of subjects. H3K4me3 was elevated in Ni-exposed subjects (0.25% ± 0.11%) compared with referents (0.15% ± 0.04%; p = 0.0004), and H3K9me2 was decreased (Ni-exposed subjects, 0.11% ± 0.05%; referents, 0.15% ± 0.04%; p = 0.003). H3K4me3 was positively (r = 0.4, p = 0.0008) and H3K9ac was negatively (r = 0.1, p = 0.01) associated with urinary Ni. Interindividual variances of H3K4me3, H3K9ac, and H3K9me2 were larger compared with intraindividual variance in both exposure test groups, resulting in reliability coefficients (an estimate of consistency of a set of measurements) of 0.60, 0.67, and 0.79 for H3K4me3, H3K9ac, and H3K9me2, respectively, for Ni-exposed subjects and of 0.75, 0.74, and 0.97, respectively, for referent subjects. The results of this study indicate that occupational exposure to Ni is associated with alterations of global histone modification levels and that measurements of global levels of histone modifications are relatively stable over time in human PBMCs.

Exposure levels to electromagnetic fields in usual operative situations

International Nuclear Information System (INIS)

Bemardi, C; Bemardi, T.; Testoni, G.; Zannoli, R.; Tubertini, O

1997-01-01

In the last few years, the whole population have been repeatedly solicited from media about the possible negative effects of E.M. Fields involved in all the social activities. This determinate the need of evaluations of the risks in different conditions, supported by accurate measurement protocols. This paper describes the procedures and the results of measurements in four different conditions, which involve the whole population and/or workers of a specific field. Results have been used both to increase the knowledge of the E.M. exposure levels and to evaluate the risks, with respect to the National Rules and Guidelines. (authors)

Evaluation and modeling of the parameters affecting fluoride toxicity level in aquatic environments by bioassay method

Directory of Open Access Journals (Sweden)

Hamid Reza Shamsollahi

2014-04-01

Full Text Available Background: Fluoride exists in various forms in nature and water resources. , The rising level of fluoride in water resources due to discharge of industrial effluents can cause toxicity in aquatic organisms. To prevent toxicity, it is necessary to determine maximum fluoride toxicity as well as effluent discharge limits. The aim of this study was to determine the maximum fluoride toxicity and the factors affecting fluoride toxicity to provide a model in order to determine the effluent discharge limits. Methods: Daphnia magna bioassay in the absence of confounding factors was used to determine the maximum level of fluoride toxicity. Then, bioassay was repeated in the presence of the confounding factors (hardness, temperature and exposure time to determine their effects. Results: In the absence of intervening factors, fluoride LC50 levels determined after 24, 48 and 72 hours exposure were 4.9, 46.5 and 38.7 mg/l, respectively.. Also, the influence of confounding factors on LC50 values was reported significant by Minitab software. Conclusion: Increasing the water hardness reduced fluoride toxicity, and increasing the water temperature and exposure time increased fluoride toxicity in aquatic environments. Therefore, while determining the wastewater discharge limit in terms of fluoride concentration, it is essential to take the effect of confounding factors on fluoride toxicity into account in order to prevent toxicity in the open water resources.

Bladder/lung cancer mortality in Blackfoot-disease (BFD)-endemic area villages with low (water arsenic levels--an exploration of the dose-response Poisson analysis.

Science.gov (United States)

Lamm, Steven H; Robbins, Shayhan A; Zhou, Chao; Lu, Jun; Chen, Rusan; Feinleib, Manning

2013-02-01

To examine the analytic role of arsenic exposure on cancer mortality among the low-dose (well water arsenic level villages in the Blackfoot-disease (BFD) endemic area of southwest Taiwan and with respect to the southwest regional data. Poisson analyses of the bladder and lung cancer deaths with respect to arsenic exposure (μg/kg/day) for the low-dose (villages with exposure defined by the village median, mean, or maximum and with or without regional data. Use of the village median well water arsenic level as the exposure metric introduced misclassification bias by including villages with levels >500 μg/L, but use of the village mean or the maximum did not. Poisson analyses using mean or maximum arsenic levels showed significant negative cancer slope factors for models of bladder cancers and of bladder and lung cancers combined. Inclusion of the southwest Taiwan regional data did not change the findings when the model contained an explanatory variable for non-arsenic differences. A positive slope could only be generated by including the comparison population as a separate data point with the assumption of zero arsenic exposure from drinking water and eliminating the variable for non-arsenic risk factors. The cancer rates are higher among the low-dose (villages in the BFD area than in the southwest Taiwan region. However, among the low-dose villages in the BFD area, cancer risks suggest a negative association with well water arsenic levels. Positive differences from regional data seem attributable to non-arsenic ecological factors. Copyright © 2012 Elsevier Inc. All rights reserved.

Low-level radiation

International Nuclear Information System (INIS)

Myers, D.K.

1982-05-01

It is known that the normal incidence of cancer in human populations is increased by exposure to moderately high doses of ionizing radiation. At background radiation levels or at radiation levels which are 100 times greater, the potential health risks are considered to be directly proportional to the total accumulated dose of radiation. Some of the uncertainties associated with this assumption and with the accepted risk estimates have been critically reviewed in this document. The general scientific consensus at present suggests that the accepted risk estimates may exaggerate the actual risk of low levels of sparsely ionizing radiations (beta-, gamma- or X-rays) somewhat but are unlikely to overestimate the actual risks of densely ionizing radiations (fast neutrons, alpha-particles). At the maximum permissible levels of exposure for radiation workers in nuclear power stations, the potential health hazards in terms of life expectancy would be comparable to those encountered in transportation and public utilities or in the construction industry. At the average radiation exposures received by these workers in practice, the potential health hazards are similar to those associated with safe categories of industries. Uranium mining remains a relativly hazardous occupation. In terms of absolute numbers, the genetic hazards, which are less well established, are thought to be smaller than the carcinogenic hazards of radiation when only the first generation is considered but to be of the same order of magnitude as the carcinogenic hazards when the total number of induced genetic disorders is summed over all generations

[A cohort study on association between the first trimester phthalates exposure and fasting blood glucose level in the third trimester].

Science.gov (United States)

Zhang, Y W; Gao, H; Huang, K; Xu, Y Y; Sheng, J; Tao, F B

2017-03-10

Objective: To examine the association between the phthalate exposure in the first trimester and fasting blood glucose level or gestational diabetes mellitus (GDM) in the third trimester in pregnant women. Methods: A total of 3 474 pregnant women, receiving their prenatal examination in Ma' anshan Maternal and Child Health-Care Hospital of Anhui province, were selected from May 2013 to September 2014. Questionnaires were used to collect the information about their socio-demographic characteristics, clinical characteristics and GDM diagnostic results in the first, second and third trimesters. Urine samples and fasting venous blood samples were collected. Concentrations of 7 kinds of phthalate metabolites in urine samples were detected by solid phase extraction-high performance liquid chromatography-tandem mass spectrometry (SPE-HPLC-MS/MS), and multiple linear regression model was used for statistical analyses. Logistic regression analysis on the risk of the first trimester phthalate exposure for GDM in the third trimester was conducted. Results: The prevalence of GDM in this study was 12.8%, monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-n-butyl phthalate (MBP), monobenzyl phthalate (MBzP) and mono-(2-ethyl-5-oxohexyl) phthalate (MEHHP) exposure levels were positively correlated with the fasting blood glucose level in the third trimester ( P levels were negatively correlated with the fasting blood glucose level in the third trimester ( P blood glucose level in both normal group and GDM group. However, MMP, MEP, MBP, MBzP, MEHP and MEOHP exposure levels had influences on the third trimester fasting blood glucose level in normal group but not in GDM group. MMP and MBP exposure might increase the risk of GDM, but MEOHP exposure might reduce the risk of GDM. Conclusion: The phthalate exposure in the first trimester might be associated with the fasting blood glucose level in the third trimester, MMP, MEP, MBP, MBzP and MEHHP concentrations were positively

The ICRP Proposed Maximum Public Dose Constraints of o.3 mSv/y: a Major Issue for the Nuclear Industry

International Nuclear Information System (INIS)

Saint-Pierre, S.; Coates, R.

2004-01-01

The International Commission on Radiological Protection (ICRP) is currently developing a new set of Recommendations on Radiological Protection. A value of 0.3mSv/y for the maximum public dose constraint has been discussed by ICRP. This value represents a major concern for the nuclear industry at large. The primary issue arises from the lack of any new scientific evidence on public health effects from ionising radiation to support, in practice, the proposed reduction by about a factor of 3 (from 1 to 0.3 mSv/y) of the upper bound value for public dose impact from a nuclear activity or site. Such a change would create a de facto limit on public exposure from specific sources at a dose level of about one tenth of average natural background and an even smaller fraction of the typical range of background exposures and exposures from medical sources. This cannot be justified on public health grounds. The WNA supports ICRP's renewed intention, as expressed at the NEA-ICRP Stakeholder Forum in Lanzarote (April 2003), to retain the concept of a public dose limit at 1 mSv/y. We strongly believe that the current system comprising of the dose limit and the ALARA Principle provides the necessary flexibility and tools for regulators to address all situations in all countries. The WNA consider that the question of setting an upper bound dose constraint (below 1 mSv/y) at the country/site specific level is best left for discussion and agreement between the local stakeholders rather than at an international level. When considering the potential practical implications of a maximum dose constraint, it is important to look beyond the very low off-site dose impacts (on the public) resulting from annual routine radioactive discharges of nuclear industrial sites. There are many off-site and on-site practical situations, related to public exposures (both workers and the public) and worker classification as well as activities such transportation, decommissioning and site remediation, for

The ICRP Proposed Maximum Public Dose Constraints of o.3 mSv/y: a Major Issue for the Nuclear Industry

Energy Technology Data Exchange (ETDEWEB)

Saint-Pierre, S.; Coates, R.

2004-07-01

The International Commission on Radiological Protection (ICRP) is currently developing a new set of Recommendations on Radiological Protection. A value of 0.3mSv/y for the maximum public dose constraint has been discussed by ICRP. This value represents a major concern for the nuclear industry at large. The primary issue arises from the lack of any new scientific evidence on public health effects from ionising radiation to support, in practice, the proposed reduction by about a factor of 3 (from 1 to 0.3 mSv/y) of the upper bound value for public dose impact from a nuclear activity or site. Such a change would create a de facto limit on public exposure from specific sources at a dose level of about one tenth of average natural background and an even smaller fraction of the typical range of background exposures and exposures from medical sources. This cannot be justified on public health grounds. The WNA supports ICRP's renewed intention, as expressed at the NEA-ICRP Stakeholder Forum in Lanzarote (April 2003), to retain the concept of a public dose limit at 1 mSv/y. We strongly believe that the current system comprising of the dose limit and the ALARA Principle provides the necessary flexibility and tools for regulators to address all situations in all countries. The WNA consider that the question of setting an upper bound dose constraint (below 1 mSv/y) at the country/site specific level is best left for discussion and agreement between the local stakeholders rather than at an international level. When considering the potential practical implications of a maximum dose constraint, it is important to look beyond the very low off-site dose impacts (on the public) resulting from annual routine radioactive discharges of nuclear industrial sites. There are many off-site and on-site practical situations, related to public exposures (both workers and the public) and worker classification as well as activities such transportation, decommissioning and site remediation

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

Science.gov (United States)

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.

Low-level maternal methylmercury exposure through rice ingestion and potential implications for offspring health

International Nuclear Information System (INIS)

Rothenberg, Sarah E.; Feng Xinbin; Li Ping

2011-01-01

Fish consumption is considered the primary pathway for MeHg (MeHg) exposure; however, MeHg exposure also occurs through rice ingestion. Rice is grown in an aquatic environment and although documented MeHg concentrations in rice are lower compared to fish tissue, human exposures exceed international guidelines in some regions where rice is a staple food and rice MeHg levels are elevated. Studies concerning human health exposure to MeHg should also include populations where maternal MeHg exposure occurs through ingestion of rice. Rice does not contain long-chain polyunsaturated fatty acids, which are associated with confounding developmental outcomes in offspring. Rice is also a staple food for more than half the world's population; therefore, it is critical to investigate the potential health risks of maternal ingestion of rice to the developing fetus, the most susceptible population to the deleterious effects of MeHg. Data concerning MeHg in rice are reviewed and micronutrients in rice are discussed. - Research highlights: → Maternal methylmercury exposure through rice may be important. → Rice does not contain the same micronutrients as fish, but may contain methylmercury. → Effects to offspring from methylmercury without beneficial micronutrients are unknown. - Studies concerning maternal methylmercury exposure and cognitive outcomes for offspring should include populations where rice ingestion is the primary methylmercury exposure pathway.

Low-level maternal methylmercury exposure through rice ingestion and potential implications for offspring health

Energy Technology Data Exchange (ETDEWEB)

Rothenberg, Sarah E., E-mail: rothenberg.sarah@gmail.com [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Feng Xinbin, E-mail: fengxinbin@vip.skleg.cn [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China); Li Ping [State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, 46 Guanshui Lu, Guiyang 550002 (China)

2011-04-15

Fish consumption is considered the primary pathway for MeHg (MeHg) exposure; however, MeHg exposure also occurs through rice ingestion. Rice is grown in an aquatic environment and although documented MeHg concentrations in rice are lower compared to fish tissue, human exposures exceed international guidelines in some regions where rice is a staple food and rice MeHg levels are elevated. Studies concerning human health exposure to MeHg should also include populations where maternal MeHg exposure occurs through ingestion of rice. Rice does not contain long-chain polyunsaturated fatty acids, which are associated with confounding developmental outcomes in offspring. Rice is also a staple food for more than half the world's population; therefore, it is critical to investigate the potential health risks of maternal ingestion of rice to the developing fetus, the most susceptible population to the deleterious effects of MeHg. Data concerning MeHg in rice are reviewed and micronutrients in rice are discussed. - Research highlights: > Maternal methylmercury exposure through rice may be important. > Rice does not contain the same micronutrients as fish, but may contain methylmercury. > Effects to offspring from methylmercury without beneficial micronutrients are unknown. - Studies concerning maternal methylmercury exposure and cognitive outcomes for offspring should include populations where rice ingestion is the primary methylmercury exposure pathway.

Assessment of Tomato (Solanum lycopersicum L. Producers’ Exposure Level to Pesticides, in Kouka and Toussiana (Burkina Faso

Directory of Open Access Journals (Sweden)

Diakalia Son

2018-01-01

Full Text Available To assess producers’ exposure level to pesticides in vegetable production in Burkina Faso, a study was carried out in 2016 and 2017 among 30 tomato producers in the municipalities of Kouka and Toussiana. Eighteen (18 commercial formulations were identified, with more than 50% of pesticides destined for cotton production. Eleven active substances have been identified and the most frequently used are λ-cyhalothrin (35%, acetamiprid (22% and profenofos (13%. The most commonly used chemical families are pyrethroids (28% and organophosphates (18%. The study revealed a low level of training for producers, a high use of pesticides according to the Frequency Treatment Indicator, and a very low level of protection used by producers. The Health Risk Index shows that active substances such as methomyl, λ-cyhalothrin and profenofos present very high risk to operators’ health. Based on the UK-POEM model, the predictive exposure levels obtained varied from 0.0105 mg/kg body weight/day to 1.7855 mg/kg body weight/day, which is several times higher than the Acceptable Operator Exposure Level. However, the study also shows that exposure can be greatly reduced if the required Personal Protective Equipment is worn. Producers’ awareness and training on integrated pest management are necessary to reduce the risks linked to the pesticides use in Burkina Faso.

Estimate of safe human exposure levels for lunar dust based on comparative benchmark dose modeling.

Science.gov (United States)

James, John T; Lam, Chiu-Wing; Santana, Patricia A; Scully, Robert R

2013-04-01

Brief exposures of Apollo astronauts to lunar dust occasionally elicited upper respiratory irritation; however, no limits were ever set for prolonged exposure to lunar dust. The United States and other space faring nations intend to return to the moon for extensive exploration within a few decades. In the meantime, habitats for that exploration, whether mobile or fixed, must be designed to limit human exposure to lunar dust to safe levels. Herein we estimate safe exposure limits for lunar dust collected during the Apollo 14 mission. We instilled three respirable-sized (∼2 μ mass median diameter) lunar dusts (two ground and one unground) and two standard dusts of widely different toxicities (quartz and TiO₂) into the respiratory system of rats. Rats in groups of six were given 0, 1, 2.5 or 7.5 mg of the test dust in a saline-Survanta® vehicle, and biochemical and cellular biomarkers of toxicity in lung lavage fluid were assayed 1 week and one month after instillation. By comparing the dose--response curves of sensitive biomarkers, we estimated safe exposure levels for astronauts and concluded that unground lunar dust and dust ground by two different methods were not toxicologically distinguishable. The safe exposure estimates were 1.3 ± 0.4 mg/m³ (jet-milled dust), 1.0 ± 0.5 mg/m³ (ball-milled dust) and 0.9 ± 0.3 mg/m³ (unground, natural dust). We estimate that 0.5-1 mg/m³ of lunar dust is safe for periodic human exposures during long stays in habitats on the lunar surface.

Levels and source apportionment of children's lead exposure: Could urinary lead be used to identify the levels and sources of children's lead pollution?

International Nuclear Information System (INIS)

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

2015-01-01

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as 207 Pb/ 206 Pb, 208 Pb/ 206 Pb and 204 Pb/ 206 Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. - Highlights: • Pb isotopes of environmental media and children's blood and urine were analyzed. • Pb exposure and pollution source were studied in lead-acid battery and coking areas. • Pb isotope ratios in blood and urine were similar to those of food, water and PM. • Urine Pb level may not be used as a proxy for indicating the lead levels in blood. • Urine Pb isotope ratios is an alternative to identify source and exposure pathways. - Urinary lead is not a preferable proxy to estimate blood lead level, but urinary lead isotope ratios could be an alternative for identifying the sources of lead exposure in children

Tissue distribution of a leukotriene antagonist 14C-LY170680, following inhalation exposure in the rat

International Nuclear Information System (INIS)

Pohland, R.C.; Beck, J.M.; Carlson, K.H.; Herman, D.R.; Hoppes, J.L.; Vavrek, M.T.; Wolff, R.K.

1991-01-01

Dissection and whole-body autoradiographic techniques were used to determine the tissue distribution profile of a leukotriene antagonist, 14 C-LY170680, following nose-only inhalation exposure in the rat. Liquid scintillation spectrometry and whole-body autoradiography indicated that highest concentrations of radiocarbon were present in stomach and small intestine at all time points. Radiocarbon reached maximum levels in stomach (2,259 ng-eq/g) and small intestine (2,399 ng-eq/g) 2 to 4 hours postexposure, respectively, and declined with time. In contrast, maximum radiocarbon concentrations in the head (146 ng-eq/g), trachea (408 ng-eq/g), and lung (534 ng-eq/g) occurred at 0 hours postexposure and steadily declined with time. Low concentrations of radiocarbon were detected in the liver ( 14 C-LY170680 were deposited in the head and within the lung following inhalation exposure. However, higher levels of radiocarbon present in the stomach and small intestine suggested significant nasal deposition followed by rapid clearance and ingestion of inhaled radioactive material. Distribution of radiocarbon limited to the respiratory and gastrointestinal tracts demonstrated minimal systemic absorption and exposure over the time course of this study

Exposure to radio waves near mobile phone base stations

International Nuclear Information System (INIS)

Mann, S.M.; Cooper, T.G.; Allen, S.G.; Blackwell, R.P.; Lowe, A.J.

2000-01-01

Measurements of power density have been made at 17 sites where people were concerned about their exposure to radio waves from mobile phone base stations and where technical data, including the frequencies and radiated powers, have been obtained from the operators. Based on the technical data, the radiated power from antennas used with macrocellular base stations in the UK appears to range from a few watts to a few tens of watts, with typical maximum powers around 80 W. Calculations based on this power indicate that compliance distances would be expected to be no more than 3.1 m for the NRPB guidelines and no more than 8.4 m for the ICNIRP public guidelines. Microcellular base stations appear to use powers no more than a few watts and would not be expected to require compliance distances in excess of a few tens of centimetres. Power density from the base stations of interest was measured at 118 locations at the 17 sites and these data were compared with calculations assuming an inverse square law dependence of power density upon distance from the antennas. It was found that the calculations overestimated the measured power density by up to four orders of magnitude at locations that were either not exposed to the main beam from antennas, or shielded by building fabric. For all locations and for distances up to 250 m from the base stations, power density at the measurement positions did not show any trend to decrease with increasing distance. The signals from other sources were frequently found to be of similar strength to the signals from the base stations of interest. Spectral measurements were obtained over the 30 MHz to 2.9 GHz range at 73 of the locations so that total exposure to radio signals could be assessed. The geometric mean total exposure arising from all radio signals at the locations considered was 2 millionths of the NRPB investigation level, or 18 millionths of the lower ICNIRP public reference level; however, the data varied over several decades. The

Maximum likelihood estimation for cytogenetic dose-response curves

International Nuclear Information System (INIS)

Frome, E.L.; DuFrain, R.J.

1986-01-01

In vitro dose-response curves are used to describe the relation between chromosome aberrations and radiation dose for human lymphocytes. The lymphocytes are exposed to low-LET radiation, and the resulting dicentric chromosome aberrations follow the Poisson distribution. The expected yield depends on both the magnitude and the temporal distribution of the dose. A general dose-response model that describes this relation has been presented by Kellerer and Rossi (1972, Current Topics on Radiation Research Quarterly 8, 85-158; 1978, Radiation Research 75, 471-488) using the theory of dual radiation action. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting dose-time-response models are intrinsically nonlinear in the parameters. A general-purpose maximum likelihood estimation procedure is described, and estimation for the nonlinear models is illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

A Two-Stage Information-Theoretic Approach to Modeling Landscape-Level Attributes and Maximum Recruitment of Chinook Salmon in the Columbia River Basin.

Energy Technology Data Exchange (ETDEWEB)

Thompson, William L.; Lee, Danny C.

2000-11-01

Many anadromous salmonid stocks in the Pacific Northwest are at their lowest recorded levels, which has raised questions regarding their long-term persistence under current conditions. There are a number of factors, such as freshwater spawning and rearing habitat, that could potentially influence their numbers. Therefore, we used the latest advances in information-theoretic methods in a two-stage modeling process to investigate relationships between landscape-level habitat attributes and maximum recruitment of 25 index stocks of chinook salmon (Oncorhynchus tshawytscha) in the Columbia River basin. Our first-stage model selection results indicated that the Ricker-type, stock recruitment model with a constant Ricker a (i.e., recruits-per-spawner at low numbers of fish) across stocks was the only plausible one given these data, which contrasted with previous unpublished findings. Our second-stage results revealed that maximum recruitment of chinook salmon had a strongly negative relationship with percentage of surrounding subwatersheds categorized as predominantly containing U.S. Forest Service and private moderate-high impact managed forest. That is, our model predicted that average maximum recruitment of chinook salmon would decrease by at least 247 fish for every increase of 33% in surrounding subwatersheds categorized as predominantly containing U.S. Forest Service and privately managed forest. Conversely, mean annual air temperature had a positive relationship with salmon maximum recruitment, with an average increase of at least 179 fish for every increase in 2 C mean annual air temperature.

Heat exposure on farmers in northeast Ghana

Science.gov (United States)

Frimpong, Kwasi; Van Etten E J, Eddie; Oosthuzien, Jacques; Fannam Nunfam, Victor

2017-03-01

Environmental health hazards faced by farmers, such as exposure to extreme heat stress, are a growing concern due to global climate change, particularly in tropical developing countries. In such environments, farmers are considered to be a population at risk of environmental heat exposure. The situation is exacerbated due to their farming methods that involve the use of primitive equipment and hard manual labour conducted in full sunshine under hot and humid conditions. However, there is inadequate information about the extent of heat exposure to such farmers, both at the household and farm levels. This paper presents results from a study assessing environmental heat exposure on rural smallholder farmers in Bawku East, Northern Ghana. From January to December 2013, Lascar USB temperature and humidity sensors and a calibrated Questemp heat stress monitor were deployed to farms and homes of rural farmers at Pusiga in Bawku East to capture farmers' exposure to heat stress in both their living and working environments as they executed regular farming routines. The Lascar sensors have the capability to frequently, accurately and securely measure temperature and humidity over long periods. The Questemp heat stress monitor was placed in the same vicinity and showed strong correlations to Lascar sensors in terms of derived values of wet-bulb globe temperature (WBGT). The WBGT in the working environment of farmers peaked at 33.0 to 38.1 °C during the middle of the day in the rainy season from March to October and dropped to 14.0-23.7 °C in the early morning during this season. A maximum hourly WBGT of 28.9-37.5 °C (March-October) was recorded in the living environment of farmers, demonstrating little relief from heat exposure during the day. With these levels of heat stress, exposed farmers conducting physically demanding outdoor work risk suffering serious health consequences. The sustainability of manual farming practices is also under threat by such high levels of

Effects of fasting on maximum thermogenesis in temperature-acclimated rats

Science.gov (United States)

Wang, L. C. H.

1981-09-01

To further investigate the limiting effect of substrates on maximum thermogenesis in acute cold exposure, the present study examined the prevalence of this effect at different thermogenic capabilities consequent to cold- or warm-acclimation. Male Sprague-Dawley rats (n=11) were acclimated to 6, 16 and 26‡C, in succession, their thermogenic capabilities after each acclimation temperature were measured under helium-oxygen (21% oxygen, balance helium) at -10‡C after overnight fasting or feeding. Regardless of feeding conditions, both maximum and total heat production were significantly greater in 6>16>26‡C-acclimated conditions. In the fed state, the total heat production was significantly greater than that in the fasted state at all acclimating temperatures but the maximum thermogenesis was significant greater only in the 6 and 16‡C-acclimated states. The results indicate that the limiting effect of substrates on maximum and total thermogenesis is independent of the magnitude of thermogenic capability, suggesting a substrate-dependent component in restricting the effective expression of existing aerobic metabolic capability even under severe stress.

The timing of the maximum extent of the Rhone Glacier at Wangen a.d. Aare

Energy Technology Data Exchange (ETDEWEB)

Ivy-Ochs, S.; Schluechter, C. [Bern Univ. (Switzerland); Kubik, P.W. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Beer, J. [EAWAG, Duebendorf (Switzerland)

1997-09-01

Erratic blocks found in the region of Wangen a.d. Aare delineate the maximum position of the Solothurn lobe of the Rhone Glacier. {sup 10}Be and {sup 26}Al exposure ages of three of these blocks show that the glacier withdraw from its maximum position at or slightly before 20,000{+-}1800 years ago. (author) 1 fig., 5 refs.

Acute myeloid and chronic lymphoid leukaemias and exposure to low-level benzene among petroleum workers

Science.gov (United States)

Rushton, L; Schnatter, A R; Tang, G; Glass, D C

2014-01-01

Background: High benzene exposure causes acute myeloid leukaemia (AML). Three petroleum case–control studies identified 60 cases (241 matched controls) for AML and 80 cases (345 matched controls) for chronic lymphoid leukaemia (CLL). Methods: Cases were classified and scored regarding uncertainty by two haematologists using available diagnostic information. Blinded quantitative benzene exposure assessment used work histories and exposure measurements adjusted for era-specific circumstances. Statistical analyses included conditional logistic regression and penalised smoothing splines. Results: Benzene exposures were much lower than previous studies. Categorical analyses showed increased ORs for AML with several exposure metrics, although patterns were unclear; neither continuous exposure metrics nor spline analyses gave increased risks. ORs were highest in terminal workers, particularly for Tanker Drivers. No relationship was found between benzene exposure and risk of CLL, although the Australian study showed increased risks in refinery workers. Conclusion: Overall, this study does not persuasively demonstrate a risk between benzene and AML. A previously reported strong relationship between myelodysplastic syndrome (MDS) (potentially previously reported as AML) at our study's low benzene levels suggests that MDS may be the more relevant health risk for lower exposure. Higher CLL risks in refinery workers may be due to more diverse exposures than benzene alone. PMID:24357793

The maximum ground level concentration of air pollutant and the effect of plume rise on concentration estimates

International Nuclear Information System (INIS)

Mayhoub, A.B.; Azzam, A.

1991-01-01

The emission of an air pollutant from an elevated point source according to Gaussian plume model has been presented. An elementary theoretical treatment for both the highest possible ground-level concentration and the downwind distance at which this maximum occurs for different stability classes has been constructed. The effective height release modification was taken into consideration. An illustrative case study, namely, the emission from the research reactor in Inchas, has been studied. The results of these analytical treatments and of the derived semi-empirical formulae are discussed and presented in few illustrative diagrams

Low-level arsenic exposure via drinking water consumption and female fecundity - A preliminary investigation.

Science.gov (United States)

Susko, Michele L; Bloom, Michael S; Neamtiu, Iulia A; Appleton, Allison A; Surdu, Simona; Pop, Cristian; Fitzgerald, Edward F; Anastasiu, Doru; Gurzau, Eugen S

2017-04-01

High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiṣ County, Romania. Women (n=94) with planned pregnancies of 5-20 weeks gestation completed a comprehensive physician-administered study questionnaire and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women. For example, 1µg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P=0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. Copyright © 2016 Elsevier Inc. All rights reserved.

Low level prenatal exposure to methylmercury disrupts neuronal migration in the developing rat cerebral cortex

International Nuclear Information System (INIS)

Guo, Bao-Qiang; Yan, Chong-Huai; Cai, Shi-Zhong; Yuan, Xiao-Bing; Shen, Xiao-Ming

2013-01-01

Highlights: ► Low level MeHg exposure causes migratory defect of rat cerebrocortical neurons. ► The migration defect is due to the impact of MeHg on the neuronal migration itself. ► Rho GTPases seem to be involved in MeHg-induced disruption of neuronal migration. -- Abstract: We determined the effects of low-level prenatal MeHg exposure on neuronal migration in the developing rat cerebral cortex using in utero electroporation. We used offspring rats born to dams that had been exposed to saline or various doses of MeHg (0.01 mg/kg/day, 0.1 mg/kg/day, and 1 mg/kg/day) from gestational day (GD) 11–21. Immunohistochemical examination of the brains of the offspring was conducted on postnatal day (PND) 0, PND3, and PND7. Our results showed that prenatal exposure to low levels of MeHg (0.1 mg/kg/day or 1 mg/kg/day) during the critical stage in neuronal migration resulted in migration defects of the cerebrocortical neurons in offspring rats. Importantly, our data revealed that the abnormal neuronal distribution induced by MeHg was not caused by altered proliferation of neural progenitor cells (NPCs), induction of apoptosis of NPCs and/or newborn neurons, abnormal differentiation of NPCs, and the morphological changes of radial glial scaffold, indicating that the defective neuronal positioning triggered by exposure to low-dose of MeHg is due to the impacts of MeHg on the process of neuronal migration itself. Moreover, we demonstrated that in utero exposure to low-level MeHg suppresses the expression of Rac1, Cdc42, and RhoA, which play key roles in the migration of cerebrocortical neurons during the early stage of brain development, suggesting that the MeHg-induced migratory disturbance of cerebrocortical neurons is likely associated with the Rho GTPases signal pathway. In conclusion, our results provide a novel perspective on clarifying the mechanisms underlying the impairment of neuronal migration induced by MeHg

Prenatal androgen exposure and children's aggressive behavior and activity level.

Science.gov (United States)

Spencer, Debra; Pasterski, Vickie; Neufeld, Sharon; Glover, Vivette; O'Connor, Thomas G; Hindmarsh, Peter C; Hughes, Ieuan A; Acerini, Carlo L; Hines, Melissa

2017-11-01

Some human behaviors, including aggression and activity level, differ on average for males and females. Here we report findings from two studies investigating possible relations between prenatal androgen and children's aggression and activity level. For study 1, aggression and activity level scores for 43 girls and 38 boys, aged 4 to 11years, with congenital adrenal hyperplasia (CAH, a genetic condition causing increased adrenal androgen production beginning prenatally) were compared to those of similarly-aged, unaffected relatives (41 girls, 31 boys). Girls with CAH scored higher on aggression than unaffected girls, d=0.69, and unaffected boys scored higher on activity level than unaffected girls, d=0.50. No other group differences were significant. For study 2, the relationship of amniotic fluid testosterone to aggression and activity level was investigated in typically-developing children (48 girls, 44 boys), aged 3 to 5years. Boys scored higher than girls on aggression, d=0.41, and activity level, d=0.50. However, amniotic fluid testosterone was not a significant predictor of aggression or activity level for either sex. The results of the two studies provide some support for an influence of prenatal androgen exposure on children's aggressive behavior, but not activity level. The within-sex variation in amniotic fluid testosterone may not be sufficient to allow reliable assessment of relations to aggression or activity level. Copyright © 2017 Elsevier Inc. All rights reserved.

Effects of low-level sarin and cyclosarin exposure on hippocampal subfields in Gulf War Veterans.

Science.gov (United States)

Chao, Linda L; Kriger, Stephen; Buckley, Shannon; Ng, Peter; Mueller, Susanne G

2014-09-01

More than 100,000 US troops were potentially exposed to chemical warfare agents sarin (GB) and cyclosarin (GF) when an ammunition dump at Khamisiyah, Iraq was destroyed during the 1991 Gulf War (GW). We previously reported reduced hippocampal volume in GW veterans with suspected GB/GF exposure relative to matched, unexposed GW veterans estimated from 1.5T magnetic resonance images (MRI). Here we investigate, in a different cohort of GW veterans, whether low-level GB/GF exposure is associated with structural alterations in specific hippocampal subfields, estimated from 4T MRI. The Automatic Segmentation of Hippocampal Subfields (ASHS) technique was used to quantify CA1, CA2, CA3 and dentate gyrus (DG), and subiculum (SUB) subfields volumes from high-resolution T2-weighted images acquired on a 4T MR scanner in 56 GW veterans with suspected GB/GF exposure and 56 "matched" unexposed GW veterans (mean age 49±7 years). GB/GF exposed veterans had smaller CA2 (p=0.003) and CA3/DG (p=0.01) subfield volumes compared to matched, unexposed GW veterans. There were no group difference in total hippocampal volume, quantified with FreeSurfer, and no dose-response relationship between estimated levels of GB/GF exposure and total hippocampal or subfield volume. These findings extend our previous report of structural alterations in the hippocampi of GW veterans with suspected GB/GF exposure to volume changes in the CA2, CA3, and DG hippocampal subfields in a different cohort of GW veterans with suspected GB/GF exposure. Published by Elsevier B.V.

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

International Nuclear Information System (INIS)

Halton, D.M.

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC LO , LC 10 and LC 50 levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs

Toxicity levels to humans during acute exposure to hydrogen fluoride - An update

Energy Technology Data Exchange (ETDEWEB)

Halton, D M

1995-09-01

In March 1993, the Atomic Energy Control Board (AECB) commissioned and update of a 1984 review on the acute toxicity of hydrogen fluoride (HF). The study places particular emphasis on the effects of inhalation of gaseous HF and is divided into two main parts: a literature review and a lethal concentration (LC) estimation. The literature review summarizes data under four categories: animal studies, controlled human studies, community exposure, and industrial exposure. Data in these areas were critically reviewed for their relevance to lethal concentrations at LC{sub LO}, LC{sub 10} and LC{sub 50} levels that were derived in the 1984 report. In the last ten years, only one relevant animal study has been published. No new controlled human studies were found but a community exposure incident was reported. There were three new industrial/accidental exposures reported since 1984. Evaluation of new data does not change the lethal concentration estimates made in the 1984 report, but does indicate the absence of appropriate models to estimate the lethality of irritant and corrosive gases. In the last 10 years, much literature on the evaluation of major hazards has been published and suggests that such assessments are of growing political, economic and social importance. Numerous articles have been published on the acute toxicity of HF from skin contact and chronic toxicity from repeated airborne exposure. These publications offer important insights into the nature of HF toxicity. Several avenues of investigative research are suggested. (author). 55 refs., 4 tabs.

Low-level arsenic exposure via drinking water consumption and female fecundity - A preliminary investigation

Energy Technology Data Exchange (ETDEWEB)

Susko, Michele L. [Department of Epidemiology and Biostatistics, University at Albany, State University of New York, Rensselaer, New York (United States); Bloom, Michael S., E-mail: mbloom@albany.edu [Department of Epidemiology and Biostatistics, University at Albany, State University of New York, Rensselaer, New York (United States); Department of Environmental Health Sciences, University at Albany, State University of New York, Rensselaer, New York (United States); Neamtiu, Iulia A. [Health Department, Environmental Health Center, Cluj-Napoca (Romania); IMOGEN Research Institute, Cluj-Napoca (Romania); Appleton, Allison A. [Department of Epidemiology and Biostatistics, University at Albany, State University of New York, Rensselaer, New York (United States); Surdu, Simona [Department of Environmental Health Sciences, University at Albany, State University of New York, Rensselaer, New York (United States); Pop, Cristian [Physico-chemical and Biotoxicological Analysis Laboratory, Environmental Health Center, Cluj-Napoca (Romania); Cluj School of Public Health - College of Political, Administrative and Communication Sciences, Babeș-Bolyai University, Cluj-Napoca (Romania); Faculty of Environmental Science and Engineering, Babeș-Bolyai University, Cluj-Napoca (Romania); Fitzgerald, Edward F. [Department of Epidemiology and Biostatistics, University at Albany, State University of New York, Rensselaer, New York (United States); Department of Environmental Health Sciences, University at Albany, State University of New York, Rensselaer, New York (United States); Anastasiu, Doru [University of Medicine and Pharmacy “Victor Babeș”, Timișoara (Romania); Obstetrics and Gynecology Department of the Emergency County Hospital, Timișoara (Romania); and others

2017-04-15

High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiá¹£ County, Romania. Women (n=94) with planned pregnancies of 5–20 weeks gestation completed a comprehensive physician-administered study questionnaire and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women. For example, 1 µg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P=0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. - Highlights: • We assessed low level drinking water arsenic as a predictor of fecundability. • Arsenic did

Low-level arsenic exposure via drinking water consumption and female fecundity - A preliminary investigation

International Nuclear Information System (INIS)

Susko, Michele L.; Bloom, Michael S.; Neamtiu, Iulia A.; Appleton, Allison A.; Surdu, Simona; Pop, Cristian; Fitzgerald, Edward F.; Anastasiu, Doru

2017-01-01

High level arsenic exposure is associated with reproductive toxicity in experimental and observational studies; however, few data exist to assess risks at low levels. Even less data are available to evaluate the impact of low level arsenic exposure on human fecundity. Our aim in this pilot study was a preliminary evaluation of associations between low level drinking water arsenic contamination and female fecundity. This retrospective study was conducted among women previously recruited to a hospital-based case-control study of spontaneous pregnancy loss in Timiá¹£ County, Romania. Women (n=94) with planned pregnancies of 5–20 weeks gestation completed a comprehensive physician-administered study questionnaire and reported the number of menstrual cycles attempting to conceive as the time to pregnancy (TTP). Drinking water samples were collected from residential drinking water sources and we determined arsenic levels using hydride generation-atomic absorption spectrometry (HG-AAS). Multivariable Cox-proportional hazards regression with Efron approximation was employed to evaluate TTP as a function of drinking water arsenic concentrations among planned pregnancies, adjusted for covariates. There was no main effect for drinking water arsenic exposure, yet the conditional probability for pregnancy was modestly lower among arsenic exposed women with longer TTPs, relative to women with shorter TTPs, and relative to unexposed women. For example, 1 µg/L average drinking water arsenic conferred 5%, 8%, and 10% lower likelihoods for pregnancy in the 6th, 9th, and 12th cycles, respectively (P=0.01). While preliminary, our results suggest that low level arsenic contamination in residential drinking water sources may further impair fecundity among women with longer waiting times; however, this hypothesis requires confirmation by a future, more definitive study. - Highlights: • We assessed low level drinking water arsenic as a predictor of fecundability. • Arsenic did

Radiographic apparatus and method for monitoring film exposure time

International Nuclear Information System (INIS)

Vatne, R.S.; Woodmansee, W.E.

1981-01-01

In connection with radiographic inspection of structural and industrial materials, method and apparatus are disclosed for automatically determining and displaying the time required to expose a radiographic film positioned to receive radiation passed by a test specimen, so that the finished film is exposed to an optimum blackening (density) for maximum film contrast. A plot is made of the variations in a total exposure parameter (representing the product of detected radiation rate and time needed to cause optimum film blackening) as a function of the voltage level applied to an X-ray tube. An electronic function generator storing the shape of this plot is incorporated into an exposure monitoring apparatus, such that for a selected tube voltage setting, the function generator produces an electrical analog signal of the corresponding exposure parameter. During the exposure, another signal is produced representing the rate of radiation as monitored by a diode detector positioned so as to receive the same radiation that is incident on the film. The signal representing the detected radiation rate is divided, by an electrical divider circuit into the signal representing total exposure, and the resulting quotient is an electrical signal representing the required exposure time. (author)

Association of dental enamel lead levels with risk factors for environmental exposure.

Science.gov (United States)

Olympio, Kelly Polido Kaneshiro; Naozuka, Juliana; Oliveira, Pedro Vitoriano; Cardoso, Maria Regina Alves; Bechara, Etelvino José Henriques; Günther, Wanda Maria Risso

2010-10-01

To analyze household risk factors associated with high lead levels in surface dental enamel. A cross-sectional study was conducted with 160 Brazilian adolescents aged 1418 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old) exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97); and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00). Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03) and smoking (OR = 1.66; 95% CI: 0.52;5.28) were not found to be associated with high dental enamel lead levels. Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Investigation on the acceptance level of radiation exposure. Comparison of Chinese and Japanese

International Nuclear Information System (INIS)

Wu, Jin; Katoh, Kazuaki

1999-01-01

Radiation has helped to develop our culture and civilization, both of material and of spiritual, and without doubt it is useful to develop our civilization further and to enrich our future life. On the other hand, we cannot help avoiding to live with some by-product radiation of 'advanced civilization' in addition. Thus we must associate with radiation even if we like it or not. To our understanding, safety standard or criteria of safety control is nothing but a contract of the body concerned with the society. In order to make this contract rigorously, it is required for both sides to have adequately enough knowledge and data on the methodology of treating the matter. In such societies, people's acceptable levels to radiation exposure would not be widely distributed. Unification of the wills of the society is absolutely necessary to establish such a contact or develop the philosophy on radiation safety. Hence, we have tried to investigate the acceptable levels of people to radiation exposure. Two kinds of levels, upper limit of the acceptable dose for instantaneous whole body exposure, Lu, and lowest of the dose caring in mind, Ll, were set for inquiry. In this presentation, some results of our survey to both Chinese and Japanese professionals in the fields of science-technology and medical science are reported. Similarly to the previous study by Katoh, in 1989 or so, the distribution of these two levels were very broad and the band widths between the two levels, Lu and Ll, were quite narrow. The former seems reveal the variety of individual's sense of value. Moreover, it was found that, two levels, Lu and Ll, were significantly higher (p<0.05, p<0.005) in Japanese to in Chinese in science/engineering group, while in medical group, the two levels were higher apparently in Japanese than in Chinese, but no statistically significant difference was observed. Moreover, in medical group, Lu and Ll showed higher values than those in science-technology group for the

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

Directory of Open Access Journals (Sweden)

Lai Dejian

2011-03-01

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

Commuter exposure to inhalable, thoracic and alveolic particles in various transportation modes in Delhi.

Science.gov (United States)

Kumar, Pramod; Gupta, N C

2016-01-15

A public health concern is to understand the linkages between specific pollution sources and adverse health impacts. Commuting can be viewed as one of the significant-exposure activity in high-vehicle density areas. This paper investigates the commuter exposure to inhalable, thoracic and alveolic particles in various transportation modes in Delhi, India. Air pollution levels are significantly contributed by automobile exhaust and also in-vehicle exposure can be higher sometime than ambient levels. Motorcycle, auto rickshaw, car and bus were selected to study particles concentration along two routes in Delhi between Kashmere Gate and Dwarka. The bus and auto rickshaw were running on compressed natural gas (CNG) while the car and motorcycle were operated on gasoline fuel. Aerosol spectrometer was employed to measure inhalable, thoracic and alveolic particles during morning and evening rush hours for five weekdays. From the study, we observed that the concentration levels of these particles were greatly influenced by transportation modes. Concentrations of inhalable particles were found higher during morning in auto rickshaw (332.81 ± 90.97 μg/m(3)) while the commuter of bus exhibited higher exposure of thoracic particles (292.23 ± 110.45 μg/m(3)) and car commuters were exposed to maximum concentrations of alveolic particles (222.37 ± 26.56 μg/m(3)). We observed that in evening car commuters experienced maximum concentrations of all sizes of particles among the four commuting modes. Interestingly, motorcycle commuters were exposed to lower levels of inhalable and thoracic particles during morning and evening hours as compared to other modes of transport. The mean values were found greater than the median values for all the modes of transport suggesting that positive skewed distributions are characteristics of naturally occurring phenomenon. Copyright © 2015 Elsevier B.V. All rights reserved.

Sensitivity of ecological soil-screening levels for metals to exposure model parameterization and toxicity reference values.

Science.gov (United States)

Sample, Bradley E; Fairbrother, Anne; Kaiser, Ashley; Law, Sheryl; Adams, Bill

2014-10-01

Ecological soil-screening levels (Eco-SSLs) were developed by the United States Environmental Protection Agency (USEPA) for the purposes of setting conservative soil screening values that can be used to eliminate the need for further ecological assessment for specific analytes at a given site. Ecological soil-screening levels for wildlife represent a simplified dietary exposure model solved in terms of soil concentrations to produce exposure equal to a no-observed-adverse-effect toxicity reference value (TRV). Sensitivity analyses were performed for 6 avian and mammalian model species, and 16 metals/metalloids for which Eco-SSLs have been developed. The relative influence of model parameters was expressed as the absolute value of the range of variation observed in the resulting soil concentration when exposure is equal to the TRV. Rank analysis of variance was used to identify parameters with greatest influence on model output. For both birds and mammals, soil ingestion displayed the broadest overall range (variability), although TRVs consistently had the greatest influence on calculated soil concentrations; bioavailability in food was consistently the least influential parameter, although an important site-specific variable. Relative importance of parameters differed by trophic group. Soil ingestion ranked 2nd for carnivores and herbivores, but was 4th for invertivores. Different patterns were exhibited, depending on which parameter, trophic group, and analyte combination was considered. The approach for TRV selection was also examined in detail, with Cu as the representative analyte. The underlying assumption that generic body-weight-normalized TRVs can be used to derive protective levels for any species is not supported by the data. Whereas the use of site-, species-, and analyte-specific exposure parameters is recommended to reduce variation in exposure estimates (soil protection level), improvement of TRVs is more problematic. © 2014 The Authors

Medium wave exposure characterisation using exposure quotients.

Science.gov (United States)

Paniagua, Jesús M; Rufo, Montaña; Jiménez, Antonio; Antolín, Alicia; Pinar, Iván

2010-06-01

One of the aspects considered in the International Commission on Non-Ionizing Radiation Protection guidelines is that, in situations of simultaneous exposure to fields of different frequencies, exposure quotients for thermal and electrical stimulation effects should be examined. The aim of the present work was to analyse the electromagnetic radiation levels and exposure quotients for exposure to multiple-frequency sources in the vicinity of medium wave radio broadcasting antennas. The measurements were made with a spectrum analyser and a monopole antenna. Kriging interpolation was used to prepare contour maps and to estimate the levels in the towns and villages of the zone. The results showed that the exposure quotient criterion based on electrical stimulation effects to be more stringent than those based on thermal effects or power density levels. Improvement of dosimetry evaluations requires the spectral components of the radiation to be quantified, followed by application of the criteria for exposure to multiple-frequency sources.

Minimum and Maximum Potential Contributions to Future Sea Level Rise from Polar Ice Sheets

Science.gov (United States)

Deconto, R. M.; Pollard, D.

2017-12-01

New climate and ice-sheet modeling, calibrated to past changes in sea-level, is painting a stark picture of the future fate of the great polar ice sheets if greenhouse gas emissions continue unabated. This is especially true for Antarctica, where a substantial fraction of the ice sheet rests on bedrock more than 500-meters below sea level. Here, we explore the sensitivity of the polar ice sheets to a warming atmosphere and ocean under a range of future greenhouse gas emissions scenarios. The ice sheet-climate-ocean model used here considers time-evolving changes in surface mass balance and sub-ice oceanic melting, ice deformation, grounding line retreat on reverse-sloped bedrock (Marine Ice Sheet Instability), and newly added processes including hydrofracturing of ice shelves in response to surface meltwater and rain, and structural collapse of thick, marine-terminating ice margins with tall ice-cliff faces (Marine Ice Cliff Instability). The simulations improve on previous work by using 1) improved atmospheric forcing from a Regional Climate Model and 2) a much wider range of model physical parameters within the bounds of modern observations of ice dynamical processes (particularly calving rates) and paleo constraints on past ice-sheet response to warming. Approaches to more precisely define the climatic thresholds capable of triggering rapid and potentially irreversible ice-sheet retreat are also discussed, as is the potential for aggressive mitigation strategies like those discussed at the 2015 Paris Climate Conference (COP21) to substantially reduce the risk of extreme sea-level rise. These results, including physics that consider both ice deformation (creep) and calving (mechanical failure of marine terminating ice) expand on previously estimated limits of maximum rates of future sea level rise based solely on kinematic constraints of glacier flow. At the high end, the new results show the potential for more than 2m of global mean sea level rise by 2100

Design of exposure systems for ELF electric field bioeffects research

International Nuclear Information System (INIS)

Kaune, W.T.; Decker, J.R.; Phillips, R.D.; Gillis, M.F.

1978-01-01

Two systems for exposure and sham-exposure of large numbers of rats and mice to uniform, vertical, 60-Hz electric fields have been constructed. The rat system contains four racks of four rectangular 1.0m x 2.2m exposure-electrodes that are stacked vertically with a separation between adjacent electrodes of 0.41 m. Any two of the four exposure racks may be energized to a maximum field strength of 150 kV/m. Each exposure electrode is equipped with 24 Lexan cages, each of which holds a single rat. The cage floor is a stainless steel screen that serves as one electrode. The system for watering animals is contained entirely within the electrode and does not protrude above the cage's floor, thereby preventing distortion of the exposure field and electrical shock or discharge as the animal drinks. The total capacity of the system is 288 rats. A similar system of two racks of five electrodes each is used to expose as many as 450 mice to fields at a maximum strength of 150 kV/m while sham exposing an equal number. Measurements of the electric field reveal an overall uniformity within 4% over the area to be occupied by experimental animals. The field inside a Lexan cage is reduced by about 3%. No corona-discharge has been detected. Measurements of ozone concentration in the rat and mouse exposure systems show no difference from background levels. Harmonic distortion has been eliminated by damping and filtering the high-voltage supply. Animals housed in close proximity are partially shielded from the electric field; the total body current in a rat model is reduced by 35 ± 5% when rats are placed in adjacent cages. (author)

Secondhand smoke exposure levels in outdoor hospitality venues: a qualitative and quantitative review of the research literature.

Science.gov (United States)

Licht, Andrea S; Hyland, Andrew; Travers, Mark J; Chapman, Simon

2013-05-01

This paper considers the evidence on whether outdoor secondhand smoke (SHS) is present in hospitality venues at high levels enough to potentially pose health risks, particularly among employees. Searches 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. Sixteen studies were selected that reported measuring any outdoor SHS exposures (particulate matter (PM) or other SHS indicators). The SHS measurement methods were assessed for inclusion of extraneous variables that may affect levels or the corroboration of measurements with known standards. The magnitude of SHS exposure (PM2.5) depends on the number of smokers present, measurement proximity, outdoor enclosures, and wind. 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. Although highly transitory, outdoor SHS exposures could occasionally exceed annual ambient air quality exposure guidelines. Personal monitoring studies of waitstaff are warranted to corroborate these modeled estimates.

Natural radiation external exposures levels in Chilean Sub-Antarctic and country stations

International Nuclear Information System (INIS)

Stuardo, E.

1988-01-01

Since 1983 gamma exposures levels, at 1,5 m above the soil are being investigated using TLD detectors. A network of 12 stations have been established from ARICA (18 deg 20' S latitude) in Northern Chile to YELCHO (64 deg 52' S latitude) in Antartic territory. One year monitoring period was used at Antartic stations and a four months period in the country. The main subject of this study is to assess the average background radiation levels along the territory which is relevant to get a reference level and specially an estimate of the average natural radiation contribution to the population dose in Southern Chile

Low Level Exposure to GB Vapor in Air: Diagnosis/Dosimetry, Lowest Observable Effect Levels, Performance-Incapacitation, and Possible Delayed Effects

National Research Council Canada - National Science Library

Helden, Herman

2002-01-01

.... 2001 under experimental conditions similar to those in Nov. 2000 when they were first 5 h exposed to air followed by 5 h exposure to low levels of GB vapor in air in a concentration range of 7.5 - 150 micron/m3...

Increased levels of 8-hydroxy-2′-deoxyguanosine are attributable to organophosphate pesticide exposure among young children

International Nuclear Information System (INIS)

Ding Guodong; Han Song; Wang, Pei; Gao Yu; Shi Rong; Wang, Guoquan; Tian Ying

2012-01-01

Oxidative damage has been proposed as an important mechanism linking pesticide exposure to health effects. A study of 268 young Shanghai children was conducted to examine the relationship between organophosphate pesticide (OP) exposure and a biomarker of oxidative DNA damage. Urine samples were analyzed for five nonspecific dialkyl phosphate (DAP) metabolites [dimethyl phosphates (DMs) and diethyl phosphates (DEs)] and 8-hydroxy-2′-deoxyguanosine (8-OHdG). The creatinine-adjusted median of 8-OHdG in urine samples was 3.99 ng/mg. Increased exposure to OPs was associated with greater levels of urinary 8-OHdG [total DAPs: ß (adjusted) = 0.46 per log 10 unit increase, 95% confidence interval (CI) = 0.40–0.53, p = 0.000; DMs: ß (adjusted) = 0.34, 95% CI = 0.28–0.41, p = 0.000; DEs: ß (adjusted) = 0.48, 95% CI = 0.42–0.54, p = 0.000]. Thus, the 8-OHdG biomarker is useful for increasing our understanding of the link between childhood exposure to OPs and health outcomes. - Highlights: ► OP exposures are thought to affect health by mechanisms related to oxidative stress. ► We assessed the correlation between OP exposure and a biomarker of oxidative stress. ► Increased exposure to OPs was associated with greater levels of urinary 8-OHdG. - Environmental exposure to OPs may play an important role in oxidative DNA damage in children.

Chronic Ethanol Exposure Effects on Vitamin D Levels among Subjects with Alcohol Use Disorder

Directory of Open Access Journals (Sweden)

Olalekan Ogunsakin

2016-01-01

Full Text Available Vitamin D has been previously recognized to play important roles in human immune system and function. In the pulmonary system, vitamin D regulates the function of antimicrobial peptides, especially cathelicidin/LL-37. Human cathelicidin/LL-37 is a bactericidal, bacteriostatic, and antiviral endogenous peptide with protective immune functions. Chronic exposure to excessive alcohol has the potential to reduce levels of vitamin D (inactive vitamin D [25(OHD 3 ] and active vitamin D [1, 25(OH 2 D 3 ] and leads to downregulation of cathelicidin/LL-37. Alcohol-mediated reduction of LL-37 may be partly responsible for increased incidence of more frequent and severe respiratory infections among subjects with alcohol use disorder (AUD. The objective of this study was to investigate the mechanisms by which alcohol exerts its influence on vitamin D metabolism. In addition, the aim was to establish associations between chronic alcohol exposures, levels of pulmonary vitamin D, and cathelicidin/LL-37 using broncho-alveolar lavage fluid samples of subjects with AUD and healthy controls. Findings from the experiment showed that levels of inactive vitamin D (25(OHD 3 , active vitamin D (1, 25(OH 2 D 3 , cathelicidin/LL-37, and CYP27B1 proteins were significantly reduced ( P < 0.05 when compared with the matched healthy control group. However, CYP2E1 was elevated in all the samples examined. Chronic exposure to alcohol has the potential to reduce the levels of pulmonary vitamin D and results in subsequent downregulation of the antimicrobial peptide, LL-37, in the human pulmonary system.

Ground-level ozone pollution and its health impacts in China

Science.gov (United States)

Liu, Huan; Liu, Shuai; Xue, Boru; Lv, Zhaofeng; Meng, Zhihang; Yang, Xiaofan; Xue, Tao; Yu, Qiao; He, Kebin

2018-01-01

In recent years, ground-level ozone pollution in China has become an increasingly prominent problem. This study simulated and analyzed spatiotemporal distribution of ozone and exposure level by the Weather Research and Forecasting (WRF)-Community Multiscale Air Quality (CMAQ) models and monitoring data from 1516 national air quality monitoring stations in China during 2015. The simulation results show that the Sichuan Basin, Shandong, Shanxi, Henan, Anhui, Qinghai-Tibetan Plateau, Yangtze River Delta (YRD), Pearl River Delta (PRD) and Beijing-Tianjin-Hebei (BTH) region had relatively high average annual concentrations of ozone. The regions with more than 10% nonattainment days of 160 μg/m3 (daily maximum 8-h) are mainly concentrated in BTH, Shandong Peninsula and YRD, where large seasonal variations were also found. Exposure levels were calculated based on population data and simulated ozone concentrations. The cumulative population exposed to daily maximum 8-h concentration greater than or equal to 100 μg/m3 was 816.04 million, 61.17% of the total. Three methods were used to estimate the mortality of chronic obstructive pulmonary disease (COPD) attributable to ozone. A comparative study using different exposure concentrations and threshold concentrations found large variations among these methods, although they were all peer-reviewed methods. The estimated mortality of COPD caused by ozone in China in 2015 ranged from 55341 to 80280, which mainly distributed in Beijing, Shandong, Henan, Hubei and Sichuan Province, the YRD and PRD region.

Asbestos exposure of building maintenance personnel.

Science.gov (United States)

Mlynarek, S; Corn, M; Blake, C

1996-06-01

The exposures of building maintenance personnel and occupants to airborne asbestos fibers, and the effects of operations and maintenance programs on those exposures, continue to be an important public health issue. The subject of this investigation was a large metropolitan county with numerous public buildings which routinely conducted air sampling for asbestos. A total of 302 personal air samples in nine task categories collected during maintenance worker activities in proximity to asbestos-containing materials were analyzed; 102 environmental air samples in four task categories were also analyzed. The arithmetic means of the 8-hr time weighted average exposures for personal sampling for each task category were all below the Occupational Safety and Health Administration permissible exposure level of 0.1 fibers (f)/cc > 5 microm. The highest mean 8-hr time weighted average exposure was 0.030 f/cc > 5 microm for ceiling tile replacement. The maximum asbestos concentration during sample collection for environmental samples was 0.027 f/cc > 5 microm. All asbestos-related maintenance work was done within the framework of an Operations and Maintenance Program (OMP) which utilized both personal protective equipment and controls against fiber release/dispersion. Results are presented in association with specific OMP procedures or controls. These results support the effectiveness of using Operations and Maintenance Programs to manage asbestos in buildings without incurring unacceptable risk to maintenance workers performing maintenance tasks.

[Effects of intermittent hypoxic exposure on the parameter of erythrocyte and serum hypoxia inducible factor-1 alpha and erythropoietin levels].

Science.gov (United States)

Zhang, Cheng-yan; Zhang, Ji-xin; Lü, Xiao-tao; Li, Bao-yu

2009-10-01

To investigate the effects of intermittent hypoxic exposure and normoxic convalescence on the parameter of erythrocyte and serum hypoxia inducible factor-1 alpha (HIF-1alpha) and erythropoietin (EPO) levels. Rat models of intermittent hypoxic exposure were established, combined with the clinical research on volunteers experiencing the intermittent plateau work. Blood samples for red blood cell (RBC) counts, hemoglobin (Hb) and hematocrit (HCT) were collected, serum HIF-1alpha and EPO levels were measured using enzyme linked immunosorbent assay. RBC counts, Hb concentration and HCT were significantly higher than the normoxic group (P hypoxic exposure can enhance serum hypoxia inducible factor-1 alpha and erythropointin levels and the generation of red blood cells, which leads to an increase in hemoglobin concentration and hematocrit. The results have changed with the hypoxic exposure period prolonged. Normoxic convalescence after intermittent hypoxic exposure can make the related indexes reduced, and contribute to the organism recovery.

Exposure to hazardous substances in Cathode Ray Tube (CRT) recycling sites in France

Energy Technology Data Exchange (ETDEWEB)

Lecler, Marie-Thérèse, E-mail: marie-therese.lecler@inrs.fr; Zimmermann, François; Silvente, Eric; Clerc, Frédéric; Chollot, Alain; Grosjean, Jérôme

2015-05-15

Highlights: • Chemical risks were assessed in the nine cathode ray tube screens recycling facilities. • The main hazardous agents are dust containing lead, cadmium, barium and yttrium. • Exposure and pollutant levels are described for different operations and processes. • All the operations and processes are concerned by significant levels of pollutants. • We suggest recommendations to reduce chemical risk. - Abstract: The Waste Electrical and Electronic Equipment (WEEE) or e-waste recycling sector has grown considerably in the last fifteen years due to the ever shorter life cycles of consumables and an increasingly restrictive policy context. Cathode Ray Tubes (CRTs) from used television and computer screens represent one of the main sources of e-waste. CRTs contain toxic materials such as lead, cadmium, barium, and fluorescent powders which can be released if recycling of CRTs is not appropriate. Exposure to these harmful substances was assessed in nine workshops where CRT screens are treated. Particulate exposure levels were measured using a gravimetric method and metals were analysed by plasma emission spectrometry. The maximum levels of worker exposure were 8.8 mg/m{sup 3}, 1504.3 μg/m{sup 3}, 434.9 μg/m{sup 3}, 576.3 μg/m{sup 3} and 2894.3 μg/m{sup 3} respectively for inhalable dust, barium, cadmium, lead and yttrium. The maximum levels of airborne pollutants in static samples were 39.0 mg/m{sup 3}, 848.2 μg/m{sup 3}, 698.4 μg/m{sup 3}, 549.3 μg/m{sup 3} and 3437.9 μg/m{sup 3} for inhalable dust, barium, cadmium, lead and yttrium. The most harmful operations were identified, and preventive measures for reducing the chemical risk associated with screen recycling were proposed. Workplace measurements were used to define recommendations for reducing the chemical risks in CRT screens recycling facilities and for promoting the design and development of “clean and safe” processes in emerging recycling channels.

Soil and Water Assessment Tool model predictions of annual maximum pesticide concentrations in high vulnerability watersheds.

Science.gov (United States)

Winchell, Michael F; Peranginangin, Natalia; Srinivasan, Raghavan; Chen, Wenlin

2018-05-01

Recent national regulatory assessments of potential pesticide exposure of threatened and endangered species in aquatic habitats have led to increased need for watershed-scale predictions of pesticide concentrations in flowing water bodies. This study was conducted to assess the ability of the uncalibrated Soil and Water Assessment Tool (SWAT) to predict annual maximum pesticide concentrations in the flowing water bodies of highly vulnerable small- to medium-sized watersheds. The SWAT was applied to 27 watersheds, largely within the midwest corn belt of the United States, ranging from 20 to 386 km 2 , and evaluated using consistent input data sets and an uncalibrated parameterization approach. The watersheds were selected from the Atrazine Ecological Exposure Monitoring Program and the Heidelberg Tributary Loading Program, both of which contain high temporal resolution atrazine sampling data from watersheds with exceptionally high vulnerability to atrazine exposure. The model performance was assessed based upon predictions of annual maximum atrazine concentrations in 1-d and 60-d durations, predictions critical in pesticide-threatened and endangered species risk assessments when evaluating potential acute and chronic exposure to aquatic organisms. The simulation results showed that for nearly half of the watersheds simulated, the uncalibrated SWAT model was able to predict annual maximum pesticide concentrations within a narrow range of uncertainty resulting from atrazine application timing patterns. An uncalibrated model's predictive performance is essential for the assessment of pesticide exposure in flowing water bodies, the majority of which have insufficient monitoring data for direct calibration, even in data-rich countries. In situations in which SWAT over- or underpredicted the annual maximum concentrations, the magnitude of the over- or underprediction was commonly less than a factor of 2, indicating that the model and uncalibrated parameterization

Low-level radiation: a review of current estimates of hazards to human populations

International Nuclear Information System (INIS)

Myers, D.K.

1977-12-01

Mankind has always lived with low levels of ionizing radiation from natural sources. This ionizing radiation may induce cancers in irradiated persons and genetic defects in the descendents of irradiated persons. The internationally accepted estimates of risks suggest that the numbers of cancers and genetic defects induced in the general population by natural background radiation are not more than about 1% of the numbers of cancers and genetic defects normally present in the general population. The added risks to the general public due to any prospective nuclear power program are minute compared to those from background radiation. At the maximum permissible levels of radiation exposures for occupational workers, the predicted number of fatal cancers induced would lead to a reduction in average life-span from 73.0 years to about 72.7 years. Since occupational exposures are usually much less than maximum permissible levels, the risks are correspondingly reduced. These occupational risks are comparable to those in most other industries and occupations. Some areas of uncertainty in the accepted risk estimates are discussed in detail in this review. (author)

Recommendation of maximum allowable noise levels for offshore wind power systems; Empfehlung von Laermschutzwerten bei der Errichtung von Offshore-Windenergieanlagen (OWEA)

Energy Technology Data Exchange (ETDEWEB)

Werner, Stefanie [Umweltbundesamt, Dessau-Rosslau (Germany). Fachgebiet II 2.3

2011-05-15

When offshore wind farms are constructed, every single pile is hammered into the sediment by a hydraulic hammer. Noise levels at Horns Reef wind farm were in the range of 235 dB. The noise may cause damage to the auditory system of marine mammals. The Federal Environmental Office therefore recommends the definition of maximum permissible noise levels. Further, care should be taken that no marine mammals are found in the immediate vicinity of the construction site. (AKB)

Particle Swarm Optimization Based of the Maximum Photovoltaic ...

African Journals Online (AJOL)

Photovoltaic electricity is seen as an important source of renewable energy. The photovoltaic array is an unstable source of power since the peak power point depends on the temperature and the irradiation level. A maximum peak power point tracking is then necessary for maximum efficiency. In this work, a Particle Swarm ...

Last Glacial Maximum and Lateglacial in the Polish High Tatra Mountains - Revised deglaciation chronology based on the 10Be exposure age dating

Science.gov (United States)

Makos, Michał; Rinterknecht, Vincent; Braucher, Régis; Tołoczko-Pasek, Anna; Arnold, Maurice; Aumaître, Georges; Bourlès, Didier; Keddadouche, Karim; Aster Team

2018-05-01

Deglaciation chronology of the Polish High Tatra Mountains has been reconstructed based on 10Be exposure age dating. Fifty-seven rock samples were collected from boulders located on the terminal and lateral moraines that limit the horizontal extent of the LGM and the Lateglacial glaciers in the Biała Woda and Sucha Woda catchments. The uncertainty-weighted mean age of 21.5 ± 2.5 ka obtained for the maximum terminal moraine in the Sucha Woda Valley indicates that the oldest preserved moraines were formed during the global LGM. The age population ranges between 15.1 ± 1.0 and 28.3 ± 2.0 ka, and suggests that glaciers reached their maximum position (LGM I) as early as 28-25 ka and the final stabilization of the form occurred much later possibly after melting of buried dead ice. The younger glacial oscillation (LGM II) occurred no later than 20.5 ka and is represented by well-preserved termino-lateral moraine systems in the Pańszczyca Valley. The first Lateglacial stage (LG1) in the study area is documented in the Rybi Potok Valley at the RP1 moraine (1300 m a.s.l.), which was stable at around 16.6 ± 0.3 ka. The younger LG2 stage has no defined absolute age, however, it is constrained between 16.5 and 15.5 ka by the timing of the LG3 stage. This cold event is represented by well-formed moraines in the Roztoka/Pięć Stawów Polskich, Rybi Potok and Pańszczyca valleys of which exposure age indicates their deposition between 15.0 ± 0.5 and 15.6 ± 0.1 ka. The LG1, LG2 and LG3 stages likely occurred during the Oldest Dryas cold stage (Greenland Stadial 2.1a) related to the North Atlantic cooling Heinrich Event 1. The youngest glacial oscillation is evidenced by moraines in the Pusta and Pańszczyca valleys. These moraines are composed of very large granitic blocks of which exposure ages often exhibit isotope inheritance. This is reflected by the youngest P3 moraine in the Pańszczyca Valley with a mean age of deposition close to the LGM. The R4 moraine system in

Conceptual basis for evaluating risk from low-level radiation exposure

International Nuclear Information System (INIS)

Bond, V.P.

1981-01-01

Serious or lethal injuries that may result from the exposure of animals or human beings to ionizing radiations can be divided into two distinctly different categories, on the basis of whether the injury results only from failure of an entire vital organ, or stems from impairment of the function of a single cell. These two categories of injury are termed here organ effects, normally induced by non-stochastic processes, and single cell effects, normally induced by stochastic processes. This presentation is limited to low-level radiation exposure (LLR) since: (1) only with single hit kinetics does the average number of cell doses per cell in the exposed population essentially equal the number of cells dosed; (2) in excluding multihit all-or-none effects, the functions developed are essentially independent of the time rate at which the (instantaneously deposited) cell doses are laid down, and of considerations of repair of sub-effect injury; and (3) it makes little or no difference with LLR if the incidence of single cell effects is expressed in terms of exposed or surviving cells

Evaluation of Noise Exposure Secondary to Wind Noise in Cyclists.

Science.gov (United States)

Seidman, Michael D; Wertz, Anna G; Smith, Matthew M; Jacob, Steve; Ahsan, Syed F

2017-11-01

Objective Determine if the noise levels of wind exposure experienced by cyclists reach levels that could contribute to noise-induced hearing loss. Study Design Industrial lab research. Setting Industrial wind tunnel. Subjects and Methods A commercial-grade electric wind tunnel was used to simulate different speeds encountered by a cyclist. A single cyclist was used during the simulation for audiometric measurements. Microphones attached near the ears of the cyclist were used to measure the sound (dB sound pressure level) experienced by the cyclist. Loudness levels were measured with the head positioned at 15-degree increments from 0 degrees to 180 degrees relative to the oncoming wind at different speeds (10-60 mph). Results Wind noise ranged from 84.9 dB at 10 mph and increased proportionally with speed to a maximum of 120.3 dB at 60 mph. The maximum of 120.3 dB was measured at the downwind ear when the ear was 90 degrees away from the wind. Conclusions Wind noise experienced by a cyclist is proportional to the speed and the directionality of the wind current. Turbulent air flow patterns are observed that contribute to increased sound exposure in the downwind ear. Consideration of ear deflection equipment without compromising sound awareness for cyclists during prolonged rides is advised to avoid potential noise trauma. Future research is warranted and can include long-term studies including dosimetry measures of the sound and yearly pre- and postexposure audiograms of cyclists to detect if any hearing loss occurs with long-term cycling.

Levels and Determinants of DDT and DDE Exposure in the VHEMBE Cohort.

Science.gov (United States)

Gaspar, Fraser W; Chevrier, Jonathan; Quirós-Alcalá, Lesliam; Lipsitt, Jonah M; Barr, Dana Boyd; Holland, Nina; Bornman, Riana; Eskenazi, Brenda

2017-07-07

Although indoor residual spraying (IRS) is an effective tool for malaria control, its use contributes to high insecticide exposure in sprayed communities and raises concerns about possible unintended health effects. The Venda Health Examination of Mothers, Babies and their Environment (VHEMBE) is a birth cohort study initiated in 2012 to characterize prenatal exposure to IRS insecticides and exposures' impacts on child health and development in rural South Africa. In this report, we describe the VHEMBE cohort and dichlorodiphenyltrichloroethane (DDT) and dichlorodiphenyldichloroethylene (DDE) serum concentrations measured in VHEMBE mothers when they presented for delivery. In addition, we applied a causal inference framework to estimate the potential reduction in population-level p , p' -DDT and p , p' -DDE serum concentrations under five hypothetical interventions. A total of 751 mothers were enrolled. Serum concentrations of p , p' isomers of DDT and DDE were above the limit of detection (LOD) in ≥98% of the samples, whereas the o , p' isomers were above the LOD in at least 80% of the samples. Median (interquartile range) p , p' -DDT and p , p' -DDE serum concentrations for VHEMBE cohort participants were 55.3 (19.0-259.3) and 242.2 (91.8-878.7) ng/g-lipid, respectively. Mothers reporting to have lived in a home sprayed with DDT for malaria control had ~5-7 times higher p , p' -DDT and p , p' -DDE serum concentrations than those who never lived in a home sprayed with DDT. Of the five potential interventions tested, we found increasing access to water significantly reduced p , p' -DDT exposure and increasing the frequency of household wet mopping significantly reduced p , p' -DDT and p , p' -DDE exposure. Our findings suggest that several intervention approaches may reduce DDT/DDE exposure in pregnant women living in IRS communities. https://doi.org/10.1289/EHP353.

Modeling the transmitted and stored energy in multilayer protective clothing under low-level radiant exposure

International Nuclear Information System (INIS)

Su, Yun; He, Jiazhen; Li, Jun

2016-01-01

Highlights: • A numerical model from heating source to skin tissues through multilayer fabric system is developed. • The numerical model is comprehensively validated with experimental data. • The model is used to investigate the relationship between the transmitted and stored energy and the influencing factors. - Abstract: A finite difference model was introduced to simulate the transmitted and stored energy in firefighters' protective clothing exposed to low-level thermal radiation. The model domain consists of a three-layer fire-resistant fabric system (outer shell, moisture barrier, and thermal liner), the human skin, and the air gap between clothing and the skin. The model accounted for the relationship between the transmitted heat during the exposure and the discharged heat during the cooling-down period. The numerical model predictions were compared with experimental data. Additionally, the parameters that affect the transmitted and stored energy of protective clothing were investigated. The results demonstrate that for the typical multilayer firefighter protective clothing, the transmitted heat during exposure and the discharged heat after exposure totally determine the skin burn under low-level heat exposure, especially for third-degree skin burns. The findings obtained in this study can be used to engineer fabric systems that provide better protection for the stored thermal burn.

LEA: An Algorithm to Estimate the Level of Location Exposure in Infrastructure-Based Wireless Networks

Directory of Open Access Journals (Sweden)

Francisco Garcia

2017-01-01

Full Text Available Location privacy in wireless networks is nowadays a major concern. This is due to the fact that the mere fact of transmitting may allow a network to pinpoint a mobile node. We consider that a first step to protect a mobile node in this situation is to provide it with the means to quantify how accurately a network establishes its position. To achieve this end, we introduce the location-exposure algorithm (LEA, which runs on the mobile terminal only and whose operation consists of two steps. In the first step, LEA discovers the positions of nearby network nodes and uses this information to emulate how they estimate the position of the mobile node. In the second step, it quantifies the level of exposure by computing the distance between the position estimated in the first step and its true position. We refer to these steps as a location-exposure problem. We tested our proposal with simulations and testbed experiments. These results show the ability of LEA to reproduce the location of the mobile node, as seen by the network, and to quantify the level of exposure. This knowledge can help the mobile user decide which actions should be performed before transmitting.

Assessment of exposure pathways connected with construction and operation of concrete bridge reinforced with very low level radioactive steel

International Nuclear Information System (INIS)

Panik, M.; Necas, V.

2012-01-01

Large amount of low level radioactive material arises during decommissioning of nuclear power plants. Material mostly comprises metal scrap and concrete ruble. Paper deals with recycling and reuse of metal scrap and its utilization as part of reinforcement of concrete bridges under the conditional release concept. Radiation exposure originating in very low level reinforcement steel consists of several exposure pathways. Short-term radiation impact is represented mostly by external exposure pathway and it is relevant to the construction workers and users of the bridge. Long-term radiation impacts on inhabitants living near finished bridge and it is divided into inhalation and ingestion of radionuclides-internal exposure pathways. Radiation impact caused by utilization of very low level radioactive waste was calculated using simulation software VISIPLAN 3D ALARA and GOLDSIM. Results of calculations provide fair summary of possibilities of utilization of conditionally released steel as reinforcement of concrete bridges. (Authors)

Association of dental enamel lead levels with risk factors for environmental exposure

Directory of Open Access Journals (Sweden)

Kelly Polido Kaneshiro Olympio

2010-10-01

Full Text Available OBJECTIVE: To analyze household risk factors associated with high lead levels in surface dental enamel. METHODS: A cross-sectional study was conducted with 160 Brazilian adolescents aged 14-18 years living in poor neighborhoods in the city of Bauru, southeastern Brazil, from August to December 2008. Body lead concentrations were assessed in surface dental enamel acid-etch microbiopsies. Dental enamel lead levels were measured by graphite furnace atomic absorption spectrometry and phosphorus levels were measured by inductively coupled plasma optical emission spectrometry. The parents answered a questionnaire about their children's potential early (05 years old exposure to well-known lead sources. Logistic regression was used to identify associations between dental enamel lead levels and each environmental risk factor studied. Social and familial covariables were included in the models. RESULTS: The results suggest that the adolescents studied were exposed to lead sources during their first years of life. Risk factors associated with high dental enamel lead levels were living in or close to a contaminated area (OR = 4.49; 95% CI: 1.69;11.97; and member of the household worked in the manufacturing of paints, paint pigments, ceramics or batteries (OR = 3.43; 95% CI: 1.31;9.00. Home-based use of lead-glazed ceramics, low-quality pirated toys, anticorrosive paint on gates and/or sale of used car batteries (OR = 1.31; 95% CI: 0.56;3.03 and smoking (OR = 1.66; 95% CI: 0.52;5.28 were not found to be associated with high dental enamel lead levels. CONCLUSIONS: Surface dental enamel can be used as a marker of past environmental exposure to lead and lead concentrations detected are associated to well-known sources of lead contamination.

Radiofrequency exposure in the Neonatal Medium Care Unit

International Nuclear Information System (INIS)

Calvente, I.; Vázquez-Pérez, A.; Fernández, M.F.; Núñez, M.I.; Múñoz-Hoyos, A.

2017-01-01

The aims of this study were to characterize electromagnetic fields of radiofrequency (RF-EMF) levels generated in a Neonatal Medium Care Unit and to analyze RF-EMF levels inside unit’s incubators. Spot and long-term measurements were made with a dosimeter. The spot measurement mean was 1.51±0.48 V/m. Higher values were found in the proximity to the window and to the incubator evaluated. Mean field strength for the entire period of 17 h was 0.81 (±0.07) V/m and the maximum value was 1.58 V/m for long-term RF-EMF measurements in the incubator. Values found during the night period were higher than those found during the day period. It is important to consider RF-EMF exposure levels in neonatal care units, due to some evidence of adverse health effects found in children and adults. Characterization of RF-EMF exposure may be important to further investigate the mechanisms and underlying effects of electromagnetic fields (EMF) on infant health. A prudent avoidance strategy should be adopted because newborns are at a vulnerable stage of development and the actual impact of EMF on premature infants is unknown. - Highlights: • The increasing use of RF-EMF suggests an urgent need for more research in this field. • Health consequences of RF-EMF exposure on infants are not well known. • Description of RF-EMF exposure is vital in further study mechanisms on infant health. • Considering newborns vulnerability, it is wise to adopt a prudent avoidance strategy.

Radiofrequency exposure in the Neonatal Medium Care Unit

Energy Technology Data Exchange (ETDEWEB)

Calvente, I. [Unit Research Support of the San Cecilio University Hospital, Biosanitary Institute of Granada (ibs.GRANADA), University Hospitals of Granada/University of Granada, Granada (Spain); Department of Radiology and Physical Medicine, School of Medicine, University of Granada, Av. de la Investigación, 11, torre A, planta 11, 18016 Granada (Spain); Vázquez-Pérez, A. [Department of Pediatrics, University of Granada (Spain); Fernández, M.F. [Unit Research Support of the San Cecilio University Hospital, Biosanitary Institute of Granada (ibs.GRANADA), University Hospitals of Granada/University of Granada, Granada (Spain); Department of Radiology and Physical Medicine, School of Medicine, University of Granada, Av. de la Investigación, 11, torre A, planta 11, 18016 Granada (Spain); CIBER en Epidemiología y Salud Pública (CIBERESP) (Spain); Núñez, M.I., E-mail: isabeln@ugr.es [Unit Research Support of the San Cecilio University Hospital, Biosanitary Institute of Granada (ibs.GRANADA), University Hospitals of Granada/University of Granada, Granada (Spain); Department of Radiology and Physical Medicine, School of Medicine, University of Granada, Av. de la Investigación, 11, torre A, planta 11, 18016 Granada (Spain); Biopathology and Regenerative Medicine Institute (IBIMER), University of Granada (Spain); CIBER en Epidemiología y Salud Pública (CIBERESP) (Spain); Múñoz-Hoyos, A. [Department of Pediatrics, University of Granada (Spain)

2017-01-15

The aims of this study were to characterize electromagnetic fields of radiofrequency (RF-EMF) levels generated in a Neonatal Medium Care Unit and to analyze RF-EMF levels inside unit’s incubators. Spot and long-term measurements were made with a dosimeter. The spot measurement mean was 1.51±0.48 V/m. Higher values were found in the proximity to the window and to the incubator evaluated. Mean field strength for the entire period of 17 h was 0.81 (±0.07) V/m and the maximum value was 1.58 V/m for long-term RF-EMF measurements in the incubator. Values found during the night period were higher than those found during the day period. It is important to consider RF-EMF exposure levels in neonatal care units, due to some evidence of adverse health effects found in children and adults. Characterization of RF-EMF exposure may be important to further investigate the mechanisms and underlying effects of electromagnetic fields (EMF) on infant health. A prudent avoidance strategy should be adopted because newborns are at a vulnerable stage of development and the actual impact of EMF on premature infants is unknown. - Highlights: • The increasing use of RF-EMF suggests an urgent need for more research in this field. • Health consequences of RF-EMF exposure on infants are not well known. • Description of RF-EMF exposure is vital in further study mechanisms on infant health. • Considering newborns vulnerability, it is wise to adopt a prudent avoidance strategy.

Coastal vertebrate exposure to predicted habitat changes due to sea level rise

Science.gov (United States)

Hunter, Elizabeth A.; Nibbelink, Nathan P.; Alexander, Clark R.; Barrett, Kyle; Mengak, Lara F.; Guy, Rachel; Moore, Clinton; Cooper, Robert J.

2015-01-01

Sea level rise (SLR) may degrade habitat for coastal vertebrates in the Southeastern United States, but it is unclear which groups or species will be most exposed to habitat changes. We assessed 28 coastal Georgia vertebrate species for their exposure to potential habitat changes due to SLR using output from the Sea Level Affecting Marshes Model and information on the species’ fundamental niches. We assessed forecasted habitat change up to the year 2100 using three structural habitat metrics: total area, patch size, and habitat permanence. Almost all of the species (n = 24) experienced negative habitat changes due to SLR as measured by at least one of the metrics. Salt marsh and ocean beach habitats experienced the most change (out of 16 categorical land cover types) across the three metrics and species that used salt marsh extensively (rails and marsh sparrows) were ranked highest for exposure to habitat changes. Species that nested on ocean beaches (Diamondback Terrapins, shorebirds, and terns) were also ranked highly, but their use of other foraging habitats reduced their overall exposure. Future studies on potential effects of SLR on vertebrates in southeastern coastal ecosystems should focus on the relative importance of different habitat types to these species’ foraging and nesting requirements. Our straightforward prioritization approach is applicable to other coastal systems and can provide insight to managers on which species to focus resources, what components of their habitats need to be protected, and which locations in the study area will provide habitat refuges in the face of SLR.

CHEMICAL WEAPONS: DoD Does Not Have a Strategy to Address Low-Level Exposures

National Research Council Canada - National Science Library

1998-01-01

The possible exposure of U.S. troops to low levels of chemical warfare agents in Iraq in the weeks after the Gulf War ceasefire, along with chemical warfare prophylaxis, vaccines, oil well fire emissions, and other battlefield...

Acrylamide exposure among Turkish toddlers from selected cereal-based baby food samples.

Science.gov (United States)

Cengiz, Mehmet Fatih; Gündüz, Cennet Pelin Boyacı

2013-10-01

In this study, acrylamide exposure from selected cereal-based baby food samples was investigated among toddlers aged 1-3 years in Turkey. The study contained three steps. The first step was collecting food consumption data and toddlers' physical properties, such as gender, age and body weight, using a questionnaire given to parents by a trained interviewer between January and March 2012. The second step was determining the acrylamide levels in food samples that were reported on by the parents in the questionnaire, using a gas chromatography-mass spectrometry (GC-MS) method. The last step was combining the determined acrylamide levels in selected food samples with individual food consumption and body weight data using a deterministic approach to estimate the acrylamide exposure levels. The mean acrylamide levels of baby biscuits, breads, baby bread-rusks, crackers, biscuits, breakfast cereals and powdered cereal-based baby foods were 153, 225, 121, 604, 495, 290 and 36 μg/kg, respectively. The minimum, mean and maximum acrylamide exposures were estimated to be 0.06, 1.43 and 6.41 μg/kg BW per day, respectively. The foods that contributed to acrylamide exposure were aligned from high to low as bread, crackers, biscuits, baby biscuits, powdered cereal-based baby foods, baby bread-rusks and breakfast cereals. Copyright © 2013 Elsevier Ltd. All rights reserved.

Maximum likelihood estimation for cytogenetic dose-response curves

International Nuclear Information System (INIS)

Frome, E.L; DuFrain, R.J.

1983-10-01

In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa[γd + g(t, tau)d 2 ], where t is the time and d is dose. The coefficient of the d 2 term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure

Maximum likelihood estimation for cytogenetic dose-response curves

Energy Technology Data Exchange (ETDEWEB)

Frome, E.L; DuFrain, R.J.

1983-10-01

In vitro dose-response curves are used to describe the relation between the yield of dicentric chromosome aberrations and radiation dose for human lymphocytes. The dicentric yields follow the Poisson distribution, and the expected yield depends on both the magnitude and the temporal distribution of the dose for low LET radiation. A general dose-response model that describes this relation has been obtained by Kellerer and Rossi using the theory of dual radiation action. The yield of elementary lesions is kappa(..gamma..d + g(t, tau)d/sup 2/), where t is the time and d is dose. The coefficient of the d/sup 2/ term is determined by the recovery function and the temporal mode of irradiation. Two special cases of practical interest are split-dose and continuous exposure experiments, and the resulting models are intrinsically nonlinear in the parameters. A general purpose maximum likelihood estimation procedure is described and illustrated with numerical examples from both experimental designs. Poisson regression analysis is used for estimation, hypothesis testing, and regression diagnostics. Results are discussed in the context of exposure assessment procedures for both acute and chronic human radiation exposure.

Public safety assessment of electromagnetic radiation exposure from mobile base stations.

Science.gov (United States)

Alhekail, Z O; Hadi, M A; Alkanhal, M A

2012-09-01

Exposure of the general public to electromagnetic radiation originating from randomly selected GSM/WCDMA base stations in Riyadh, Kingdom of Saudi Arabia has been assessed in the context of the International Commission on Non-Ionising Radiation Protection (ICNIRP) guidelines. The purpose of the measurement was to record the maximum power density of signals to estimate possible worst case exposure at each measurement location. These power density measurements were carried out at 60 mobile base stations located in different regions of the city. For each of these sites, three sectors were operational, yielding a total of 180 sectors. Two positions were identified per site with the greatest power density values. Exposures from these base stations were generally found to be in the range of 0.313 to 0.00000149% of the ICNIRP general public reference level, and the greatest exposure near any of the base stations was 21.96 mW m(-2) for a wideband measurement in the 75-3000 MHz frequency range. Analysis of the measured data reveals several trends for different mobile bands with respect to maximum exposure in those locations. Additionally, a simplified calculation method for the electromagnetic fields was used to compare calculated and the measured data. It was determined, on the basis of both results of the measurements and calculations carried out for these selected base stations, that members of the public would not be exposed to in excess of a small fraction of the ICNIRP guidelines at any of those sites. These are first such measurements to be made in the Middle East and provide assurance that exposures in this region of the world do not seem to be any greater than elsewhere.

The Relationship Between Population-Level Exposure to Alcohol Advertising on Television and Brand-Specific Consumption Among Underage Youth in the US

Science.gov (United States)

Ross, Craig S.; Maple, Emily; Siegel, Michael; DeJong, William; Naimi, Timothy S.; Padon, Alisa A.; Borzekowski, Dina L.G.; Jernigan, David H.

2015-01-01

Aims: We investigated the population-level relationship between exposure to brand-specific advertising and brand-specific alcohol use among US youth. Methods: We conducted an internet survey of a national sample of 1031 youth, ages 13–20, who had consumed alcohol in the past 30 days. We ascertained all of the alcohol brands respondents consumed in the past 30 days, as well as which of 20 popular television shows they had viewed during that time period. Using a negative binomial regression model, we examined the relationship between aggregated brand-specific exposure to alcohol advertising on the 20 television shows [ad stock, measured in gross rating points (GRPs)] and youth brand-consumption prevalence, while controlling for the average price and overall market share of each brand. Results: Brands with advertising exposure on the 20 television shows had a consumption prevalence about four times higher than brands not advertising on those shows. Brand-level advertising elasticity of demand varied by exposure level, with higher elasticity in the lower exposure range. The estimated advertising elasticity of 0.63 in the lower exposure range indicates that for each 1% increase in advertising exposure, a brand's youth consumption prevalence increases by 0.63%. Conclusions: At the population level, underage youths' exposure to brand-specific advertising was a significant predictor of the consumption prevalence of that brand, independent of each brand's price and overall market share. The non-linearity of the observed relationship suggests that youth advertising exposure may need to be lowered substantially in order to decrease consumption of the most heavily advertised brands. PMID:25754127

Increased levels of oxidative DNA damage in pesticide sprayers in Thessaly Region (Greece). Implications of pesticide exposure.

Science.gov (United States)

Koureas, Michalis; Tsezou, Aspasia; Tsakalof, Andreas; Orfanidou, Timoklia; Hadjichristodoulou, Christos

2014-10-15

The widespread use of pesticides substances nowadays largely guarantees the protection of crops and people from undesired pests. However, exposure to pesticides was related to a variety of human health effects. The present study was conducted in the region of Thessaly which is characterized by intensive agricultural activities and wide use of pesticides. The study aimed at estimating the oxidative damage to DNA in different subpopulations in Thessaly region (Greece) and investigating its correlation with exposure to pesticides and other potential risk factors. In total, the study involved 80 pesticide sprayers, 85 rural residents and 121 individuals, inhabitants of the city of Larissa. Demographic characteristics, habits, medical history and exposure history of the participants to pesticides were recorded by personal interviews. Blood and urine samples were collected from all participants. For the measurement of exposure to organophosphorus insecticides, dialkylphosphate (DAP) metabolites were quantified in urine, by gas chromatography-mass spectrometry. Genomic DNA was extracted from peripheral blood samples and the oxidation by-product 8-hydroxydeoxyguanosine (8-OHdG) was determined by Enzyme Immuno-Assay. Urinary metabolite concentrations were not associated with 8-OHdG levels but it was found that pesticide sprayers had significantly higher levels of 8-OHdG (p=0.007) in comparison to the control group. Last season's exposure to insecticides and fungicides, expressed as total area treated multiplied by the number of applications, showed a statistically significant association with the risk of having high 8-OHdG levels [RR: 2.19 (95%CI:1.09-4.38) and RR: 2.32 (95% CI:1.16-4.64) respectively]. Additionally, from the subgroups of pesticides examined, seasonal exposure to neonicotinoid insecticides [RR: 2.22 (95% CI:1.07-4.63)] and glufosinate ammonium [RR: 3.26 (95% CI:1.38-7.69)] was found to have the greater impact on 8-OHdG levels. This study produced findings

Exposure levels, determinants and IgE mediated sensitization to bovine allergens among Danish farmers and non-farmers

NARCIS (Netherlands)

Schlünssen, V; Basinas, I; Zahradnik, E; Elholm, G; Wouters, I M; Kromhout, H; Heederik, D; Bolund, A C S; Omland, Ø; Raulf, M; Sigsgaard, T

BACKGROUND: Bovine allergens can induce allergic airway diseases. High levels of allergens in dust from stables and homes of dairy farmers have been reported, but sparse knowledge about determinants for bovine allergen levels and associations between exposure level and sensitization is available.

Effects of dietary lead exposure on vitamin levels in great tit nestlings – An experimental manipulation

International Nuclear Information System (INIS)

Ruiz, Sandra; Espín, Silvia; Rainio, Miia; Ruuskanen, Suvi; Salminen, Juha-Pekka; Lilley, Thomas M.; Eeva, Tapio

2016-01-01

Exposure to metal pollution negatively affects animal physiology, including nutrient metabolism, but in the wild an effect can seldom be attributed to a single metal. Moreover, little is known about how the metabolism of vitamins, essential micronutrients for developing juveniles, is affected by toxic metals. Therefore we experimentally investigated the effects of lead (Pb), a widespread toxic metal, on four fat-soluble vitamins A (total and retinol), D 3 , E (total and α-tocopherol) and K and carotenoids (lutein, zeaxanthin and unidentified) in great tit (Parus major) nestlings. In addition to a control group where no Pb was provided, two Pb-dosed groups were compared to a metal exposed group in the vicinity of a Ni–Cu smelter. We examined whether Pb treatment affects vitamin homeostasis and how the response of Pb-treated birds relates to that of a population under industrial exposure of Pb and other metals. For this purpose, vitamin and carotenoid levels were quantified with UPLC-MS from plasma of 7 days-old nestlings. All metal exposed groups showed increased vitamin A and retinol levels. However, vitamin levels were not directly associated with fecal Pb levels, with the exception of retinol, which was positively correlated with fecal Pb. Alpha-tocopherol, lutein and zeaxanthin levels were positively associated with body mass and wing growth rate. To conclude, Pb exposure increased plasma vitamin A and retinol levels while the levels of other vitamins and carotenoids rather reflected secondary pollution effects via differences in habitat and diet quality at the smelter site. Our findings suggest Pb exposed nestlings may allocate the vitamins needed for growth and development to fight the physiological stress thus compromising their fitness. - Highlights: • Pb effects on vitamins A, D 3 , E and K in wild great tit nestlings were investigated. • Four treatment groups were established: Control, Low-Pb, High-Pb and Smelter. • Pb concentrations measured in

Pyrethroid insecticide exposure and reproductive hormone levels in healthy Japanese male subjects

DEFF Research Database (Denmark)

Yoshinaga, J; Imai, K; Shiraishi, H

2014-01-01

)] were explored in 322 male university students in suburban Tokyo. The subjects constituted part of a large cross-sectional survey on the reference value of semen quality of Japanese men. Urinary 3-PBA was detectable in 91% of the subjects demonstrating ubiquitous exposure among the general population....... However, there were no associations between urinary 3-PBA and serum hormone levels. This result was inconsistent with those reported in China and the USA for subjects who had similar levels of urinary 3-PBA to the present subjects. One of the possible reasons of the inconsistency might be different...

Occurrence of 210Po and Biological Effects of Low-Level Exposure: The Need for Research

Science.gov (United States)

Wiemels, Joseph L.

2012-01-01

Background: Polonium-210 (210Po) concentrations that exceed 1 Bq/L in drinking-water supplies have been reported from four widely separated U.S. states where exposure to it went unnoticed for decades. The radionuclide grandparents of 210Po are common in sediments, and segments of the public may be chronically exposed to low levels of 210Po in drinking water or in food products from animals raised in contaminated areas. Objectives: We summarized information on the environmental behavior, biokinetics, and toxicology of 210Po and identified the need for future research. Methods: Potential linkages between environmental exposure to 210Po and human health effects were identified in a literature review. Discussion: 210Po accumulates in the ovaries where it kills primary oocytes at low doses. Because of its radiosensitivity and tendency to concentrate 210Po, the ovary may be the critical organ in determining the lowest injurious dose for 210Po. 210Po also accumulates in the yolk sac of the embryo and in the fetal and placental tissues. Low-level exposure to 210Po may have subtle, long-term biological effects because of its tropism towards reproductive and embryonic and fetal tissues where exposure to a single alpha particle may kill or damage critical cells. 210Po is present in cigarettes and maternal smoking has several effects that appear consistent with the toxicology of 210Po. Conclusions: Much of the important biological and toxicological research on 210Po is more than four decades old. New research is needed to evaluate environmental exposure to 210Po and the biological effects of low-dose exposure to it so that public health officials can develop appropriate mitigation measures where necessary. PMID:22538346

Prioritizing Type of Industry through Health Risk Assessment of Occupational Exposure to Dimethylformamide in the Workplace.

Science.gov (United States)

Lee, Junghyun; Hahm, Miran; Huh, Da-An; Byeon, Sang-Hoon

2018-03-13

The purpose of this study was to classify hazards at an industrial level and evaluate the exposure risks of workers exposed to dimethylformamide (DMF) used as a solvent in the workplace and to determine industries that need priority measures in managing DMF exposure. We calculated hazard quotients at an industrial level. The exposure data of DMF in the workplace were obtained from the work environment monitoring program provided by the Korea Occupational Safety and Health Agency. The evaluation was conducted on textile manufacturing, leather manufacturing, chemical manufacturing, pharmaceutical manufacturing, and rubber manufacturing industries, which have many unit work sites handling DMF. The highest central tendency exposure and reasonable maximum exposure were 2.13 and 18.66 mg/m³ for the rubber product manufacturing industry, respectively. A total of 63.8% of workplaces in the textile manufacturing sector had a hazard quotient higher than 1. The highest risk for exposure to DMF is in the rubber and plastic manufacturing industry, and the lowest risk was in the medical materials and pharmaceutical manufacturing sector. Based on this study, effective management of DMF exposure could be achieved by establishing priority management measures for the textile and rubber and plastic product industries.

Multiple Maximum Exposure Rates in Computerized Adaptive Testing

Science.gov (United States)

Ramon Barrada, Juan; Veldkamp, Bernard P.; Olea, Julio

2009-01-01

Computerized adaptive testing is subject to security problems, as the item bank content remains operative over long periods and administration time is flexible for examinees. Spreading the content of a part of the item bank could lead to an overestimation of the examinees' trait level. The most common way of reducing this risk is to impose a…

Exposure to ultrafine particles, intracellular production of reactive oxygen species in leukocytes and altered levels of endothelial progenitor cells

DEFF Research Database (Denmark)

Jantzen, Kim; Møller, Peter Horn; Karottki, Dorina Gabriela

2016-01-01

. Additionally, the early endothelial progenitor cell levels were positively associated with a personalised measure of ultrafine particle exposure and negatively associated with both basal and capacity for reactive oxygen species production in lymphocytes and granulocytes, respectively. Our results indicate......Exposure to particles in the fine and ultrafine size range has been linked to induction of low-grade systemic inflammation, oxidative stress and development of cardiovascular diseases. Declining levels of endothelial progenitor cells within systemic circulation have likewise been linked...... to progression of cardiovascular diseases. The objective was to determine if exposure to fine and ultrafine particles from indoor and outdoor sources, assessed by personal and residential indoor monitoring, is associated with altered levels of endothelial progenitor cells, and whether such effects are related...

Suitability of the charm HVS and a microbiological multiplate system for detection of residues in raw milk at EU maximum residue levels

NARCIS (Netherlands)

Nouws, J.F.M.; Egmond, van H.; Loeffen, G.; Schouten, J.; Keukens, H.; Smulders, I.; Stegeman, H.

1999-01-01

In this paper we assessed the suitability of the Charm HVS and a newly developed microbiological multiplate system as post-screening tests to confirm the presence of residues in raw milk at or near the maximum permissible residue level (MRL). The multiplate system is composed of Bacillus

Radiation exposure distribution in patients undergoing CT brain scans

International Nuclear Information System (INIS)

Yang Zhanshan; Feng Dinghua; Chang Zichi; Li Shijun

1989-12-01

The distribution of surface exposures in patients undergoing single and multiple computerized tomographic brain scans with Hitachi CT-W500 was measured by LiF(Mg, Ti) thermoluminescent dosimetry. It was found that there was no significant difference in the sufrace exposures from different scanning slices. However, the exposure doses at different scanning angles around the head were different significantly. The reference point of the maximum surface exposure was at the temporal part of the head. the maximum surface exposure was at 1.65 x 10 -3 C·kg -1 while the average exposure was 1.55 x 10 -3 C·kg -1 . The ratio of the average dose resulting from nine scans to that from a single scan was 1.3, and the surface exposure contribution of scattered radiation was computed. At the same time the radiation doses to eyes, thyroid, chest and gonads of patiens at corresponding position were also measured and were compared with those from CT cranial scans in children and skull radiographic procedures respectively

Levels and source apportionment of children's lead exposure: could urinary lead be used to identify the levels and sources of children's lead pollution?

Science.gov (United States)

Cao, Suzhen; Duan, Xiaoli; Zhao, Xiuge; Wang, Beibei; Ma, Jin; Fan, Delong; Sun, Chengye; He, Bin; Wei, Fusheng; Jiang, Guibin

2015-04-01

As a highly toxic heavy metal, the pollution and exposure risks of lead are of widespread concern for human health. However, the collection of blood samples for use as an indicator of lead pollution is not always feasible in most cohort or longitudinal studies, especially those involving children health. To evaluate the potential use of urinary lead as an indicator of exposure levels and source apportionment, accompanying with environmental media samples, lead concentrations and isotopic measurements (expressed as (207)Pb/(206)Pb, (208)Pb/(206)Pb and (204)Pb/(206)Pb) were investigated and compared between blood and urine from children living in the vicinities of a typical coking plant and lead-acid battery factory. The results showed urinary lead might not be a preferable proxy for estimating blood lead levels. Fortunately, urinary lead isotopic measurements could be used as an alternative for identifying the sources of children's lead exposure, which coincided well with the blood lead isotope ratio analysis. Copyright © 2015 Elsevier Ltd. All rights reserved.

Family environmental and dietary implications for low-level prenatal lead exposure in Wujiang City, China.

Science.gov (United States)

Yan, Jin; Gao, Zhenyan; Wang, Ju; Ma, Wenjuan; Ying, Xiaolan; Zhou, Cancan; Yan, Chonghuai

2018-05-01

To explore the potential environmental and dietary factors during pregnancy affecting low-level prenatal lead exposure, we conducted a longitudinal study in Wujiang City, China. A total of 1976 mother-infant pairs were included from 2009 to 2010. An interviewed questionnaire was conducted and cord blood samples were collected. The geometric means of cord blood lead level was 30.3 μg/L (95% CI, 29.8-30.8) with 99.24% below 100 μg/L. Maternal age, passive smoking, and living in the countryside were significantly associated with cord blood lead concentrations. Multiple logistic models showed that some family environmental factors including using firewood and electricity as kitchen fuel were positively correlated with increased cord blood lead levels. Among dietary sources recorded in this study, meat consumption (> 3 times/week), fish consumption (1-3 times/week), vegetables consumption (> 1 times/day), and fruit intake (> 1 times/day) had inverse relationship with cord blood lead levels. In general, our findings may have important implications for family environmental and dietary direction during pregnancy to decrease prenatal lead exposure.

Estimation of exposure to furan in the Spanish population.

Science.gov (United States)

Mesías, Marta; Guerra-Hernández, Eduardo; García-Villanova, Belén

2012-02-01

The presence of furan in foods has received recent attention because of its association with harmful effects to human health. This compound, which is originated as a consequence of thermal treatment, is mainly found in canned, jarred, toasted and fried foods. The aim of this study was to estimate the exposure to furan in the Spanish population and to study the evolution of furan content in the main categories of foods in recent years, taking into account changes in dietary patterns. With respect to exposure to furan in the Spanish population from 2001 to 2009, no large differences were found. The maximum furan exposure recorded in this study (1.95 μg/kg bw/day) is lower than the 'no observable adverse effect level' of 0.08 mg/kg bw/day determined in the studies of experimental animals, and is close to the reported acceptable daily intake of 2 μg/kg bw/day.

Statistical Methods and Software for the Analysis of Occupational Exposure Data with Non-detectable Values

Energy Technology Data Exchange (ETDEWEB)

Frome, EL

2005-09-20

Environmental exposure measurements are, in general, positive and may be subject to left censoring; i.e,. the measured value is less than a ''detection limit''. In occupational monitoring, strategies for assessing workplace exposures typically focus on the mean exposure level or the probability that any measurement exceeds a limit. Parametric methods used to determine acceptable levels of exposure, are often based on a two parameter lognormal distribution. The mean exposure level, an upper percentile, and the exceedance fraction are used to characterize exposure levels, and confidence limits are used to describe the uncertainty in these estimates. Statistical methods for random samples (without non-detects) from the lognormal distribution are well known for each of these situations. In this report, methods for estimating these quantities based on the maximum likelihood method for randomly left censored lognormal data are described and graphical methods are used to evaluate the lognormal assumption. If the lognormal model is in doubt and an alternative distribution for the exposure profile of a similar exposure group is not available, then nonparametric methods for left censored data are used. The mean exposure level, along with the upper confidence limit, is obtained using the product limit estimate, and the upper confidence limit on an upper percentile (i.e., the upper tolerance limit) is obtained using a nonparametric approach. All of these methods are well known but computational complexity has limited their use in routine data analysis with left censored data. The recent development of the R environment for statistical data analysis and graphics has greatly enhanced the availability of high-quality nonproprietary (open source) software that serves as the basis for implementing the methods in this paper.

Workplaces with elevated levels of exposure to natural radiation: The situation in Sweden

International Nuclear Information System (INIS)

Mjoenes, L.; Aakerblom, G.

2002-01-01

Because of the geological conditions with an abundance of granites and pegmatites rich in uranium and thorium together with large areas of uranium-rich alum shale, exposure from natural radiation is not unusual in certain types of industries and other work activities in Sweden. Although no representative survey of radon at regular workplaces has been performed in Sweden, smaller surveys and the high radon concentrations in dwellings indicate that workplaces with elevated radon levels are frequent in Sweden. Very high levels of indoor radon have been found in waterworks. Radon in mines has been regulated in Sweden since 1972 and radon in other workplaces since 1990. The situation in schools and day-care centres was thoroughly investigated in 2000. The estimated number of school and child care buildings with radon concentrations exceeding the action level 400 Bq/m 3 , is 800, about 200 of these have been identified and in about 100 buildings remedial measures have been taken. Regulations for natural radioactivity in building materials (for new buildings) have been in force since 1980. Lightweight concrete produced from uranium-rich alum shale was in use between 1929 and 1975. Almost 400,000 dwellings, 10 percent of the building stock, contain this material. The situation at NORM (Naturally Occurring Radioactive Material) industries is currently being investigated. Since the beginning of the 1950s it is known that residues from several industrial activities contain enhanced levels of natural radioactivity. Some examples are burnt alum shale from lime burning, radium-rich slag from metal production and waste gypsum from sulphuric acid production. The impact of the exposure from these residues is now being reinvestigated. So far no systematic search for up to now unknown work activities where substantial exposures from natural radiation could occur, has been initiated. For the protection of aircrew from cosmic radiation the responsible Swedish authorities have

Ozone pollution and ozone biomonitoring in European cities. Part I: Ozone concentrations and cumulative exposure indices at urban and suburban sites

DEFF Research Database (Denmark)

Klumpp, A.; Ansel, W.; Klumpp, G.

2006-01-01

In the frame of a European research project on air quality in urban agglomerations, data on ozone concentrations from 23 automated urban and suburban monitoring stations in 11 cities from seven countries were analysed and evaluated. Daily and summer mean and maximum concentrations were computed...... based on hourly mean values, and cumulative ozone exposure indices (Accumulated exposure Over a Threshold of 40 ppb (AOT40), AOT20) were calculated. The diurnal profiles showed a characteristic pattern in most city centres, with minimum values in the early morning hours, a strong rise during the morning......, by contrast, maximum values were lower and diurnal variation was much smaller. Based on ozone concentrations as well as on cumulative exposure indices, a clear north-south gradient in ozone pollution, with increasing levels from northern and northwestern sites to central and southern European sites...

Metabonomics of Pig Blood Plasma Following Whole Body Exposure to Low Levels of Gb Vapor

National Research Council Canada - National Science Library

Bevilacqua, Vicky L; D'Onofrio, Terreiice G; Jakubowski, K. M; Hulet, Stanley W; Maguire, Kelly J; Edwards, Jennifer L; Laramee, James A; Brickhouse, Mark D

2005-01-01

...), for which complex data must be analyzed. Therefore, we have begun an exploration of the use of chemometrics for the correlation of metabolic change with low-level CWA exposure in animal models...

Impact of a proposed revision of the IESTI equation on the acute risk assessment conducted when setting maximum residue levels (MRLs) in the European Union (EU): A case study.

Science.gov (United States)

Breysse, Nicolas; Vial, Gaelle; Pattingre, Lauriane; Ossendorp, Bernadette C; Mahieu, Karin; Reich, Hermine; Rietveld, Anton; Sieke, Christian; van der Velde-Koerts, Trijntje; Sarda, Xavier

2018-06-03

Proposals to update the methodology for the international estimated short-term intake (IESTI) equations were made during an international workshop held in Geneva in 2015. Changes to several parameters of the current four IESTI equations (cases 1, 2a, 2b, and 3) were proposed. In this study, the overall impact of these proposed changes on estimates of short-term exposure was studied using the large portion data available in the European Food Safety Authority PRIMo model and the residue data submitted in the framework of the European Maximum Residue Levels (MRL) review under Article 12 of Regulation (EC) No 396/2005. Evaluation of consumer exposure using the current and proposed equations resulted in substantial differences in the exposure estimates; however, there were no significant changes regarding the number of accepted MRLs. For the different IESTI cases, the median ratio of the new versus the current equation is 1.1 for case 1, 1.4 for case 2a, 0.75 for case 2b, and 1 for case 3. The impact, expressed as a shift in the IESTI distribution profile, indicated that the 95th percentile IESTI shifted from 50% of the acute reference dose (ARfD) with the current equations to 65% of the ARfD with the proposed equations. This IESTI increase resulted in the loss of 1.2% of the MRLs (37 out of 3110) tested within this study. At the same time, the proposed equations would have allowed 0.4% of the MRLs (14 out of 3110) that were rejected with the current equations to be accepted. The commodity groups that were most impacted by these modifications are solanacea (e.g., potato, eggplant), lettuces, pulses (dry), leafy brassica (e.g., kale, Chinese cabbage), and pome fruits. The active substances that were most affected were fluazifop-p-butyl, deltamethrin, and lambda-cyhalothrin.

Blood lead and carboxyhemoglobin levels in chainsaw operators.

Science.gov (United States)

van Netten, C; Brubaker, R L; Mackenzie, C J; Godolphin, W J

1987-06-01

Fallers in the British Columbia west coast lumber industry often work in climatic and local conditions where little ventilation in their immediate environment is possible. Under these conditions carbon monoxide (CO) and lead fumes from exhaust gases could build up and become a serious occupational hazard. This study monitored the environmental exposure of six fallers to carbon monoxide, nitrogen oxides, and lead under conditions where buildup of these agents would be expected. At the same time blood samples were taken to correlate these environmental concentrations to carboxyhemoglobin (COHb) and blood lead levels. Although there was a highly significant difference between the fallers and the controls regarding the exposure to CO and lead as well as their corresponding COHb and blood lead levels, the environmental and blood concentration of the agents in question did not exceed the maximum allowable concentrations. Temporary short fluctuations in carboxyhemoglobin levels were not monitored in this study and cannot be ruled out as a potential occupational hazard.

Blood lead and carboxyhemoglobin levels in chainsaw operators

Energy Technology Data Exchange (ETDEWEB)

van Netten, C.; Brubaker, R.L.; Mackenzie, C.J.; Godolphin, W.J.

1987-06-01

Fallers in the British Columbia west coast lumber industry often work in climatic and local conditions where little ventilation in their immediate environment is possible. Under these conditions carbon monoxide (CO) and lead fumes from exhaust gases could build up and become a serious occupational hazard. This study monitored the environmental exposure of six fallers to carbon monoxide, nitrogen oxides, and lead under conditions where buildup of these agents would be expected. At the same time blood samples were taken to correlate these environmental concentrations to carboxyhemoglobin (COHb) and blood lead levels. Although there was a highly significant difference between the fallers and the controls regarding the exposure to CO and lead as well as their corresponding COHb and blood lead levels, the environmental and blood concentration of the agents in question did not exceed the maximum allowable concentrations. Temporary short fluctuations in carboxyhemoglobin levels were not monitored in this study and cannot be ruled out as a potential occupational hazard.

The relationship between population-level exposure to alcohol advertising on television and brand-specific consumption among underage youth in the US.

Science.gov (United States)

Ross, Craig S; Maple, Emily; Siegel, Michael; DeJong, William; Naimi, Timothy S; Padon, Alisa A; Borzekowski, Dina L G; Jernigan, David H

2015-05-01

We investigated the population-level relationship between exposure to brand-specific advertising and brand-specific alcohol use among US youth. We conducted an internet survey of a national sample of 1031 youth, ages 13-20, who had consumed alcohol in the past 30 days. We ascertained all of the alcohol brands respondents consumed in the past 30 days, as well as which of 20 popular television shows they had viewed during that time period. Using a negative binomial regression model, we examined the relationship between aggregated brand-specific exposure to alcohol advertising on the 20 television shows [ad stock, measured in gross rating points (GRPs)] and youth brand-consumption prevalence, while controlling for the average price and overall market share of each brand. Brands with advertising exposure on the 20 television shows had a consumption prevalence about four times higher than brands not advertising on those shows. Brand-level advertising elasticity of demand varied by exposure level, with higher elasticity in the lower exposure range. The estimated advertising elasticity of 0.63 in the lower exposure range indicates that for each 1% increase in advertising exposure, a brand's youth consumption prevalence increases by 0.63%. At the population level, underage youths' exposure to brand-specific advertising was a significant predictor of the consumption prevalence of that brand, independent of each brand's price and overall market share. The non-linearity of the observed relationship suggests that youth advertising exposure may need to be lowered substantially in order to decrease consumption of the most heavily advertised brands. © The Author 2015. Medical Council on Alcohol and Oxford University Press. All rights reserved.

Exposure to environmentally-relevant levels of ozone negatively influence pollen and fruit development

International Nuclear Information System (INIS)

Gillespie, Colin; Stabler, Daniel; Tallentire, Eva; Goumenaki, Eleni; Barnes, Jeremy

2015-01-01

A combination of in vitro and in vivo studies on tomato (Lycopersicon esculentum Mill. cv. Triton) revealed that environmentally-relevant levels of ozone (O_3) pollution adversely affected pollen germination, germ tube growth and pollen-stigma interactions – pollen originating from plants raised in charcoal-Purafil"® filtered air (CFA) exhibited reduced germ tube development on the stigma of plants exposed to environmentally-relevant levels of O_3. The O_3-induced decline in in vivo pollen viability was reflected in increased numbers of non-fertilized and fertilized non-viable ovules in immature fruit. Negative effects of O_3 on fertilization occurred regardless of the timing of exposure, with reductions in ovule viability evident in O_3 × CFA and CFA × O_3 crossed plants. This suggests O_3-induced reductions in fertilization were associated with reduced pollen viability and/or ovule development. Fruit born on trusses independently exposed to 100 nmol mol"−"1 O_3 (10 h d"−"1) from flowering exhibited a decline in seed number and this was reflected in a marked decline in the weight and size of individual fruit – a clear demonstration of the direct consequence of the effects of the pollutant on reproductive processes. Ozone exposure also resulted in shifts in the starch and ascorbic acid (Vitamin C) content of fruit that were consistent with accelerated ripening. The findings of this study draw attention to the need for greater consideration of, and possibly the adoption of weightings for the direct impacts of O_3, and potentially other gaseous pollutants, on reproductive biology during ‘risk assessment’ exercises. - Highlights: • Environmentally-relevant levels of ozone exert negative effects on pollen viability that translate into direct impacts on fruit yield. • Negative impacts of O_3 pollution on reproductive processes were evident regardless of the stage of plant development. • Exposure to environmentally-relevant levels of O_3

Estimating Benzene Exposure Level over Time and by Industry Type through a Review of Literature on Korea.

Science.gov (United States)

Park, Donguk; Choi, Sangjun; Ha, Kwonchul; Jung, Hyejung; Yoon, Chungsik; Koh, Dong-Hee; Ryu, Seunghun; Kim, Soogeun; Kang, Dongmug; Yoo, Kyemook

2015-09-01

The major purpose of this study is to construct a retrospective exposure assessment for benzene through a review of literature on Korea. Airborne benzene measurements reported in 34 articles were reviewed. A total of 15,729 individual measurements were compiled. Weighted arithmetic means [AM(w)] and their variance calculated across studies were summarized according to 5-year period intervals (prior to the 1970s through the 2010s) and industry type. Industries were classified according to Korea Standard Industrial Classification (KSIC) using information provided in the literature. We estimated quantitative retrospective exposure to benzene for each cell in the matrix through a combination of time and KSIC. Analysis of the AM(w) indicated reductions in exposure levels over time, regardless of industry, with mean levels prior to the 1980-1984 period of 50.4 ppm (n = 2,289), which dropped to 2.8 ppm (n = 305) in the 1990-1994 period, and to 0.1 ppm (n = 294) in the 1995-1999 period. There has been no improvement since the 2000s, when the AM(w) of 4.3 ppm (n = 6,211) for the 2005-2009 period and 4.5 ppm (n = 3,358) for the 2010-2013 period were estimated. A comparison by industry found no consistent patterns in the measurement results. Our estimated benzene measurements can be used to determine not only the possibility of retrospective exposure to benzene, but also to estimate the level of quantitative or semiquantitative retrospective exposure to benzene.

Exposure to airborne ultrafine particles from cooking in Portuguese homes.

Science.gov (United States)

Bordado, J C; Gomes, J F; Albuquerque, P C

2012-10-01

Cooking was found to be a main source of submicrometer and ultrafine aerosols from gas combustion in stoves. Therefore, this study consisted of the determination of the alveolar deposited surface area due to aerosols resulting from common domestic cooking activities (boiling fish, vegetables, or pasta, and frying hamburgers and eggs). The concentration of ultrafine particles during the cooking events significantly increased from a baseline of 42.7 microm2/cm3 (increased to 72.9 microm2/cm3 due to gas burning) to a maximum of 890.3 microm2/cm3 measured during fish boiling in water and a maximum of 4500 microm2/cm3 during meat frying. This clearly shows that a domestic activity such as cooking can lead to exposures as high as those of occupational exposure activities. The approach of this study considers the determination of alveolar deposited surface area of aerosols generated from cooking activities, namely, typical Portuguese dishes. This type of measurement has not been done so far, in spite of the recognition that cooking activity is a main source of submicrometer and ultrafine aerosols. The results have shown that the levels of generated aerosols surpass the outdoor concentrations in a major European town, which calls for further determinations, contributing to a better assessment of exposure of individuals to domestic activities such as this one.

Monitoring of low level environmental gamma exposure by the centralized radiation monitoring system

International Nuclear Information System (INIS)

Katagiri, Hiroshi; Kobayashi, Hideo; Obata, Kazuichi; Kokubu, Morinobu; Itoh, Naoji

1981-07-01

In the Japan Atomic Energy Research Institute (JAERI), a centralized automatic radiation monitoring system developed 20 years ago has recently been improved to monitor low level gamma radiation more accurately in normal operation of the nuclear facilities and to detect abnormal radioactive releases more effectively. The present state of the system is described. This system puts together environmental monitoring data such as gamma exposure rate (20 points), radioactive concentration in the air (4 points) and in water (2 drains), and meteorological items (14 including wind directions, wind speeds, solar radiation and air temperatures at a observation tower of 40 m height). Environmental monitoring around the JAERI site is carried out effectively using the system. Data processing system consists of a central processing unit, a magnetic disk, a magnetic tape, a line printer and a console typewriter. The data at respective monitoring points are transmitted to the central monitoring room by wireless or telephone line. All data are printed out and field in magnetic disk and magnetic tape every 10 minutes. When the emergency levels are exceeded, however, the data are automatically output on a line printer every 2 minute. This system can distinguish very low gamma exposure due to gaseous effluents, about 1 mR/y, from the background. Even in monthly exposures, calculated values based on the data of release amount and meteorology are in good agreement with the measured ones. (author)

Overnight hypoxic exposure and glucagon-like peptide-1 and leptin levels in humans

DEFF Research Database (Denmark)

Snyder, Eric M; Carr, Richard D; Deacon, Carolyn F

2008-01-01

increases with hypoxia; however, the influence of hypoxia on GLP-1 has not been studied in animals or humans to date. We sought to determine the influence of normobaric hypoxia on plasma leptin and GLP-1 levels in 25 healthy humans. Subjects ingested a control meal during normoxia and after 17 h of exposure...

Phototoxicity and oxidative stress responses in Daphnia magna under exposure to sulfathiazole and environmental level ultraviolet B irradiation

Energy Technology Data Exchange (ETDEWEB)

Kim, Jungkon [School of Public Health, Seoul National University, Seoul, 110-799 (Korea, Republic of)], E-mail: koguma@snu.ac.kr; Park, Yena [School of Public Health, Seoul National University, Seoul, 110-799 (Korea, Republic of)], E-mail: elohim@snu.ac.kr; Choi, Kyungho [School of Public Health, Seoul National University, Seoul, 110-799 (Korea, Republic of)], E-mail: kyungho@snu.ac.kr

2009-01-18

Sulfonamide antibiotics frequently occur in aquatic environments. In this study, phototoxicity of sulfathiazole (STZ) and its mechanism of action were investigated using Daphnia magna. We evaluated the changes of molecular level stress responses by assessing gene expression, enzyme induction and lipid peroxidation, and the related organism-level effects in D. magna. In the presence of ultraviolet B (UV-B) light (continuous irradiation with 13.8 {+-} 1.0 {mu}W cm{sup -2} d{sup -1}), STZ (at the nominal concentration of 94.9 mg/L) caused a significant increase in reactive oxygen species (ROS) generation and lipid peroxidation. Catalase (CAT) and glutathione S-transferase (GST) showed concentration-dependent increases caused by the exposure. Exposure to STZ and UV-B light caused apparent up-regulation of {alpha}-esterase, hemoglobin, and vitellogenin mRNA. The survival of daphnids was significantly affected by the co-exposure to STZ and UV-B. The biochemical and molecular level observations in combination with organism-level effects suggest that the phototoxicity of STZ was mediated in part by ROS generated by oxidative stress in D. magna.

Phototoxicity and oxidative stress responses in Daphnia magna under exposure to sulfathiazole and environmental level ultraviolet B irradiation

International Nuclear Information System (INIS)

Kim, Jungkon; Park, Yena; Choi, Kyungho

2009-01-01

Sulfonamide antibiotics frequently occur in aquatic environments. In this study, phototoxicity of sulfathiazole (STZ) and its mechanism of action were investigated using Daphnia magna. We evaluated the changes of molecular level stress responses by assessing gene expression, enzyme induction and lipid peroxidation, and the related organism-level effects in D. magna. In the presence of ultraviolet B (UV-B) light (continuous irradiation with 13.8 ± 1.0 μW cm -2 d -1 ), STZ (at the nominal concentration of 94.9 mg/L) caused a significant increase in reactive oxygen species (ROS) generation and lipid peroxidation. Catalase (CAT) and glutathione S-transferase (GST) showed concentration-dependent increases caused by the exposure. Exposure to STZ and UV-B light caused apparent up-regulation of α-esterase, hemoglobin, and vitellogenin mRNA. The survival of daphnids was significantly affected by the co-exposure to STZ and UV-B. The biochemical and molecular level observations in combination with organism-level effects suggest that the phototoxicity of STZ was mediated in part by ROS generated by oxidative stress in D. magna

Low Level Laser Therapy Reduces the Development of Lung Inflammation Induced by Formaldehyde Exposure.

Directory of Open Access Journals (Sweden)

Cristiane Miranda da Silva

Full Text Available Lung diseases constitute an important public health problem and its growing level of concern has led to efforts for the development of new therapies, particularly for the control of lung inflammation. Low Level Laser Therapy (LLLT has been highlighted as a non-invasive therapy with few side effects, but its mechanisms need to be better understood and explored. Considering that pollution causes several harmful effects on human health, including lung inflammation, in this study, we have used formaldehyde (FA, an environmental and occupational pollutant, for the induction of neutrophilic lung inflammation. Our objective was to investigate the local and systemic effects of LLLT after FA exposure. Male Wistar rats were exposed to FA (1% or vehicle (distillated water during 3 consecutive days and treated or not with LLLT (1 and 5 hours after each FA exposure. Non-manipulated rats were used as control. 24 h after the last FA exposure, we analyzed the local and systemic effects of LLLT. The treatment with LLLT reduced the development of neutrophilic lung inflammation induced by FA, as observed by the reduced number of leukocytes, mast cells degranulated, and a decreased myeloperoxidase activity in the lung. Moreover, LLLT also reduced the microvascular lung permeability in the parenchyma and the intrapulmonary bronchi. Alterations on the profile of inflammatory cytokines were evidenced by the reduced levels of IL-6 and TNF-α and the elevated levels of IL-10 in the lung. Together, our results showed that LLLT abolishes FA-induced neutrophilic lung inflammation by a reduction of the inflammatory cytokines and mast cell degranulation. This study may provide important information about the mechanisms of LLLT in lung inflammation induced by a pollutant.