76 FR 25236 - Carbon Dioxide; Exemption From the Requirement of a Tolerance

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-04

... metabolism and is always present in the body at about 6 percent concentration. An average adult human will... Departure/Levels of Concern Considering its presence in the environment and in the human body, the... the amount of carbon dioxide naturally produced by the human body each day. 2. Non-dietary exposure...

Rodent carcinogens: Setting priorities

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

Gold, L.S.; Slone, T.H.; Stern, B.R.

1992-10-09

The human diet contains an enormous background of natural chemicals, such as plant pesticides and the products of cooking, that have not been a focus of carcinogenicity testing. A broadened perspective that includes these natural chemicals is necessary. A comparison of possible hazards for 80 daily exposures to rodent carcinogens from a variety of sources is presented, using an index (HERP) that relates human exposure to carcinogenic potency in rodents. A similar ordering would be expected with the use of standard risk assessment methodology for the same human exposure values. Results indicate that, when viewed against the large background ofmore » naturally occurring carcinogens in typical portions of common foods, the residues of synthetic pesticides or environmental pollutants rank low. A similar result is obtained in a separate comparison of 32 average daily exposures to natural pesticides and synthetic pesticides residues in the diet. Although the findings do not indicate that these natural dietary carcinogens are important in human cancer, they cast doubt on the relative importance for human cancer of low-dose exposures to synthetic chemicals.« less

Reduction of Averaging Time for Evaluation of Human Exposure to Radiofrequency Electromagnetic Fields from Cellular Base Stations

NASA Astrophysics Data System (ADS)

Kim, Byung Chan; Park, Seong-Ook

In order to determine exposure compliance with the electromagnetic fields from a base station's antenna in the far-field region, we should calculate the spatially averaged field value in a defined space. This value is calculated based on the measured value obtained at several points within the restricted space. According to the ICNIRP guidelines, at each point in the space, the reference levels are averaged over any 6min (from 100kHz to 10GHz) for the general public. Therefore, the more points we use, the longer the measurement time becomes. For practical application, it is very advantageous to spend less time for measurement. In this paper, we analyzed the difference of average values between 6min and lesser periods and compared it with the standard uncertainty for measurement drift. Based on the standard deviation from the 6min averaging value, the proposed minimum averaging time is 1min.

Occupational exposure to NDMA and NMor in the European rubber industry.

PubMed

de Vocht, F; Burstyn, I; Straif, K; Vermeulen, R; Jakobsson, K; Nichols, L; Peplonska, B; Taeger, D; Kromhout, H

2007-03-01

Many nitrosamines are suspected of being human carcinogens, with the highest concentrations in the environment being measured in the rubber industry. Time trends of personal exposure to N-nitrosodimethylamine (NDMA) and to N-nitrosomorpholine (NMor) during the past two decades in the German rubber industry were analysed and compared with cross-sectional studies in the same period in the Netherlands, Poland, the UK and Sweden. In the majority of the surveyed departments exposures reduced over time, but considerable heterogeneity was present between departments and sectors. Significant reductions were primarily found in curing and post-treating departments and ranged from -3% year(-1) to -19% year(-1). In contrast, NDMA levels increased (+13% year(-1)) in maintenance and engineering in the tyres industry. Average NDMA-levels in general rubber goods (GRG) and NMor-levels in tyre production in Germany did not decrease significantly in the past two decades, whereas NDMA-levels in tyre production (-10% year(-1)) and NMor-levels in GRG (-7% year(-1)) declined significantly after the introduction of an exposure limit for total nitrosamines in Germany in 1988. Confidence intervals of average exposures in other studied countries largely overlap trends observed in Germany. Exposure to N-nitrosamines decreased on average two-to-five fold in the German rubber industry with comparable concentration levels in other European countries. Although average levels are well below the current limits exposure has not been eliminated, and incidental high exposures do still occur.

Indoor Exposures to PM2.5 IN a Rural Site of South India

NASA Astrophysics Data System (ADS)

Deepthi, Y.; Nagendra, S. S.

2016-12-01

Indian villages feature heavy biomass usage and presence of unpaved roads. Characteristics of indoor PM 2.5 concentrations under these distinctive features are very specific and the related studies are emerging as crucial prerequisites for formulating its regulatory norms. In this paper, we present the measurements of real-time indoor PM2.5 exposures for households of rural southern India. Indoor exposures were measured in three types of housing (Type A- Indoor kitchen without partition, Type B- Indoor kitchen with partition and Type C- Open air kitchen) for 6 days during the winter season of 2016. PM 2.5 mass concentrations were monitored using a 32-channel optical particle counter (Model 1.109, Grimm Labortechnik Ltd., Ainring, Germany) in the living rooms of the three houses. The sampling height maintained was 1.5 m above the ground level, which is the average human breathing height. Results indicated that the PM 2.5 exposure levels were very high in the houses with indoor kitchen facility with and without partitions (Types A and B). The diurnal averaged indoor PM 2.5 concentrations were above the human permissible limit (60 μg/m3) in the Type A (133±61 μg/m3) and Type B (81±26 μg/m3) houses. Whereas in the Type C house, the 24 hr averaged PM 2.5 concentrations were within the range of 55±5 μg/m3. During the cooking periods, the hourly averaged PM2.5 concentrations (1251, 292, 159 μg/m3 in Type A, B and C house, respectively) were more than one order higher than the diurnal averaged concentrations in all the three types of houses.

Determination of safety distance limits for a human near a cellular base station antenna, adopting the IEEE standard or ICNIRP guidelines.

PubMed

Cooper, Justin; Marx, Bernd; Buhl, Johannes; Hombach, Volker

2002-09-01

This paper investigates the minimum distance for a human body in the near field of a cellular telephone base station antenna for which there is compliance with the IEEE or ICNIRP threshold values for radio frequency electromagnetic energy absorption in the human body. First, local maximum specific absorption rates (SARs), measured and averaged over volumes equivalent to 1 and to 10 g tissue within the trunk region of a physical, liquid filled shell phantom facing and irradiated by a typical GSM 900 base station antenna, were compared to corresponding calculated SAR values. The calculation used a homogeneous Visible Human body model in front of a simulated base station antenna of the same type. Both real and simulated base station antennas operated at 935 MHz. Antenna-body distances were between 1 and 65 cm. The agreement between measurements and calculations was excellent. This gave confidence in the subsequent calculated SAR values for the heterogeneous Visible Human model, for which each tissue was assigned the currently accepted values for permittivity and conductivity at 935 MHz. Calculated SAR values within the trunk of the body were found to be about double those for the homogeneous case. When the IEEE standard and the ICNIRP guidelines are both to be complied with, the local SAR averaged over 1 g tissue was found to be the determining parameter. Emitted power values from the antenna that produced the maximum SAR value over 1 g specified in the IEEE standard at the base station are less than those needed to reach the ICNIRP threshold specified for the local SAR averaged over 10 g. For the GSM base station antenna investigated here operating at 935 MHz with 40 W emitted power, the model indicates that the human body should not be closer to the antenna than 18 cm for controlled environment exposure, or about 95 cm for uncontrolled environment exposure. These safe distance limits are for SARs averaged over 1 g tissue. The corresponding safety distance limits under the ICNIRP guidelines for SAR taken over 10 g tissue are 5 cm for occupational exposure and about 75 cm for general-public exposure. Copyright 2002 Wiley-Liss, Inc.

Use of real-time sensors to characterise human exposures to combustion related pollutants.

PubMed

Delgado-Saborit, Juana Maria

2012-07-01

Concentrations of black carbon and nitrogen dioxide have been collected concurrently using a MicrAeth AE-51 and an Aeroqual GSS NO(2) sensor. Forty five sampling events with a duration spanning between 16 and 22 hours have collected 10,800 5 min data in Birmingham (UK) from July to October 2011. The high temporal resolution database allowed identification of peak exposures and which activities contributed the most to these peaks, such as cooking and commuting. Personal exposure concentrations for non-occupationally exposed subjects ranged between 0.01 and 50 μg m(-3) for BC with average values of 1.3 ± 2.2 μg m(-3) (AM ± SD). Nitrogen dioxide exposure concentrations were in the range

High Throughput Heuristics for Prioritizing Human Exposure to ...

EPA Pesticide Factsheets

The risk posed to human health by any of the thousands of untested anthropogenic chemicals in our environment is a function of both the potential hazard presented by the chemical, and the possibility of being exposed. Without the capacity to make quantitative, albeit uncertain, forecasts of exposure, the putative risk of adverse health effect from a chemical cannot be evaluated. We used Bayesian methodology to infer ranges of exposure intakes that are consistent with biomarkers of chemical exposures identified in urine samples from the U.S. population by the National Health and Nutrition Examination Survey (NHANES). We perform linear regression on inferred exposure for demographic subsets of NHANES demarked by age, gender, and weight using high throughput chemical descriptors gleaned from databases and chemical structure-based calculators. We find that five of these descriptors are capable of explaining roughly 50% of the variability across chemicals for all the demographic groups examined, including children aged 6-11. For the thousands of chemicals with no other source of information, this approach allows rapid and efficient prediction of average exposure intake of environmental chemicals. The methods described by this manuscript provide a highly improved methodology for HTS of human exposure to environmental chemicals. The manuscript includes a ranking of 7785 environmental chemicals with respect to potential human exposure, including most of the Tox21 in vit

Time-varying cycle average and daily variation in ambient air pollution and fecundability.

PubMed

Nobles, Carrie J; Schisterman, Enrique F; Ha, Sandie; Buck Louis, Germaine M; Sherman, Seth; Mendola, Pauline

2018-01-01

Does ambient air pollution affect fecundability? While cycle-average air pollution exposure was not associated with fecundability, we observed some associations for acute exposure around ovulation and implantation with fecundability. Ambient air pollution exposure has been associated with adverse pregnancy outcomes and decrements in semen quality. The LIFE study (2005-2009), a prospective time-to-pregnancy study, enrolled 501 couples who were followed for up to one year of attempting pregnancy. Average air pollutant exposure was assessed for the menstrual cycle before and during the proliferative phase of each observed cycle (n = 500 couples; n = 2360 cycles) and daily acute exposure was assessed for sensitive windows of each observed cycle (n = 440 couples; n = 1897 cycles). Discrete-time survival analysis modeled the association between fecundability and an interquartile range increase in each pollutant, adjusting for co-pollutants, site, age, race/ethnicity, parity, body mass index, smoking, income and education. Cycle-average air pollutant exposure was not associated with fecundability. In acute models, fecundability was diminished with exposure to ozone the day before ovulation and nitrogen oxides 8 days post ovulation (fecundability odds ratio [FOR] 0.83, 95% confidence interval [CI]: 0.72, 0.96 and FOR 0.84, 95% CI: 0.71, 0.99, respectively). However, particulate matter ≤10 microns 6 days post ovulation was associated with greater fecundability (FOR 1.25, 95% CI: 1.01, 1.54). Although our study was unlikely to be biased due to confounding, misclassification of air pollution exposure and the moderate study size may have limited our ability to detect an association between ambient air pollution and fecundability. While no associations were observed for cycle-average ambient air pollution exposure, consistent with past research in the United States, exposure during critical windows of hormonal variability was associated with prospectively measured couple fecundability, warranting further investigation. This work was supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (Longitudinal Investigation of Fertility and the Environment study contract nos. #N01-HD-3-3355, NO1-HD-#-3356, N01-HD-3-3358 and the Air Quality and Reproductive Health Study Contract No. HHSN275200800002I, Task Order No. HHSN27500008). We declare no conflict of interest. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology 2017. This work is written by (a) US Government employee(s) and is in the public domain in the US.

Estimation of the whole-body averaged SAR of grounded human models for plane wave exposure at respective resonance frequencies.

PubMed

Hirata, Akimasa; Yanase, Kazuya; Laakso, Ilkka; Chan, Kwok Hung; Fujiwara, Osamu; Nagaoka, Tomoaki; Watanabe, Soichi; Conil, Emmanuelle; Wiart, Joe

2012-12-21

According to the international guidelines, the whole-body averaged specific absorption rate (WBA-SAR) is used as a metric of basic restriction for radio-frequency whole-body exposure. It is well known that the WBA-SAR largely depends on the frequency of the incident wave for a given incident power density. The frequency at which the WBA-SAR becomes maximal is called the 'resonance frequency'. Our previous study proposed a scheme for estimating the WBA-SAR at this resonance frequency based on an analogy between the power absorption characteristic of human models in free space and that of a dipole antenna. However, a scheme for estimating the WBA-SAR in a grounded human has not been discussed sufficiently, even though the WBA-SAR in a grounded human is larger than that in an ungrounded human. In this study, with the use of the finite-difference time-domain method, the grounded condition is confirmed to be the worst-case exposure for human body models in a standing posture. Then, WBA-SARs in grounded human models are calculated at their respective resonant frequencies. A formula for estimating the WBA-SAR of a human standing on the ground is proposed based on an analogy with a quarter-wavelength monopole antenna. First, homogenized human body models are shown to provide the conservative WBA-SAR as compared with anatomically based models. Based on the formula proposed here, the WBA-SARs in grounded human models are approximately 10% larger than those in free space. The variability of the WBA-SAR was shown to be ±30% even for humans of the same age, which is caused by the body shape.

Baseline repeated measures from controlled human exposure studies: associations between ambient air pollution exposure and the systemic inflammatory biomarkers IL-6 and fibrinogen.

PubMed

Thompson, Aaron M S; Zanobetti, Antonella; Silverman, Frances; Schwartz, Joel; Coull, Brent; Urch, Bruce; Speck, Mary; Brook, Jeffrey R; Manno, Michael; Gold, Diane R

2010-01-01

Systemic inflammation may be one of the mechanisms mediating the association between ambient air pollution and cardiovascular morbidity and mortality. Interleukin-6 (IL-6) and fibrinogen are biomarkers of systemic inflammation that are independent risk factors for cardio-vascular disease. We investigated the association between ambient air pollution and systemic inflammation using baseline measurements of IL-6 and fibrinogen from controlled human exposure studies. In this retrospective analysis we used repeated-measures data in 45 nonsmoking subjects. Hourly and daily moving averages were calculated for ozone, nitrogen dioxide, sulfur dioxide, and particulate matter

Tracking natural and anthropogenic Pb exposure to its geological source.

PubMed

Evans, Jane; Pashley, Vanessa; Madgwick, Richard; Neil, Samantha; Chenery, Carolyn

2018-01-31

Human Pb exposure comes from two sources: (i) natural uptake through ingestion of soils and typified by populations that predate mining activity and (ii) anthropogenic exposure caused by the exposure to Pb derived from ore deposits. Currently, the measured concentration of Pb within a sample is used to discriminate between these two exposure routes, with the upper limit for natural exposure in skeletal studies given as 0.5 or 0.7 mg/kg in enamel and 0.5/0.7 μg/dL in blood. This threshold approach to categorising Pb exposure does not distinguish between the geological origins of the exposure types. However, Pb isotopes potentially provide a more definitive means of discriminating between sources. Whereas Pb from soil displays a crustal average 238 U/ 204 Pb (μ) value of c 9.7, Pb from ore displays a much wider range of evolution pathways. These characteristics are transferred into tooth enamel, making it possible to characterize human Pb exposure in terms of the primary source of ingested Pb and to relate mining activity to geotectonic domains. We surmise that this ability to discriminate between silicate and sulphide Pb exposure will lead to a better understanding of the evolution of early human mining activity and development of exposure models through the Anthropocene.

Bioaccessibility and human health risk assessment of lead in soil from Daye City

NASA Astrophysics Data System (ADS)

Li, Q.; Li, F.; Xiao, M. S.; Cai, Y.; Xiong, L.; Huang, J. B.; Fu, J. T.

2018-01-01

Lead (Pb) in soil from 4 sampling sites of Daye City was studied. Bioaccessibilities of Pb in soil were determined by the method of simplified bioaccessible extraction test (SBET). Since traditional health risk assessment was built on the basis of metal total content, the risk may be overestimated. Modified human health risk assessment model considering bioaccessibility was built in this study. Health risk of adults and children exposure to Pb based on total contents and bioaccessible contents were evaluated. The results showed that bioaccessible content of Pb in soil was much lower than its total content, and the average bioaccessible factor (BF) was only 25.37%. The hazard indexes (HIs) for adults and children calculated by two methods were all lower than 1. It indicated that there were no no-carcinogenic risks of Pb for human in Daye. By comparing with the results, the average bioaccessible HIs for adults and children were lower than the total one, which was due to the lower hazard quotient (HQ). Proportions of non-carcinogenic risk exposure to Pb via different pathways have also changed. Particularly, the most main risk exposure pathway for adults turned from the oral ingestion to the inhalation.

Induced electric fields in workers near low-frequency induction heating machines.

PubMed

Kos, Bor; Valič, Blaž; Kotnik, Tadej; Gajšek, Peter

2014-04-01

Published data on occupational exposure to induction heating equipment are scarce, particularly in terms of induced quantities in the human body. This article provides some additional information by investigating exposure to two such machines-an induction furnace and an induction hardening machine. Additionally, a spatial averaging algorithm for measured fields we developed in a previous publication is tested on new data. The human model was positioned at distances where measured values of magnetic flux density were above the reference levels. All human exposure was below the basic restriction-the lower bound of the 0.1 top percentile induced electric field in the body of a worker was 0.193 V/m at 30 cm from the induction furnace. © 2013 Wiley Periodicals, Inc.

On the averaging area for incident power density for human exposure limits at frequencies over 6 GHz

NASA Astrophysics Data System (ADS)

Hashimoto, Yota; Hirata, Akimasa; Morimoto, Ryota; Aonuma, Shinta; Laakso, Ilkka; Jokela, Kari; Foster, Kenneth R.

2017-04-01

Incident power density is used as the dosimetric quantity to specify the restrictions on human exposure to electromagnetic fields at frequencies above 3 or 10 GHz in order to prevent excessive temperature elevation at the body surface. However, international standards and guidelines have different definitions for the size of the area over which the power density should be averaged. This study reports computational evaluation of the relationship between the size of the area over which incident power density is averaged and the local peak temperature elevation in a multi-layer model simulating a human body. Three wave sources are considered in the frequency range from 3 to 300 GHz: an ideal beam, a half-wave dipole antenna, and an antenna array. 1D analysis shows that averaging area of 20 mm  ×  20 mm is a good measure to correlate with the local peak temperature elevation when the field distribution is nearly uniform in that area. The averaging area is different from recommendations in the current international standards/guidelines, and not dependent on the frequency. For a non-uniform field distribution, such as a beam with small diameter, the incident power density should be compensated by multiplying a factor that can be derived from the ratio of the effective beam area to the averaging area. The findings in the present study suggest that the relationship obtained using the 1D approximation is applicable for deriving the relationship between the incident power density and the local temperature elevation.

Preparation and performance features of wristband samplers and considerations for chemical exposure assessment

PubMed Central

Anderson, Kim A; Points, Gary L; Donald, Carey E; Dixon, Holly M; Scott, Richard P; Wilson, Glenn; Tidwell, Lane G; Hoffman, Peter D; Herbstman, Julie B; O'Connell, Steven G

2017-01-01

Wristbands are increasingly used for assessing personal chemical exposures. Unlike some exposure assessment tools, guidelines for wristbands, such as preparation, applicable chemicals, and transport and storage logistics, are lacking. We tested the wristband’s capacity to capture and retain 148 chemicals including polychlorinated biphenyls (PCBs), pesticides, flame retardants, polycyclic aromatic hydrocarbons (PAHs), and volatile organic chemicals (VOCs). The chemicals span a wide range of physical–chemical properties, with log octanol–air partitioning coefficients from 2.1 to 13.7. All chemicals were quantitatively and precisely recovered from initial exposures, averaging 102% recovery with relative SD ≤21%. In simulated transport conditions at +30 °C, SVOCs were stable up to 1 month (average: 104%) and VOC levels were unchanged (average: 99%) for 7 days. During long-term storage at −20 °C up to 3 (VOCs) or 6 months (SVOCs), all chemical levels were stable from chemical degradation or diffusional losses, averaging 110%. Applying a paired wristband/active sampler study with human participants, the first estimates of wristband–air partitioning coefficients for PAHs are presented to aid in environmental air concentration estimates. Extrapolation of these stability results to other chemicals within the same physical–chemical parameters is expected to yield similar results. As we better define wristband characteristics, wristbands can be better integrated in exposure science and epidemiological studies. PMID:28745305

Civil Conflict and Human Capital Accumulation: The Long-Term Effects of Political Violence in Peru

ERIC Educational Resources Information Center

Leon, Gianmarco

2012-01-01

This paper provides empirical evidence of the persistent effect of exposure to political violence on human capital accumulation. I exploit the variation in conflict location and birth cohorts to identify the long- and short-term effects of the civil war on educational attainment. Conditional on being exposed to violence, the average person…

Environmental impact and human exposure to PCBs in Guiyu, an electronic waste recycling site in China.

PubMed

Xing, Guan Hua; Chan, Janet Kit Yan; Leung, Anna Oi Wah; Wu, Sheng Chun; Wong, M H

2009-01-01

PCB levels in fish (collected from local rivers), atmosphere and human milk samples have been studied to determine the exposure levels of PCBs for local residents and e-waste workers in Guiyu, a major electronic waste scrapping center in China. The source appointment and correlation analyses showed that homologue composition of PCBs in 7 species of fish were consistent and similar to commercial PCBs Aroclor 1248. PCB levels in air surrounding the open burning site were significantly higher than those in residential area. Inhalation exposure contributed 27% and 93% to the total body loadings (the sum of dietary and inhalation exposure) of the local residents, and e-waste workers engaged in open burning respectively. Total PCB concentrations in human milk ranged from N.D. to 57.6 ng/g lipid, with an average of 9.50 ng/g lipid. The present results indicated that commercial PCBs derived from e-waste recycling are major sources of PCBs accumulating in different environmental media, leading to the accumulation of high chlorinated biphenyls in human beings.

Managing risks of noncancer health effects at hazardous waste sites: A case study using the Reference Concentration (RfC) of trichloroethylene (TCE).

PubMed

Dourson, Michael L; Gadagbui, Bernard K; Thompson, Rod B; Pfau, Edward J; Lowe, John

2016-10-01

A method for determining a safety range for non-cancer risks is proposed, similar in concept to the range used for cancer in the management of waste sites. This safety range brings transparency to the chemical specific Reference Dose or Concentration by replacing their "order of magnitude" definitions with a scientifically-based range. EPA's multiple RfCs for trichloroethylene (TCE) were evaluated as a case study. For TCE, a multi-endpoint safety range was judged to be 3 μg/m(3) to 30 μg/m,(3) based on a review of kidney effects found in NTP (1988), thymus effects found in Keil et al. (2009) and cardiac effects found in the Johnson et al. (2003) study. This multi-endpoint safety range is derived from studies for which the appropriate averaging time corresponds to different exposure durations, and, therefore, can be applied to both long- and short-term exposures with appropriate consideration of exposure averaging times. For shorter-term exposures, averaging time should be based on the time of cardiac development in humans during fetal growth, an average of approximately 20-25 days. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

On the safety assessment of human exposure in the proximity of cellular communications base-station antennas at 900, 1800 and 2170 MHz.

PubMed

Martínez-Búrdalo, M; Martín, A; Anguiano, M; Villar, R

2005-09-07

In this work, the procedures for safety assessment in the close proximity of cellular communications base-station antennas at three different frequencies (900, 1800 and 2170 MHz) are analysed. For each operating frequency, we have obtained and compared the distances to the antenna from the exposure places where electromagnetic fields are below reference levels and the distances where the specific absorption rate (SAR) values in an exposed person are below the basic restrictions, according to the European safety guidelines. A high-resolution human body model has been located, in front of each base-station antenna as a worst case, at different distances, to compute whole body averaged SAR and maximum 10 g averaged SAR inside the exposed body. The finite-difference time-domain method has been used for both electromagnetic fields and SAR calculations. This paper shows that, for antenna-body distances in the near zone of the antenna, the fact that averaged field values be below the reference levels could, at certain frequencies, not guarantee guidelines compliance based on basic restrictions.

Estimated Daily Average Per Capita Water Ingestion by Child and Adult Age Categories Based on USDA's 1994-96 and 1998 Continuing Survey of Food Intakes by Individuals (Journal Article)

EPA Science Inventory

Current water ingestion estimates are important for the assessment of risk to human populations of exposure to water-borne pollutants. This paper reports mean and percentile estimates of the distributions of daily average per capita water ingestion for 12 age range groups. The a...

Model Averaging for Predicting the Exposure to Aflatoxin B1 Using DNA Methylation in White Blood Cells of Infants

NASA Astrophysics Data System (ADS)

Rahardiantoro, S.; Sartono, B.; Kurnia, A.

2017-03-01

In recent years, DNA methylation has been the special issue to reveal the pattern of a lot of human diseases. Huge amount of data would be the inescapable phenomenon in this case. In addition, some researchers interesting to take some predictions based on these huge data, especially using regression analysis. The classical approach would be failed to take the task. Model averaging by Ando and Li [1] could be an alternative approach to face this problem. This research applied the model averaging to get the best prediction in high dimension of data. In the practice, the case study by Vargas et al [3], data of exposure to aflatoxin B1 (AFB1) and DNA methylation in white blood cells of infants in The Gambia, take the implementation of model averaging. The best ensemble model selected based on the minimum of MAPE, MAE, and MSE of predictions. The result is ensemble model by model averaging with number of predictors in model candidate is 15.

Minireview on the toxicity of dietary acrylamide.

PubMed

Parzefall, Wolfram

2008-04-01

Acrylamide is a commodity chemical with many industrial and laboratory uses. It is also formed from carbohydrate and amino acid containing food by heating (primarily in fried potato products, bread, coffee). Neurotoxicity was detected as the primary toxic effect after occupational exposure. In rats and mice AA is toxic for reproduction and development and to male germ cells, is genotoxic through a reactive metabolite, glycidamide, and carcinogenic to several organs. Epidemiological studies did not point to an association between either occupational or dietary exposure and an excess of cancer incidence. Health risks of the general population are based on an average exposure to 1 microg/kg bw/day increasing for high consumers to 4 microg/kg bw/day. For average consumers a margin of exposure of 200 for neurotoxicity can be regarded as sufficiently protective. However, a margin of 300 for carcinogenic risks appears not sufficient when applying a precautionary principle. This is also illustrated when the benchmark dose lower confidence limit for cancer is divided by an uncertainty factor of 300, which arrives at a tolerable daily intake of 1 microg/kg bw/day, and thus is in the range of average consumption. Further measures to minimize acrylamide formation in food should therefore be explored to reduce human exposure.

The role of temporal context in norm-based encoding of faces.

PubMed

Van Rensbergen, Bram; Op de Beeck, Hans P

2014-02-01

Research shows that the human brain encodes faces in terms of how they relate to a prototypical face, a phenomenon referred to as norm-based encoding. The goal of this study was to examine the effect of short-term exposure on the development of the norm, independently of global, long-term exposure. We achieved this by varying the sequence of presentation of the stimuli while keeping global exposure constant. We found that a systematic manipulation of the average face in a set of 10 preceding trials can shift this norm toward that average. However, there was no effect of order or recency among these trials; thus, there was no evidence that the last faces mattered more than the first. This suggests that the position of the face norm is modified by information that is integrated across multiple recent faces.

Ultra-trace measurement of Dechloranes to investigate food as a route of human exposure.

PubMed

L'Homme, Benjamin; Calaprice, Chiara; Calvano, Cosima Damiana; Zambonin, Carlo; Leardi, Riccardo; Focant, Jean-François

2015-11-01

Dechloranes, including Dechlorane Plus (syn- and anti-isomers), Dechlorane 602, Dechlorane 603, Dechlorane 604, Chlordene Plus, and Mirex are used as flame-retardants and were recently found in human serum of the European population. In order to investigate if food consumption would possibly be a significant route of exposure, we developed a method for the measurement of Dechloranes in food and feed. We showed that it was possible to extend the scope of the regular polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin like (DL-), and non-dioxin like (NDL-) regulated PCBs clean-up and fractionation procedure to Dechloranes and that no compound degradation occurred during the strong acidic treatments used for lipid digestion. Dechloranes were measured by gas chromatography coupled to triple quadrupole mass spectrometry (GC-QQQMS/MS). We optimized injection parameters by face centered experimental design (FCD). The electron ionization fragmentation was investigated to set appropriate multiple reaction monitoring (MRM) transitions. Instrumental and method limits of quantitation (iLOQs and mLOQs) were determined following EU guidelines for dioxin analyses in food. A total of 88 samples were analyzed to assess the prevalence of this route of exposure to humans. Average levels of the sum of Dechloranes ranged from 10 to 31pg/g fat, with the exception of fish, feed additives, and corn that were reported in pg/g wet weight at average levels of 9, 12, and 2pg/g ww. Based on Belgian food habits, a dietary intake was estimated to be 136pg/day. The relatively low reported levels indicate that other routes of human exposure should be considered. Copyright © 2015 Elsevier Ltd. All rights reserved.

Empirical Bayes Gaussian likelihood estimation of exposure distributions from pooled samples in human biomonitoring.

PubMed

Li, Xiang; Kuk, Anthony Y C; Xu, Jinfeng

2014-12-10

Human biomonitoring of exposure to environmental chemicals is important. Individual monitoring is not viable because of low individual exposure level or insufficient volume of materials and the prohibitive cost of taking measurements from many subjects. Pooling of samples is an efficient and cost-effective way to collect data. Estimation is, however, complicated as individual values within each pool are not observed but are only known up to their average or weighted average. The distribution of such averages is intractable when the individual measurements are lognormally distributed, which is a common assumption. We propose to replace the intractable distribution of the pool averages by a Gaussian likelihood to obtain parameter estimates. If the pool size is large, this method produces statistically efficient estimates, but regardless of pool size, the method yields consistent estimates as the number of pools increases. An empirical Bayes (EB) Gaussian likelihood approach, as well as its Bayesian analog, is developed to pool information from various demographic groups by using a mixed-effect formulation. We also discuss methods to estimate the underlying mean-variance relationship and to select a good model for the means, which can be incorporated into the proposed EB or Bayes framework. By borrowing strength across groups, the EB estimator is more efficient than the individual group-specific estimator. Simulation results show that the EB Gaussian likelihood estimates outperform a previous method proposed for the National Health and Nutrition Examination Surveys with much smaller bias and better coverage in interval estimation, especially after correction of bias. Copyright © 2014 John Wiley & Sons, Ltd.

77 FR 34302 - Approval and Promulgation of Implementation Plans; Tennessee: Prevention of Significant...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-06-11

... the average width of a human hair) are considered to be ``fine particles'' and are also known as PM 2... various chemical reactions. The health effects associated with exposure to PM 2.5 include potential...

Concentration and Risk Evaluation of Polycyclic Aromatic Hydrocarbons in Urban Soil in the Typical Semi-Arid City of Xi'an in Northwest China.

PubMed

Wang, Lijun; Zhang, Shengwei; Wang, Li; Zhang, Wenjuan; Shi, Xingmin; Lu, Xinwei; Li, Xiaoping; Li, Xiaoyun

2018-03-27

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, presenting potential threats to the ecological environment and human health. Sixty-two urban soil samples were collected in the typical semi-arid city of Xi'an in Northwest China. They were analyzed for concentration, pollution, and ecological and health risk of sixteen U.S. Environmental Protection Agency priority PAHs. The total concentrations of the sixteen PAHs (Σ16PAHs) in the urban soil ranged from 390.6 to 10,652.8 µg/kg with an average of 2052.6 µg/kg. The concentrations of some individual PAHs in the urban soil exceeded Dutch Target Values of Soil Quality and the Σ16PAHs represented heavy pollution. Pyrene and dibenz[a,h]anthracene had high ecological risk to aquatic/soil organisms, while other individual PAHs showed low ecological risk. The total ecological risk of PAHs to aquatic/soil organisms is classified as moderate. Toxic equivalency quantities (TEQs) of the sixteen PAHs varied between 21.16 and 1625.78 µg/kg, with an average of 423.86 µg/kg, indicating a relatively high toxicity potential. Ingestion and dermal adsorption of soil dust were major pathways of human exposure to PAHs from urban soil. Incremental lifetime cancer risks (ILCRs) of human exposure to PAHs were 2.86 × 10 -5 for children and 2.53 × 10 -5 for adults, suggesting that the cancer risk of human exposure to PAHs from urban soil is acceptable.

Understanding the exposure-time effect on speckle contrast measurements for laser displays

NASA Astrophysics Data System (ADS)

Suzuki, Koji; Kubota, Shigeo

2018-02-01

To evaluate the influence of exposure time on speckle noise for laser displays, speckle contrast measurement method was developed observable at a human eye response time using a high-sensitivity camera which has a signal multiplying function. The nonlinearity of camera light sensitivity was calibrated to measure accurate speckle contrasts, and the measuring lower limit noise of speckle contrast was improved by applying spatial-frequency low pass filter to the captured images. Three commercially available laser displays were measured over a wide range of exposure times from tens of milliseconds to several seconds without adjusting the brightness of laser displays. The speckle contrast of raster-scanned mobile projector without any speckle-reduction device was nearly constant over various exposure times. On the contrary to this, in full-frame projection type laser displays equipped with a temporally-averaging speckle-reduction device, some of their speckle contrasts close to the lower limits noise were slightly increased at the shorter exposure time due to the noise. As a result, the exposure-time effect of speckle contrast could not be observed in our measurements, although it is more reasonable to think that the speckle contrasts of laser displays, which are equipped with the temporally-averaging speckle-reduction device, are dependent on the exposure time. This discrepancy may be attributed to the underestimation of temporal averaging factor. We expected that this method is useful for evaluating various laser displays and clarify the relationship between the speckle noise and the exposure time for a further verification of speckle reduction.

MODELING OF HUMAN EXPOSURE TO IN-VEHICLE PM2.5 FROM ENVIRONMENTAL TOBACCO SMOKE

PubMed Central

Cao, Ye; Frey, H. Christopher

2012-01-01

Environmental tobacco smoke (ETS) is estimated to be a significant contributor to in-vehicle human exposure to fine particulate matter of 2.5 µm or smaller (PM2.5). A critical assessment was conducted of a mass balance model for estimating PM2.5 concentration with smoking in a motor vehicle. Recommendations for the range of inputs to the mass-balance model are given based on literature review. Sensitivity analysis was used to determine which inputs should be prioritized for data collection. Air exchange rate (ACH) and the deposition rate have wider relative ranges of variation than other inputs, representing inter-individual variability in operations, and inter-vehicle variability in performance, respectively. Cigarette smoking and emission rates, and vehicle interior volume, are also key inputs. The in-vehicle ETS mass balance model was incorporated into the Stochastic Human Exposure and Dose Simulation for Particulate Matter (SHEDS-PM) model to quantify the potential magnitude and variability of in-vehicle exposures to ETS. The in-vehicle exposure also takes into account near-road incremental PM2.5 concentration from on-road emissions. Results of probabilistic study indicate that ETS is a key contributor to the in-vehicle average and high-end exposure. Factors that mitigate in-vehicle ambient PM2.5 exposure lead to higher in-vehicle ETS exposure, and vice versa. PMID:23060732

Mass spectrometry profiling of oxylipins, endocannabinoids, and N-acylethanolamines in human lung lavage fluids reveals responsiveness of prostaglandin E2 and associated lipid metabolites to biodiesel exhaust exposure.

PubMed

Gouveia-Figueira, Sandra; Karimpour, Masoumeh; Bosson, Jenny A; Blomberg, Anders; Unosson, Jon; Pourazar, Jamshid; Sandström, Thomas; Behndig, Annelie F; Nording, Malin L

2017-04-01

The adverse effects of petrodiesel exhaust exposure on the cardiovascular and respiratory systems are well recognized. While biofuels such as rapeseed methyl ester (RME) biodiesel may have ecological advantages, the exhaust generated may cause adverse health effects. In the current study, we investigated the responses of bioactive lipid mediators in human airways after biodiesel exhaust exposure using lipidomic profiling methods. Lipid mediator levels in lung lavage were assessed following 1-h biodiesel exhaust (average particulate matter concentration, 159 μg/m 3 ) or filtered air exposure in 15 healthy individuals in a double-blinded, randomized, controlled, crossover study design. Bronchoscopy was performed 6 h post exposure and lung lavage fluids, i.e., bronchial wash (BW) and bronchoalveolar lavage (BAL), were sequentially collected. Mass spectrometry methods were used to detect a wide array of oxylipins (including eicosanoids), endocannabinoids, N-acylethanolamines, and related lipid metabolites in the collected BW and BAL samples. Six lipids in the human lung lavage samples were altered following biodiesel exhaust exposure, three from BAL samples and three from BW samples. Of these, elevated levels of PGE 2 , 12,13-DiHOME, and 13-HODE, all of which were found in BAL samples, reached Bonferroni-corrected significance. This is the first study in humans reporting responses of bioactive lipids following biodiesel exhaust exposure and the most pronounced responses were seen in the more peripheral and alveolar lung compartments, reflected by BAL collection. Since the responsiveness and diagnostic value of a subset of the studied lipid metabolites were established in lavage fluids, we conclude that our mass spectrometry profiling method is useful to assess effects of human exposure to vehicle exhaust.

Tire tread wear particles in ambient air--a previously unknown source of human exposure to the biocide 2-mercaptobenzothiazole.

PubMed

Avagyan, Rozanna; Sadiktsis, Ioannis; Bergvall, Christoffer; Westerholm, Roger

2014-10-01

Urban particulate matter (PM), asphalt, and tire samples were investigated for their content of benzothiazole and benzothiazole derivates. The purpose of this study was to examine whether wear particles, i.e., tire tread wear or road surface wear, could contribute to atmospheric concentrations of benzothiazole derivatives. Airborne particulate matter (PM10) sampled at a busy street in Stockholm, Sweden, contained on average 17 pg/m(3) benzothiazole and 64 pg/m(3) 2-mercaptobenzothiazole, and the total suspended particulate-associated benzothiazole and 2-mercaptobenzothiazole concentrations were 199 and 591 pg/m(3), respectively. This indicates that tire tread wear may be a major source of these benzothiazoles to urban air PM in Stockholm. Furthermore, 2-mercaptobenzothiazole was determined in urban air particulates for the first time in this study, and its presence in inhalable PM10 implies that the human exposure to this biocide is underestimated. This calls for a revision of the risk assessments of 2-mercaptobenzothiazole exposure to humans which currently is limited to occupational exposure.

Acrylamide content in cigarette mainstream smoke and estimation of exposure to acrylamide from tobacco smoke in Poland.

PubMed

Mojska, Hanna; Gielecińska, Iwona; Cendrowski, Andrzej

2016-09-01

Acrylamide is a "probably human carcinogen" monomer that can form in heated starchy food as a result of a reaction between asparagine and reducing sugars via Maillard reaction. The main source of acrylamide in human diet are potato products, cereal products and coffee. Tobacco smoke may be another significant source of exposure to acrylamide. The aim of our study was to determine acrylamide content in cigarettes available on the Polish market and to estimate the exposure to acrylamide originating from tobacco smoke in smokers in Poland. The material was cigarettes of the top five brands bought in Poland and tobacco from non-smoked cigarettes. Acrylamide content in cigarettes mainstream smoke was determined by LC-MS/MS. Exposure assessment was carried out using analytical data of acrylamide content in cigarettes and the mean quantity of cigarettes smoked daily by smokers in Poland, assuming body weight at 70 kg. The mean content of acrylamide was 679.3 ng/cigarette (range: 455.0 - 822.5 ng/cigarette). The content of acrylamide was evidenced to correlate positively with total particulate matter (TPM) content in cigarettes. The estimated average exposure to acrylamide from tobacco smoke in adult smokers in Poland is 0.17 μg/kg b.w./day. Our results demonstrate that tobacco smoke is a significant source of acrylamide and total exposure to acrylamide in the population of smokers, on average, is higher by more than 50% in comparison with non-smokers. Our estimation of exposure to acrylamide from tobacco smoke is the first estimation taking into account the actual determined acrylamide content in the cigarettes available on the market.

Average absorption cross-section of the human body measured at 1-12 GHz in a reverberant chamber: results of a human volunteer study

NASA Astrophysics Data System (ADS)

Flintoft, I. D.; Robinson, M. P.; Melia, G. C. R.; Marvin, A. C.; Dawson, J. F.

2014-07-01

The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incidence of 60 ungrounded adult subjects was measured at microwave frequencies of 1-12 GHz in a reverberation chamber. Average ACS is important in non-ionizing dosimetry and exposure studies, and is closely related to the whole-body averaged specific absorption rate (WBSAR). The average ACS was measured with a statistical uncertainty of less than 3% and high frequency resolution for individuals with a range of body shapes and sizes allowing the statistical distribution of WBSAR over a real population with individual internal and external morphologies to be determined. The average ACS of all subjects was found to vary from 0.15 to 0.4 m2 for an individual subject it falls with frequency over 1-6 GHz, and then rises slowly over the 6-12 GHz range in which few other studies have been conducted. Average ACS and WBSAR are then used as a surrogate for worst-case ACS/WBSAR, in order to study their variability across a real population compared to literature results from simulations using numerical phantoms with a limited range of anatomies. Correlations with body morphological parameters such as height, mass and waist circumference have been investigated: the strongest correlation is with body surface area (BSA) at all frequencies above 1 GHz, however direct proportionality to BSA is not established until above 5 GHz. When the average ACS is normalized to the BSA, the resulting absorption efficiency shows a negative correlation with the estimated thickness of subcutaneous body fat. Surrogate models and statistical analysis of the measurement data are presented and compared to similar models from the literature. The overall dispersion of measured average WBSAR of the sample of the UK population studied is consistent with the dispersion of simulated worst-case WBSAR across multiple numerical phantom families. The statistical results obtained allow the calibration of human exposure assessments made with particular phantoms to a population with a range of individual morphologies.

Average absorption cross-section of the human body measured at 1-12 GHz in a reverberant chamber: results of a human volunteer study.

PubMed

Flintoft, I D; Robinson, M P; Melia, G C R; Marvin, A C; Dawson, J F

2014-07-07

The electromagnetic absorption cross-section (ACS) averaged over polarization and angle-of-incidence of 60 ungrounded adult subjects was measured at microwave frequencies of 1-12 GHz in a reverberation chamber. Average ACS is important in non-ionizing dosimetry and exposure studies, and is closely related to the whole-body averaged specific absorption rate (WBSAR). The average ACS was measured with a statistical uncertainty of less than 3% and high frequency resolution for individuals with a range of body shapes and sizes allowing the statistical distribution of WBSAR over a real population with individual internal and external morphologies to be determined. The average ACS of all subjects was found to vary from 0.15 to 0.4 m(2); for an individual subject it falls with frequency over 1-6 GHz, and then rises slowly over the 6-12 GHz range in which few other studies have been conducted. Average ACS and WBSAR are then used as a surrogate for worst-case ACS/WBSAR, in order to study their variability across a real population compared to literature results from simulations using numerical phantoms with a limited range of anatomies. Correlations with body morphological parameters such as height, mass and waist circumference have been investigated: the strongest correlation is with body surface area (BSA) at all frequencies above 1 GHz, however direct proportionality to BSA is not established until above 5 GHz. When the average ACS is normalized to the BSA, the resulting absorption efficiency shows a negative correlation with the estimated thickness of subcutaneous body fat. Surrogate models and statistical analysis of the measurement data are presented and compared to similar models from the literature. The overall dispersion of measured average WBSAR of the sample of the UK population studied is consistent with the dispersion of simulated worst-case WBSAR across multiple numerical phantom families. The statistical results obtained allow the calibration of human exposure assessments made with particular phantoms to a population with a range of individual morphologies.

Respiratory tract toxicity in rats exposed to Mexico City air.

PubMed

Moss, O R; Gross, E A; James, R A; Janszen, D B; Ross, P W; Roberts, K C; Howard, A M; Harkema, J R; Calderón-Garcidueñas, L; Morgan, K T

2001-03-01

The rat has been used extensively as a health sentinel, indicator, or monitor of environmental health hazards, but this model has not been directly validated against human exposures. Humans in Mexico City show upper respiratory tract lesions and evidence of pulmonary damage related to their environmental inhalation exposure. In this study, male and female F344 rats were exposed (23 hr/day) in Mexico City to local Mexico City air (MCA)* for up to seven weeks. Controls were maintained at the same location under filtered air. Prior to these exposures, several steps were taken. First, the nasal passages of normal male rats shipped from the United States and housed in Mexico City were examined for mycoplasma infection; no evidence of infection was found. In addition, a mobile exposure and monitoring system was assembled and, with an ozone (O3) exposure atmosphere, was tested along with supporting histopathology techniques and analysis of rat nasal and lung tissues. Last, the entire exposure model (equipment and animals) was transported to Mexico City and validated for a three-week period. During the seven-week study there were 18 one-hour intervals during which the average O3 concentration of MCA in the exposure chamber exceeded the US National Ambient Air Quality Standard (NAAQS) of 0.120 ppm 03 (hourly average, not to be exceeded more than once per year). This prolonged exposure of healthy F344 rats to MCA containing episodically low to moderate concentrations of 03 (as well as other urban air pollutants) did not induce inflammatory or epithelial lesions in the nasal airways or lung as measured by qualitative histologic techniques or quantitative morphometric techniques. These findings agree with those of previous controlled O3 inhalation studies, but they are in contrast to reports indicating that O3-polluted MCA causes significant nasal mucosal injury in adults and children living in southwestern Mexico City. Taken together, these findings may suggest that human airways are markedly more susceptible to the toxic effects of MCA than are the airways of the F344 rat.

PBPK-Based Probabilistic Risk Assessment for Total Chlorotriazines in Drinking Water

PubMed Central

Breckenridge, Charles B.; Campbell, Jerry L.; Clewell, Harvey J.; Andersen, Melvin E.; Valdez-Flores, Ciriaco; Sielken, Robert L.

2016-01-01

The risk of human exposure to total chlorotriazines (TCT) in drinking water was evaluated using a physiologically based pharmacokinetic (PBPK) model. Daily TCT (atrazine, deethylatrazine, deisopropylatrazine, and diaminochlorotriazine) chemographs were constructed for 17 frequently monitored community water systems (CWSs) using linear interpolation and Krieg estimates between observed TCT values. Synthetic chemographs were created using a conservative bias factor of 3 to generate intervening peaks between measured values. Drinking water consumption records from 24-h diaries were used to calculate daily exposure. Plasma TCT concentrations were updated every 30 minutes using the PBPK model output for each simulated calendar year from 2006 to 2010. Margins of exposure (MOEs) were calculated (MOE = [Human Plasma TCTPOD] ÷ [Human Plasma TCTEXP]) based on the toxicological point of departure (POD) and the drinking water-derived exposure to TCT. MOEs were determined based on 1, 2, 3, 4, 7, 14, 28, or 90 days of rolling average exposures and plasma TCT Cmax, or the area under the curve (AUC). Distributions of MOE were determined and the 99.9th percentile was used for risk assessment. MOEs for all 17 CWSs were >1000 at the 99.9th percentile. The 99.9th percentile of the MOE distribution was 2.8-fold less when the 3-fold synthetic chemograph bias factor was used. MOEs were insensitive to interpolation method, the consumer’s age, the water consumption database used and the duration of time over which the rolling average plasma TCT was calculated, for up to 90 days. MOEs were sensitive to factors that modified the toxicological, or hyphenated appropriately no-observed-effects level (NOEL), including rat strain, endpoint used, method of calculating the NOEL, and the pharmacokinetics of elimination, as well as the magnitude of exposure (CWS, calendar year, and use of bias factors). PMID:26794141

PBPK-Based Probabilistic Risk Assessment for Total Chlorotriazines in Drinking Water.

PubMed

Breckenridge, Charles B; Campbell, Jerry L; Clewell, Harvey J; Andersen, Melvin E; Valdez-Flores, Ciriaco; Sielken, Robert L

2016-04-01

The risk of human exposure to total chlorotriazines (TCT) in drinking water was evaluated using a physiologically based pharmacokinetic (PBPK) model. Daily TCT (atrazine, deethylatrazine, deisopropylatrazine, and diaminochlorotriazine) chemographs were constructed for 17 frequently monitored community water systems (CWSs) using linear interpolation and Krieg estimates between observed TCT values. Synthetic chemographs were created using a conservative bias factor of 3 to generate intervening peaks between measured values. Drinking water consumption records from 24-h diaries were used to calculate daily exposure. Plasma TCT concentrations were updated every 30 minutes using the PBPK model output for each simulated calendar year from 2006 to 2010. Margins of exposure (MOEs) were calculated (MOE = [Human Plasma TCTPOD] ÷ [Human Plasma TCTEXP]) based on the toxicological point of departure (POD) and the drinking water-derived exposure to TCT. MOEs were determined based on 1, 2, 3, 4, 7, 14, 28, or 90 days of rolling average exposures and plasma TCT Cmax, or the area under the curve (AUC). Distributions of MOE were determined and the 99.9th percentile was used for risk assessment. MOEs for all 17 CWSs were >1000 at the 99.9(th)percentile. The 99.9(th)percentile of the MOE distribution was 2.8-fold less when the 3-fold synthetic chemograph bias factor was used. MOEs were insensitive to interpolation method, the consumer's age, the water consumption database used and the duration of time over which the rolling average plasma TCT was calculated, for up to 90 days. MOEs were sensitive to factors that modified the toxicological, or hyphenated appropriately no-observed-effects level (NOEL), including rat strain, endpoint used, method of calculating the NOEL, and the pharmacokinetics of elimination, as well as the magnitude of exposure (CWS, calendar year, and use of bias factors). © The Author 2016. Published by Oxford University Press on behalf of the Society of Toxicology.

Use of prostate-specific antigen (PSA) to measure semen exposure resulting from male condom failures: implications for contraceptive efficacy and the prevention of sexually transmitted disease.

PubMed

Walsh, Terri L; Frezieres, Ron G; Peacock, Karen; Nelson, Anita L; Clark, Virginia A; Bernstein, Leslie; Wraxall, Brian G D

2003-02-01

Accurate measurement of semen exposure resulting from condom failures can refine public health messages and improve predictions of condom efficacy in preventing pregnancy and HIV transmission. Eight hundred and thirty couples enrolled in a condom efficacy study were asked to collect a baseline sample of ejaculate from the inside of the first study condom they used and to collect a postcoital vaginal sample whenever a study condom broke or slipped off during intercourse. All samples were quantitatively tested for prostate-specific antigen (PSA), a substance found only in human semen, using rocket immunoelectrophoresis, and inspected microscopically for presence of sperm. Sixty-eight baseline ejaculate samples collected from the inside of the first study condom by couples who subsequently experienced a condom failure averaged 13.4 microg PSA per swab and 79% of the samples averaged one or more sperm per high power field (hpf). Seventy-nine postcoital vaginal samples obtained after a condom break averaged 5.7 microg PSA per swab and only 38% averaged one or more sperm per hpf. The PSA results indicated a 50% reduction in semen exposure compared to baseline levels (p = 0.0001). Seventeen samples obtained after a condom slip-off averaged 2.5 microg PSA per swab and none of the samples averaged one or more sperm per hpf. The PSA results indicated an 80% reduction in semen exposure compared to baseline levels (p = 0.0001). Our results suggest that even condoms that fail reduce the risk of pregnancy and the transmission of sexually transmitted disease compared to unprotected intercourse. We also used PSA results to adjust a model designed to predict consistent-use pregnancy rates from condom breakage and slippage data.

Detailed exposure assessment of dietary furan for infants consuming commercially jarred complementary food based on data from the DONALD study.

PubMed

Lachenmeier, Dirk W; Maser, Elena; Kuballa, Thomas; Reusch, Helmut; Kersting, Mathilde; Alexy, Ute

2012-07-01

Furan is a possible human carcinogen regularly occurring in commercially jarred complementary foods. This paper will provide a detailed exposure assessment for babies consuming these foods considering different intake scenarios. The occurrence data on furan in complementary foods were based on our own headspace-gas chromatography/mass spectrometry (HS-GC/MS) analytical results (n = 286). The average furan content in meals and menus was between 20 and 30 µg kg(-1), which is in excellent agreement with results from other European countries. Using measured food consumption data from the Dortmund Nutritional and Anthropometric Longitudinally Designed (DONALD) study, the average exposures for consumers of commercially jarred foods ranged between 182 and 688 ng kg(-1) bw day(-1), with a worst case scenario for P95 consumers ranging between 351 and 1066 ng kg(-1) bw day(-1). The exposure data were then used to characterize risk using the margin of exposure method based on a benchmark dose lower confidence limit for a 10% response (BMDL10) of 1.28 mg kg(-1) bw day(-1) for hepatocellular tumours in rats. The margin of exposures (MOEs) were below the threshold of 10 000, which is often used to define public health risks, in all scenarios, ranging between 7022 and 1861 for average consumers and between 3642 and 1200 for the P95 consumers. Mitigative measures to avoid furan in complementary foods should be of high priority for risk management. © 2010 Blackwell Publishing Ltd.

Dietary exposure to chloropropanols of secondary school students in Hong Kong.

PubMed

Yau, J C W; Kwong, K P; Chung, S W C; Ho, Y Y; Xiao, Y

2008-01-01

This paper reports levels of 3-monochloropropan-1,2-diol (3-MCPD) and 1,3-dichloro-2-propanol (1,3-DCP) in a wide range of food items and estimates their dietary exposure for secondary school students in Hong Kong. Dietary exposure to chloropropanols was estimated using local food consumption data obtained from secondary school students in 2000 and the concentrations of 3-MCPD and 1,3-DCP in food samples taken from the local market. The dietary exposure to 3-MCPD for an average secondary school student consumer was estimated to be 0.063-0.150 µg kg(-1) body weight (bw) day(-1), whilst that for the high consumer was 0.152-0.300 µg kg(-1) bw day(-1). Both estimates fell below the provisional maximum tolerable daily intake of 2 µg kg(-1) bw established by the Joint Expert Committee on Food Additives (JECFA) and amounted to less than 20% of this safety reference value. The dietary exposure to 1,3-DCP for an average secondary school student consumer was estimated to be 0.003-0.019 µg kg(-1) bw day(-1), whilst that for the high consumer was 0.009-0.040 µg kg(-1) bw day(-1). The resulting margins of exposures were of low concern for human health. It could be concluded that both the average and high secondary school student consumers were unlikely to experience major toxicological effects of 3-MCPD and 1,3-DCP.

Spatial distribution, bioavailability, and health risk assessment of soil Hg in Wuhu urban area, China.

PubMed

Fang, Fengman; Wang, Haidong; Lin, Yuesheng

2011-08-01

Total mercury (Hg(T)) and bioavailability Hg (Hg(HCl)) concentrations in soil were determined in five districts in Wuhu urban area. Spatial pattern of soil Hg concentration was generated through kriging technology. Results showed that Hg concentration in soil ranged from 0.024 to 2.844 mg kg( -1) with an average of 0.207 mg kg( -1). Hg concentration in soil appeared to have a block distribution and decreased from downtown to surrounding district. And Hg concentrations appeared to have a medium scale spatial auto correlation, strongly affected by human activity. The maximal Hg average concentration (0.332 mg kg( -1)) in soil appeared in Jinghu district, where the high intensity of human activities is. Second highest Hg average concentration (0.263 mg kg( -1)) in soil appeared in development district, where the intensive industrial activities are. Bioavailability Hg concentration in soil ranged from 2.6 to 4.9 μg kg( -1) with an average of 3.8 μg kg( -1), which had a ratio of 0.28~6.44% to total Hg. The ratios of bioavailability Hg to total Hg in vegetable soil were bigger than those of park soil. Correlation analysis showed that total Hg, organic matter, total phosphorus, and bioavailability Hg concentrations in soil were significantly positively correlated. Hg concentration in vegetable ranged from 2.7 to 15.2 μg kg( -1) with an average of 6.5 μg kg( -1). Hg concentration in vegetable was positively correlated with Hg(HCl) concentration in soil. According to the calculation on hazard quotient (HQ) for children, inhalation of Hg vapor from soil is the main exposure pathway, in which HQ is 2.517 × 10( -2), accounting for 80.3% of the four exposure pathways. Hazard index (HI) of the four exposure pathways is lower than the "safe" level of HI = 1; therefore, exposure of soil Hg exhibited little potential health risk to children in Wuhu urban area.

Multi-sector thermo-physiological head simulator for headgear research

NASA Astrophysics Data System (ADS)

Martinez, Natividad; Psikuta, Agnes; Corberán, José Miguel; Rossi, René M.; Annaheim, Simon

2017-02-01

A novel thermo-physiological human head simulator for headgear testing was developed by coupling a thermal head manikin with a thermo-physiological model. As the heat flux at head-site is directly measured by the head manikin, this method provides a realistic quantification of the heat transfer phenomena occurring in the headgear, such as moisture absorption-desorption cycles, condensation, or moisture migration across clothing layers. Before coupling, the opportunities of the head manikin for representing the human physiology were evaluated separately. The evaluation revealed reduced precision in forehead and face temperature predictions under extreme heterogeneous temperature distributions and no initial limitation for simulating temperature changes observed in the human physiology. The thermo-physiological model predicted higher sweat rates when applied for coupled than for pure virtual simulations. After coupling, the thermo-physiological human head simulator was validated using eight human experiments. It precisely predicted core, mean skin, and forehead temperatures with average rmsd values within the average experimental standard deviation (rmsd of 0.20 ± 0.15, 0.83 ± 0.34, and 1.04 ± 0.54 °C, respectively). However, in case of forehead, precision was lower for the exposures including activity than for the sedentary exposures. The representation of the human sweat evaporation could be affected by a reduced evaporation efficiency and the manikin sweat dynamics. The industry will benefit from this thermo-physiological human head simulator leading to the development of helmet designs with enhanced thermal comfort and, therefore, with higher acceptance by users.

Fatty acid ethyl esters (FAEE); comparative accumulation in human and guinea pig hair as a biomarker for prenatal alcohol exposure.

PubMed

Kulaga, Vivian; Caprara, Daniela; Iqbal, Umar; Kapur, Bhushan; Klein, Julia; Reynolds, James; Brien, James; Koren, Gideon

2006-01-01

To compare the incorporation rate (ICR) of fatty acid ethyl esters (FAEE) in hair between guinea pigs and humans, and to assess the relationship between ethanol exposure and FAEE concentrations in hair. Published data from pregnant guinea pigs, including maximum blood ethanol concentration (BEC), dosage regimen, and total hair FAEE concentration, were compared with published data from alcoholic patients, where dose of ethanol consumed and total hair FAEE concentration were reported. Mean values of ethanol Vmax for pregnant guinea pigs and humans were obtained from published data (26.2 and 24 mg/dl/h, respectively). Total and individual FAEE ICRs, defined as the ratio of hair FAEE to the area under the BEC-time curve (total systemic ethanol exposure), were found to be on average an order of magnitude lower in the guinea pig than in the human. The profiles of ester incorporation also differed slightly between species, with ethyl stearate being highly incorporated in guinea pig hair and less so in human hair. The results may reflect in the human greater FAEE production, greater FAEE deposition in hair, slower FAEE catabolism, differential sebum production and composition, or a combination thereof. Also, ethyl oleate was found to correlate with total systemic ethanol exposure for both guinea pigs and humans, correlation coefficients equalling 0.67 (P < 0.05) and 0.49 (P < 0.05), respectively. No other ethyl esters, nor total FAEE, were found to correlate with systemic ethanol exposure. When extrapolating FAEE concentrations in hair from guinea pigs to humans, an order of magnitude difference should be considered, with humans incorporating more FAEE per unit of ethanol exposure. Also, the results suggest caution should be taken when interpreting values of single esters because of their differential incorporation among species. Lastly, our findings suggest ethyl oleate may be of keen interest in FAEE hair analysis, particularly across species.

Cognitive effects of radiation emitted by cellular phones: the influence of exposure side and time.

PubMed

Luria, Roy; Eliyahu, Ilan; Hareuveny, Ronen; Margaliot, Menachem; Meiran, Nachshon

2009-04-01

This study examined the time dependence effects of exposure to radiofrequency radiation (RFR) emitted by standard GSM cellular phones on the cognitive functions of humans. A total of 48 healthy right-handed male subjects performed a spatial working memory task (that required either a left-hand or a right-hand response) while being exposed to one of two GSM phones placed at both sides of the head. The subjects were randomly divided into three groups. Each group was exposed to one of three exposure conditions: left-side of the head, right-side, or sham-exposure. The experiment consisted of 12 blocks of trials. Response times (RTs) and accuracy of the responses were recorded. It was found that the average RT of the right-hand responses under left-side exposure condition was significantly longer than those of the right-side and sham-exposure groups averaged together during the first two time blocks. These results confirmed the existence of an effect of exposure on RT, as well as the fact that exposure duration (together with the responding hand and the side of exposure) may play an important role in producing detectable RFR effects on performance. Differences in these parameters might be the reason for the failure of certain studies to detect or replicate RFR effects. (c) 2008 Wiley-Liss, Inc.

Assessing human exposure to power-frequency electric and magnetic fields.

PubMed Central

Kaune, W T

1993-01-01

This paper reviews published literature and current problems relating to the assessment of occupational and residential human exposures to power-frequency electric and magnetic fields. Available occupational exposure data suggest that the class of job titles known as electrical workers may be an effective surrogate for time-weighted-average (TWA) magnetic-field (but not electric-field) exposure. Current research in occupational-exposure assessment is directed to the construction of job-exposure matrices based on electric- and magnetic-field measurements and estimates of worker exposures to chemicals and other factors of interest. Recent work has identified five principal sources of residential magnetic fields: electric power transmission lines, electric power distribution lines, ground currents, home wiring, and home appliances. Existing residential-exposure assessments have used one or more of the following techniques: questionnaires, wiring configuration coding, theoretical field calculations, spot electric- and magnetic-field measurements, fixed-site magnetic-field recordings, personal- exposure measurements, and geomagnetic-field measurements. Available normal-power magnetic-field data for residences differ substantially between studies. It is not known if these differences are due to geographical differences, differences in measurement protocols, or instrumentation differences. Wiring codes and measured magnetic fields (but not electric fields) are associated weakly. Available data suggest, but are far from proving, that spot measurements may be more effective than wire codes as predictors of long-term historical magnetic-field exposure. Two studies find that away-from-home TWA magnetic-field exposures are less variable than at-home exposures. The importance of home appliances as contributors to total residential magnetic-field exposure is not known at this time. It also is not known what characteristics (if any) of residential electric and magnetic fields are determinants of human health effects. PMID:8206021

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

PubMed

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

2016-11-01

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

Ultrafine particles in cities.

PubMed

Kumar, Prashant; Morawska, Lidia; Birmili, Wolfram; Paasonen, Pauli; Hu, Min; Kulmala, Markku; Harrison, Roy M; Norford, Leslie; Britter, Rex

2014-05-01

Ultrafine particles (UFPs; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. Globally, the major source for urban outdoor UFP concentrations is motor traffic. Ongoing trends towards urbanisation and expansion of road traffic are anticipated to further increase population exposure to UFPs. Numerous experimental studies have characterised UFPs in individual cities, but an integrated evaluation of emissions and population exposure is still lacking. Our analysis suggests that the average exposure to outdoor UFPs in Asian cities is about four-times larger than that in European cities but impacts on human health are largely unknown. This article reviews some fundamental drivers of UFP emissions and dispersion, and highlights unresolved challenges, as well as recommendations to ensure sustainable urban development whilst minimising any possible adverse health impacts. Copyright © 2014 Elsevier Ltd. All rights reserved.

Concentration and Risk Evaluation of Polycyclic Aromatic Hydrocarbons in Urban Soil in the Typical Semi-Arid City of Xi’an in Northwest China

PubMed Central

Wang, Lijun; Zhang, Shengwei; Wang, Li; Zhang, Wenjuan; Shi, Xingmin; Lu, Xinwei; Li, Xiaoping; Li, Xiaoyun

2018-01-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants, presenting potential threats to the ecological environment and human health. Sixty-two urban soil samples were collected in the typical semi-arid city of Xi’an in Northwest China. They were analyzed for concentration, pollution, and ecological and health risk of sixteen U.S. Environmental Protection Agency priority PAHs. The total concentrations of the sixteen PAHs (Σ16PAHs) in the urban soil ranged from 390.6 to 10,652.8 µg/kg with an average of 2052.6 µg/kg. The concentrations of some individual PAHs in the urban soil exceeded Dutch Target Values of Soil Quality and the Σ16PAHs represented heavy pollution. Pyrene and dibenz[a,h]anthracene had high ecological risk to aquatic/soil organisms, while other individual PAHs showed low ecological risk. The total ecological risk of PAHs to aquatic/soil organisms is classified as moderate. Toxic equivalency quantities (TEQs) of the sixteen PAHs varied between 21.16 and 1625.78 µg/kg, with an average of 423.86 µg/kg, indicating a relatively high toxicity potential. Ingestion and dermal adsorption of soil dust were major pathways of human exposure to PAHs from urban soil. Incremental lifetime cancer risks (ILCRs) of human exposure to PAHs were 2.86 × 10−5 for children and 2.53 × 10−5 for adults, suggesting that the cancer risk of human exposure to PAHs from urban soil is acceptable. PMID:29584654

Occupational Exposure of Diesel Station Workers to BTEX Compounds at a Bus Depot

PubMed Central

Moolla, Raeesa; Curtis, Christopher J.; Knight, Jasper

2015-01-01

Diesel fuel is known to emit pollutants that have a negative impact on environmental and human health. In developing countries like South Africa, attendants are employed to pump fuel for customers at service stations. Attendants refuel vehicles with various octane unleaded fuel, lead-replacement petrol and diesel fuel, on a daily basis. Attendants are at risk to adverse health effects associated with the inhalation of volatile organic compounds released from these fuels. The pollutants released include benzene, toluene, ethylbenzene and xylenes (BTEX), which are significant due to their high level of toxicity. In this study, a risk assessment of BTEX was conducted at a diesel service station for public buses. Using Radiello passive samplers, it was found that benzene concentrations were above recommended international standards. Due to poor ventilation and high exposure duration, the average benzene concentration over the sampling campaign exceeded the US Environmental Protection Agency’s chronic inhalation exposure reference concentration. Lifetime cancer risk estimation showed that on average there is a 3.78 × 10−4 cancer risk, corresponding to an average chronic daily intake of 1.38 × 10−3 mg/kg/day of benzene exposure. Additionally, there were incidences where individuals were at potential hazard risk of benzene and toluene that may pose non-carcinogenic effects to employees. PMID:25872020

Occupational exposure of diesel station workers to BTEX compounds at a bus depot.

PubMed

Moolla, Raeesa; Curtis, Christopher J; Knight, Jasper

2015-04-13

Diesel fuel is known to emit pollutants that have a negative impact on environmental and human health. In developing countries like South Africa, attendants are employed to pump fuel for customers at service stations. Attendants refuel vehicles with various octane unleaded fuel, lead-replacement petrol and diesel fuel, on a daily basis. Attendants are at risk to adverse health effects associated with the inhalation of volatile organic compounds released from these fuels. The pollutants released include benzene, toluene, ethylbenzene and xylenes (BTEX), which are significant due to their high level of toxicity. In this study, a risk assessment of BTEX was conducted at a diesel service station for public buses. Using Radiello passive samplers, it was found that benzene concentrations were above recommended international standards. Due to poor ventilation and high exposure duration, the average benzene concentration over the sampling campaign exceeded the US Environmental Protection Agency's chronic inhalation exposure reference concentration. Lifetime cancer risk estimation showed that on average there is a 3.78 × 10-4 cancer risk, corresponding to an average chronic daily intake of 1.38 × 10-3 mg/kg/day of benzene exposure. Additionally, there were incidences where individuals were at potential hazard risk of benzene and toluene that may pose non-carcinogenic effects to employees.

Time Scale Effects in Acute Association between Air-Pollution and Mortality

EPA Science Inventory

We used wavelet analysis and generalized additive models (GAM) to study timescale effects in the acute association between mortality and air-pollution. Daily averages of measured NO₂ concentrations in the metropolitan Paris area are used as indicators of human exposure...

Numerical compliance testing of human exposure to electromagnetic radiation from smart-watches.

PubMed

Hong, Seon-Eui; Lee, Ae-Kyoung; Kwon, Jong-Hwa; Pack, Jeong-Ki

2016-10-07

In this study, we investigated the electromagnetic dosimetry for smart-watches. At present, the standard for compliance testing of body-mounted and handheld devices specifies the use of a flat phantom to provide conservative estimates of the peak spatial-averaged specific absorption rate (SAR). This means that the estimated SAR using a flat phantom should be higher than the SAR in the exposure part of an anatomical human-body model. To verify this, we numerically calculated the SAR for a flat phantom and compared it with the numerical calculation of the SAR for four anatomical human-body models of different ages. The numerical analysis was performed using the finite difference time domain method (FDTD). The smart-watch models were used in the three antennas: the shorted planar inverted-F antenna (PIFA), loop antenna, and monopole antenna. Numerical smart-watch models were implemented for cellular commutation and wireless local-area network operation at 835, 1850, and 2450 MHz. The peak spatial-averaged SARs of the smart-watch models are calculated for the flat phantom and anatomical human-body model for the wrist-worn and next to mouth positions. The results show that the flat phantom does not provide a consistent conservative SAR estimate. We concluded that the difference in the SAR results between an anatomical human-body model and a flat phantom can be attributed to the different phantom shapes and tissue structures.

Numerical compliance testing of human exposure to electromagnetic radiation from smart-watches

NASA Astrophysics Data System (ADS)

Hong, Seon-Eui; Lee, Ae-Kyoung; Kwon, Jong-Hwa; Pack, Jeong-Ki

2016-10-01

In this study, we investigated the electromagnetic dosimetry for smart-watches. At present, the standard for compliance testing of body-mounted and handheld devices specifies the use of a flat phantom to provide conservative estimates of the peak spatial-averaged specific absorption rate (SAR). This means that the estimated SAR using a flat phantom should be higher than the SAR in the exposure part of an anatomical human-body model. To verify this, we numerically calculated the SAR for a flat phantom and compared it with the numerical calculation of the SAR for four anatomical human-body models of different ages. The numerical analysis was performed using the finite difference time domain method (FDTD). The smart-watch models were used in the three antennas: the shorted planar inverted-F antenna (PIFA), loop antenna, and monopole antenna. Numerical smart-watch models were implemented for cellular commutation and wireless local-area network operation at 835, 1850, and 2450 MHz. The peak spatial-averaged SARs of the smart-watch models are calculated for the flat phantom and anatomical human-body model for the wrist-worn and next to mouth positions. The results show that the flat phantom does not provide a consistent conservative SAR estimate. We concluded that the difference in the SAR results between an anatomical human-body model and a flat phantom can be attributed to the different phantom shapes and tissue structures.

Evaluation of cosmetic product exposures reported to the Milan Poison Control Centre, Italy from 2005 to 2010.

PubMed

Ruggiero, Simona; Moro, Paola Angela; Davanzo, Franca; Capuano, Annalisa; Rossi, Francesco; Sautebin, Lidia

2012-12-01

To the average consumer, "cosmetics" are not considered to cause damage to human health under normal conditions of use. Thus, cosmetic "safety" does not require any particular attention to the possibility that cosmetics may result in a toxic exposure, especially for children. Poison Control Centres (PCCs) provide specialized and rapid information for consumers and health professionals to ensure management of events related to the exposures to different agents, including Cosmetics. Poison Control Centres also represent a unique source of information to investigate the frequency and type of exposures to cosmetic and the related risks. An analysis of cases concerning human exposures to cosmetics collected from 2005 to 2010 by the PCC at the Ospedale Niguarda Ca' Granda (Milan, Italy) was performed. During this period, 11 322 human exposure cases related to cosmetics were collected accounting for 4.5% of the total human clinical cases. Almost, all the requests for assistance came from consumers (53%) and hospitals (40%). The most frequently reported site of exposure was the consumer's own residence (94%). The exposures mainly involved children younger than 4 years (77%). No difference in gender distribution was observed (female 49%, male 51%). Almost, all of the exposures were unintentional (94%). Intentional exposures, mainly related to suicide attempts and accounted for 6% of cases involving persons aged more than 12 years. Personal hygiene products (30%), perfumes and hair care products (excluding hair dyes) (both 13%) were the most frequently involved categories. Symptoms were present only in 26% of the exposures and were mostly gastrointestinal (46%). Most of the cases were managed at home (43%) whereas hospital intervention was required in 38%. Since the exposure frequency seems more likely to reflect product availability and accessibility to ingestors, our results call for closer attention to this type of hazard, especially for children younger than 4 years of age.

Long-term impacts of unconventional drilling operations on human and animal health.

PubMed

Bamberger, Michelle; Oswald, Robert E

2015-01-01

Public health concerns related to the expansion of unconventional oil and gas drilling have sparked intense debate. In 2012, we published case reports of animals and humans affected by nearby drilling operations. Because of the potential for long-term effects of even low doses of environmental toxicants and the cumulative impact of exposures of multiple chemicals by multiple routes of exposure, a longitudinal study of these cases is necessary. Twenty-one cases from five states were followed longitudinally; the follow-up period averaged 25 months. In addition to humans, cases involved food animals, companion animals and wildlife. More than half of all exposures were related to drilling and hydraulic fracturing operations; these decreased slightly over time. More than a third of all exposures were associated with wastewater, processing and production operations; these exposures increased slightly over time. Health impacts decreased for families and animals moving from intensively drilled areas or remaining in areas where drilling activity decreased. In cases of families remaining in the same area and for which drilling activity either remained the same or increased, no change in health impacts was observed. Over the course of the study, the distribution of symptoms was unchanged for humans and companion animals, but in food animals, reproductive problems decreased and both respiratory and growth problems increased. This longitudinal case study illustrates the importance of obtaining detailed epidemiological data on the long-term health effects of multiple chemical exposures and multiple routes of exposure that are characteristic of the environmental impacts of unconventional drilling operations.

Computational fluid dynamics modeling of Bacillus anthracis spore deposition in rabbit and human respiratory airways

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

Kabilan, S.; Suffield, S. R.; Recknagle, K. P.

Three-dimensional computational fluid dynamics and Lagrangian particle deposition models were developed to compare the deposition of aerosolized Bacillus anthracis spores in the respiratory airways of a human with that of the rabbit, a species commonly used in the study of anthrax disease. The respiratory airway geometries for each species were derived respectively from computed tomography (CT) and µCT images. Both models encompassed airways that extended from the external nose to the lung with a total of 272 outlets in the human model and 2878 outlets in the rabbit model. All simulations of spore deposition were conducted under transient, inhalation–exhalation breathingmore » conditions using average species-specific minute volumes. Two different exposure scenarios were modeled in the rabbit based upon experimental inhalation studies. For comparison, human simulations were conducted at the highest exposure concentration used during the rabbit experimental exposures. Results demonstrated that regional spore deposition patterns were sensitive to airway geometry and ventilation profiles. Due to the complex airway geometries in the rabbit nose, higher spore deposition efficiency was predicted in the nasal sinus compared to the human at the same air concentration of anthrax spores. In contrast, higher spore deposition was predicted in the lower conducting airways of the human compared to the rabbit lung due to differences in airway branching pattern. This information can be used to refine published and ongoing biokinetic models of inhalation anthrax spore exposures, which currently estimate deposited spore concentrations based solely upon exposure concentrations and inhaled doses that do not factor in species-specific anatomy and physiology for deposition.« less

DNA methylation levels and long-term trihalomethane exposure in drinking water: an epigenome-wide association study

PubMed Central

Salas, Lucas A; Bustamante, Mariona; Gonzalez, Juan R; Gracia-Lavedan, Esther; Moreno, Victor; Kogevinas, Manolis; Villanueva, Cristina M

2015-01-01

Trihalomethanes (THM) are undesired disinfection byproducts (DBPs) formed during water treatment. Mice exposed to DBPs showed global DNA hypomethylation and c-myc and c-jun gene-specific hypomethylation, while evidence of epigenetic effects in humans is scarce. We explored the association between lifetime THM exposure and DNA methylation through an epigenome-wide association study. We selected 138 population-based controls from a case-control study of colorectal cancer conducted in Barcelona, Spain, exposed to average lifetime THM levels ≤85 μg/L vs. >85 μg/L (N = 68 and N = 70, respectively). Mean age of participants was 70 years, and 54% were male. Average lifetime THM level in the exposure groups was 64 and 130 µg/L, respectively. DNA was extracted from whole blood and was bisulphite converted to measure DNA methylation levels using the Illumina HumanMethylation450 BeadChip. Data preprocessing was performed using RnBeads. Methylation was compared between exposure groups using empirical Bayes moderated linear regression for CpG sites and Gaussian kernel for CpG regions. ConsensusPathDB was used for gene set enrichment. Statistically significant differences in methylation between exposure groups was found in 140 CpG sites and 30 gene-related regions, after false discovery rate <0.05 and adjustment for age, sex, methylation first principal component, and blood cell proportion. The annotated genes were localized to several cancer pathways. Among them, 29 CpGs had methylation levels associated with THM levels (|Δβ|≥0.05) located in 11 genes associated with cancer in other studies. Our results suggest that THM exposure may affect DNA methylation in genes related to tumors, including colorectal and bladder cancers. Future confirmation studies are required. PMID:26039576

Time-averaged exposures to 220Rn and 222Rn progeny in Colorado homes.

PubMed

Martz, D E; Falco, R J; Langner, G H

1990-06-01

Week-long time-averaged exposures to naturally occurring 220Rn and 222Rn progeny have been measured at several locations in Colorado by monitoring the alpha activity collected continuously on a fixed-membrane filter. The alpha-energy spectrum associated with the activity collected on the filter was recorded every 15 min using a microcomputer-controlled alpha spectrometer. The alpha counts observed in three energy regions permitted complete separation of the contributions from each decay chain, and calculation of the separate time-averaged potential alpha-energy concentrations in air from 220Rn progeny, PAEC(Tn), and from 222Rn progeny, PAEC(Rn). The time-averaged PAEC(Tn) ranged from 0.3 to 6.9 mWL at 12 indoor locations, and the time-averaged PAEC(Rn) ranged from 1.0 to 59.0 mWL. The ratios of the indoor PAEC(Tn) to indoor PAEC(Rn) ranged from 0.09 to 0.58, with an overall average ratio of 0.32 and a standard deviation of 0.15. The 10 L min-1 flow rate through the filter was selected to approximate the air intake rate of a resting human; the time-averaged PAEC thus represents the progeny concentrations that would have been inhaled by a person breathing the same atmosphere.

Environmental impact and site-specific human health risks of chromium in the vicinity of a ferro-alloy manufactory, China.

PubMed

Wang, Zhen-xing; Chen, Jian-qun; Chai, Li-yuan; Yang, Zhi-hui; Huang, Shun-hong; Zheng, Yu

2011-06-15

Previous studies often neglected the direct exposure to soil heavy metals in human health risk assessment. The purpose of this study was to assess the environmental impact and site-specific health risks of chromium (Cr) by both direct and indirect exposure assessment method. Results suggested that total Cr was shown a substantial buildup with a significant increase in the industrial and cultivated soils (averaged 1910 and 986 mg kg(-1), respectively). The Cr contents of vegetables exceeded the maximum permissible concentration by more than four times in every case. Human exposure to Cr was mainly due to dietary food intake in farming locations and due to soil ingestion in both industrial and residential sites. Soil ingestion was the main contributor pathway for direct exposure, followed by inhalation, and then dermal contact. The highest risks of vegetable ingestion were associated with consumption of Chinese cabbage. The results also indicated that plant tissues are able to convert the potentially toxic Cr (VI) species into the non-toxic Cr (III) species. The analyses of human health risks indicated that an important portion of the population is at risk, especially in the industrial site. Copyright © 2011 Elsevier B.V. All rights reserved.

Improving the risk assessment of lipophilic persistent environmental chemicals in breast milk

EPA Science Inventory

BACKGROUND: A breastfeeding infant’s intake of persistent organic pollutants (POPs) may be much greater than his/her mother’s average daily POP exposure. In many cases, current human health risk assessment methods do not account for differences between maternal and infant POP exp...

Radiation exposures due to fossil fuel combustion

NASA Astrophysics Data System (ADS)

Beck, Harold L.

The current consensus regarding the potential radiation exposures resulting from the combustion of fossil fuels is examined. Sources, releases and potential doses to humans are discussed, both for power plants and waste materials. It is concluded that the radiation exposure to most individuals from any pathway is probably insignificant, i.e. only a tiny fraction of the dose received from natural sources in soil and building materials. Any small dose that may result from power-plant emissions will most likely be from inhalation of the small insoluble ash particles from the more poorly controlled plants burning higher than average activity fuel, rather than from direct or indirect ingestion of food grown on contaminated soil. One potentially significant pathway for exposure to humans that requires further evaluation is the effect on indoor external γ-radiation levels resulting from the use of flyash in building materials. The combustion of natural gas in private dwellings is also discussed, and the radiological consequences are concluded to be generally insignificant, except under certain extraordinary circumstances.

Human health risk analysis from disinfection by-products (DBPs) in drinking and bathing water of some Indian cities

PubMed Central

2014-01-01

Background Human health risk assessment from exposure to disinfection by-products (DBPs) during drinking and bathing water vary from country to country as per life expectancy, body mass index, water consumption pattern and individual concentration of DBPs component, etc. Methods Present study considered average direct water intake per person for adult males and females as 4 & 3 L/day, respectively as per Indian literature for risk evaluation from another component of pollutant. While other important factor like average life expectancy, body weight & body surface area for male and female were considered 64 & 67 years, 51.9 & 45.4 Kg and 1.54 & 1.38 m2 respectively as per Indian Council of Medical Research and WHO report. The corresponding lifetime cancer risk of the formed THMs to human beings was estimated by the USEPA and IRIS method as per Indian population. Results The total cancer risk reached 8.99 E-04 and 8.92 E-04 for males and females, respectively, the highest risk from THMs seems to be from the inhalation route followed by ingestion and dermal contacts. Conclusions The multipath way evaluations of lifetime cancer risks for THMs exposure through ingestion, dermal absorption, and inhalation exposure were examined at the highest degree of danger. Results reveals that water containing THMs of the selected water treatment plant of the eastern part of India was unsafe in terms of risk evaluation through inhalation and ingestion, while dermal route of risk was found very close to permissible limit of USEPA. Sensitivity analysis shows that every input parameter is sole responsible for total risk potential, whereas exposure duration playing important role for estimation of total risk. PMID:24872885

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

PubMed

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 © 2016 Elsevier B.V. All rights reserved.

Glazed clay pottery and lead exposure in Mexico: Current experimental evidence.

PubMed

Diaz-Ruiz, Araceli; Tristán-López, Luis Antonio; Medrano-Gómez, Karen Itzel; Torres-Domínguez, Juan Alejandro; Ríos, Camilo; Montes, Sergio

2017-11-01

Lead exposure remains a significant environmental problem; lead is neurotoxic, especially in developing humans. In Mexico, lead in human blood is still a concern. Historically, much of the lead exposure is attributed to the use of handcrafted clay pottery for cooking, storing and serving food. However, experimental cause-and-effect demonstration is lacking. The present study explores this issue with a prospective experimental approach. We used handcrafted clay containers to prepare and store lemonade, which was supplied as drinking water to pregnant rats throughout the gestational period. We found that clay pots, jars, and mugs leached on average 200 µg/l lead, and exposure to the lemonade resulted in 2.5 µg/dl of lead in the pregnant rats' blood. Neonates also showed increased lead content in the hippocampus and cerebellum. Caspase-3 activity was found to be statistically increased in the hippocampus in prenatally exposed neonates, suggesting increased apoptosis in that brain region. Glazed ceramics are still an important source of lead exposure in Mexico, and our results confirm that pregnancy is a vulnerable period for brain development.

Probabilistic risk assessment of exposure to leucomalachite green residues from fish products.

PubMed

Chu, Yung-Lin; Chimeddulam, Dalaijamts; Sheen, Lee-Yan; Wu, Kuen-Yuh

2013-12-01

To assess the potential risk of human exposure to carcinogenic leucomalachite green (LMG) due to fish consumption, the probabilistic risk assessment was conducted for adolescent, adult and senior adult consumers in Taiwan. The residues of LMG with the mean concentration of 13.378±20.56 μg kg(-1) (BFDA, 2009) in fish was converted into dose, considering fish intake reported for three consumer groups by NAHSIT (1993-1996) and body weight of an average individual of the group. The lifetime average and high 95th percentile dietary intakes of LMG from fish consumption for Taiwanese consumers were estimated at up to 0.0135 and 0.0451 μg kg-bw(-1) day(-1), respectively. Human equivalent dose (HED) of 2.875 mg kg-bw(-1) day(-1) obtained from a lower-bound benchmark dose (BMDL10) in mice by interspecies extrapolation was linearly extrapolated to oral cancer slope factor (CSF) of 0.035 (mgkg-bw(-1)day(-1))(-1) for humans. Although, the assumptions and methods are different, the results of lifetime cancer risk varying from 3×10(-7) to 1.6×10(-6) were comparable to those of margin of exposures (MOEs) varying from 410,000 to 4,800,000. In conclusions, Taiwanese fish consumers with the 95th percentile LADD of LMG have greater risk of liver cancer and need to an action of risk management in Taiwan. Copyright © 2013 Elsevier Ltd. All rights reserved.

Occurrence of toluene in Canadian total diet foods and its significance to overall human exposure.

PubMed

Cao, Xu-Liang; Pelletier, Luc; Sparling, Melissa; Dabeka, Robert

2018-01-01

Levels of most VOCs in foods are usually low because of their volatility, and human exposure to VOCs is expected to be mainly via inhalation of ambient and indoor air. However, dietary exposures to VOCs can be significant to overall exposures if elevated concentrations of VOCs are present in foods consumed in high amounts and/or on a regular basis, and this was demonstrated in this study with the occurrence data of toluene from the recent 2014 Canadian Total Diet Study (TDS). Concentrations of toluene in the composite samples of most food types from the 2014 TDS are low and similar to the results from the previous 2007 TDS with some exceptions, such as beef steak (670 ng/g (2014 TDS) vs. 14 ng/g (2007 TDS)), poultry, chicken and turkey (307 ng/g (2014 TDS) vs. 8.8 ng/g (2007 TDS)). Toluene concentrations in most of the grain-based and fast food composite samples from the 2014 TDS are considerably higher than those from the 2007 TDS, with the highest level of 4655 ng/g found in the composite sample of crackers from the 2014 TDS (compared to 18 ng/g from 2007 TDS). Dietary exposure estimates for toluene based on the occurrence results from the 2014 TDS show that for most of the age groups, grain-based foods are the primary source, accounting for an average of 77.5% of the overall toluene intake from the diet. The highest dietary exposures to toluene were observed for the adult age groups, with estimated average exposures ranging from 177.4 to 184.5 µg/d. Dietary exposure estimates to toluene are well below oral doses associated with toxicological effects and also below the maximum estimated intake (819 µg/d) from air inhalation for adult group (20 - 70 years) based on the results from CEPA (Canadian Environmental Protection Act) assessment in 1992.

Perfluoroalkyl and polyfluoroalkyl substances and human fetal growth: a systematic review.

PubMed

Bach, Cathrine Carlsen; Bech, Bodil Hammer; Brix, Nis; Nohr, Ellen Aagaard; Bonde, Jens Peter Ellekilde; Henriksen, Tine Brink

2015-01-01

Exposure to perfluoroalkyl and polyfluoroalkyl substances (PFASs) is ubiquitous in most regions of the world. The most commonly studied PFASs are perfluorooctane sulfonate (PFOS) and perfluorooctanoate (PFOA). Animal studies indicate that maternal PFAS exposure is associated with reduced fetal growth. However, the results of human studies are inconsistent. To summarize the evidence of an association between exposure to PFASs, particularly PFOS and PFOA, and human fetal growth. Systematic literature searches were performed in MEDLINE and EMBASE. We included original studies on pregnant women with measurements of PFOA or PFOS in maternal blood during pregnancy or the umbilical cord and associations with birth weight or related outcomes according to the PFAS level. Citations and references from the included articles were investigated to locate more relevant articles. Study characteristics and results were extracted to structured tables. The completeness of reporting as well as the risk of bias and confounding were assessed. Fourteen studies were eligible. In utero PFOA exposure was associated with decreased measures of continuous birth weight in all studies, even though the magnitude of the association differed and many results were statistically insignificant. PFOS exposure and birth weight were associated in some studies, while others found no association. Higher PFOS and PFOA concentrations were associated with decreased average birth weight in most studies, but only some results were statistically significant. The impact on public health is unclear, but the global exposure to PFASs warrants further investigation.

Analysis of PFAAs in American alligators part 2: Potential dietary exposure of South Carolina hunters from recreationally harvested alligator meat.

PubMed

Tipton, Jessica J; Guillette, Louis J; Lovelace, Susan; Parrott, Benjamin B; Rainwater, Thomas R; Reiner, Jessica L

2017-11-01

Exposure to perfluorinated alkyl acids (PFAAs) has been linked to many harmful health effects including reproductive disorders, developmental delays, and altered liver and kidney function. Most human exposure to environmental contaminants, including PFAAs, occurs through consumption of contaminated food or drinking water. This study uses PFAA data from meat samples collected from recreationally harvested American alligators (Alligator mississippiensis) in South Carolina to assess potential dietary exposure of hunters and their families to PFAAs. Consumption patterns were investigated using intercept surveys of 23 hunters at a wild game meat processor. An exposure scenario using the average consumption frequency, portion size, and median perfluorooctane sulfonic acid (PFOS) concentration in alligator meat from all hunt units found the daily dietary exposure to be 2.11ng/kg body weight per day for an adult human. Dietary PFOS exposure scenarios based on location of harvest suggested the highest daily exposure occurs with alligator meat from the Middle Coastal hunt unit in South Carolina. Although no samples were found to exceed the recommended threshold for no consumption of PFOS found in Minnesota state guidelines, exposure to a mixture of PFAAs found in alligator meat and site-specific exposures based on harvest location should be considered in determining an appropriate guideline for vulnerable populations potentially exposed to PFAAs through consumption of wild alligator meat. Copyright © 2017. Published by Elsevier B.V.

Modeling population exposures to outdoor sources of hazardous air pollutants.

PubMed

Ozkaynak, Halûk; Palma, Ted; Touma, Jawad S; Thurman, James

2008-01-01

Accurate assessment of human exposures is an important part of environmental health effects research. However, most air pollution epidemiology studies rely upon imperfect surrogates of personal exposures, such as information based on available central-site outdoor concentration monitoring or modeling data. In this paper, we examine the limitations of using outdoor concentration predictions instead of modeled personal exposures for over 30 gaseous and particulate hazardous air pollutants (HAPs) in the US. The analysis uses the results from an air quality dispersion model (the ASPEN or Assessment System for Population Exposure Nationwide model) and an inhalation exposure model (the HAPEM or Hazardous Air Pollutant Exposure Model, Version 5), applied by the US. Environmental protection Agency during the 1999 National Air Toxic Assessment (NATA) in the US. Our results show that the total predicted chronic exposure concentrations of outdoor HAPs from all sources are lower than the modeled ambient concentrations by about 20% on average for most gaseous HAPs and by about 60% on average for most particulate HAPs (mainly, due to the exclusion of indoor sources from our modeling analysis and lower infiltration of particles indoors). On the other hand, the HAPEM/ASPEN concentration ratio averages for onroad mobile source exposures were found to be greater than 1 (around 1.20) for most mobile-source related HAPs (e.g. 1, 3-butadiene, acetaldehyde, benzene, formaldehyde) reflecting the importance of near-roadway and commuting environments on personal exposures to HAPs. The distribution of the ratios of personal to ambient concentrations was found to be skewed for a number of the VOCs and reactive HAPs associated with major source emissions, indicating the importance of personal mobility factors. We conclude that the increase in personal exposures from the corresponding predicted ambient levels tends to occur near locations where there are either major emission sources of HAPs or when individuals are exposed to either on- or nonroad sources of HAPs during their daily activities. These findings underscore the importance of applying exposure-modeling methods, which incorporate information on time-activity, commuting, and exposure factors data, for the purposes of assigning exposures in air pollution health studies.

Issues of human rabies immunoglobulin and vaccine: policy versus practice.

PubMed

Folb, Jonathan E; Cooke, Richard P D

2007-03-01

A retrospective audit was conducted of all issues of rabies vaccine or human rabies immunoglobulin (HRIG) from the Clinical Microbiology Department at University Hospital Aintree for post-exposure prophylaxis. The appropriateness of management was reviewed by a blinded panel, which used guidelines issued by the Health Protection Agency (HPA) as a standard. Thirty-six enquiries, on average 9 days following exposure, led to issues of HRIG, rabies vaccine or both. Dog bites accounted for the majority of incidents. In no cases was the biting animal recorded as having been observed for signs of rabies. Management was judged to have been inappropriate in 9 cases, and documentation was judged to have been unsatisfactory in 13 cases. This study has highlighted several areas of ambiguity in the current guidelines, and a number of deficiencies in the information prompted by the standardized proformas used to deal with post-exposure queries.

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

PubMed

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

2012-07-01

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

ACUTE CHANGES IN SPUTUM COLLECTED FROM EXPOSED HUMAN SUBJECTS IN MINING CONDITIONS

PubMed Central

Wong, Simon S.; Sun, Nina N.; Miller, Hugh B.; Witten, Mark L.; Burgess, Jefferey L.

2015-01-01

Neprilysin (NEP) is a key cell surface peptidase in the maintenance of airway homeostasis and the development of pulmonary disorders. However, little information is available about the effect of particulate matter (PM) on airway NEP. In this controlled human exposure study, changes in induced sputum were measured in eleven subjects at baseline, overshot (OS) mucking, and diesel exhaust (DE) exposure days. Neither OS condition nor DE exposure was found to induce significant changes in total protein, but DE induced significant increases in cell numbers of macrophages and epithelium. Moreover, significant increases in soluble NEP were observed following OS mining dust particulates (0.43 ± 0.06, p = 0.023) and DE exposure (0.30 ± 0.04, p = 0.035) when compared with the baseline control (0.40 ± 0.03), with 42% and 31% average net increase, respectively. Pearson’s correlation analyses indicated that sputum NEP activity were significantly associated with personal exposure product [Elemental carbon concentration, mg/m3 X time, min. (C X T)]. Data suggest that the changes in NEP activity may be an early, accurate endpoint for airway epithelial injury and provided a new insight into the mechanism of the airway effects in these exposure conditions. PMID:20384431

Pathways of human exposure to cobalt in Katanga, a mining area of the D.R. Congo.

PubMed

Cheyns, Karlien; Banza Lubaba Nkulu, Célestin; Ngombe, Léon Kabamba; Asosa, Jimmy Ngoy; Haufroid, Vincent; De Putter, Thierry; Nawrot, Tim; Kimpanga, Célestin Muleka; Numbi, Oscar Luboya; Ilunga, Benjamin Kabyla; Nemery, Benoit; Smolders, Erik

2014-08-15

Human exposure biomonitoring in the African Copperbelt (Katanga, southern D.R. Congo) revealed elevated cobalt (Co) exposure in the general population. This study was designed to identify the Co exposure routes for the non-occupationally exposed population in that area. The concentration of Co was measured in environmental and urine samples collected in urban and rural communities close to metal mining and/or refining plants, villages near a lake receiving effluents from metal refining plants, and control rural areas without industrial pollution. Drinking water, uncooked food items (maize flour, washed vegetables, fish and meat), indoor and outdoor dust samples were collected at each location. A food questionnaire was used to estimate dietary Co intake for adults and children. Geometric mean urine-Co (U-Co) concentrations were 4.5-fold (adults) and 6.6-fold (children) higher in the polluted than in the control area, with U-Co values being intermediate in the lakeside area. Average Co concentrations in environmental samples differed 6-40-fold between these areas. U-Co was positively correlated with most environmental Co concentrations, the highest correlations being found with Co in drinking water, vegetables and fruit. Estimated average total Co intake for adults was 63 (±42) μg/day in the control area, 94 (±55) μg/day in the lakeside villages and 570 (±100) μg Co/day in the polluted areas. U-Co was significantly related to modelled Co intake (R(2)=0.48, adults and R(2)=0.47, children; log-log relationship). Consumption of legumes, i.e. sweet potato leaves (polluted) and cereals+fish (lakeside) was the largest contributor to Co intake in adults, whereas dust ingestion appeared to contribute substantially in children in the polluted area. In conclusion, dietary Co is the main source of Co exposure in the polluted area and Co is efficiently transferred from soil and water in the human food chain. Copyright © 2014 Elsevier B.V. All rights reserved.

Multi-sector thermo-physiological head simulator for headgear research.

PubMed

Martinez, Natividad; Psikuta, Agnes; Corberán, José Miguel; Rossi, René M; Annaheim, Simon

2017-02-01

A novel thermo-physiological human head simulator for headgear testing was developed by coupling a thermal head manikin with a thermo-physiological model. As the heat flux at head-site is directly measured by the head manikin, this method provides a realistic quantification of the heat transfer phenomena occurring in the headgear, such as moisture absorption-desorption cycles, condensation, or moisture migration across clothing layers. Before coupling, the opportunities of the head manikin for representing the human physiology were evaluated separately. The evaluation revealed reduced precision in forehead and face temperature predictions under extreme heterogeneous temperature distributions and no initial limitation for simulating temperature changes observed in the human physiology. The thermo-physiological model predicted higher sweat rates when applied for coupled than for pure virtual simulations. After coupling, the thermo-physiological human head simulator was validated using eight human experiments. It precisely predicted core, mean skin, and forehead temperatures with average rmsd values within the average experimental standard deviation (rmsd of 0.20 ± 0.15, 0.83 ± 0.34, and 1.04 ± 0.54 °C, respectively). However, in case of forehead, precision was lower for the exposures including activity than for the sedentary exposures. The representation of the human sweat evaporation could be affected by a reduced evaporation efficiency and the manikin sweat dynamics. The industry will benefit from this thermo-physiological human head simulator leading to the development of helmet designs with enhanced thermal comfort and, therefore, with higher acceptance by users.

[Epidemiology of human rabies in China, 2016].

PubMed

Li, Y R; Zhu, L L; Zhu, W Y; Tao, X Y

2018-01-10

Objective: To understand the epidemiological characteristics of human rabies in China in 2016 and provide evidence for the control and prevention of human rabies. Methods: The incidence data of human rabies in China in 2016 were collected from national infectious disease reporting information management system. The surveillance data were collected from provinces of Shandong, Guizhou, Anhui, Hunan, Jiangsu and Guangxi Zhuang Autonomous Region. Excel 2013 software was used to process and summarize the data, the epidemiological characteristics of human rabies in China in 2016 were described by using indicators such as morbidity, mortality and constituent ratio. Results: A total of 644 human rabies cases were reported in 28 provinces in China in 2016, a decrease of 19.60% (157/801) compared with 2015. The provinces reporting high incidences of human rabies were Henan, Hunan, Guangxi and Guizhou, accounting for 39.44% (254/644) of the total cases. One case was reported in Qinghai province and Xinjiang Uygur Autonomous Region respectively. The male to female ratio of the cases was 2.14∶1 (439/205), and the majority of the patients were farmers (444/644). Surveillance points in 6 provinces reported 1 281 340 persons seeking post-exposure treatment, of whom 1 018 367 were treated for dog bite or scratch. A total of 764 234 persons completed the vaccination series, accounting for 63.90% (764 234/1 195 956) of the persons with grade Ⅱ and Ⅲ exposures, and 28.89% (165 677/573 571) of the persons with grade Ⅲ exposure were treated with passive immunization product. The average density of dogs in each surveillance area was 7.03/100 persons, the average canine immunization rate was 37.64%. Conclusion: The incidence of human rabies has remained decline in China in 2016, the number of the affected provinces has increased and that has the tendency of spreading to low-risk regions. The cases mainly occurred in men and farmers, and caused by dog bite or scratch. It is necessary to strengthen the health education about rabies prevention and control in rural areas and expand the coverage of canine immunization to prevent and control human rabies.

Assessment of indoor air quality exposures and impacts on respiratory outcomes in River Rouge and Dearborn, Michigan.

PubMed

Cleary, Erika; Asher, Mary; Olawoyin, Richard; Zhang, Kuangyuan

2017-11-01

Ambient air pollution is a public health issue which could potentially exacerbate pre-existing respiratory conditions and contribute to increases in asthma incidence. This study aims to address gaps in understanding how IAQ is impacted by outdoor air quality, which was done by sampling for indoor gaseous and particulate pollutants in residence and facilities near the sources of pollution. The study areas were selected due to non-attainment status with air quality standards, as well as demographic and socioeconomic status of those residing in these areas. Samples are obtained from five locations around the study areas. The sampling procedure involves active sampling methodologies for particulate matter (PM) and gases. Average volatile organic compounds (VOC) levels of 2.71 ppm were measured at a location, while the average particulate matter (PM) concentrations in three study locations were; 15,979 pt/cc, 9533 pt/cc, 5267 pt/cc respectively, which exceeded clean background environment level of 500-2000 pt/cc. All locations had average CO concentrations above 0.3 ppm, which is potentially associated with elevated asthma symptoms. Results demonstrated that facilities in the study area have increased levels of indoor air pollutants that potentially increase asthma and respiratory issues. The study concludes that particulate and gaseous pollutant levels in the study areas are a concerning human health issue. The study outcomes have significant implications for air quality exposure modeling and potential exposure mitigation strategies, which are expected to facilitate the implementation of public policies for improved human health conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Concentrations of synthetic musk compounds in personal care and sanitation products and human exposure profiles through dermal application.

PubMed

Roosens, Laurence; Covaci, Adrian; Neels, Hugo

2007-11-01

Synthetic musks, such as 7-acetyl-1,1,3,4,4,6-hexamethyl-1,2,3,4-tetrahydronaphthalene (AHTN) and 1,3,4,6,7,8-hexahydro-4,6,6,7,8,8-hexamethylcyclopenta-gamma-2-benzopyran (HHCB), musk ketone (MK) and musk xylene (MX), are used as an alternative for natural musk. Due to their widespread use, these synthetic compounds turned up in different environmental compartments, such as wastewater, human and animal tissues. Yet, little is known about their distribution and occurrence in personal care and household products, information needed in order to evaluate the different human exposure routes. This paper gives an overview of the synthetic musk levels in six different product categories: body lotions, perfumes, deodorants, hair care products, shower products and sanitation products. Especially body lotions, perfumes and deodorants contained high levels of synthetic musks. Maximum concentrations of HHCB, AHTN, MX and MK were 22 mg g(-1), 8 mg g(-1), 26 microg g(-1) and 0.5 microg g(-1), respectively. By combining these results with the average usage of consumer products, low-, medium- and high-exposure profiles through dermal application could be estimated. HHCB was the highest contributor to the total amount of synthetic musks in every exposure profile (18-23 700 microg d(-1)). Exposure to MK and MX did not increase substantially (10-20-fold) between low- and high-exposure profiles, indicating that these compounds cover a less broad range. In comparison, exposure to HHCB and AHTN increased up to 10 000 fold between low- and high-exposure.

Adaptive responses of the cardiovascular system to prolonged spaceflight conditions: assessment with Holter monitoring

NASA Technical Reports Server (NTRS)

Baevsky, R. M.; Bennett, B. S.; Bungo, M. W.; Charles, J. B.; Goldberger, A. L.; Nikulina, G. A.

1997-01-01

This article presents selected findings obtained with Holter monitoring from two crew members of the expedition, performed during a 175-day space mission on board orbital space station "MIR." Using mathematical processing of daily cardiointervals files, 5-minute sections of records were analyzed consecutively. Then, the average daily values of indices, the average-per-every-eight-hours values (morning, evening, night) and mean values per hour were computed. The results of analysis showed that prolonged exposure of man to microgravity conditions leads to important functional alteration in human neuroautonomic regulatory mechanisms. Both crew members had significant increase of heart rate, the rise of stress index, the decrease in power of the spectrum in the range of respiratory sinus arrhythmia. These marked signs of activation of the sympathetic section of the vegetative nervous system showed individual variations. The analysis of the daily collection of cardiointervals with Holter monitoring allows us to understand and forecast the functional feasibilities of the human organism under a variety of stress conditions associated with acute and chronic microgravity exposure.

Computational Fluid Dynamics Modeling of Bacillus anthracis ...

EPA Pesticide Factsheets

Journal Article Three-dimensional computational fluid dynamics and Lagrangian particle deposition models were developed to compare the deposition of aerosolized Bacillus anthracis spores in the respiratory airways of a human with that of the rabbit, a species commonly used in the study of anthrax disease. The respiratory airway geometries for each species were derived from computed tomography (CT) or µCT images. Both models encompassed airways that extended from the external nose to the lung with a total of 272 outlets in the human model and 2878 outlets in the rabbit model. All simulations of spore deposition were conducted under transient, inhalation-exhalation breathing conditions using average species-specific minute volumes. Four different exposure scenarios were modeled in the rabbit based upon experimental inhalation studies. For comparison, human simulations were conducted at the highest exposure concentration used during the rabbit experimental exposures. Results demonstrated that regional spore deposition patterns were sensitive to airway geometry and ventilation profiles. Despite the complex airway geometries in the rabbit nose, higher spore deposition efficiency was predicted in the upper conducting airways of the human at the same air concentration of anthrax spores. This greater deposition of spores in the upper airways in the human resulted in lower penetration and deposition in the tracheobronchial airways and the deep lung than that predict

Changes in photoinduced cutaneous erythema with topical application of a combination of vitamins C and E before and after UV exposure.

PubMed

Aguilera, José; de Gálvez, María Victoria; Sánchez, Cristina; Herrera-Ceballos, Enrique

2012-06-01

Ultraviolet radiation is harmful for human skin, and photodamaging pathologies such as actinic erythema, are formerly described as a consequence of UV direct effect on DNA and indirectly by local immune reactions. However, the degree of participation of oxidative stress in actinic erythema and the role of antioxidants in photoprotection are still not fully understood. To evaluate the possible palliative role of a combination of the antioxidants vitamins C and E in human cutaneous erythema when applied topically before and after UV exposure. The study included 20 volunteers of phototypes II, II-III and III with no solar exposure for two months prior to the study. The volunteers were submitted to a phototest consisting on the analysis of the minimal erythemal dose (MED) under different treatments: 1. Untreated irradiated skin; 2. Irradiated skin previously treated with vehicle; 3. Irradiated skin previously treated with a combination of vitamins (2.5% vit E-5% vit C); and 4. Skin treated with the antioxidant combination after irradiation. Cutaneous erythema was evaluated 24h after exposure and the MED was calculated for each treatment. The application of vehicle did not significantly affect the MED compared to untreated irradiated skin. Application of the antioxidant combination, prior to irradiation, increased the MED in all phototypes compared with untreated irradiated skin with an average increase of 36.9%. Antioxidants applied after exposure promoted an average increase of the MED by 19.8%. Combination of topical antioxidants (vitamins C and E) shows photoprotection activity against erythema, mainly owing to their high absorption properties. Moreover, their antioxidant activity could be considered as additive, and independent of their optical properties. Copyright © 2012 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

An acarologic survey and Amblyomma americanum distribution map with implications for tularemia risk in Missouri

USGS Publications Warehouse

Brown, H.E.; Yates, K.F.; Dietrich, G.; MacMillan, K.; Graham, C.B.; Reese, S.M.; Helterbrand, Wm. S.; Nicholson, W.L.; Blount, K.; Mead, P.S.; Patrick, S.L.; Eisen, R.J.

2011-01-01

In the United States, tickborne diseases occur focally. Missouri represents a major focus of several tickborne diseases that includes spotted fever rickettsiosis, tularemia, and ehrlichiosis. Our study sought to determine the potential risk of human exposure to human-biting vector ticks in this area. We collected ticks in 79 sites in southern Missouri during June 7-10, 2009, which yielded 1,047 adult and 3,585 nymphal Amblyomma americanum, 5 adult Amblyomma maculatum, 19 adult Dermacentor variabilis, and 5 nymphal Ixodes brunneus. Logistic regression analysis showed that areas posing an elevated risk of exposure to A. americanum nymphs or adults were more likely to be classified as forested than grassland, and the probability of being classified as elevated risk increased with increasing relative humidity during the month of June (30-year average). Overall accuracy of each of the two models was greater than 70% and showed that 20% and 30% of the state were classified as elevated risk for human exposure to nymphs and adults, respectively. We also found a significant positive association between heightened acarologic risk and counties reporting tularemia cases. Our study provides an updated distribution map for A. americanum in Missouri and suggests a wide-spread risk of human exposure to A. americanum and their associated pathogens in this region. Copyright ?? 2011 by The American Society of Tropical Medicine and Hygiene.

Using probabilistic modeling to evaluate human exposure to organotin in drinking water transported by polyvinyl chloride pipe.

PubMed

Fristachi, Anthony; Xu, Ying; Rice, Glenn; Impellitteri, Christopher A; Carlson-Lynch, Heather; Little, John C

2009-11-01

The leaching of organotin (OT) heat stabilizers from polyvinyl chloride (PVC) pipes used in residential drinking water systems may affect the quality of drinking water. These OTs, principally mono- and di-substituted species of butyltins and methyltins, are a potential health concern because they belong to a broad class of compounds that may be immune, nervous, and reproductive system toxicants. In this article, we develop probability distributions of U.S. population exposures to mixtures of OTs encountered in drinking water transported by PVC pipes. We employed a family of mathematical models to estimate OT leaching rates from PVC pipe as a function of both surface area and time. We then integrated the distribution of estimated leaching rates into an exposure model that estimated the probability distribution of OT concentrations in tap waters and the resulting potential human OT exposures via tap water consumption. Our study results suggest that human OT exposures through tap water consumption are likely to be considerably lower than the World Health Organization (WHO) "safe" long-term concentration in drinking water (150 microg/L) for dibutyltin (DBT)--the most toxic of the OT considered in this article. The 90th percentile average daily dose (ADD) estimate of 0.034 +/- 2.92 x 10(-4)microg/kg day is approximately 120 times lower than the WHO-based ADD for DBT (4.2 microg/kg day).

Modelling of human exposure to air pollution in the urban environment: a GPS-based approach.

PubMed

Dias, Daniela; Tchepel, Oxana

2014-03-01

The main objective of this work was the development of a new modelling tool for quantification of human exposure to traffic-related air pollution within distinct microenvironments by using a novel approach for trajectory analysis of the individuals. For this purpose, mobile phones with Global Positioning System technology have been used to collect daily trajectories of the individuals with higher temporal resolution and a trajectory data mining, and geo-spatial analysis algorithm was developed and implemented within a Geographical Information System to obtain time-activity patterns. These data were combined with air pollutant concentrations estimated for several microenvironments. In addition to outdoor, pollutant concentrations in distinct indoor microenvironments are characterised using a probabilistic approach. An example of the application for PM2.5 is presented and discussed. The results obtained for daily average individual exposure correspond to a mean value of 10.6 and 6.0-16.4 μg m(-3) in terms of 5th-95th percentiles. Analysis of the results shows that the use of point air quality measurements for exposure assessment will not explain the intra- and inter-variability of individuals' exposure levels. The methodology developed and implemented in this work provides time-sequence of the exposure events thus making possible association of the exposure with the individual activities and delivers main statistics on individual's air pollution exposure with high spatio-temporal resolution.

Analysis of linear energy transfers and quality factors of charged particles produced by spontaneous fission neutrons from 252Cf and 244Pu in the human body.

PubMed

Endo, Akira; Sato, Tatsuhiko

2013-04-01

Absorbed doses, linear energy transfers (LETs) and quality factors of secondary charged particles in organs and tissues, generated via the interactions of the spontaneous fission neutrons from (252)Cf and (244)Pu within the human body, were studied using the Particle and Heavy Ion Transport Code System (PHITS) coupled with the ICRP Reference Phantom. Both the absorbed doses and the quality factors in target organs generally decrease with increasing distance from the source organ. The analysis of LET distributions of secondary charged particles led to the identification of the relationship between LET spectra and target-source organ locations. A comparison between human body-averaged mean quality factors and fluence-averaged radiation weighting factors showed that the current numerical conventions for the radiation weighting factors of neutrons, updated in ICRP103, and the quality factors for internal exposure are valid.

Phase-shifting human circadian rhythms: influence of sleep timing, social contact and light exposure

NASA Technical Reports Server (NTRS)

Duffy, J. F.; Kronauer, R. E.; Czeisler, C. A.

1996-01-01

1. Both the timing of behavioural events (activity, sleep and social interactions) and the environmental light-dark cycle have been reported to contribute to entrainment of human circadian rhythms to the 24 h day. Yet, the relative contribution of those putative behavioural synchronizers to that of light exposure remains unclear. 2. To investigate this, we inverted the schedule of rest, sedentary activity and social contact of thirty-two young men either with or without exposure to bright light. 3. On this inverted schedule, the endogenous component of the core temperature rhythm of subjects who were exposed to bright light showed a significant phase shift, demonstrating that they were adapting to the new schedule. In contrast, the core temperature rhythm of subjects who were not exposed to bright light moved on average 0.2 h later per day and after 10 days had not significantly adapted to the new schedule. 4. The direction of phase shift in the groups exposed to bright light was dependent on the time of bright light exposure, while control subjects drifted to a later hour regardless of the timing of their schedule of sleep timing, social contact and meals. 5. These results support the concept that the light-dark cycle is the most important synchronizer of the human circadian system. They suggest that inversion of the sleep-wake, rest-activity and social contact cycles provides relatively minimal drive for resetting the human circadian pacemaker. 6. These data indicate that interventions designed to phase shift human circadian rhythms for adjustment to time zone changes or altered work schedules should focus on properly timed light exposure.

A Preliminary Study of Biomonitoring for Bisphenol-A in Human Sweat.

PubMed

Porucznik, Christina A; Cox, Kyley J; Wilkins, Diana G; Anderson, David J; Bailey, Nicole M; Szczotka, Kathryn M; Stanford, Joseph B

2015-09-01

Measurement of human exposure to the endocrine disruptor bisphenol-A (BPA) is hampered by the ubiquitous but transient exposure for most individuals, coupled with a short metabolic half-life which leads to high inter- and intra-individual variability. We investigated the possibility of measuring multiday exposure to BPA in human sweat among volunteer participants with the goal of identifying an exposure assessment method less affected by temporal variability. We recruited 50 participants to wear a sweat collection patch (PharmChek(®)) for 7 days with concurrent collection of daily first-morning urine. Urines and sweat patch extracts were analyzed with quantitative LC-MS-MS using a method we previously validated. In addition, a human volunteer consumed one can of commercially available soup (16 oz, 473 cm(3)) daily for 3 days and collected urine. Sweat patches (n = 2, 1 per arm) were worn for the 3 days of the study. BPA was detected in quality control specimens prepared by fortification of BPA to sweat patches, but was only detected at 5× above average background on three participant patches. Although the highest measured urine BPA concentration was 195 ng/mL for an individual with deliberate exposure, no BPA was detected above background in the corresponding sweat patches. In this preliminary investigation, the use of sweat patches primarily worn on the upper-outer arm did not detect BPA exposures that were documented by urine monitoring. The absence of BPA in sweat patches may be due to several factors, including insufficient quantity of specimen per patch, or extremely low concentrations of BPA in naturally occurring sweat, among others. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Human biomonitoring pilot study DEMOCOPHES in Germany: Contribution to a harmonized European approach.

PubMed

Schwedler, Gerda; Seiwert, Margarete; Fiddicke, Ulrike; Ißleb, Sissy; Hölzer, Jürgen; Nendza, Julia; Wilhelm, Michael; Wittsiepe, Jürgen; Koch, Holger M; Schindler, Birgit K; Göen, Thomas; Hildebrand, Jörg; Joas, Reinhard; Joas, Anke; Casteleyn, Ludwine; Angerer, Jürgen; Castano, Argelia; Esteban, Marta; Schoeters, Greet; Den Hond, Elly; Sepai, Ovnair; Exley, Karen; Bloemen, Louis; Knudsen, Lisbeth E; Kolossa-Gehring, Marike

2017-06-01

Human biomonitoring (HBM) is an effective tool to assess human exposure to environmental pollutants, but comparable HBM data in Europe are lacking. In order to expedite harmonization of HBM studies on a European scale, the twin projects COPHES (Consortium to Perform Human Biomonitoring on a European Scale) and DEMOCOPHES (Demonstration of a study to Coordinate and Perform Human Biomonitoring on a European Scale) were formed, comprising 35 partners from 27 European countries. In COPHES a research scheme and guidelines were developed to exemplarily measure in a pilot study mercury in hair, cadmium, cotinine and several phthalate metabolites in urine of 6-11year old children and their mothers in an urban and a rural region. Seventeen European countries simultaneously conducted this cross-sectional DEMOCOPHES feasibility study. The German study population was taken in the city of Bochum and in the Higher Sauerland District, comprising 120 mother-child pairs. In the present paper features of the study implementation are presented. German exposure concentrations of the pollutants are reported and compared with European average concentrations from DEMOCOPHES and with those measured in the representative German Environmental Survey (GerES IV). German DEMOCOPHES concentrations for mercury and cotinine were lower than the European average. However, 47% of the children were still exposed to environmental tobacco smoke (ETS) outside their home, which gives further potential for enhancing protection of children from ETS. Compared with samples from the other European countries German participating children had lower concentrations of the phthalate metabolites MEP and of the sum of 3 DEHP-metabolites (MEHP, 5OH-MEHP and 5oxo-MEHP), about the same concentrations of the phthalate metabolites MBzP and MiBP and higher concentrations of the phthalate metabolite MnBP. 2.5% of the German children had concentrations of the sum of 4 DEHP-metabolites and 4.2% had concentrations of MnBP that exceeded health based guidance values, indicating reasons for concern. Continuous HBM is necessary to track changes of pollutant exposure over time. Therefore Germany will continue to cooperate on the harmonisation of European human biomonitoring to support the chemicals regulation with the best possible exposure data to protect Europe's people against environmental health risks. Copyright © 2017 The Authors. Published by Elsevier GmbH.. All rights reserved.

Effects of methanol vapor on human neurobehavioral measures. Research report, Jul 88-Oct 90

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

Cook, M.R.; Bergman, F.J.; Cohen, H.D.

1991-01-01

Methanol may become an important alternative fuel for vehicles in the near future. The objective of the preliminary study was to determine if inhalation exposure to methanol, near the maximum concentration allowed for an eight-hour average exposure in the workplace (200 ppm), would have adverse effects on human neurobehavioral functions. Twelve healthy young men were exposed twice to filtered air and twice to 192 ppm methanol vapors for 75 minutes on different days under double-blind conditions. Twenty-two neurobehavioral and neurophysiological tests were administered before, during, and after exposure to measure visual, behavioral, reasoning, and hearing functions. Exposure to methanol producedmore » significant increases in blood and urine methanol concentration at the end of the exposure period. As expected, no changes in plasma formate were observed. Methanol exposure had no effect on the subjects' performance on most of the tests. However, some methanol-exposed subjects reported more fatigue and lack of concentration. Performance was also slightly impaired on the Sternberg memory task. There were also changes in the latency of the P200 component of the visual- and auditory-event related potential. These effects were small and did not exceed the range of results measured in filtered air-exposed subjects.« less

Effects of m-xylene on human equilibrium measured with a quantitative method.

PubMed

Savolainen, K; Linnavuo, M

1979-04-01

Swaying during normal upright posture in 17 young males and the effects of m-xylene exposure on the body sway of six of the 17 has been studied by a quantitative Romberg test, conducted with an equipment consisting of a strain gauge transducer platform and of an electronic unit. The exposures were conducted in a dynamic exposure chamber. The sway of the 17 subjects was larger when their eyes were closed than when they were open (P less than 0.001) indicating the importance of vision in the control of body balance. Exposure to a time-weighted average (TWA) concentration of 100 p.p.m. (4.1 mumol/l) of xylene with 200 p.p.m. (8.2 mumol/l) peaks had no observable effect on the body balance of the six subjects. Exposure to a TWA concentration of 200 p.p.m. of xylene with 400 p.p.m. (16.4 mumol/l) peaks--the corresponding mean concentration of xylene in venous blood being 29.1 +/- 3.2 mumol/l--clearly impaired the body balance of the six subjects. The impairment was most pronounced with the eyes closed (P = 0.016). The results suggest that human equilibrium is rather sensitive to effects of exposure to xylene.

Geochemical Legacies and the Future Health of Cities: An Analysis of two Neurotoxins in Urban Soils

NASA Astrophysics Data System (ADS)

Filippelli, G. M.; Risch, M.

2015-12-01

The past and future of cities are inextricably linked, a linkage that can be seen clearly in the long-term impacts of urban geochemical legacies. As loci of population as well as the means of employment and industry to support these populations, cities have a long history of co-locating contaminating practices and people, sometimes with negative implications for human health. Working at the intersection between geochemical processes, communities, and human health is critical to grapple with environmental legacies and to support healthy, sustainable, and growing urban populations. An emerging area of environmental health research is to understand the impacts of chronic exposures and exposure mixtures—these impacts are very poorly studied, yet have materialized as perhaps the greatest threat to large-scale population health. Acute exposure to lead (Pb), a powerful neurotoxin to which children are particularly susceptible, has largely been eliminated in the U.S. and other countries through policy-based restrictions on leaded gasoline and lead-based paints. But these legacy Pb sources are still around in the form of surface soil Pb contamination, a common problem in cities and one that has only recently emerged as a pernicious and widespread chronic exposure mechanism in cities. Some urban soils are also contaminated with another neurotoxin, mercury (Hg), although very little work has been done to understand human exposures to low levels of this element in soils. The most documented human exposure to Hg is through fish consumption, so eating fish caught in urban areas presents risks for above average dietary Hg exposure. The potential double impact of chronic exposure to these two neurotoxins is pronounced in cities. Many aspects of the dose-response curves for individual elements and mixtures are poorly understood, especially at lower levels, leaving unanswered several interesting and provocative questions about environmental impacts on neurological and developmental disorders.

Biodiesel exhaust-induced cytotoxicity and proinflammatory mediator production in human airway epithelial cells.

PubMed

Mullins, Benjamin J; Kicic, Anthony; Ling, Kak-Ming; Mead-Hunter, Ryan; Larcombe, Alexander N

2016-01-01

Increasing use of biodiesel has prompted research into the potential health effects of biodiesel exhaust exposure. Few studies directly compare the health consequences of mineral diesel, biodiesel, or blend exhaust exposures. Here, we exposed human epithelial cell cultures to diluted exhaust generated by the combustion of Australian ultralow-sulfur-diesel (ULSD), unprocessed canola oil, 100% canola biodiesel (B100), and a blend of 20% canola biodiesel mixed with 80% ULSD. The physicochemical characteristics of the exhaust were assessed and we compared cellular viability, apoptosis, and levels of interleukin (IL)-6, IL-8, and Regulated on Activation, Normal T cell Expressed and Secreted (RANTES) in exposed cultured cells. Different fuel types produced significantly different amounts of exhaust gases and different particle characteristics. All exposures resulted in significant apoptosis and loss of viability when compared with control, with an increasing proportion of biodiesel being correlated with a decrease in viability. In most cases, exposure to exhaust resulted in an increase in mediator production, with the greatest increases most often in response to B100. Exposure to pure canola oil (PCO) exhaust did not increase mediator production, but resulted in a significant decrease in IL-8 and RANTES in some cases. Our results show that canola biodiesel exhaust exposure elicits inflammation and reduces viability of human epithelial cell cultures in vitro when compared with ULSD exhaust exposure. This may be related to an increase in particle surface area and number in B100 exhaust when compared with ULSD exhaust. Exposure to PCO exhaust elicited the greatest loss of cellular viability, but virtually no inflammatory response, likely due to an overall increase in average particle size. © 2014 Wiley Periodicals, Inc.

Poly- and perfluoroalkylated substances (PFASs) in water, sediment and fish muscle tissue from Lake Tana, Ethiopia and implications for human exposure.

PubMed

Ahrens, Lutz; Gashaw, Habiba; Sjöholm, Margareta; Gebrehiwot, Solomon Gebreyohannis; Getahun, Abebe; Derbe, Ermias; Bishop, Kevin; Åkerblom, Staffan

2016-12-01

Lake Tana is Ethiopia's largest lake and there are plans to increase the harvest of fish from the lake. The objective of this study was to assess the levels of poly- and perfluoroalkyl substances (PFASs) in different compartments of the lake (water, sediment, and fish muscle tissue), and its implications for human exposure. The results showed higher PFAS concentrations in piscivorous fish species (Labeobarbus megastoma and Labeobarbus gorguari) than non-piscivorous species (Labeobarbus intermedius, Oreochromis niloticus and Clarias gariepinus) and also spatial distribution similarities. The ∑PFAS concentrations ranged from 0.073 to 5.6 ng L -1 (on average, 2.9 ng L -1 ) in surface water, 0.22-0.55 ng g -1 dry weight (dw) (on average, 0.30 ng g -1 dw) in surface sediment, and non-detected to 5.8 ng g -1 wet weight (ww) (on average, 1.2 ng g -1 ww) in all fish species. The relative risk (RR) indicates that the consumption of fish contaminated with perfluorooctane sulfonate (PFOS) will likely not cause any harmful effects for the Ethiopian fish eating population. However, mixture toxicity of the sum of PFASs, individual fish consumption patterns and increasing fish consumption are important factors to consider in future risk assessments. Copyright © 2016 Elsevier Ltd. All rights reserved.

Dietary exposure estimates of twenty-one trace elements from a Total Diet Study carried out in Pavia, Northern Italy.

PubMed

Turconi, Giovanna; Minoia, Claudio; Ronchi, Anna; Roggi, Carla

2009-04-01

The significant role of trace elements in human health is well documented. Trace elements are those compounds that need to be present in the human diet to maintain normal physiological functions. However, some microelements may become harmful at high levels of exposure, or, on the other hand, may give rise to malnutrition, when their exposure is too low. The aim of the present study was to provide a reliable estimate of the dietary exposure of twenty-one trace elements in a Northern Italian area. For this purpose, trace element analyses were undertaken on total diet samples collected from a university cafeteria in Pavia, Northern Italy. The average daily exposure for the adult people was calculated on the basis of food consumption frequency, portion size and trace element levels in foodstuffs. The mean exposure values satisfy the Italian RDA for all the essential trace elements, except for Fe exposure in females, and are well below the Provisional Tolerable Daily Intake for all the toxic compounds, showing that the probability of dietary exposure to health risks is overall small. As far as Fe exposure is concerned, a potential risk of anaemia in the female adult population should be considered, then studies aimed at evaluating the Fe nutritional status of adult Italian women should be addressed. In conclusion, while not excluding the possibility that the daily exposure determined in the present study may not be representative of the population as a whole, this study provides a good estimate of the Italian adult consumer exposure to twenty-one trace elements.

Human exposure to power frequency magnetic fields up to 7.6 mT: An integrated EEG/fMRI study.

PubMed

Modolo, Julien; Thomas, Alex W; Legros, Alexandre

2017-09-01

We assessed the effects of power-line frequency (60 Hz in North America) magnetic fields (MF) in humans using simultaneous electroencephalography (EEG) and functional magnetic resonance imaging (fMRI). Twenty-five participants were enrolled in a pseudo-double-blind experiment involving "real" or "sham" exposure to sinusoidal 60 Hz MF exposures delivered using the gradient coil of an MRI scanner following two conditions: (i) 10 s exposures at 3 mT (10 repetitions); (ii) 2 s exposures at 7.6 mT (100 repetitions). Occipital EEG spectral power was computed in the alpha range (8-12 Hz, reportedly the most sensitive to MF exposure in the literature) with/without exposure. Brain functional activation was studied using fMRI blood oxygen level-dependent (BOLD, inversely correlated with EEG alpha power) maps. No significant effects were detected on occipital EEG alpha power during or post-exposure for any exposure condition. Consistent with EEG results, no effects were observed on fMRI BOLD maps in any brain region. Our results suggest that acute exposure (2-10 s) to 60 Hz MF from 3 to 7.6 mT (30,000 to 76,000 times higher than average public exposure levels for 60 Hz MF) does not induce detectable changes in EEG or BOLD signals. Combined with previous findings in which effects were observed on the BOLD signal after 1 h exposure to 3 mT, 60 Hz MF, this suggests that MF exposure in the low mT range (<10 mT) might require prolonged durations of exposure to induce detectable effects. Bioelectromagnetics. 38:425-435, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

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

NASA Astrophysics Data System (ADS)

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.

Naphthalene distributions and human exposure in Southern California

NASA Astrophysics Data System (ADS)

Lu, Rong; Wu, Jun; Turco, Richard P.; Winer, Arthur M.; Atkinson, Roger; Arey, Janet; Paulson, Suzanne E.; Lurmann, Fred W.; Miguel, Antonio H.; Eiguren-Fernandez, Arantzazu

The regional distribution of, and human exposure to, naphthalene are investigated for Southern California. A comprehensive approach is taken in which advanced models are linked for the first time to quantify population exposure to the emissions of naphthalene throughout Southern California. Naphthalene is the simplest and most abundant of the polycyclic aromatic hydrocarbons found in polluted urban environments, and has been detected in both outdoor and indoor air samples. Exposure to high concentrations of naphthalene may have adverse health effects, possibly causing cancer in humans. Among the significant emission sources are volatilization from naphthalene-containing products, petroleum refining, and combustion of fossil fuels and wood. Gasoline and diesel engine exhaust, with related vaporization from fuels, are found to contribute roughly half of the daily total naphthalene burden in Southern California. As part of this study, the emission inventory for naphthalene has been verified against new field measurements of the naphthalene-to-benzene ratio in a busy traffic tunnel in Los Angeles, supporting the modeling work carried out here. The Surface Meteorology and Ozone Generation (SMOG) airshed model is used to compute the spatial and temporal distributions of naphthalene and its photooxidation products in Southern California. The present simulations reveal a high degree of spatial variability in the concentrations of naphthalene-related species, with large diurnal and seasonal variations as well. Peak naphthalene concentrations are estimated to occur in the early morning hours in the winter season. The naphthalene concentration estimates obtained from the SMOG model are employed in the Regional Human Exposure (REHEX) model to calculate population exposure statistics. Results show average hourly naphthalene exposures in Southern California under summer and winter conditions of 270 and 430 ng m -3, respectively. Exposure to significantly higher concentrations may occur for individuals close to local sources, or in naphthalene "hotspots" revealed by simulations and observations. Such levels of naphthalene exposure may be used to gauge the potential health impacts of long-term naphthalene exposure. Results are also given for the distributions of 1,4-naphthoquinone, a naphthalene reaction product that may have significant health effects.

Exposure system to study hypotheses of ELF and RF electromagnetic field interactions of mobile phones with the central nervous system.

PubMed

Murbach, Manuel; Christopoulou, Maria; Crespo-Valero, Pedro; Achermann, Peter; Kuster, Niels

2012-09-01

A novel exposure system for double-blind human electromagnetic provocation studies has been developed that satisfies the precision, control of fields and potential artifacts, and provides the flexibility to investigate the response of hypotheses-driven electromagnetic field exposure schemes on brain function, ranging from extremely low frequency (ELF) to radio frequency (RF) fields. The system can provide the same exposure of the lateral cerebral cortex at two different RF frequencies (900 and 2140 MHz) but with different exposure levels at subcortical structures, and also allows uniform ELF magnetic field exposure of the brain. The RF modulation and ELF signal are obtained by a freely programmable arbitrary signal generator allowing a wide range of worst-case exposure scenarios to be simulated, including those caused by wireless devices. The maximum achievable RF exposure is larger than 60 W/kg peak spatial specific absorption rate averaged over 10 g of tissue. The maximum ELF magnetic field exposure of the brain is 800 A/m at 50 Hz with a deviation from uniformity of 8% (SD). Copyright © 2012 Wiley Periodicals, Inc.

Assessment of human deoxynivalenol exposure using an LC-MS/MS based biomarker method.

PubMed

Warth, Benedikt; Sulyok, Michael; Fruhmann, Philipp; Berthiller, Franz; Schuhmacher, Rainer; Hametner, Christian; Adam, Gerhard; Fröhlich, Johannes; Krska, Rudolf

2012-05-20

The Fusarium toxin deoxynivalenol (DON) is one of the most abundant mycotoxins worldwide and poses many adverse health effects to human and animals. Consequently, regulatory limits and a provisional maximum tolerable daily intake (PMTDI) for this important type B-trichothecene were assigned. We conducted a pilot survey to investigate the level of DON exposure in Austrian adults by measurements of DON and its glucuronide conjugates (DON-GlcA's), as biomarkers of exposure, in first morning urine. The average concentration of total DON (free DON+DON-GlcA's) was estimated to be 20.4±2.4 μg L⁻¹ (max. 63 μg L⁻¹). Surprisingly, we found that one third of the volunteers (n=27) exceeded the established PMTDI when consuming regular diet. DON-GlcA's were directly quantified by LC-MS/MS and the results were compared with indirect quantification after enzymatic hydrolysis and confirmed the suitability of the direct method. Moreover, we investigated the in vivo metabolism of DON in humans and were able to determine two closely eluting DON-GlcA's in naturally contaminated urine samples for the first time. In contrast to previous findings we have tentatively identified DON-15-glucuronide as a major DON metabolite in human urine based on the analysis of these samples. About 75% of total glucuronides were derived from this metabolite while DON-3-glucuronide accounted for approximately 25%. The reported new findings clearly demonstrate the great potential of suitable biomarkers to critically assess exposure of humans and animals to DON. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

Diffusion Tensor Imaging of Frontal White Matter and Executive Functioning in Cocaine-Exposed Children

PubMed Central

Warner, Tamara Duckworth; Behnke, Marylou; Eyler, Fonda Davis; Padgett, Kyle; Leonard, Christiana; Hou, Wei; Garvan, Cynthia Wilson; Schmalfuss, Ilona M.; Blackband, Stephen J.

2011-01-01

BACKGROUND Although animal studies have demonstrated frontal white matter and behavioral changes resulting from prenatal cocaine exposure, no human studies have associated neuropsychological deficits in attention and inhibition with brain structure. We used diffusion tensor imaging to investigate frontal white matter integrity and executive functioning in cocaine-exposed children. METHODS Six direction diffusion tensor images were acquired using a Siemens 3T scanner with a spin-echo echo-planar imaging pulse sequence on right-handed cocaine-exposed (n = 28) and sociodemographically similar non-exposed children (n = 25; mean age: 10.6 years) drawn from a prospective, longitudinal study. Average diffusion and fractional anisotropy were measured in the left and right frontal callosal and frontal projection fibers. Executive functioning was assessed using two well-validated neuropsychological tests (Stroop color-word test and Trail Making Test). RESULTS Cocaine-exposed children showed significantly higher average diffusion in the left frontal callosal and right frontal projection fibers. Cocaine-exposed children were also significantly slower on a visual-motor set-shifting task with a trend toward lower scores on a verbal inhibition task. Controlling for gender and intelligence, average diffusion in the left frontal callosal fibers was related to prenatal exposure to alcohol and marijuana and an interaction between cocaine and marijuana exposure. Performance on the visual-motor set-shifting task was related to prenatal cocaine exposure and an interaction between cocaine and tobacco exposure. Significant correlations were found between test performance and fractional anisotropy in areas of the frontal white matter. CONCLUSIONS Prenatal cocaine exposure, alone and in combination with exposure to other drugs, is associated with slightly poorer executive functioning and subtle microstructural changes suggesting less mature development of frontal white matter pathways. The relative contribution of postnatal environmental factors, including characteristics of the caregiving environment and stressors associated with poverty and out-of-home placement, on brain development and behavioral functioning in polydrug-exposed children awaits further research. PMID:17079574

Diffusion tensor imaging of frontal white matter and executive functioning in cocaine-exposed children.

PubMed

Warner, Tamara Duckworth; Behnke, Marylou; Eyler, Fonda Davis; Padgett, Kyle; Leonard, Christiana; Hou, Wei; Garvan, Cynthia Wilson; Schmalfuss, Ilona M; Blackband, Stephen J

2006-11-01

Although animal studies have demonstrated frontal white matter and behavioral changes resulting from prenatal cocaine exposure, no human studies have associated neuropsychological deficits in attention and inhibition with brain structure. We used diffusion tensor imaging to investigate frontal white matter integrity and executive functioning in cocaine-exposed children. Six direction diffusion tensor images were acquired using a Siemens 3T scanner with a spin-echo echo-planar imaging pulse sequence on right-handed cocaine-exposed (n = 28) and sociodemographically similar non-exposed children (n = 25; mean age: 10.6 years) drawn from a prospective, longitudinal study. Average diffusion and fractional anisotropy were measured in the left and right frontal callosal and frontal projection fibers. Executive functioning was assessed using two well-validated neuropsychological tests (Stroop color-word test and Trail Making Test). Cocaine-exposed children showed significantly higher average diffusion in the left frontal callosal and right frontal projection fibers. Cocaine-exposed children were also significantly slower on a visual-motor set-shifting task with a trend toward lower scores on a verbal inhibition task. Controlling for gender and intelligence, average diffusion in the left frontal callosal fibers was related to prenatal exposure to alcohol and marijuana and an interaction between cocaine and marijuana exposure. Performance on the visual-motor set-shifting task was related to prenatal cocaine exposure and an interaction between cocaine and tobacco exposure. Significant correlations were found between test performance and fractional anisotropy in areas of the frontal white matter. Prenatal cocaine exposure, alone and in combination with exposure to other drugs, is associated with slightly poorer executive functioning and subtle microstructural changes suggesting less mature development of frontal white matter pathways. The relative contribution of postnatal environmental factors, including characteristics of the caregiving environment and stressors associated with poverty and out-of-home placement, on brain development and behavioral functioning in polydrug-exposed children awaits further research.

Effects of acute exercise on fear extinction in rats and exposure therapy in humans: Null findings from five experiments.

PubMed

Jacquart, Jolene; Roquet, Rheall F; Papini, Santiago; Powers, Mark B; Rosenfield, David; Smits, Jasper A J; Monfils, Marie-H

2017-08-01

Exposure therapy is an established learning-based intervention for the treatment of anxiety disorders with an average response rate of nearly 50%, leaving room for improvement. Emerging strategies to enhance exposure therapy in humans and fear extinction retention in animal models are primarily pharmacological. These approaches are limited as many patients report preferring non-pharmacological approaches in therapy. With general cognitive enhancement effects, exercise has emerged as a plausible non-pharmacological augmentation strategy. The present study tested the hypothesis that fear extinction and exposure therapy would be enhanced by a pre-training bout of exercise. We conducted four experiments with rats that involved a standardized conditioning and extinction paradigm and a manipulation of exercise. In a fifth experiment, we manipulated vigorous-intensity exercise prior to a standardized virtual reality exposure therapy session among adults with fear of heights. In experiments 1-4, exercise did not facilitate fear extinction, long-term memory, or fear relapse tests. In experiment 5, human participants showed an overall reduction in fear of heights but exercise did not enhance symptom improvement. Although acute exercise prior to fear extinction or exposure therapy, as operationalized in the present 5 studies, did not enhance outcomes, these results must be interpreted within the context of a broader literature that includes positive findings. Taken all together, this suggests that more research is necessary to identify optimal parameters and key individual differences so that exercise can be implemented successfully to treat anxiety disorders. Copyright © 2017 Elsevier Ltd. All rights reserved.

Measurement systems and indices of miners' exposure to radon daughter products in the air of mines.

PubMed

Domański, T

1990-01-01

This paper presents the classification of measurement systems that may be used for the assessment of miners' exposure to radiation in mines. The following systems were described and characterized as the Air Sampling System (ASS), the Environmental Control System (ECS), the Individual Dosimetry System (IDS), the Stream Monitoring System (SMS) and the Exhaust Monitoring System (EMS). The indices for evaluation of miners' working environments, or for assessment of individual or collective miners' exposure, were selected and determined. These are: average expected concentration (CAE), average observed concentration (CAO), average expected rate of exposure cumulation rate (EEXP), average observed exposure cumulation rate (EOBS), average effective exposure cumulation rate (EEFF). Mathematical formulae for determining all these indicators, according to the type of measurement system used in particular mines, are presented. The reliability of assessment of miners' exposure in particular measurement systems, as well as the role of the possible reference system, are discussed.

A review of historical exposures to asbestos among skilled craftsmen (1940-2006).

PubMed

Williams, Pamela R D; Phelka, Amanda D; Paustenbach, Dennis J

2007-01-01

This article provides a review and synthesis of the published and selected unpublished literature on historical asbestos exposures among skilled craftsmen in various nonshipyard and shipyard settings. The specific crafts evaluated were insulators, pipefitters, boilermakers, masons, welders, sheet-metal workers, millwrights, electricians, carpenters, painters, laborers, maintenance workers, and abatement workers. Over 50 documents were identified and summarized. Sufficient information was available to quantitatively characterize historical asbestos exposures for the most highly exposed workers (insulators), even though data were lacking for some job tasks or time periods. Average airborne fiber concentrations collected for the duration of the task and/or the entire work shift were found to range from about 2 to 10 fibers per cubic centimeter (cm3 or cc) during activities performed by insulators in various nonshipyard settings from the late 1960s and early 1970s. Higher exposure levels were observed for this craft during the 1940s to 1950s, when dust counts were converted from millions of particles per cubic foot (mppcf) to units of fibers per cubic centimeter (fibers/cc) using a 1:6 conversion factor. Similar tasks performed in U.S. shipyards yielded average fiber concentrations about two-fold greater, likely due to inadequate ventilation and confined work environments; however, excessively high exposure levels were reported in some British Naval shipyards due to the spraying of asbestos. Improved industrial hygiene practices initiated in the early to mid-1970s were found to reduce average fiber concentrations for insulator tasks approximately two- to five-fold. For most other crafts, average fiber concentrations were found to typically range from <0.01 to 1 fibers/cc (depending on the task or time period), with higher concentrations observed during the use of powered tools, the mixing or sanding of drywall cement, and the cleanup of asbestos insulation or lagging materials. The available evidence suggests that although many historical measurements exceeded the current OSHA 8-h time-weighted average (TWA) permissible exposure limit (PEL) of 0.1 fibers/cc, average fiber concentrations generally did not exceed historical occupational exposure limits in place at the time, except perhaps during ripout activities or the spraying of asbestos in enclosed spaces or onboard ships. Additionally, reported fiber concentrations may not have represented daily or actual human exposures to asbestos, since few samples were collected beyond specific short-term tasks and workers sometimes wore respiratory protective equipment. The available data were not sufficient to determine whether the airborne fiber concentrations represented serpentine or amphibole asbestos fibers, which would have a pronounced impact on the potential health hazards posed by the asbestos. Despite a number of limitations associated with the available air sampling data, the information should provide guidance for reconstructing asbestos exposures for different crafts in specific occupational settings where asbestos was present during the 1940 to 2006 time period.

Special analysis of community annoyance with aircraft noise reported by residents in the vicinity of JFK Airport, 1972

NASA Technical Reports Server (NTRS)

Borsky, P. N.

1975-01-01

During the summer of 1972, about 1500 residents were interviewed twice in 11 communities near JFK airport. Detailed aircraft operations reports were also collected for this period, and an effort has been made to analyze recorded human response data in relation to a number of physical exposure parameters. A series of exposure indexes, based on an arithmetic integration of aircraft operations, were correlated with summated aircraft noise annoyance responses. None of these correlations were as good as the CNR index which assumes a logrithmetic integration of numbers of aircraft exposures and includes a day-night differential weighting of 10:1. There were substantial variations in average annoyance responses among communities with similar CNR exposures, substantiating previous findings that attitudinal and other personal variables also play an important role in determining annoyance differences.

Risk Factors for and Behavioral Consequences of Direct Versus Indirect Exposure to Violence

PubMed Central

Posick, Chad

2016-01-01

Research suggests that direct exposure (personal victimization) and indirect exposure (witnessing or hearing about the victimization of a family member, friend, or neighbor) to violence are correlated. However, questions remain about the co-occurrence of these phenomena within individuals. We used data on 1915 youths (with an average age of 12 years at baseline) from the Project on Human Development in Chicago Neighborhoods to examine this issue. Results indicated that youths who tended to be personally victimized were also likely to witness violence; conversely, youths who disproportionately witnessed violence were relatively unlikely to experience personal victimization. In addition, direct and indirect exposures to violence were associated with subsequent adverse outcomes in similar ways. The key distinguishing factor was, rather, the cumulative level of violence (both direct and indirect) to which youths were exposed. PMID:26562101

Uptake and disposition of 1,1-difluoroethane (HFC-152a) in humans.

PubMed

Ernstgård, Lena; Sjögren, Bengt; Dekant, Wolfgang; Schmidt, Tobias; Johanson, Gunnar

2012-02-25

The aim of this study was to determine the toxicokinetics of inhaled 1,1-difluoroethane (HFC-152a) in humans. Healthy volunteers were exposed to 0, 200 or 1000 ppm 1,1-difluoroethane for 2h at light exercise in an exposure chamber. Capillary blood, urine and exhaled air were sampled up to 22 h post-exposure and analyzed for 1,1-difluoroethane. Fluoride and other potential metabolites were analyzed in urine. Symptoms of irritation and central nervous system effects were rated and inflammatory markers were analyzed in blood. Within a few minutes of exposure to 200 and 1000 ppm, 1,1-difluoroethane increased rapidly in blood and reached average levels of 7.4 and 34.3 μM, respectively. The post-exposure decreases in blood were fast and parallel to those in exhaled air. The observed time courses in blood and breath agreed well with those obtained with the PBPK model. The PBPK simulations indicate a net uptake during exposure to 1000 ppm of 6.6 mmol (6.7%) which corresponds to the amount exhaled post-exposure. About 20 μmol excess fluoride (0.013% of inhaled 1,1-difluoroethane on a molar basis) was excreted in urine after exposure to 1000 ppm, compared to control. No fluorine-containing metabolites were detected in urine. Symptom ratings and changes in inflammatory markers revealed no exposure-related effects. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

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

PubMed

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

2014-07-01

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

Environmental effects and aquatic organisms: investigations of molecular mechanisms of carcinogenesis.

PubMed Central

Van Beneden, R J

1997-01-01

Cancers of the reproductive system are among the leading causes of mortality in women in the United States. While both genetic and environmental factors have been implicated in their etiology, the extent of the contribution of environmental factors to human diseases remains controversial. To better address the role of environmental exposures in cancer etiology, there has been an increasing focus on the development of nontraditional, environmentally relevant models. Our research involves the development of one such model. Gonadal tumors have been described in the softshell clam (Mya arenaria) in Maine and the hardshell clam (Mercenaria spp.) from Florida. Prevalence of these tumors is as high as 40% in some populations in eastern Maine and 60% in some areas along the Indian River in Florida. The average tumor prevalence in Maine and Florida is approximately 20 and 11%, respectively. An association has been suggested between the use of herbicides and the incidence of gonadal tumors in the softshell clam in Maine. The role of environmental exposures in the development of the tumors in Mercenaria in Florida is unknown; however, there is evidence that genetic factors may contribute to its etiology. Epidemiologic studies of human populations in these same areas show a higher than average mortality rate due to cancers of the reproductive system in women, including both ovarian and breast cancer. The relationship, if any, among these observations is unknown. Our studies on the molecular basis of this disease in clams may provide additional information on environmental exposures and their possible link to cancer in clams and other organisms, including humans. Images Figure 1. A Figure 1. B PMID:9168012

Mercury contamination in fish and human hair from Hainan Island, South China Sea: Implication for human exposure.

PubMed

Liu, Jin-Ling; Xu, Xiang-Rong; Yu, Shen; Cheng, Hefa; Peng, Jia-Xi; Hong, Yi-Guo; Feng, Xin-Bin

2014-11-01

Hair has long been recognized as a good biomarker for human exposure to Hg. The mercury concentrations in 14 species of marine fish and hair samples from 177 coastal residents in Hainan, South China Sea were investigated to assess the status of mercury exposure associated with marine fish consumption. Concentrations of total Hg (THg) and methylmercury (MeHg) in the fish muscles were 0.094 ± 0.008 and 0.066 ± 0.006 μg/gww, respectively, which were far below the limit considered safe for consumption (0.5 μg/g). The average THg concentrations in hair of adults (1.02 ± 0.92 μg/g) were lower than the provisional tolerable weekly intake (PTWI) level of 2.2 μg/g. However, 23.7% of children had a hair THg level exceeding the RfD level of 1μg/g, indicating a great risk of Hg exposure to children via fish consumption. The concentration of THg in hair was significantly correlated with fish consumption but not with gender-specific fish intake. With higher fish consumption frequency, the fishermen had significantly elevated hair Hg levels compared to the students and the other general public, who had similar hair THg levels but different fish consumption patterns, indicating the existence of other sources of Hg exposure to the residents of Hainan Island. Copyright © 2014 Elsevier Inc. All rights reserved.

Gas and aerosol carbon in California: comparison of ...

EPA Pesticide Factsheets

Co-located measurements of fine particulate matter (PM2.5) organic carbon (OC), elemental carbon, radiocarbon (14C), speciated volatile organic compounds (VOCs),and OH radicals during the CalNex field campaign provide a unique opportunity to evaluate the Community Multiscale Air Quality (CMAQ) model's representation of organic species from VOCs to particles. Episode average daily 23 h average 14C analysis indicates PM2.5 carbon at Pasadena and Bakersfield during the CalNex field campaign was evenly split between contemporary and fossil origins. CMAQ predicts a higher contemporary carbon fraction than indicated by the 14C analysis at both locations. The model underestimates measured PM2.5 organic carbon at both sites with very little (7% in Pasadena) of the modeled mass represented by secondary production, which contrasts with the ambient-based SOC/OC fraction of 63% at Pasadena. The National Exposure Research Laboratory’s (NERL’s) Human Exposure and Atmospheric Sciences Division (HEASD) conducts research in support of EPA’s mission to protect human health and the environment. HEASD’s research program supports Goal 1 (Clean Air) and Goal 4 (Healthy People) of EPA’s strategic plan. More specifically, our division conducts research to characterize the movement of pollutants from the source to contact with humans. Our multidisciplinary research program produces Methods, Measurements, and Models to identify relationships between and characterize processe

An assessment of sources and pathways of human exposure to polybrominated diphenyl ethers in the United States.

PubMed

Johnson-Restrepo, Boris; Kannan, Kurunthachalam

2009-07-01

Polybrominated diphenyl ethers (PBDEs) are ubiquitous in the indoor environment, owing to their use in consumer products ranging from electronics to mattresses, furniture, and carpets. People are exposed to PBDEs through inhalation of indoor air and ingestion, and dermal absorption of dust particles present in the air. In this study, concentrations of PBDEs were determined in indoor air and house dust collected from homes in Albany, New York, USA. Based on the measured concentrations of PBDEs in indoor air and dust, we estimated daily exposure dose (DED) of PBDEs. In addition, we used previously published PBDE concentrations reported for breast milk from Massachusetts, USA [Johnson-Restrepo, B., Addink, R., Wong, C., Arcaro, K., Kannan, K., 2007. Polybrominated diphenyl ethers and organochlorine pesticides in human breast milk from Massachusetts. USA. J. Environ. Monitor. 9, 1205-1212] and foodstuffs collected from Texas and Florida, USA [Schecter, A., Päpke, O., Harris, T.R., Tung, K.C., Musumba, A., Olson, J., Birnbaum, L., 2006. Polybrominated diphenyl ether (PBDE) levels in an expanded market basket survey of U.S. food and estimated PBDE dietary intake by age and sex. Environ. Health Perspect. 114, 1515-1520, Johnson-Restrepo, B., Kannan, K., Addink, R., Adams, D.H., 2005b. Polybrominated diphenyl ethers and polychlorinated biphenyls in a marine foodweb of coastal Florida. Environ. Sci. Technol. 39, 8243-8250], in an estimation of dietary exposure to PBDEs. The exposure assessment was performed for five age groups: infants (<1yr), toddlers (1-5yr), children (6-11yr), teenagers (12-19yr), and adults (20yr). The dust ingestion and air inhalation factors that we used were the US Environmental Protection Agency's (EPA) exposure factors, while the daily food intake rates (g/day) were derived from the US Department of Agriculture's (USDA) food intake surveys. The total DED of PBDEs was calculated by summation of the exposures from diet, indoor air, and house dust. The average estimated DED of PBDEs was the highest for breastfed infants (86.4ng/kg-bw/day), contributed primarily (91%) from the consumption of breast milk. The average DED of PBDEs for toddlers, children, teenagers, and adults was respectively, 13.3, 5.3, 3.5, and 2.9ng/kg-bw/day. Ingestion and dermal absorption of house dust are the major pathways of PBDE exposure in toddlers, children, teenagers, and adults accounting for, on average, 56-77% of the total PBDE intake.

Using air quality modeling to study source-receptor relationships between nitrogen oxides emissions and ozone exposures over the United States.

PubMed

Tong, Daniel Q; Muller, Nicholas Z; Kan, Haidong; Mendelsohn, Robert O

2009-11-01

Human exposure to ambient ozone (O(3)) has been linked to a variety of adverse health effects. The ozone level at a location is contributed by local production, regional transport, and background ozone. This study combines detailed emission inventory, air quality modeling, and census data to investigate the source-receptor relationships between nitrogen oxides (NO(x)) emissions and population exposure to ambient O(3) in 48 states over the continental United States. By removing NO(x) emissions from each state one at a time, we calculate the change in O(3) exposures by examining the difference between the base and the sensitivity simulations. Based on the 49 simulations, we construct state-level and census region-level source-receptor matrices describing the relationships among these states/regions. We find that, for 43 receptor states, cumulative NO(x) emissions from upwind states contribute more to O(3) exposures than the state's own emissions. In-state emissions are responsible for less than 15% of O(3) exposures in 90% of U.S. states. A state's NO(x) emissions can influence 2 to 40 downwind states by at least a 0.1 ppbv change in population-averaged O(3) exposure. The results suggest that the U.S. generally needs a regional strategy to effectively reduce O(3) exposures. But the current regional emission control program in the U.S. is a cap-and-trade program that assumes the marginal damage of every ton of NO(x) is equal. In this study, the average O(3) exposures caused by one ton of NO(x) emissions ranges from -2.0 to 2.3 ppm-people-hours depending on the state. The actual damage caused by one ton of NO(x) emissions varies considerably over space.

Scented traces--Dermal exposure of synthetic musk fragrances in personal care products and environmental input assessment.

PubMed

Homem, Vera; Silva, Eduardo; Alves, Arminda; Santos, Lúcia

2015-11-01

Synthetic musks are organic compounds used as fragrance and fixative additives in several personal care products. Until now, little is known about their occurrence and distribution in these household commodities. However, this information is essential to perform a human dermal exposure assessment. Therefore, this study gives an overview on the levels of 12 synthetic musks in 140 personal care products from 7 different categories (body and hair wash, toilet soaps, shaving products, dentifrice products, deodorants/antiperspirants, moisturizers and perfumes). They were analysed by QuEChERS extraction followed by gas chromatography-mass spectrometry. Detection limits were found between 0.01ngg(-1) (galaxolide) and 5.00ngg(-1) (musk xylene). Higher average concentrations of total synthetic musks were detected in perfumes (5245.05μgg(-1)) and shampoos (487.67μgg(-1)) for adults. Galaxolide, exaltolide and cashmeran were the most detected compounds. Combining these results with the daily usage amounts, an average daily dermal exposure of 75.69μgkgbw(-1)day(-1) for adults and 15.54μgkgbw(-1)day(-1) for babies/children was achieved. The main contributors for adult and babies/children dermal exposure were perfumes and lotions, respectively. About 40% of the adult daily dermal exposure is related to exaltolide, 30% galaxolide, and 15% tonalide, while for babies/children 96% occurs due to exaltolide. An estimate of the amount of musks discharged "down-the-drain" into the wastewater treatment systems through the use of toiletries was also performed. An average emission per capita of 6.7mgday(-1) was determined and galaxolide and exaltolide were the predominant musks in the effluents. Copyright © 2015 Elsevier Ltd. All rights reserved.

Excretion Profiles and Half-Lives of Ten Urinary Polycyclic Aromatic Hydrocarbon Metabolites after Dietary Exposure

PubMed Central

Li, Zheng; Romanoff, Lovisa; Bartell, Scott; Pittman, Erin N.; Trinidad, Debra A.; McClean, Michael; Webster, Thomas F.; Sjödin, Andreas

2015-01-01

Human exposure to polycyclic aromatic hydrocarbons (PAHs) can be assessed by biomonitoring of their urinary mono-hydroxylated metabolites (OH-PAHs). Limited information exists on the human pharmacokinetics of OH-PAHs. This study aimed to investigate the excretion half-life of 1-hydroxypyrene (1-PYR), the most used biomarker for PAH exposure, and 9 other OH-PAHs following a dietary exposure in 9 non-smoking volunteers with no occupational exposure to PAHs. Each person avoided food with known high PAH-content during the study period, except for a high PAH-containing lunch (barbecued chicken) on the first day. Individual urine samples (n = 217) were collected from 15 hours before to 60 hours following the dietary exposure. Levels of all OH-PAHs in all subjects increased rapidly by 9–141 fold after the exposure, followed by a decrease consistent with first order kinetics, and returned to background levels 24–48 hours after the exposure. The average time to reach maximal concentration ranged from 3.1 h (1-naphthol) to 5.5 h (1-PYR). Creatinine-adjusted urine concentrations for each metabolite were analyzed using a non-linear mixed effects model including a term to estimate background exposure. The background-adjusted half-life estimate was 3.9 h for 1-PYR and ranged 2.5–6.1 h for the other 9 OH-PAHs, which in general, were shorter than those previously reported. The maximum concentrations after the barbecued chicken consumption were comparable to the levels found in reported occupational settings with known high PAH exposures. It is essential to consider the relatively short half-life, the timing of samples relative to exposures, and the effect of diet when conducting PAH exposure biomonitoring studies. PMID:22663094

Ozone killing action against bacterial and fungal species; microbiological testing of a domestic ozone generator.

PubMed

Dyas, A; Boughton, B J; Das, B C

1983-10-01

The action of ozone generated from a small domestic device was examined with a view to using it in clinical isolation units accommodating immunosuppressed patients. Over a six-hour period in an average size room the device did not generate sufficient ozone to suppress bacterial and fungal growth. A useful bactericidal action, against a variety of human pathogens was achieved with ozone concentrations between 0.3 to 0.9 ppm. Bactericidal ozone concentrations are close to the limit permitted for human exposure however and further experiments are indicated.

Comparison of Highly Resolved Model-Based Exposure ...

EPA Pesticide Factsheets

Human exposure to air pollution in many studies is represented by ambient concentrations from space-time kriging of observed values. Space-time kriging techniques based on a limited number of ambient monitors may fail to capture the concentration from local sources. Further, because people spend more time indoors, using ambient concentration to represent exposure may cause error. To quantify the associated exposure error, we computed a series of six different hourly-based exposure metrics at 16,095 Census blocks of three Counties in North Carolina for CO, NOx, PM2.5, and elemental carbon (EC) during 2012. These metrics include ambient background concentration from space-time ordinary kriging (STOK), ambient on-road concentration from the Research LINE source dispersion model (R-LINE), a hybrid concentration combining STOK and R-LINE, and their associated indoor concentrations from an indoor infiltration mass balance model. Using a hybrid-based indoor concentration as the standard, the comparison showed that outdoor STOK metrics yielded large error at both population (67% to 93%) and individual level (average bias between −10% to 95%). For pollutants with significant contribution from on-road emission (EC and NOx), the on-road based indoor metric performs the best at the population level (error less than 52%). At the individual level, however, the STOK-based indoor concentration performs the best (average bias below 30%). For PM2.5, due to the relatively low co

Computational modeling of temperature elevation and thermoregulatory response in the brains of anesthetized rats locally exposed at 1.5 GHz

NASA Astrophysics Data System (ADS)

Hirata, Akimasa; Masuda, Hiroshi; Kanai, Yuya; Asai, Ryuichi; Fujiwara, Osamu; Arima, Takuji; Kawai, Hiroki; Watanabe, Soichi; Lagroye, Isabelle; Veyret, Bernard

2011-12-01

The dominant effect of human exposures to microwaves is caused by temperature elevation ('thermal effect'). In the safety guidelines/standards, the specific absorption rate averaged over a specific volume is used as a metric for human protection from localized exposure. Further investigation on the use of this metric is required, especially in terms of thermophysiology. The World Health Organization (2006 RF research agenda) has given high priority to research into the extent and consequences of microwave-induced temperature elevation in children. In this study, an electromagnetic-thermal computational code was developed to model electromagnetic power absorption and resulting temperature elevation leading to changes in active blood flow in response to localized 1.457 GHz exposure in rat heads. Both juvenile (4 week old) and young adult (8 week old) rats were considered. The computational code was validated against measurements for 4 and 8 week old rats. Our computational results suggest that the blood flow rate depends on both brain and core temperature elevations. No significant difference was observed between thermophysiological responses in 4 and 8 week old rats under these exposure conditions. The computational model developed herein is thus applicable to set exposure conditions for rats in laboratory investigations, as well as in planning treatment protocols in the thermal therapy.

Comparison of self-reported and observed water contact in an S. mansoni endemic village in Brazil.

PubMed

Friedman, J F; Kurtis, J D; McGarvey, S T; Fraga, A L; Silveira, A; Pizziolo, V; Gazzinelli, G; LoVerde, P; Corrêa-Oliveira, R

2001-03-30

Estimates of exposure are critical for immuno-epidemiologic and intervention studies in human schistosomiasis. Direct observation of human water contact patterns is both costly and time consuming. To address these issues, we determined whether individuals residing in a Schistosoma mansoni endemic village in Brazil could accurately self-report their water contact patterns. We compared the results of a water contact questionnaire to the present gold standard, direct observation of water contact in 86 volunteers, aged 8--29. We administered a survey to estimate volunteers' frequency and type of water contact and directly measured each volunteers' water contact patterns during 5 weeks of detailed water contact observations. We found a poor correlation between self reported frequency of contact and directly observed exposure (rho=0.119, P=NS). The questionnaire data was supplemented by information about average body surface area of exposure and duration of contact for specific activities derived from observations of this cohort. This 'supplemented questionnaire' data was significantly correlated with their exposure index (rho=0.227, P=0.05). It provides a starting point from which questionnaires may develop to provide a more cost-effective and less labor intensive method of assessing water contact exposure at the level of the individual.

Per- and polyfluorinated compounds (PFCs) in house dust and indoor air in Catalonia, Spain: implications for human exposure.

PubMed

Ericson Jogsten, I; Nadal, M; van Bavel, B; Lindström, G; Domingo, J L

2012-02-01

A total of 27 per- and polyfluorinated compounds (PFCs) were determined in both house dust (n=10) and indoor air (n=10) from selected homes in Catalonia, Spain. Concentrations were found to be similar or lower than those previously reported for household microenvironments in other countries. Ten PFCs were detected in all house dust samples. The highest mean concentrations corresponded to perfluorodecanoic acid (PFDA) and perfluorononanoic acid (PFNA), 10.7 ng/g (median: 1.5 ng/g) and 10.4 ng/g (median: 5.4 ng/g), respectively, while the 8:2 fluorotelomer alcohol (FTOH) was the dominating neutral PFC at a concentration of 0.41 ng/g (median: 0.35 ng/g). The indoor air was dominated by the FTOHs, especially the 8:2 FTOH at a mean (median) concentration of 51 pg/m(3) (median: 42 pg/m(3)). A limited number of ionic PFCs were also detected in the indoor air samples. Daily intakes of PFCs were estimated for average and worst case scenarios of human exposure from indoor sources. For toddlers, this resulted in average intakes of ∑ionic PFCs of 4.9ng/day (0.33 ng/kg(bw)/day for a 15 kg toddlers) and ∑neutral PFCs of 0.072 ng/day (0.005 ng/kg(bw)/day) from house dust. For adults, the average daily intakes of dust were 3.6 and 0.053 ng/day (0.05 and 0.001 ng/kg(bw)/day for a 70 kg adult) for ∑ionic and ∑neutral PFCs, respectively. The average daily inhalation of ∑neutral PFCs was estimated to be 0.9 and 1.3 ng/day (0.06 and 0.02 ng/kg(bw)/day) for toddlers and adults, respectively. For PFOS, the main ionic PFC detected in indoor air samples, the median intakes (based on those samples where PFOS was detected), resulted in indoor exposures of 0.06 and 0.11 ng/day (0.004 and 0.002 ng/kg(bw)/day) for toddlers and adults, respectively. Based on previous studies on dietary intake and drinking water consumption, both house dust and indoor air contribute significantly less to PFC exposure within this population. Copyright © 2011 Elsevier Ltd. All rights reserved.

The potential impacts of 21st century climatic and population changes on human exposure to the virus vector mosquito Aedes aegypti.

PubMed

Monaghan, A J; Sampson, K M; Steinhoff, D F; Ernst, K C; Ebi, K L; Jones, B; Hayden, M H

2018-02-01

The mosquito Aedes (Ae). aegypti transmits the viruses that cause dengue and chikungunya, two globally-important vector-borne diseases. We investigate how choosing alternate emissions and/or socioeconomic pathways may modulate future human exposure to Ae. aegypti . Occurrence patterns for Ae. aegypti for 2061-2080 are mapped globally using empirically downscaled air temperature and precipitation projections from the Community Earth System Model, for the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. Population growth is quantified using gridded global population projections consistent with two Shared Socioeconomic Pathways (SSPs), SSP3 and SSP5. Change scenarios are compared to a 1950-2000 reference period. A global land area of 56.9 M km 2 is climatically suitable for Ae. aegypti during the reference period, and is projected to increase by 8% (RCP4.5) to 13% (RCP8.5) by 2061-2080. The annual average number of people exposed globally to Ae. aegypti for the reference period is 3794 M, a value projected to statistically significantly increase by 298-460 M (8-12%) by 2061-2080 if only climate change is considered, and by 4805-5084 M (127-134%) for SSP3 and 2232-2483 M (59-65%) for SSP5 considering both climate and population change (lower and upper values of each range represent RCP4.5 and RCP8.5 respectively). Thus, taking the lower-emissions RCP4.5 pathway instead of RCP8.5 may mitigate future human exposure to Ae. aegypti globally, but the effect of population growth on exposure will likely be larger. Regionally, Australia, Europe and North America are projected to have the largest percentage increases in human exposure to Ae. aegypti considering only climate change.

Measurement of airborne concentrations of tire and road wear particles in urban and rural areas of France, Japan, and the United States

NASA Astrophysics Data System (ADS)

Panko, Julie M.; Chu, Jennifer; Kreider, Marisa L.; Unice, Ken M.

2013-06-01

In addition to industrial facilities, fuel combustion, forest fires and dust erosion, exhaust and non-exhaust vehicle emissions are an important source of ambient air respirable particulate matter (PM10). Non-exhaust vehicle emissions are formed from wear particles of vehicle components such as brakes, clutches, chassis and tires. Although the non-exhaust particles are relatively minor contributors to the overall ambient air particulate load, reliable exposure estimates are few. In this study, a global sampling program was conducted to quantify tire and road wear particles (TRWP) in the ambient air in order to understand potential human exposures and the overall contribution of these particles to the PM10. The sampling was conducted in Europe, the United States and Japan and the sampling locations were selected to represent a variety of settings including both rural and urban core; and within each residential, commercial and recreational receptors. The air samples were analyzed using validated chemical markers for rubber polymer based on a pyrolysis technique. Results indicated that TRWP concentrations in the PM10 fraction were low with averages ranging from 0.05 to 0.70 μg m-3, representing an average PM10 contribution of 0.84%. The TRWP concentration in air was associated with traffic load and population density, but the trend was not statistically significant. Further, significant differences across days were not observed. This study provides a robust dataset to understand potential human exposures to airborne TRWP.

Exposure to Carbon Ions Triggers Proinflammatory Signals and Changes in Homeostasis and Epidermal Tissue Organization to a Similar Extent as Photons

PubMed Central

Simoniello, Palma; Wiedemann, Julia; Zink, Joana; Thoennes, Eva; Stange, Maike; Layer, Paul G.; Kovacs, Maximilian; Podda, Maurizio; Durante, Marco; Fournier, Claudia

2016-01-01

The increasing application of charged particles in radiotherapy requires a deeper understanding of early and late side effects occurring in skin, which is exposed in all radiation treatments. We measured cellular and molecular changes related to the early inflammatory response of human skin irradiated with carbon ions, in particular cell death induction and changes in differentiation and proliferation of epidermal cells during the first days after exposure. Model systems for human skin from healthy donors of different complexity, i.e., keratinocytes, coculture of skin cells, 3D skin equivalents, and skin explants, were used to investigate the alterations induced by carbon ions (spread-out Bragg peak, dose-averaged LET 100 keV/μm) in comparison to X-ray and UV-B exposure. After exposure to ionizing radiation, in none of the model systems, apoptosis/necrosis was observed. Carbon ions triggered inflammatory signaling and accelerated differentiation of keratinocytes to a similar extent as X-rays at the same doses. High doses of carbon ions were more effective than X-rays in reducing proliferation and inducing abnormal differentiation. In contrast, changes identified following low-dose exposure (≤0.5 Gy) were induced more effectively after X-ray exposure, i.e., enhanced proliferation and change in the polarity of basal cells. PMID:26779439

Assessment of Population and Microenvironmental Exposure to Fine Particulate Matter (PM2.5)

NASA Astrophysics Data System (ADS)

Jiao, Wan

A positive relationship exists between fine particulate matter (PM 2.5) exposure and adverse health effects. PM2.5 concentration-response functions used in the quantitative risk assessment were based on findings from human epidemiological studies that relied on areawide ambient concentrations as surrogate for actual ambient exposure, which cannot capture the spatial and temporal variability in human exposures. The goal of the study is to assess inter-individual, geographic and seasonal variability in population exposures to inform the interpretation of available epidemiological studies, and to improve the understanding of how exposure-related factors in important exposure microenvironments contribute to the variability in individual PM2.5 exposure. Typically, the largest percentage of time in which an individual is exposed to PM2.5 of ambient origin occurs in indoor residence, and the highest ambient PM2.5 concentrations occur in transportation microenvironments because of the proximity to on-road traffic emissions. Therefore, indoor residence and traffic-related transportation microenvironments were selected for further assessment in the study. Population distributions of individual daily PM2.5 exposures were estimated for the selected regions and seasons using the Stochastic Human Exposure and Dose Simulation Model for Particulate Matter (SHEDS-PM). For the indoor residence, the current practice by assuming the entire residence to be one large single zone for calculating the indoor residential PM 2.5 concentration was evaluated by applying an indoor air quality model, RISK, to compare indoor PM2.5 concentrations between single-zone and multi-zone scenarios. For the transportation microenvironments, one field data collection focused on in-vehicle microenvironment and was conducted to quantify the variability in the in-vehicle PM2.5 concentration with respect to the outside vehicle concentration for a wide range of conditions that affect intra-vehicle variability in exposure concentration, including ventilation air source, window status, fan setting, AC utilization, vehicle speed, road type, travel direction, and time of day. Another field data collection measured PM2.5 exposure concentrations on pre-selected routes across transportation modes of pedestrian, bus, and car to quantify the variability in the transportation mode concentration ratios, and identify factors affecting variability in traffic-related concentrations. In general, population daily average exposure to ambient PM2.5 is less than the ambient concentration by approximately half. The ratio of PM2.5 ambient exposure to ambient concentration (Ea/C) varies by individual, geographic area and season, as a result of regional differences in housing stock and seasonal differences in air exchange rates (ACH). For the indoor residence, the single-zone assumption is biased when any non-ambient source is presented. Bias correction factors are developed for cooking and smoking scenarios, separately, to improve the concentration estimates. Correction factors are most sensitive to changes in ACH but relatively insensitive to variations in source emission rate and duration. In a SHEDS-PM case study, the population daily average total exposure increased by 17% after applying correction factors. Transportation mode exposure concentrations are sensitive to mode, and are affected by factors such as vehicle ventilation and proximity to on-road emission sources. The in-vehicle to outside vehicle concentration (I/O) ratio is highly sensitive to whether windows are open or, for closed windows, to whether fresh air or recirculating air is used. Both model simulations and field studies are needed to inform better understanding of human exposure. Exposure, and not just concentration, should be considered in developing risk management strategies to reduce uncertainty in health effect estimates, and to identify highly exposed groups and possible exposure reduction strategies.

System for ranking relative threats of U.S. volcanoes

USGS Publications Warehouse

Ewert, J.W.

2007-01-01

A methodology to systematically rank volcanic threat was developed as the basis for prioritizing volcanoes for long-term hazards evaluations, monitoring, and mitigation activities. A ranking of 169 volcanoes in the United States and the Commonwealth of the Northern Mariana Islands (U.S. volcanoes) is presented based on scores assigned for various hazard and exposure factors. Fifteen factors define the hazard: Volcano type, maximum known eruptive explosivity, magnitude of recent explosivity within the past 500 and 5,000 years, average eruption-recurrence interval, presence or potential for a suite of hazardous phenomena (pyroclastic flows, lahars, lava flows, tsunami, flank collapse, hydrothermal explosion, primary lahar), and deformation, seismic, or degassing unrest. Nine factors define exposure: a measure of ground-based human population in hazard zones, past fatalities and evacuations, a measure of airport exposure, a measure of human population on aircraft, the presence of power, transportation, and developed infrastructure, and whether or not the volcano forms a significant part of a populated island. The hazard score and exposure score for each volcano are multiplied to give its overall threat score. Once scored, the ordered list of volcanoes is divided into five overall threat categories from very high to very low. ?? 2007 ASCE.

Screening-Level Risk Assessment for Styrene-Acrylonitrile (SAN) Trimer Detected in Soil and Groundwater

PubMed Central

Kirman, C. R.; Gargas, M. L.; Collins, J. J.; Rowlands, J. C.

2012-01-01

A screening-level risk assessment was conducted for styrene-acrylonitrile (SAN) Trimer detected at the Reich Farm Superfund site in Toms River, NJ. Consistent with a screening-level approach, on-site and off-site exposure scenarios were evaluated using assumptions that are expected to overestimate actual exposures and hazards at the site. Environmental sampling data collected for soil and groundwater were used to estimate exposure point concentrations. Several exposure scenarios were evaluated to assess potential on-site and off-site exposures, using parameter values for exposures to soil (oral, inhalation of particulates, and dermal contact) and groundwater (oral, dermal contact) to reflect central tendency exposure (CTE) and reasonable maximum exposure (RME) conditions. Three reference dose (RfD) values were derived for SAN Trimer for short-term, subchronic, and chronic exposures, based upon its effects on the liver in exposed rats. Benchmark (BMD) methods were used to assess the relationship between exposure and response, and to characterize appropriate points of departure (POD) for each RfD. An uncertainty factor of 300 was applied to each POD to yield RfD values of 0.1, 0.04, and 0.03 mg/kg-d for short-term, subchronic, and chronic exposures, respectively. Because a chronic cancer bioassay for SAN Trimer in rats (NTP 2011a) does not provide evidence of carcinogenicity, a cancer risk assessment is not appropriate for this chemical. Potential health hazards to human health were assessed using a hazard index (HI) approach, which considers the ratio of exposure dose (i.e., average daily dose, mg/kg-d) to toxicity dose (RfD, mg/kg-d) for each scenario. All CTE and RME HI values are well below 1 (where the average daily dose is equivalent to the RfD), indicating that there is no concern for potential noncancer effects in exposed populations even under the conservative assumptions of this screening-level assessment. PMID:23030654

Calculating Solar Ultraviolet Irradiation Of The Human Cornea And Corresponding Required Sunglass Lens Transmittances

NASA Astrophysics Data System (ADS)

Hoover, Herbert L.; Marsaud, Serge G.

1986-05-01

Tinted ophthalmic lenses are used primarily for eye comfort in a brightly lit environment. An ancillary benefit is the attenuation of ultraviolet radiation. Some national product standards specify quantitative limits for ultraviolet transmittances. Such limits ought to be founded on quantitative estimates of solar irradiances of ocular tissues, with actinic effectiveness taken into account. We use the equations of Green and coworkers for direct and diffuse solar irradiance at the earth's surface to calculate average sky and ground spectral radiances. We use the geometric factors derived by us for the coupling of radiation from these sources to the human cornea. Actinically weighted corneal spectral irradiances integrated over wavelength and time yield peak irradiances and accumulated exposure doses that are compared with recommended exposure limits. This provides the maximal effective ultraviolet transmittances of tinted ophthalmic lenses such that these exposure limits will not be exceeded in the selected exposure environment. The influences on corneal irradiation of such exposure parameters as solar zenith angle, altitude of the exposure site, characteristics of atmospheric aerosols, and ground reflectances are illustrated. The relationships between the effective transmittance (which is a function of the environmental radiation and any actinicweighting function) and readily determined characteristics of the lens itself, viz., its mean transmittance, and a selected spectral transmittance, are derived for three lens transmittance curves. Limits of lens transmittance for the UV-B and UV-A wavelength regions are presented for several representative exposure sites in Europe and the U.S.A.

Using a chemistry transport model to account for the spatial variability of exposure concentrations in epidemiologic air pollution studies.

PubMed

Valari, Myrto; Menut, Laurent; Chatignoux, Edouard

2011-02-01

Environmental epidemiology and more specifically time-series analysis have traditionally used area-averaged pollutant concentrations measured at central monitors as exposure surrogates to associate health outcomes with air pollution. However, spatial aggregation has been shown to contribute to the overall bias in the estimation of the exposure-response functions. This paper presents the benefit of adding features of the spatial variability of exposure by using concentration fields modeled with a chemistry transport model instead of monitor data and accounting for human activity patterns. On the basis of county-level census data for the city of Paris, France, and a Monte Carlo simulation, a simple activity model was developed accounting for the temporal variability between working and evening hours as well as during transit. By combining activity data with modeled concentrations, the downtown, suburban, and rural spatial patterns in exposure to nitrogen dioxide, ozone, and PM2.5 (particulate matter [PM] < or = 10 microm in aerodynamic diameter) were captured and parametrized. Exposures predicted with this model were used in a time-series study of the short-term effect of air pollution on total nonaccidental mortality for the 4-yr period from 2001 to 2004. It was shown that the time series of the exposure surrogates developed here are less correlated across co-pollutants than in the case of the area-averaged monitor data. This led to less biased exposure-response functions when all three co-pollutants were inserted simultaneously in the same regression model. This finding yields insight into pollutant-specific health effects that are otherwise masked by the high correlation among co-pollutants.

Assessment of potential effects of the electromagnetic fields of mobile phones on hearing

PubMed Central

Uloziene, Ingrida; Uloza, Virgilijus; Gradauskiene, Egle; Saferis, Viktoras

2005-01-01

Background Mobile phones have become indispensable as communication tools; however, to date there is only a limited knowledge about interaction between electromagnetic fields (EMF) emitted by mobile phones and auditory function. The aim of the study was to assess potential changes in hearing function as a consequence of exposure to low-intensity EMF's produced by mobile phones at frequencies of 900 and 1800 MHz. Methods The within-subject study was performed on thirty volunteers (age 18–30 years) with normal hearing to assess possible acute effect of EMF. Participants attended two sessions: genuine and sham exposure of EMF. Hearing threshold levels (HTL) on pure tone audiometry (PTA) and transient evoked otoacoustic emissions (TEOAE's) were recorded before and immediately after 10 min of genuine and/or sham exposure of mobile phone EMF. The administration of genuine or sham exposure was double blind and counterbalanced in order. Results Statistical analysis revealed no significant differences in the mean HTLs of PTA and mean shifts of TEOAE's before and after genuine and/or sham mobile phone EMF 10 min exposure. The data collected showed that average TEOAE levels (averaged across a frequency range) changed less than 2.5 dB between pre- and post-, genuine and sham exposure. The greatest individual change was 10 dB, with a decrease in level from pre- to post- real exposure. Conclusion It could be concluded that a 10-min close exposure of EMFs emitted from a mobile phone had no immediate after-effect on measurements of HTL of PTA and TEOAEs in young human subjects and no measurable hearing deterioration was detected in our study. PMID:15840162

Occurrence of aflatoxin M1 in human milk samples in Vojvodina, Serbia: Estimation of average daily intake by babies.

PubMed

Radonić, Jelena R; Kocić Tanackov, Sunčica D; Mihajlović, Ivana J; Grujić, Zorica S; Vojinović Miloradov, Mirjana B; Škrinjar, Marija M; Turk Sekulić, Maja M

2017-01-02

The objectives of the study were to determine the aflatoxin M1 content in human milk samples in Vojvodina, Serbia, and to assess the risk of infants' exposure to aflatoxins food contamination. The growth of Aspergillus flavus and production of aflatoxin B1 in corn samples resulted in higher concentrations of AFM1 in milk and dairy products in 2013, indicating higher concentrations of AFM1 in human milk samples in 2013 and 2014 in Serbia. A total number of 60 samples of human milk (colostrum and breast milk collected 4-8 months after delivery) were analyzed for the presence of AFM1 using the Enzyme Linked Immunosorbent Assay method. The estimated daily intake of AFM1 through breastfeeding was calculated for the colostrum samples using an average intake of 60 mL/kg body weight (b.w.)/day on the third day of lactation. All breast milk collected 4-8 months after delivery and 36.4% of colostrum samples were contaminated with AFM1. The greatest percentage of contaminated colostrum (85%) and all samples of breast milk collected 4-8 months after delivery had AFM1 concentration above maximum allowable concentration according to the Regulation on health safety of dietetic products. The mean daily intake of AFM1 in colostrum was 2.65 ng/kg bw/day. Results of our study indicate the high risk of infants' exposure, who are at the early stage of development and vulnerable to toxic contaminants.

Analysis of impact noise induced by hitting of titanium head golf driver.

PubMed

Kim, Young Ho; Kim, Young Chul; Lee, Jun Hee; An, Yong-Hwi; Park, Kyung Tae; Kang, Kyung Min; Kang, Yeon June

2014-11-01

The hitting of titanium head golf driver against golf ball creates a short duration, high frequency impact noise. We analyzed the spectra of these impact noises and evaluated the auditory hazards from exposure to the noises. Noises made by 10 titanium head golf drivers with five maximum hits were collected, and the spectra of the pure impact sounds were studied using a noise analysis program. The noise was measured at 1.7 m (position A) and 3.4 m (position B) from the hitting point in front of the hitter and at 3.4 m (position C) behind the hitting point. Average time duration was measured and auditory risk units (ARUs) at position A were calculated using the Auditory Hazard Assessment Algorithm for Humans. The average peak levels at position A were 119.9 dBA at the sound pressure level (SPL) peak and 100.0 dBA at the overall octave level. The average peak levels (SPL and overall octave level) at position B were 111.6 and 96.5 dBA, respectively, and at position C were 111.5 and 96.7 dBA, respectively. The average time duration and ARUs measured at position A were 120.6 ms and 194.9 units, respectively. Although impact noises made by titanium head golf drivers showed relatively low ARUs, individuals enjoying golf frequently may be susceptible to hearing loss due to the repeated exposure of this intense impact noise with short duration and high frequency. Unprotected exposure to impact noises should be limited to prevent cochleovestibular disorders.

Wind-induced contaminant transport in near-surface soils with application to radon entry into buildings

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

Riley, William Jowett

1996-05-01

Indoor air exposures to gaseous contaminants originating in soil can cause large human health risks. To predict and control these exposures, the mechanisms that affect vapor transport in near-surface soils need to be understood. In particular, radon exposure is a concern since average indoor radon concentrations lead to much higher risks than are generally accepted for exposure to other environmental contaminants. This dissertation examines an important component of the indoor radon problem: the impacts of wind on soil-gas and radon transport and entry into buildings. The research includes experimental and modeling studies of wind`s interactions with a building`s superstructure andmore » the resulting soil-gas and radon flows in the surrounding soil. In addition to exploring the effects of steady winds, a novel modeling technique is developed to examine the impacts of fluctuating winds on soil-gas and radon transport.« less

The efficacy of ultrasound treatment as a reversible male contraceptive in the rhesus monkey.

PubMed

VandeVoort, Catherine A; Tollner, Theodore L

2012-09-12

The use of therapeutic ultrasound as a contraceptive approach has involved nonhuman primates as well as rats and dogs. The current study was undertaken to determine whether this treatment could be a method for reversible contraception, using a model with testes size similar to adult humans. Two methods of ultrasound exposure were used, either the transducer probe at the bottom of a cup filled with saline (Cup) or direct application to the surface of the scrotum (Direct). Four adult rhesus (Macaca mulatta) males with normal semen parameters were treated with therapeutic ultrasound at 2.5 W/cm(2) for 30 min. Treatment was given 3 times, one every other day on a Monday-Wednesday-Friday schedule. For each male, semen quality was evaluated a minimum of three times over several months prior to ultrasound exposure and weekly for two months following ultrasound treatment. Semen samples from all males, regardless of exposure method, exhibited a decrease in the percentage of motile sperm following ultrasound treatment. There was an average reduction in motility of 40% the week following treatment. Similarly, curvilinear velocity and the percentage of sperm with a normally shaped flagellum were also reduced in all males following ultrasound treatment. A significant reduction in the total number of sperm in an ejaculate (total sperm count) was only observed in males that received ultrasound via the cup method. Following treatment via the cup method, males exhibited up to a 91.7% decrease in average total sperm count (n = 2). Sperm count did not approach pre-treatment levels until 8 weeks following ultrasound exposure. The sustained reduction in sperm count, percent motility, normal morphology, and sperm vigor with the cup exposure method provides proof of principle that testicular treatment with ultrasound can be an effective contraceptive approach in humans.

Content of Heavy Metal in the Dust of Leisure Squares and Its Health Risk Assessment-A Case Study of Yanta District in Xi'an.

PubMed

Shao, Tianjie; Pan, Lihuan; Chen, Zhiqing; Wang, Ruiyuan; Li, Wenjing; Qin, Qing; He, Yuran

2018-02-25

Taking Yanta District in Xi'an as the research object, the present study measures the contents of Cadmium (Cd), Lead (Pb), Copper (Cu), Nickel (Ni), and Chromium (Cr) in dust samples and further assesses the health risk of heavy metals intake through dust based on the assessment method of human exposure risk proposed by U.S. EPA, with an aim to investigate the content of heavy metal in the dust of leisure squares and its exposure risk. As the results indicate, the average contents of five heavy metals are obviously higher than the soil background value in Shaanxi Province. Therefore, Cd, Ni, Cu, Pb, and Cr are obviously enriched in urban surface dust in Shaanxi Province, due to the influence of human activities. In addition, it can also be found that the non-carcinogen exposure risk in children is significantly higher than that in adults with the risk values of these five heavy metals all one order of magnitude higher than those of adults. Irrespective of whether addressing the results for children or adults, the non-carcinogen exposure doses of five heavy metals are sorted as Cr > Pb > Cu > Ni > Cd. According to the present situation, for a child, the total non-carcinogenic risk values of five heavy metals have exceeded the safety limit in 11 of the 20 leisure squares in Yanta District of Xi'an. That means the leisure squares are no longer suitable for physical and recreational activities. For the five heavy metals, the average non-carcinogenic risk value of Cr is largest, and causes the largest threat to health in Yanta District, Xi'an. The carcinogenic exposure doses of the heavy metals Cr, Cd, and Ni are very low in respiratory pathways and there is no carcinogenic health risk. In general, the Cr content in dust in domestic cities is higher than that of foreign cities; however, the Pb content is much lower.

Human Lung Cancer Risks from Radon – Part II – Influence from Combined Adaptive Response and Bystander Effects – A Microdose Analysis

PubMed Central

Leonard, Bobby E.; Thompson, Richard E.; Beecher, Georgia C.

2010-01-01

In the prior Part I, the potential influence of the low level alpha radiation induced bystander effect (BE) on human lung cancer risks was examined. Recent analysis of adaptive response (AR) research results with a Microdose Model has shown that single low LET radiation induced charged particles traversals through the cell nucleus activates AR. We have here conducted an analysis based on what is presently known about adaptive response and the bystander effect (BE) and what new research is needed that can assist in the further evaluation human cancer risks from radon. We find that, at the UNSCEAR (2000) worldwide average human exposures from natural background and man-made radiations, the human lung receives about a 25% adaptive response protection against the radon alpha bystander damage. At the UNSCEAR (2000) minimum range of background exposure levels, the lung receives minimal AR protection but at higher background levels, in the high UNSCEAR (2000) range, the lung receives essentially 100% protection from both the radon alpha damage and also the endogenic, spontaneously occurring, potentially carcinogenic, lung cellular damage. PMID:22461760

A combined experimental and numerical study on upper airway dosimetry of inhaled nanoparticles from an electrical discharge machine shop.

PubMed

Tian, Lin; Shang, Yidan; Chen, Rui; Bai, Ru; Chen, Chunying; Inthavong, Kiao; Tu, Jiyuan

2017-07-12

Exposure to nanoparticles in the workplace is a health concern to occupational workers with increased risk of developing respiratory, cardiovascular, and neurological disorders. Based on animal inhalation study and human lung tumor risk extrapolation, current authoritative recommendations on exposure limits are either on total mass or number concentrations. Effects of particle size distribution and the implication to regional airway dosages are not elaborated. Real time production of particle concentration and size distribution in the range from 5.52 to 98.2 nm were recorded in a wire-cut electrical discharge machine shop (WEDM) during a typical working day. Under the realistic exposure condition, human inhalation simulations were performed in a physiologically realistic nasal and upper airway replica. The combined experimental and numerical study is the first to establish a realistic exposure condition, and under which, detailed dose metric studies can be performed. In addition to mass concentration guided exposure limit, inhalation risks to nano-pollutant were reexamined accounting for the actual particle size distribution and deposition statistics. Detailed dosimetries of the inhaled nano-pollutants in human nasal and upper airways with respect to particle number, mass and surface area were discussed, and empirical equations were developed. An astonishing enhancement of human airway dosages were detected by current combined experimental and numerical study in the WEDM machine shop. Up to 33 folds in mass, 27 folds in surface area and 8 folds in number dosages were detected during working hours in comparison to the background dosimetry measured at midnight. The real time particle concentration measurement showed substantial emission of nano-pollutants by WEDM machining activity, and the combined experimental and numerical study provided extraordinary details on human inhalation dosimetry. It was found out that human inhalation dosimetry was extremely sensitive to real time particle concentration and size distribution. Averaged particle concentration over 24-h period will inevitably misrepresent the sensible information critical for realistic inhalation risk assessment. Particle size distribution carries very important information in determining human airway dosimetry. A pure number or mass concentration recommendation on the exposure limit at workplace is insufficient. A particle size distribution, together with the deposition equations, is critical to recognize the actual exposure risks. In addition, human airway dosimetry in number, mass and surface area varies significantly. A complete inhalation risk assessment requires the knowledge of toxicity mechanisms in response to each individual metric. Further improvements in these areas are needed.

Investigating the American Time Use Survey from an exposure modeling perspective.

PubMed

George, Barbara Jane; McCurdy, Thomas

2011-01-01

This paper describes an evaluation of the US Bureau of Labor Statistics' American Time Use Survey (ATUS) for potential use in modeling human exposures to environmental pollutants. The ATUS is a large, on-going, cross-sectional survey of where Americans spend time and what activities they undertake in those locations. The data are reported as a series of sequential activities over a 24-h time period--a "diary day"--starting at 0400 hours. Between 12,000 and 13,000 surveys are obtained each year and the Bureau has plans to continue ATUS for the foreseeable future. The ATUS already has about 73,000 diary days of data, more than twice as many as that which currently exists in the US Environmental Protection Agency's (EPA) "Consolidated Human Activity Database" (CHAD) that the Agency uses for exposure modeling purposes. There are limitations for using ATUS in modeling human exposures to environmental pollutants. The ATUS does not report the location for a number of activities regarded as "personal." For 2006, personal activities with missing location information totaled 572 min/day, on average, for survey participants: about 40% of their day. Another limitation is that ATUS does not distinguish between indoor and outdoor activities at home, two of the traditional locational demarcations used in human exposure modeling. This lack of information affects exposure estimates to both indoor and outdoor air pollutants and potentially affects non-dietary ingestion estimates for children, which can vary widely depending on whether or not a child is indoors. Finally, a detailed analysis of the work travel activity in a subsample from ATUS 2006 indicates that the coding scheme is not fully consistent with a CHAD-based exposure modeling approach. For ATUS respondents in this subsample who reported work as an activity, roughly 48% of their days were missing work travel at one or both ends of the work shift or reported within work-shift travel inconsistently. An extensive effort would be needed to recode work travel data from ATUS for EPA's exposure modeling purposes.

Assessing bisphenol A (BPA) exposure risk from long-term dietary intakes in Taiwan.

PubMed

Chen, Wei-Yu; Shen, Yi-Pei; Chen, Szu-Chieh

2016-02-01

Dietary intake is the major bisphenol A (BPA) exposure route in humans, and is a cause of BPA-related adverse effects. The large-scale exposure risk of humans to BPA through dietary sources in Taiwan is less well studied. The aim of this study was to assess the average daily dose (ADD) and hazardous quotient (HQ) of BPA exposure risk from long-term dietary intake of BPA, as well as BPA concentrations in different age-sex groups in Taiwan. We reanalyzed the BPA concentrations of regular daily food sources (rice, poultry, livestock, seafood, protein, fruits, and vegetables) and used a national dietary survey to estimate the contribution of variance to ADDs and potential human health effect for different age-sex groups. This study found that the daily consumption of chicken, pork/beef, and seafood were estimated to be 33.77 (Male)/22.65 (Female), 91.70 (M)/66.35 (F), and 54.15 (M)/40.78 (F) g/day, respectively. The highest BPA ADD was found in the 6-9 years age group (95% CI=0.0006-0.0027 mg/kg-bw/day), whereas the lowest BPA ADD was in the ≥65 years age group (0.0002-0.0020 mg/kg-bw/day). Based on the latest EFSA guidelines (0.004 mg/kg-bw/day), the 97.5 percentile HQ of BPA intake in different age-sex groups in Taiwan posed no risks through dietary intake. However, a combination of multiple exposure routes and long-term exposure in specific populations may be of concern in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

The Air Pollution Exposure Laboratory (APEL) for controlled human exposure to diesel exhaust and other inhalants: characterization and comparison to existing facilities.

PubMed

Birger, Nicholas; Gould, Timothy; Stewart, James; Miller, Mark R; Larson, Timothy; Carlsten, Chris

2011-03-01

The Air Pollution Exposure Laboratory (APEL) was designed for the controlled inhalation of human subjects to aged and diluted diesel exhaust (DE) to mimic "real-world" occupational and environmental conditions. An EPA Tier 3-compliant, 6.0 kW diesel generator is operated under discrete cyclic loads to simulate diesel on-road emissions. The engine accepts standard ultra-low sulfur diesel or a variety of alternative fuels (such as biodiesel) via a partitioned tank. A portion of raw exhaust is drawn into the primary dilution system and is diluted 9:1 with compressed air at standard temperature (20°C) and humidity (40%) levels. The exhaust is further diluted approximately 25:1 by high efficiency particulate air (HEPA)-filtered air (FA) and then aged for 4 min before entering the 4 × 6 × 7-foot exposure booth. An optional HEPA filter path immediately proximal to the booth can generate a particle-reduced (gas-enriched) exposure. In-booth particulate is read by a nephelometer to provide an instantaneous light scattering coefficient for closed-loop system control. A Scanning Mobility Particle Sizer and multi-stage impactor measures particle size distribution. Filter sampling allows determination of sessional average concentrations of size-fractionated and unfractionated particulate oxidative potential, elemental carbon, organic carbon and trace elements. Approximately 300 μg/m(3) PM(2.5) is routinely achievable at APEL and is well characterized in terms of oxidative potential and elemental components. APEL efficiently creates fresh DE, appropriately aged and diluted for human experimentation at safe yet realistic concentrations. Description of exposure characteristics allows comparison to other international efforts to deepen the current evidence base regarding the health effects of DE.

Relative importance of different exposure routes of heavy metals for humans living near a municipal solid waste incinerator.

PubMed

Li, Tong; Wan, Yi; Ben, Yujie; Fan, Senrong; Hu, Jianying

2017-07-01

The potential health effects of toxic chemicals (e.g. heavy metals) emitted by municipal solid waste incinerators (MSWIs) are of great concern to local residents, however there have been few studies on the contributions of different exposure pathways and their subsequent effects on the body burden of residents living near MSWIs. In this study, multiple exposure routes of heavy metals including Pb, Cr, Cd and Mn were assessed by investigating the metals in foods (such as vegetables, crops, meats and fruits etc.), drinking water, ambient air and soil collected surrounding an MSWI in Shenzhen, south China. Vegetable ingestion played the most important role in the total average daily dose of Pb and Cr, and cereals were the key exposure routes for Mn and Cd. Compound-specific contaminations were observed in the investigated areas, with Pb and Cr present in the surrounding environment, having accumulated to relatively high levels in the local vegetables, and the intake of contaminated vegetable foods greatly influencing the body burden of Pb and Cr. Consistently, significantly high blood concentrations of Pb and Cr were detected in the local residents compared to a referenced population, and a lack of significant differences was found for Cd and Mn. The results possibly suggested that emission of MSWI influenced the external exposure doses of the major pathways of Pb and Cr in this study, and resulted in the different body burden of metals in humans living near a MSWI. MSWI-local food-humans is an important exposure pathway for residents living near MSWI, and thus should not be neglected in developing future strategies and policies to prevent the high risks suffered by residents living near MSWIs. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Dhondt, Stijn, E-mail: stijn.dhondt@vub.ac.be; Beckx, Carolien, E-mail: Carolien.Beckx@vito.be; Degraeuwe, Bart, E-mail: Bart.Degraeuwe@vito.be

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

Epidemiological and virological differences in human clustered and sporadic infections with avian influenza A H7N9.

PubMed

Wu, Zuqun; Sha, Jianping; Yu, Zhao; Zhao, Na; Cheng, Wei; Chan, Ta-Chien; Amer, Said; Zhang, Zhiruo; Liu, Shelan

2016-08-01

Previous research has suggested that avian influenza A H7N9 has a greater potential pandemic risk than influenza A H5N1. This research investigated the difference in human clustered and sporadic cases of H7N9 virus and estimated the relative risk of clustered infections. Comparative epidemiology and virology studies were performed among 72 sporadic confirmed cases, 17 family clusters (FCs) caused by human-to-human transmission, and eight live bird market clusters (LCs) caused by co-exposure to the poultry environment. The case fatality of FCs, LCs and sporadic cases (36%, 26%, and 29%, respectively) did not differ among the three groups (p>0.05). The average age (36 years, 60 years, and 58 years), co-morbidities (31%, 60%, and 54%), exposure to birds (72%, 100%, and 83%), and H7N9-positive rate (20%, 64%, and 35%) in FCs, LCs, and sporadic cases, respectively, differed significantly (p<0.05). These higher risks were associated with increased mortality. There was no difference between primary and secondary cases in LCs (p>0.05). However, exposure to a person with confirmed avian influenza A H7N9 (primary 12% vs. secondary 95%), history of visiting a live bird market (100% vs. 59%), multiple exposures (live bird exposure and human-to-human transmission history) (12% vs. 55%), and median days from onset to antiviral treatment (6 days vs. 3 days) differed significantly between primary and secondary cases in FCs (p<0.05). Mild cases were found in 6% of primary cases vs. 32% of secondary cases in FCs (p<0.05). Twenty-five isolates from the three groups showed 99.1-99.9% homology and increased human adaptation. There was no statistical difference in the case fatality rate and limited transmission between FCs and LCs. However, the severity of the primary cases in FCs was much higher than that of the secondary cases due to the older age and greater underlying disease of the latter patients. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

Antimony exposure and speciation in human biomarkers near an active mining area in Hunan, China.

PubMed

Ye, Li; Qiu, Shixin; Li, Xinhai; Jiang, Yuxuan; Jing, Chuanyong

2018-05-28

Antimony (Sb) exposure threatens human health. To identify human biomarkers for Sb exposure, we analyzed 480 environmental samples from an active Sb mining area in Hunan, China. Elevated Sb concentrations exceeding the reference level were detected in drinking water (70% of n = 83 total samples), foods (80%, n = 188), urine (95%, n = 63), saliva (44%, n = 48), hair (80%, n = 51) and nails (83%, n = 47). Drinking water contributed 85%-100% of the average daily dose (ADD) of Sb, and the total ADD (11.7 μg/kg bodyweight/day) was up to thirty times higher than the oral reference dose (0.4 μg/kg bodyweight/day) as recommended by USEPA. A positive correlation was found between ADD and Sb content in hair (p = 0.02), but not in urine (p = 0.051), saliva (p = 0.52) or nails (p = 0.85), suggesting that hair is the best non-invasive biomarker. Micro X-ray fluorescence analysis indicated that Sb is distributed in discrete spots in hair and nails, and Sb distribution is correlated with other metals. Methylated Sb species were predominant in urine (46%-100%) and saliva (74%-100%) in collected samples, implying that the human metabolic system adopts methylation as an effective pathway to detoxify and excrete Sb. Copyright © 2018 Elsevier B.V. All rights reserved.

Spatiotemporal exposure modeling of ambient erythemal ultraviolet radiation.

PubMed

VoPham, Trang; Hart, Jaime E; Bertrand, Kimberly A; Sun, Zhibin; Tamimi, Rulla M; Laden, Francine

2016-11-24

Ultraviolet B (UV-B) radiation plays a multifaceted role in human health, inducing DNA damage and representing the primary source of vitamin D for most humans; however, current U.S. UV exposure models are limited in spatial, temporal, and/or spectral resolution. Area-to-point (ATP) residual kriging is a geostatistical method that can be used to create a spatiotemporal exposure model by downscaling from an area- to point-level spatial resolution using fine-scale ancillary data. A stratified ATP residual kriging approach was used to predict average July noon-time erythemal UV (UV Ery ) (mW/m 2 ) biennially from 1998 to 2012 by downscaling National Aeronautics and Space Administration (NASA) Total Ozone Mapping Spectrometer (TOMS) and Ozone Monitoring Instrument (OMI) gridded remote sensing images to a 1 km spatial resolution. Ancillary data were incorporated in random intercept linear mixed-effects regression models. Modeling was performed separately within nine U.S. regions to satisfy stationarity and account for locally varying associations between UV Ery and predictors. Cross-validation was used to compare ATP residual kriging models and NASA grids to UV-B Monitoring and Research Program (UVMRP) measurements (gold standard). Predictors included in the final regional models included surface albedo, aerosol optical depth (AOD), cloud cover, dew point, elevation, latitude, ozone, surface incoming shortwave flux, sulfur dioxide (SO 2 ), year, and interactions between year and surface albedo, AOD, cloud cover, dew point, elevation, latitude, and SO 2 . ATP residual kriging models more accurately estimated UV Ery at UVMRP monitoring stations on average compared to NASA grids across the contiguous U.S. (average mean absolute error [MAE] for ATP, NASA: 15.8, 20.3; average root mean square error [RMSE]: 21.3, 25.5). ATP residual kriging was associated with positive percent relative improvements in MAE (0.6-31.5%) and RMSE (3.6-29.4%) across all regions compared to NASA grids. ATP residual kriging incorporating fine-scale spatial predictors can provide more accurate, high-resolution UV Ery estimates compared to using NASA grids and can be used in epidemiologic studies examining the health effects of ambient UV.

Alcohol, Methamphetamine, and Marijuana Exposure Have Distinct Effects on the Human Placenta.

PubMed

Carter, R Colin; Wainwright, Helen; Molteno, Christopher D; Georgieff, Michael K; Dodge, Neil C; Warton, Fleur; Meintjes, Ernesta M; Jacobson, Joseph L; Jacobson, Sandra W

2016-04-01

Animal studies have demonstrated adverse effects of prenatal alcohol exposure on placental development, but few studies have examined these effects in humans. Little is known about effects of prenatal exposure to methamphetamine, marijuana, and cigarette smoking on placental development. Placentas were collected from 103 Cape Coloured (mixed ancestry) pregnant women recruited at their first antenatal clinic visit in Cape Town, South Africa. Sixty-six heavy drinkers and 37 nondrinkers were interviewed about their alcohol, cigarette smoking, and drug use at 3 antenatal visits. A senior pathologist, blinded to exposure status, performed comprehensive pathology examinations on each placenta using a standardized protocol. In multivariable regression models, effects of prenatal exposure were examined on placental size, structure, and presence of infections and meconium. Drinkers reported a binge pattern of heavy drinking, averaging 8.0 drinks/occasion across pregnancy on 1.4 d/wk. 79.6% smoked cigarettes; 22.3% used marijuana; and 17.5% used methamphetamine. Alcohol exposure was related to decreased placental weight and a smaller placenta-to-birthweight ratio. By contrast, methamphetamine was associated with larger placental weight and a larger placenta-to-birthweight ratio. Marijuana was also associated with larger placental weight. Alcohol exposure was associated with increased risk of placental hemorrhage. Prenatal alcohol, drug, and cigarette use were not associated with chorioamnionitis, villitis, deciduitis, or maternal vascular underperfusion. Alcohol and cigarette smoking were associated with a decreased risk of intrauterine passing of meconium, a sign of acute fetal stress and/or hypoxia; methamphetamine, with an increased risk. This is the first human study to show that alcohol, methamphetamine, and marijuana were associated with distinct patterns of pathology, suggesting different mechanisms mediating their effects on placental development. Given the growing body of evidence linking placental abnormalities to neurodevelopmental deficits, these findings may be important in the long-term teratogenic effects of prenatal alcohol and drug exposure. Copyright © 2016 by the Research Society on Alcoholism.

Adhesion and enrichment of metals on human hands from contaminated soil at an Arctic urban brownfield.

PubMed

Siciliano, Steven D; James, K; Zhang, Guiyin; Schafer, Alexis N; Peak, J Derek

2009-08-15

Human exposure to contaminated soils drives clean up criteria at many urban brownfields. Current risk assessment guidelines assume that humans ingest some fraction of soil smaller than 4 mm but have no estimates of what fraction of soil is ingested by humans. Here, we evaluated soil adherence to human hands for 13 agricultural soils from Saskatchewan, Canada and 17 different soils from a brownfield located in Iqaluit, Nunavut, Canada. In addition, we estimated average particle size adhering to human hands for residents of a northern urban setting. Further, we estimated how metal concentrations differed between the adhered and bulk (< 4 mm) fraction of soil. The average particle size for adhered agricultural soils was 34 microm, adhered brownfield soils was 105 microm, and particles adhered to human residentswas 36 microm. Metals were significantly enriched in these adhered fractions with an average enrichment [(adhered-bulk)/bulk] in metal concentration of 184% (113% median) for 24 different elements. Enrichment was greater for key toxicological elements of concern such as chromium (140%), copper (140%), nickel (130%), lead (110%), and zinc (130%) and was highest for silver (810%), mercury (630%), selenium (500%), and arsenic (420%). Enrichment were positively correlated with carbonate complexation constants (but not bulk solubility products) and suggests that the dominant mechanism controlling metal enrichment in these samples is a precipitation of carbonate surfaces that subsequently adsorb metals. Our results suggest that metals of toxicological concern are selectively enriched in the fraction of soil that humans incidentally ingest. Investigators should likely process soil samples through a 45 microm sieve before estimating the risk associated with contaminated soils to humans. The chemical mechanisms resulting in metal enrichment likely differ between sites but at our site were linked to surface complexation with carbonates.

Measurement of recent exposure to Phlebotomus argentipes, the vector of Indian visceral Leishmaniasis, by using human antibody responses to sand fly saliva.

PubMed

Clements, Meredith F; Gidwani, Kamlesh; Kumar, Rajiv; Hostomska, Jitka; Dinesh, Diwakar S; Kumar, Vijay; Das, Pradeep; Müller, Ingrid; Hamilton, Gordon; Volfova, Vera; Boelaert, Marleen; Das, Murari; Rijal, Suman; Picado, Albert; Volf, Petr; Sundar, Shyam; Davies, Clive R; Rogers, Matthew E

2010-05-01

Antibody (IgG) responses to the saliva of Phlebotomus argentipes were investigated using serum samples from regions of India endemic and non-endemic for visceral leishmaniasis (VL). By pre-adsorbing the sera against the saliva of the competing human-biting but non-VL vector P. papatasi, we significantly improved the specificity of a P. argentipes saliva enzyme-linked immunosorbent assay. Using this method, we observed a statistically significant correlation between antibodies to P. argenitpes saliva and the average indoor density of female sand flies. Additionally, the method was able to detect recent changes in vector exposure when sera from VL patients were assayed before, during, and after hospitalization and protected from sand fly bites under untreated bed nets. Collectively, these results highlight the utility of antibodies to P. argentipes saliva as an important tool to evaluate VL vector control programs.

Computational Fluid Dynamics Modeling of Bacillus anthracis Spore Deposition in Rabbit and Human Respiratory Airways

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

Kabilan, Senthil; Suffield, Sarah R.; Recknagle, Kurtis P.

Three-dimensional computational fluid dynamics and Lagrangian particle deposition models were developed to compare the deposition of aerosolized Bacillus anthracis spores in the respiratory airways of a human with that of the rabbit, a species commonly used in the study of anthrax disease. The respiratory airway geometries for each species were derived from computed tomography (CT) or µCT images. Both models encompassed airways that extended from the external nose to the lung with a total of 272 outlets in the human model and 2878 outlets in the rabbit model. All simulations of spore deposition were conducted under transient, inhalation-exhalation breathing conditionsmore » using average species-specific minute volumes. The highest exposure concentration was modeled in the rabbit based upon prior acute inhalation studies. For comparison, human simulation was also conducted at the same concentration. Results demonstrated that regional spore deposition patterns were sensitive to airway geometry and ventilation profiles. Due to the complex airway geometries in the rabbit nose, higher spore deposition efficiency was predicted in the upper conducting airways compared to the human at the same air concentration of anthrax spores. As a result, higher particle deposition was predicted in the conducting airways and deep lung of the human compared to the rabbit lung due to differences in airway branching pattern. This information can be used to refine published and ongoing biokinetic models of inhalation anthrax spore exposures, which currently estimate deposited spore concentrations based solely upon exposure concentrations and inhaled doses that do not factor in species-specific anatomy and physiology.« less

Computational Electromagnetic Analysis in a Human Head Model with EEG Electrodes and Leads Exposed to RF-Field Sources at 915 MHz and 1748 MHz

PubMed Central

Angelone, Leonardo M.; Bit-Babik, Giorgi; Chou, Chung-Kwang

2010-01-01

An electromagnetic analysis of a human head with EEG electrodes and leads exposed to RF-field sources was performed by means of Finite-Difference Time-Domain simulations on a 1-mm3 MRI-based human head model. RF-field source models included a half-wave dipole, a patch antenna, and a realistic CAD-based mobile phone at 915 MHz and 1748 MHz. EEG electrodes/leads models included two configurations of EEG leads, both a standard 10–20 montage with 19 electrodes and a 32-electrode cap, and metallic and high resistive leads. Whole-head and peak 10-g average SAR showed less than 20% changes with and without leads. Peak 1-g and 10-g average SARs were below the ICNIRP and IEEE guideline limits. Conversely, a comprehensive volumetric assessment of changes in the RF field with and without metallic EEG leads showed an increase of two orders of magnitude in single-voxel power absorption in the epidermis and a 40-fold increase in the brain during exposure to the 915 MHz mobile phone. Results varied with the geometry and conductivity of EEG electrodes/leads. This enhancement confirms the validity of the question whether any observed effects in studies involving EEG recordings during RF-field exposure are directly related to the RF fields generated by the source or indirectly to the RF-field-induced currents due to the presence of conductive EEG leads. PMID:20681803

Maternal prenatal cortisol and infant cognitive development: moderation by infant-mother attachment.

PubMed

Bergman, Kristin; Sarkar, Pampa; Glover, Vivette; O'Connor, Thomas G

2010-06-01

Experimental animal studies suggest that early glucocorticoid exposure may have lasting effects on the neurodevelopment of the offspring; animal studies also suggest that this effect may be eliminated by positive postnatal rearing. The relevance of these findings to humans is not known. We prospectively followed 125 mothers and their normally developing children from pregnancy through 17 months postnatal. Amniotic fluid was obtained at, on average, 17.2 weeks gestation; infants were assessed at an average age of 17 months with the Bayley Scales of Infant Development, and ratings of infant-mother attachment classification were made from the standard Ainsworth Strange Situation assessment. Prenatal cortisol exposure, indexed by amniotic fluid levels, negatively predicted cognitive ability in the infant, independent of prenatal, obstetric, and socioeconomic factors. This association was moderated by child-mother attachment: in children with an insecure attachment, the correlation was [r(54) = -.47, p < .001]; in contrast, the association was nonexistent in children who had a secure attachment [r(70) = -.05, ns]. These findings mimic experimental animal findings and provide the first direct human evidence that increased cortisol in utero is associated with impaired cognitive development, and that its impact is dependent on the quality of the mother-infant relationship. Copyright 2010 Society of Biological Psychiatry. Published by Elsevier Inc. All rights reserved.

Impact of an atrazine-based herbicide on an agrobiont wolf spider.

PubMed

Godfrey, Jake A; Rypstra, Ann L

2018-06-01

For animals that live in association with humans, a key ecological question is how anthropogenic factors influence their life history. While major negative effects are obvious, subtle non-lethal responses to anthropogenic stimuli may provide insight into the features that lead to the success of species that thrive in habitats heavily impacted by humans. Here we explored the influence of the herbicide atrazine on various life history traits of a wolf spider that thrives in agroecosystems where it is commonly applied. We found that exposure delayed maturation and increased the probability of having molting errors. Atrazine also decreased the probability of producing an egg sac after mating, but increased the average mass of the initial egg sacs that were produced while not impacting the average number of eggs inside. The total number of eggs produced from a single mating on the other hand, was increased in the presence of atrazine through the production of multiple egg sacs. Finally, adult lifespan was shortened with exposure to atrazine. These results suggest that the atrazine based herbicides that are routinely applied to agricultural fields result in altered life history traits, potentially through endocrine disruption, that may counteract one another to allow persistence. Copyright © 2018 Elsevier Ltd. All rights reserved.

An estimation of Canadian population exposure to cosmic rays.

PubMed

Chen, Jing; Timmins, Rachel; Verdecchia, Kyle; Sato, Tatsuhiko

2009-08-01

The worldwide average exposure to cosmic rays contributes to about 16% of the annual effective dose from natural radiation sources. At ground level, doses from cosmic ray exposure depend strongly on altitude, and weakly on geographical location and solar activity. With the analytical model PARMA developed by the Japan Atomic Energy Agency, annual effective doses due to cosmic ray exposure at ground level were calculated for more than 1,500 communities across Canada which cover more than 85% of the Canadian population. The annual effective doses from cosmic ray exposure in the year 2000 during solar maximum ranged from 0.27 to 0.72 mSv with the population-weighted national average of 0.30 mSv. For the year 2006 during solar minimum, the doses varied between 0.30 and 0.84 mSv, and the population-weighted national average was 0.33 mSv. Averaged over solar activity, the Canadian population-weighted average annual effective dose due to cosmic ray exposure at ground level is estimated to be 0.31 mSv.

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

NASA Astrophysics Data System (ADS)

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 to dust-bound PAHs and associated carcinogenic risk in primitive and traditional cooking practices in Pakistan.

PubMed

Kamal, Atif; Malik, Riffat Naseem; Martellini, Tania; Cincinelli, Alessandra

2015-08-01

The aim of this study was to determine the abundance and distribution of polycyclic aromatic hydrocarbons (PAHs) in dust samples collected from the selected professional cooking workplaces (WCs) and residential household cooking areas (WRs), where traditional and primitive cooking practices are still prevelent. Another aim of this study was to investigate the carcinogenic risk for Pakistani human exposure to dust-bound PAHs via the routes of inhalation, ingestion, and dermal contact. Generally, the concentration of individual congeners of PAHs in surface dust samples of WC sites was higher than those measured in WR sites (p < 0.05). The benzo(a)pyrene (B(a)P), a very high carcinogenic compound, was present in the dust samples from WC sites in the highest mean concentration (630 ng g(-1) dry weight (d.w.)). The BaP mean concentration in WC workplaces was almost eight times higher than the mean value found in WR exposure sites. Moreover, the average concentration of ∑PAHs, combustion origin PAHs (∑COMB) and sum total of 7-carcinogenic PAHs (∑7-carcinogens) were also significantly higher in WC dusts samples than that in WR workplaces. Principal component analysis (PCA) and diagnostic ratios suggested coal/wood combustion as major PAH emission sources in both exposure sites. The average incremental lifetime cancer risk (ILCR) suggested a moderate to potential high cancer risk for adults and children exposed to dust-bound PAHs in both exposure sites, in particular via both dermal and ingestion contact pathways.

Potential Exposures to Australian Bat Lyssavirus Notified in Queensland, Australia, 2009-2014.

PubMed

Si, Damin; Marquess, John; Donnan, Ellen; Harrower, Bruce; McCall, Bradley; Bennett, Sonya; Lambert, Stephen

2016-12-01

Australian bat lyssavirus (ABLV) belongs to the genus Lyssavirus which also includes classic rabies virus and the European lyssaviruses. To date, the only three known human ABLV cases, all fatal, have been reported from Queensland, Australia. ABLV is widely distributed in Australian bats, and any bite or scratch from an Australian bat is considered a potential exposure to ABLV. Potential exposure to ABLV has been a notifiable condition in Queensland since 2005. We analysed notification data for potential exposures occurring between 2009 and 2014. There were 1,515 potential exposures to ABLV notified in Queensland, with an average annual notification rate of 5.6 per 100,000 population per year. The majority of notified individuals (96%) were potentially exposed to ABLV via bats, with a small number of cases potentially exposed via two ABLV infected horses and an ABLV infected human. The most common routes of potential exposure were through bat scratches (47%) or bites (37%), with less common routes being mucous membrane/broken skin exposure to bat saliva/brain tissue (2.2%). Intentional handling of bats by the general public was the major cause of potential exposures (56% of notifications). Examples of these potential exposures included people attempting to rescue bats caught in barbed wire fences/fruit tree netting, or attempting to remove bats from a home. Following potential exposures, 1,399 cases (92%) were recorded as having appropriate post-exposure prophylaxis (PEP) as defined in national guidelines, with the remainder having documentation of refusal or incomplete PEP. Up to a quarter of notifications occurred after two days from the potential exposure, but with some delays being more than three weeks. Of 393 bats available for testing during the reporting period, 20 (5.1%) had ABLV detected, including four species of megabats (all flying foxes) and one species of microbats (yellow-bellied sheathtail bat). Public health strategies should address the strong motivation of some members of the public to help injured bats or bats in distress, by emphasising that their action may harm the bat and put themselves at risk of the fatal ABLV infection. Alternative messaging should include seeking advice from professional animal rescue groups, or in the event of human contact, public health units. Further efforts are required to ensure that when potential exposure occurs, timely reporting and appropriate post-exposure prophylaxis occur.

Potential Exposures to Australian Bat Lyssavirus Notified in Queensland, Australia, 2009−2014

PubMed Central

Si, Damin; Marquess, John; Donnan, Ellen; Harrower, Bruce; McCall, Bradley; Bennett, Sonya; Lambert, Stephen

2016-01-01

Background Australian bat lyssavirus (ABLV) belongs to the genus Lyssavirus which also includes classic rabies virus and the European lyssaviruses. To date, the only three known human ABLV cases, all fatal, have been reported from Queensland, Australia. ABLV is widely distributed in Australian bats, and any bite or scratch from an Australian bat is considered a potential exposure to ABLV. Methodology/Principal Findings Potential exposure to ABLV has been a notifiable condition in Queensland since 2005. We analysed notification data for potential exposures occurring between 2009 and 2014. There were 1,515 potential exposures to ABLV notified in Queensland, with an average annual notification rate of 5.6 per 100,000 population per year. The majority of notified individuals (96%) were potentially exposed to ABLV via bats, with a small number of cases potentially exposed via two ABLV infected horses and an ABLV infected human. The most common routes of potential exposure were through bat scratches (47%) or bites (37%), with less common routes being mucous membrane/broken skin exposure to bat saliva/brain tissue (2.2%). Intentional handling of bats by the general public was the major cause of potential exposures (56% of notifications). Examples of these potential exposures included people attempting to rescue bats caught in barbed wire fences/fruit tree netting, or attempting to remove bats from a home. Following potential exposures, 1,399 cases (92%) were recorded as having appropriate post-exposure prophylaxis (PEP) as defined in national guidelines, with the remainder having documentation of refusal or incomplete PEP. Up to a quarter of notifications occurred after two days from the potential exposure, but with some delays being more than three weeks. Of 393 bats available for testing during the reporting period, 20 (5.1%) had ABLV detected, including four species of megabats (all flying foxes) and one species of microbats (yellow-bellied sheathtail bat). Conclusions/Significance Public health strategies should address the strong motivation of some members of the public to help injured bats or bats in distress, by emphasising that their action may harm the bat and put themselves at risk of the fatal ABLV infection. Alternative messaging should include seeking advice from professional animal rescue groups, or in the event of human contact, public health units. Further efforts are required to ensure that when potential exposure occurs, timely reporting and appropriate post-exposure prophylaxis occur. PMID:28033365

Geographical scenario uncertainty in generic fate and exposure factors of toxic pollutants for life-cycle impact assessment

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

Huijbregts, Mark A.J.; Lundi, Sven; McKone, Thomas E.

In environmental life-cycle assessments (LCA), fate and exposure factors account for the general fate and exposure properties of chemicals under generic environmental conditions by means of 'evaluative' multi-media fate and exposure box models. To assess the effect of using different generic environmental conditions, fate and exposure factors of chemicals emitted under typical conditions of (1) Western Europe, (2) Australia and (3) the United States of America were compared with the multi-media fate and exposure box model USES-LCA. Comparing the results of the three evaluative environments, it was found that the uncertainty in fate and exposure factors for ecosystems and humansmore » due to choice of an evaluative environment, as represented by the ratio of the 97.5th and 50th percentile, is between a factor 2 and 10. Particularly, fate and exposure factors of emissions causing effects in fresh water ecosystems and effects on human health have relatively high uncertainty. This uncertainty i s mainly caused by the continental difference in the average soil erosion rate, the dimensions of the fresh water and agricultural soil compartment, and the fraction of drinking water coming from ground water.« less

Modifications of exposure to ambient particulate matter: Tackling bias in using ambient concentration as surrogate with particle infiltration factor and ambient exposure factor.

PubMed

Shi, Shanshan; Chen, Chen; Zhao, Bin

2017-01-01

Numerous epidemiological studies explored health risks attributed to outdoor particle pollution. However, a number of these studies routinely utilized ambient concentration as a surrogate for personal exposure to ambient particles. This simplification ignored the difference between indoor and outdoor concentrations of outdoor originated particles and may bias the estimate of particle-health associations. Intending to avoid the bias, particle infiltration factor (F inf ), which describes the penetration of outdoor particles in indoor environment, and ambient exposure factor (α), which represents the fraction of outdoor particles people are truly exposed to, are utilized as modification factors to modify outdoor particle concentration. In this study, the probabilistic distributions of annually-averaged and seasonally-averaged F inf and α were assessed for residences and residents in Beijing. F inf of a single residence and α of an individual was estimated based on the mechanisms governing particle outdoor-to-indoor migration and human time-activity pattern. With this as the core deterministic model, probabilistic distributions of F inf and α were estimated via Monte Carlo Simulation. Annually-averaged F inf of PM 2.5 and PM 10 for residences in Beijing tended to be log-normally distributed as lnN(-0.74,0.14) and lnN(-0.94,0.15) with geometric mean value as 0.47 and 0.39, respectively. Annually-averaged α of PM 2.5 and PM 10 for Beijing residents also tended to be log-normally distributed as lnN(-0.59,0.12) and lnN(-0.73,0.13) with geometric mean value as 0.55 and 0.48, respectively. As for seasonally-averaged results, F inf and α of PM 2.5 and PM 10 were largest in summer and smallest in winter. The obvious difference between these modification factors and unity suggested that modifications of ambient particle concentration need to be considered in epidemiological studies to avoid misclassifications of personal exposure to ambient particles. Moreover, considering the inter-individual difference of F inf and α may lead to a brand new perspective of particle-health associations in further epidemiological study. Copyright © 2016 Elsevier Ltd. All rights reserved.

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

PubMed

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

2014-12-01

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

An analysis of human exposure to trace elements from deliberate soil ingestion and associated health risks.

PubMed

Ngole-Jeme, Veronica M; Ekosse, Georges-Ive E; Songca, Sandile P

2018-01-01

Fifty-seven samples of soils commonly ingested in South Africa, Swaziland, Democratic Republic of Congo (DRC), and Togo were analyzed for the concentrations of arsenic (As), cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni), and zinc (Zn) and their bioaccessibility in the human gastrointestinal tract. Bioaccessibility values were used to calculate daily intake, and hazard quotient of each trace element, and chronic hazard index (CHI) of each sample. Carcinogenic risk associated with As and Ni exposure were also calculated. Mean pseudo-total concentrations of trace elements in all samples were 7.2, 83.3, 77.1, 15.4, 28.6, 24.9, 56.1, 2.8, and 26.5 mg/kg for As, Cr, Mn, Co, Ni, Cu, Zn, Cd, and Pb, respectively. Percent bioaccessibility of Pb (13-49%) and Zn (38-56%) were highest among trace elements studied. Average daily intake values were lower than their respective reference doses for ell elements except for Pb in selected samples. Samples from DRC presented the highest health risks associated with trace element exposure with most of the samples having CHI values between 0.5 and 1.0. Some samples had higher than unacceptable values of carcinogenic risk associated with As and Ni exposure. Results indicate low trace element exposure risk from ingesting most of the soil samples.

Computational modeling and statistical analyses on individual contact rate and exposure to disease in complex and confined transportation hubs

NASA Astrophysics Data System (ADS)

Wang, W. L.; Tsui, K. L.; Lo, S. M.; Liu, S. B.

2018-01-01

Crowded transportation hubs such as metro stations are thought as ideal places for the development and spread of epidemics. However, for the special features of complex spatial layout, confined environment with a large number of highly mobile individuals, it is difficult to quantify human contacts in such environments, wherein disease spreading dynamics were less explored in the previous studies. Due to the heterogeneity and dynamic nature of human interactions, increasing studies proved the importance of contact distance and length of contact in transmission probabilities. In this study, we show how detailed information on contact and exposure patterns can be obtained by statistical analyses on microscopic crowd simulation data. To be specific, a pedestrian simulation model-CityFlow was employed to reproduce individuals' movements in a metro station based on site survey data, values and distributions of individual contact rate and exposure in different simulation cases were obtained and analyzed. It is interesting that Weibull distribution fitted the histogram values of individual-based exposure in each case very well. Moreover, we found both individual contact rate and exposure had linear relationship with the average crowd densities of the environments. The results obtained in this paper can provide reference to epidemic study in complex and confined transportation hubs and refine the existing disease spreading models.

Development of retrospective quantitative and qualitative job-exposure matrices for exposures at a beryllium processing facility.

PubMed

Couch, James R; Petersen, Martin; Rice, Carol; Schubauer-Berigan, Mary K

2011-05-01

To construct a job-exposure matrix (JEM) for an Ohio beryllium processing facility between 1953 and 2006 and to evaluate temporal changes in airborne beryllium exposures. Quantitative area- and breathing-zone-based exposure measurements of airborne beryllium were made between 1953 and 2006 and used by plant personnel to estimate daily weighted average (DWA) exposure concentrations for sampled departments and operations. These DWA measurements were used to create a JEM with 18 exposure metrics, which was linked to the plant cohort consisting of 18,568 unique job, department and year combinations. The exposure metrics ranged from quantitative metrics (annual arithmetic/geometric average DWA exposures, maximum DWA and peak exposures) to descriptive qualitative metrics (chemical beryllium species and physical form) to qualitative assignment of exposure to other risk factors (yes/no). Twelve collapsed job titles with long-term consistent industrial hygiene samples were evaluated using regression analysis for time trends in DWA estimates. Annual arithmetic mean DWA estimates (overall plant-wide exposures including administration, non-production, and production estimates) for the data by decade ranged from a high of 1.39 μg/m(3) in the 1950s to a low of 0.33 μg/m(3) in the 2000s. Of the 12 jobs evaluated for temporal trend, the average arithmetic DWA mean was 2.46 μg/m(3) and the average geometric mean DWA was 1.53 μg/m(3). After the DWA calculations were log-transformed, 11 of the 12 had a statistically significant (p < 0.05) decrease in reported exposure over time. The constructed JEM successfully differentiated beryllium exposures across jobs and over time. This is the only quantitative JEM containing exposure estimates (average and peak) for the entire plant history.

Comparative risk assessment of carcinogens in alcoholic beverages using the margin of exposure approach.

PubMed

Lachenmeier, Dirk W; Przybylski, Maria C; Rehm, Jürgen

2012-09-15

Alcoholic beverages have been classified as carcinogenic to humans. As alcoholic beverages are multicomponent mixtures containing several carcinogenic compounds, a quantitative approach is necessary to compare the risks. Fifteen known and suspected human carcinogens (acetaldehyde, acrylamide, aflatoxins, arsenic, benzene, cadmium, ethanol, ethyl carbamate, formaldehyde, furan, lead, 4-methylimidazole, N-nitrosodimethylamine, ochratoxin A and safrole) occurring in alcoholic beverages were identified based on monograph reviews by the International Agency for Research on Cancer. The margin of exposure (MOE) approach was used for comparative risk assessment. MOE compares a toxicological threshold with the exposure. MOEs above 10,000 are judged as low priority for risk management action. MOEs were calculated for different drinking scenarios (low risk and heavy drinking) and different levels of contamination for four beverage groups (beer, wine, spirits and unrecorded alcohol). The lowest MOEs were found for ethanol (3.1 for low risk and 0.8 for heavy drinking). Inorganic lead and arsenic have average MOEs between 10 and 300, followed by acetaldehyde, cadmium and ethyl carbamate between 1,000 and 10,000. All other compounds had average MOEs above 10,000 independent of beverage type. Ethanol was identified as the most important carcinogen in alcoholic beverages, with clear dose response. Some other compounds (lead, arsenic, ethyl carbamate, acetaldehyde) may pose risks below thresholds normally tolerated for food contaminants, but from a cost-effectiveness point of view, the focus should be on reducing alcohol consumption in general rather than on mitigative measures for some contaminants that contribute only to a limited extent (if at all) to the total health risk. Copyright © 2012 UICC.

Estimation of the total daily oral intake of NDMA attributable to drinking water.

PubMed

Fristachi, Anthony; Rice, Glenn

2007-09-01

Disinfection with chlorine and chloramine leads to the formation of many disinfection by-products including N-Nitrosodimethylamine (NDMA). Because NDMA is a probable human carcinogen, public health officials are concerned with its occurrence in drinking water. The goal of this study was to estimate NDMA concentrations from exogenous (i.e., drinking water and food) and endogenous (i.e., formed in the human body) sources, calculate average daily doses for ingestion route exposures and estimate the proportional oral intake (POI) of NDMA attributable to the consumption of drinking water relative to other ingestion sources of NDMA. The POI is predicted to be 0.02% relative to exogenous and endogenous NDMA sources combined. When only exogenous sources are considered, the POI was predicted to be 2.7%. The exclusion of endogenously formed NDMA causes the POI to increase dramatically, reflecting its importance as a potentially major source of exposure and uncertainty in the model. Although concentrations of NDMA in foods are small and human exposure to NDMA from foods is quite low, the contribution from food is predicted to be high relative to that of drinking water. The mean concentration of NDMA in drinking water would need to increase from 2.1 x 10(-3) microg/L to 0.10 microg/L, a 47-fold increase, for the POI to reach 1%, relative to all sources of NDMA considered in our model, suggesting that drinking water consumption is most likely a minor source of NDMA exposure.

Average household exposure to newspaper coverage about the harmful effects of hormone therapy and population-based declines in hormone therapy use.

PubMed

Haas, Jennifer S; Miglioretti, Diana L; Geller, Berta; Buist, Diana S M; Nelson, David E; Kerlikowske, Karla; Carney, Patricia A; Dash, Sarah; Breslau, Erica S; Ballard-Barbash, Rachel

2007-01-01

The news media facilitated the rapid dissemination of the findings from the estrogen plus progestin therapy arm of the Women's Health Initiative (EPT-WHI). To examine the relationship between the potential exposure to newspaper coverage and subsequent hormone therapy (HT) use. DESIGN/POPULATION: Population-based cohort of women receiving mammography at 7 sites (327,144 postmenopausal women). The outcome was the monthly prevalence of self-reported HT use. Circulation data for local, regional, and national newspapers was used to create zip-code level measures of the estimated average household exposure to newspaper coverage that reported the harmful effects of HT in July 2002. Women had an average potential household exposure of 1.4 articles. There was substantial variation in the level of average household exposure to newspaper coverage; women from rural sites received less than women from urban sites. Use of HT declined for all average potential exposure groups after the publication of the EPT-WHI. HT prevalence among women who lived in areas where there was an average household exposure of at least 3 articles declined significantly more (45 to 27%) compared to women who lived in areas with <1 article (43 to 31%) during each of the subsequent 5 months (relative risks 0.86-0.92; p < .006 for all). Greater average household exposure to newspaper coverage about the harms associated with HT was associated with a large population-based decline in HT use. Further studies should examine whether media coverage directly influences the health behavior of individual women.

Social distribution of internal exposure to environmental pollution in Flemish adolescents.

PubMed

Morrens, Bert; Bruckers, Liesbeth; Hond, Elly Den; Nelen, Vera; Schoeters, Greet; Baeyens, Willy; Van Larebeke, Nicolas; Keune, Hans; Bilau, Maaike; Loots, Ilse

2012-07-01

Environmental justice research suggests that inequalities in the distribution of environmental exposure to chemical pollution systematically disadvantage the lower social strata of society. The effects of these inequalities on the human exposure to pollution are however to a large extend unknown. The purpose of this study is to assess social gradients in human biomonitoring results of a representative sample of Flemish adolescents. We investigate the associations between individual socioeconomic status (SES), measured by parental educational attainments, and internal body concentration of seven chemical compounds in biological samples of 1642 adolescents aged 14-15 in Flanders (Belgium): PCBs, HCB, DDE, lead, cadmium, benzene and PAHs. Social gradients in average and high exposure to these biomarkers were examined with geometric means and odds ratios (with 95% confidence intervals), using multiple regression models, controlling for covariates and confounders. Depending on the (type of) pollutant, adolescents with a lower SES either have higher or lower internal concentrations. Chlorinated compounds (PCBs and pesticides HCB and DDE) are positively associated with SES (higher exposures for higher SES), while heavy metals (lead and cadmium) are negatively associated (higher exposures for lower SES). For metabolites of organic compounds (benzene and PAHs) we find no association with SES. Socially constructed factors, such as dietary and lifestyle habits, play an important role in these relations. Our study suggests that the association between individual SES and the internal body concentration of exposure to environmental pollutants in Flemish adolescents is more complex than can be assumed on the basis of the environmental justice hypothesis. Copyright © 2011 Elsevier GmbH. All rights reserved.

In vitro human epidermal permeation of nicotine from electronic cigarette refill liquids and implications for dermal exposure assessment.

PubMed

Frasch, H Frederick; Barbero, Ana M

2017-11-01

Nicotine plus flavorings in a propylene glycol (PG) vehicle are the components of electronic cigarette liquids (e-liquids), which are vaporized and inhaled by the user. Dermal exposure to nicotine and e-liquids may occur among workers in mixing and filling of e-cigarettes in the manufacturing process. Inadvertent skin contact among consumers is also a concern. In vitro nicotine permeation studies using heat-separated human epidermis were performed with surrogate and two commercial e-liquids, neat and aqueous nicotine donor formulations. Steady-state fluxes (J ss ), and lag times (t lag ) were measured for each formulation. In addition, transient (4 h) exposure and finite dose (1-10 μl/cm 2 ) experiments were undertaken using one commercial e-liquid. Average J ss (μg/cm 2 /h) from formulations were: nicotine in PG (24 mg/ml): 3.97; commercial e-liquid containing menthol (25 mg/ml nicotine): 10.2; commercial e-liquid containing limonene (25 mg/ml nicotine): 23.7; neat nicotine: 175. E-liquid lag times ranged from 5 to 10 h. Absorbed fraction of nicotine from finite doses was ≈0.3 at 48 h. The data were applied to transient exposure and finite dose dermal exposure assessment models and to a simple pharmacokinetic model. Three illustrative exposure scenarios demonstrate use of the data to predict systemic uptake and plasma concentrations from dermal exposure. The data demonstrate the potential for significant nicotine absorption through skin contact with e-cigarette refill solutions and the neat nicotine used to mix them.

Concentrations of fine, ultrafine, and black carbon particles in auto-rickshaws in New Delhi, India

NASA Astrophysics Data System (ADS)

Apte, Joshua, S.; Kirchstetter, Thomas W.; Reich, Alexander, H.; Deshpande, Shyam J.; Kaushik, Geetanjali; Chel, Arvind; Marshall, Julian D.; Nazaroff, William W.

2011-08-01

Concentrations of air pollutants from vehicles are elevated along roadways, indicating that human exposure in transportation microenvironments may not be adequately characterized by centrally located monitors. We report results from ˜180 h of real-time measurements of fine particle and black carbon mass concentration (PM 2.5, BC) and ultrafine particle number concentration (PN) inside a common vehicle, the auto-rickshaw, in New Delhi, India. Measured exposure concentrations are much higher in this study (geometric mean for ˜60 trip-averaged concentrations: 190 μg m -3 PM 2.5, 42 μg m -3 BC, 280 × 10 3 particles cm -3; GSD ˜1.3 for all three pollutants) than reported for transportation microenvironments in other megacities. In-vehicle concentrations exceeded simultaneously measured ambient levels by 1.5× for PM 2.5, 3.6× for BC, and 8.4× for PN. Short-duration peak concentrations (averaging time: 10 s), attributable to exhaust plumes of nearby vehicles, were greater than 300 μg m -3 for PM 2.5, 85 μg m -3 for BC, and 650 × 10 3 particles cm -3 for PN. The incremental increase of within-vehicle concentration above ambient levels—which we attribute to in- and near-roadway emission sources—accounted for 30%, 68% and 86% of time-averaged in-vehicle PM 2.5, BC and PN concentrations, respectively. Based on these results, we estimate that one's exposure during a daily commute by auto-rickshaw in Delhi is as least as large as full-day exposures experienced by urban residents of many high-income countries. This study illuminates an environmental health concern that may be common in many populous, low-income cities.

Geographical Differences in Dietary Exposure to Perfluoroalkyl Acids between Manufacturing and Application Regions in China.

PubMed

Zhang, Haiyan; Vestergren, Robin; Wang, Thanh; Yu, Junchao; Jiang, Guibin; Herzke, Dorte

2017-05-16

Emissions of perfluoroalkyl acids (PFAAs) have increased in China over the past decade, but human exposure pathways are poorly understood. Here we analyzed 15 PFAAs in commonly consumed food items and calculated body weight normalized dietary intake rates (estimated dietary intake, EDIs) in an area with ongoing PFAA production (Hubei province; n = 121) and an urbanized coastal area (Zhejiang province; n = 106). Geographical differences in concentrations were primarily observed for perfluorooctanesulfonic acid (PFOS) and perfluorohexanesulfonic acid (PFHxS) in animal food items and short-chain PFAAs in vegetable food items. The average EDI of ∑PFAAs for adults in Hubei (998 ng kg -1 day -1 ) was more than 2 orders of magnitude higher than that in Zhejiang (9.03 ng kg -1 day -1 ). In Hubei province, the average EDI of PFOS for adults (87 ng kg -1 day -1 ) was close to or exceeded advisory guidelines used in other countries indicating health risks for the population from long-term exposure. Yet, PFOS could only account for about 10% of the EDI of ∑PFAAs in the Hubei province, which was dominated by short-chain PFAAs through consumption of vegetables. The large contribution of short-chain PFAAs to the total EDIs in manufacturing areas emphasize the need for improved exposure and hazard assessment tools of these substances.

Fluorescent biological aerosol particles: Concentrations, emissions, and exposures in a northern California residence.

PubMed

Tian, Y; Liu, Y; Misztal, P K; Xiong, J; Arata, C M; Goldstein, A H; Nazaroff, W W

2018-04-06

Residences represent an important site for bioaerosol exposure. We studied bioaerosol concentrations, emissions, and exposures in a single-family residence in northern California with 2 occupants using real-time instrumentation during 2 monitoring campaigns (8 weeks during August-October 2016 and 5 weeks during January-March 2017). Time- and size-resolved fluorescent biological aerosol particles (FBAP) and total airborne particles were measured in real time in the kitchen using an ultraviolet aerodynamic particle sizer (UVAPS). Time-resolved occupancy status, household activity data, air-change rates, and spatial distribution of size-resolved particles were also determined throughout the house. Occupant activities strongly influenced indoor FBAP levels. Indoor FBAP concentrations were an order of magnitude higher when the house was occupied than when the house was vacant. Applying an integral material-balance approach, geometric mean of total FBAP emissions from human activities observed to perturb indoor levels were in the range of 10-50 million particles per event. During the summer and winter campaigns, occupants spent an average of 10 and 8.5 hours per day, respectively, awake and at home. During these hours, the geometric mean daily-averaged FBAP exposure concentration (1-10 μm diameter) was similar for each subject at 40 particles/L for summer and 29 particles/L for winter. © 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Use of pooled samples to assess human exposure to parabens, benzophenone-3 and triclosan in Queensland, Australia

PubMed Central

Heffernan, A.L.; Baduel, C.; Toms, L.M.L.; Calafat, A.M.; Ye, X.; Hobson, P.; Broomhall, S.; Mueller, J.F.

2017-01-01

Parabens, benzophenone-3 and triclosan are common ingredients used as preservatives, ultraviolet radiation filters and antimicrobial agents, respectively. Human exposure occurs through consumption of processed food and use of cosmetics and consumer products. The aim of this study was to provide a preliminary characterisation of exposure to selected personal care product chemicals in the general Australian population. De-identified urine specimens stratified by age and sex were obtained from a community-based pathology laboratory and pooled (n = 24 pools of 100). Concentrations of free and total (sum of free plus conjugated) species of methyl, ethyl, propyl and butyl paraben, benzophenone-3 and triclosan were quantified using isotope dilution tandem mass spectrometry; with geometric means 232, 33.5, 60.6, 4.32, 61.5 and 87.7 ng/mL, respectively. Age was inversely associated with paraben concentration, and females had concentrations approximately two times higher than males. Total paraben and benzophenone-3 concentrations are significantly higher than reported worldwide, and the average triclosan concentration was more than one order of magnitude higher than in many other populations. This study provides the first data on exposure of the general Australian population to a range of common personal care product chemical ingredients, which appears to be prevalent and warrants further investigation. PMID:26368661

[Toxicological and analytical lists: chromium and its compounds].

PubMed

Minoia, C; Apostoli, P; Battaglia, A; Catenacci, G; Cottica, D; Franco, G; Pozzoli, L; Vanola, C; Candura, F; Capodaglio, E

1987-03-01

The main aspects of occupational exposure to chromium and chromium compounds are surveyed. Special attention is paid to the toxic action of this metal at the different target organs. The nutritional aspect of CrIII is examined preliminarily, and data detailing the metal contents in water and food are provided. As far the different working processes that entail occupational exposure to chromium are concerned, hygienic and environmental problems are discussed while identifying the average environment exposure to the different chemical forms of chromium (CrIII, CrIV, soluble and not soluble), as a function of the worker's tasks, and the relevant human response (total human Cr). Different hygienic and environmental standards in force in various countries and applicable to chromium compounds are compared. Additional information is given on the main aspects of chromium metabolism (absorption, distribution, excretion), and on the prevailing toxic actions, with specific reference to cancerogenesis. As far as biologic monitoring of the exposed people is concerned, the significance of Cr-U as dose-exposure indicator is discussed, also in the light of a critical review of the reference values. The report describes a series of analytical methods for the identification of chromium in aqueous and biologic matrices. The problems connected with health monitoring and fitness for work are eventually covered.

Dietary exposure of Canadians to perfluorinated carboxylates and perfluorooctane sulfonate via consumption of meat, fish, fast foods, and food items prepared in their packaging.

PubMed

Tittlemier, Sheryl A; Pepper, Karen; Seymour, Carol; Moisey, John; Bronson, Roni; Cao, Xu-Liang; Dabeka, Robert W

2007-04-18

Human exposure to perfluorinated compounds is a worldwide phenomenon; however, routes of human exposure to these compounds have not been well-characterized. Fifty-four solid food composite samples collected as part of the Canadian Total Diet Study (TDS) were analyzed for perfluorocarboxylates and perfluorooctanesulfonate (PFOS) using a methanol extraction liquid chromatography tandem mass spectrometry method. Foods analyzed included fish and seafood, meat, poultry, frozen entrées, fast food, and microwave popcorn collected from 1992 to 2004 and prepared as for consumption. Nine composites contained detectable levels of perfluorinated compounds-four meat-containing, three fish and shellfish, one fast food, and one microwave popcorn. PFOS and perfluorooctanoate (PFOA) were detected the most frequently; concentrations ranged from 0.5 to 4.5 ng/g. The average dietary intake of total perfluorocarboxylates and PFOS for Canadians was estimated to be 250 ng/day, using results from the 2004 TDS composites. A comparison with intakes of perfluorocarboxylates and PFOS via other routes (air, water, dust, treated carpeting, and apparel) suggested that diet is an important source of these compounds. There was a substantial margin of exposure between the toxicological points of reference and the magnitude of dietary intake of perfluorinated compounds for Canadians >/= 12 years old.

In-vitro ablation of fibrocartilage by XeCl excimer laser

NASA Astrophysics Data System (ADS)

Buchelt, Martin; Papaioannou, Thanassis; Fishbein, Michael C.; Peters, Werner; Beeder, Clain; Grundfest, Warren S.

1991-07-01

A 308 nm excimer laser was employed for ablation of human fibrocartilage. Experiments were conducted in vitro. The tissue response was investigated with respect to dosimetry (ablation rate versus radiant exposure) and thermal effect (thermographic analysis). Irradiation was performed via a 600 um fiber, with radiant exposures ranging between 20mj/mm2 and 80mj/mm2, at 20Hz. The ablation rates were found to range from 3um/pulse to 80um/pulse depending on the radiant exposure and/or the applied pressure on the delivery system. Thermographic analysis, during ablation, revealed maximum average temperatures of about 65 degree(s)C. Similar measurements performed, for the purpose of comparison, with a CW Nd:YAG and a CW CO2 laser showed higher values, of the order of 200 degree(s)C.

Environmental tobacco smoke particles in multizone indoor environments

NASA Astrophysics Data System (ADS)

Miller, S. L.; Nazaroff, W. W.

Environmental tobacco smoke (ETS) is a major source of human exposure to airborne particles. To better understand the factors that affect exposure, and to investigate the potential effectiveness of technical control measures, a series of experiments was conducted in a two-room test facility. Particle concentrations, size distributions, and airflow rates were measured during and after combustion of a cigarette. Experiments were varied to obtain information about the effects on exposure of smoker segregation, ventilation modification, and air filtration. The experimental data were used to test the performance of an analytical model of the two-zone environment and a numerical multizone aerosol dynamics model. A respiratory tract particle deposition model was also applied to the results to estimate the mass of ETS particles that would be deposited in the lungs of a nonsmoker exposed in either the smoking or nonsmoking room. Comparisons between the experimental data and model predictions showed good agreement. For time-averaged particle mass concentration, the average bias between model and experiments was less than 10%. The average absolute error was typically 35%, probably because of variability in particle emission rates from cigarettes. For the conditions tested, the use of a portable air filtration unit yielded 65-90% reductions in predicted lung deposition relative to the baseline scenario. The use of exhaust ventilation in the smoking room reduced predicted lung deposition in the nonsmoking room by more than 80%, as did segregating the smoker from nonsmokers with a closed door.

Population Physiologically-Based Pharmacokinetic Modeling for the Human Lactational Transfer of PCB 153 with Consideration of Worldwide Human Biomonitoring Results

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

Redding, Laurel E.; Sohn, Michael D.; McKone, Thomas E.

2008-03-01

We developed a physiologically based pharmacokinetic model of PCB 153 in women, and predict its transfer via lactation to infants. The model is the first human, population-scale lactational model for PCB 153. Data in the literature provided estimates for model development and for performance assessment. Physiological parameters were taken from a cohort in Taiwan and from reference values in the literature. We estimated partition coefficients based on chemical structure and the lipid content in various body tissues. Using exposure data in Japan, we predicted acquired body burden of PCB 153 at an average childbearing age of 25 years and comparemore » predictions to measurements from studies in multiple countries. Forward-model predictions agree well with human biomonitoring measurements, as represented by summary statistics and uncertainty estimates. The model successfully describes the range of possible PCB 153 dispositions in maternal milk, suggesting a promising option for back estimating doses for various populations. One example of reverse dosimetry modeling was attempted using our PBPK model for possible exposure scenarios in Canadian Inuits who had the highest level of PCB 153 in their milk in the world.« less

The levels of polycyclic aromatic hydrocarbons (PAHs) in human milk and exposure risk to breastfed infants in petrochemical industrialized Lanzhou Valley, Northwest China.

PubMed

Wang, Li; Liu, Aiping; Zhao, Yuan; Mu, Xi; Huang, Tao; Gao, Hong; Ma, Jianmin

2018-06-01

We investigated in this paper the presence of PAHs in human milk from lactating women residing in Lanzhou, a petrochemical industrialized valley city in Northwest China. The PAH concentration levels in human milk samples from 98 healthy women were determined by gas chromatography/mass spectrometry (GC/MS). The associations between the lifestyle factors and the PAHs levels of human milk were analyzed. Moreover, we applied principal component analysis (PCA) method to gain a better insight into the similarities or dissimilarities of the human milk PAH loads and different pathways of source exposure. In addition, the exposure risks of breastfed infants due to PAH ingestion via breast milk were assessed and the relative breast-feeding risk to the total intake dose of infants was addressed. The results showed that the average fat-normalized human milk ∑ 15 PAHs concentrations for the lactating women residing in four districts of Lanzhou, namely, Xigu, Anning, Qilihe, and Chengguan were 320.40, 270.36, 374.04, and 259.84 ng/g of fat, respectively. The ∑ 15 PAHs of human milk from the lactating women of Qilihe District exhibited the highest concentration level, while the concentration level for women from Xigu District is the second highest for the observed human milk ∑ 15 PAHs. And the corresponding BaPeq concentrations for women in Xigu, Anning, Qilihe, and Chengguan districts were 58.29, 47.95, 65.13, and 45.60 ng/g of fat, respectively. A significant correlation was only found between human milk and living district environment (p < 0.05). Although the Spearman correlation analysis showed that there were no significant correlation existing between other lifestyle and human milk PAHs, we confirmed that consuming barbecue food could elevate PAHs levels in human milk: the barbecue intake frequency caused 10% fluctuation of ∑ 15 PAHs concentration between high frequency and low frequency group in our study. Furthermore, the exposure to second-hand smoke can also increase the ∑ 15 PAHs levels in human milk by 4 to 11% here. Ingestion doses of PAHs by infants (19.37-77.75 ng kg -1  day -1 ) were much higher than the inhalation doses (2.83-16.48 ng kg -1  day -1 ), which indicated that the ingestion is the main exposure risk pathway for infants. Since there are limited guidelines and standards for PAHs ingestion dose in human milk by infant, we compared the ingestion dose of BaP with the upper bound estimates of BaP dietary exposure of 108 ng kg -1  day -1 for toddlers of ages between 1.5 and 2.5 years of age in the UK reported by Committee on Toxicity of Chemicals in Food (COT) and the data we obtained were lower than this upper bound. However, the estimated margin of exposure (MOE) values of BaP-MOE, PAH2-MOE, PAH4-MOE, and PAH8-MOE were smaller than 10,000 which indicated that there are potential hazard for breastfed infants consuming these human milk samples.

An Assessment of Dietary Exposure to Cadmium in Residents of Guangzhou, China.

PubMed

Zhang, Weiwei; Liu, Yungang; Liu, Yufei; Liang, Boheng; Zhou, Hongwei; Li, Yingyue; Zhang, Yuhua; Huang, Jie; Yu, Chao; Chen, Kuncai

2018-03-20

Cadmium and its compounds are human carcinogens with severe organ toxicity, and their contamination of agricultural soil in China has been frequently reported; however, the dietary exposure to cadmium in residents and the relevant health risk have seldom been reported. In this study, the concentration of cadmium in various types of food collected from 2013 to 2015 were analyzed using graphite furnace atomic absorption spectrometry, and the dietary exposure to cadmium assessed based on a dietary survey in 2976 Guangzhou residents. In total, 3074 out of 4039 food samples had cadmium levels above the limit of detection. The mean ± standard deviation (50th, 95th percentile) cadmium content in all samples was 159.0 ± 112.7 (8.6, 392.4) μg/kg, with levels ranging from 1.0 to 7830 μg/kg. Using the mean cadmium concentrations, the average monthly dietary exposure of Guangzhou residents to cadmium was 14.4 (μg/kg body weight (BW), accounting for 57.6% of the provisional tolerable monthly intake (PTMI). Rice, laver, vegetables, and live aquatic products were the main sources of cadmium intake, on average accounting for 89% of the total value. The dietary cadmium exposure in high consumers (95th percentile food consumption) was 41.0 μg/kg·BW/month, accounting for 163% of the PTMI. Additionally, dietary cadmium exposure at mean consumption but high cadmium food concentration (95th percentile) was 32.3 μg/kg·BW/month, corresponding to 129% of the PTMI. The level of dietary exposure to cadmium in most Guangzhou residents was within the safety limit, thus increased health risk from dietary cadmium exposure is low at present. However, continued efforts by local governments to monitor the levels of cadmium in the four main food categories contributing to exposure are necessary.

Measurements of long-term external and internal radiation exposure of inhabitants of some villages of the Bryansk region of Russia after the Chernobyl accident.

PubMed

Bernhardsson, C; Zvonova, I; Rääf, C; Mattsson, S

2011-10-15

A Nordic-Soviet programme was initiated in 1990 to evaluate the external and internal radiation exposure of the inhabitants of several villages in the Bryansk region of Russia. This area was one of the number of areas particularly affected by the nuclear accident at the Chernobyl Nuclear Power Plant in 1986. Measurements were carried out yearly until 1998 and after that more irregularly; in 2000, 2006 and 2008 respectively. The effective dose estimates were based on individual thermoluminescent dosemeters and on in vivo measurements of the whole body content of (137)Cs (and (134)Cs during the first years of the programme). The decrease in total effective dose during the almost 2 decade follow-up was due to a continuous decrease in the dominating external exposure and a less decreasing but highly variable exposure from internal irradiation. In 2008, the observed average effective dose (i.e. the sum of external and internal exposure) from Chernobyl (137)Cs to the residents was estimated to be 0.3mSv y(-1). This corresponds to 8% of the estimated annual dose in 1990 and to 1% of the estimated annual dose in 1986. As a mean for the population group and for the period of the present study (2006-2008), the average yearly effective dose from Chernobyl cesium was comparable to the absorbed dose obtained annually from external exposure to cosmic radiation plus internal exposure to naturally occurring radionuclides in the human body. Our data indicate that the effective dose from internal exposure is becoming increasingly important as the body burdens of Chernobyl (137)Cs are decreasing more slowly than the external exposure. However, over the years there have been large individual variations in both the external and internal effective doses, as well as differences between the villages investigated. These variations and differences are presented and discussed in this paper. Copyright © 2011 Elsevier B.V. All rights reserved.

An Assessment of Dietary Exposure to Cadmium in Residents of Guangzhou, China

PubMed Central

Zhang, Weiwei; Liu, Yungang; Liu, Yufei; Liang, Boheng; Zhou, Hongwei; Li, Yingyue; Zhang, Yuhua; Huang, Jie; Yu, Chao; Chen, Kuncai

2018-01-01

Cadmium and its compounds are human carcinogens with severe organ toxicity, and their contamination of agricultural soil in China has been frequently reported; however, the dietary exposure to cadmium in residents and the relevant health risk have seldom been reported. In this study, the concentration of cadmium in various types of food collected from 2013 to 2015 were analyzed using graphite furnace atomic absorption spectrometry, and the dietary exposure to cadmium assessed based on a dietary survey in 2976 Guangzhou residents. In total, 3074 out of 4039 food samples had cadmium levels above the limit of detection. The mean ± standard deviation (50th, 95th percentile) cadmium content in all samples was 159.0 ± 112.7 (8.6, 392.4) μg/kg, with levels ranging from 1.0 to 7830 μg/kg. Using the mean cadmium concentrations, the average monthly dietary exposure of Guangzhou residents to cadmium was 14.4 (μg/kg body weight (BW), accounting for 57.6% of the provisional tolerable monthly intake (PTMI). Rice, laver, vegetables, and live aquatic products were the main sources of cadmium intake, on average accounting for 89% of the total value. The dietary cadmium exposure in high consumers (95th percentile food consumption) was 41.0 μg/kg·BW/month, accounting for 163% of the PTMI. Additionally, dietary cadmium exposure at mean consumption but high cadmium food concentration (95th percentile) was 32.3 μg/kg·BW/month, corresponding to 129% of the PTMI. The level of dietary exposure to cadmium in most Guangzhou residents was within the safety limit, thus increased health risk from dietary cadmium exposure is low at present. However, continued efforts by local governments to monitor the levels of cadmium in the four main food categories contributing to exposure are necessary. PMID:29558399

Stochastic dosimetry model for radon progeny in the rat lung.

PubMed

Winkler-HeiI, R; Hofmann, W; Hussain, M

2014-07-01

The stochastic dosimetry model presented here considers the distinctly asymmetric, stochastic branching pattern reported in morphometric measurements. This monopodial structure suggests that an airway diameter is a more appropriate morphometric parameter to classify bronchial dose distributions for inhaled radon progeny than the commonly assigned airway generation numbers. Bronchial doses were calculated for the typical exposure conditions reported for the Pacific Northwest National Laboratory rat inhalation studies, yielding an average bronchial dose of 7.75 mGy WLM(-1). If plotted as functions of airway generations, the resulting dose distributions are highest in the central bronchial airways, while significantly decreasing towards peripheral generations. However, if plotted as functions of airway diameters, doses are much more uniformly distributed among bronchial airways. The comparison between rat and human lungs indicates that dose conversion coefficients for the rat lung are higher than the corresponding values for the human lung by a factor of 1.34 for the experimental PNNL exposure conditions, and of 1.25 for typical human indoor conditions. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Inhibitory effect of sodium hypochlorite and chlorhexidine digluconate in clinical isolates of Sporothrix schenckii.

PubMed

Madrid, Isabel Martins; Mattei, Antonella Souza; Santin, Rosema; dos Reis Gomes, Angelita; Cleff, Marlete Brum; Meireles, Mário Carlos Araújo

2012-05-01

The susceptibility of Sporothrix schenckii isolates from clinical cases of canine, feline and human sporotrichosis, and from the environment, was evaluated with 4% sodium hypochlorite and 6.6% chlorhexidine digluconate using the broth microdilution, agar diffusion and direct exposure techniques. The minimal inhibitory concentration was smaller than 0.8% for chlorhexidine digluconate and between 8% and 4% for sodium hypochlorite. Inhibition zones were not found in agar diffusion for sodium hypochlorite, and zones averaging 1.9 mm were found for chlorhexidine digluconate. In the direct exposure test, sodium hypochlorite demonstrated best performance at 20 min of contact, as chlorhexidine digluconate presented little antimicrobial activity. © 2011 Blackwell Verlag GmbH.

Spatiotemporal analysis and human exposure assessment on polycyclic aromatic hydrocarbons in indoor air, settled house dust, and diet: A review.

PubMed

Ma, Yuning; Harrad, Stuart

2015-11-01

This review summarizes the published literature on the presence of polycyclic aromatic hydrocarbons (PAH) in indoor air, settled house dust, and food, and highlights geographical and temporal trends in indoor PAH contamination. In both indoor air and dust, ΣPAH concentrations in North America have decreased over the past 30 years with a halving time of 6.7±1.9years in indoor air and 5.0±2.3 years in indoor dust. In contrast, indoor PAH concentrations in Asia have remained steady. Concentrations of ΣPAH in indoor air are significantly (p<0.01) higher in Asia than North America. In studies recording both vapor and particulate phases, the global average concentration in indoor air of ΣPAH excluding naphthalene is between 7 and 14,300 ng/m(3). Over a similar period, the average ΣPAH concentration in house dust ranges between 127 to 115,817ng/g. Indoor/outdoor ratios of atmospheric concentrations of ΣPAH have declined globally with a half-life of 6.3±2.3 years. While indoor/outdoor ratios for benzo[a]pyrene toxicity equivalents (BaPeq) declined in North America with a half-life of 12.2±3.2 years, no significant decline was observed when data from all regions were considered. Comparison of the global database, revealed that I/O ratios for ΣPAH (average=4.3±1.3), exceeded significantly those of BaPeq (average=1.7±0.4) in the same samples. The significant decline in global I/O ratios suggests that indoor sources of PAH have been controlled more effectively than outdoor sources. Moreover, the significantly higher I/O ratios for ΣPAH compared to BaPeq, imply that indoor sources of PAH emit proportionally more of the less carcinogenic PAH than outdoor sources. Dietary exposure to PAH ranges from 137 to 55,000 ng/day. Definitive spatiotemporal trends in dietary exposure were precluded due to relatively small number of relevant studies. However, although reported in only one study, PAH concentrations in Chinese diets exceeded those in diet from other parts of the world, a pattern consistent with the spatial trends observed for concentrations of PAH in indoor air. Evaluation of human exposure to ΣPAH via inhalation, dust and diet ingestion, suggests that while intake via diet and inhalation exceeds that via dust ingestion; all three pathways contribute and merit continued assessment. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of exposure to intermittent versus continuous red light on human circadian rhythms, melatonin suppression, and pupillary constriction.

PubMed

Ho Mien, Ivan; Chua, Eric Chern-Pin; Lau, Pauline; Tan, Luuan-Chin; Lee, Ivan Tian-Guang; Yeo, Sing-Chen; Tan, Sara Shuhui; Gooley, Joshua J

2014-01-01

Exposure to light is a major determinant of sleep timing and hormonal rhythms. The role of retinal cones in regulating circadian physiology remains unclear, however, as most studies have used light exposures that also activate the photopigment melanopsin. Here, we tested the hypothesis that exposure to alternating red light and darkness can enhance circadian resetting responses in humans by repeatedly activating cone photoreceptors. In a between-subjects study, healthy volunteers (n = 24, 21-28 yr) lived individually in a laboratory for 6 consecutive days. Circadian rhythms of melatonin, cortisol, body temperature, and heart rate were assessed before and after exposure to 6 h of continuous red light (631 nm, 13 log photons cm(-2) s(-1)), intermittent red light (1 min on/off), or bright white light (2,500 lux) near the onset of nocturnal melatonin secretion (n = 8 in each group). Melatonin suppression and pupillary constriction were also assessed during light exposure. We found that circadian resetting responses were similar for exposure to continuous versus intermittent red light (P = 0.69), with an average phase delay shift of almost an hour. Surprisingly, 2 subjects who were exposed to red light exhibited circadian responses similar in magnitude to those who were exposed to bright white light. Red light also elicited prolonged pupillary constriction, but did not suppress melatonin levels. These findings suggest that, for red light stimuli outside the range of sensitivity for melanopsin, cone photoreceptors can mediate circadian phase resetting of physiologic rhythms in some individuals. Our results also show that sensitivity thresholds differ across non-visual light responses, suggesting that cones may contribute differentially to circadian resetting, melatonin suppression, and the pupillary light reflex during exposure to continuous light.

FDTD analysis of human body-core temperature elevation due to RF far-field energy prescribed in the ICNIRP guidelines.

PubMed

Hirata, Akimasa; Asano, Takayuki; Fujiwara, Osamu

2007-08-21

This study investigated the relationship between the specific absorption rate and temperature elevation in an anatomically-based model named NORMAN for exposure to radio-frequency far fields in the ICNIRP guidelines (1998 Health Phys. 74 494-522). The finite-difference time-domain method is used for analyzing the electromagnetic absorption and temperature elevation in NORMAN. In order to consider the variability of human thermoregulation, parameters for sweating are derived and incorporated into a conventional sweating formula. First, we investigated the effect of blood temperature variation modeling on body-core temperature. The computational results show that the modeling of blood temperature variation was the dominant factor influencing the body-core temperature. This is because the temperature in the inner tissues is elevated via the circulation of blood whose temperature was elevated due to EM absorption. Even at different frequencies, the body-core temperature elevation at an identical whole-body average specific absorption rate (SAR) was almost the same, suggesting the effectiveness of the whole-body average SAR as a measure in the ICNIRP guidelines. Next, we discussed the effect of sweating on the temperature elevation and thermal time constant of blood. The variability of temperature elevation caused by the sweating rate was found to be 30%. The blood temperature elevation at the basic restriction in the ICNIRP guidelines of 0.4 W kg(-1) is 0.25 degrees C even for a low sweating rate. The thermal time constant of blood temperature elevation was 23 min and 52 min for a man with a lower and a higher sweating rate, respectively, which is longer than the average time of the SAR in the ICNIRP guidelines. Thus, the whole-body average SAR required for blood temperature elevation of 1 degrees C was 4.5 W kg(-1) in the model of a human with the lower sweating coefficients for 60 min exposure. From a comparison of this value with the basic restriction in the ICNIRP guidelines of 0.4 W kg(-1), the safety factor was 11.

Exposure of infants to ochratoxin A with breast milk.

PubMed

Muñoz, K; Blaszkewicz, M; Campos, V; Vega, M; Degen, G H

2014-03-01

The nephrotoxic and carcinogenic mycotoxin ochratoxin A (OTA) is a worldwide contaminant in food commodities and also found frequently in human biological fluids. Dietary contaminants ingested by nursing mothers can appear in breast milk. But the rate of lactational transfer of OTA has not been investigated so far at various stages of breastfeeding. Therefore, and to investigate OTA exposure of Chilean infants, we conducted a longitudinally designed study in mother-child pairs (n = 21) with parallel collection of maternal blood, milk and of infant urine samples over a period of up to 6 months. Validated analytical methods were applied to determine OTA concentrations in all biological samples (n = 134). OTA was detected in almost all maternal blood plasma, at concentrations ranging between 72 and 639 ng/L. The OTA concentrations in breast milk were on average one quarter of those measured in plasma (M/P ratio 0.25). Interestingly, a higher fraction of circulating OTA was excreted in colostrum (M/P 0.4) than with mature milk (M/P ≤ 0.2). Infants exposure was calculated as daily intake from our new data for OTA levels in breast milk, and taking into account milk consumption and body weight as additional variables: Chilean infants have an average intake of 12.7 ± 9.1 ng/kg bw during the first 6 days after delivery while intake with mature milk results in average values close to 5.0 ng/kg bw/day. Their OTA exposure is discussed in the context of tolerable intake values suggested by different scientific bodies. Moreover, the study design enabled a comparison of OTA intake and infant urine concentrations over the breastfeeding period. The statistical analysis of n = 27 paired values showed a good correlation (r = 0.57) for this type of studies and thereby confirms that urinary OTA analysis in infants is a valid biomarker of exposure.

Risk of silicosis in a Colorado mining community.

PubMed

Kreiss, K; Zhen, B

1996-11-01

We investigated exposure-response relations for silicosis among 134 men over age 40 who had been identified in a previous community-based random sample study in a mining town. Thirty-two percent of the 100 dust-exposed subjects had radiologic profusions of small opacities of I/O or greater at a mean time since first silica exposure of 36.1 years. Of miners with cumulative silica exposures of 2 mg/m3-years or less, 20% had silicosis; of miners accumulating > 2 mg/m3 years, 63% had silicosis. Average silica exposure was also strongly associated with silicosis prevalence rates, with 13% silicotics among those with average exposure of 0.025-0.05 mg/m3, 34% among those with exposures of > 0.05-0.1 mg/m3, and 75% among those with average exposures > 0.1 mg/m3. Logistic regression models demonstrated that time since last silica exposure and either cumulative silica exposure or a combination of average silica exposure and duration of exposure predicted silicosis risk. Exposure-response relations were substantially higher using measured silica exposures than using estimated silica exposures based on measured dust exposures assuming a constant silica proportion of dust, consistent with less exposure misclassification. The risk of silicosis found in this study is higher than has been found in workforce studies having no follow-up of those leaving the mining industry and in studies without job title-specific silica measurements, but comparable to several recent studies of dust exposure-response relationships which suggest that a permissible exposure limit of 0.1 mg/m3 for silica does not protect against radiologic silicosis.

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

PubMed Central

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

2004-01-01

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

Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit

PubMed Central

Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J.; Banfield, Jillian F.; Nazaroff, William W.

2016-01-01

Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses’ station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3–1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3–10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37–81%. Near-room indoor emissions and outdoor sources contributed 18–59% and 1–5%, respectively. Airborne particle levels in the size range 1–10 μm showed strong dependence on human activities, indicating the importance of indoor-generated particles for infant’s exposure to airborne particulate matter in the NICU. PMID:27175913

Concentrations and Sources of Airborne Particles in a Neonatal Intensive Care Unit.

PubMed

Licina, Dusan; Bhangar, Seema; Brooks, Brandon; Baker, Robyn; Firek, Brian; Tang, Xiaochen; Morowitz, Michael J; Banfield, Jillian F; Nazaroff, William W

2016-01-01

Premature infants in neonatal intensive care units (NICUs) have underdeveloped immune systems, making them susceptible to adverse health consequences from air pollutant exposure. Little is known about the sources of indoor airborne particles that contribute to the exposure of premature infants in the NICU environment. In this study, we monitored the spatial and temporal variations of airborne particulate matter concentrations along with other indoor environmental parameters and human occupancy. The experiments were conducted over one year in a private-style NICU. The NICU was served by a central heating, ventilation and air-conditioning (HVAC) system equipped with an economizer and a high-efficiency particle filtration system. The following parameters were measured continuously during weekdays with 1-min resolution: particles larger than 0.3 μm resolved into 6 size groups, CO2 level, dry-bulb temperature and relative humidity, and presence or absence of occupants. Altogether, over sixteen periods of a few weeks each, measurements were conducted in rooms occupied with premature infants. In parallel, a second monitoring station was operated in a nearby hallway or at the local nurses' station. The monitoring data suggest a strong link between indoor particle concentrations and human occupancy. Detected particle peaks from occupancy were clearly discernible among larger particles and imperceptible for submicron (0.3-1 μm) particles. The mean indoor particle mass concentrations averaged across the size range 0.3-10 μm during occupied periods was 1.9 μg/m3, approximately 2.5 times the concentration during unoccupied periods (0.8 μg/m3). Contributions of within-room emissions to total PM10 mass in the baby rooms averaged 37-81%. Near-room indoor emissions and outdoor sources contributed 18-59% and 1-5%, respectively. Airborne particle levels in the size range 1-10 μm showed strong dependence on human activities, indicating the importance of indoor-generated particles for infant's exposure to airborne particulate matter in the NICU.

Use of passive samplers to measure atmospheric ammonia levels in a high-density industrial hog farm area of eastern North Carolina

NASA Astrophysics Data System (ADS)

Wilson, Sacoby M.; Serre, Marc L.

Hog concentrated animal feeding operations (CAFOs) in North Carolina release ammonia (NH 3), hydrogen sulfide, VOCs, and particulate matter to the atmosphere. These operations are located mainly in the NC coastal plain and can create potential health hazards for nearby human populations. Limited work has been performed to measure NH 3 at the community level to assess potential human exposure. In an effort to address this issue, a study was designed to measure NH 3 levels near hog CAFOs and community locations (i.e. homes and schools) in Eastern NC. NH 3 was collected using passive diffusion tubes in triplicate exposed primarily in weekly intervals. Sampling occurred from October 2003 to May 2004 (20 sites) and from July 2004 to October 2004 (23 sites) at varying distances from hog CAFOs in close proximity to homes and schools. Average weekly NH3 levels were measured as mass (μg NH 3-N) and converted to concentration (ppb). Mean level of 13.8 ppb near homes and schools (<2 km) was 4-12 times greater than ambient background levels (1-3 ppb), reaching as high as 80 ppb. Exposed sites (<2 km from a hog CAFO) had a mean level of 12.8 ppb which was over 2 times higher than the mean level of 5.5 ppb at less exposed sites (>2 km from a hog CAFO). The study establishes that passive sampling can be effectively used to measure average atmospheric ammonia levels at community locations near hog CAFOs in Eastern NC. The collected data indicate the relative exposure for human populations who live near a hog CAFO. The closer a populace is to the hog CAFO, the more intense the exposure. These results require more validation in the field by comparison to a reference method.

Pneumonic Tularemia in Rabbits Resembles the Human Disease as Illustrated by Radiographic and Hematological Changes after Infection

PubMed Central

Reed, Douglas S.; Smith, Le'Kneitah; Dunsmore, Tammy; Trichel, Anita; Ortiz, Luis A.; Cole, Kelly Stefano; Barry, Eileen

2011-01-01

Background Pneumonic tularemia is caused by inhalation of the gram negative bacterium, Francisella tularensis. Because of concerns that tularemia could be used as a bioterrorism agent, vaccines and therapeutics are urgently needed. Animal models of pneumonic tularemia with a pathophysiology similar to the human disease are needed to evaluate the efficacy of these potential medical countermeasures. Principal Findings Rabbits exposed to aerosols containing Francisella tularensis strain SCHU S4 developed a rapidly progressive fatal pneumonic disease. Clinical signs became evident on the third day after exposure with development of a fever (>40.5°C) and a sharp decline in both food and water intake. Blood samples collected on day 4 found lymphopenia and a decrease in platelet counts coupled with elevations in erythrocyte sedimentation rate, alanine aminotransferase, cholesterol, granulocytes and monocytes. Radiographs demonstrated the development of pneumonia and abnormalities of intestinal gas consistent with ileus. On average, rabbits were moribund 5.1 days after exposure; no rabbits survived exposure at any dose (190–54,000 cfu). Gross evaluation of tissues taken at necropsy showed evidence of pathology in the lungs, spleen, liver, kidney and intestines. Bacterial counts confirmed bacterial dissemination from the lungs to the liver and spleen. Conclusions/Significance The pathophysiology of pneumonic tularemia in rabbits resembles what has been reported for humans. Rabbits therefore are a relevant model of the human disease caused by type A strains of F. tularensis. PMID:21931798

Health risk of inhalation exposure to sub-10 µm particulate matter and gaseous pollutants in an urban-industrial area in South Africa: an ecological study

PubMed Central

Morakinyo, Oyewale Mayowa; Adebowale, Ayo Stephen; Mokgobu, Matlou Ingrid; Mukhola, Murembiwa Stanley

2017-01-01

Objective To assess the health risks associated with exposure to particulate matter (PM10), sulphur dioxide (SO2), nitrogen dioxide (NO2), carbon monoxide (CO) and ozone (O3). Design The study is an ecological study that used the year 2014 hourly ambient pollution data. Setting The study was conducted in an industrial area located in Pretoria West, South Africa. The area accommodates a coal-fired power station, metallurgical industries such as a coke plant and a manganese smelter. Data and method Estimate of possible health risks from exposure to airborne PM10, SO2, NO2, CO and O3 was performed using the US Environmental Protection Agency human health risk assessment framework. A scenario-assessment approach where normal (average exposure) and worst-case (continuous exposure) scenarios were developed for intermediate (24-hour) and chronic (annual) exposure periods for different exposure groups (infants, children, adults). The normal acute (1-hour) exposure to these pollutants was also determined. Outcome measures Presence or absence of adverse health effects from exposure to airborne pollutants. Results Average annual ambient concentration of PM10, NO2 and SO2 recorded was 48.3±43.4, 11.50±11.6 and 18.68±25.4 µg/m3, respectively, whereas the South African National Ambient Air Quality recommended 40, 40 and 50 µg/m3 for PM10, NO2 and SO2, respectively. Exposure to an hour's concentration of NO2, SO2, CO and O3, an 8-hour concentration of CO and O3, and a 24-hour concentration of PM10, NO2 and SO2 will not likely produce adverse effects to sensitive exposed groups. However, infants and children, rather than adults, are more likely to be affected. Moreover, for chronic annual exposure, PM10, NO2 and SO2 posed a health risk to sensitive individuals, with the severity of risk varying across exposed groups. Conclusions Long-term chronic exposure to airborne PM10, NO2 and SO2 pollutants may result in health risks among the study population. PMID:28289048

Underwater, low-frequency noise in a coastal sea turtle habitat.

PubMed

Samuel, Y; Morreale, S J; Clark, C W; Greene, C H; Richmond, M E

2005-03-01

Underwater sound was recorded in one of the major coastal foraging areas for juvenile sea turtles in the Peconic Bay Estuary system in Long Island, New York. The recording season of the underwater environment coincided with the sea turtle activity season in an inshore area where there is considerable boating and recreational activity, especially during the summer between Independence Day and Labor Day. Within the range of sea turtle hearing, average noise pressure reached 110 dB during periods of high human activity and diminished proportionally, down to 80 dB, with decreasing human presence. Therefore, during much of the season when sea turtles are actively foraging in New York waters, their coastal habitats are flooded with underwater noise. During the period of highest human activity, average noise pressures within the range of frequencies heard by sea turtles were greater by over two orders of magnitude (26 dB) than during the lowest period of human activity. Sea turtles undoubtedly are exposed to high levels of noise, most of which is anthropogenic. Results suggest that continued exposure to existing high levels of pervasive anthropogenic noise in vital sea turtle habitats and any increase in noise could affect sea turtle behavior and ecology.

Human Plant Exposures Reported to a Regional (Southwestern) Poison Control Center Over 8 Years.

PubMed

Enfield, Ben; Brooks, Daniel E; Welch, Sharyn; Roland, Maureen; Klemens, Jane; Greenlief, Kim; Olson, Rachel; Gerkin, Richard D

2018-03-01

There is little published data about human plant exposures reported to US poison control centers (PCCs). A retrospective chart review of all reported plant exposures to a single regional PCC between January 1, 2003 and December 31, 2010 was done to understand better the characteristics of plant exposure cases. Specific generic plant codes were used to identify cases. Recorded variables included patient demographics, plant involved, exposure variables, symptoms, management site, treatments, and outcome. Univariate and multivariate regression was used to identify outcome predictors. A total of 6492 charts met inclusion criteria. The average age was 16.6 years (2 months-94 years); 52.4% were male. The most common exposure reason was unintentional (98%), and the majority (92.4%) occurred at the patient's home. Ingestions (58.3%) and dermal exposures (34.3%) accounted for most cases. Cactus (27.5%), oleander (12.5%), Lantana (5.7%), and Bougainvillea (3.8%) were most commonly involved. Symptoms developed in 47.1% of patients, and were more likely to occur following Datura (66.7%), and Morning Glory or Milkweed (25% each) exposures. Almost 94% of patients were managed onsite (home) and only 5.2% involved evaluation in a health care facility (HCF). Only 37 (0.6%) patients required hospital admission, and 2.9% of cases resulted in more than minimal effects. Exposures resulting in more than minimal clinical effects were predicted by several variables: abnormal vital signs (OR = 35.62), abnormal labs (OR = 14.87), and management at a HCF (OR = 7.37). Hospital admissions were increased for patients already at a HCF (OR = 54.01), abnormal vital signs (OR = 23.28), and intentional exposures (OR = 14.7). Plant exposures reported to our poison control center were typically unintentional ingestions occurring at home. Most patients were managed onsite and few developed significant symptoms.

Geographical and temporal patterns of rabies post exposure prophylaxis (PEP) incidence in humans in the Mekong River Delta and Southeast Central Coast regions in Vietnam from 2005 to 2015

PubMed Central

Thiem, Vu Dinh; Anh, Dang Duc; Duong, Tran Nhu; Lee, Mihye; Grace, Delia; Nguyen-Viet, Hung

2018-01-01

Background In Vietnam, rabies has been a notifiable disease for more than 40 years. Over the last five years, on average, more than 350,000 people per year have been bitten by dogs and cats while more than 80 human deaths have been reported yearly. No studies have been conducted to evaluate the geographical and temporal patterns of rabies in humans in Vietnam. Therefore, the main objective of this study was to assess the geographical and temporal distributions of rabies post exposure prophylaxis (PEP) incidence in humans in Vietnam from 2005 to 2015. Methods Average incidence rabies (AIR) PEP rates for every 3 or 4 years (2005–2008, 2009–2012 and 2013–2015) were calculated to describe the spatial distribution of rabies PEP. Hotspot analysis was implemented to identify patterns of spatial significance using the Getis-Ord Gi statistic. For temporal pattern analysis, two regions [Mekong River Delta (MRD) and Southeast Central Coast (SCC)], with the highest incidence rates, and the seasonal-decomposition procedure based on loess (STL), were compared to assess their temporal patterns of rabies PEP. Findings We found hotspots in southern Vietnam and coldspots in northern Vietnam during the study period. Rabies cases were limited to specific areas. In addition, the hotspot analysis showed that new risk areas were identified in each period which were not observed in incidence rate maps. The seasonal plots showed seasonal patterns with a strong peak in February/July and a minor peak in October/December in the MRD region. However, in the SCC, a small peak was detected at the early part of each year and a strong peak in the middle of each year. Conclusion Our findings provide insight into understanding the geographical and seasonal patterns of rabies PEP in Vietnam. This study provides evidence to aid policy makers when making decisions and investing resources. Such information may also be utilized to raise public awareness to prevent rabies exposures and reduce unnecessary PEP. PMID:29634746

The Diesel Exhaust in Miners Study: II. Exposure monitoring surveys and development of exposure groups.

PubMed

Coble, Joseph B; Stewart, Patricia A; Vermeulen, Roel; Yereb, Daniel; Stanevich, Rebecca; Blair, Aaron; Silverman, Debra T; Attfield, Michael

2010-10-01

Air monitoring surveys were conducted between 1998 and 2001 at seven non-metal mining facilities to assess exposure to respirable elemental carbon (REC), a component of diesel exhaust (DE), for an epidemiologic study of miners exposed to DE. Personal exposure measurements were taken on workers in a cross-section of jobs located underground and on the surface. Air samples taken to measure REC were also analyzed for respirable organic carbon (ROC). Concurrent measurements to assess exposure to nitric oxide (NO) and nitrogen dioxide (NO₂), two gaseous components of DE, were also taken. The REC measurements were used to develop quantitative estimates of average exposure levels by facility, department, and job title for the epidemiologic analysis. Each underground job was assigned to one of three sets of exposure groups from specific to general: (i) standardized job titles, (ii) groups of standardized job titles combined based on the percentage of time in the major underground areas, and (iii) larger groups based on similar area carbon monoxide (CO) air concentrations. Surface jobs were categorized based on their use of diesel equipment and proximity to DE. A total of 779 full-shift personal measurements were taken underground. The average REC exposure levels for underground jobs with five or more measurements ranged from 31 to 58 μg m⁻³ at the facility with the lowest average exposure levels and from 313 to 488 μg m⁻³ at the facility with the highest average exposure levels. The average REC exposure levels for surface workers ranged from 2 to 6 μg m⁻³ across the seven facilities. There was much less contrast in the ROC compared with REC exposure levels measured between surface and underground workers within each facility, as well as across the facilities. The average ROC levels underground ranged from 64 to 195 μg m⁻³, while on the surface, the average ROC levels ranged from 38 to 71 μg m⁻³ by facility, an ∼2- to 3-fold difference. The average NO and NO₂ levels underground ranged from 0.20 to 1.49 parts per million (ppm) and from 0.10 to 0.60 ppm, respectively, and were ∼10 times higher than levels on the surface, which ranged from 0.02 to 0.11 ppm and from 0.01 to 0.06 ppm, respectively. The ROC, NO, and NO₂ concentrations underground were correlated with the REC levels (r = 0.62, 0.71, and 0.62, respectively). A total of 80% of the underground jobs were assigned an exposure estimate based on measurements taken for the specific job title or for other jobs with a similar percentage of time spent in the major underground work areas. The average REC exposure levels by facility were from 15 to 64 times higher underground than on the surface. The large contrast in exposure levels measured underground versus on the surface, along with the differences between the mining facilities and between underground jobs within the facilities resulted in a wide distribution in the exposure estimates for evaluation of exposure-response relationships in the epidemiologic analyses.

Possible Health Benefits From Reducing Occupational Magnetic Fields

PubMed Central

Bowman, Joseph D.; Ray, Tapas K.; Park, Robert M.

2015-01-01

Background Magnetic fields (MF) from AC electricity are a Possible Human Carcinogen, based on limited epidemiologic evidence from exposures far below occupational health limits. Methods To help formulate government guidance on occupational MF, the cancer cases prevented and the monetary benefits accruing to society by reducing workplace exposures were determined. Life-table methods produced Disability Adjusted Life Years, which were converted to monetary values. Results Adjusted for probabilities of causality, the expected increase in a worker’s disability-free life are 0.04 year (2 weeks) from a 1 microtesla (μT) MF reduction in average worklife exposure, which is equivalent to $5,100/worker/μT in year 2010 U.S. dollars (95% confidence interval $1,000–$9,000/worker/μT). Where nine electrosteel workers had 13.8 μT exposures, for example, moving them to ambient MFs would provide $600,000 in benefits to society (uncertainty interval $0–$1,000,000). Conclusions When combined with the costs of controls, this analysis provides guidance for precautionary recommendations for managing occupational MF exposures. PMID:23129537

Possible health benefits from reducing occupational magnetic fields.

PubMed

Bowman, Joseph D; Ray, Tapas K; Park, Robert M

2013-07-01

Magnetic fields (MF) from AC electricity are a Possible Human Carcinogen, based on limited epidemiologic evidence from exposures far below occupational health limits. To help formulate government guidance on occupational MF, the cancer cases prevented and the monetary benefits accruing to society by reducing workplace exposures were determined. Life-table methods produced Disability Adjusted Life Years, which were converted to monetary values. Adjusted for probabilities of causality, the expected increase in a worker's disability-free life are 0.04 year (2 weeks) from a 1 microtesla (µT) MF reduction in average worklife exposure, which is equivalent to $5,100/worker/µT in year 2010 U.S. dollars (95% confidence interval $1,000-$9,000/worker/µT). Where nine electrosteel workers had 13.8 µT exposures, for example, moving them to ambient MFs would provide $600,000 in benefits to society (uncertainty interval $0-$1,000,000). When combined with the costs of controls, this analysis provides guidance for precautionary recommendations for managing occupational MF exposures. Copyright © 2012 Wiley Periodicals, Inc.

Drinking water as a proportion of total human exposure to volatile N-nitrosamines.

PubMed

Hrudey, Steve E; Bull, Richard J; Cotruvo, Joseph A; Paoli, Greg; Wilson, Margaret

2013-12-01

Some volatile N-nitrosamines, primarily N-nitrosodimethylamine (NDMA), are recognized as products of drinking water treatment at ng/L levels and as known carcinogens. The U.S. EPA has identified the N-nitrosamines as contaminants being considered for regulation as a group under the Safe Drinking Water Act. Nitrosamines are common dietary components, and a major database (over 18,000 drinking water samples) has recently been created under the Unregulated Contaminant Monitoring Rule. A Monte Carlo modeling analysis in 2007 found that drinking water contributed less than 2.8% of ingested NDMA and less than 0.02% of total NDMA exposure when estimated endogenous formation was considered. Our analysis, based upon human blood concentrations, indicates that endogenous NDMA production is larger than expected. The blood-based estimates are within the range that would be calculated from estimates based on daily urinary NDMA excretion and an estimate based on methylated guanine in DNA of lymphocytes from human volunteers. Our analysis of ingested NDMA from food and water based on Monte Carlo modeling with more complete data input shows that drinking water contributes a mean proportion of the lifetime average daily NDMA dose ranging from between 0.0002% and 0.001% for surface water systems using free chlorine or between 0.001% and 0.01% for surface water systems using chloramines. The proportions of average daily dose are higher for infants (zero to six months) than other age cohorts, with the highest mean up to 0.09% (upper 95th percentile of 0.3%). © 2013 Society for Risk Analysis.

Documenting the kinetic time course of lambda-cyhalothrin metabolites in orally exposed volunteers for the interpretation of biomonitoring data.

PubMed

Khemiri, Rania; Côté, Jonathan; Fetoui, Hamadi; Bouchard, Michèle

2017-07-05

Lambda-cyhalothrin is a pyrethroid pesticide largely used in agriculture. Exposure assessment can be performed by measuring key urinary metabolites. For a proper use of biomonitoring data, it is however important to gain information on the toxicokinetics of these key biomarkers of exposure. A human volunteer study was performed to document the plasma and urinary time courses of major lambda-cyhalothrin metabolites. Seven volunteers ingested 0.025mgkg -1 body weight of lambda-cyhalothrin. Blood samples were withdrawn prior to dosing and at fixed time periods over the 72 h-period following ingestion and complete urine voids were collected pre-exposure and at pre-established intervals over 84h post-dosing. The cis-3-(2-chloro-3,3,3-trifluoroprop-1-en-1-yl)-2,2-dimethylcyclopropanecarboxylic acid (CFMP) and 3-phenoxybenzoic acid (3-PBA) metabolites were quantified in these samples. Plasma concentrations of CFMP and 3-PBA increased rapidly after ingestion, with average peak values at 3.1 and 4.0h post-dosing, respectively; subsequent elimination phase showed a rapid decay with a mean half-life (t ½ ) of ≈5.3 and 6.4h for CFMP and 3-PBA, respectively. Urinary rate time courses displayed a profile similar to the plasma concentration-time curves with corresponding mean t ½ of ≈4.2 and 5.9h. In the 84-h period post-treatment, on average 21% of lambda-cyhalothrin dose were excreted in urine as CFMP as compared to 30% as 3-PBA. Overall, CFMP and 3-PBA metabolites were confirmed to be major metabolites of lambda-cyhalothrin and exhibited similar kinetics with short half-lives; they thus both appear as useful biomarkers of exposure to lambda-cyhalothrin in humans. Copyright © 2017 Elsevier B.V. All rights reserved.

Quantitative ecological risk assessment of inhabitants exposed to polycyclic aromatic hydrocarbons in terrestrial soils of King George Island, Antarctica

NASA Astrophysics Data System (ADS)

Pongpiachan, S.; Hattayanone, M.; Pinyakong, O.; Viyakarn, V.; Chavanich, S. A.; Bo, C.; Khumsup, C.; Kittikoon, I.; Hirunyatrakul, P.

2017-03-01

This study aims to conduct a quantitative ecological risk assessment of human exposure to polycyclic aromatic hydrocarbons (PAHs) in terrestrial soils of King George Island, Antarctica. Generally, the average PAH concentrations detected in King George Terrestrial Soils (KGS) were appreciably lower than those of World Marine Sediments (WMS) and World Terrestrial Soils (WTS), highlighting the fact that Antarctica is one of the most pristine continents in the world. The total concentrations of twelve probably carcinogenic PAHs (ΣPAHs: a sum of Phe, An, Fluo, Pyr, B[a]A, Chry, B[b]F, B[k]F, B[a]P, Ind, D[a,h]A and B[g,h,i]P) were 3.21 ± 1.62 ng g-1, 5749 ± 4576 ng g-1, and 257,496 ± 291,268 ng g-1, for KGS, WMS and WTS, respectively. In spite of the fact that KGS has extremely low ΣPAHs in comparison with others, the percentage contribution of Phe is exceedingly high with the value of 50%. By assuming that incidental ingestion and dermal contact are two major exposure pathways responsible for the adverse human health effects, the cancer and non-cancer risks from environmental exposure to PAHs were carefully evaluated based on the ;Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions; memorandum provided by US-EPA. The logarithms of cancer risk levels of PAH contents in KGS varied from -11.1 to -7.18 with an average of -7.96 ± 7.73, which is 1790 times and 80,176 times lower than that of WMS and WTS, respectively. All cancer risk levels of PAH concentrations observed in KGS are significantly (p < 0.001) lower than those of WMS and WTS. Despite the Comandante Ferraz Antarctic Station fire occurred in February 25th, 2012, both the cancer and non-cancer risks of environmental exposure to PAHs were found in ;acceptable level;.

The effect of increase in dielectric values on specific absorption rate (SAR) in eye and head tissues following 900, 1800 and 2450 MHz radio frequency (RF) exposure

NASA Astrophysics Data System (ADS)

Keshvari, Jafar; Keshvari, Rahim; Lang, Sakari

2006-03-01

Numerous studies have attempted to address the question of the RF energy absorption difference between children and adults using computational methods. They have assumed the same dielectric parameters for child and adult head models in SAR calculations. This has been criticized by many researchers who have stated that child organs are not fully developed, their anatomy is different and also their tissue composition is slightly different with higher water content. Higher water content would affect dielectric values, which in turn would have an effect on RF energy absorption. The objective of this study was to investigate possible variation in specific absorption rate (SAR) in the head region of children and adults by applying the finite-difference time-domain (FDTD) method and using anatomically correct child and adult head models. In the calculations, the conductivity and permittivity of all tissues were increased from 5 to 20% but using otherwise the same exposure conditions. A half-wave dipole antenna was used as an exposure source to minimize the uncertainties of the positioning of a real mobile device and making the simulations easily replicable. Common mobile telephony frequencies of 900, 1800 and 2450 MHz were used in this study. The exposures of ear and eye regions were investigated. The SARs of models with increased dielectric values were compared to the SARs of the models where dielectric values were unchanged. The analyses suggest that increasing the value of dielectric parameters does not necessarily mean that volume-averaged SAR would increase. Under many exposure conditions, specifically at higher frequencies in eye exposure, volume-averaged SAR decreases. An increase of up to 20% in dielectric conductivity or both conductivity and permittivity always caused a SAR variation of less than 20%, usually about 5%, when it was averaged over 1, 5 or 10 g of cubic mass for all models. The thickness and composition of different tissue layers in the exposed regions within the human head play a more significant role in SAR variation compared to the variations (5-20%) of the tissue dielectric parameters.

Health impact assessment and monetary valuation of IQ loss in pre-school children due to lead exposure through locally produced food.

PubMed

Bierkens, J; Buekers, J; Van Holderbeke, M; Torfs, R

2012-01-01

A case study has been performed which involved the full chain assessment from policy drivers to health effect quantification of lead exposure through locally produced food on loss of IQ in pre-school children at the population level across the EU-27, including monetary valuation of the estimated health impact. Main policy scenarios cover the period from 2000 to 2020 and include the most important Community policy developments expected to affect the environmental release of lead (Pb) and corresponding human exposure patterns. Three distinct scenarios were explored: the emission situation based on 2000 data, a business-as-usual scenario (BAU) up to 2010 and 2020 and a scenario incorporating the most likely technological change expected (Most Feasible Technical Reductions, MFTR) in response to current and future legislation. Consecutive model calculations (MSCE-HM, WATSON, XtraFOOD, IEUBK) were performed by different partners on the project as part of the full chain approach to derive estimates of blood lead (B-Pb) levels in children as a consequence of the consumption of local produce. The estimated B-Pb levels were translated into an average loss of IQ points/child using an empirical relationship based on a meta-analysis performed by Schwartz (1994). The calculated losses in IQ points were subsequently further translated into the average cost/child using a cost estimate of €10.000 per loss of IQ point based on data from a literature review. The estimated average reduction of cost/child (%) for all countries considered in 2010 under BAU and MFTR are 12.16 and 18.08% as compared to base line conditions, respectively. In 2020 the percentages amount to 20.19 and 23.39%. The case study provides an example of the full-chain impact pathway approach taking into account all foreseeable pathways both for assessing the environmental fate and the associated human exposure and the mode of toxic action to arrive at quantitative estimates of health impacts at the individual and the population risk levels alike at EU scale. As the estimated B-Pb levels fall below the range of observed biomonitoring data collected for pre-school children in 6 different EU countries, results presented in this paper are only a first approximation of the costs entailed in the health effects of exposure to lead and the potential benefits that may arise from MFTR measures inscribed in Commission policies. Copyright © 2011 Elsevier B.V. All rights reserved.

Are occupational exposure limits becoming more alike within the European Union?

PubMed

Schenk, Linda; Hansson, Sven Ove; Rudén, Christina; Gilek, Michael

2008-10-01

The occupational exposure limits (OELs) established by seven different national regulatory agencies of EU member states are compared with those of the European Commission (EC). The comparison concerned: (1) what chemicals have been selected, (2) the average level of exposure limits for all chemicals, and (3) the similarity between the OELs of different EU member states and the OELs recommended by the European Commission. The average level of the exposure limits has declined during the past 10 years in four of the five countries in our study for which historical data were available to us. Poland has not changed its level noticeably and Germany has increased it. Since the first list of indicative OELs was established by the EC, a few of the EU exposure limits have been lowered. The similarity index indicates that the exposure limits of EU member states are converging towards the European Commission's recommended OELs. Still, the average level of OELs differs between organizations--the Estonian OELs are on average 35% higher than the Polish OELs.

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

PubMed

Joseph, Wout; Verloock, Leen

2010-11-01

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

Rabies in the Americas: 1998-2014

PubMed Central

Vigilato, Marco A. N.; Pompei, Julio A.; Rocha, Felipe; Vokaty, Alexandra; Molina-Flores, Baldomero; Cosivi, Ottorino; Del Rio Vilas, Victor J.

2018-01-01

Through national efforts and regional cooperation under the umbrella of the Regional Program for the Elimination of Rabies, dog and human rabies have decreased significantly in Latin America and Caribbean (LAC) countries over the last three decades. To achieve this decline, LAC countries had to develop national plans, and consolidate capabilities such as regular mass dog vaccination, opportune post-exposure prophylaxis and sensitive surveillance. This paper presents longitudinal data for 21 LAC countries on dog vaccination, PEP and rabies surveillance collected from the biannual regional meeting for rabies directors from 1998–2014 and from the Regional Epidemiologic Surveillance System for Rabies (SIRVERA). Differences in human and dog rabies incidence rates and dog vaccination rates were shown between low, middle and high-income countries. At the peak, over 50 million dogs were vaccinated annually in national campaigns in the countries represented. The reported number of animal exposures remained fairly stable during the study period with an incidence rate ranging from 123 to 191 reported exposures per 100,000 people. On average, over 2 million doses of human vaccine were applied annually. In the most recent survey, only 37% of countries reported that they had sufficient financial resources to meet the program objectives. The data show a sufficient and sustained effort of the LAC countries in the area of dog vaccination and provide understanding of the baseline effort required to reduce dog-mediated rabies incidence. PMID:29558465

Rabies in the Americas: 1998-2014.

PubMed

Freire de Carvalho, Mary; Vigilato, Marco A N; Pompei, Julio A; Rocha, Felipe; Vokaty, Alexandra; Molina-Flores, Baldomero; Cosivi, Ottorino; Del Rio Vilas, Victor J

2018-03-01

Through national efforts and regional cooperation under the umbrella of the Regional Program for the Elimination of Rabies, dog and human rabies have decreased significantly in Latin America and Caribbean (LAC) countries over the last three decades. To achieve this decline, LAC countries had to develop national plans, and consolidate capabilities such as regular mass dog vaccination, opportune post-exposure prophylaxis and sensitive surveillance. This paper presents longitudinal data for 21 LAC countries on dog vaccination, PEP and rabies surveillance collected from the biannual regional meeting for rabies directors from 1998-2014 and from the Regional Epidemiologic Surveillance System for Rabies (SIRVERA). Differences in human and dog rabies incidence rates and dog vaccination rates were shown between low, middle and high-income countries. At the peak, over 50 million dogs were vaccinated annually in national campaigns in the countries represented. The reported number of animal exposures remained fairly stable during the study period with an incidence rate ranging from 123 to 191 reported exposures per 100,000 people. On average, over 2 million doses of human vaccine were applied annually. In the most recent survey, only 37% of countries reported that they had sufficient financial resources to meet the program objectives. The data show a sufficient and sustained effort of the LAC countries in the area of dog vaccination and provide understanding of the baseline effort required to reduce dog-mediated rabies incidence.

Probabilistic Model for Laser Damage to the Human Retina

DTIC Science & Technology

2012-03-01

the beam. Power density may be measured in radiant exposure, J cm2 , or by irradiance , W cm2 . In the experimental database used in this study and...to quan- tify a binary response, either lethal or non-lethal, within a population such as insects or rats. In directed energy research, probit...value of the normalized Arrhenius damage integral. In a one-dimensional simulation, the source term is determined as a spatially averaged irradiance (W

Microenvironmental characteristics important for personal exposures to aldehydes in Sacramento, CA, and Milwaukee, WI

NASA Astrophysics Data System (ADS)

Raymer, J. H.; Akland, G.; Johnson, T. R.; Long, T.; Michael, L.; Cauble, L.; McCombs, M.

Oxygenated additives in gasoline are designed to decrease the ozone-forming hydrocarbons and total air toxics, yet they can increase the emissions of aldehydes and thus increase human exposure to these toxic compounds. This paper describes a study conducted to characterize targeted aldehydes in microenvironments in Sacramento, CA, and Milwaukee, WI, and to improve our understanding of the impact of the urban environment on human exposure to air toxics. Data were obtained from microenvironmental concentration measurements, integrated, 24-h personal measurements, indoor and outdoor pollutant monitors at the participants' residences, from ambient pollutant monitors at fixed-site locations in each city, and from real-time diaries and questionnaires completed by the technicians and participants. As part of this study, a model to predict personal exposures based on individual time/activity data was developed for comparison to measured concentrations. Predicted concentrations were generally within 25% of the measured concentrations. The microenvironments that people encounter daily provide for widely varying exposures to aldehydes. The activities that occur in those microenvironments can modulate the aldehyde concentrations dramatically, especially for environments such as "indoor at home." By considering personal activity, location (microenvironment), duration in the microenvironment, and a knowledge of the general concentrations of aldehydes in the various microenvironments, a simple model can do a reasonably good job of predicting the time-averaged personal exposures to aldehydes, even in the absence of monitoring data. Although concentrations of aldehydes measured indoors at the participants' homes tracked well with personal exposure, there were instances where personal exposures and indoor concentrations differed significantly. Key to the ability to predict exposure based on time/activity data is the quality and completeness of the microenvironmental characterizations for the chemicals of interest. Consistent with many earlier studies, personal exposures are difficult to predict using data from regional outdoor monitors.

The influence of high intensity terahertz radiation on mammalian cell adhesion, proliferation and differentiation.

PubMed

Williams, Rachel; Schofield, Amy; Holder, Gareth; Downes, Joan; Edgar, David; Harrison, Paul; Siggel-King, Michele; Surman, Mark; Dunning, David; Hill, Stephen; Holder, David; Jackson, Frank; Jones, James; McKenzie, Julian; Saveliev, Yuri; Thomsen, Neil; Williams, Peter; Weightman, Peter

2013-01-21

Understanding the influence of exposure of biological systems to THz radiation is becoming increasingly important. There is some evidence to suggest that THz radiation can influence important activities within mammalian cells. This study evaluated the influence of the high peak power, low average power THz radiation produced by the ALICE (Daresbury Laboratory, UK) synchrotron source on human epithelial and embryonic stem cells. The cells were maintained under standard tissue culture conditions, during which the THz radiation was delivered directly into the incubator for various exposure times. The influence of the THz radiation on cell morphology, attachment, proliferation and differentiation was evaluated. The study demonstrated that there was no difference in any of these parameters between irradiated and control cell cultures. It is suggested that under these conditions the cells are capable of compensating for any effects caused by exposure to THz radiation with the peak powers levels employed in these studies.

Absence of acute ocular damage in humans after prolonged exposure to intense RF EMF

NASA Astrophysics Data System (ADS)

Adibzadeh, F.; van Rhoon, G. C.; Verduijn, G. M.; Naus-Postema, N. C.; Paulides, M. M.

2016-01-01

The eye is considered to be a critical organ when determining safety standards for radio frequency (RF) radiation. Experimental data obtained using animals showed that RF heating of the eye, particularly over a specific threshold, can induce cataracts. During the treatment of cancer in the head and neck by hyperthermia, the eyes receive a considerable dose of RF radiation due to stray radiation from the prolonged (60 min) and intense exposure at 434 MHz of this region. In the current study, we verified the exposure guidelines for humans by determining the association between the electromagnetic and thermal dose in the eyes with the reported ocular effects. We performed a simulation study to retrospectively assess the specific absorption rate (SAR) and temperature increase in the eyes of 16 selected patients (encompassing a total of 74 treatment sessions) whose treatment involved high power delivery as well as a minimal distance between the tumor site and the eye. Our results show that the basic restrictions on the peak 10 g spatial-averaged SAR (10 W kg-1) and peak tissue temperature increase (1 °C) are exceeded by up to 10.4 and 4.6 times, on average, and by at least 6.2 and 1.8 times when considering the lower limit of the 95% confidence interval. Evaluation of the acute effects according to patients’ feedback (all patients), the common toxicity criteria scores (all patients) and an ophthalmology investigation (one patient with the highest exposure) revealed no indication of any serious acute ocular effect, even though the eyes were exposed to high electromagnetic fields, leading to a high thermal dose. We also found that, although there is a strong correlation (R 2  =  0.88) between the predicted induced SAR and temperature in the eye, there are large uncertainties regarding the temperature-SAR relationship. Given this large uncertainty (129%) compared with the uncertainty of 3D temperature simulations (61%), we recommend using temperature simulations as a dosimetric measure in electromagnetic exposure risk assessments.

The Diesel Exhaust in Miners Study: II. Exposure Monitoring Surveys and Development of Exposure Groups

PubMed Central

Coble, Joseph B.; Stewart, Patricia A.; Vermeulen, Roel; Yereb, Daniel; Stanevich, Rebecca; Blair, Aaron; Silverman, Debra T.; Attfield, Michael

2010-01-01

Air monitoring surveys were conducted between 1998 and 2001 at seven non-metal mining facilities to assess exposure to respirable elemental carbon (REC), a component of diesel exhaust (DE), for an epidemiologic study of miners exposed to DE. Personal exposure measurements were taken on workers in a cross-section of jobs located underground and on the surface. Air samples taken to measure REC were also analyzed for respirable organic carbon (ROC). Concurrent measurements to assess exposure to nitric oxide (NO) and nitrogen dioxide (NO2), two gaseous components of DE, were also taken. The REC measurements were used to develop quantitative estimates of average exposure levels by facility, department, and job title for the epidemiologic analysis. Each underground job was assigned to one of three sets of exposure groups from specific to general: (i) standardized job titles, (ii) groups of standardized job titles combined based on the percentage of time in the major underground areas, and (iii) larger groups based on similar area carbon monoxide (CO) air concentrations. Surface jobs were categorized based on their use of diesel equipment and proximity to DE. A total of 779 full-shift personal measurements were taken underground. The average REC exposure levels for underground jobs with five or more measurements ranged from 31 to 58 μg m−3 at the facility with the lowest average exposure levels and from 313 to 488 μg m−3 at the facility with the highest average exposure levels. The average REC exposure levels for surface workers ranged from 2 to 6 μg m−3 across the seven facilities. There was much less contrast in the ROC compared with REC exposure levels measured between surface and underground workers within each facility, as well as across the facilities. The average ROC levels underground ranged from 64 to 195 μg m−3, while on the surface, the average ROC levels ranged from 38 to 71 μg m−3 by facility, an ∼2- to 3-fold difference. The average NO and NO2 levels underground ranged from 0.20 to 1.49 parts per million (ppm) and from 0.10 to 0.60 ppm, respectively, and were ∼10 times higher than levels on the surface, which ranged from 0.02 to 0.11 ppm and from 0.01 to 0.06 ppm, respectively. The ROC, NO, and NO2 concentrations underground were correlated with the REC levels (r = 0.62, 0.71, and 0.62, respectively). A total of 80% of the underground jobs were assigned an exposure estimate based on measurements taken for the specific job title or for other jobs with a similar percentage of time spent in the major underground work areas. The average REC exposure levels by facility were from 15 to 64 times higher underground than on the surface. The large contrast in exposure levels measured underground versus on the surface, along with the differences between the mining facilities and between underground jobs within the facilities resulted in a wide distribution in the exposure estimates for evaluation of exposure–response relationships in the epidemiologic analyses. PMID:20876232

Sense of presence and anxiety during virtual social interactions between a human and virtual humans.

PubMed

Morina, Nexhmedin; Brinkman, Willem-Paul; Hartanto, Dwi; Emmelkamp, Paul M G

2014-01-01

Virtual reality exposure therapy (VRET) has been shown to be effective in treatment of anxiety disorders. Yet, there is lack of research on the extent to which interaction between the individual and virtual humans can be successfully implanted to increase levels of anxiety for therapeutic purposes. This proof-of-concept pilot study aimed at examining levels of the sense of presence and anxiety during exposure to virtual environments involving social interaction with virtual humans and using different virtual reality displays. A non-clinical sample of 38 participants was randomly assigned to either a head-mounted display (HMD) with motion tracker and sterescopic view condition or a one-screen projection-based virtual reality display condition. Participants in both conditions engaged in free speech dialogues with virtual humans controlled by research assistants. It was hypothesized that exposure to virtual social interactions will elicit moderate levels of sense of presence and anxiety in both groups. Further it was expected that participants in the HMD condition will report higher scores of sense of presence and anxiety than participants in the one-screen projection-based display condition. Results revealed that in both conditions virtual social interactions were associated with moderate levels of sense of presence and anxiety. Additionally, participants in the HMD condition reported significantly higher levels of presence than those in the one-screen projection-based display condition (p = .001). However, contrary to the expectations neither the average level of anxiety nor the highest level of anxiety during exposure to social virtual environments differed between the groups (p = .97 and p = .75, respectively). The findings suggest that virtual social interactions can be successfully applied in VRET to enhance sense of presence and anxiety. Furthermore, our results indicate that one-screen projection-based displays can successfully activate levels of anxiety in social virtual environments. The outcome can prove helpful in using low-cost projection-based virtual reality environments for treating individuals with social phobia.

Increased sensitivity of the non-human primate eye to microwave radiation following ophthalmic drug pretreatment.

PubMed

Kues, H A; Monahan, J C; D'Anna, S A; McLeod, D S; Lutty, G A; Koslov, S

1992-01-01

Previous studies in our laboratory have established that pulsed microwaves at 2.45 GHz and 10 mW/cm2 are associated with production of corneal endothelial lesions and with disruption of the blood-aqueous barrier in the non-human primate eye. In the study reported here we examined ocular damage in monkeys (M. mulatta and M. fascicularis) following topical treatment with one of two ophthalmic drugs (timolol maleate and pilocarpine) that preceded exposure to pulsed microwaves. Anesthetized monkeys were sham exposed or exposed to pulsed, 2.45 GHz microwaves (10 microseconds, 100 pps) at average power densities of 0.2, 1, 5, 10, or 15 mW/cm2 4 h a day for 3 consecutive days (respective SARs were 0.052, 0.26, 1.3, 2.6, and 3.9 W/kg). Immediately before microwave exposure, one or both eyes were treated topically with one drop of 0.5% timolol maleate or of 2% pilocarpine. Following administration of a drug, we observed a significant reduction in the power-density threshold (from 10 to 1 mW/cm2) for induction of corneal endothelial lesions and for increased vascular permeability of the iris. Diagnostic procedures (in vivo specular microscopy and fluorescein iris angiography) were performed following each exposure protocol. In addition, increased vascular permeability was confirmed with horseradish peroxidase tracer techniques. Although we did not measure intraocular temperatures in experimental animals, the results suggest that a mechanism other than significant heating of the eye is involved. Our data indicate that pulsed microwaves at an average SAR of 0.26 W/kg, if administered after pretreatment with ophthalmic drugs, can produce significant ocular effects in the anesthetized primate.

Maternal urinary bisphenol a during pregnancy and maternal and neonatal thyroid function in the CHAMACOS study.

PubMed

Chevrier, Jonathan; Gunier, Robert B; Bradman, Asa; Holland, Nina T; Calafat, Antonia M; Eskenazi, Brenda; Harley, Kim G

2013-01-01

Bisphenol A (BPA) is widely used in the manufacture of polycarbonate plastic bottles, food and beverage can linings, thermal receipts, and dental sealants. Animal and human studies suggest that BPA may disrupt thyroid function. Although thyroid hormones play a determinant role in human growth and brain development, no studies have investigated relations between BPA exposure and thyroid function in pregnant women or neonates. Our goal was to evaluate whether exposure to BPA during pregnancy is related to thyroid hormone levels in pregnant women and neonates. We measured BPA concentration in urine samples collected during the first and second half of pregnancy in 476 women participating in the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. We also measured free thyroxine (T4), total T4, and thyroid-stimulating hormone (TSH) in women during pregnancy, and TSH in neonates. Associations between the average of the two BPA measurements and maternal thyroid hormone levels were not statistically significant. Of the two BPA measurements, only the one taken closest in time to the TH measurement was significantly associated with a reduction in total T4 (β = -0.13 µg/dL per log2 unit; 95% CI: -0.25, 0.00). The average of the maternal BPA concentrations was associated with reduced TSH in boys (-9.9% per log2 unit; 95% CI: -15.9%, -3.5%) but not in girls. Among boys, the relation was stronger when BPA was measured in the third trimester of pregnancy and decreased with time between BPA and TH measurements. Results suggest that exposure to BPA during pregnancy is related to reduced total T4 in pregnant women and decreased TSH in male neonates. Findings may have implications for fetal and neonatal development.

Novel brominated flame retardants in food composites and human milk from the Chinese Total Diet Study in 2011: Concentrations and a dietary exposure assessment.

PubMed

Shi, Zhixiong; Zhang, Lei; Li, Jingguang; Zhao, Yunfeng; Sun, Zhiwei; Zhou, Xianqing; Wu, Yongning

2016-11-01

On the basis of the fifth Chinese total diet study (TDS) performed in 2011, the dietary exposure of the Chinese population to novel brominated flame retardants (NBFRs) was assessed. Six NBFRs were determined in 80 composite samples from four animal origin food groups and 29 pooled human milk samples. Based on gas chromatography-negative chemical ionization mass spectrometry (GC-NCI/MS) analysis, the levels of the total NBFRs ranged from

Modeling personal particle-bound polycyclic aromatic hydrocarbon (pb-pah) exposure in human subjects in Southern California.

PubMed

Wu, Jun; Tjoa, Thomas; Li, Lianfa; Jaimes, Guillermo; Delfino, Ralph J

2012-07-11

Exposure to polycyclic aromatic hydrocarbon (PAH) has been linked to various adverse health outcomes. Personal PAH exposures are usually measured by personal monitoring or biomarkers, which are costly and impractical for a large population. Modeling is a cost-effective alternative to characterize personal PAH exposure although challenges exist because the PAH exposure can be highly variable between locations and individuals in non-occupational settings. In this study we developed models to estimate personal inhalation exposures to particle-bound PAH (PB-PAH) using data from global positioning system (GPS) time-activity tracking data, traffic activity, and questionnaire information. We conducted real-time (1-min interval) personal PB-PAH exposure sampling coupled with GPS tracking in 28 non-smoking women for one to three sessions and one to nine days each session from August 2009 to November 2010 in Los Angeles and Orange Counties, California. Each subject filled out a baseline questionnaire and environmental and behavior questionnaires on their typical activities in the previous three months. A validated model was used to classify major time-activity patterns (indoor, in-vehicle, and other) based on the raw GPS data. Multiple-linear regression and mixed effect models were developed to estimate averaged daily and subject-level PB-PAH exposures. The covariates we examined included day of week and time of day, GPS-based time-activity and GPS speed, traffic- and roadway-related parameters, meteorological variables (i.e. temperature, wind speed, relative humidity), and socio-demographic variables and occupational exposures from the questionnaire. We measured personal PB-PAH exposures for 180 days with more than 6 h of valid data on each day. The adjusted R2 of the model was 0.58 for personal daily exposures, 0.61 for subject-level personal exposures, and 0.75 for subject-level micro-environmental exposures. The amount of time in vehicle (averaging 4.5% of total sampling time) explained 48% of the variance in daily personal PB-PAH exposure and 39% of the variance in subject-level exposure. The other major predictors of PB-PAH exposures included length-weighted traffic count, work-related exposures, and percent of weekday time. We successfully developed regression models to estimate PB-PAH exposures based on GPS-tracking data, traffic data, and simple questionnaire information. Time in vehicle was the most important determinant of personal PB-PAH exposure in this population. We demonstrated the importance of coupling real-time exposure measures with GPS time-activity tracking in personal air pollution exposure assessment.

Developmental and hematological responses to low level continuous exposure of nitrogen dioxide in mice

NASA Technical Reports Server (NTRS)

Singh, J.

1977-01-01

Young healthy mice were continuously exposed to 0ppm, 0.5ppm, 1.0ppm and 5ppm nitrogen dioxide gas for eight weeks. Nitrogen dioxide exposure for eight weeks decreased the average weight of mice, increased the average weight of lungs, heart, and brain and decreased the average weight of liver. Nitrogen dioxide exposure did not have any effects on the WBC and RBC in mice blood but it increased the HCT and HGB in mice blood. Nitrogen dioxide exposure increased the MCV and decreased the MCH and MCHC in mice blood.

Assessment and comparison of total RF-EMF exposure in femtocell and macrocell base station scenarios.

PubMed

Aerts, Sam; Plets, David; Verloock, Leen; Martens, Luc; Joseph, Wout

2014-12-01

The indoor coverage of a mobile service can be drastically improved by deployment of an indoor femtocell base station (FBS). However, the impact of its proximity on the total exposure of the human body to radio-frequency (RF) electromagnetic fields (EMFs) is unknown. Using a framework designed for the combination of near-field and far-field exposure, the authors assessed and compared the RF-EMF exposure of a mobile-phone (MP) user that is either connected to an FBS or a conventional macrocell base station while in an office environment. It is found that, in average macrocell coverage and MP use-time conditions and for Universal Mobile Telecommunications System technology, the total exposure can be reduced by a factor of 20-40 by using an FBS, mostly due to the significant decrease in the output power of the MP. In general, the framework presented in this study can be used for any exposure scenario, featuring any number of technologies, base stations and/or access points, users and duration. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

How do anthropogenic contaminants (ACs) affect behaviour? Multi-level analysis of the effects of copper on boldness in hermit crabs.

PubMed

White, Stephen J; Briffa, Mark

2017-02-01

Natural animal populations are increasingly exposed to human impacts on the environment, which could have consequences for their behaviour. Among these impacts is exposure to anthropogenic contaminants. Any environmental variable that influences internal state could impact behaviour across a number of levels: at the sample mean, at the level of among-individual differences in behaviour ('animal personality') and at the level of within-individual variation in behaviour (intra-individual variation, 'IIV'). Here we examined the effect of exposure to seawater-borne copper on the startle response behaviour of European hermit crabs, Pagurus bernhardus across these levels. Copper exposure rapidly led to longer startle responses on average, but did not lead to any change in repeatability indicating that individual differences were present and equally consistent in the presence and absence of copper. There was no strong evidence that copper exposure led to changes in IIV. Our data show that exposure to copper for 1 week produces sample mean level changes in the behaviour of hermit crabs. However, there is no evidence that this exposure led to changes in repeatability through feedback loops.

Neuropathological Consequences of Gestational Exposure to Concentrated Ambient Fine and Ultrafine Particles in the Mouse.

PubMed

Klocke, Carolyn; Allen, Joshua L; Sobolewski, Marissa; Mayer-Pröschel, Margot; Blum, Jason L; Lauterstein, Dana; Zelikoff, Judith T; Cory-Slechta, Deborah A

2017-04-01

Increasing evidence indicates that the central nervous system (CNS) is a target of air pollution. We previously reported that postnatal exposure of mice to concentrated ambient ultrafine particles (UFP; ≤100 nm) via the University of Rochester HUCAPS system during a critical developmental window of CNS development, equivalent to human 3rd trimester, produced male-predominant neuropathological and behavioral characteristics common to multiple neurodevelopmental disorders, including autism spectrum disorder (ASD), in humans. The current study sought to determine whether vulnerability to fine (≤2.5 μm) and UFP air pollution exposure extends to embryonic periods of brain development in mice, equivalent to human 1st and 2nd trimesters. Pregnant mice were exposed 6 h/day from gestational days (GDs) 0.5-16.5 using the New York University VACES system to concentrated ambient fine/ultrafine particles at an average concentration of 92.69 μg/m3 over the course of the exposure period. At postnatal days (PNDs) 11-15, neuropathological consequences were characterized. Gestational air pollution exposures produced ventriculomegaly, increased corpus callosum (CC) area and reduced hippocampal area in both sexes. Both sexes demonstrated CC hypermyelination and increased microglial activation and reduced total CC microglia number. Analyses of iron deposition as a critical component of myelination revealed increased iron deposition in the CC of exposed female offspring, but not in males. These findings demonstrate that vulnerability of the brain to air pollution extends to gestation and produces features of several neurodevelopmental disorders in both sexes. Further, they highlight the importance of the commonalities of components of particulate matter exposures as a source of neurotoxicity and common CNS alterations. © The Author 2017. Published by Oxford University Press on behalf of the Society of Toxicology. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

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

PubMed

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

2017-07-25

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

Waif goodbye! Average-size female models promote positive body image and appeal to consumers.

PubMed

Diedrichs, Phillippa C; Lee, Christina

2011-10-01

Despite consensus that exposure to media images of thin fashion models is associated with poor body image and disordered eating behaviours, few attempts have been made to enact change in the media. This study sought to investigate an effective alternative to current media imagery, by exploring the advertising effectiveness of average-size female fashion models, and their impact on the body image of both women and men. A sample of 171 women and 120 men were assigned to one of three advertisement conditions: no models, thin models and average-size models. Women and men rated average-size models as equally effective in advertisements as thin and no models. For women with average and high levels of internalisation of cultural beauty ideals, exposure to average-size female models was associated with a significantly more positive body image state in comparison to exposure to thin models and no models. For men reporting high levels of internalisation, exposure to average-size models was also associated with a more positive body image state in comparison to viewing thin models. These findings suggest that average-size female models can promote positive body image and appeal to consumers.

A comparison of a laboratory and field study of annoyance and acceptability of aircraft noise exposures. [human reactions and tolerance

NASA Technical Reports Server (NTRS)

Borsky, P. N.

1977-01-01

Residents living in close, middle and distant areas from JFK Airport were included in a field interview and laboratory study. Judgments were made of simulated aircraft noise exposures of comparable community indoor noise levels and mixes of aircraft. Each group of subjects judged the levels of noise typical for its distance area. Four different numbers of flyovers were tested: less than average for each area, the approximate average, the peak number, or worst day, and above peak number. The major findings are: (1) the reported integrated field annoyance is best related to the annoyance reported for the simulated approximate worst day exposure in the laboratory; (2) annoyance is generally less when there are fewer aircraft flyovers, and the subject has less fear of crashes and more favorable attitudes toward airplanes; (3) beliefs in harmful health effects and misfeasance by operators of aircraft are also highly correlated with fear and noise annoyance; (4) in direct retrospective comparisons of number of flights, noise levels and annoyance, subjects more often said the worst day laboratory exposured more like their usual home environments; and (5) subjects do not expect an annoyance-free environment. Half of the subjects can accept an annoyance level of 5 to 6 from a possible annoyance range of 0 to 9, 28% can live with an annoyance intensity of 7, and only 5% can accept the top scores of 8 to 9.

DEVELOMENT AND EVALUATION OF A MODEL FOR ESTIMATING LONG-TERM AVERAGE OZONE EXPOSURES TO CHILDREN

EPA Science Inventory

Long-term average exposures of school-age children can be modelled using longitudinal measurements collected during the Harvard Southern California Chronic Ozone Exposure Study over a 12-month period: June, 1995-May, 1996. The data base contains over 200 young children with perso...

Smoking in top-grossing movies--United States, 2010.

PubMed

2011-07-15

The National Cancer Institute has concluded that studies indicate a causal relationship between exposure to depictions of smoking in movies and youth smoking initiation. Adolescents in the top quartile of exposures to onscreen tobacco incidents have been found to be approximately twice as likely to begin smoking as those in the bottom quartile. The 2010 U.S. Department of Health and Human Services strategic plan to reduce tobacco use includes reducing youth exposure to onscreen smoking. To monitor tobacco use in movies, Thumbs Up! Thumbs Down! (TUTD), a project of Breathe California of Sacramento-Emigrant Trails, counts occurrences of tobacco incidents in U.S. top-grossing movies each year. This report updates a previous report with the latest TUTD findings. In 2010, the number of onscreen tobacco incidents in youth-rated (G, PG, or PG-13) movies continued a downward trend, decreasing 71.6% from 2,093 incidents in 2005 to 595 in 2010. Similarly, the average number of incidents per youth-rated movie decreased 66.2%, from 20.1 in 2005 to 6.8 in 2010. The degree of decline, however, varied substantially by motion picture company. The three companies with published policies designed to reduce tobacco use in their movies had an average decrease in tobacco incidents of 95.8%, compared with an average decrease of 41.7% among the three major motion picture companies and independents without policies. This finding indicates that an enforceable policy aimed at reducing tobacco use in youth-rated movies can lead to substantially fewer tobacco incidents in movies and help prevent adolescent initiation of smoking.

Assessment of asbestos exposure during a simulated agricultural activity in the proximity of the former asbestos mine of Balangero, Italy.

PubMed

Turci, Francesco; Favero-Longo, Sergio Enrico; Gazzano, Claudia; Tomatis, Maura; Gentile-Garofalo, Laura; Bergamini, Massimo

2016-05-05

The natural occurrence of asbestos (NOA) in rural areas is a serious concern for human health and the dispersion route of asbestos in the proximity of natural asbestos-rich settings has been marginally evaluated so far. NOA may affect air, but also water and soil quality. In rural areas population may be exposed to asbestos with a largely unknown impact on human health. This work investigates the potential exposure of a farmer cultivating a field nearby the largest former asbestos mine of Western Europe (Balangero, Italy). The concentration of waterborne asbestos in the stream used to water the field was measured (ca. 2×10(5) fibers per liter, ff/L) and the cultivated ultramafic topsoil characterized, evidencing a remarkable occurrence of chrysotile. The worker's personal exposure and the environmental fiber dispersion during a simulated agricultural activity (tillage) were quantified in two independent trials. During the trials, the worker was exposed to average concentrations of 16 and 26 ff/L, with a peak of 40 ff/L. These data inform about the possible exposure of an agricultural worker to asbestos concentration higher than the accepted threshold of 2 ff/L. The release of asbestos fibers into the environment was negligible (0-2 ff/L). Copyright © 2016 Elsevier B.V. All rights reserved.

The Burden of Rabies in Tanzania and Its Impact on Local Communities

PubMed Central

Sambo, Maganga; Cleaveland, Sarah; Ferguson, Heather; Lembo, Tiziana; Simon, Cleophas; Urassa, Honorati; Hampson, Katie

2013-01-01

Background Rabies remains a major public health threat in many parts of the world and is responsible for an estimated 55,000 human deaths annually. The burden of rabies is estimated to be around US$20 million in Africa, with the highest financial expenditure being the cost of post-exposure prophylaxis (PEP). However, these calculations may be substantial underestimates because the costs to households of coping with endemic rabies have not been investigated. We therefore aimed to estimate the household costs, health-seeking behaviour, coping strategies, and outcomes of exposure to rabies in rural and urban communities in Tanzania. Methods and Findings Extensive investigative interviews were used to estimate the incidence of human deaths and bite exposures. Questionnaires with bite victims and their families were used to investigate health-seeking behaviour and costs (medical and non-medical costs) associated with exposure to rabies. We calculated that an average patient in rural Tanzania, where most people live on less than US$1 per day, would need to spend over US$100 to complete WHO recommended PEP schedules. High costs and frequent shortages of PEP led to poor compliance with PEP regimens, delays in presentation to health facilities, and increased risk of death. Conclusion The true costs of obtaining PEP were twice as high as those previously reported from Africa and should be considered in re-evaluations of the burden of rabies. PMID:24244767

Commuter exposure to ultrafine particles in different urban locations, transportation modes and routes

NASA Astrophysics Data System (ADS)

Ragettli, Martina S.; Corradi, Elisabetta; Braun-Fahrländer, Charlotte; Schindler, Christian; de Nazelle, Audrey; Jerrett, Michael; Ducret-Stich, Regina E.; Künzli, Nino; Phuleria, Harish C.

2013-10-01

A better understanding of ultrafine particle (UFP) exposure in different urban transport microenvironments is important for epidemiological exposure assessments and for policy making. Three sub-studies were performed to characterize personal exposure to UFP concentration and average particle size distribution diameters in frequently traveled commuter microenvironments in the city of Basel, Switzerland. First, the spatial variation of sidewalk UFP exposures within urban areas and transport-specific microenvironments was explored. Second, exposure to UFP concentration and average particle size were quantified for five modes of transportation (walking, bicycle, bus, tram, car) during different times of the day and week, along the same route. Finally, the contribution of bicycle commuting along two different routes (along main roads, away from main roads) to total daily exposures was assessed by 24-h personal measurements. In general, smaller average particle sizes and higher UFP levels were measured at places and for travel modes in close proximity to traffic. Average trip UFP concentrations were higher in car (31,784 particles cm-³) and on bicycle (22,660 particles cm-³) compared to walking (19,481 particles cm-³) and public transportation (14,055-18,818 particles cm-³). Concentrations were highest for all travel modes during weekday morning rush hours, compared to other time periods. UFP concentration was lowest in bus, regardless of time period. Bicycle travel along main streets between home and work place (24 min on average) contributed 21% and 5% to total daily UFP exposure in winter and summer, respectively. Contribution of bicycle commutes to total daily UFP exposure could be reduced by half if main roads are avoided. Our results show the importance of considering commuter behavior and route choice in exposure assessment studies.

Time allocation shifts and pollutant exposure due to traffic congestion: an analysis using the national human activity pattern survey.

PubMed

Zhang, Kai; Batterman, Stuart A

2009-10-15

Traffic congestion increases air pollutant exposures of commuters and urban populations due to the increased time spent in traffic and the increased vehicular emissions that occur in congestion, especially "stop-and-go" traffic. Increased time in traffic also decreases time in other microenvironments, a trade-off that has not been considered in previous time activity pattern (TAP) analyses conducted for exposure assessment purposes. This research investigates changes in time allocations and exposures that result from traffic congestion. Time shifts were derived using data from the National Human Activity Pattern Survey (NHAPS), which was aggregated to nine microenvironments (six indoor locations, two outdoor locations and one transport location). After imputing missing values, handling outliers, and conducting other quality checks, these data were stratified by respondent age, employment status and period (weekday/weekend). Trade-offs or time-shift coefficients between time spent in vehicles and the eight other microenvironments were then estimated using robust regression. For children and retirees, congestion primarily reduced the time spent at home; for older children and working adults, congestion shifted the time spent at home as well as time in schools, public buildings, and other indoor environments. Changes in benzene and PM(2.5) exposure were estimated for the current average travel delay in the U.S. (9 min day(-1)) and other scenarios using the estimated time shifts coefficients, concentrations in key microenvironments derived from the literature, and a probabilistic analysis. Changes in exposures depended on the duration of the congestion and the pollutant. For example, a 30 min day(-1) travel delay was determined to account for 21+/-12% of current exposure to benzene and 14+/-8% of PM(2.5) exposure. The time allocation shifts and the dynamic approach to TAPs improve estimates of exposure impacts from congestion and other recurring events.

[Effects of rare earth compounds on human peripheral mononuclear cell telomerase and apoptosis].

PubMed

Yu, Li; Dai, Yu-Cheng; Yuan, Zhao-Kang; Li, Jie

2004-07-01

To study the effects of rare earth exposure on human telomerase and apoptosis of human peripheral mononuclear cells (PBMNs). Rare earth mine lot in Xunwu county, the biggest ion absorptive rare earth mine lot of China, was selected as the study site. Another village of Xunwu county, with comparable geological structure and social environment was selected as the control site. Thirty healthy adults were randomly selected from the study site as exposure group and another 30 healthy adults randomly selected from the control site as control group. The blood content of 15 rare earth elements, including La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, were determined by inductive coupled plasma-source mass spectrometry (ICP-MS). The total contents of rare earth elements in the blood were calculated. The TRAP and FCM assays were carried out to analyse the telomerase and apoptosis of human PBMNCs respectively. In the exposure group, the concentration of La, Ce, Dy and Y were significantly higher (P<0.001), and Pr, Nd, Sm, Gd and Yb were higher than those in the control group (P<0.05). The total content of rare earth in the blood of exposure group showed significant difference compared with control group (P<0.001). Telomerase activity in PBMNs of the exposure group was higher than that in the control group (P<0.05); there were 11 adults in the exposure group (30 adults) and 5 adults in control group (30 adults) showed positive telomerase activity. The average age of the exposure group was (38.69 +/- 8.02) years-old, while the control group was (40.45 +/- 9.02) years-old (P >0.05). It was found that there was a significant relationship between telomerase activity and the total content of rare earth elements (P <0.01). 3. The proportion of apoptosis was not different between the two groups (P >0.05), but the cells in the S-phase and G2-M phase were increased (P <0.01) in the exposed group. The telomerase activity of PBMNs in the rare earth elements exposed group was higher than that of the control group, and there is no effect on apoptotic rate of PBMNs, but may promote the diploid DNA replication, and increase the percentage of G2/M and S phase cells.

NO2 possible effects on human health in French Guiana

NASA Astrophysics Data System (ADS)

Gobinddass, Marie-Line; Dendele, Beatrice; Molinie, Jack; panechou-pulcherie, Kathy; Gatineau, Alexandre

2016-04-01

The International Agency for Research on Cancer (IARC) recently declared air pollution carcinogenic to humans. Humans are continuously exposed to nitrogen dioxide (NO2) emissions, a strong oxidizing pollutant commonly found in urban air and homes with unvented combustion appliances. Children and Individuals with asthma have been reported to be more sensitive to NO2exposure. Long-term exposure to NO2 pollution has been reported to induce defective pulmonary function, inflammation, irritations, respiratory infections like bronchitis, lung fibrosis, asthma exacerbation and an increase in inhalational allergies. Pollution peaks are responsible for older people premature death in city. According to W H O guideline values for NO2 emissions, a 1-hour level of 200 μg/m3 (0.1 ppm) and daily annual average of 40 μg/m3 (0.02 ppm) can be a real danger to human health. In general, current exposures in Europe are below this range. However, climate warming changes NO2 emissions and can become a real public health problem in few years. We will study here the temporal series of NO2 variation from data measurement campaigns of 2010 and 2014 in Cayenne city, the French Guiana capital. In this urban zone, NO2 is mainly created by cars traffic. Only 40% comes from combustion in thermal electric plan. A statistical approach will be used to compare NO2 Cayenne level to the daily and the annual threshold. Finally the NO2 evolution related to the climate warming and the growth of road traffic in French Guiana for the next year will be discussed.

Longitudinal Analysis of Particulate Air Pollutants and Adolescent Delinquent Behavior in Southern California.

PubMed

Younan, Diana; Tuvblad, Catherine; Franklin, Meredith; Lurmann, Fred; Li, Lianfa; Wu, Jun; Berhane, Kiros; Baker, Laura A; Chen, Jiu-Chiuan

2017-12-13

Animal experiments and cross-sectional human studies have linked particulate matter (PM) with increased behavioral problems. We conducted a longitudinal study to examine whether the trajectories of delinquent behavior are affected by PM 2.5 (PM with aerodynamic diameter ≤ 2.5 μm) exposures before and during adolescence. We used the parent-reported Child Behavior Checklist at age 9-18 with repeated measures every ~2-3 years (up to 4 behavioral assessments) on 682 children from the Risk Factors for Antisocial Behavior Study conducted in a multi-ethnic cohort of twins born in 1990-1995. Based on prospectively-collected residential addresses and a spatiotemporal model of ambient air concentrations in Southern California, monthly PM 2.5 estimates were aggregated to represent long-term (1-, 2-, 3-year average) exposures preceding baseline and cumulative average exposure until the last assessment. Multilevel mixed-effects models were used to examine the association between PM 2.5 exposure and individual trajectories of delinquent behavior, adjusting for within-family/within-individual correlations and potential confounders. We also examined whether psychosocial factors modified this association. The results sμggest that PM 2.5 exposure at baseline and cumulative exposure during follow-up was significantly associated (p < 0.05) with increased delinquent behavior. The estimated effect sizes (per interquartile increase of PM 2.5 by 3.12-5.18 μg/m 3 ) were equivalent to the difference in delinquency scores between adolescents who are 3.5-4 years apart in age. The adverse effect was stronger in families with unfavorable parent-to-child relationships, increased parental stress or maternal depressive symptoms. Overall, these findings sμggest long-term PM 2.5 exposure may increase delinquent behavior of urban-dwelling adolescents, with the resulting neurotoxic effect aggravated by psychosocial adversities.

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

Knudsen, Gabriel A., E-mail: gabriel.knudsen@nih.gov; Hughes, Michael F.; McIntosh, Katelyn L.

Tetrabromobisphenol A (TBBPA) is currently the world's highest production volume brominated flame retardant. Humans are frequently exposed to TBBPA by the dermal route. In the present study, a parallelogram approach was used to make predictions of internal dose in exposed humans. Human and rat skin samples received 100 nmol of TBBPA/cm{sup 2} skin and absorption and penetrance were determined using a flow-through in vitro system. TBBPA-derived [{sup 14}C]-radioactivity was determined at 6 h intervals in the media and at 24 h post-dosing in the skin. The human skin and media contained an average of 3.4% and 0.2% of the totalmore » dose at the terminal time point, respectively, while the rat skin and media contained 9.3% and 3.5%, respectively. In the intact rat, 14% of a dermally-administered dose of ~ 100 nmol/cm{sup 2} remained in the skin at the dosing site, with an additional 8% reaching systemic circulation by 24 h post-dosing. Relative absorption and penetrance were less (10% total) at 24 h following dermal administration of a ten-fold higher dose (~ 1000 nmol/cm{sup 2}) to rats. However, by 72 h, 70% of this dose was either absorbed into the dosing-site skin or had reached systemic circulation. It is clear from these results that TBBPA can be absorbed by the skin and dermal contact with TBBPA may represent a small but important route of exposure. Together, these in vitro data in human and rat skin and in vivo data from rats may be used to predict TBBPA absorption in humans following dermal exposure. Based on this parallelogram calculation, up to 6% of dermally applied TBBPA may be bioavailable to humans exposed to TBBPA. - Highlights: • Tetrabromobisphenol A is the brominated flame retardant with highest global production volumes. • Humans are frequently exposed to TBBPA by the dermal route, especially via contaminated dust. • Human and rat skin data were integrated using a parallelogram method to predict human absorption. • TBBPA was dermally absorbed and skin contact may represent a small but important route of exposure. • Up to 6% of dermally applied TBBPA may be bioavailable to humans exposed to TBBPA.« less

Developing a Screening Model to Establish Human Risk from Glacial Meltwater Release of Legacy Organochlorine Pollutants at the Silvretta Glacier in the Swiss Alps

NASA Astrophysics Data System (ADS)

Miner, K. R.

2017-12-01

Organochlorine pollutants (OCPs) banned globally by the Stockholm Convention in 2004 are reemerging from melting glaciers in numerous alpine ecosystems. Despite the known OCP influx from glaciers, a study of human risk from uptake of pesticides in glacial meltwater has never been attempted. Our study qualifies human uptake routes and quantifies risk utilizing published meltwater data from the Silvretta Glacier in the Swiss Alps in combination with methodology established by the US Environmental Protection Agency (EPA). Relatively high concentrations of OCPs in Silvretta glacier meltwater reflect proximity to use near high density populations and provide the best estimate of a 95th percentile human risk scenario. This screening level model assesses direct PCB risk to humans through consumption of fish tissue and meltwater. Our model shows a risk for both cancer and non-cancer disease impacts to children with lifetime exposure to glacial meltwater and an average local fish consumption. For adults with an abbreviated 30 year exposure timeframe, the risk for non-cancer effects is negligible and cancer effects are only barely above screening level. Populations that consume higher quantities of local fish are at greater risk, with additional challenges borne by children. Further direct study into the individual level risk to Swiss residents from glacial meltwater pollution is deemed necessary by our screening study.

Intrinsic near-24-h pacemaker period determines limits of circadian entrainment to a weak synchronizer in humans

NASA Technical Reports Server (NTRS)

Wright, K. P. Jr; Hughes, R. J.; Kronauer, R. E.; Dijk, D. J.; Czeisler, C. A.

2001-01-01

Endogenous circadian clocks are robust regulators of physiology and behavior. Synchronization or entrainment of biological clocks to environmental time is adaptive and important for physiological homeostasis and for the proper timing of species-specific behaviors. We studied subjects in the laboratory for up to 55 days each to determine the ability to entrain the human clock to a weak circadian synchronizing stimulus [scheduled activity-rest cycle in very dim (approximately 1.5 lux in the angle of gaze) light-dark cycle] at three approximately 24-h periods: 23.5, 24.0, and 24.6 h. These studies allowed us to test two competing hypotheses as to whether the period of the human circadian pacemaker is near to or much longer than 24 h. We report here that imposition of a sleep-wake schedule with exposure to the equivalent of candle light during wakefulness and darkness during sleep is usually sufficient to maintain circadian entrainment to the 24-h day but not to a 23.5- or 24.6-h day. Our results demonstrate functionally that, in normally entrained sighted adults, the average intrinsic circadian period of the human biological clock is very close to 24 h. Either exposure to very dim light and/or the scheduled sleep-wake cycle itself can entrain this near-24-h intrinsic period of the human circadian pacemaker to the 24-h day.

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

PubMed

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

2013-07-01

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

Assessment of personal exposure to inhalable indoor and outdoor particulate matter for student residents of an academic campus (IIT-Kanpur).

PubMed

Devi, J Jai; Gupta, Tarun; Tripathi, S N; Ujinwal, Kamal K

2009-12-01

Human exposure to particulate matter can have significant harmful effects on the respiratory and cardiovascular system. These effects vary with number, size, and chemical composition of particulate matter, which vary significantly with space and time. The Indian Institute of Technology-Kanpur (IITK), Kanpur, India, is a relatively clean academic campus in the northwest of a heavily polluted city, Kanpur. The major objectives of the study were to evaluate total exposure of fine and coarse fractions of PM(10) to a typical IITK student resident in different indoor microenvironments within the campus; to evaluate personal exposure to student residents during outdoor trips; and to evaluate personal exposure to a typical student resident carrying out routine activities. In order to account for all the sources of particulate matter exposure, measurements on several different days during the pre-monsoon season were carried out in the most common indoor microenvironments in the campus and during outdoor trips outside the campus. A 15-channel optical particle counter (model 1.108, GRIMM) was used to measure continuous real-time particle size distribution from 0.3 to 20 microm diameter. Using this instrument, exposure for 1 h at different indoor microenvironments was determined. Both the effects of location and activity, which, in turn, account for specific indoor sources and number of occupants, respectively, were carefully evaluated. Re-suspension of particles due to movement of people was found to be a major source of coarse particulate matter exposure. On the other hand, combustion sources led to elevated fine particulate levels. Chalk dust was found to be the major source of fine particulate matter in classrooms. Similar results on other sources of particulate matter are discussed in the paper. To assess the personal average size resolved particulate exposure on a student making a day trip outside the campus, study trips to most common public places in the city in a commonly preferred vehicle were made. Striking correlations between sources/activities and increase in fine and/or coarse particle concentration were clearly visible. To investigate the daily personal exposure and its relation to the activities of a typical student residing in the campus, a 24-h exposure study was done on a student who maintained a time-activity diary. The results provide insight into possible sources and their interaction with human activities in modifying the human exposure levels. A comparison between different microenvironments has been attempted for the first time in an Indian scenario using a real-time aerosol measuring instrument.

Human health risk assessment of mercury vapor around artisanal small-scale gold mining area, Palu city, Central Sulawesi, Indonesia.

PubMed

Nakazawa, Koyomi; Nagafuchi, Osamu; Kawakami, Tomonori; Inoue, Takanobu; Yokota, Kuriko; Serikawa, Yuka; Cyio, Basir; Elvince, Rosana

2016-02-01

Emissions of elemental mercury, Hg(0), from artisanal small-scale gold mining activities accounted for 37% of total global Hg(0) emissions in 2010. People who live near gold-mining areas may be exposed to high concentrations of Hg(0). Here, we assessed the human health risk due to Hg(0) exposure among residents of Palu city (Central Sulawesi Province, Indonesia). The area around the city has more than 60t of gold reserves, and the nearby Poboya area is the most active gold-mining site in Indonesia. Owing to its geography, the city experiences alternating land and sea breezes. Sampling was done over a period of 3 years (from 2010 Aug. to 2012 Dec.) intermittently with a passive sampler for Hg(0), a portable handheld mercury analyzer, and a mercury analyzer in four areas of the city and in the Poboya gold-processing area, as well as wind speeds and directions in one area of the city. The 24-h average concentration, wind speed, and wind direction data show that the ambient air in both the gold-processing area and the city was always covered by high concentration of mercury vapor. The Hg(0) concentration in the city was higher at night than in the daytime, owing to the effect of land breezes. These results indicate that the inhabitants of the city were always exposed to high concentrations of Hg(0). The average daytime point-sample Hg(0) concentrations in the city, as measured with a handheld mercury analyzer over 3 days in July 2011, ranged from 2096 to 3299ngm(-3). In comparison, the average daytime Hg(0) concentration in the Poboya gold-processing area was 12,782ngm(-3). All of these concentrations are substantially higher than the World Health Organization air-quality guideline for annual average Hg exposure (1000ngm(-3)). We used the point-sample concentrations to calculate hazard quotient ratios by means of a probabilistic risk assessment method. The results indicated that 93% of the sample population overall was at risk (hazard quotient ratio ≥1 and cut off at the 95th percentile value of the sample population) of mercury toxicity, that is, damage to the central nervous system due to chronic exposure. The corresponding percentages for the northern, central, southern, and western areas of the city were 83%, 84%, 95%, and 95%, respectively. Our results indicate that the residents of Palu city are at serious risk from exposure to high concentrations of atmospheric Hg(0). Copyright © 2015 Elsevier Inc. All rights reserved.

Environmental fate and dietary exposures of humans to TCDD as a result of the spraying of Agent Orange in upland forests of Vietnam.

PubMed

Armitage, James M; Ginevan, Michael E; Hewitt, Andrew; Ross, John H; Watkins, Deborah K; Solomon, Keith R

2015-02-15

The fate and transport of 2,3,7,8-tetrachloro-p-dibenzodioxin (TCDD) released into the environment of South Vietnam (SVN) as a consequence of the aerial application of the herbicidal defoliant Agent Orange (AO) were simulated for a generic upland forest scenario and followed over a 50-year period (1965, 1968 and 1970 onwards). Modeled concentrations of TCDD in the environment were then used as inputs to a human exposure model, which focused on long-term exposures via the food chain. Intake rates and body burdens of TCDD were estimated for adult males over the course of the simulation period and compared to available biomonitoring data. One of the most important factors determining the magnitude of the simulated human exposure to TCDD was the fraction of the chemical deposited directly to soil (where it was assumed to have a degradation half-life of 10 or 15years) relative to the fraction assumed to remain on/in the forest canopy following the spray application (where it was assumed to have a degradation half-life of ≤48h). The simulated body burdens under the various scenarios considered were broadly consistent with the biomonitoring data from SVN collected in the mid-1980s to late 1990s. Taken together, the modeling results and empirical data suggest that highly elevated exposures to TCDD (i.e., body burdens in the several 100s of pg/g lipid range and greater) were not common among people inhabiting upland forest locations in SVN sprayed with AO and that peak and average body burdens were broadly similar to those of the general population of the U.S. in the 1970s and early 1980s. The model-based assessment is consistent with the 'hot spot' hypothesis i.e., potential exposures to TCDD linked to activities conducted on or near former bases where AO was stored are greater than potential exposures in areas subjected to aerial spraying. Copyright © 2014 Elsevier B.V. All rights reserved.

Surveillance of laboratory exposures to human pathogens and toxins: Canada 2016.

PubMed

Bienek, A; Heisz, M; Su, M

2017-11-02

Canada recently enacted legislation to authorize the collection of data on laboratory incidents involving a biological agent. This is done by the Public Health Agency of Canada (PHAC) as part of a comprehensive national program that protects Canadians from the health and safety risks posed by human and terrestrial animal pathogens and toxins. To describe the first year of data on laboratory exposure incidents and/or laboratory-acquired infections in Canada since the Human Pathogens and Toxins Regulations came into effect. Incidents that occurred between January 1 and December 31, 2016 were self-reported by federally-regulated parties across Canada using a standardized form from the Laboratory Incident Notification Canada (LINC) surveillance system. Exposure incidents were described by sector, frequency of occurrence, timeliness of reporting, number of affected persons, human pathogens and toxins involved, causes and corrective actions taken. Microsoft Excel 2010 was used for basic descriptive analyses. In 2016, 46 exposure incidents were reported by holders of 835 active licences in Canada representing 1,352 physical areas approved for work involving a biological agent, for an overall incidence of 3.4%. The number of incidents was highest in the academic (n=16; 34.8%) and hospital (n=12; 26.1%) sectors, while the number of reported incidents was relatively low in the private industry sector. An average of four to five incidents occurred each month; the month of September presented as an outlier with 10 incidents. ​: A total of 100 people were exposed, with no reports of secondary exposure. Four incidents led to suspected (n=3) or confirmed (n=1) cases of laboratory-acquired infection. Most incidents involved pathogens classified at a risk group 2 level that were manipulated in a containment level 2 laboratory (91.3%). Over 22 different species of human pathogens and toxins were implicated, with bacteria the most frequent (34.8%), followed by viruses (26.1%). Eleven (23.9%) incidents involved a security sensitive biologic agent. Procedure breaches (n=15) and sharps-related incidents (n=14) were the most common antecedents to an exposure. In 10 (21.7%) cases, inadvertent possession (i.e., isolation of an unexpected biological agent during routine work) played a role. Possible improvements to standard operating procedures were cited in 71.7% of incidents. Improvements were also indicated for communication (26.1%) and management (23.9%). The Laboratory Incident Notification Canada is one of the first surveillance systems in the world to gather comprehensive data on laboratory incidents involving human pathogens and toxins. Exposure incidents reported in the first year were relatively rare, occurring in less than 4% of containment zones within laboratory settings.

Surveillance of laboratory exposures to human pathogens and toxins: Canada 2016

PubMed Central

Bienek, A; Heisz, M; Su, M

2017-01-01

Background Canada recently enacted legislation to authorize the collection of data on laboratory incidents involving a biological agent. This is done by the Public Health Agency of Canada (PHAC) as part of a comprehensive national program that protects Canadians from the health and safety risks posed by human and terrestrial animal pathogens and toxins. Objective To describe the first year of data on laboratory exposure incidents and/or laboratory-acquired infections in Canada since the Human Pathogens and Toxins Regulations came into effect. Methods Incidents that occurred between January 1 and December 31, 2016 were self-reported by federally-regulated parties across Canada using a standardized form from the Laboratory Incident Notification Canada (LINC) surveillance system. Exposure incidents were described by sector, frequency of occurrence, timeliness of reporting, number of affected persons, human pathogens and toxins involved, causes and corrective actions taken. Microsoft Excel 2010 was used for basic descriptive analyses. Results In 2016, 46 exposure incidents were reported by holders of 835 active licences in Canada representing 1,352 physical areas approved for work involving a biological agent, for an overall incidence of 3.4%. The number of incidents was highest in the academic (n=16; 34.8%) and hospital (n=12; 26.1%) sectors, while the number of reported incidents was relatively low in the private industry sector. An average of four to five incidents occurred each month; the month of September presented as an outlier with 10 incidents. ​ A total of 100 people were exposed, with no reports of secondary exposure. Four incidents led to suspected (n=3) or confirmed (n=1) cases of laboratory-acquired infection. Most incidents involved pathogens classified at a risk group 2 level that were manipulated in a containment level 2 laboratory (91.3%). Over 22 different species of human pathogens and toxins were implicated, with bacteria the most frequent (34.8%), followed by viruses (26.1%). Eleven (23.9%) incidents involved a security sensitive biologic agent. Procedure breaches (n=15) and sharps-related incidents (n=14) were the most common antecedents to an exposure. In 10 (21.7%) cases, inadvertent possession (i.e., isolation of an unexpected biological agent during routine work) played a role. Possible improvements to standard operating procedures were cited in 71.7% of incidents. Improvements were also indicated for communication (26.1%) and management (23.9%). Conclusions The Laboratory Incident Notification Canada is one of the first surveillance systems in the world to gather comprehensive data on laboratory incidents involving human pathogens and toxins. Exposure incidents reported in the first year were relatively rare, occurring in less than 4% of containment zones within laboratory settings. PMID:29770052

DEMONSTRATION OF HUMAN EXPOSURE TOOLS

EPA Science Inventory

The Human Exposure and Atmospheric Sciences Division (HEASD) of the National Exposure Research Laboratory (NERL) conducts research on exposure measurements, human activity patterns, exposure and dose models, and cumulative exposures critical for the Agency to make scientificall...

Health risk of inhalation exposure to sub-10 µm particulate matter and gaseous pollutants in an urban-industrial area in South Africa: an ecological study.

PubMed

Morakinyo, Oyewale Mayowa; Adebowale, Ayo Stephen; Mokgobu, Matlou Ingrid; Mukhola, Murembiwa Stanley

2017-03-13

To assess the health risks associated with exposure to particulate matter (PM 10 ), sulphur dioxide (SO 2 ), nitrogen dioxide (NO 2 ), carbon monoxide (CO) and ozone (O 3 ). The study is an ecological study that used the year 2014 hourly ambient pollution data. The study was conducted in an industrial area located in Pretoria West, South Africa. The area accommodates a coal-fired power station, metallurgical industries such as a coke plant and a manganese smelter. Estimate of possible health risks from exposure to airborne PM 10 , SO 2 , NO 2 , CO and O 3 was performed using the US Environmental Protection Agency human health risk assessment framework. A scenario-assessment approach where normal (average exposure) and worst-case (continuous exposure) scenarios were developed for intermediate (24-hour) and chronic (annual) exposure periods for different exposure groups (infants, children, adults). The normal acute (1-hour) exposure to these pollutants was also determined. Presence or absence of adverse health effects from exposure to airborne pollutants. Average annual ambient concentration of PM 10 , NO 2 and SO 2 recorded was 48.3±43.4, 11.50±11.6 and 18.68±25.4 µg/m 3 , respectively, whereas the South African National Ambient Air Quality recommended 40, 40 and 50 µg/m 3 for PM 10 , NO 2 and SO 2 , respectively. Exposure to an hour's concentration of NO 2 , SO 2 , CO and O 3 , an 8-hour concentration of CO and O 3 , and a 24-hour concentration of PM 10 , NO 2 and SO 2 will not likely produce adverse effects to sensitive exposed groups. However, infants and children, rather than adults, are more likely to be affected. Moreover, for chronic annual exposure, PM 10 , NO 2 and SO 2 posed a health risk to sensitive individuals, with the severity of risk varying across exposed groups. Long-term chronic exposure to airborne PM 10 , NO 2 and SO 2 pollutants may result in health risks among the study population. 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/.

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

PubMed

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

2009-01-01

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

Comparative oesophageal cancer risk assessment of hot beverage consumption (coffee, mate and tea): the margin of exposure of PAH vs very hot temperatures.

PubMed

Okaru, Alex O; Rullmann, Anke; Farah, Adriana; Gonzalez de Mejia, Elvira; Stern, Mariana C; Lachenmeier, Dirk W

2018-03-01

Consumption of very hot (> 65 °C) beverages is probably associated with increased risk of oesophageal cancer. First associations were reported for yerba mate and it was initially believed that high content of polycyclic aromatic hydrocarbons (PAH) might explain the risk. Later research on other beverage groups such as tea and coffee, which are also consumed very hot, found associations with increased risk of oesophageal cancer as well. The risk may therefore not be inherent in any compound contained in mate, but due to temperature. The aim of this study was to quantitatively assess the risk of PAH in comparison with the risk of the temperature effect using the margin of exposure (MOE) methodology. The human dietary benzo[a]pyrene (BaP) and PAH4 (sum of benzo[a]pyrene, benzo[a]anthracene, chrysene, and benzo[b]fluoranthene) exposure through consumption of coffee, mate, and tea was estimated. The oesophageal cancer risk assessment for both PAH and temperature was conducted using the MOE approach. Considering differences in the transfer of the PAH from the leaves of mate and tea or from the ground coffee to the infusion, and considering the different preparation methods, exposures may vary considerably. The average individual exposure in μg/kg bw/day arising from consumption of 1 cup (0.2 L) of infusion was highest for mate (2.85E-04 BaP and 7.22E-04 PAH4). The average per capita exposure in μg/kg bw/day was as follows: coffee (4.21E-04 BaP, 4.15E-03 PAH4), mate (4.26E-03 BaP, 2.45E-02 PAH4), and tea (8.03E-04 BaP, 4.98E-03 PAH4). For all individual and population-based exposure scenarios, the average MOE for BaP and PAH4 was > 100,000 independent of beverage type. MOE values in this magnitude are considered as a very low risk. On the contrary, the MOE for the temperature effect was estimated as < 1 for very hot drinking temperatures, corroborating epidemiological observations about a probable oesophageal cancer risk caused by this behaviour. The temperature effect but not PAH exposure may pose an oesophageal cancer risk. Consumer education on risks associated with consumption of 'very hot' beverages and policy measures to threshold serving temperatures should be discussed.

Predicted outcomes of vaccinating wildlife to reduce human risk of Lyme disease.

PubMed

Tsao, Kimberly; Fish, Durland; Galvani, Alison P

2012-07-01

Vaccination efforts for Lyme disease prevention in humans have focused on wildlife reservoirs to target the causative agent, Borrelia burgdorferi, for elimination in vector ticks. Multiple host species are involved in the transmission and maintenance of the bacterium, but not all host species can be vaccinated effectively. To evaluate vaccinating a subset of hosts in the context of host-tick interactions, we constructed and evaluated a dynamic model of B. burgdorferi transmission in mice. Our analyses indicate that on average, a mouse-targeted vaccine is expected to proportionally reduce infection prevalence among ticks by 56%. However, relative to mouse vaccination, human risk of exposure is dominated by the number of tick bites received per person, the proportion of tick blood meals taken from the highly reservoir-competent white-footed mouse relative to other hosts, and the average number of tick bites per mouse. Variation in these factors reduces the predictability of vaccination outcomes. Additionally, contributions of nonmouse hosts to pathogen maintenance preclude elimination of B. burgdorferi through mouse vaccination alone. Our findings indicate that to increase the impact of wildlife vaccination, reducing tick populations by acaricide application, in addition to targeting additional reservoir-competent host species, should be employed.

Personal exposure to particulate PAHs and anthraquinone and oxidative DNA damages in humans.

PubMed

Wei, Yongjie; Han, In-Kyu; Hu, Min; Shao, Min; Zhang, Junfeng Jim; Tang, Xiaoyan

2010-11-01

Recent studies suggest that DNA oxidative damage be related to the chemical constituents of ambient particles. The purpose of this study was to examine whether particulate polycyclic aromatic hydrocarbons (PAHs) and quinone-structure chemicals increase body burden of oxidative stress in human exposed to heavy traffic volume. We recruited two nonsmoking security guards who worked at a university campus gate near a heavily trafficked road. Each subject wore a personal air sampler for 24h per day to estimate exposures to 24 PAHs and anthraquinone (AnQ) in PM(2.5). Daily pre- and post-work shift spot urines were collected for 29d from each subject. Urine samples were analyzed for 8-hydroxy-2'-deoxyguanosine (8-OHdG). Additionally, using 19 organic tracers other than 24 PAHs and AnQ, a receptor source apportionment model of chemical mass balance was applied to determine the contributions of sources on the PM: gasoline vehicle, diesel vehicle, coal burning, vegetable debris, cooking, natural gas and biomass burning. The relationship among urinary 8-OHdG, individual PAH, and AnQ was demonstrated as follows: the average urinary concentration of 8-OHdG was increased more than three times after 8-h work-shift than those before the work shift. All the 24 PAH and AnQ levels were positively and significantly associated with the post-work urinary 8-OHdG. The results from source apportionment suggest vehicular emission to be the dominant source of personal exposure to PM(2.5). Our finding indicates that personal air exposures to 24 individual PAHs and AnQ originating from traffic emissions are important in increasing oxidative burdens in human body. Copyright © 2010 Elsevier Ltd. All rights reserved.

A Review of Human Health and Ecological Risks due to CO2 Exposure

NASA Astrophysics Data System (ADS)

Hepple, R. P.; Benson, S. M.

2001-05-01

This paper presents an overview of the human health and ecological consequences of exposure to elevated levels of carbon dioxide (CO2) in the context of geologic carbon sequestration. The purpose of this effort is to provide a baseline of information to guide future efforts in risk assessment for CO2 sequestration. Scenarios for hazardous CO2 exposure include surface facility leaks, leaks from abandoned or aging wells, and leakage from geologic CO2 storage structures. Amounts of carbon in various reservoirs, systems, and applications were summarized, and the levels of CO2 encountered in nature and everyday life were compared along with physiologically relevant concentrations. Literature pertaining to CO2 occupational exposure limits, regulations, monitoring, and ecological consequences was reviewed. The OSHA, NIOSH, and ACGIH occupational exposure standards are 0.5% CO2 averaged over a 40 hour week, 3% average for a short-term (15 minute) exposure, and 4% as the maximum instantaneous limit considered immediately dangerous to life and health. All three conditions must be satisfied at all times. Any detrimental effects of low-level CO2 exposure are reversible, including the long-term metabolic compensation required by chronic exposure to 3% CO2. Breathing rate doubles at 3% CO2 and is four times the normal rate at 5% CO2. According to occupational exposure and controlled atmosphere research into CO2 toxicology, CO2 is hazardous via direct toxicity at levels above 5%, concentrations not encountered in nature outside of volcanic settings and water-logged soils. Small leaks do not present any danger to people unless the CO2 does not disperse quickly enough through atmospheric mixing but accumulates instead in depressions and confined spaces. These dangers are the result of CO2 being more dense than air. Carbon dioxide is regulated for diverse purposes but never as a toxic substance. Catastrophic incidents involving large amounts and/or rapid release of CO2 such as Lake Nyos in Cameroon, Mammoth Mountain in California, Dieng Volcanic Complex in Java, Indonesia, and industrial accidents with CO2 fire suppression systems teach that slow leakage rates and effective dilution must be proven to ensure human and environmental safety. Monitoring CO2 levels in occupational settings is done with reliable IR sensors. Remote sensing of low levels of CO2 over long distances cannot be done easily yet, although LIDAR, an airborne laser technique under development, may have good potential. The environmental impacts of elevated CO2 levels on vegetation are being investigated now in free-air CO2 enrichment studies. In general, persistent elevated CO2 levels cause a change in species composition, favoring C3 plants over C4 or CAM. The ecological effects of catastrophic releases are severe but depend upon (a) release rate and amount, (b) surface topography and rate of atmospheric mixing (c) exposure concentrations and duration, (d) the respiratory mechanism of the form of life under discussion, (e) its tolerance for oxygen deprivation, and (f) its ability to maintain homeostatic pH levels. Suppression of root respiration due to elevated soil-gas CO2 concentrations and acidifiction of the root zone are known mechanisms of tree-kill. Soil-gas CO2 in the tree-kill areas at Mammoth Mountain exceeded 20-30% at 15 cm depth. Surface masses of concentrated CO2 probably smother the canopy through oxygen deprivation, but the precise mechanism is not known. Lake Nyos and Mammoth Mountain reveal that catastrophic releases can result in complete dead zones.

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

PubMed Central

Bernier, Meghan R.

2017-01-01

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

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

PubMed

Bernier, Meghan R; Vandenberg, Laura N

2017-01-01

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

Image based Monte Carlo Modeling for Computational Phantom

NASA Astrophysics Data System (ADS)

Cheng, Mengyun; Wang, Wen; Zhao, Kai; Fan, Yanchang; Long, Pengcheng; Wu, Yican

2014-06-01

The evaluation on the effects of ionizing radiation and the risk of radiation exposure on human body has been becoming one of the most important issues for radiation protection and radiotherapy fields, which is helpful to avoid unnecessary radiation and decrease harm to human body. In order to accurately evaluate the dose on human body, it is necessary to construct more realistic computational phantom. However, manual description and verfication of the models for Monte carlo(MC)simulation are very tedious, error-prone and time-consuming. In addiation, it is difficult to locate and fix the geometry error, and difficult to describe material information and assign it to cells. MCAM (CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport Simulation) was developed as an interface program to achieve both CAD- and image-based automatic modeling by FDS Team (Advanced Nuclear Energy Research Team, http://www.fds.org.cn). The advanced version (Version 6) of MCAM can achieve automatic conversion from CT/segmented sectioned images to computational phantoms such as MCNP models. Imaged-based automatic modeling program(MCAM6.0) has been tested by several medical images and sectioned images. And it has been applied in the construction of Rad-HUMAN. Following manual segmentation and 3D reconstruction, a whole-body computational phantom of Chinese adult female called Rad-HUMAN was created by using MCAM6.0 from sectioned images of a Chinese visible human dataset. Rad-HUMAN contains 46 organs/tissues, which faithfully represented the average anatomical characteristics of the Chinese female. The dose conversion coefficients(Dt/Ka) from kerma free-in-air to absorbed dose of Rad-HUMAN were calculated. Rad-HUMAN can be applied to predict and evaluate dose distributions in the Treatment Plan System (TPS), as well as radiation exposure for human body in radiation protection.

A Numerical Simulation of Traffic-Related Air Pollution Exposures in Urban Street Canyons

NASA Astrophysics Data System (ADS)

Liu, J.; Fu, X.; Tao, S.

2016-12-01

Urban street canyons are usually associated with intensive vehicle emissions. However, the high buildings successively along both sides of a street block the dispersion of traffic-generated air pollutants, which enhances human exposure and adversely affects human health. In this study, an urban scale traffic pollution dispersion model is developed with the consideration of street distribution, canyon geometry, background meteorology, traffic assignment, traffic emissions and air pollutant dispersion. Vehicle exhausts generated from traffic flows will first disperse inside a street canyon along the micro-scale wind field (generated by computational fluid dynamics (CFD) model) and then leave the street canyon and further disperse over the urban area. On the basis of this model, the effects of canyon geometry on the distribution of NOx and CO from traffic emissions were studied over the center of Beijing, China. We found that an increase of building height along the streets leads to higher pollution levels inside streets and lower pollution levels outside, resulting in higher domain-averaged concentrations over the area. In addition, street canyons with equal (or highly uneven) building heights on two sides of a street tend to lower the urban-scale air pollution concentrations at pedestrian level. Our results indicate that canyon geometry strongly influences human exposure to traffic pollutants in the populated urban area. Carefully planning street layout and canyon geometry in consideration of traffic demand as well as local weather pattern may significantly reduce the chances of unhealthy air being inhaled by urban residents.

Long-term exposure to high air pollution induces cumulative DNA damages in traffic policemen.

PubMed

Tan, Chaochao; Lu, Shijie; Wang, Yupeng; Zhu, Yan; Shi, Ting; Lin, Mingyue; Deng, Zhonghua; Wang, Zhu; Song, Nana; Li, Shuna; Yang, Pingting; Yang, Liyan; Liu, Yuanyuan; Chen, Zhiheng; Xu, Keqian

2017-09-01

The specific effects of long-term exposure to high air pollution on human health and biological remain unclear. To explore the adverse health effects as well as biological mechanisms and biomarkers for durative exposure to air pollution, 183 traffic policemen and 88 office policemen were enrolled in this study. The concentration of PM2.5 in both the traffic and office policemen's working environments were obtained. Detailed personal questionnaires were completed and levels of inflammation, oxidative stress and DNA damage markers of all participants were analyzed in this study. The average PM2.5 concentration of the intersections of main roads and the offices of control group were 132.4±48.9μg/m 3 and 50.80±38.6μg/m 3 , respectively. The traffic policemen, who stably exposed to at least 2 times higher PM2.5 in their work area as compared with the control group, have a median average duration of 7.00years, and average cumulative intersection duty time reached 8030h. No statistically significant differences in the levels of inflammation markers were observed between the traffic and office policemen. However, the DNA damage markers in traffic policemen shared significant positive correlation with cumulative intersection duty time and higher than those in the office policemen. Multiple linear regression analysis demonstrated that the increase of cumulative intersection duty time by 1h per day for one year was associated with the increase in 8-hydroxy-20-deoxyguanosine of 0.329% (95% CI: 0.249% to 0.409%), tail DNA of 0.051% (95% CI: 0.041% to 0.061%), micronucleus frequency of 0.036‰ (95% CI: 0.03‰ to 0.043‰), and a decrease in glutathione of 0.482% (95% CI: -0.652% to -0.313%). These findings suggest that long-term exposure to high air pollution could induce cumulative DNA damages, supporting the hypothesis that durative exposure to air pollution is associated with an increased risk of cancer. Copyright © 2017 Elsevier B.V. All rights reserved.

Guidance on health effects of toxic chemicals. Safety Analysis Report Update Program

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

Foust, C.B.; Griffin, G.D.; Munro, N.B.

1994-02-01

Martin Marietta Energy Systems, Inc. (MMES), and Martin Marietta Utility Services, Inc. (MMUS), are engaged in phased programs to update the safety documentation for the existing US Department of Energy (DOE)-owned facilities. The safety analysis of potential toxic hazards requires a methodology for evaluating human health effects of predicted toxic exposures. This report provides a consistent set of health effects and documents toxicity estimates corresponding to these health effects for some of the more important chemicals found within MMES and MMUS. The estimates are based on published toxicity information and apply to acute exposures for an ``average`` individual. The healthmore » effects (toxicological endpoints) used in this report are (1) the detection threshold; (2) the no-observed adverse effect level; (3) the onset of irritation/reversible effects; (4) the onset of irreversible effects; and (5) a lethal exposure, defined to be the 50% lethal level. An irreversible effect is defined as a significant effect on a person`s quality of life, e.g., serious injury. Predicted consequences are evaluated on the basis of concentration and exposure time.« less

[Assessment of energy and macronutrients supply in daily food rations of people exposed to hand transmitted vibrations].

PubMed

Zabłocka-Słowińska, Katarzyna; Limburska, Joanna; Prescha, Anna; Pieczyńska, Joanna; Tomczyk, Jarosław; Grajeta, Halina

2011-01-01

Occupational exposure of workers to mechanical hand transmitted vibrations may result in the development of nonspecific lesions. Balanced diet is one of factors that protect human organism against abnormalities resulting from occupational exposure. The aim of this study was to assess the supply of energy and macronutrients in daily food rations (DFR) of people exposed to hand transmitted vibration. Eighty workers, including 37 men (mean age 44.6 years) and 43 women (mean age 44 years) exposed to hand transmitted vibrations were recruited in this study. Of those, 72 people worked in crystal glassworks as glass cutters, 5 people were physiotherapists and 3 were woodcutters. For all workers, there was measured exposure to hand transmitted vibration. Nutritional status was assessed using 24-hour dietary recall; the procedure was repeated 3 times. The results of the nutritional assessment were compared with recommended daily allowances (RDA) for energy, protein, minerals and vitamins, total carbohydrates, total fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), cholesterol and dietary fibre. The average intake of energy in daily food rations of the women was too low while men received the appropriate amount of energy. Average protein intake by men and women was higher than the relevant RDA. The average amount of carbohydrates received by the surveyed women and men were too low, just as the consumption of PUFA, dietary fibre, potassium and calcium. We also found an excessive, average supply of total fat, MUFA, SFA, cholesterol and most of the vitamins with the DFR of the women and men. The nutrition in the group of workers exposed to hand transmitted vibration was found to be imbalanced due to excessive intakes of total fat, saturated fatty acids and cholesterol combined with insufficient consumption of carbohydrates, dietary fibres, potassium and calcium. The co-occurrence of vibration and imbalanced diet may increase the susceptibility of the subjects to cardiovascular and bone diseases.

Effect of Cooking on Speciation and In Vitro Bioaccessibility of Hg and As from Rice, Using Ordinary and Pressure Cookers.

PubMed

Liao, Wen; Wang, Guang; Li, Kaiming; Zhao, Wenbo; Wu, Ye

2018-05-03

Rice is the most widely consumed staple food for a large part of the world's human population, and owing to environmental pollution, it is a major source of human exposure to mercury (Hg) and arsenic (As). We evaluated the impact of cooking on the speciation and bioaccessibility of Hg and As from rice in this study. Results show that the dominant Hg and As species in rice from Guangzhou market in China were their inorganic forms (iHg and iAs), respectively. The cooking process modified the levels of Hg and As. Average Hg and As bioaccessibility in raw rice was 69.74 and 80.32%, respectively. Hg bioaccessibility decreased to 46.22 and 42.37% for pressure- and ordinary-cooked rice, respectively. In contrast, As bioaccessibility remained unchanged except after cooking with a large amount of water. Protein denaturation and the amount of soluble and volatile forms determine the bioaccessibility of Hg and As in cooked rice by being released into the cooking water or into the air. From the bioaccessibility data, the average established daily intake (EDI) values of Hg and As from pressure-cooked rice for children and adults were 0.034 and 0.025 μg kg -1  day -1 (Hg), and 0.735 and 0.559 μg kg -1  day -1 (As), respectively. This study provides novel insights into Hg and As exposure due to rice cooking.

Human Elimination of Phthalate Compounds: Blood, Urine, and Sweat (BUS) Study

PubMed Central

Genuis, Stephen J.; Beesoon, Sanjay; Lobo, Rebecca A.; Birkholz, Detlef

2012-01-01

Background. Individual members of the phthalate family of chemical compounds are components of innumerable everyday consumer products, resulting in a high exposure scenario for some individuals and population groups. Multiple epidemiological studies have demonstrated statistically significant exposure-disease relationships involving phthalates and toxicological studies have shown estrogenic effects in vitro. Data is lacking in the medical literature, however, on effective means to facilitate phthalate excretion. Methods. Blood, urine, and sweat were collected from 20 individuals (10 healthy participants and 10 participants with assorted health problems) and analyzed for parent phthalate compounds as well as phthalate metabolites using high performance liquid chromatography-tandem mass spectrometry. Results. Some parent phthalates as well as their metabolites were excreted into sweat. All patients had MEHP (mono(2-ethylhexyl) phthalate) in their blood, sweat, and urine samples, suggesting widespread phthalate exposure. In several individuals, DEHP (di (2-ethylhexl) phthalate) was found in sweat but not in serum, suggesting the possibility of phthalate retention and bioaccumulation. On average, MEHP concentration in sweat was more than twice as high as urine levels. Conclusions. Induced perspiration may be useful to facilitate elimination of some potentially toxic phthalate compounds including DEHP and MEHP. Sweat analysis may be helpful in establishing the existence of accrued DEHP in the human body. PMID:23213291

Organophosphate Flame Retardants in House Dust from South China and Related Human Exposure Risks.

PubMed

Tan, Hongli; Peng, Changfeng; Guo, Ying; Wang, Xiaodong; Wu, Yan; Chen, Da

2017-09-01

House dust associated with organic pollutants is not only a potential source of pollutants to the outdoor environment, but also a source to human exposure. The present study investigated the occurrence and concentrations of organophosphate flame retardants (OPFRs) in house dust collected from South China dwellings (n = 20). The results revealed a universal presence of most target OPFRs in house dust, with concentrations of ΣOPFRs ranging from 2.06 to 19.95 μg/g. The median concentration of ΣOPFR (9.20 μg/g) was one order of magnitude greater than that of polybrominated diphenyl ethers (0.80 μg/g). The composition of OPFR chemicals in house dust was dominated by chlorinated OPFRs, such as tris(1,3-dichloro-2-propyl) phosphate (TDCPP) and tris(1-chloro-2-propyl) phosphate (TCPP). This compositional pattern was different from what has been reported in indoor dust from many other countries, where tris(2-butoxyethyl) phosphate (TBEP) was generally dominant. The daily intake of OPFRs by adults was estimated to be 1.6 and 4.2 ng/kg body weight/day under average and high exposure scenarios, respectively, and 31.7 and 127 ng/kg body weight/day for toddlers.

Thermal Modeling for the Next Generation of Radiofrequency Exposure Limits: Commentary.

PubMed

Foster, Kenneth R; Ziskin, Marvin C; Balzano, Quirino

2017-07-01

This commentary evaluates two sets of guidelines for human exposure to radiofrequency (RF) energy, focusing on the frequency range above the "transition" frequency at 3-10 GHz where the guidelines change their basic restrictions from specific absorption rate to incident power density, through the end of the RF band at 300 GHz. The analysis is based on a simple thermal model based on Pennes' bioheat equation (BHTE) (Pennes 1948) assuming purely surface heating; an Appendix provides more details about the model and its range of applicability. This analysis suggests that present limits are highly conservative relative to their stated goals of limiting temperature increase in tissue. As applied to transmitting devices used against the body, they are much more conservative than product safety standards for touch temperature for personal electronics equipment that are used in contact with the body. Provisions in the current guidelines for "averaging time" and "averaging area" are not consistent with scaling characteristics of the bioheat equation and should be refined. The authors suggest the need for additional limits on fluence for protection against brief, high intensity pulses at millimeter wave frequencies. This commentary considers only thermal hazards, which form the basis of the current guidelines, and excludes considerations of reported "non-thermal" effects of exposure that would have to be evaluated in the process of updating the guidelines.

Metal(loid) bioaccessibility and inhalation risk assessment: A comparison between an urban and an industrial area.

PubMed

Hernández-Pellón, A; Nischkauer, W; Limbeck, A; Fernández-Olmo, I

2018-04-25

The content of metal(loid)s in particulate matter (PM) is of special concern due to their contribution to overall (PM) toxicity. In this study, the bioaccessibility and human health risk of potentially toxic metal(loid)s associated with PM 10 were investigated in two areas of the Cantabrian region (northern Spain) with different levels of exposure: an industrial area mainly influenced by a ferromanganese alloy plant; and an urban area consisting mainly of residential and commercial activities, but also affected, albeit to a lesser extent by the ferroalloy plant. Total content and bioaccessible fractions in simulated lung fluids (SLFs) of Fe, Mn, Zn, Ni, Cu, Sb, Mo, Cd and Pb were determined by ICP-MS. Gamble's solution and artificial lysosomal fluid (ALF) were used to mimic different conditions inside the human respiratory system. A health risk assessment was performed based on the United States Environmental Protection Agency's (USEPA) methodology. Most metal(loid)s showed moderate and high bioaccessibility in Gamble's solution and ALF, respectively. Despite the high variability between the samples, metal(loid) bioaccessibility was found to be higher on average at the industrial site, suggesting a greater hazard to human health in the proximity of the main metal(loid) sources. Based on the results of the risk assessment, the non-carcinogenic risk associated with Mn exposure was above the safe limit (HQ> 1) under all the studied scenarios at the industrial site and under some specific scenarios at the urban location. The estimated carcinogenic inhalation risk for Cd exposure at the industrial site was found to be within the range between 1.0 × 10 -6 to 1.0 × 10 -4 (uncertainty range) under some scenarios. The results obtained in this study indicate that Mn and Cd inhalation exposure occurring in the vicinities of the studied areas may pose a human health risk. Copyright © 2018 Elsevier Inc. All rights reserved.

Detection of serum AFB1-lysine adduct in Malaysia and its association with liver and kidney functions.

PubMed

Mohd Redzwan, S; Rosita, Jamaluddin; Mohd Sokhini, A M; Nurul 'Aqilah, A R; Wang, Jia-Sheng; Kang, Min-Su; Zuraini, Ahmad

2014-01-01

Aflatoxin is ubiquitously found in many foodstuffs and produced by Aspergillus species of fungi. Of many aflatoxin metabolites, AFB1 is classified by the International Agency for Research on Cancer (IARC) as group one carcinogen and linked to the development of hepatocellular carcinoma (HCC). The study on molecular biomarker of aflatoxin provides a better assessment on the extent of human exposure to aflatoxin. In Malaysia, the occurrences of aflatoxin-contaminated foods have been documented, but there is a lack of data on human exposure to aflatoxin. Hence, this study investigated the occurrence of AFB1-lysine adduct in serum samples and its association with liver and kidney functions. 5ml fasting blood samples were collected from seventy-one subjects (n=71) for the measurement of AFB1-lysine adduct, albumin, total bilirubin, AST (aspartate aminotransferase), ALT (alanine transaminase), ALP (alkaline phosphatase), GGT (gamma-glutamyl transpeptidase), creatinine and BUN (blood urea nitrogen). The AFB1-lysine adduct was detected in all serum samples (100% detection rate) with a mean of 6.85±3.20pg/mg albumin (range: 1.13-18.85pg/mg albumin). Male subjects (mean: 8.03±3.41pg/mg albumin) had significantly higher adduct levels than female subjects (mean: 5.64±2.46pg/mg albumin) (p<0.01). It was noteworthy that subjects with adduct levels greater than average (>6.85pg/mg albumin) had significantly elevated level of total bilirubin (p<0.01), GGT (p<0.05) and creatinine (p<0.01). Nevertheless, only the level of total bilirubin, (r=0.347, p-value=0.003) and creatinine (r=0.318, p-value=0.007) showed significant and positive correlation with the level of AFB1-lysine adduct. This study provides a valuable insight on human exposure to aflatoxin in Malaysia. Given that aflatoxin can pose serious problem to the health, intervention strategies should be implemented to limit/reduce human exposure to aflatoxin. Besides, a study with a big sample size should be warranted in order to assess aflatoxin exposure in the general population of Malaysia. Copyright © 2013 Elsevier GmbH. All rights reserved.

Exposure assessment in front of a multi-band base station antenna.

PubMed

Kos, Bor; Valič, Blaž; Kotnik, Tadej; Gajšek, Peter

2011-04-01

This study investigates occupational exposure to electromagnetic fields in front of a multi-band base station antenna for mobile communications at 900, 1800, and 2100 MHz. Finite-difference time-domain method was used to first validate the antenna model against measurement results published in the literature and then investigate the specific absorption rate (SAR) in two heterogeneous, anatomically correct human models (Virtual Family male and female) at distances from 10 to 1000 mm. Special attention was given to simultaneous exposure to fields of three different frequencies, their interaction and the additivity of SAR resulting from each frequency. The results show that the highest frequency--2100 MHz--results in the highest spatial-peak SAR averaged over 10 g of tissue, while the whole-body SAR is similar at all three frequencies. At distances > 200 mm from the antenna, the whole-body SAR is a more limiting factor for compliance to exposure guidelines, while at shorter distances the spatial-peak SAR may be more limiting. For the evaluation of combined exposure, a simple summation of spatial-peak SAR maxima at each frequency gives a good estimation for combined exposure, which was also found to depend on the distribution of transmitting power between the different frequency bands. Copyright © 2010 Wiley-Liss, Inc.

Mobile phone base station-emitted radiation does not induce phosphorylation of Hsp27.

PubMed

Hirose, H; Sakuma, N; Kaji, N; Nakayama, K; Inoue, K; Sekijima, M; Nojima, T; Miyakoshi, J

2007-02-01

An in vitro study focusing on the effects of low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields act to induce phosphorylation and overexpression of heat shock protein hsp27. First, we evaluated the responses of human cells to microwave exposure at a specific absorption rate (SAR) of 80 mW/kg, which corresponds to the limit of the average whole-body SAR for general public exposure defined as a basic restriction in the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Second, we investigated whether continuous wave (CW) and Wideband Code Division Multiple Access (W-CDMA) modulated signal RF fields at 2.1425 GHz induced activation or gene expression of hsp27 and other heat shock proteins (hsps). Human glioblastoma A172 cells were exposed to W-CDMA radiation at SARs of 80 and 800 mW/kg for 2-48 h, and CW radiation at 80 mW/kg for 24 h. Human IMR-90 fibroblasts from fetal lungs were exposed to W-CDMA at 80 and 800 mW/kg for 2 or 28 h, and CW at 80 mW/kg for 28 h. Under the RF field exposure conditions described above, no significant differences in the expression levels of phosphorylated hsp27 at serine 82 (hsp27[pS82]) were observed between the test groups exposed to W-CDMA or CW signal and the sham-exposed negative controls, as evaluated immediately after the exposure periods by bead-based multiplex assays. Moreover, no noticeable differences in the gene expression of hsps were observed between the test groups and the negative controls by DNA Chip analysis. Our results confirm that exposure to low-level RF field up to 800 mW/kg does not induce phosphorylation of hsp27 or expression of hsp gene family.

Copper Oxide Nanoparticles Impact Several Toxicological Endpoints and Cause Neurodegeneration in Caenorhabditis elegans

PubMed Central

Zanon, Tyler; Kappell, Anthony D.; Petrella, Lisa N.; Andersen, Erik C.; Hristova, Krassimira R.

2016-01-01

Engineered nanoparticles are becoming increasingly incorporated into technology and consumer products. In 2014, over 300 tons of copper oxide nanoparticles were manufactured in the United States. The increased production of nanoparticles raises concerns regarding the potential introduction into the environment or human exposure. Copper oxide nanoparticles commonly release copper ions into solutions, which contribute to their toxicity. We quantified the inhibitory effects of both copper oxide nanoparticles and copper sulfate on C. elegans toxicological endpoints to elucidate their biological effects. Several toxicological endpoints were analyzed in C. elegans, including nematode reproduction, feeding behavior, and average body length. We examined three wild C. elegans isolates together with the Bristol N2 laboratory strain to explore the influence of different genotypic backgrounds on the physiological response to copper challenge. All strains exhibited greater sensitivity to copper oxide nanoparticles compared to copper sulfate, as indicated by reduction of average body length and feeding behavior. Reproduction was significantly reduced only at the highest copper dose, though still more pronounced with copper oxide nanoparticles compared to copper sulfate treatment. Furthermore, we investigated the effects of copper oxide nanoparticles and copper sulfate on neurons, cells with known vulnerability to heavy metal toxicity. Degeneration of dopaminergic neurons was observed in up to 10% of the population after copper oxide nanoparticle exposure. Additionally, mutants in the divalent-metal transporters, smf-1 or smf-2, showed increased tolerance to copper exposure, implicating both transporters in copper-induced neurodegeneration. These results highlight the complex nature of CuO nanoparticle toxicity, in which a nanoparticle-specific effect was observed in some traits (average body length, feeding behavior) and a copper ion specific effect was observed for other traits (neurodegeneration, response to stress). PMID:27911941

Outdoor air pollution in close proximity to a continuous point source

NASA Astrophysics Data System (ADS)

Klepeis, Neil E.; Gabel, Etienne B.; Ott, Wayne R.; Switzer, Paul

Data are lacking on human exposure to air pollutants occurring in ground-level outdoor environments within a few meters of point sources. To better understand outdoor exposure to tobacco smoke from cigarettes or cigars, and exposure to other types of outdoor point sources, we performed more than 100 controlled outdoor monitoring experiments on a backyard residential patio in which we released pure carbon monoxide (CO) as a tracer gas for continuous time periods lasting 0.5-2 h. The CO was emitted from a single outlet at a fixed per-experiment rate of 120-400 cc min -1 (˜140-450 mg min -1). We measured CO concentrations every 15 s at up to 36 points around the source along orthogonal axes. The CO sensors were positioned at standing or sitting breathing heights of 2-5 ft (up to 1.5 ft above and below the source) and at horizontal distances of 0.25-2 m. We simultaneously measured real-time air speed, wind direction, relative humidity, and temperature at single points on the patio. The ground-level air speeds on the patio were similar to those we measured during a survey of 26 outdoor patio locations in 5 nearby towns. The CO data exhibited a well-defined proximity effect similar to the indoor proximity effect reported in the literature. Average concentrations were approximately inversely proportional to distance. Average CO levels were approximately proportional to source strength, supporting generalization of our results to different source strengths. For example, we predict a cigarette smoker would cause average fine particle levels of approximately 70-110 μg m -3 at horizontal distances of 0.25-0.5 m. We also found that average CO concentrations rose significantly as average air speed decreased. We fit a multiplicative regression model to the empirical data that predicts outdoor concentrations as a function of source emission rate, source-receptor distance, air speed and wind direction. The model described the data reasonably well, accounting for ˜50% of the log-CO variability in 5-min CO concentrations.

Respiratory symptoms associated with low level sulphur dioxide exposure in silicon carbide production workers.

PubMed Central

Osterman, J W; Greaves, I A; Smith, T J; Hammond, S K; Robins, J M; Thériault, G

1989-01-01

Relations between pulmonary symptoms and exposure to respirable dust and sulphur dioxide (SO2) were evaluated for 145 silicon carbide (SiC) production workers with an average of 13.9 (range 3-41) years of experience in this industry. Eight hour time weighted average exposures to SO2 were 1.5 ppm or less with momentary peaks up to 4 ppm. Cumulative SO2 exposure averaged 1.94 (range 0.02-19.5) ppm-years. Low level respirable dust exposures also occurred (0.63 +/- 0.26 mg/m3). After adjusting for age and current smoking status in multiple logistic regression models, highly significant, positive, dose dependent relations were found between cumulative and average exposure to SO2, and symptoms of usual and chronic phlegm, usual and chronic wheeze, and mild exertional dyspnoea. Mild and moderate dyspnoea were also associated with most recent exposure to SO2. Cough was not associated with SO2. No pulmonary symptoms were associated with exposure to respirable dust nor were any symptoms attributable to an interaction between dust and SO2. Cigarette smoking was strongly associated with cough, phlegm, and wheezing, but not dyspnoea. A greater than additive (synergistic) effect between smoking and exposure to SO2 was present for most symptoms. These findings suggest that long term, variable exposure to SO2 at 1.5 ppm or less was associated with significantly raised rates of phlegm, wheezing, and mild dyspnoea in SiC production workers, and that current threshold limits for SO2 may not adequately protect workers in this industry. PMID:2789966

HUMAN EXPOSURE ACTIVITY PATTERNS

EPA Science Inventory

Human activity/uptake rate data are necessary to estimate potential human exposure and intake dose to environmental pollutants and to refine human exposure models. Personal exposure monitoring studies have demonstrated the critical role that activities play in explaining and pre...

Rabies in Thailand.

PubMed Central

Mitmoonpitak, C.; Tepsumethanon, V.; Wilde, H.

1998-01-01

The prevalence of canine and human rabies in Thailand has decreased significantly during the last decade. This has been associated with an increasing number of human post-exposure treatments. Educational efforts, mass vaccination of dogs and cats and the use of safe and effective vaccines have all made an impact. The proportion of fluorescent antibody positive dogs, among those examined for rabies averaged 54% indicating that rabies is still a major public health threat. Canine rabies vaccination is not usually performed in animals < 3 months old. However, this study revealed that 14% of rabid dogs were < 3 months old and 42% were < or = 6 months old. This is the age group most likely to interact with humans and other dogs. Our study also supports the World Health Organization's recommendation that observing suspected rabid dogs for 10 days is an adequate and safe practice. PMID:9593486

Validation and Comparison of Two Sampling Methods to Assess Dermal Exposure to Drilling Fluids and Crude Oil

PubMed Central

Galea, Karen S.; McGonagle, Carolyn; Sleeuwenhoek, Anne; Todd, David; Jiménez, Araceli Sánchez

2014-01-01

Dermal exposure to drilling fluids and crude oil is an exposure route of concern. However, there have been no published studies describing sampling methods or reporting dermal exposure measurements. We describe a study that aimed to evaluate a wipe sampling method to assess dermal exposure to an oil-based drilling fluid and crude oil, as well as to investigate the feasibility of using an interception cotton glove sampler for exposure on the hands/wrists. A direct comparison of the wipe and interception methods was also completed using pigs’ trotters as a surrogate for human skin and a direct surface contact exposure scenario. Overall, acceptable recovery and sampling efficiencies were reported for both methods, and both methods had satisfactory storage stability at 1 and 7 days, although there appeared to be some loss over 14 days. The methods’ comparison study revealed significantly higher removal of both fluids from the metal surface with the glove samples compared with the wipe samples (on average 2.5 times higher). Both evaluated sampling methods were found to be suitable for assessing dermal exposure to oil-based drilling fluids and crude oil; however, the comparison study clearly illustrates that glove samplers may overestimate the amount of fluid transferred to the skin. Further comparison of the two dermal sampling methods using additional exposure situations such as immersion or deposition, as well as a field evaluation, is warranted to confirm their appropriateness and suitability in the working environment. PMID:24598941

Assessing pesticide exposure of the aquatic environment in tropical catchments

NASA Astrophysics Data System (ADS)

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

2015-04-01

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

Light Exposure and Eye Growth in Childhood.

PubMed

Read, Scott A; Collins, Michael J; Vincent, Stephen J

2015-10-01

The purpose of this study was to examine the relationship between objectively measured ambient light exposure and longitudinal changes in axial eye growth in childhood. A total of 101 children (41 myopes and 60 nonmyopes), 10 to 15 years of age participated in this prospective longitudinal observational study. Axial eye growth was determined from measurements of ocular optical biometry collected at four study visits over an 18-month period. Each child's mean daily light exposure was derived from two periods (each 14 days long) of objective light exposure measurements from a wrist-worn light sensor. Over the 18-month study period, a modest but statistically significant association between greater average daily light exposure and slower axial eye growth was observed (P = 0.047). Other significant predictors of axial eye growth in this population included children's refractive error group (P < 0.001), sex (P < 0.01), and age (P < 0.001). Categorized according to their objectively measured average daily light exposure and adjusting for potential confounders (age, sex, baseline axial length, parental myopia, nearwork, and physical activity), children experiencing low average daily light exposure (mean daily light exposure: 459 ± 117 lux, annual eye growth: 0.13 mm/y) exhibited significantly greater eye growth than children experiencing moderate (842 ± 109 lux, 0.060 mm/y), and high (1455 ± 317 lux, 0.065 mm/y) average daily light exposure levels (P = 0.01). In this population of children, greater daily light exposure was associated with less axial eye growth over an 18-month period. These findings support the role of light exposure in the documented association between time spent outdoors and childhood myopia.

Occupational trichloroethylene exposure and renal carcinoma risk: evidence of genetic susceptibility by reductive metabolism gene variants

PubMed Central

Moore, Lee E.; Boffetta, Paolo; Karami, Sara; Brennan, Paul; Stewart, Patricia S; Hung, Rayjean; Zaridze, David; Matveev, Vsevolod; Janout, Vladimir; Kollarova, Helena; Bencko, Vladimir; Navratilova, Marie; Szeszenia-Dabrowska, Neonila; Mates, Dana; Gromiec, Jan; Holcatova, Ivana; Merino, Maria; Chanock, Stephen; Chow, Wong-Ho; Rothman, Nathaniel

2010-01-01

Trichloroethylene (TCE) is a suspected renal carcinogen. TCE-associated renal genotoxicity occurs predominantly through glutathione S-transferase (GST) conjugation and bioactivation by renal cysteine beta-lyase (CCBL1). We conducted a case-control study in Central Europe (1,097 cases/1,476 controls), specifically designed to assess risk associated with occupational exposure to TCE through analysis of detailed job histories. All jobs were coded for organic/chlorinated solvent and TCE exposure (ever/never) as well as the frequency and intensity of exposure based on detailed occupational questionnaires, specialized questionnaires, and expert assessments. Increased risk was observed among subjects ever TCE-exposed (OR=1.63, 95% CI: 1.04–2.54). Exposure-response trends were observed among subjects above and below the median exposure [average intensity (OR=1.38, 95% CI:0.81–2.35; OR=2.34, 95% CI:1.05–5.21, p-trend=0.02)]. A significant association was found among TCE-exposed subjects with at least one intact GSTT1 allele (active genotype) (OR=1.88, 95% CI:1.06–3.33) but not among subjects with two deleted alleles (null genotype) (OR=0.93, 95% CI:0.35–2.44, p-interaction=0.18). Similar associations for all exposure metrics including average intensity were observed among GSTT1 active subjects (OR=1.56, 95% CI:0.79–3.10; OR=2.77, 95% CI:1.01–7.58, p-trend=0.02) but not among GSTT1 nulls (OR=0.81, 95% CI:0.24–2.72; OR=1.16, 95% CI:0.27–5.04, p-trend=1.00, p-interaction=0.34). Further evidence of heterogeneity was seen among TCE-exposed subjects with ≥1 minor allele of several CCBL1 tagging SNPs: [rs2293968, rs2280841, rs2259043, rs941960]. These findings provide the strongest evidence to date that TCE exposure is associated with increased renal cancer risk, particularly among individuals carrying polymorphisms in genes that are important in the reductive metabolism of this chemical, and provides biological plausibility of the association in humans. PMID:20663906

Inhalation exposure and risk of polycyclic aromatic hydrocarbons (PAHs) among the rural population adopting wood gasifier stoves compared to different fuel-stove users

NASA Astrophysics Data System (ADS)

Lin, Nan; Chen, Yuanchen; Du, Wei; Shen, Guofeng; Zhu, Xi; Huang, Tianbo; Wang, Xilong; Cheng, Hefa; Liu, Junfeng; Xue, Chunyu; Liu, Guangqing; Zeng, Eddy Y.; Xing, Baoshan; Tao, Shu

2016-12-01

Polycyclic aromatica hydrocarbons (PAHs) are a group of compounds with carcinogenic potentials and residential solid fuel combustion is one major source of PAHs in most developing countries. Replacement of traditional stoves with improved ones is believed to be a practical approach to reduce pollutant emissions, however, field assessments on the performance and consequent impacts on air quality and human health after adopting improved stoves are rare. The study is the first time to quantify inhalation exposure to PAHs among the residents who adopted wood gasifier stoves. The results were compared to those still burning coals in the region and compared to exposure levels for different fuel/stove users in literature. The results showed that the PAHs exposure levels for the wood gasifier stove users were significantly lower than the values for those using traditional wood stoves reported in literature, and the daily exposure concentrations of BaPeq (Benzo[a]pyrene equivalent concentration) can be reduced by 48%-91% if traditional wood stoves were replaced by wood gasifier stoves. The corresponding Incremental Lifetime Cancer Risk (ILCR) decreased approximately four times from 1.94 × 10-4 to 5.17 × 10-5. The average concentration of the total 26 PAHs for the wood users was 1091 ± 722 ng/m3, which was comparable to 1060 ± 927 ng/m3 for those using anthracite coals, but the composition profiles were considerably different. The average BaPeq were 116 and 25.8 ng/m3 for the wood and coal users, respectively, and the corresponding ILCR of the anthracite coal users was 1.69 × 10-5, which was nearly one third of those using the wood gasifier stoves. The wood users exposed to not only high levels of high molecular weight PAHs, but relatively high fractions of particulate phase PAHs in small particles compared to the coal users, resulting in high exposure risks.

Background radiation: natural and man-made.

PubMed

Thorne, M C

2003-03-01

A brief overview and comparison is given of dose rates arising from natural background radiation and the fallout from atmospheric testing of nuclear weapons. Although there are considerable spatial variations in exposure to natural background radiation, it is useful to give estimates of worldwide average overall exposures from the various components of that background. Cosmic-ray secondaries of low linear energy transfer (LET), mainly muons and photons, deliver about 280 microSv a(-1). Cosmic-ray neutrons deliver about another 100 microSv a(-1). These low- and high-LET exposures are relatively uniform to the whole body. The effective dose rate from cosmogenic radionuclides is dominated by the contribution of 12 microSv a(-1) from 14C. This is due to relatively uniform irradiation of all organs and tissues from low-energy beta particles. Primordial radionuclides and their progeny (principally the 238U and 232Th series, and 40K) contribute about 480 microSv a(-1) of effective dose by external irradiation. This is relatively uniform photon irradiation of the whole body. Internally incorporated 40K contributes a further 165 microSv a(-1) of effective dose in adults, mainly from beta particles, but with a significant gamma component. Equivalent doses from 40K are somewhat higher in muscle than other soft tissues, but the distinction is less than a factor of three. Uranium and thorium series radionuclides give rise to an average effective dose rate of around 120 microSv a(-1). This includes a major alpha particle component, and exposures of radiosensitive tissues in lung, liver, kidney and the skeleton are recognised as important contributors to effective dose. Overall, these various sources give a worldwide average effective dose rate of about 1160 microSv a(-1). Exposure to 222Rn, 220Rn and their short-lived progeny has to be considered separately. This is very variable both within and between countries. For 222Rn and its progeny, a worldwide average effective dose rate is about 1105 microSv a(-1). For 220Rn and its progeny, the corresponding value is 91 microSv a(-1). In both cases, the effective dose is mainly due to a particle irradiation of the bronchial tissues of the lungs. Overall, the worldwide average effective dose rate from natural background is about 2400 microSv a(-1) or 2.4 mSv a(-1). For comparison, worldwide average effective dose rates from weapons fallout peaked at 113 microSv a(-1) (about 5% of natural background) in 1963 and have since fallen to about 5.5 microSv a(-1) (about 0.2% of natural background). These values perhaps serve to emphasise that even gross insults to the natural environment from anthropogenic releases of radioactive materials are likely to be of limited significance when set in the context of the ambient radioactive environment within which all organisms, including humans, have developed.

Anthropogenic climate change and allergen exposure: The role of plant biology.

PubMed

Ziska, Lewis H; Beggs, Paul J

2012-01-01

Accumulation of anthropogenic gases, particularly CO(2), is likely to have 2 fundamental effects on plant biology. The first is an indirect effect through Earth's increasing average surface temperatures, with subsequent effects on other aspects of climate, such as rainfall and extreme weather events. The second is a direct effect caused by CO(2)-induced stimulation of photosynthesis and plant growth. Both effects are likely to alter a number of fundamental aspects of plant biology and human health, including aerobiology and allergic diseases, respectively. This review highlights the current and projected effect of increasing CO(2) and climate change in the context of plants and allergen exposure, emphasizing direct effects on plant physiologic parameters (eg, pollen production) and indirect effects (eg, fungal sporulation) related to diverse biotic and abiotic interactions. Overall, the review assumes that future global mitigation efforts will be limited and suggests a number of key research areas that will assist in adapting to the ongoing challenges to public health associated with increased allergen exposure. Published by Mosby, Inc.

FDTD analysis of body-core temperature elevation in children and adults for whole-body exposure.

PubMed

Hirata, Akimasa; Asano, Takayuki; Fujiwara, Osamu

2008-09-21

The temperature elevations in anatomically based human phantoms of an adult and a 3-year-old child were calculated for radio-frequency whole-body exposure. Thermoregulation in children, however, has not yet been clarified. In the present study, we developed a computational thermal model of a child that is reasonable for simulating body-core temperature elevation. Comparison of measured and simulated temperatures revealed thermoregulation in children to be similar to that of adults. Based on this finding, we calculated the body-core temperature elevation in a 3-year-old child and an adult for plane-wave exposure at the basic restriction in the international guidelines. The body-core temperature elevation in the 3-year-old child phantom was 0.03 degrees C at a whole-body-averaged specific absorption rate of 0.08 W kg(-1), which was 35% smaller than in the adult female. This difference is attributed to the child's higher body surface area-to-mass ratio.

Similarity of Bisphenol A Pharmacokinetics in Rhesus Monkeys and Mice: Relevance for Human Exposure

PubMed Central

Taylor, Julia A.; vom Saal, Frederick S.; Welshons, Wade V.; Drury, Bertram; Rottinghaus, George; Hunt, Patricia A.; Toutain, Pierre-Louis; Laffont, Céline M.; VandeVoort, Catherine A.

2011-01-01

Objective Daily adult human exposure to bisphenol A (BPA) has been estimated at < 1 μg/kg, with virtually complete first-pass conjugation in the liver in primates but not in mice. We measured unconjugated and conjugated BPA levels in serum from adult female rhesus monkeys and adult female mice after oral administration of BPA and compared findings in mice and monkeys with prior published data in women. Methods Eleven adult female rhesus macaques were fed 400 μg/kg deuterated BPA (dBPA) daily for 7 days. Levels of serum dBPA were analyzed by isotope-dilution liquid chromatography–mass spectrometry (0.2 ng/mL limit of quantitation) over 24 hr on day 1 and on day 7. The same dose of BPA was fed to adult female CD-1 mice; other female mice were administered 3H-BPA at doses ranging from 2 to 100,000 μg/kg. Results In monkeys, the maximum unconjugated serum dBPA concentration of 4 ng/mL was reached 1 hr after feeding and declined to low levels by 24 hr, with no significant bioaccumulation after seven daily doses. Mice and monkeys cleared unconjugated serum BPA at virtually identical rates. We observed a linear (proportional) relationship between administered dose and serum BPA in mice. Conclusions BPA pharmacokinetics in women, female monkeys, and mice is very similar. By comparison with approximately 2 ng/mL unconjugated serum BPA reported in multiple human studies, the average 24-hr unconjugated serum BPA concentration of 0.5 ng/mL in both monkeys and mice after a 400 μg/kg oral dose suggests that total daily human exposure is via multiple routes and is much higher than previously assumed. PMID:20855240

Standard setting processes and regulations for environmental contaminants in drinking water: State versus federal needs and viewpoints

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

Sidhu, K.S.

1991-06-01

The primary objective of a standard setting process is to arrive at a drinking water concentration at which exposure to a contaminant would result in no known or potential adverse health effect on human health. The drinking water standards also serve as guidelines to prevent pollution of water sources and may be applicable in some cases as regulatory remediation levels. The risk assessment methods along with various decision making parameters are used to establish drinking water standards. For carcinogens classified in Groups A and B by the United States Environmental Protection Agency (USEPA) the standards are set by using nonthresholdmore » cancer risk models. The linearized multistage model is commonly used for computation of potency factors for carcinogenic contaminants. The acceptable excess risk level may vary from 10(-6) to 10(-4). For noncarcinogens, a threshold model approach based on application of an uncertainty factor is used to arrive at a reference dose (RfD). The RfD approach may also be used for carcinogens classified in Group C by the USEPA. The RfD approach with an additional uncertainty factory of 10 for carcinogenicity has been applied in the formulation of risk assessment for Group C carcinogens. The assumptions commonly used in arriving at drinking water standards are human life expectancy, 70 years; average human body weight, 70 kg; human daily drinking water consumption, 2 liters; and contribution of exposure to the contaminant from drinking water (expressed as a part of the total environmental exposure), 20%. Currently, there are over 80 USEPA existing or proposed primary standards for organic and inorganic contaminants in drinking water. Some of the state versus federal needs and viewpoints are discussed.« less

Analysis of 4-hydroxy-1-(-3-pyridyl)-1-butanone (HPB)-releasing DNA adducts in human exfoliated oral mucosa cells by liquid chromatography-electrospray ionization-tandem mass spectrometry

PubMed Central

Stepanov, Irina; Muzic, John; Le, Chap T.; Sebero, Erin; Villalta, Peter; Ma, Bin; Jensen, Joni; Hatsukami, Dorothy; Hecht, Stephen S.

2013-01-01

Quantitation of DNA adducts could provide critical information on the relationship between exposure to tobacco smoke and cancer risk in smokers. In this study, we developed a robust and sensitive liquid chromatography-tandem mass spectrometry method for the analysis of 4-hydroxy-1-(3-pyridyl)-1-butanone (HPB1)-releasing DNA adducts in human oral cells, a non-invasive source of DNA for biomarker studies. Isolated DNA undergoes acid hydrolysis, after which samples are purified by solid-phase extraction and analyzed by LC-ESI-MS/MS. The developed method was applied for analysis of samples obtained via collection with a commercial mouthwash from 30 smokers and 15 nonsmokers. In smokers, the levels of HPB-releasing DNA adducts averaged 12.0 pmol HPB/mg DNA (detected in 20 out of 28 samples with quantifiable DNA yield) and in nonsmokers, the levels of adducts averaged 0.23 pmol/mg DNA (detected in 3 out of 15 samples). For the 30 smoking subjects, matching buccal brushings were also analyzed and HPB-releasing DNA adducts were detected in 24 out of 27 samples with quantifiable DNA yield, averaging 44.7 pmol HPB/mg DNA. The levels of adducts in buccal brushings correlated with those in mouthwash samples of smokers (R = 0.73, p < 0.0001). Potentially the method can be applied in studies of individual susceptibility to tobacco-induced cancers in humans. PMID:23252610

[Human mercury exposure and irregular menstrual cycles in relation to artisanal gold mining in Colombia].

PubMed

Rodríguez-Villamizar, Laura Andrea; Jaimes, Diana Carolina; Manquián-Tejos, Adelaida; Sánchez, Luz Helena

2015-08-01

Artisanal mining commonly extracts gold with an amalgamation process that uses mercury. The reproductive effects from exposure to elemental mercury used in gold mining have not been sufficiently studied. To evaluate the effect of the exposure to elemental mercury used in gold mining on menstrual cycle regularity and the occurrence of miscarriages in Colombia. An analytical cross-sectional study was conducted. The participants were female residents of gold mining districts, with a history of exposure to elemental mercury. Menstrual regularity and the occurrence of miscarriages were compared between these women and an unexposed group. Exposure and outcome variables were registered based on a questionnaire which was evaluated for its test-retest reproducibility. Prevalence rates were calculated using a binomial model and goodness-of-fit was evaluated. A total of 72 women exposed to mercury and 121 unexposed women participated. The average time of exposure to mercury among exposed women was 19.58 ± 9.53 years. The adjusted prevalence of irregular menstruation over the last six months was higher in the group of women chronically exposed to mercury vapors (PR=1.59, 95% CI 0.93-2.73), while there was no difference in the proportion of women with a history of miscarriages. Exposure to elemental mercury used in artisanal gold mining may be associated with a higher prevalence of irregular menstrual cycles but not with the occurrence of miscarriage.

A systematic review of Bisphenol A "low dose" studies in the context of human exposure: a case for establishing standards for reporting "low-dose" effects of chemicals.

PubMed

Teeguarden, Justin G; Hanson-Drury, Sesha

2013-12-01

Human exposure to the chemical Bisphenol A is almost ubiquitous in surveyed industrialized societies. Structural features similar to estrogen confer the ability of Bisphenol A (BPA) to bind estrogen receptors, giving BPA membership in the group of environmental pollutants called endocrine disruptors. References by scientists, the media, political entities, and non-governmental organizations to many toxicity studies as "low dose" has led to the belief that exposure levels in these studies are similar to humans, implying that BPA is toxic to humans at current exposures. Through systematic, objective comparison of our current, and a previous compilation of the "low-dose" literature to multiple estimates of human external and internal exposure levels, we found that the "low-dose" moniker describes exposures covering 8-12 orders of magnitude, the majority (91-99% of exposures) being greater than the upper bound of human exposure in the general infant, child and adult U.S. Population. "low dose" is therefore a descriptor without specific meaning regarding human exposure. Where human exposure data are available, for BPA and other environmental chemicals, reference to toxicity study exposures by direct comparison to human exposure would be more informative, more objective, and less susceptible to misunderstanding. Copyright © 2013 Elsevier Ltd. All rights reserved.

Consumption of freshwater fish by recreational and native freshwater anglers in the upper St-Maurice (Quebec, Canada) and estimation of the intake of methylmercury in humans

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

Loranger, S.; Houde, L.; Schetagne, R.

1995-12-31

Hydro-Quebec is planning to build two hydroelectric reservoirs in the upper Saint-Maurice River, which would flood about 80% of the surrounding area. The methylmercury (MeHg) content in freshwater fish will therefore tend to increase during the first few years. This development will have a direct impact on the amount of MeHg that the actual users of this river section are exposed to. The objective of this study is to assess the consumption of local fish of these target groups using a Monte-Carlo approach. This study is part of a larger research project aimed at assessing human exposure and the healthmore » risks related to MeHg contamination in local fish. The fish consumption rate for recreational freshwater anglers was calculated using the duration of the average annual fishing trip, the average number of catches per species, the average fish weight per species exceeding a specific length of fish usually caught, and the edible portion of fish consumed. This rate was calculated for the native communities based on the total number of meals per year per species, the average fish weight per species, and the edible portion. Based on these calculations, average intake for sport fishermen is estimated at 6.9 g/day (sd = 6.4). This value is 5 to 25 times lower on average than for other North American native communities. However, it must be pointed out that the food habits of the native population were very similar to those of non-native populations; less than 30% of the food comes from traditional sources.« less

Incidence of polybrominated diphenyl ethers in central air conditioner filter dust from a new office building.

PubMed

Ni, Hong-Gang; Cao, Shan-Ping; Chang, Wen-Jing; Zeng, Hui

2011-07-01

This study examined polybrominated diphenyl ethers (PBDEs) in central air conditioner filter (CACF) dust from a new office building in Shenzhen, China. Human exposure to PBDE via dust inhalation and ingestion were also estimated. PBDEs level in CACF dust was lower than those in the other countries and regions. Approximately 0.671 pg/kg bw/day PM(2.5) (Particulate Matter up to 2.5 μm in size) bounded Σ(15)PBDEs can be inhaled deep into the lungs and 4.123 pg/kg bw/day PM(10) (Particulate Matter up to 10 μm in size) bounded Σ(15)PBDEs tend to be deposited in the upper parts of the respiratory system. The average total intake of Σ(15)PBDEs via dust inhalation and ingestion for adults reached ∼ 141 pg/kg bw/day in this building. This value was far below the reference dose (RfD) recommended by United States Environmental Protection Agency. Human exposure to PBDEs via dust inhalation and ingestion in the new building is less than the old ones. Copyright © 2010 Elsevier Ltd. All rights reserved.

Time series analysis and mortality model of dog bite victims presented for treatment at a referral clinic for rabies exposure in Monrovia, Liberia, 2010-2013.

PubMed

Olarinmoye, Ayodeji O; Ojo, Johnson F; Fasunla, Ayotunde J; Ishola, Olayinka O; Dakinah, Fahnboah G; Mulbah, Charles K; Al-Hezaimi, Khalid; Olugasa, Babasola O

2017-08-01

We developed time trend model, determined treatment outcome and estimated annual human deaths among dog bite victims (DBVs) from 2010 to 2013 in Monrovia, Liberia. Data obtained from clinic records included victim's age, gender and site of bite marks, site name of residence of rabies-exposed patients, promptness of care sought, initial treatment and post-exposure-prophylaxis (PEP) compliance. We computed DBV time-trend plot, seasonal index and year 2014 case forecast. Associated annual human death (AHD) was estimated using a standardized decision tree model. Of the 775 DBVs enlisted, care seeking time was within 24h of injury in 328 (42.32%) DBVs. Victim's residential location, site of bite mark, and time dependent variables were significantly associated with treatment outcome (p< 0.05). The equation X^ t =28.278-0.365t models the trend of DBVs. The high (n=705, 90.97%) defaulted PEP and average 155 AHD from rabies implied urgent need for policy formulation on national programme for rabies prevention in Liberia. Copyright © 2017 Elsevier Ltd. All rights reserved.

Coherent activity between brain regions that code for value is linked to the malleability of human behavior

PubMed Central

Cooper, Nicole; Bassett, Danielle S.; Falk, Emily B.

2017-01-01

Brain activity in medial prefrontal cortex (MPFC) during exposure to persuasive messages can predict health behavior change. This brain-behavior relationship has been linked to areas of MPFC previously associated with self-related processing; however, the mechanism underlying this relationship is unclear. We explore two components of self-related processing – self-reflection and subjective valuation – and examine coherent activity between relevant networks of brain regions during exposure to health messages encouraging exercise and discouraging sedentary behaviors. We find that objectively logged reductions in sedentary behavior in the following month are linked to functional connectivity within brain regions associated with positive valuation, but not within regions associated with self-reflection on personality traits. Furthermore, functional connectivity between valuation regions contributes additional information compared to average brain activation within single brain regions. These data support an account in which MPFC integrates the value of messages to the self during persuasive health messaging and speak to broader questions of how humans make decisions about how to behave. PMID:28240271

Phthalates and alternative plasticizers and potential for contact exposure from children's backpacks and toys.

PubMed

Xie, Mingjie; Wu, Yaoxing; Little, John C; Marr, Linsey C

2016-01-01

This work focuses on the mass content of plasticizers in children's backpacks and toys, and their mass transfer from product surfaces to cotton wipes. The mass content of plasticizers in six backpacks and seven toys was measured by extracting them in tetrahydrofuran. Bis(2-ethylhexyl) terephthalate (DEHT) was the most common plasticizer, dominating the composition of plasticizers in four backpacks (average mass content in product polyvinyl chloride, 5.38 ± 1.98%-25.5 ± 3.54%) and six plastic toys (8.17 ± 1.85%-21.2 ± 1.11%). The surface of each product was wiped with three dry and three wet (by isopropanol) cotton wipes, so as to evaluate the mass transfer of plasticizers to clothing and human skin, respectively. DEHT was the most common plasticizer detected on wipe samples. There were strong correlations (backpacks r=0.90; plastic toys r=0.96) between average mass transfer of DEHT to wet wipes and its average mass content in the product. The mass transfers of the five dominant plasticizers in one backpack to both dry and wet wipes were also correlated (both r=1.00) with their mass contents. These results suggest that the mass transfer of plasticizers from products to clothing or human skin is strongly associated with their mass content.

Toxic metals in tissues of fishes from the Black Sea and associated human health risk exposure.

PubMed

Plavan, Gabriel; Jitar, Oana; Teodosiu, Carmen; Nicoara, Mircea; Micu, Dragos; Strungaru, Stefan-Adrian

2017-03-01

The anthropogenic activities in the Black Sea area are responsible for toxic metal contamination of sea food products. In this study, several toxic metals: cadmium, lead, nickel, chromium, and copper were quantified in different tissues (digestive tract, muscle, skeleton, skin) of nine fish species (Neogobius melanostomus, Belone belone, Solea solea, Trachurus mediterraneus ponticus, Sardina pilchardus, Engraulis encrasicolus, Pomatomus saltatrix, Sprattus sprattus, Scorpaena porcus) by using atomic absorption spectrometer with a high-resolution continuum source and graphite furnace technique (HR-CS GF-AAS), and the risk of fish meat consumption by the young human population was evaluated. These metals are used in high amounts in industries located near the coastline such as shipyard construction and industrial plants. Toxic metal accumulation depends on fish feeding behavior, abiotic conditions, metal chemistry, and animal physiology. For instance, cadmium was measured in the muscle of the investigated species and average values of 0.0008-0.0338 mg kg -1 were obtained. The lowest average value of this metal was measured at benthic species N. melanostomus and the highest at the pelagic predator T. mediterraneus ponticus. Generally, the highest metal concentration was measured in the digestive tract that has the role of biofilter for these contaminants. The risk of contamination is significantly reduced by avoiding the consumption of certain fish tissues (digestive tract and skin for copper and skeleton for nickel). An estimation of the dietary metal intake to young consumers was realized for each of the studied species of fish from Romanian, Bulgarian, and Turkish waters, during the period 2001-2014 in order to evaluate the risks of chronic exposure in time due to metal toxicity. This estimation is important for the prevention of chronic exposure due to metal toxicity. Food exposure to studied metals showed a negative trend for Romania, Turkey, and Bulgaria based on the data provided by this study. The young consumers were highly exposed to these elements during the 2001-2006 period as proven by the results from this study.

Investigation of natural effective gamma dose rates case study: Ardebil Province in Iran

PubMed Central

2012-01-01

Gamma rays pose enough energy to induce chemical changes that may be biologically important for the normal functioning of body cells. The external exposure of human beings to natural environmental gamma radiation normally exceeds that from all man-made sources combined. In this research natural background gamma dose rates and corresponding annual effective doses were determined for selected cities of Ardebil province. Outdoor gamma dose rates were measured using an Ion Chamber Survey Meter in 105 locations in selected districts. Average absorbed doses for Ardebil, Sar-Ein, Germy, Neer, Shourabil Recreational Lake, and Kosar were determined as 265, 219, 344, 233, 352, and 358 nSv/h, respectively. Although dose rates recorded for Germi and Kosar are comparable with some areas with high natural radiation background, however, the dose rates in other districts are well below the levels reported for such locations. Average annual effective dose due to indoor and outdoor gamma radiation for Ardebil province was estimated as 1.73 (1.35–2.39) mSv, which is on average 2 times higher than the world population weighted average. PMID:23369115

Phosphorylation and gene expression of p53 are not affected in human cells exposed to 2.1425 GHz band CW or W-CDMA modulated radiation allocated to mobile radio base stations.

PubMed

Hirose, H; Sakuma, N; Kaji, N; Suhara, T; Sekijima, M; Nojima, T; Miyakoshi, J

2006-09-01

A large-scale in vitro study focusing on low-level radiofrequency (RF) fields from mobile radio base stations employing the International Mobile Telecommunication 2000 (IMT-2000) cellular system was conducted to test the hypothesis that modulated RF fields induce apoptosis or other cellular stress response that activate p53 or the p53-signaling pathway. First, we evaluated the response of human cells to microwave exposure at a specific absorption rate (SAR) of 80 mW/kg, which corresponds to the limit of the average whole-body SAR for general public exposure defined as a basic restriction by the International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Second, we investigated whether continuous wave (CW) and wideband code division multiple access (W-CDMA) modulated signal RF fields at 2.1425 GHz induced apoptosis or any signs of stress. Human glioblastoma A172 cells were exposed to W-CDMA radiation at SARs of 80, 250, and 800 mW/kg, and CW radiation at 80 mW/kg for 24 or 48 h. Human IMR-90 fibroblasts from fetal lungs were exposed to both W-CDMA and CW radiation at a SAR of 80 mW/kg for 28 h. Under the RF field exposure conditions described above, no significant differences in the percentage of apoptotic cells were observed between the test groups exposed to RF signals and the sham-exposed negative controls, as evaluated by the Annexin V affinity assay. No significant differences in expression levels of phosphorylated p53 at serine 15 or total p53 were observed between the test groups and the negative controls by the bead-based multiplex assay. Moreover, microarray hybridization and real-time RT-PCR analysis showed no noticeable differences in gene expression of the subsequent downstream targets of p53 signaling involved in apoptosis between the test groups and the negative controls. Our results confirm that exposure to low-level RF signals up to 800 mW/kg does not induce p53-dependent apoptosis, DNA damage, or other stress response in human cells.

Effect of 900 MHz electromagnetic fields on nonthermal induction of heat-shock proteins in human leukocytes.

PubMed

Lim, Hooi B; Cook, Greg G; Barker, Anthony T; Coulton, Les A

2005-01-01

Despite many studies, the evidence as to whether radiofrequency fields are detrimental to health remains controversial, and the debate continues. Cells respond to some abnormal physiological conditions by producing cytoprotective heat-shock (or stress) proteins. The aim of this study was to determine whether exposure to mobile phone-type radiation causes a nonthermal stress response in human leukocytes. Human peripheral blood was sham-exposed or exposed to 900 MHz fields (continuous-wave or GSM-modulated signal) at three average specific absorption rates (0.4, 2.0 and 3.6 W/kg) for different durations (20 min, 1 h and 4 h) in a calibrated TEM cell placed in an incubator to give well-controlled atmospheric conditions at 37 degrees C and 95% air/5% CO(2). Positive (heat-stressed at 42 degrees C) and negative (kept at 37 degrees C) control groups were incubated simultaneously in the same incubator. Heat caused an increase in the number of cells expressing stress proteins (HSP70, HSP27), measured using flow cytometry, and this increase was dependent on time. However, no statistically significant difference was detected in the number of cells expressing stress proteins after RF-field exposure. These results suggest that mobile phone-type radiation is not a stressor of normal human lymphocytes and monocytes, in contrast to mild heating.

The food contaminant and nephrotoxin ochratoxin A enhances Wnt1 inducible signaling protein 1 and tumor necrosis factor-α expression in human primary proximal tubule cells.

PubMed

Hennemeier, Isabell; Humpf, Hans-Ulrich; Gekle, Michael; Schwerdt, Gerald

2012-09-01

The underlying molecular mechanisms of nanomolar ochratoxin A (OTA) concentrations, especially those on pathophysiological relevant gene expression in target tissue and underlying signaling mechanisms are unknown. qPCR arrays showed that 14 days exposure of human primary proximal tubule cells to 10 nM OTA influences the expression of genes that are related to inflammation, malignant transformation, and epithelial-to-mesenchymal transition. Wnt1 inducible signaling protein 1 (WISP1), an oncogenic, and profibrotic growth factor, turned out to be the gene with the strongest upregulation. Its expression, and that of TNF-α, an important inflammatory mediator, was further investigated in human renal cells and in primary human lung fibroblasts. OTA-induced upregulation of WISP1 and TNF-α occurs only in renal cells. Inhibition of ERK1/2 activation reverses the effect of OTA on WISP1 and TNF-α expression. Wnt or other signaling pathways were not involved. Upregulation of WISP1 and TNF-α occured independently of each other. Long-term exposure of human kidney cells with OTA concentrations expectable in renal tissue due to average dietary intake leads in an ERK1/2-dependent manner to pathogenetic alterations of gene expression, notably WISP1 and TNF-α. Renal long-term risk by OTA is actually not excludable and argues for low but rational safety levels. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measuring urinary N-acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine (IPMA3) as a potential biomarker of isoprene exposure.

PubMed

Alwis, K Udeni; Bailey, T Liz; Patel, Dhrusti; Wang, Liqun; Blount, Benjamin C

2016-10-19

Isoprene, the 2-methyl analog of 1,3-butadiene, is identified as a possible human carcinogen by the International Agency for Research on Cancer (IARC). Isoprene is ubiquitous in the environment with numerous natural and anthropogenic sources. Tobacco smoke is the main exogenous source of isoprene exposure in indoor environments. Among smoke constituents, isoprene is thought to contribute significantly to cancer risk; however, no selective urinary biomarkers of isoprene exposure have been identified for humans. In this manuscript, we measured the minor isoprene metabolite IPMA1 (mixture of N-acetyl-S-(1-[hydroxymethyl]-2-methyl-2-propen-1-yl)-L-cysteine and N-acetyl-S-(2-hydroxy-3-methyl-3-buten-1-yl)-L-cysteine), and we identified IPMA3 (N-acetyl-S-(4-hydroxy-2-methyl-2-buten-1-yl)-L-cysteine) as a major isoprene metabolite and novel isoprene exposure biomarker for humans. Urinary isoprene metabolites were measured using ultra high performance liquid chromatography coupled with electrospray ionization triple quad tandem mass spectrometry (UPLC/ESI-MSMS). The detection rates of IPMA1 and IPMA3 are <20% and 82%, respectively. The selectivity and abundance of IPMA3 make it a useful urinary biomarker of isoprene exposure. The limit of detection of IPMA3 in urine was 0.5 ng mL -1 . IPMA3 was stable under different storage temperatures and following ten freeze-thaw cycles. The average recovery of urine spiked with IPMA3 at three different levels was 99%. IPMA3 was measured in urine samples received from 75 anonymous subjects; the median (25th percentile, 75th percentile) IPMA3 level in smokers was 36.2 (18.2, 56.8) ng mL -1 and non-smokers 2.31 (2.31, 4.38) ng mL -1 . Application of this method to large population studies will help to characterize isoprene exposure and assess potential health impact. Published by Elsevier B.V.

The influence of street layouts and viaduct settings on daily carbon monoxide exposure and intake fraction in idealized urban canyons.

PubMed

Hang, Jian; Luo, Zhiwen; Wang, Xuemei; He, Lejian; Wang, Baomin; Zhu, Wei

2017-01-01

Environmental concerns have been raised on the adverse health effects of vehicle emissions in micro-scale traffic-crowded street canyons, especially for pedestrians and residents living in near-road buildings. Viaduct design is sometimes used to improve transportation efficiency but possibly affects urban airflow and the resultant exposure risk, which have been rarely investigated so far. The personal intake fraction (P_IF) is defined as the average fraction of total emissions that is inhaled by each person of a population (1 ppm = 1 × 10 -6 ), and the daily carbon monoxide (CO) pollutant exposure (E t ) is estimated by multiplying the average concentration of a specific micro-environment within one day. As a novelty, by considering time activity patterns and breathing rates in various micro-environments for three age groups, this paper introduces IF and E t into computational fluid dynamic (CFD) simulation to quantify the impacts of street layouts (street width/building height W/H = 1, 1.5, 2), source location, viaduct settings and noise barriers on the source-exposure correlation when realistic CO sources are defined. Narrower streets experience larger P_IF (1.51-5.21 ppm) and CO exposure, and leeward-side buildings always attain higher vehicular pollutant exposure than windward-side. Cases with a viaduct experience smaller P_IF (3.25-1.46 ppm) than cases without a viaduct (P_IF = 5.21-2.23 ppm) if the single ground-level CO source is elevated onto the viaduct. With two CO sources (both ground-level and viaduct-level), daily CO exposure rises 2.80-3.33 times but P_IF only change slightly. Noise barriers above a viaduct raise concentration between barriers, but slightly reduce vehicular exposure in near-road buildings. Because people spend most of their time indoors, vehicular pollutant exposure within near-road buildings can be 6-9 times that at pedestrian level. Although further studies are still required to provide practical guidelines, this paper provides effective methodologies to quantify the impacts of street/viaduct configurations on human exposure for urban design purpose. Copyright © 2016 Elsevier Ltd. All rights reserved.

Associations of maternal exposure to triclosan, parabens, and other phenols with prenatal maternal and neonatal thyroid hormone levels.

PubMed

Berger, Kimberly; Gunier, Robert B; Chevrier, Jonathan; Calafat, Antonia M; Ye, Xiaoyun; Eskenazi, Brenda; Harley, Kim G

2018-05-24

Environmental phenols and parabens are commonly used in personal care products and other consumer products and human exposure to these chemicals is widespread. Although human and animal studies suggest an association between exposure to phenols and parabens and thyroid hormone levels, few studies have investigated the association of in utero exposure to these chemicals and thyroid hormones in pregnant women and their neonates. We measured four environmental phenols (triclosan, benzophenone-3, and 2,4- and 2,5-dichlorophenol), and three parabens (methyl-, propyl-, and butyl paraben) in urine collected from mothers at two time points during pregnancy as part of the CHAMACOS (Center for the Health Assessment of Mothers and Children of Salinas) study. We measured free thyroxine (T4), total T4, and thyroid-stimulating hormone (TSH) in serum of the pregnant women (N = 454) and TSH in their neonates (N = 365). We examined potential confounding by a large number of additional chemical exposures and used Bayesian Model Averaging (BMA) to select the most influential chemicals to include in regression models. We observed negative associations of prenatal urinary concentrations of propyl paraben and maternal TSH (β for two-fold increase = -3.26%, 95% CI: -5.55, -0.90) and negative associations of 2,4-dichlorophenol and maternal free T4 (β for two-fold increase = -0.05, 95% CI: -0.08, -0.02), after controlling for other chemical exposures. We observed negative associations of triclosan with maternal total T4 after controlling for demographic variables, but this association became non-significant after controlling for other chemicals (β for two-fold increase = -0.05, 95% CI: -0.11, 0.00). We found evidence that environmental phenols and parabens are associated with lower TSH and free T4 in pregnant women after controlling for related chemical exposures. Copyright © 2018 Elsevier Inc. All rights reserved.

Preclinical and first-in-human evaluation of PRX-105, a PEGylated, plant-derived, recombinant human acetylcholinesterase-R

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

Atsmon, Jacob; Sackler Faculty of Medicine, Tel Aviv University; Brill-Almon, Einat

PRX-105 is a plant-derived recombinant version of the human ‘read-through’ acetylcholinesterase splice variant (AChE-R). Its active site structure is similar to that of the synaptic variant, and it displays the same affinity towards organophosphorus (OP) compounds. As such, PRX-105 may serve as a bio-scavenger for OP pesticides and chemical warfare agents. To assess its potential use in prophylaxis and treatment of OP poisoning we conducted several preliminary tests, reported in this paper. Intravenous (IV) PRX-105 was administered to mice either before or after exposure to an OP toxin. All mice who received an IV dose of 50 nmol/kg PRX-105, 2more » min before being exposed to 1.33 × LD{sub 50} and 1.5 × LD{sub 50} of toxin and 10 min after exposure to 1.5 × LD{sub 50} survived. The pharmacokinetic and toxicity profiles of PRX-105 were evaluated in mice and mini-pigs. Following single and multiple IV doses (50 to 200 mg/kg) no deaths occurred and no significant laboratory and histopathological changes were observed. The overall elimination half-life (t{sub ½}) in mice was 994 (± 173) min. Additionally, a first-in-human study, to assess the safety, tolerability and pharmacokinetics of the compound, was conducted in healthy volunteers. The t{sub ½} in humans was substantially longer than in mice (average 26.7 h). Despite the small number of animals and human subjects who were assessed, the fact that PRX-105 exerts a protective and therapeutic effect following exposure to lethal doses of OP, its favorable safety profile and its relatively long half-life, renders it a promising candidate for treatment and prophylaxis against OP poisoning and warrants further investigation. - Highlights: • PRX-105 is a PEGylated plant-derived recombinant human acetylcholinesterase-R. • PRX-105 is a promising bio-scavenger for organophosphorous toxins at lethal doses. • PRX-105 was shown to protect animals both prophylactically and post-poisoning. • First-in-human study exhibited its safety, tolerability and pharmacokinetics. • Toxicokinetic animal studies have shown a favorable safety profile.« less

Ototoxic effects of occupational exposure to styrene and co-exposure to styrene and noise.

PubMed

Sliwińska-Kowalska, Mariola; Zamyslowska-Szmytke, Ewa; Szymczak, Wieslaw; Kotylo, Piotr; Fiszer, Marta; Wesolowski, Wiktor; Pawlaczyk-Luszczynska, Malgorzata

2003-01-01

Ototoxicity of styrene and the synergistic action of styrene and noise have been shown in rats. The respective data in humans are scarce and equivocal. This study evaluated the effects of occupational exposure to styrene and combined exposures to styrene and noise on hearing. The study group, comprised of 290-yacht yard and plastic factory workers, was exposed to a mixture of organic solvents, having styrene as its main compound. The reference group, totaling 223 subjects, included (1) white-collar workers, exposed neither to solvents nor noise and (2) metal factory workers, exposed exclusively to noise. All subjects were assessed by means of a detailed questionnaire and underwent otorhinolaryngological and audiometric examinations. Multiple logistic regression analysis revealed almost a 4-fold (or 3.9; 95% CI = 2.4-6.2) increase in the odds of developing hearing loss related to styrene exposure. The factors adjusted for were: age, gender, current occupational exposure to noise, and exposure to noise in the past. In cases of the combined exposures to styrene and noise, the odds ratios were two to three times higher than the respective values for styrene-only and noise-only exposed subjects. The mean hearing thresholds--adjusted for age, gender, and exposure to noise--were significantly higher in the solvent-exposed group than in the unexposed reference group at all frequencies tested. A positive linear relationship existed between an averaged working life exposure to styrene concentration and a hearing threshold at the frequencies of 6 and 8 kHz. This study provides the epidemiological evidence that occupational exposure to styrene is related to an increased risk of hearing loss. Combined exposures to noise and styrene seem to be more ototoxic than exposure to noise alone.

ANALYSIS OF HUMAN ACTIVITY DATA FOR USE IN MODELING ENVIRONMENTAL EXPOSURES

EPA Science Inventory

Human activity data are a critical part of exposure models being developed by the US EPA's National Exposure Research Laboratory (NERL). An analysis of human activity data within NERL's Consolidated Human Activity Database (CHAD) was performed in two areas relevant to exposure ...

Contrast Medium Exposure During Computed Tomography and Risk of Development of End-Stage Renal Disease in Patients With Chronic Kidney Disease

PubMed Central

Hsieh, Ming-Shun; Chiu, Chien-Shan; How, Chorng-Kuang; Chiang, Jen-Huai; Sheu, Meei-Ling; Chen, Wen-Chi; Lin, Hsuan-Jen; Hsieh, Vivian Chia-Rong; Hu, Sung-Yuan

2016-01-01

Abstract The aim of the study was to investigate the long-term association between contrast medium exposure during computed tomography (CT) and the subsequent development of end-stage renal disease (ESRD) in patients with chronic kidney disease (CKD). We conducted a population-based cohort study using Taiwan's National Health Insurance Research Database. A total of 7100 patients with nonadvanced CKD who underwent contrast medium-enhanced CT were identified and served as the study cohort. To avoid selection bias, we used the propensity score to match 7100 nonadvanced CKD patients, who underwent noncontrast medium-enhanced CT to serve as the comparison cohort. The age, sex, index year, and frequency of undergoing CTs were also matched between the study and comparison cohorts. Participants were followed until a new diagnosis of ESRD or December 31, 2011. Hazard ratios (HRs) with 95% confidence interval (95% CI) were calculated using the Cox proportional hazards regression. Contrast medium exposure was not identified as a risk factor for developing ESRD in nonadvanced CKD patients after confounders adjustment (adjusted HR = 0.91; 95% CI, 0.66–1.26; P = 0.580). We further divided the patients who underwent CTs with contrast medium use into ≤1 exposure per year on average, >1 and <2 exposure per year on average, and ≥2 exposure per year on average. After adjusting for confounders, we identified a much higher risk for developing ESRD in the 2 groups of >1 and <2 exposure per year on average and ≥2 exposure per year on average (adjusted HR = 8.13; 95% CI, 5.57–11.87 and adjusted HR = 12.08; 95% CI, 7.39–19.75, respectively) compared with the patients who underwent CTs without contrast medium use. This long-term follow-up study demonstrated that contrast medium exposure was not associated with an increased risk of ESRD development in nonadvanced CKD patients. PMID:27100424

Radiological safety assessment inside ancient Egyptian tombs in Saqqara.

PubMed

El-Kameesy, S U; Salama, E; El-Fiki, S A; Ehab, M; Rühm, W

2016-12-01

Many archaeological sites in Egypt are unique worldwide, such as ancient tombs and pyramids, because they document fundamental developments in human civilization that took place several thousands of years ago. For this reason, these sites are visited by numerous visitors every year. The present work is devoted to provide a pre-operational radiological baseline needed to quantify occupational radiation exposure at the famous Saqqara region in Cairo, Egypt. A hyperpure Ge detector has been used in the γ-ray spectrometric analysis while the (222)Rn concentration was measured using a portable radon monitor RTM 1688-2, SARAD. The mean specific activities of (226)Ra, (232)Th and (40)K in the samples collected from the interior walls of the Saqqara tombs were determined and found to show average values of 16, 8.5 and 45 Bq kg(-1), respectively. The concentration of radon was measured inside the tombs Serapeum, South tomb and the Zoser Pyramid (fifth level) and an associated average working level of 0.83 WL was obtained. In order to avoid the health hazards associated with the exposure to radon during the long period of work inside these tombs, proposed solutions are introduced.

Dioxin-like polychlorinated biphenyls, polychlorinated dibenzo-p-dioxins, and polychlorinated dibenzofurans in seafood samples from Malaysia: estimated human intake and associated risks.

PubMed

Leong, Yin-Hui; Gan, Chee-Yuen; Majid, Mohamed Isa Abdul

2014-07-01

A total of 127 and 177 seafood samples from Malaysia were analyzed for polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (dl-PCBs), respectively. The World Health Organization-toxic-equivalency quotients (WHO-TEQ) of PCDD/Fs varied from 0.13 to 1.03 pg TEQ g(-1), whereas dl-PCBs ranged from 0.33 to 1.32 pg TEQ g(-1). Based on food-consumption data from the global environment monitoring system-food contamination monitoring and assessment programme, calculated dietary exposures to PCDD/Fs and dl-PCBs from seafood for the general population in Malaysia were 0.042 and 0.098 pg TEQ kg(-1) body weight day(-1), respectively. These estimations were quite different from the values calculated using the Malaysian food-consumption statistics (average of 0.313 and 0.676 pg TEQ kg(-1) body weight day(-1) for PCDD/Fs and PCBs, respectively). However, both of the dietary exposure estimations were lower than the tolerable daily intake recommended by WHO. Thus, it is suggested that seafood from Malaysia does not pose a notable risk to the health of the average consumer.

Airborne asbestos exposures associated with gasket and packing replacement: a simulation study of flange and valve repair work and an assessment of exposure variables.

PubMed

Madl, Amy K; Devlin, Kathryn D; Perez, Angela L; Hollins, Dana M; Cowan, Dallas M; Scott, Paul K; White, Katherine; Cheng, Thales J; Henshaw, John L

2015-02-01

A simulation study was conducted to evaluate worker and area exposure to airborne asbestos associated with the replacement of asbestos-containing gaskets and packing materials from flanges and valves and assess the influence of several variables previously not investigated. Additionally, potential of take home exposures from clothing worn during the study was characterized. Our data showed that product type, ventilation type, gasket location, flange or bonnet size, number of flanges involved, surface characteristics, gasket surface adherence, and even activity type did not have a significant effect on worker exposures. Average worker asbestos exposures during flange gasket work (PCME=0.166 f/cc, 12-59 min) were similar to average worker asbestos exposures during valve overhaul work (PCME=0.165 f/cc, 7-76 min). Average 8-h TWA asbestos exposures were estimated to range from 0.010 to 0.062 f/cc. Handling clothes worn during gasket and packing replacement activities demonstrated exposures that were 0.71% (0.0009 f/cc 40-h TWA) of the airborne asbestos concentration experienced during the 5 days of the study. Despite the many variables considered in this study, exposures during gasket and packing replacement occur within a relatively narrow range, are below current and historical occupational exposure limits for asbestos, and are consistent with previously published data. Copyright © 2014 Elsevier Inc. All rights reserved.

Human health risk assessment related to contaminated land: state of the art.

PubMed

Swartjes, F A

2015-08-01

Exposure of humans to contaminants from contaminated land may result in many types of health damage ranging from relatively innocent symptoms such as skin eruption or nausea, on up to cancer or even death. Human health protection is generally considered as a major protection target. State-of-the-art possibilities and limitations of human health risk assessment tools are described in this paper. Human health risk assessment includes two different activities, i.e. the exposure assessment and the hazard assessment. The combination of these is called the risk characterization, which results in an appraisal of the contaminated land. Exposure assessment covers a smart combination of calculations, using exposure models, and measurements in contact media and body liquids and tissue (biomonitoring). Regarding the time frame represented by exposure estimates, biomonitoring generally relates to exposure history, measurements in contact media to actual exposures, while exposure calculations enable a focus on exposure in future situations. The hazard assessment, which is different for contaminants with or without a threshold for effects, results in a critical exposure value. Good human health risk assessment practice accounts for tiered approaches and multiple lines of evidence. Specific attention is given here to phenomena such as the time factor in human health risk assessment, suitability for the local situation, background exposure, combined exposure and harmonization of human health risk assessment tools.

Morphometric Characterization of Rat and Human Alveolar Macrophage Cell Models and their Response to Amiodarone using High Content Image Analysis.

PubMed

Hoffman, Ewelina; Patel, Aateka; Ball, Doug; Klapwijk, Jan; Millar, Val; Kumar, Abhinav; Martin, Abigail; Mahendran, Rhamiya; Dailey, Lea Ann; Forbes, Ben; Hutter, Victoria

2017-12-01

Progress to the clinic may be delayed or prevented when vacuolated or "foamy" alveolar macrophages are observed during non-clinical inhalation toxicology assessment. The first step in developing methods to study this response in vitro is to characterize macrophage cell lines and their response to drug exposures. Human (U937) and rat (NR8383) cell lines and primary rat alveolar macrophages obtained by bronchoalveolar lavage were characterized using high content fluorescence imaging analysis quantification of cell viability, morphometry, and phospholipid and neutral lipid accumulation. Cell health, morphology and lipid content were comparable (p < 0.05) for both cell lines and the primary macrophages in terms of vacuole number, size and lipid content. Responses to amiodarone, a known inducer of phospholipidosis, required analysis of shifts in cell population profiles (the proportion of cells with elevated vacuolation or lipid content) rather than average population data which was insensitive to the changes observed. A high content image analysis assay was developed and used to provide detailed morphological characterization of rat and human alveolar-like macrophages and their response to a phospholipidosis-inducing agent. This provides a basis for development of assays to predict or understand macrophage vacuolation following inhaled drug exposure.

Improving human health outcomes with a low-cost intervention to reduce exposures from lead acid battery recycling: Dong Mai, Vietnam.

PubMed

Ericson, Bret; Duong, Thi To; Keith, John; Nguyen, Trong Cuu; Havens, Deborah; Daniell, William; Karr, Catherine J; Ngoc Hai, Doan; Van Tung, Lo; Thi Nhi Ha, Tran; Wilson, Brian; Hanrahan, David; Croteau, Gerry; Patrick Taylor, Mark

2018-02-01

This study details the first comprehensive evaluation of the efficacy of a soil lead mitigation project in Dong Mai village, Vietnam. The village's population had been subject to severe lead poisoning for at least a decade as a result of informal Used Lead Acid Battery (ULAB) recycling. Between July 2013 to February 2015, Pure Earth and the Centre for Environment and Community Development (Hanoi, Vietnam) implemented a multi-faceted environmental and human health intervention. The intervention consisted of a series of institutional and low-cost engineering controls including the capping of lead contaminated surface soils, cleaning of home interiors, an education campaign and the construction of a work-clothes changing and bathing facility. The mitigation project resulted in substantial declines in human and environmental lead levels. Remediated home yard and garden areas decreased from an average surface soil concentration of 3940mg/kg to <100mg/kg. One year after the intervention, blood lead levels in children (<6 years old) were reduced by an average of 67%-from a median of 40.4μg/dL to 13.3μg/dL. The Dong Mai project resulted in significantly decreased environmental and biological lead levels demonstrating that low-cost, rapid and well-coordinated interventions could be readily applied elsewhere to significantly reduce preventable human health harm. Copyright © 2017 Elsevier Inc. All rights reserved.

Calculated SAR distributions in a human voxel phantom due to the reflection of electromagnetic fields from a ground plane between 65 MHz and 2 GHz

NASA Astrophysics Data System (ADS)

Findlay, R. P.; Dimbylow, P. J.

2008-05-01

If an electromagnetic field is incident normally onto a perfectly conducting ground plane, the field is reflected back into the domain. This produces a standing wave above the ground plane. If a person is present within the domain, absorption of the field in the body may cause problems regarding compliance with electromagnetic guidelines. To investigate this, the whole-body averaged specific energy absorption rate (SAR), localised SAR and ankle currents in the voxel model NORMAN have been calculated for a variety of these exposures under grounded conditions. The results were normalised to the spatially averaged field, a technique used to determine a mean value for comparison with guidelines when the field varies along the height of the body. Additionally, the external field values required to produce basic restrictions for whole-body averaged SAR have been calculated. It was found that in all configurations studied, the ICNIRP reference levels and IEEE MPEs provided a conservative estimate of these restrictions.

Characterization of rabies post-exposure prophylaxis in a region of the eastern Amazon, state of Pará, Brazil, between 2000 and 2014.

PubMed

De Paula, N S; Saraiva, E A; Araújo, I M; Nascimento, K K G; Xavier, D A; Santos, K S; Abreu, E M N; Guimãraes, R J P S; Abel, I

2018-06-01

Animal bites are a serious public health issue, and prevention strategies have been consistently documented worldwide. The aim of this study was to characterize human anti-rabies treatment in 11 counties of the Salgado microregion, Pará state, Brazil, which borders the Bragantina microregion, where exposures of human rabies were reported in 2004 and 2005. A descriptive retrospective study was conducted using anti-rabies treatment notifications registered in the Information System for Notifiable Diseases (SINAN) database of the State Department of Public Health of Pará (SESPA) from January 2000 to December 2014. In this period, 13,403 exposures were reported, with a growing annual trend (Y = 68.571x + 344.96). The years 2012 and 2013 presented the highest exposure incidence. Salinópolis was the county with the highest average annual incidence per 10,000 persons (62.83), followed by São João de Pirabas (43.28) and São Caetano de Odivelas (41.27). Most patients were males (59.6%) and were 1-19 years old (48.7%). The main species involved in aggressions were dogs (74.1%), followed by bats (13.1%) and cats (7.4%). Biting was the most common kind of exposure, mostly on the lower limbs (39.6%). This study shows that aggression by bats was the second most common cause of demand for the service in the region for the past 14 years. The low quality of records may increase the difficulty of rabies surveillance in Pará. © 2018 Blackwell Verlag GmbH.

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

EPA Science Inventory

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

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

40 CFR 159.170 - Human epidemiological and exposure studies.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Human epidemiological and exposure... Information § 159.170 Human epidemiological and exposure studies. Information must be submitted which concerns... that a correlation may exist between exposure to a pesticide and observed adverse effects in humans...

Flight crew exposure to ozone concentrations affecting the visual system.

PubMed

Daubs, J

1980-02-01

To estimate the potential for ozone (O3) effects on the human visual system in flight, O3 concentrations in Boeing 747-100 cockpits were measured during routine flights between London and the United States. From a review of previous reports, it appears that O3 may have both beneficial and harmful effects but that further studies of the visual system responses to O3 are needed before the present findings of 0.030 parts per million (ppm) mean O3, 0.200 ppm maximum O3, and 0.261 ppm-hours average cumulative O3 exposure can be effectively evaluated. Unexpectedly high O3 concentrations were encountered at altitudes below 18,000 feet and, at times, the O3 concentration was observed to decrease as flight level was increased. The clinical, operational, and policy implications of these findings are discussed.

FDTD computation of temperature elevation in the elderly for far-field RF exposures.

PubMed

Nomura, Tomoki; Laakso, Ilkka; Hirata, Akimasa

2014-03-01

Core temperature elevation and perspiration in younger and older adults is investigated for plane-wave exposure at whole-body averaged specific absorption rate of 0.4 W kg(-1). Numeric Japanese male model is considered together with a thermoregulatory response formula proposed in the authors' previous study. The frequencies considered were at 65 MHz and 2 GHz where the total power absorption in humans becomes maximal for the allowable power density prescribed in the international guidelines. From the computational results used here, the core temperature elevation in the older adult model was larger than that in the younger one at both frequencies. The reason for this difference is attributable to the difference of sweating, which is originated from the difference in the threshold activating the sweating and the decline in sweating in the legs.

Quantification of ETS exposure in hospitality workers who have never smoked

PubMed Central

2010-01-01

Background Environmental Tobacco Smoke (ETS) was classified as human carcinogen (K1) by the German Research Council in 1998. According to epidemiological studies, the relative risk especially for lung cancer might be twice as high in persons who have never smoked but who are in the highest exposure category, for example hospitality workers. In order to implement these results in the German regulations on occupational illnesses, a valid method is needed to retrospectively assess the cumulative ETS exposure in the hospitality environment. Methods A literature-based review was carried out to locate a method that can be used for the German hospitality sector. Studies assessing ETS exposure using biological markers (for example urinary cotinine, DNA adducts) or questionnaires were excluded. Biological markers are not considered relevant as they assess exposure only over the last hours, weeks or months. Self-reported exposure based on questionnaires also does not seem adequate for medico-legal purposes. Therefore, retrospective exposure assessment should be based on mathematical models to approximate past exposure. Results For this purpose a validated model developed by Repace and Lowrey was considered appropriate. It offers the possibility of retrospectively assessing exposure with existing parameters (such as environmental dimensions, average number of smokers, ventilation characteristics and duration of exposure). The relative risk of lung cancer can then be estimated based on the individual cumulative exposure of the worker. Conclusion In conclusion, having adapted it to the German hospitality sector, an existing mathematical model appears to be capable of approximating the cumulative exposure. However, the level of uncertainty of these approximations has to be taken into account, especially for diseases with a long latency period such as lung cancer. PMID:20704719

Quantification of ETS exposure in hospitality workers who have never smoked.

PubMed

Kolb, Stefanie; Brückner, Ulrike; Nowak, Dennis; Radon, Katja

2010-08-12

Environmental Tobacco Smoke (ETS) was classified as human carcinogen (K1) by the German Research Council in 1998. According to epidemiological studies, the relative risk especially for lung cancer might be twice as high in persons who have never smoked but who are in the highest exposure category, for example hospitality workers. In order to implement these results in the German regulations on occupational illnesses, a valid method is needed to retrospectively assess the cumulative ETS exposure in the hospitality environment. A literature-based review was carried out to locate a method that can be used for the German hospitality sector. Studies assessing ETS exposure using biological markers (for example urinary cotinine, DNA adducts) or questionnaires were excluded. Biological markers are not considered relevant as they assess exposure only over the last hours, weeks or months. Self-reported exposure based on questionnaires also does not seem adequate for medico-legal purposes. Therefore, retrospective exposure assessment should be based on mathematical models to approximate past exposure. For this purpose a validated model developed by Repace and Lowrey was considered appropriate. It offers the possibility of retrospectively assessing exposure with existing parameters (such as environmental dimensions, average number of smokers, ventilation characteristics and duration of exposure). The relative risk of lung cancer can then be estimated based on the individual cumulative exposure of the worker. In conclusion, having adapted it to the German hospitality sector, an existing mathematical model appears to be capable of approximating the cumulative exposure. However, the level of uncertainty of these approximations has to be taken into account, especially for diseases with a long latency period such as lung cancer.

Occurrence and risk assessment of organophosphate esters in drinking water from Eastern China.

PubMed

Ding, Jinjian; Shen, Xiaoli; Liu, Weiping; Covaci, Adrian; Yang, Fangxing

2015-12-15

Organophosphate esters (OPEs) are ubiquitous in the environment and may pose potential health risks to humans. Drinking water is suspected as one possible exposure pathway of OPEs to humans. In this study, we investigated the residues of 9 OPEs in five types of drinking water in Eastern China. The median concentrations of Σ9OPEs were determined to be 3.99, 4.50, 27.6, 59.2 and 192ng/L in the bottled, well, barreled, direct drinking and tap waters, respectively. Triethyl phosphate (TEP) was the most abundant OPE in the tap water and filtered drinking water with median concentrations of 50.2 and 30.2ng/L, respectively. The mixture of tri(chloropropyl) phosphate (TCPP) and tri(chloroisopropyl) phosphate (TCIPP), named here as TCPP, dominated in the barreled and well water with median concentrations of 8.04 and 2.49ng/L, respectively. The calculated average daily doses of OPEs ranged from 0.14 to 7.07ng/kgbw/day for people consuming the five different types of drinking water. Among the drinking water, the tap water exhibited the highest exposure doses of OPEs. The calculated non-cancer hazard quotients (10(-4)-10(-7)) from OPEs were much lower than the theoretical threshold of risk. The carcinogenic risks posed by TCEP were very low (<10(-7)) for all types of drinking water. The results revealed that there was currently low risk to human health from exposure to OPEs through drinking water in Eastern China. Copyright © 2015 Elsevier B.V. All rights reserved.

AN OVERVIEW OF HUMAN EXPOSURE MODELING ACTIVITIES AT THE U.S. EPA'S NATIONAL EXPOSURE RESEARCH LABORATORY

EPA Science Inventory

The computational modeling of human exposure to environmental pollutants is one of the primary activities of the US Environmental Protection Agency (USEPA)'s National Exposure Research Laboratory (NERL). Assessment of human exposures is a critical part of the overall risk assessm...

40 CFR 158.1060 - Post-application exposure-criteria for testing

Code of Federal Regulations, 2012 CFR

2012-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1060 Post-application exposure...) Occupational human post-application exposure to pesticide residues on plants or in soil could occur as the...) Residential human post-application exposure to pesticide residues on plants or in soil could occur. Such uses...

40 CFR 158.1060 - Post-application exposure-criteria for testing

Code of Federal Regulations, 2011 CFR

2011-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1060 Post-application exposure...) Occupational human post-application exposure to pesticide residues on plants or in soil could occur as the...) Residential human post-application exposure to pesticide residues on plants or in soil could occur. Such uses...

40 CFR 158.1060 - Post-application exposure-criteria for testing.

Code of Federal Regulations, 2014 CFR

2014-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1060 Post-application exposure...) Occupational human post-application exposure to pesticide residues on plants or in soil could occur as the...) Residential human post-application exposure to pesticide residues on plants or in soil could occur. Such uses...

40 CFR 158.1060 - Post-application exposure-criteria for testing

Code of Federal Regulations, 2010 CFR

2010-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1060 Post-application exposure...) Occupational human post-application exposure to pesticide residues on plants or in soil could occur as the...) Residential human post-application exposure to pesticide residues on plants or in soil could occur. Such uses...

40 CFR 158.1060 - Post-application exposure-criteria for testing.

Code of Federal Regulations, 2013 CFR

2013-07-01

...) PESTICIDE PROGRAMS DATA REQUIREMENTS FOR PESTICIDES Human Exposure § 158.1060 Post-application exposure...) Occupational human post-application exposure to pesticide residues on plants or in soil could occur as the...) Residential human post-application exposure to pesticide residues on plants or in soil could occur. Such uses...

Air emissions from sour-gas processing plants and dairy-cattle reproduction in Alberta, Canada.

PubMed

Scott, H M; Soskolne, C L; Martin, S W; Shoukri, M M; Lissemore, K D; Coppock, R W; Guidotti, T L

2003-02-15

The dispersion of air pollutants from all 231 licensed sour-gas processing plants in Alberta, Canada, was modeled on a monthly basis over a 10-year period (1985-1994). Exposure estimates for sulfur dioxide (SO(2)-used as a surrogate for exposure to combusted emissions) then were assigned to 1382 provincial dairy farms using a geographical-information system. Individual average and peak exposure for periods prior to each of 15 months of age and conception (four exposure-averaging periods for each of two dispersion models) were estimated for 163,988 primiparous female dairy-cattle between 1986 and 1994. Monthly or annual average farm-site exposure estimates likewise were assigned to associated herd-level data sets for the biologically relevant period of interest for each of three additional reproductive outcomes: monthly herd-average calving interval, stillbirth risk, and twinning risk. In one of the main-effects models, the maximum (i.e., peak) monthly sour-gas exposure experienced by individual-animals from birth to conception was associated with an increased time to first-calving in the very-highest exposure category (hazard ratio=0.86, 95% CI=0.80, 0.92). This equates to a decreased hazard (lambda) of calving (in each month subsequent to 22 months of age) for the highest-exposure animals (lambda=0.170) versus the zero-exposure animals (lambda=0.198) in a model with referent values for agro-ecological region and season of birth. The dose-response was not consistent across the full range of exposure categories. There was significant (P=0.003) interaction of emissions with agro-ecological region. After accounting for the interaction, a more-consistent dose-response was evident for some (but not all) agro-ecological regions. This suggests that any effect of emissions on dairy-heifer reproduction is subject to modification by features of soil type, vegetative cover, and/or climate. The increase in monthly herd-average calving interval on farms exposed to the very-highest levels of emissions appeared quite small and of limited practical importance within the range of expected exposures. There was no association between exposure and the risk for twinning. Herds exposed to higher emissions exhibited a slight decrease in risk for stillbirth.

Personal inhalation exposure to polycyclic aromatic hydrocarbons in urban and rural residents in a typical northern city in China.

PubMed

Duan, X; Wang, B; Zhao, X; Shen, G; Xia, Z; Huang, N; Jiang, Q; Lu, B; Xu, D; Fang, J; Tao, S

2014-10-01

Personal inhalation exposure samples were collected and analyzed for polycyclic aromatic hydrocarbons (PAHs) for 126 selected volunteers during heating and non-heating seasons in a typical northern Chinese city, Taiyuan. Measured personal PAH exposure levels for the urban residents in the heating and non-heating seasons were 690 (540-1051) and 404 (266-544) ng/m(3) , respectively, while, for the rural residents, they were 770 (504-1071) and 312 (201-412) ng/m(3) , respectively. Thus, rural residents are exposed to lower PAH contamination in comparison with the urban residents in the non-heating seasons. In the heating season, personal PAH inhalation exposure levels were comparable between the urban and rural residents, in part owing to the large rate of residential solid fuel consumption in the rural area for household cooking and heating. The estimated incremental lifetime cancer risks (ILCR) due to PAH exposure in Taiyuan were 3.36 × 10(-5) and 2.39 × 10(-5) for the rural and urban residents, respectively, significantly higher than the literature-reported national average level, suggesting an urgent need of PAH pollution control to protect human health. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Promotion of lung adenocarcinoma following inhalation exposure to multi-walled carbon nanotubes

PubMed Central

2014-01-01

Background Engineered carbon nanotubes are currently used in many consumer and industrial products such as paints, sunscreens, cosmetics, toiletries, electronic processes and industrial lubricants. Carbon nanotubes are among the more widely used nanoparticles and come in two major commercial forms, single-walled carbon nanotubes (SWCNT) and the more rigid, multi-walled carbon nanotubes (MWCNT). The low density and small size of these particles makes respiratory exposures likely. Many of the potential health hazards have not been investigated, including their potential for carcinogenicity. We, therefore, utilized a two stage initiation/promotion protocol to determine whether inhaled MWCNT act as a complete carcinogen and/or promote the growth of cells with existing DNA damage. Six week old, male, B6C3F1 mice received a single intraperitoneal (ip) injection of either the initiator methylcholanthrene(MCA, 10 μg/g BW, i.p.), or vehicle (corn oil). One week after i.p. injections, mice were exposed by inhalation to MWCNT (5 mg/m3, 5 hours/day, 5 days/week) or filtered air (controls) for a total of 15 days. At 17 months post-exposure, mice were euthanized and examined for lung tumor formation. Results Twenty-three percent of the filtered air controls, 26.5% of the MWCNT-exposed, and 51.9% of the MCA-exposed mice, had lung bronchiolo-alveolar adenomas and lung adenocarcinomas. The average number of tumors per mouse was 0.25, 0.81 and 0.38 respectively. By contrast, 90.5% of the mice which received MCA followed by MWCNT had bronchiolo-alveolar adenomas and adenocarcinomas with an average of 2.9 tumors per mouse 17months after exposure. Indeed, 62% of the mice exposed to MCA followed by MWCNT had bronchiolo-alveolar adenocarcinomas compared to 13% of the mice that received filtered air, 22% of the MCA-exposed, or 14% of the MWCNT-exposed. Mice with early morbidity resulting in euthanasia had the highest rate of metastatic disease. Three mice exposed to both MCA and MWCNT that were euthanized early had lung adenocarcinoma with evidence of metastasis (5.5%). Five mice (9%) exposed to MCA and MWCNT and 1 (1.6%) exposed to MCA developed serosal tumors morphologically consistent with sarcomatous mesotheliomas, whereas mice administered MWCNT or air alone did not develop similar neoplasms. Conclusions These data demonstrate that some MWCNT exposures promote the growth and neoplastic progression of initiated lung cells in B6C3F1 mice. In this study, the mouse MWCNT lung burden of 31.2 μg/mouse approximates feasible human occupational exposures. Therefore, the results of this study indicate that caution should be used to limit human exposures to MWCNT. PMID:24405760

Exposure to ultrafine particles in different transport modes in the city of Rome.

PubMed

Grana, Mario; Toschi, Nicola; Vicentini, Laura; Pietroiusti, Antonio; Magrini, Andrea

2017-09-01

There is evidence of adverse health impacts from human exposure to particulate air pollution, including increased rates of respiratory and cardiovascular illness, hospitalizations, and pre-mature mortality. Most recent hypotheses assign an important role to ultrafine particles (UFP) (<0.1 μm) and to associated transition metals (in particular Fe). In a large city like Rome, where many active people spend more than one hour per day in private or public transportation, it may be important to evaluate the level of exposure to harmful pollutants which occurs during urban travelling. In this context, the aim of this work was to examine the relative contribution of different transport modes to total daily exposure. We performed experimental measurements during both morning and evening traffic peak hours throughout the winter season (December 2013-March 2014), for a total of 98 trips. Our results suggest that the lowest UFP exposures are experienced by underground train commuters, with an average number concentration of 14 134 cm -3 , and are largely a reflection of the routes being at greater distance from vehicular traffic. Motorcyclists experienced significantly higher average concentrations (73 168 cm -3 ) than all other exposure classes, and this is most likely a result of the presence of high-concentration and short-duration peaks which do not occur when the same routes are traveled by car. UFP concentrations in subway train environments were found to be comparable to urban background levels. Still, in underground trains we found the highest values of PM 10 mass concentration with a maximum value of 422 μg/m 3 . PM 10 concentration in trains was found to be four and two times higher than what was measured in car and motorbike trips, respectively. Transport mode contribution to total integrated UFP daily exposure was found to be 16.3%-20.9% while travelling by car, 28.7% for motorbike trips, and 8.7% for subway trips. Due to lower exposure times, commuting by car and motorbike is comparable to other daily activities in terms of exposure. Our data can provide relevant information for transport decision-making and increase environmental awareness in the hope that the information about inhaled pollutants can translate into a more rational approach to urban travelling. Copyright © 2017 Elsevier Ltd. All rights reserved.

Lack of Sexual Minorities' Rights as a Barrier to HIV Prevention Among Men Who Have Sex with Men and Transgender Women in Asia: A Systematic Review.

PubMed

Anderson, James E; Kanters, Steve

2015-03-01

This study set out to assess the relationship between variation in human rights for sexual minorities in Asian countries and indicators of HIV prevention among men who have sex with men (MSM) and transgender women. To quantitatively measure the relationship between variation in HIV prevention and variation in human rights for sexual minorities, this study developed the Sexual Orientation and Gender Identity (SOGI) Human Rights Index (an original index with scores ranging from 0.0 to 1.0). Subsequently, this study collected 237 epidemiological and behavioral studies from 22 Asian countries and performed a series of meta-analyses in order to calculate national averages for five indicators of HIV prevention: HIV prevalence, inconsistent condom use, recent HIV testing, adequate HIV knowledge, and exposure to HIV prevention services. A change of human rights for sexual minorities from a score of 0.0 to 1.0 as measured by the SOGI Human Rights Index was correlated with a decrease in unprotected anal intercourse by 25.5% (p=0.075), and increases in recent HIV testing by 42.9% (p=0.011), HIV knowledge by 29.5% (p=0.032), and exposure to HIV prevention services by 37.9% (p=0.119). The relationship between HIV prevalence and variation in human rights for sexual minorities was not statistically significant. Our study found correlations between human rights and indicators of HIV prevention, further supporting the need for increased rights among marginalized populations. The paucity of studies from many Asian countries as well as the disparity in how indicators of HIV prevention are measured reveals a need for increased coverage and standardization of MSM serological and behavioral data in order to better inform evidence-based policymaking.

Occurrence of artificial sweeteners in human liver and paired blood and urine samples from adults in Tianjin, China and their implications for human exposure.

PubMed

Zhang, Tao; Gan, Zhiwei; Gao, Chuanzi; Ma, Ling; Li, Yanxi; Li, Xiao; Sun, Hongwen

2016-09-14

In this study, acesulfame (ACE), saccharin (SAC) and cyclamate (CYC) were found in all paired urine and blood samples collected from healthy adults, with mean values of 4070, 918 and 628 ng mL(-1), respectively, in urine and 9.03, 20.4 and 0.72 ng mL(-1), respectively, in blood. SAC (mean: 84.4 ng g(-1)) and CYC (4.29 ng g(-1)) were detectable in all liver samples collected from liver cancer patients, while ACE was less frequently detected. Aspartame (ASP) was not found in any analyzed human sample, which can be explained by the fact that this chemical metabolized rapidly in the human body. Among all adults, significantly positive correlations between SAC and CYC levels were observed (p < 0.001), regardless of human matrices. Nevertheless, no significant correlations between concentrations of SAC (or CYC) and ACE were found in any of the human matrices. Our results suggest that human exposure to SAC and CYC is related, whereas ACE originates from a discrete source. Females (or young adults) were exposed to higher levels of SAC and CYC than males (or elderly). The mean renal clearance of SAC was 730 mL per day per kg in adults, which was significantly (p < 0.001) lower than those for CYC (10 800 mL per day per kg) and ACE (10 300 mL per day per kg). The average total daily intake of SAC and ACE was 9.27 and 33.8 μg per kg bw per day, respectively.

Radon Levels in Indoor Environments of the University Hospital in Bari-Apulia Region Southern Italy

PubMed Central

Fucilli, Fulvio; Cavone, Domenica; De Maria, Luigi; Birtolo, Francesco; Ferri, Giovanni Maria; Soleo, Leonardo

2018-01-01

Since 1988, the International Agency for Research on Cancer (IARC) has classified radon among the compounds for which there is scientific evidence of carcinogenicity for humans (group 1). The World Health Organization (WHO) recommends a reference radon level between 100 and 300 Bq/m3 for homes. The objective of this study is to measure the radon concentrations in 401 workplaces, different from the patient rooms, in 28 different buildings of the university hospital in Bari (Apulia region, Southern Italy) to evaluate the exposure of health care workers. Radon environmental sampling is performed over two consecutive six-month periods via the use of passive dosimeters of the CR-39 type. We find an average annual radon concentration expressed as median value of 48.0 Bq/m3 (range 6.5–388.0 Bq/m3) with a significant difference between the two six-month periods (median value: February/July 41.0 Bq/m3 vs. August/January 55.0 Bq/m3). An average concentration of radon lower than the WHO reference level (100 Bq/m3) is detected in 76.1% of monitored environments, while higher than 300 Bq/m3 only in the 0.9%. Most workplaces report radon concentrations within the WHO reference level, therefore, the risk to workers’ health deriving from occupational exposure to radon can be considered to be low. Nevertheless, the goal is to achieve near-zero exposures to protect workers’ health. PMID:29642436

Cytotoxic and genotoxic potential of drinking water: a comparison between two different concentration methods.

PubMed

Buschini, Annamaria; Giordani, Federica; Pellacani, Claudia; Rossi, Carlo; Poli, Paola

2008-04-01

The level of exposure to hazardous compounds through drinking water is low but it is maintained throughout life, therefore representing a risk factor for human health. The use of techniques averaging the consumer's exposure over time could be more useful than relying on intermittent grab samples that may misrepresent average tap water concentrations due to short-term temporal variability. In this study, we compared the induction of in vitro cytotoxic and genotoxic effects (DNA damage by the comet assay) in relation to different sampling methods, i.e. exposure over time (semipermeable membrane devices, SPMDs, exposed for 30 days) or intermittent grab samples (5 weekly water sampling, C18 concentration). Waters with different chemical characteristics were sampled to test the sensitivity of the two methods. We did not found any positive correlation between the biological findings and water chemical parameters. SPMD extracts induced a significantly greater DNA damage than C18. The different behaviour was specially found for the water samples with a low level of organic compounds and when C18 extracts were highly cytotoxic. Our findings suggest that SPMD could be of a great interest in assessing genotoxic contaminants in both raw and drinking water, with great suitability for continuous monitoring. Furthermore, the results of this study have confirmed the great importance of the biological assays in evaluating the effects of a complex mixture such as water in addition to the conventional chemical examination of water quality.

Particle size distribution and composition in a mechanically ventilated school building during air pollution episodes.

PubMed

Parker, J L; Larson, R R; Eskelson, E; Wood, E M; Veranth, J M

2008-10-01

Particle count-based size distribution and PM(2.5) mass were monitored inside and outside an elementary school in Salt Lake City (UT, USA) during the winter atmospheric inversion season. The site is influenced by urban traffic and the airshed is subject to periods of high PM(2.5) concentration that is mainly submicron ammonium and nitrate. The school building has mechanical ventilation with filtration and variable-volume makeup air. Comparison of the indoor and outdoor particle size distribution on the five cleanest and five most polluted school days during the study showed that the ambient submicron particulate matter (PM) penetrated the building, but indoor concentrations were about one-eighth of outdoor levels. The indoor:outdoor PM(2.5) mass ratio averaged 0.12 and particle number ratio for sizes smaller than 1 microm averaged 0.13. The indoor submicron particle count and indoor PM(2.5) mass increased slightly during pollution episodes but remained well below outdoor levels. When the building was occupied the indoor coarse particle count was much higher than ambient levels. These results contribute to understanding the relationship between ambient monitoring station data and the actual human exposure inside institutional buildings. The study confirms that staying inside a mechanically ventilated building reduces exposure to outdoor submicron particles. This study supports the premise that remaining inside buildings during particulate matter (PM) pollution episodes reduces exposure to submicron PM. New data on a mechanically ventilated institutional building supplements similar studies made in residences.

Polonium in size fractionated mainstream cigarette smoke, predicted deposition and associated internal radiation dose.

PubMed

Tiwari, M; Sahu, S K; Bhangare, R C; Pandit, G G

2016-10-01

In this study, size fractionated mass and 210 Po activity concentrations in mainstream cigarette smoke (MCS) were monitored for three popular cigarette brands. Size segregated collection of MCS was carried out using a cascade type impactor, while mass and 210 Po activity concentration were analyzed gravimetrically and alpha spectrometry (following the radiochemical separation) respectively. Multiple-Path Particle Dosimetry (MPPD V2.11) model is used for prediction of deposition fraction calculations for the MCS deposition in different compartment of human respiratory tract. The activity concentration of 210 Po is founds 10.56 ± 2.46 mBq per cigarette for the tested cigarette brands. 210 Po size distribution indicates most of this associates with fine fraction (Dp < 2.23 μm) of cigarette smoke. The committed annual effective dose to smokers (smoking on an average 20 cigarette a day), considering the 210 Po and 210 Pb concentrations (assuming it is in secular equilibrium with 210 Po) in MCS, was estimated between 0.22 and 0.40 mSv, with mean value of 0.30 mSv for tested cigarette brands. Considering the risk factor of fatal cancer due to radiation exposure of lung (exposure time of 30 years); the average collective estimated fatal cancer risk is estimated as 1.5 × 10 -4 due to 210 Po and 210 Pb exposure to smokers. Copyright © 2016. Published by Elsevier Ltd.

Dietary exposure to acrylamide from potato crisps to the Spanish population.

PubMed

Arribas-Lorenzo, G; Morales, F J

2009-03-01

Potato crisps are one of the food commodities that contribute most to overall dietary human exposure of acrylamide. This investigation has estimated the dietary exposure to acrylamide form potato crisps in the Spanish population. Sampling of potato crisps (n = 36) from 16 different producers were carried out in March 2008. An average level of 740 microg kg(-1) (ranging from 81 to 2622 microg kg(-1); minimum to maximum) and a median of 592 microg kg(-1) were obtained. Acrylamide levels in marketed potato crisps have been significantly reduced (nearly to 50%) compared with a previous sampling performed 4 years earlier. The observed signal value (90th percentile) was 1377 microg kg(-1) with 86% of the samples with acrylamide levels lower than 1000 microg kg(-1). Dietary exposure to acrylamide from potato crisp consumption in the total Spanish population was estimated to be 0.042 microg kg(-1) body weight day(-1) by using a deterministic approach based on the National consumption database. In a second study, dietary exposure (based on a 3-day food record) was determined to be 0.053 microg kg(-1) body weight day(-1) for the adult population (17-60 years) and 0.142 microg kg(-1) body weight day(-1) for children (7-12 years). The contribution of potato crisps to the estimated dietary acrylamide exposure of the Spanish population is moderate as compared with other European Member States.

Spatio-temporal modelling of residential exposure to particulate matter and gaseous pollutants for the Heinz Nixdorf Recall Cohort

NASA Astrophysics Data System (ADS)

Nonnemacher, Michael; Jakobs, Hermann; Viehmann, Anja; Vanberg, Irene; Kessler, Christoph; Moebus, Susanne; Möhlenkamp, Stefan; Erbel, Raimund; Hoffmann, Barbara; Memmesheimer, Michael

2014-07-01

For the simultaneous analysis of short- and long-term effects of air pollution in the Heinz Nixdorf Recall Cohort a sophisticated exposure modelling was performed. The dispersion and chemistry transport model EURAD (European Air Pollution Dispersion) was used for the estimation of hourly concentrations of a number of pollutants for a horizontal grid with a cell size of 1 km² covering the whole study area (three large adjacent cities in a highly urbanized region in Western Germany) for the years 2000-2003 and 2006-2008. For each 1 km² cell we estimated the mean concentration by calculating daily means from the hourly concentrations modelled by the EURAD process. The modelled concentrations showed an overall tendency to decrease from 2001 to 2008 whereas the trend in the single grid cells and study period was inhomogeneous. Participant-related exposure slightly increased from 2001 to 2003 followed by a decrease from 2006 to 2008. The exposure modelling enables a very flexible exposure assessment compared to conventional modelling approaches which either use central monitoring or temporally static spatial contrasts. The modelling allows the calculation of an average exposure concentration for any place and time within the study region and study period with a high spatial and temporal resolution. This is important for the assessment of short-, medium and long-term effects of air pollution on human health in epidemiological studies.

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

PubMed

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

2017-03-04

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

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

PubMed Central

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

2017-01-01

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

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

NASA Astrophysics Data System (ADS)

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

2017-04-01

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

Validation and comparison of two sampling methods to assess dermal exposure to drilling fluids and crude oil.

PubMed

Galea, Karen S; McGonagle, Carolyn; Sleeuwenhoek, Anne; Todd, David; Jiménez, Araceli Sánchez

2014-06-01

Dermal exposure to drilling fluids and crude oil is an exposure route of concern. However, there have been no published studies describing sampling methods or reporting dermal exposure measurements. We describe a study that aimed to evaluate a wipe sampling method to assess dermal exposure to an oil-based drilling fluid and crude oil, as well as to investigate the feasibility of using an interception cotton glove sampler for exposure on the hands/wrists. A direct comparison of the wipe and interception methods was also completed using pigs' trotters as a surrogate for human skin and a direct surface contact exposure scenario. Overall, acceptable recovery and sampling efficiencies were reported for both methods, and both methods had satisfactory storage stability at 1 and 7 days, although there appeared to be some loss over 14 days. The methods' comparison study revealed significantly higher removal of both fluids from the metal surface with the glove samples compared with the wipe samples (on average 2.5 times higher). Both evaluated sampling methods were found to be suitable for assessing dermal exposure to oil-based drilling fluids and crude oil; however, the comparison study clearly illustrates that glove samplers may overestimate the amount of fluid transferred to the skin. Further comparison of the two dermal sampling methods using additional exposure situations such as immersion or deposition, as well as a field evaluation, is warranted to confirm their appropriateness and suitability in the working environment. © The Author 2014. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.

The Human Exposure Model (HEM): A Tool to Support Rapid Assessment of Human Health Impacts from Near-Field Consumer Product Exposures

EPA Science Inventory

The US EPA is developing an open and publically available software program called the Human Exposure Model (HEM) to provide near-field exposure information for Life Cycle Impact Assessments (LCIAs). Historically, LCIAs have often omitted impacts from near-field sources of exposur...

Spatiotemporal distributions of ambient oxides of nitrogen, with implications for exposure inequality and urban design.

PubMed

Yu, Haofei; Stuart, Amy L

2013-08-01

Intra-urban differences in concentrations of oxides of nitrogen (NO(x)) and exposure disparities in the Tampa area were investigated across temporal scales through emissions estimation, dispersion modeling, and analysis of residential subpopulation exposures. A hybrid estimation method was applied to provide link-level hourly on-road mobile source emissions. Ambient concentrations in 2002 at 1 km resolution were estimated using the CALPUFF dispersion model. Results were combined with residential demographic data at the block-group level, to investigate exposures and inequality for select racioethnic, age, and income population subgroups. Results indicate that on-road mobile sources contributed disproportionately to ground-level concentrations and dominated the spatial footprint across temporal scales (annual average to maximum hour). The black, lower income (less than $40K annually), and Hispanic subgroups had higher estimated exposures than the county average; the white and higher income (greater than $60K) subgroups had lower than average exposures. As annual average concentration increased, the disparity between groups generally increased. However for the highest 1-hr concentrations, reverse disparities were also found. Current studies of air pollution exposure inequality have not fully considered differences by time scale and are often limited in spatial resolution. The modeling methods and the results presented here can be used to improve understanding of potential impacts of urban growth form on health and to improve urban sustainability. Results suggest focusing urban design interventions on reducing on-road mobile source emissions in areas with high densities of minority and low income groups.

Smoke exposure at western wildfires.

Treesearch

Timothy E. Reinhardt; Roger D. Ottmar

2000-01-01

Smoke exposure measurements among firefighters at wildfires in the Western United States between 1992 and 1995 showed that altogether most exposures were not significant, between 3 and 5 percent of the shift-average exposures exceeded occupational exposure limits for carbon monoxide and respiratory irritants. Exposure to benzene and total suspended particulate was not...

Global risk of radioactive fallout after nuclear reactor accidents

NASA Astrophysics Data System (ADS)

Lelieveld, J.; Kunkel, D.; Lawrence, M. G.

2011-11-01

Reactor core meltdowns of nuclear power plants are rare, yet the consequences are catastrophic. But what is meant by "rare"? And what can be learned from the Chernobyl and Fukushima incidents? Here we assess the risk of exposure to radioactivity due to atmospheric dispersion of gases and particles following severe nuclear accidents, using particulate 137Cs and gaseous 131I as proxies for the fallout. It appears that previously the occurrence of major accidents and the risks of radioactive contamination have been underestimated. Using a global model of the atmosphere we compute that on average, in the event of a core melt of any nuclear power plant worldwide, more than 90% of emitted 137Cs would be transported beyond 50km and about 50% beyond 1000 km distance. This corroborates that such accidents have large-scale and trans-boundary impacts. Although the emission strengths and atmospheric removal processes of 137Cs and 131I are quite different, the radioactive contamination patterns over land and the human deposition exposure are computed to be similar. High human exposure risks occur around reactors in densely populated regions, notably in southern Asia where a core melt can subject 55 million people to radioactive contamination. The recent decision by Germany to phase out its nuclear reactors will reduce the national risk, though a large risk will still remain from the reactors in neighbouring countries.

Global risk of radioactive fallout after nuclear reactor accidents

NASA Astrophysics Data System (ADS)

Kunkel, D.; Lelieveld, J.; Lawrence, M. G.

2012-04-01

Reactor core meltdowns of nuclear power plants are rare, yet the consequences are catastrophic. But what is meant by "rare"? And what can be learned from the Chernobyl and Fukushima incidents? Here we assess the risk of exposure to radioactivity due to atmospheric dispersion of gases and particles following severe nuclear accidents, using particulate 137Cs and gaseous 131I as proxies for the fallout. It appears that previously the occurrence of major accidents and the risks of radioactive contamination have been underestimated. Using a global model of the atmosphere we compute that on average, in the event of a core melt of any nuclear power plant worldwide, more than 90 % of emitted 137Cs would be transported beyond 50 km and about 50 % beyond 1000 km distance. This corroborates that such accidents have large-scale and trans-boundary impacts. Although the emission strengths and atmospheric removal processes of 137Cs and 131I are quite different, the radioactive contamination patterns over land and the human deposition exposure are computed to be similar. High human exposure risks occur around reactors in densely populated regions, notably in southern Asia where a core melt can subject 55 million people to radioactive contamination. The recent decision by Germany to phase out its nuclear reactors will reduce the national risk, though a large risk will still remain from the reactors in neighbouring countries.

A study of classroom acoustics and school teachers' noise exposure, voice load and speaking time during teaching, and the effects on vocal and mental fatigue development.

PubMed

Kristiansen, Jesper; Lund, Søren Peter; Persson, Roger; Shibuya, Hitomi; Nielsen, Per Møberg; Scholz, Matthias

2014-11-01

The study investigated the noise exposure in a group of Danish school teachers. The aims were to investigate if noise posed a risk of impairment of hearing and to study the association between classroom acoustical conditions, noise exposure, vocal symptoms, and cognitive fatigue. Background noise levels, vocal load and speaking time were measured on 35 teachers during actual classroom teaching. The classrooms were characterized acoustically by measurements of reverberation time. Before and after the workday, the teachers answered a questionnaire on fatigue symptoms and carried out two cognitive test tasks sensitive to mental fatigue. The average noise level during the lessons was 72 dB(A), but during indoor sports activities the average noise level increased 6.6 dB(A). Room reverberation time (range 0.39-0.83 s) had no significant effect on the noise level. The teachers were talking with a raised voice in 61% of the time, and the vocal load increased 0.65 dB(A) per dB(A) increase in the average lesson noise level. An increase in voice symptoms during the workday correlated significantly with individual average noise exposure, and a decrease in performance in the two-back test correlated significantly with individual average vocal load. Noise exposure in general classrooms posed no risk of noise-induced hearing impairment in school teachers. However, the results provide evidence for an association between noise exposure and vocal load and development of vocal symptoms and cognitive fatigue after work.

Instrumental Variable Analysis with a Nonlinear Exposure–Outcome Relationship

PubMed Central

Davies, Neil M.; Thompson, Simon G.

2014-01-01

Background: Instrumental variable methods can estimate the causal effect of an exposure on an outcome using observational data. Many instrumental variable methods assume that the exposure–outcome relation is linear, but in practice this assumption is often in doubt, or perhaps the shape of the relation is a target for investigation. We investigate this issue in the context of Mendelian randomization, the use of genetic variants as instrumental variables. Methods: Using simulations, we demonstrate the performance of a simple linear instrumental variable method when the true shape of the exposure–outcome relation is not linear. We also present a novel method for estimating the effect of the exposure on the outcome within strata of the exposure distribution. This enables the estimation of localized average causal effects within quantile groups of the exposure or as a continuous function of the exposure using a sliding window approach. Results: Our simulations suggest that linear instrumental variable estimates approximate a population-averaged causal effect. This is the average difference in the outcome if the exposure for every individual in the population is increased by a fixed amount. Estimates of localized average causal effects reveal the shape of the exposure–outcome relation for a variety of models. These methods are used to investigate the relations between body mass index and a range of cardiovascular risk factors. Conclusions: Nonlinear exposure–outcome relations should not be a barrier to instrumental variable analyses. When the exposure–outcome relation is not linear, either a population-averaged causal effect or the shape of the exposure–outcome relation can be estimated. PMID:25166881

Assessment of exposures and potential risks to the US adult population from wear (attrition and abrasion) of gold and ceramic dental restorations.

PubMed

Richardson, G Mark; Clemow, Scott R; Peters, Rachel E; James, Kyle J; Siciliano, Steven D

2016-01-01

Little has been published on the chemical exposures and risks of dental restorative materials other than from dental amalgam and composite resins. Here we provide the first exposure and risk assessment for gold (Au) alloy and ceramic restorative materials. Based on the 2001-2004 US National Health and Nutrition Examination Survey (NHANES), we assessed the exposure of US adults to the components of Au alloy and ceramic dental restorations owing to dental material wear. Silver (Ag) is the most problematic component of Au alloy restorations, owing to a combination of toxicity and proportional composition. It was estimated that adults could possess an average of four tooth surfaces restored with Au alloy before exceeding, on average, the reference exposure level (REL) for Ag. Lithium (Li) is the most problematic component of dental ceramics. It was estimated that adults could possess an average of 15 tooth surfaces restored with ceramics before exceeding the REL for Li. Relative risks of chemical exposures from dental materials decrease in the following order: Amalgam>Au alloys>ceramics>composite resins.

Effects of whole-body exposure to 915 MHz RFID on secretory functions of the thyroid system in rats.

PubMed

Kim, Hye Sun; Paik, Man-Jeong; Kim, Yeon Ju; Lee, Gwang; Lee, Yun-Sil; Choi, Hyung-Do; Kim, Byung Chan; Pack, Jeong-Ki; Kim, Nam; Ahn, Young Hwan

2013-10-01

As a part of an investigation on the potential risks of radiofrequency identification (RFID) on human health, we studied whether exposure to 915 MHz RFID in rats significantly affected the secretory function of the thyroid system. A reverberation chamber was used as a whole-body exposure system. Male Sprague-Dawley rats were exposed for 8 h per day, 5 days per week, for a duration of 2, 4, 8, or 16 weeks. The estimated whole-body average specific absorption rate (SAR) varied from 3.2 to 4.6 W/kg depending on the age/mass of the animals for the field of the 915 MHz RFID reader. Plasma levels of triiodothyronine (T3), thyroxine (T4), and thyroid-stimulating hormone (TSH) were evaluated via enzyme-linked immunosorbent assay. Morphological changes in the thyroid gland were then analyzed. No changes in T3, T4, or TSH were observed over time between the sham- and RFID-exposed groups. We suggest that subchronic exposure to 915 MHz RFID at a SAR of 4 W/kg does not cause significant effects on thyroid secretory function. © 2013 Wiley Periodicals, Inc.

Spatiotemporal Characteristics and Health Risk Assessment of Heavy Metals in PM2.5 in Zhejiang Province

PubMed Central

Wang, Xiaofeng; He, Shengliang; Chen, Shuchang; Zhang, Yongli; Wang, Aihong; Luo, Jinbin; Ye, Xialiang; Mo, Zhe; Wu, Lizhi; Xu, Peiwei; Cai, Gaofeng; Chen, Zhijian; Lou, Xiaoming

2018-01-01

The spatiotemporal characteristics and human health risks of 12 heavy metals (Al, As, Be, Cd, Cr, Hg, Mn, Ni, Pb, Sb, Se, and Tl) in fine particulate matter (PM2.5) in Zhejiang Province were investigated. The annual average PM2.5 concentration was 58.83 µg/m3 in 2015 in Zhejiang. Element contents in PM2.5 varied greatly with the season and locations. Al, Pb, and Mn were the most abundant elements among the studied metal(loid)s in PM2.5. The non-carcinogenic risks of the 12 elements through inhalation and dermal contact exposure were lower than the safe level for children and adults. However, there were potential non-carcinogenic risks of Tl, As, and Sb for children and Tl for adults through ingestion exposure. The carcinogenic risks from As, Be, Cd, Cr, Pb, and Ni through inhalation exposure were less than the acceptable level (1 × 10−4) for children and adults. Pb may carry a potential carcinogenic risk for both children and adults through ingestion. More attention should be paid to alleviate non-carcinogenic and carcinogenic health risks posed by particle-bound toxic elements through ingestion exposure. PMID:29587346

Contribution of the in-vehicle microenvironment to individual ambient-source nitrogen dioxide exposure: the Multi-Ethnic Study of Atherosclerosis and Air Pollution.

PubMed

Hazlehurst, Marnie F; Spalt, Elizabeth W; Nicholas, Tyler P; Curl, Cynthia L; Davey, Mark E; Burke, Gregory L; Watson, Karol E; Vedal, Sverre; Kaufman, Joel D

2018-06-01

Exposure estimates that do not account for time in-transit may underestimate exposure to traffic-related air pollution, but exact contributions have not been studied directly. We conducted a 2-week monitoring, including novel in-vehicle sampling, in a subset of the Multi-Ethnic Study of Atherosclerosis and Air Pollution cohort in two cities. Participants spent the majority of their time indoors and only 4.4% of their time (63 min/day) in-vehicle, on average. The mean ambient-source NO 2 concentration was 5.1 ppb indoors and 32.3 ppb in-vehicle during drives. On average, indoor exposure contributed 69% and in-vehicle exposure contributed 24% of participants' ambient-source NO 2 exposure. For participants in the highest quartile of time in-vehicle (≥1.3 h/day), indoor and in-vehicle contributions were 60 and 31%, respectively. Incorporating infiltrated indoor and measured in-vehicle NO 2 produced exposure estimates 5.6 ppb lower, on average, than using only outdoor concentrations. The indoor microenvironment accounted for the largest proportion of ambient-source exposure in this older population, despite higher concentrations of NO 2 outdoors and in vehicles than indoors. In-vehicle exposure was more influential among participants who drove the most and for participants residing in areas with lower outdoor air pollution. Failure to characterize exposures in these microenvironments may contribute to exposure misclassification in epidemiologic studies.

Health effects of gasoline exposure. I. Exposure assessment for U.S. distribution workers.

PubMed Central

Smith, T J; Hammond, S K; Wong, O

1993-01-01

Personal exposures were estimated for a large cohort of workers in the U.S. domestic system for distributing gasoline by trucks and marine vessels. This assessment included development of a rationale and methodology for extrapolating vapor exposures prior to the availability of measurement data, analysis of existing measurement data to estimate task and job exposures during 1975-1985, and extrapolation of truck and marine job exposures before 1975. A worker's vapor exposure was extrapolated from three sets of factors: the tasks in his or her job associated with vapor sources, the characteristics of vapor sources (equipment and other facilities) at the work site, and the composition of petroleum products producing vapors. Historical data were collected on the tasks in job definitions, on work-site facilities, and on product composition. These data were used in a model to estimate the overall time-weighted-average vapor exposure for jobs based on estimates of task exposures and their duration. Task exposures were highest during tank filling in trucks and marine vessels. Measured average annual, full-shift exposures during 1975-1985 ranged from 9 to 14 ppm of total hydrocarbon vapor for truck drivers and 2 to 35 ppm for marine workers on inland waterways. Extrapolated past average exposures in truck operations were highest for truck drivers before 1965 (range 140-220 ppm). Other jobs in truck operations resulted in much lower exposures. Because there were few changes in marine operations before 1979, exposures were assumed to be the same as those measured during 1975-1985. Well-defined exposure gradients were found across jobs within time periods, which were suitable for epidemiologic analyses. PMID:8020436

OVERVIEW OF THE U.S. EPA NERL'S HUMAN EXPOSURE MODELING

EPA Science Inventory

Computational modeling of human exposure to environmental pollutants is one of the primary activities of the US Environmental Protection Agency's National Exposure Research Laboratory (NERL). Assessment of human exposures is a critical part of the overall risk assessment para...

Personal exposures to PM 2.5 and their relationships with microenvironmental concentrations

NASA Astrophysics Data System (ADS)

Lim, Soogil; Kim, Jeonghoon; Kim, Taehyun; Lee, Kiyoung; Yang, Wonho; Jun, Sangil; Yu, Seungdo

2012-02-01

Personal exposure to particulate matter of aerodynamic diameters less than 2.5 μm (PM 2.5) can be affected by various factors. The purpose of this study was to determine the impact of activity pattern and the contribution of each microenvironment to personal PM 2.5 exposure. Technicians carried a nephelometer for PM 2.5 while engaging in scripted time location activities. The scripted activities of 10 different population groups were based on time activity patterns of the Seoul population in Korea. A total of 58 daily PM 2.5 personal exposures were available for analysis. The average PM 2.5 personal exposure was 19.8 ± 15.3 μg m -3. The average personal exposure of each population group ranged from 9.8 to 43.1 μg m -3. High peak and average concentrations were observed in restaurants and bars; such high concentrations were due to secondhand smoke and cooking with charcoal on tables. The residential indoor level of the nine microenvironments was the largest contributor to personal exposure. The contributions from residential indoor, non-residential indoor, transportation, and outdoor levels were 36.2%, 53.4%, 6.7%, and 3.7%, respectively. The contributions of microenvironments varied among population groups; these variations suggest that the impact of activity pattern on personal exposure is significant.

Comparison of average global exposure of population induced by a macro 3G network in different geographical areas in France and Serbia.

PubMed

Huang, Yuanyuan; Varsier, Nadège; Niksic, Stevan; Kocan, Enis; Pejanovic-Djurisic, Milica; Popovic, Milica; Koprivica, Mladen; Neskovic, Aleksandar; Milinkovic, Jelena; Gati, Azeddine; Person, Christian; Wiart, Joe

2016-09-01

This article is the first thorough study of average population exposure to third generation network (3G)-induced electromagnetic fields (EMFs), from both uplink and downlink radio emissions in different countries, geographical areas, and for different wireless device usages. Indeed, previous publications in the framework of exposure to EMFs generally focused on individual exposure coming from either personal devices or base stations. Results, derived from device usage statistics collected in France and Serbia, show a strong heterogeneity of exposure, both in time, that is, the traffic distribution over 24 h was found highly variable, and space, that is, the exposure to 3G networks in France was found to be roughly two times higher than in Serbia. Such heterogeneity is further explained based on real data and network architecture. Among those results, authors show that, contrary to popular belief, exposure to 3G EMFs is dominated by uplink radio emissions, resulting from voice and data traffic, and average population EMF exposure differs from one geographical area to another, as well as from one country to another, due to the different cellular network architectures and variability of mobile usage. Bioelectromagnetics. 37:382-390, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Cytostatic response of NB69 cells to weak pulse-modulated 2.2 GHz radar-like signals.

PubMed

Trillo, María A; Cid, María Antonia; Martínez, Maria Antonia; Page, Juan E; Esteban, Jaime; Úbeda, Alejandro

2011-07-01

The present study investigates the response of two human cancer cell lines to a 24-h treatment with a 2.2-GHz, pulse-modulated (5 µs pulse duration, 100 Hz repetition rate) radar-like signal at an average SAR = 0.023 W/kg, using a newly designed setup for in vitro exposure to radiofrequency (RF) fields. A complete discretized model of the setup was created for numerical dosimetry using finite-difference time-domain (FDTD) software, SEMCAD X. The average dose of RF radiation absorbed by the cultures was calculated to be subthermal (ΔT < 0.1 °C). The RF exposure induced a consistent, statistically significant reduction in the cell number (13.5% below controls, P < 0.001) in the neuroblastoma NB69 line. This effect was accompanied with slight but statistically significant increases in the proportions of cells in phases G0/G1 and G2/M of the cell cycle (6% and 9%, respectively; P < 0.05 over controls). By contrast, the hepatocarcinoma cell line HepG2 did not respond to the same RF treatment. These results indicate that a pulse-modulated RF radiation with high instantaneous amplitude and low average power can induce cytostatic responses on specific, sensitive cancer cell lines. The effect would be mediated, at least in part, by alterations in the kinetics of the cell cycle. Copyright © 2011 Wiley-Liss, Inc.

Air pollution dispersion models for human exposure predictions in London.

PubMed

Beevers, Sean D; Kitwiroon, Nutthida; Williams, Martin L; Kelly, Frank J; Ross Anderson, H; Carslaw, David C

2013-01-01

The London household survey has shown that people travel and are exposed to air pollutants differently. This argues for human exposure to be based upon space-time-activity data and spatio-temporal air quality predictions. For the latter, we have demonstrated the role that dispersion models can play by using two complimentary models, KCLurban, which gives source apportionment information, and Community Multi-scale Air Quality Model (CMAQ)-urban, which predicts hourly air quality. The KCLurban model is in close agreement with observations of NO(X), NO(2) and particulate matter (PM)(10/2.5), having a small normalised mean bias (-6% to 4%) and a large Index of Agreement (0.71-0.88). The temporal trends of NO(X) from the CMAQ-urban model are also in reasonable agreement with observations. Spatially, NO(2) predictions show that within 10's of metres of major roads, concentrations can range from approximately 10-20 p.p.b. up to 70 p.p.b. and that for PM(10/2.5) central London roadside concentrations are approximately double the suburban background concentrations. Exposure to different PM sources is important and we predict that brake wear-related PM(10) concentrations are approximately eight times greater near major roads than at suburban background locations. Temporally, we have shown that average NO(X) concentrations close to roads can range by a factor of approximately six between the early morning minimum and morning rush hour maximum periods. These results present strong arguments for the hybrid exposure model under development at King's and, in future, for in-building models and a model for the London Underground.

Human health risk assessment: A case study involving heavy metal soil contamination after the flooding of the river Meuse during the winter of 1993-1994.

PubMed Central

Albering, H J; van Leusen, S M; Moonen, E J; Hoogewerff, J A; Kleinjans, J C

1999-01-01

At the end of December 1993 and also at the end of January 1995, the river Meuse, one of the major rivers in Europe, flooded and river banks were inundated. We investigated the possible health risks of exposure to heavy metal concentrations in river bank soils resulting from the flooding of the river Meuse at the end of 1993. Soil and deposit samples and corresponding aerable and fodder crops were collected and analyzed for heavy metals. Although the soils of the floodplain of the river Meuse appeared severely polluted mainly by Cd and Zn, the heavy metal concentrations in the crops grown on these soils were within background ranges. Incidentally, the legal standard for Cd as endorsed by the Commodities Act was exceeded in wheat crops. The main exposure pathways for the general population were through the consumption of food crops grown on the river banks and through the direct ingestion of contaminated soils. For estimating potential human exposure in relation to soil pollution, we used a multiple pathway exposure model. For estimating the actual risk, we determined metal contents of vegetables grown in six experimental gardens. From this study, it can be concluded that there is a potential health risk for the river bank inhabitants as a consequence of Pb and Cd contaminations of the floodplain soils of the river Meuse, which are frequently inundated (averaged flooding frequency once every 2 years). Images Figure 1 Figure 2 PMID:9872715

Occupational exposure to electric fields and induced currents associated with 400 kV substation tasks from different service platforms.

PubMed

Korpinen, Leena H; Elovaara, Jarmo A; Kuisti, Harri A

2011-01-01

The aim of the study was to investigate the occupational exposure to electric fields, average current densities, and average total contact currents at 400 kV substation tasks from different service platforms (main transformer inspection, maintenance of operating device of disconnector, maintenance of operating device of circuit breaker). The average values are calculated over measured periods (about 2.5 min). In many work tasks, the maximum electric field strengths exceeded the action values proposed in the EU Directive 2004/40/EC, but the average electric fields (0.2-24.5 kV/m) were at least 40% lower than the maximum values. The average current densities were 0.1-2.3 mA/m² and the average total contact currents 2.0-143.2 µA, that is, clearly less than the limit values of the EU Directive. The average values of the currents in head and contact currents were 16-68% lower than the maximum values when we compared the average value from all cases in the same substation. In the future it is important to pay attention to the fact that the action and limit values of the EU Directive differ significantly. It is also important to take into account that generally, the workers' exposure to the electric fields, current densities, and total contact currents are obviously lower if we use the average values from a certain measured time period (e.g., 2.5 min) than in the case where exposure is defined with only the help of the maximum values. © 2010 Wiley-Liss, Inc.

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

EPA Science Inventory

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

AN APPROACH TO METHODS DEVELOPMENT FOR HUMAN EXPOSURE ASSESSMENT STUDIES

EPA Science Inventory

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

Concentration-response of short-term ozone exposure and hospital admissions for asthma in Texas.

PubMed

Zu, Ke; Liu, Xiaobin; Shi, Liuhua; Tao, Ge; Loftus, Christine T; Lange, Sabine; Goodman, Julie E

2017-07-01

Short-term exposure to ozone has been associated with asthma hospital admissions (HA) and emergency department (ED) visits, but the shape of the concentration-response (C-R) curve is unclear. We conducted a time series analysis of asthma HAs and ambient ozone concentrations in six metropolitan areas in Texas from 2001 to 2013. Using generalized linear regression models, we estimated the effect of daily 8-hour maximum ozone concentrations on asthma HAs for all ages combined, and for those aged 5-14, 15-64, and 65+years. We fit penalized regression splines to evaluate the shape of the C-R curves. Using a log-linear model, estimated risk per 10ppb increase in average daily 8-hour maximum ozone concentrations was highest for children (relative risk [RR]=1.047, 95% confidence interval [CI]: 1.025-1.069), lower for younger adults (RR=1.018, 95% CI: 1.005-1.032), and null for older adults (RR=1.002, 95% CI: 0.981-1.023). However, penalized spline models demonstrated significant nonlinear C-R relationships for all ages combined, children, and younger adults, indicating the existence of thresholds. We did not observe an increased risk of asthma HAs until average daily 8-hour maximum ozone concentrations exceeded approximately 40ppb. Ozone and asthma HAs are significantly associated with each other; susceptibility to ozone is age-dependent, with children at highest risk. C-R relationships between average daily 8-hour maximum ozone concentrations and asthma HAs are significantly curvilinear for all ages combined, children, and younger adults. These nonlinear relationships, as well as the lack of relationship between average daily 8-hour maximum and peak ozone concentrations, have important implications for assessing risks to human health in regulatory settings. Copyright © 2017. Published by Elsevier Ltd.

Influence of Class V preparation on in vivo temperature rise in anesthetized human pulp during exposure to a Polywave® LED light curing unit.

PubMed

Zarpellon, Driellen Christine; Runnacles, Patrício; Maucoski, Cristiane; Gross, Dayane Jaqueline; Coelho, Ulisses; Rueggeberg, Frederick Allen; Arrais, Cesar Augusto Galvão

2018-06-01

This in vivo study evaluated pulp temperature (PT) rise in human premolars having deep Class V preparations during exposure to a light curing unit (LCU) using selected exposure modes (EMs). After local Ethics Committee approval, intact first premolars (n=8) requiring extraction for orthodontic reasons, from 8 volunteers, received infiltrative and intraligamental anesthesia and were isolated using rubber dam. A minute pulp exposure was attained and sterile probe from a wireless, NIST-traceable, temperature acquisition system was inserted into the coronal pulp chamber to continuously monitor PT (°C). A deep buccal Class V preparation was prepared using a high speed diamond bur under air-water spray cooling. The surface was exposed to a Polywave ® LED LCU (Bluephase 20i, Ivoclar Vivadent) using selected EMs, allowing 7-min span between each exposure: 10-s in low (10-s/L), 10-s (10-s/H), 30-s (30-s/H), or 60-s (60-s/H) in high mode; and 5-s-Turbo (5-s/T). Peak PT values and PT increases over physiologic baseline levels (ΔT) were subjected to 1-way, repeated measures ANOVAs, and Bonferroni's post-hoc tests (α=0.05). Linear regression analysis was performed to establish the relationship between applied radiant exposure and ΔT. All EMs produced higher peak PT than the baseline temperature (p<0.001). Only 60-s/H mode generated an average ΔT of 5.5°C (p<0.001). A significant, positive relationship was noted between applied radiant exposure and ΔT (r 2 =0.8962; p<0.001). In vivo exposure of deep Class V preparation to Polywave ® LED LCU increases PT to values considered safe for the pulp, for most EMs. Only the longest evaluated EM caused higher PT increase than the critical ΔT, thought to be associated with pulpal necrosis. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Inc. All rights reserved.

Derivation of an occupational exposure limit for an inhalation analgesic methoxyflurane (Penthrox(®)).

PubMed

Frangos, John; Mikkonen, Antti; Down, Christin

2016-10-01

Methoxyflurane (MOF) a haloether, is an inhalation analgesic agent for emergency relief of pain by self administration in conscious patients with trauma and associated pain. It is administered under supervision of personnel trained in its use. As a consequence of supervised use, intermittent occupational exposure can occur. An occupational exposure limit has not been established for methoxyflurane. Human clinical and toxicity data have been reviewed and used to derive an occupational exposure limit (referred to as a maximum exposure level, MEL) according to modern principles. The data set for methoxyflurane is complex given its historical use as anaesthetic. Distinguishing clinical investigations of adverse health effects following high and prolonged exposure during anaesthesia to assess relatively low and intermittent exposure during occupational exposure requires an evidence based approach to the toxicity assessment and determination of a critical effect and point of departure. The principal target organs are the kidney and the central nervous system and there have been rare reports of hepatotoxicity, too. Methoxyflurane is not genotoxic based on in vitro bacterial mutation and in vivo micronucleus tests and it is not classifiable (IARC) as a carcinogenic hazard to humans. The critical effect chosen for development of a MEL is kidney toxicity. The point of departure (POD) was derived from the concentration response relationship for kidney toxicity using the benchmark dose method. A MEL of 15 ppm (expressed as an 8 h time weighted average (TWA)) was derived. The derived MEL is at least 50 times higher than the mean observed TWA (0.23 ppm) for ambulance workers and medical staff involved in supervising use of Penthrox. In typical treatment environments (ambulances and treatment rooms) that meet ventilation requirements the derived MEL is at least 10 times higher than the modelled TWA (1.5 ppm or less) and the estimated short term peak concentrations are within the MEL. The odour threshold for MOF of 0.13-0.19 ppm indicates that the odour is detectable well below the MEL. Given the above considerations the proposed MEL is health protective. Copyright © 2016 The Author(s). Published by Elsevier Inc. All rights reserved.

Time Averaged Transmitter Power and Exposure to Electromagnetic Fields from Mobile Phone Base Stations

PubMed Central

Bürgi, Alfred; Scanferla, Damiano; Lehmann, Hugo

2014-01-01

Models for exposure assessment of high frequency electromagnetic fields from mobile phone base stations need the technical data of the base stations as input. One of these parameters, the Equivalent Radiated Power (ERP), is a time-varying quantity, depending on communication traffic. In order to determine temporal averages of the exposure, corresponding averages of the ERP have to be available. These can be determined as duty factors, the ratios of the time-averaged power to the maximum output power according to the transmitter setting. We determine duty factors for UMTS from the data of 37 base stations in the Swisscom network. The UMTS base stations sample contains sites from different regions of Switzerland and also different site types (rural/suburban/urban/hotspot). Averaged over all regions and site types, a UMTS duty factor F ≈ 0.32 ± 0.08 for the 24 h-average is obtained, i.e., the average output power corresponds to about a third of the maximum power. We also give duty factors for GSM based on simple approximations and a lower limit for LTE estimated from the base load on the signalling channels. PMID:25105551

Heating of tissues by microwaves: a model analysis.

PubMed

Foster, K R; Lozano-Nieto, A; Riu, P J; Ely, T S

1998-01-01

We consider the thermal response times for heating of tissue subject to nonionizing (microwave or infrared) radiation. The analysis is based on a dimensionless form of the bioheat equation. The thermal response is governed by two time constants: one (tau1) pertains to heat convection by blood flow, and is of the order of 20-30 min for physiologically normal perfusion rates; the second (tau2) characterizes heat conduction and varies as the square of a distance that characterizes the spatial extent of the heating. Two idealized cases are examined. The first is a tissue block with an insulated surface, subject to irradiation with an exponentially decreasing specific absorption rate, which models a large surface area of tissue exposed to microwaves. The second is a hemispherical region of tissue exposed at a spatially uniform specific absorption rate, which models localized exposure. In both cases, the steady-state temperature increase can be written as the product of the incident power density and an effective time constant tau(eff), which is defined for each geometry as an appropriate function of tau1 and tau2. In appropriate limits of the ratio of these time constants, the local temperature rise is dominated by conductive or convective heat transport. Predictions of the block model agree well with recent data for the thresholds for perception of warmth or pain from exposure to microwave energy. Using these concepts, we developed a thermal averaging time that might be used in standards for human exposure to microwave radiation, to limit the temperature rise in tissue from radiation by pulsed sources. We compare the ANSI exposure standards for microwaves and infrared laser radiation with respect to the maximal increase in tissue temperature that would be allowed at the maximal permissible exposures. A historical appendix presents the origin of the 6-min averaging time used in the microwave standard.

Electromagnetic Field Effect or Simply Stress? Effects of UMTS Exposure on Hippocampal Longterm Plasticity in the Context of Procedure Related Hormone Release

PubMed Central

Ladage, Kerstin; Krause-Finkeldey, Dorothee; El Ouardi, Abdessamad; Bitz, Andreas; Streckert, Joachim; Hansen, Volkert; Dermietzel, Rolf

2011-01-01

Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded. PMID:21573218

Assessment of the biological effects of welding fumes emitted from metal inert gas welding processes of aluminium and zinc-plated materials in humans.

PubMed

Hartmann, L; Bauer, M; Bertram, J; Gube, M; Lenz, K; Reisgen, U; Schettgen, T; Kraus, T; Brand, P

2014-03-01

The aim of this study was to investigate biological effects and potential health risks due to two different metal-inert-gas (MIG) welding fumes (MIG welding of aluminium and MIG soldering of zinc coated steel) in healthy humans. In a threefold cross-over design study 12 male subjects were exposed to three different exposure scenarios. Exposures were performed under controlled conditions in the Aachener Workplace Simulation Laboratory (AWSL). On three different days the subjects were either exposed to filtered ambient air, to welding fumes from MIG welding of aluminium, or to fumes from MIG soldering of zinc coated materials. Exposure was performed for 6 h and the average fume concentration was 2.5 mg m(-3). Before, directly after, 1 day after, and 7 days after exposure spirometric and impulse oscillometric measurements were performed, exhaled breath condensate (EBC) was collected and blood samples were taken and analyzed for inflammatory markers. During MIG welding of aluminium high ozone concentrations (up to 250 μg m(-3)) were observed, whereas ozone was negligible for MIG soldering. For MIG soldering, concentrations of high-sensitivity CRP (hsCRP) and factor VIII were significantly increased but remained mostly within the normal range. The concentration of neutrophils increased in tendency. For MIG welding of aluminium, the lung function showed significant decreases in Peak Expiratory Flow (PEF) and Mean Expiratory Flow at 75% vital capacity (MEF 75) 7 days after exposure. The concentration of ristocetin cofactor was increased. The observed increase of hsCRP during MIG-soldering can be understood as an indicator for asymptomatic systemic inflammation probably due to zinc (zinc concentration 1.5 mg m(-3)). The change in lung function observed after MIG welding of aluminium may be attributed to ozone inhalation, although the late response (7 days after exposure) is surprising. Copyright © 2013 Elsevier GmbH. All rights reserved.

Brain magnetic resonance imaging and manganese concentrations in red blood cells of smelting workers: Search for biomarkers of manganese exposure

PubMed Central

Jiang, Yueming; Zheng, Wei; Long, Liling; Zhao, Weijia; Li, Xiangrong; Mo, Xuean; Lu, Jipei; Fu, Xue; Li, Wenmei; Liu, Shouting; Long, Quanyong; Huang, Jinli; Pira, Enrico

2014-01-01

The MRI technique has been used in diagnosis of manganism in humans and non-human primates. This cross-sectional study was designed to explore whether the pallidal signal intensity in T1-weighted MRI correlated with Mn levels in the blood compartment among Mn-exposed workers and to understand to what extent the MRI signal could reflect Mn exposure. A group of 18 randomly selected male Mn-exposed workers of which 13 were smelting workers with high exposure (mean of airborne Mn in work place: 1.26 mg/m3; range: 0.31–2.93 mg/m3), and 5 power distribution control workers with low exposure (0.66 mg/m3 and 0.23–0.77 mg/m3) from a ferroalloy factory, and another group of 9 male subjects as controls from a non-smelting factory who were office or cafeteria workers (0.01 mg/m3 and 0–0.03 mg/m3) were recruited for neurological tests, MRI examination, and analysis of Mn in whole blood (MnB), plasma (MnP) or red blood cells (MnRBC). No clinical symptoms and signs of manganism were observed among these workers. MRI data showed average increases of 7.4% (p < 0.05) and 16.1% (p < 0.01) in pallidal index (PI) among low- and high-exposed workers, respectively, as compared to controls. Fourteen out of 18 Mn-exposed workers (78%) had intensified PI values, while this proportion was even higher (85%) among the high Mn-exposed workers. Among exposed workers, the PI values were significantly associated with MnRBC (r = 0.55, p = 0.02). Our data suggest that the workers exposed to airborne Mn, but without clinical symptoms, display an exposure-related, intensified MRI signal. The MRI, as well as MnRBC, may be useful in early diagnosis of Mn exposure. PMID:16978697

Brain magnetic resonance imaging and manganese concentrations in red blood cells of smelting workers: search for biomarkers of manganese exposure.

PubMed

Jiang, Yueming; Zheng, Wei; Long, Liling; Zhao, Weijia; Li, Xiangrong; Mo, Xuean; Lu, Jipei; Fu, Xue; Li, Wenmei; Liu, Shouting; Long, Quanyong; Huang, Jinli; Pira, Enrico

2007-01-01

The MRI technique has been used in diagnosis of manganism in humans and non-human primates. This cross-sectional study was designed to explore whether the pallidal signal intensity in T1-weighted MRI correlated with Mn levels in the blood compartment among Mn-exposed workers and to understand to what extent the MRI signal could reflect Mn exposure. A group of 18 randomly selected male Mn-exposed workers of which 13 were smelting workers with high exposure (mean of airborne Mn in work place: 1.26 mg/m3; range: 0.31-2.93 mg/m3), and 5 power distribution control workers with low exposure (0.66 mg/m3 and 0.23-0.77 mg/m3) from a ferroalloy factory, and another group of 9 male subjects as controls from a non-smelting factory who were office or cafeteria workers (0.01 mg/m3 and 0-0.03 mg/m3) were recruited for neurological tests, MRI examination, and analysis of Mn in whole blood (MnB), plasma (MnP) or red blood cells (MnRBC). No clinical symptoms and signs of manganism were observed among these workers. MRI data showed average increases of 7.4% (p<0.05) and 16.1% (p<0.01) in pallidal index (PI) among low- and high-exposed workers, respectively, as compared to controls. Fourteen out of 18 Mn-exposed workers (78%) had intensified PI values, while this proportion was even higher (85%) among the high Mn-exposed workers. Among exposed workers, the PI values were significantly associated with MnRBC (r=0.55, p=0.02). Our data suggest that the workers exposed to airborne Mn, but without clinical symptoms, display an exposure-related, intensified MRI signal. The MRI, as well as MnRBC, may be useful in early diagnosis of Mn exposure.

Measures for curtailment of iatrogenic exposure. Guide to correct x-ray examinations (in Japanese)

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

Misonoo, K.

1973-08-01

Of the coposure dose for humans from various radiation sources, introgenic exposure amounts to 1/2 to twice the natural radiation source. Although the mechanism of induction of malignant tumor by radiation is not clanified, it is evident that it is induced after receiving a dose above 100 rads. However, the presence of a threshold, under which it does not develop, is unknown. Tabulated were ICRP's calculations on the degree of risk of injury and the estimated values of genetic injury due to 1 rad. In order to estimate the harmful effect of exposure in x-ray diagnosis, the dose in themore » critical tissue of the human body and the types and the frequency of radiation examinations are important. The judgment of genetic injury is expressed by the genetically significant dose, which is calculated from the dose in the genital gland received by individuals. The impcrtant criterion for the judgment of physical injury is the mean annual dose per person in the marrow (mean dose in the red marrow). The dose in the genital organ is important as the dose related to the evaluation of the degree of genetic risk. The characteristics of iatrogenic exposure are partial and acute exposure and a high dose rate. Tabulated individually were the frequency of x-ray examinations, the mean dose in the genital organ according urce. The radiation dose during x-ray pelvimetry to 51 patients was estimated, and the cytogenetic response of peripheral lymphocytes was determined in 25 of their newborn babies. The calculations resulted in an average midline fetal dose of 1,035 and 1,860 mrads for the patients receiving 2 projections and more than 2 projections, respectively. There was no evidence of radioinduced chromosomal darnage in the newborn infants following x-ray exposure in utero. (auth)« less

Role of Neprilysin in Airway Inflammation Induced by Diesel Exhaust Emissions

PubMed Central

Wong, Simon S.; Sun, Nina N.; Fastje, Cynthia D.; Witten, Mark L.; Lantz, R. Clark; Lu, Bao; Sherrill, Duane L.; Gerard, Craig J.; Burgess, Jefferey L.

2016-01-01

In this study, we examined the role of neprilysin (NEP*), a key membrane-bound endopeptidase, in the inflammatory response induced by diesel exhaust emissions (DEE) in the airways through a number of approaches: in vitro, animal, and controlled human exposure. Our specific aims were (1) to examine the role of NEP in inflammatory injury induced by diesel exhaust particles (DEP) using Nep-intact (wild-type) and Nep-null mice; (2) to examine which components of DEP are associated with NEP downregulation in vitro; (3) to determine the molecular impact of DEP exposure and decreased NEP expression on airway epithelial cells’ gene expression in vitro, using a combination of RNA interference (RNAi) and microarray approaches; and (4) to evaluate the effects on NEP activity of human exposure to DEE. We report four main results: First, we found that exposure of normal mice to DEP consisting of standard reference material (SRM) 2975 via intratracheal installation can downregulate NEP expression in a concentration-dependent manner. The changes were accompanied by increases in the number of macrophages and epithelial cells, as well as proinflammatory cytokines, examined in bronchoalveolar lavage (BAL) fluid and cells. Nep-null mice displayed increased and/or additional inflammatory responses when compared with wild-type mice, especially in response to exposure to the higher dose of DEP that we used. These in vivo findings suggest that loss of NEP in mice could cause increased susceptibility to injury or exacerbate inflammatory responses after DEP exposure via release of specific cytokines from the lungs. Second, we found evidence, using in vitro studies, that downregulation of NEP by DEP in cultured human epithelial BEAS-2B cells was mostly attributable to DEP-adsorbed organic compounds, whereas the carbonaceous core and transition metal components of DEP had little or no effect on NEP messenger RNA (mRNA) expression. This NEP downregulation was not a specific response to DEP or its contents because the change also occurred after exposure to urban dust (SRM 1649a), which differs in physical and chemical composition from DEP. Third, we also collected the transcriptome profiles of the cells through a 2 × 3 factorial design. DEP exposure upregulated 151 genes and downregulated 59 genes. Cells with decreased NEP expression (accomplished by transfecting an NEP-specific small interfering RNA [siRNA]) substantially altered the expression of genes (upregulating 17 and downregulating 14) associated with DNA/protein binding, calcium channel activities, and the cascade of intracellular signaling by cytokines. Data generated from the combined RNAi and microarray approaches revealed that there is a complex molecular cascade mediated by NEP in different subcellular compartments, possibly influencing the inflammatory response. Fourth, in a controlled human exposure study, we observed significant increases in soluble NEP in sputum after acute exposure to DEE, with an average net increase of 31%. We speculate that the change in NEP activity in sputum, if confirmed in larger epidemiologic investigations at ambient exposure levels to DEE, may provide a useful endpoint and promote insight into the mechanism of DEE-induced airway alterations. PMID:21877416

AC field exposure study: human exposure to 60-Hz electric fields

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

Silva, J.M.

1985-04-01

The objective of this study was to develop a method of estimating human exposure to the 60 Hz electric fields created by transmission lines. The Activity Systems Model simulates human activities in a variety of situations where exposure to electric fields is possible. The model combines maps of electric fields, activity maps, and experimentally determined activity factors to provide histograms of time spent in electric fields of various strengths in the course of agricultural, recreational, and domestic activities. For corroboration, the study team measured actual human exposure at locations across the United States near transmission lines ranging in voltage frommore » 115 to 1200 kV. The data were collected with a specially designed vest that measures exposure. These data demonstrate the accuracy of the exposure model presented in this report and revealed that most exposure time is spent in fields of magnitudes similar to many household situations. The report provides annual exposure estimates for human activities near transmission lines and in the home and compares them with exposure data from typical laboratory animal experiments. For one exposure index, the cumulative product of time and electric field, exposure during some of the laboratory animal experiments is two to four orders of magnitude greater than cumulative exposure for a human during one year of outdoor work on a farm crossed by a transmission line.« less

Evaluation of Background Exposures of Americans to Dioxin-Like Compounds in the 1990's and the 2000's

USDA-ARS?s Scientific Manuscript database

The US Environmental Protection Agency’s 2004 Dioxin Reassessment included a characterization of background exposures to dioxin-like compounds, including an estimate of an average background intake dose and an average background body burden. These quantities were derived from data generated in the m...

Lead concentration in meat from lead-killed moose and predicted human exposure using Monte Carlo simulation.

PubMed

Lindboe, M; Henrichsen, E N; Høgåsen, H R; Bernhoft, A

2012-01-01

Lead-based hunting ammunitions are still common in most countries. On impact such ammunition releases fragments which are widely distributed within the carcass. In Norway, wild game is an important meat source for segments of the population and 95% of hunters use lead-based bullets. In this paper, we have investigated the lead content of ground meat from moose (Alces alces) intended for human consumption in Norway, and have predicted human exposure through this source. Fifty-two samples from different batches of ground meat from moose killed with lead-based bullets were randomly collected. The lead content was measured by atomic absorption spectroscopy. The lead intake from exposure to moose meat over time, depending on the frequency of intake and portion size, was predicted using Monte Carlo simulation. In 81% of the batches, lead levels were above the limit of quantification of 0.03 mg kg(-1), ranging up to 110 mg kg(-1). The mean lead concentration was 5.6 mg kg(-1), i.e. 56 times the European Commission limit for lead in meat. For consumers eating a moderate meat serving (2 g kg(-1) bw), a single serving would give a lead intake of 11 µg kg(-1) bw on average, with maximum of 220 µg kg(-1) bw. Using Monte Carlo simulation, the median (and 97.5th percentile) predicted weekly intake of lead from moose meat was 12 µg kg(-1) bw (27 µg kg(-1) bw) for one serving per week and 25 µg kg(-1) bw (45 µg kg(-1) bw) for two servings per week. The results indicate that the intake of meat from big game shot with lead-based bullets imposes a significant contribution to the total human lead exposure. The provisional tolerable weekly intake set by the World Health Organization (WHO) of 25 µg kg(-1) bw is likely to be exceeded in people eating moose meat on a regular basis. The European Food Safety Authority (EFSA) has recently concluded that adverse effects may be present at even lower exposure doses. Hence, even occasional consumption of big game meat with lead levels as those found in the present study may imply an increased risk for adverse health effects. Children and women of child-bearing age are of special concern due to the neurodevelopmental effects of lead.

Impact of Orientation on the Vitamin D Weighted Exposure of a Human in an Urban Environment.

PubMed

Schrempf, Michael; Thuns, Nadine; Lange, Kezia; Seckmeyer, Gunther

2017-08-16

The vitamin D₃-weighted UV exposure of a human with vertical posture was calculated for urban locations to investigate the impact of orientation and obstructions on the exposure. Human exposure was calculated by using the 3D geometry of a human and integrating the radiance, i.e., the radiant energy from the direct solar beam and the diffuse sky radiation from different incident and azimuth angles. Obstructions of the sky are derived from hemispherical images, which are recorded by a digital camera with a fisheye lens. Due to the low reflectivity of most surfaces in the UV range, the radiance from obstructed sky regions was neglected. For spring equinox (21 March), the exposure of a human model with winter clothing in an environment where obstructions cover 40% of the sky varies by up to 25%, depending on the orientation of the human model to the sun. The calculation of the accumulated vitamin D₃-weighted exposure of a human with winter clothing walking during lunch break shows that human exposure is reduced by the obstruction of buildings and vegetation by 40%.

Design and dosimetric analysis of a 385 MHz TETRA head exposure system for use in human provocation studies.

PubMed

Schmid, Gernot; Bolz, Thomas; Uberbacher, Richard; Escorihuela-Navarro, Ana; Bahr, Achim; Dorn, Hans; Sauter, Cornelia; Eggert, Torsten; Danker-Hopfe, Heidi

2012-10-01

A new head exposure system for double-blind provocation studies investigating possible effects of terrestrial trunked radio (TETRA)-like exposure (385 MHz) on central nervous processes was developed and dosimetrically analyzed. The exposure system allows localized exposure in the temporal brain, similar to the case of operating a TETRA handset at the ear. The system and antenna concept enables exposure during wake and sleep states while an electroencephalogram (EEG) is recorded. The dosimetric assessment and uncertainty analysis yield high efficiency of 14 W/kg per Watt of accepted antenna input power due to an optimized antenna directly worn on the subject's head. Beside sham exposure, high and low exposure at 6 and 1.5 W/kg (in terms of maxSAR10g in the head) were implemented. Double-blind control and monitoring of exposure is enabled by easy-to-use control software. Exposure uncertainty was rigorously evaluated using finite-difference time-domain (FDTD)-based computations, taking into account anatomical differences of the head, the physiological range of the dielectric tissue properties including effects of sweating on the antenna, possible influences of the EEG electrodes and cables, variations in antenna input reflection coefficients, and effects on the specific absorption rate (SAR) distribution due to unavoidable small variations in the antenna position. This analysis yielded a reasonable uncertainty of <±45% (max to min ratio of 4.2 dB) in terms of maxSAR10g in the head and a variability of <±60% (max to min ratio of 6 dB) in terms of mass-averaged SAR in different brain regions, as demonstrated by a brain region-specific absorption analysis. Copyright © 2012 Wiley Periodicals, Inc.

HEDS - EPA DATABASE SYSTEM FOR PUBLIC ACCESS TO HUMAN EXPOSURE DATA

EPA Science Inventory

Human Exposure Database System (HEDS) is an Internet-based system developed to provide public access to human-exposure-related data from studies conducted by EPA's National Exposure Research Laboratory (NERL). HEDS was designed to work with the EPA Office of Research and Devel...

THE HUMAN EXPOSURE DATABASE SYSTEM (HEDS)-PUTTING THE NHEXAS DATA ON-LINE

EPA Science Inventory

The EPA's National Exposure Research Laboratory (NERL) has developed an Internet accessible Human Exposure Database System (HEDS) to provide the results of NERL human exposure studies to both the EPA and the external scientific communities. The first data sets that will be ava...

Temporal trends of PM10 and its impact on mortality in Lombardy, Italy.

PubMed

Carugno, Michele; Consonni, Dario; Bertazzi, Pier Alberto; Biggeri, Annibale; Baccini, Michela

2017-08-01

Exposure to particulate matter with diameter ≤10 μm (PM 10 ) entails well documented adverse effects on human health. In the last decade, concentration of PM 10 in Lombardy (10 million inhabitants), Italy, has been gradually decreasing. We evaluated how the mortality burden due to PM 10 varied in that same period. We focused on 13 areas of the Region in 2003-2014: 11 cities with more than 50,000 inhabitants, 1 smaller alpine town and 1 agricultural province. For each area, we collected PM 10 annual average concentrations and natural mortality data, and we used the posterior area-specific effects from a previous Bayesian meta-analysis to estimate the short-term impact of PM 10 on mortality, in terms of deaths attributable (AD) to annual average exposures exceeding the WHO threshold of 20 μg/m 3 . PM 10 annual average values showed a non-homogenous decreasing trend in the investigated time period in most of the areas. Overall, the population-weighted exposure levels decreased, except for a peak in 2011, but never met the WHO threshold. In 2003-2006, PM 10 levels were responsible, on average, for 343.0 annual AD from natural causes that decreased to 253.5 in 2007-2010 and to 208.3 in 2011-2014. Overall we estimated that PM 10 was responsible for about 1% of all natural deaths (min-max range: 0.86%-1.42%); the impact was heterogeneous among areas. By collecting routinely available data for the most populated areas in Lombardy, we returned a picture of air pollution and health trends in the last decade. Notwithstanding the observed reduction in PM 10 between 2003 and 2014 and the resulting decline in the number of AD, the impact is still relevant. Hence, appropriate policies for emission reduction could have a further beneficial effect on population health. Studies based on routine data and local effect estimates are recommended to properly inform the policy-making process. Copyright © 2017 Elsevier Ltd. All rights reserved.

Extension of Oxygen Tolerance in Man. Predictive Studies 6.

DTIC Science & Technology

1991-12-31

maintained on Ziegler rat and mouse diet were used in these -12- i exposures. Average weights of the different exposure groups ranged from about 300...end of oxygen exposure were associated with reciprocal changes in end-tidal PCO 2 . Average PCO 2 (N=7) decreased significantly from 40.8 mm Hg during... PCO 2 (N=6) increased from 30.8 to 36.2 mm Hg. An increased frequency of breathing with a related reduction in tidal volume was found near the end of

Second harmonic generation microscopy of the living human cornea

NASA Astrophysics Data System (ADS)

Artal, Pablo; Ávila, Francisco; Bueno, Juan

2018-02-01

Second Harmonic Generation (SHG) microscopy provides high-resolution structural imaging of the corneal stroma without the need of labelling techniques. This powerful tool has never been applied to living human eyes so far. Here, we present a new compact SHG microscope specifically developed to image the structural organization of the corneal lamellae in living healthy human volunteers. The research prototype incorporates a long-working distance dry objective that allows non-contact three-dimensional SHG imaging of the cornea. Safety assessment and effectiveness of the system were firstly tested in ex-vivo fresh eyes. The maximum average power of the used illumination laser was 20 mW, more than 10 times below the maximum permissible exposure (according to ANSI Z136.1-2000). The instrument was successfully employed to obtain non-contact and non-invasive SHG of the living human eye within well-established light safety limits. This represents the first recording of in vivo SHG images of the human cornea using a compact multiphoton microscope. This might become an important tool in Ophthalmology for early diagnosis and tracking ocular pathologies.

40 CFR 158.250 - Experimental use permit data requirements for human exposure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Experimental use permit data requirements for human exposure. 158.250 Section 158.250 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for human exposure. No data for applicator exposure and post...

40 CFR 158.250 - Experimental use permit data requirements for human exposure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Experimental use permit data requirements for human exposure. 158.250 Section 158.250 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for human exposure. No data for applicator exposure and post...

40 CFR 158.250 - Experimental use permit data requirements for human exposure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Experimental use permit data requirements for human exposure. 158.250 Section 158.250 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for human exposure. No data for applicator exposure and post...

40 CFR 158.250 - Experimental use permit data requirements for human exposure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Experimental use permit data requirements for human exposure. 158.250 Section 158.250 Protection of Environment ENVIRONMENTAL PROTECTION... Experimental use permit data requirements for human exposure. No data for applicator exposure and post...

Perspectives of comparing risks of environmental carcinogens

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

Perera, F.; Boffetta, P.

1988-10-19

In 1987, investigators concluded that the risks of man-made industrial carcinogens and pesticides (outside of the workplace) are trivial compared with the risks of naturally occurring carcinogens found mostly in the diet. They used a ranking system based on human exposure and rodent potency (HERP) data to arrive at this conclusion. As a result, they recommend that regulatory agencies, such as the Environmental Protection Agency and the Food and Drug Administration, base their priorities in this area on their HERP system. We analyzed the assumptions and data set upon which the HERPs were based, concluding that such a simplified approachmore » to set public health policy is inappropriate given the underlying uncertainties. However, we note that when comparisons are consistently based on estimates of average daily exposure to common carcinogens, the HERP scores of many man-made pollutants are comparable to those of naturally occurring carcinogens in the diet.158 references.« less

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in coastal waters of northern South China Sea.

PubMed

Wang, Xuefeng; Wang, Lifei; Jia, Xiaoping; Jackson, Donald A

2017-09-01

Long-term spatiotemporal trends and health risk assessment of oyster arsenic levels in the coastal waters of northern South China Sea were investigated in order to help improve the quality and safety control and sustainable aquaculture for mollusks in China. Cultured oysters (Crassostrea rivularis) collected from the waters of 23 bays, harbors, and estuaries along the coast of northern South China Sea from 1989 to 2012 were examined for spatial patterns and long-term temporal trends of oyster arsenic levels. Single-factor index and health risk assessment were used to quantify arsenic exposure to human health through oyster consumption. Overall, arsenic was detected in 97.4% of the oyster samples, and oyster arsenic levels were non-detectable-2.51 mg/kg with an average of 0.63 ± 0.54 mg/kg. Oyster arsenic levels in the coastal waters of northern South China Sea showed an overall decline from 1989 to 2012, remained relatively low since 2005, and slightly increased after 2007. Oyster arsenic levels in Guangdong coastal waters were much higher with more variation than in Guangxi and Hainan coastal waters, and the long-term trends of oyster arsenic levels in Guangdong coastal waters dominated the overall trends of oyster arsenic levels in the coastal waters of northern South China Sea. Within Guangdong Province, oyster arsenic levels were highest in east Guangdong coastal waters, followed by the Pearl River estuary and west Guangdong coastal waters. Single-factor index ranged between 0.27 and 0.97, and average health risk coefficient was 3.85 × 10 -5 , both suggesting that oyster arsenic levels in northern South China Sea are within the safe range for human consumption. However, long-term attention should be given to seafood market monitoring in China and the risk of arsenic exposure to human health through oyster consumption.

Arsenic accumulation in rice (Oryza sativa L.): human exposure through food chain.

PubMed

Azizur Rahman, M; Hasegawa, H; Mahfuzur Rahman, M; Mazid Miah, M A; Tasmin, A

2008-02-01

Although human exposure to arsenic is thought to be caused mainly through arsenic-contaminated underground drinking water, the use of this water for irrigation enhances the possibility of arsenic uptake into crop plants. Rice is the staple food grain in Bangladesh. Arsenic content in straw, grain and husk of rice is especially important since paddy fields are extensively irrigated with underground water having high level of arsenic concentration. However, straw and husk are widely used as cattle feed. Arsenic concentration in rice grain was 0.5+/-0.02 mg kg(-1) with the highest concentrations being in grains grown on soil treated with 40 mg As kg(-1) soil. With the average rice consumption between 400 and 650 g/day by typical adults in the arsenic-affected areas of Bangladesh, the intake of arsenic through rice stood at 0.20-0.35 mg/day. With a daily consumption of 4 L drinking water, arsenic intake through drinking water stands at 0.2mg/day. Moreover, when the rice plant was grown in 60 mg of As kg(-1) soil, arsenic concentrations in rice straw were 20.6+/-0.52 at panicle initiation stage and 23.7+/-0.44 at maturity stage, whereas it was 1.6+/-0.20 mg kg(-1) in husk. Cattle drink a considerable amount of water. So alike human beings, arsenic gets deposited into cattle body through rice straw and husk as well as from drinking water which in turn finds a route into the human body. Arsenic intake in human body from rice and cattle could be potentially important and it exists in addition to that from drinking water. Therefore, a hypothesis has been put forward elucidating the possible food chain pathways through which arsenic may enter into human body.

A physiologically based in silico model for trans-2-hexenal detoxification and DNA adduct formation in human including interindividual variation indicates efficient detoxification and a negligible genotoxicity risk.

PubMed

Kiwamoto, R; Spenkelink, A; Rietjens, I M C M; Punt, A

2013-09-01

A number of α,β-unsaturated aldehydes are present in food both as natural constituents and as flavouring agents. Their reaction with DNA due to their electrophilic α,β-unsaturated aldehyde moiety may result in genotoxicity as observed in some in vitro models, thereby raising a safety concern. A question that remains is whether in vivo detoxification would be efficient enough to prevent DNA adduct formation and genotoxicity. In this study, a human physiologically based kinetic/dynamic (PBK/D) model of trans-2-hexenal (2-hexenal), a selected model α,β-unsaturated aldehyde, was developed to examine dose-dependent detoxification and DNA adduct formation in humans upon dietary exposure. The kinetic model parameters for detoxification were quantified using relevant pooled human tissue fractions as well as tissue fractions from 11 different individual subjects. In addition, a Monte Carlo simulation was performed so that the impact of interindividual variation in 2-hexenal detoxification on the DNA adduct formation in the population as a whole could be examined. The PBK/D model revealed that DNA adduct formation due to 2-hexenal exposure was 0.039 adducts/10⁸ nucleotides (nt) at the estimated average 2-hexenal dietary intake (0.04 mg 2-hexenal/kg bw) and 0.18 adducts/10⁸ nt at the 95th percentile of the dietary intake (0.178 mg 2-hexenal/kg bw) in the most sensitive people. These levels are three orders of magnitude lower than natural background DNA adduct levels that have been reported in disease-free humans (6.8-110 adducts/10⁸ nt), suggesting that the genotoxicity risk for the human population at realistic dietary daily intakes of 2-hexenal may be negligible.

In Utero Bisphenol A Concentration, Metabolism, and Global DNA Methylation Across Matched Placenta, Kidney, and Liver in the Human Fetus

PubMed Central

Nahar, Muna S.; Liao, Chunyang; Kannan, Kurunthachalam; Harris, Craig; Dolinoy, Dana C.

2014-01-01

While urine has been an easily accessible and feasible matrix for human biomonitoring, analytical measurements in internal tissues and organs can provide more accurate exposure assessments to understand disease etiology. This is especially important for the endocrine active compound, bisphenol A (BPA), where studies investigating internal doses at sensitive periods of human development are currently lacking. Herein, BPA concentrations, BPA-specific metabolizing enzyme gene expression, and global DNA methylation were characterized across three matched tissues from elective pregnancy terminations of 2nd trimester human fetuses: the placenta, liver, and kidney (N=12 each; N=36 total). Compared to liver (free: 0.54-50.5 ng/g), BPA concentrations were lower in matched placenta (<0.05-25.4 ng/g) and kidney (0.08-11.1 ng/g) specimens. BPA-specific metabolism gene expression of GUSB, UGT2B15, STS, and SULT1A1 differed across each tissue type; however, conjugation and deconjugation expression patterns were similar across the fetus. Average LINE1 and CCGG global methylation were 58.3 and 59.2% in placenta, 79.5 and 66.4% in fetal liver, and 77.9 and 77.0% in fetal kidney, with significant tissue-specific DNA methylation differences in both LINE1 (p-value <0.001) and CCGG content (p-value <0.001). Total BPA concentrations were positively associated with global methylation for the placenta only using the LINE1 assay (p-value: 0.002), suggesting organ-specific biological effects after fetal exposure. Utilizing sensitive human clinical specimens, results are informative for BPA toxicokinetics and toxicodynamics assessment in the developing human fetus. PMID:25434263

Nuclear translocation and DNA-binding activity of NFKB (NF-kappaB) after exposure of human monocytes to pulsed ultra-wideband electromagnetic fields (1 kV/cm) fails to transactivate kappaB-dependent gene expression.

PubMed

Natarajan, M; Nayak, B K; Galindo, C; Mathur, S P; Roldan, F N; Meltz, M L

2006-06-01

The objective of this study was to investigate whether exposure of human monocytes to a pulsed ultra-wideband electromagnetic field (EMF) of 1 kV/cm average peak power triggers a signaling pathway responsible for the transcriptional regulation of NFKB (NF-kappaB)-dependent gene expression. Human Mono Mac 6 (MM6) cells were exposed intermittently to EMF pulses for a total of 90 min. The pulse width was 0.79+/-0.01 ns and the pulse repetition rate was 250 pps. The temperature of the medium was maintained at 37 degrees C in both sham- and EMF-exposed flasks. Total NFKB DNA-binding activity was measured in the nuclear extracts by the electrophoretic mobility shift assay. Cells exposed to the EMFs and incubated for 24 h postexposure showed a 3.5+/-0.2-fold increase in the NFKB DNA-binding activity. Since activation of NFKB was observed, the possibility of kappaB-dependent gene expression in response to exposure to the EMFs was investigated using NFKB signal-specific gene arrays. The results revealed no difference in the NFKB-dependent gene expression profiles at 8 or 24 h postexposure, indicating that activated NFKB does not lead to the differential expression of kappaB-dependent target genes. To determine whether the absence of the kappaB-dependent gene expression was due to compromised transcriptional regulation of NFKB, the functional activity of NFKB was examined in cells transiently transfected with Mercury Pathway constructs containing 4x NFKB binding sites associated either with the luciferase reporter system or a control vector. Pulsed EMF exposure did not induce NFKB-driven luciferase activity in these cells, indicating that the activation of NFKB at 24 h after the 1 kV/cm EMF exposure is functionally inactive. From these results, it is clear that the EMF-induced NFKB activation is only a transient response, with minimal or no downstream effect.

Survey of residential 50 Hz EMF exposure from transformer stations.

PubMed

Szabó, Judit; Jánossy, Gábor; Thuróczy, György

2007-01-01

In Hungary it is typical that 10/04 kV transformer stations are being installed in multistory residential and office buildings. Magnetic fields (MFs) up to several tens of microT have been measured in apartments close to transformers. The aim of the present study was to provide systematic assessment of MF exposure of residents living above transformer stations. Out of 41 addresses provided by the electricity supplier, current load of 21 transformers and MF in 21 apartments was measured. Spot MFs at 1 m height and time weighted average 24 h MF exposure at bed height was measured. All-day personal MF exposure was measured at waist and HOME exposure was calculated. BED exposure was measured at bed height. Participants kept a time-activity diary. The time-weighted average 24 h MF exposure (3.03 microT) exceeded the usual residential exposure (<0.2 microT). The mean HOME and BED personal exposure above transformers was 0.825 and 1.033 microT, respectively. Our study provides exposure assessment of a cohort with a wider exposure range, compared to power-line epidemiological studies.

Microplastic fragments and microbeads in digestive tracts of planktivorous fish from urban coastal waters.

PubMed

Tanaka, Kosuke; Takada, Hideshige

2016-09-30

We investigated microplastics in the digestive tracts of 64 Japanese anchovy (Engraulis japonicus) sampled in Tokyo Bay. Plastic was detected in 49 out of 64 fish (77%), with 2.3 pieces on average and up to 15 pieces per individual. All of the plastics were identified by Fourier transform infrared spectroscopy. Most were polyethylene (52.0%) or polypropylene (43.3%). Most of the plastics were fragments (86.0%), but 7.3% were beads, some of which were microbeads, similar to those found in facial cleansers. Eighty percent of the plastics ranged in size from 150 μm to 1000 μm, smaller than the reported size range of floating microplastics on the sea surface, possibly because the subsurface foraging behavior of the anchovy reflected the different size distribution of plastics between surface waters and subsurface waters. Engraulis spp. are important food for many humans and other organisms around the world. Our observations further confirm that microplastics have infiltrated the marine ecosystem, and that humans may be exposed to them. Because microplastics retain hazardous chemicals, increase in fish chemical exposure by the ingested plastics is of concern. Such exposure should be studied and compared with that in the natural diet.

Microplastic fragments and microbeads in digestive tracts of planktivorous fish from urban coastal waters

NASA Astrophysics Data System (ADS)

Tanaka, Kosuke; Takada, Hideshige

2016-09-01

We investigated microplastics in the digestive tracts of 64 Japanese anchovy (Engraulis japonicus) sampled in Tokyo Bay. Plastic was detected in 49 out of 64 fish (77%), with 2.3 pieces on average and up to 15 pieces per individual. All of the plastics were identified by Fourier transform infrared spectroscopy. Most were polyethylene (52.0%) or polypropylene (43.3%). Most of the plastics were fragments (86.0%), but 7.3% were beads, some of which were microbeads, similar to those found in facial cleansers. Eighty percent of the plastics ranged in size from 150 μm to 1000 μm, smaller than the reported size range of floating microplastics on the sea surface, possibly because the subsurface foraging behavior of the anchovy reflected the different size distribution of plastics between surface waters and subsurface waters. Engraulis spp. are important food for many humans and other organisms around the world. Our observations further confirm that microplastics have infiltrated the marine ecosystem, and that humans may be exposed to them. Because microplastics retain hazardous chemicals, increase in fish chemical exposure by the ingested plastics is of concern. Such exposure should be studied and compared with that in the natural diet.

Effects of Chronic Central Arginine Vasopressin (AVP) on Maternal Behavior in Chronically Stressed Rat Dams

PubMed Central

Coverdill, Alexander J.; McCarthy, Megan; Bridges, Robert S.; Nephew, Benjamin C.

2012-01-01

Exposure of mothers to chronic stressors during pregnancy or the postpartum period often leads to the development of depression, anxiety, or other related mood disorders. The adverse effects of mood disorders are often mediated through maternal behavior and recent work has identified arginine vasopressin (AVP) as a key neuropeptide hormone in the expression of maternal behavior in both rats and humans. Using an established rodent model that elicits behavioral and physiological responses similar to human mood disorders, this study tested the effectiveness of chronic AVP infusion as a novel treatment for the adverse effects of exposure to chronic social stress during lactation in rats. During early (day 3) and mid (day 10) lactation, AVP treatment significantly decreased the latency to initiate nursing and time spent retrieving pups, and increased pup grooming and total maternal care (sum of pup grooming and nursing). AVP treatment was also effective in decreasing maternal aggression and the average duration of aggressive bouts on day 3 of lactation. Central AVP may be an effective target for the development of treatments for enhancing maternal behavior in individuals exposed to chronic social stress. PMID:24349762

Mobile phone radiation causes changes in gene and protein expression in human endothelial cell lines and the response seems to be genome- and proteome-dependent.

PubMed

Nylund, Reetta; Leszczynski, Dariusz

2006-09-01

We have examined in vitro cell response to mobile phone radiation (900 MHz GSM signal) using two variants of human endothelial cell line: EA.hy926 and EA.hy926v1. Gene expression changes were examined in three experiments using cDNA Expression Arrays and protein expression changes were examined in ten experiments using 2-DE and PDQuest software. Obtained results show that gene and protein expression were altered, in both examined cell lines, in response to one hour mobile phone radiation exposure at an average specific absorption rate of 2.8 W/kg. However, the same genes and proteins were differently affected by the exposure in each of the cell lines. This suggests that the cell response to mobile phone radiation might be genome- and proteome-dependent. Therefore, it is likely that different types of cells and from different species might respond differently to mobile phone radiation or might have different sensitivity to this weak stimulus. Our findings might also explain, at least in part, the origin of discrepancies in replication studies between different laboratories.

Human biodistribution and radiation dosimetry of 82Rb.

PubMed

Senthamizhchelvan, Srinivasan; Bravo, Paco E; Esaias, Caroline; Lodge, Martin A; Merrill, Jennifer; Hobbs, Robert F; Sgouros, George; Bengel, Frank M

2010-10-01

Prior estimates of radiation-absorbed doses from (82)Rb, a frequently used PET perfusion tracer, yielded discrepant results. We reevaluated (82)Rb dosimetry using human in vivo biokinetic measurements. Ten healthy volunteers underwent dynamic PET/CT (6 contiguous table positions, each with separate (82)Rb infusion). Source organ volumes of interest were delineated on the CT images and transferred to the PET images to obtain time-integrated activity coefficients. Radiation doses were estimated using OLINDA/EXM 1.0. The highest mean absorbed organ doses (μGy/MBq) were observed for the kidneys (5.81), heart wall (3.86), and lungs (2.96). Mean effective doses were 1.11 ± 0.22 and 1.26 ± 0.20 μSv/MBq using the tissue-weighting factors of the International Commission on Radiological Protection (ICRP), publications 60 and 103, respectively. Our current (82)Rb dosimetry suggests reasonably low radiation exposure. On the basis of this study, a clinical (82)Rb injection of 2 × 1,480 MBq (80 mCi) would result in a mean effective dose of 3.7 mSv using the weighting factors of the ICRP 103-only slightly above the average annual natural background exposure in the United States (3.1 mSv).

Advanced Exposure Metrics For Chemical Risk Analysis: Systems Biology and 'Omic-based Biomarkers for Exposure Reconstruction

EPA Science Inventory

Direct measurement of human exposure to environmental contaminants in real time (when the exposure is actually occurring) is rare and difficult to obtain. This frustrates both exposure assessments and investigations into the linkage between chemical exposure and human disease. ...

FACTORS EFFECTING EXPOSURES TO VOCS DURING COMMUTING IN CALIFORNIA

EPA Science Inventory

On the average, Californian's spend between one and three hours each day commuting. The contribution from in-vehicle exposures to air toxics may be a significant component of total air exposure. Although pollutant concentration data are important for exposure assessments, onl...

Human exposure to polybrominated diphenyl ethers (PBDE), as evidenced by data from a duplicate diet study, indoor air, house dust, and biomonitoring in Germany.

PubMed

Fromme, Hermann; Körner, Wolfgang; Shahin, Nabil; Wanner, Antonia; Albrecht, Michael; Boehmer, Sigrun; Parlar, Harun; Mayer, Richard; Liebl, Bernhard; Bolte, Gabriele

2009-11-01

Polybrominated diphenyl ethers (PBDE) are used as flame retardants in a wide variety of products. As part of the Integrated Exposure Assessment Survey (INES), this study aimed to characterize the exposure of an adult German population using duplicate diet samples, which were collected daily over seven consecutive days, and indoor air and house dust measurements. Our study population consisted of 27 female and 23 male healthy subjects, aged 14-60 years, all of whom resided in 34 homes in southern Bavaria. In these 34 residences the air was sampled using glass fiber filters and polyurethane foams and the dust was collected from used vacuum cleaner bags. The median (95th percentile) daily dietary intake of six Tetra- to HeptaBDE congeners was 1.2 ng/kg b.w. (3.3 ng/kg b.w.) or 67.8 ng/day (208 ng/day) (calculated from the 7-day median values of each study subject). Concentrations in indoor air and dust (cumulative Tri- to DecaBDE congener readings) ranged from 8.2 to 477 pg/m(3) (median: 37.8 pg/m(3)) and 36.6 to 1580 ng/g (median: 386 ng/g), respectively. For some congeners, we identified a significant correlation between air and dust levels. The median (95th percentile) blood concentration of total Tetra- to HexaBDE congener readings was 5.6 (13.2)ng/g lipid. No significant sex differences were observed, but higher blood concentrations were found in younger participants. Using a simplified toxicokinetic model to predict the body burden from exposure doses led to results that were of the same order of magnitude as the measured blood concentrations. Based on these measurements and given our exposure assumptions, we estimated for the total tetra- to heptabrominated congener count an average (high) comprehensive total daily intake of 1.2 ng/kg b.w. (2.5 ng/kg b.w.). Overall, our results suggest that dietary exposure is the dominant intake pathway at least in our study population, responsible for 97% (average intake) and 95% (high intake) of the total intake of an adult population.

Comparison of human exposure model estimates of PM2.5 exposure variability using fine-scale CMAQ simulations from the Baltimore DISCOVER-AQ evaluation

EPA Science Inventory

Human exposure models estimate population distributions of exposure to air pollutants by combining ambient (outdoor) concentration data with human activity patterns to account for the time people spend in different locations (e.g., outdoors, indoors, in vehicles) and the various ...

Temporal Profile of Gene Expression Alterations in Primary Human Bronchial Epithelial Cells Following In Vivo Exposure to Ozone

EPA Science Inventory

RATIONALE: Ozone (Os) isa ubiquitous air pollutant that has been shown to have a detrimental effect on human health. Controlled exposure studies in humans have demonstrated that acute exposure to 03 results in reversible reduction in lung function immediately post-exposure, incre...

MANAGEMENT AND DISSEMINATION OF HUMAN EXPOSURE DATABASES AND OTHER DATABASES NEEDED FOR HUMAN EXPOSURE MODELING AND ANALYSIS

EPA Science Inventory

Researchers in the National Exposure Research Laboratory (NERL) have performed a number of large human exposure measurement studies during the past decade. It is the goal of the NERL to make the data available to other researchers for analysis in order to further the scientific ...

Human exposure in low Earth orbit

NASA Technical Reports Server (NTRS)

Wilson, J. W.; Cucinotta, F.

1984-01-01

Human exposure to trapped electrons and protons in low Earth orbit (LEO) is evaluated on a basis of a simple approximation of the human geometry for spherical shell shields of varying thickness. A data base is presented that may be used to make preliminary assessment of the impact of radiation exposure constraints on human performance. Detailed shielding studies should be performed before final design considerations. A sample impact assessment is discussed on the basis of presently accepted allowable exposure limits. A brief discussion is given on the anticipated impact of an ongoing reassessment of allowable exposure limits.

Analysis of proto-oncogene and heat-shock protein gene expression in human derived cell-lines exposed in vitro to an intermittent 1.9 GHz pulse-modulated radiofrequency field.

PubMed

Chauhan, Vinita; Mariampillai, Anusiyanthan; Gajda, Greg B; Thansandote, Artnarong; McNamee, James P

2006-05-01

Several studies have reported that radiofrequency (RF) fields, as emitted by mobile phones, may cause changes in gene expression in cultured human cell-lines. The current study was undertaken to evaluate this possibility in two human-derived immune cell-lines. HL-60 and Mono-Mac-6 (MM6) cells were individually exposed to intermittent (5 min on, 10 min off) 1.9 GHz pulse-modulated RF fields at a average specific absorption rate (SAR) of 1 and 10 W/kg at 37 +/- 0.5 degrees C for 6 h. Concurrent negative and positive (heat-shock for 1 h at 43 degrees C) controls were conducted with each experiment. Immediately following RF field exposure (T = 6 h) and 18 h post-exposure (T = 24 h), cell pellets were collected from each of the culture dishes and analyzed for transcript levels of proto-oncogenes (c-jun, c-myc and c-fos) and the stress-related genes (heat shock proteins (HSP) HSP27 and HSP70B) by quantitative reverse transcriptase polymerase chain reaction (RT-PCR). No significant effects were observed in mRNA expression of HSP27, HSP70, c-jun, c-myc or c-fos between the sham and RF-exposed groups, in either of the two cell-lines. However, the positive (heat-shock) control group displayed a significant elevation in the expression of HSP27, HSP70, c-fos and c-jun in both cell-lines at T = 6 and 24 h, relative to the sham and negative control groups. This study found no evidence that exposure of cells to non-thermalizing levels of 1.9 GHz pulse-modulated RF fields can cause any detectable change in stress-related gene expression.

Human Exposure Modeling - Databases to Support Exposure Modeling

EPA Pesticide Factsheets

Human exposure modeling relates pollutant concentrations in the larger environmental media to pollutant concentrations in the immediate exposure media. The models described here are available on other EPA websites.

Cooking and co-ingested polyphenols reduce in vitro methylmercury bioaccessibility from fish and may alter exposure in humans.

PubMed

Girard, Catherine; Charette, Tania; Leclerc, Maxime; Shapiro, B Jesse; Amyot, Marc

2018-03-01

Fish consumption is a major pathway for mercury exposure in humans. Current guidelines and risk assessments assume that 100% of methylmercury (MeHg) in fish is absorbed by the human body after ingestion. However, a growing body of literature suggests that this absorption rate may be overestimated. We used an in vitro digestion method to measure MeHg bioaccessibility in commercially-purchased fish, and investigated the effects of dietary practices on MeHg bioaccessibility. Cooking had the greatest effect, decreasing bioaccessibility on average to 12.5±5.6%. Polyphenol-rich beverages also significantly reduced bioaccessibility to 22.7±3.8% and 28.6±13.9%, for green and black tea respectively. We confirmed the suspected role of polyphenols in tea as being a driver of MeHg's reduced bioaccessibility, and found that epicatechin, epigallocatechin gallate, rutin and cafeic acid could individually decrease MeHg bioaccessibility by up to 55%. When both cooking and polyphenol-rich beverage treatments were combined, only 1% of MeHg remained bioaccessible. These results call for in vivo validation, and suggest that dietary practices should be considered when setting consumer guidelines for MeHg. More realistic risk assessments could promote consumption of fish as a source of fatty acids, which can play a protective role against cardiovascular disease. Copyright © 2017 Elsevier B.V. All rights reserved.

Fluoride concentration level in rural area in Poldasht city and daily fluoride intake based on drinking water consumption with temperature.

PubMed

Mohammadi, Ali Akbar; Yousefi, Mahmood; Mahvi, Amir Hossein

2017-08-01

Long-term exposure to high level of fluoride can caused several adverse effects on human health including dental and skeletal fluorosis. We investigated all the drinking water source located in rural areas of Poldasht city, west Azerbaijan Province, North West Iran between 2014 and 2015. Fluoride concentration of water samples was measured by SPADNS method. We found that in the villages of Poldasht the average of fluoride concentration in drinking water sources (well, and the river) was in the range mg/l 0.28-10.23. The average daily received per 2 l of drinking water is in the range mg/l 0.7-16.6 per day per person. Drinking water demands cause fluorosis in the villages around the area residents and based on the findings of this study writers are announced suggestions below in order to take care of the health of area residents.

Impact of Orientation on the Vitamin D Weighted Exposure of a Human in an Urban Environment

PubMed Central

Schrempf, Michael; Thuns, Nadine; Lange, Kezia

2017-01-01

The vitamin D3-weighted UV exposure of a human with vertical posture was calculated for urban locations to investigate the impact of orientation and obstructions on the exposure. Human exposure was calculated by using the 3D geometry of a human and integrating the radiance, i.e., the radiant energy from the direct solar beam and the diffuse sky radiation from different incident and azimuth angles. Obstructions of the sky are derived from hemispherical images, which are recorded by a digital camera with a fisheye lens. Due to the low reflectivity of most surfaces in the UV range, the radiance from obstructed sky regions was neglected. For spring equinox (21 March), the exposure of a human model with winter clothing in an environment where obstructions cover 40% of the sky varies by up to 25%, depending on the orientation of the human model to the sun. The calculation of the accumulated vitamin D3-weighted exposure of a human with winter clothing walking during lunch break shows that human exposure is reduced by the obstruction of buildings and vegetation by 40%. PMID:28813022

Assessment of the effect of population and diary sampling methods on estimation of school-age children exposure to fine particles.

PubMed

Che, W W; Frey, H Christopher; Lau, Alexis K H

2014-12-01

Population and diary sampling methods are employed in exposure models to sample simulated individuals and their daily activity on each simulation day. Different sampling methods may lead to variations in estimated human exposure. In this study, two population sampling methods (stratified-random and random-random) and three diary sampling methods (random resampling, diversity and autocorrelation, and Markov-chain cluster [MCC]) are evaluated. Their impacts on estimated children's exposure to ambient fine particulate matter (PM2.5 ) are quantified via case studies for children in Wake County, NC for July 2002. The estimated mean daily average exposure is 12.9 μg/m(3) for simulated children using the stratified population sampling method, and 12.2 μg/m(3) using the random sampling method. These minor differences are caused by the random sampling among ages within census tracts. Among the three diary sampling methods, there are differences in the estimated number of individuals with multiple days of exposures exceeding a benchmark of concern of 25 μg/m(3) due to differences in how multiday longitudinal diaries are estimated. The MCC method is relatively more conservative. In case studies evaluated here, the MCC method led to 10% higher estimation of the number of individuals with repeated exposures exceeding the benchmark. The comparisons help to identify and contrast the capabilities of each method and to offer insight regarding implications of method choice. Exposure simulation results are robust to the two population sampling methods evaluated, and are sensitive to the choice of method for simulating longitudinal diaries, particularly when analyzing results for specific microenvironments or for exposures exceeding a benchmark of concern. © 2014 Society for Risk Analysis.

The Cumulative Lifting Index (CULI) for the Revised NIOSH Lifting Equation: Quantifying Risk for Workers With Job Rotation.

PubMed

Garg, Arun; Kapellusch, Jay M

2016-08-01

The objectives were to: (a) develop a continuous frequency multiplier (FM) for the Revised NIOSH Lifting Equation (RNLE) as a function of lifting frequency and duration of a lifting task, and (b) describe the Cumulative Lifting Index (CULI), a methodology for estimating physical exposure to workers with job rotation. The existing FM for the RNLE (FME) does not differentiate between task duration >2 hr and <8 hr, which makes quantifying physical exposure to workers with job rotation difficult and presents challenges to job designers. Using the existing FMs for 1, 2, and 8 hr of task durations, we developed a continuous FM (FMP) that extends to 12 hr per day. We simulated 157,500 jobs consisting of two tasks each and, using different combinations of Frequency Independent Lifting Index, lifting frequency and duration of lifting. Biomechanical stresses were estimated using the CULI, time-weighted average (TWA), and peak exposure. The median difference between FME and FMP was ±1% (range: 0%-15%). Compared to CULI, TWA underestimated risk of low-back pain (LBP) for 18% to 30% of jobs, and peak exposure for an assumed 8-hr work shift overestimated risk of LBP for 20% to 25% of jobs. Peak task exposure showed 90% agreement with CULI but ignored one of two tasks. The CULI partially addressed the underestimation of physical exposure using the TWA approach and overestimation of exposure using the peak-exposure approach. The proposed FM and CULI may provide more accurate physical exposure estimates, and therefore estimated risk of LBP, for workers with job rotation. © 2016, Human Factors and Ergonomics Society.

Atrazine and nitrate in drinking water and the risk of preterm delivery and low birth weight in four Midwestern states.

PubMed

Stayner, Leslie Thomas; Almberg, Kirsten; Jones, Rachael; Graber, Judith; Pedersen, Marie; Turyk, Mary

2017-01-01

Atrazine and nitrate are common contaminants in water, and there is limited evidence that they are associated with adverse birth outcomes. The objective of this study was to examine whether atrazine and nitrate in water are associated with an increased risk of preterm delivery (PTD) and term low birth weight (LBW). The study included a total of 134,258 singletons births born between January 1, 2004 and December 31, 2008 from 46 counties in four Midwestern states with public water systems that were included in the U.S. Environmental Protection Agency (EPA)'s atrazine monitoring program (AMP). Counties with a population of >300,000 were eliminated from the analyses in order to avoid confounding by urbanicity. Monthly child's sex, race and Hispanic ethnicity specific data were obtained from the states for estimating rates of PTD (<37 weeks) and very preterm (VPTD, <32 weeks), term LBW (<2.5kg among infants born at term) and very low birth weight (VLBW, <1.5kg). The rates were linked with county specific monthly estimates of the concentration of atrazine and nitrate in finished water. Multivariable negative binomial models were fitted to examine the association between the exposures and the adverse birth outcomes. Models were fitted with varying restrictions on the percentage of private well usage in the counties in order to limit the degree of exposure misclassification. Estimated water concentrations of atrazine (mean=0.42 ppb) and nitrate (mean=0.95ppm) were generally low. Neither contaminant was associated with an increased risk of term LBW. Atrazine exposure was associated with a significant increased rate of PTD when well use was restricted to 10% and the exposure was averaged over 4-6 months prior to birth (Rate Ratio for 1ppm increase [RR 1ppm ]=1.08, 95%CI=1.05,1.11) or over 9 months prior to birth (RR 1ppm =1.10, 95%CI=1.01,1.20). Atrazine exposure was also associated with an increased rate of VPTD when when well use was restricted to 10% and the exposure was averaged over 7-9 months prior to birth (RR 1ppm =1.19, 95%CI=1.04,1.36). Exposure to nitrate was significantly associated with an increased rate of VPTD (RR 1ppm =1.08, 95%CI=1.02,1.15) and VLBW (RR 1ppm =1.17, 95%CI=1.08,1.25) when well use was restricted to 20% and the exposure was averaged over 9 months prior to birth. The positive and negative findings from our study need to be interpreted cautiously given its ecologic design, and limitations in the data for the exposures and other risk factors. Nonetheless, our findings do raise concerns about the potential adverse effects of these common water contaminants on human development and health, and the adequacy of current regulatory standards. Further studies of these issues are needed with individual level outcome data and more refined estimates of exposure. Copyright © 2016 Elsevier Inc. All rights reserved.

American association of poison control centers database characterization of human tilmicosin exposures, 2001-2005.

PubMed

Oakes, Jennifer; Seifert, Steven

2008-12-01

Tilmicosin is a veterinary antibiotic with significant human toxicity at doses commonly used in animals, but the parenteral dose-response relationship has not been well characterized. Human exposures to tilmicosin in the database of the American Association of Poison Control Centers (AAPCC) from 2001 to 2005 were analyzed for demographic associations, exposure dose, clinical effects and outcomes. Over the 5-year period, there were 1,291 single-substance human exposures to tilmicosin. The mean age was 39.1 years, and 80% were male. By route there were 768 (54%) parenteral exposures. Patients with parenteral exposures had a significantly increased likelihood of being seen at a healthcare facility, admission, and admission to an ICU. With nonparenteral exposure, most had no clinical effects or minor effects, and there were no major effects or deaths. With parenteral exposure, moderate effects occurred in 46 (6%), major effects in 2 (0.3%) and there were 4 (0.5%) deaths, two of which were suicides. A dose-response relationship could be demonstrated. Clinical effect durations of up to a week occurred at even the lowest dose range. Over 250 cases of human tilmicosin exposure are reported to poison centers per year and over 150 of those are parenteral. Most exposures produce no or minor effects, but fatalities have occurred with parenteral exposure. The case fatality rate in parenteral exposures is 10 times the case fatality rate for all human exposures in the AAPCC database. Significant adverse and prolonged effects are reported at parenteral doses > 0.5 mL, suggesting that all parenteral exposures should be referred for healthcare facility evaluation.

PM ACTIVITY PATTERN RESEARCH

EPA Science Inventory

Human activity/uptake rate data are necessary to estimate potential human exposure and intake dose to environmental pollutants and to refine human exposure models. Personal exposure monitoring studies have demonstrated the critical role that activities play in explaining and pre...

Inhalation Exposures to Particulate Matter and Carbon Monoxide during Ethiopian Coffee Ceremonies in Addis Ababa: A Pilot Study

PubMed Central

Keil, Chris; Kassa, Hailu; Brown, Alexander; Kumie, Abera; Tefera, Worku

2010-01-01

The unique Ethiopian cultural tradition of the coffee ceremony increases inhalation exposures to combustion byproducts. This pilot study evaluated exposures to particulate matter and carbon monoxide in ten Addis Ababa homes during coffee ceremonies. For coffee preparers the geometric mean (57 μg/m3) and median (72 μg/m3) contributions to an increase in a 24-hour time-weighted average exposure were above World Health Organization (WHO) guidelines. At 40% of the study sites the contribution to the 24-hour average exposure was greater than twice the WHO guideline. Similar exposure increases existed for ceremony participants. Particulate matter concentrations may be related to the use of incense during the ceremony. In nearly all homes the WHO guideline for a 60-minute exposure to carbon monoxide was exceeded. Finding control measures to reduce these exposures will be challenging due to the deeply engrained nature of this cultural practice and the lack of availability of alternative fuels. PMID:20886061

Inhalation exposures to particulate matter and carbon monoxide during Ethiopian coffee ceremonies in Addis Ababa: a pilot study.

PubMed

Keil, Chris; Kassa, Hailu; Brown, Alexander; Kumie, Abera; Tefera, Worku

2010-01-01

The unique Ethiopian cultural tradition of the coffee ceremony increases inhalation exposures to combustion byproducts. This pilot study evaluated exposures to particulate matter and carbon monoxide in ten Addis Ababa homes during coffee ceremonies. For coffee preparers the geometric mean (57 μg/m³) and median (72 μg/m³) contributions to an increase in a 24-hour time-weighted average exposure were above World Health Organization (WHO) guidelines. At 40% of the study sites the contribution to the 24-hour average exposure was greater than twice the WHO guideline. Similar exposure increases existed for ceremony participants. Particulate matter concentrations may be related to the use of incense during the ceremony. In nearly all homes the WHO guideline for a 60-minute exposure to carbon monoxide was exceeded. Finding control measures to reduce these exposures will be challenging due to the deeply engrained nature of this cultural practice and the lack of availability of alternative fuels.

The margin of internal exposure (MOIE) concept for dermal risk assessment based on oral toxicity data - A case study with caffeine.

PubMed

Bessems, Jos G M; Paini, Alicia; Gajewska, Monika; Worth, Andrew

2017-12-01

Route-to-route extrapolation is a common part of human risk assessment. Data from oral animal toxicity studies are commonly used to assess the safety of various but specific human dermal exposure scenarios. Using theoretical examples of various user scenarios, it was concluded that delineation of a generally applicable human dermal limit value is not a practicable approach, due to the wide variety of possible human exposure scenarios, including its consequences for internal exposure. This paper uses physiologically based kinetic (PBK) modelling approaches to predict animal as well as human internal exposure dose metrics and for the first time, introduces the concept of Margin of Internal Exposure (MOIE) based on these internal dose metrics. Caffeine was chosen to illustrate this approach. It is a substance that is often found in cosmetics and for which oral repeated dose toxicity data were available. A rat PBK model was constructed in order to convert the oral NOAEL to rat internal exposure dose metrics, i.e. the area under the curve (AUC) and the maximum concentration (C max ), both in plasma. A human oral PBK model was constructed and calibrated using human volunteer data and adapted to accommodate dermal absorption following human dermal exposure. Use of the MOIE approach based on internal dose metrics predictions provides excellent opportunities to investigate the consequences of variations in human dermal exposure scenarios. It can accommodate within-day variation in plasma concentrations and is scientifically more robust than assuming just an exposure in mg/kg bw/day. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

High Incidence of Human Rabies Exposure in Northwestern Tigray, Ethiopia: A Four-Year Retrospective Study

PubMed Central

Teklu, Gebreyohans Gebru; Hailu, Teweldemedhn Gebretinsae; Eshetu, Gebremedhin Romha

2017-01-01

Background Rabies is a fatal zoonotic disease that has been known in Ethiopia for centuries in society as “Mad Dog Disease”. It is an important disease with veterinary and public health significance in the North western zone of Tigray where previous studies have not been conducted. Frequent occurrence of outbreaks in the area led the researchers to carry out a four year retrospective study to estimate the incidence of human rabies exposure in Northwestern Tigray, Ethiopia. Methodology A referent study was conducted on human rabies exposure cases recorded from 2012 to 2015 at Suhul hospital, Shire Endaselase, Northwestern Tigray, Ethiopia. Exposure cases included in this research constituted victims bitten by unprovoked dogs and who received post exposure prophylaxis (PEP) at the hospital. Two thousand one hundred eighty human rabies exposure cases retrieved from the rabies case database were included in this study. Principal findings The majority of the exposed cases were males (1363/2180, 63%). Age wise, the most exposed age group was ≥15 years in all the study years: 166 (58%), 335 (65%), 492 (66%) and 394 (63%) in 2012, 2013, 2014 and 2015, respectively. Similarly, exposure cases for human rabies increased with age in both males and females across the study years. The incidence of human rabies exposure cases calculated per 100,000 populations was 35.8, 63.0, 89.8 and 73.1 in 2012, 2013, 2014 and 2015, respectively. Binary logistic regression analysis revealed that being male was a risk for human rabies exposure in all the study years. Conclusion The study discovered the highest annual human rabies exposure incidence in Ethiopia. This suggests an urgent need for synergistic efforts of human and animal health sectors to implement prevention and control strategies in this area. PMID:28060935

Identifying populations sensitive to environmental chemicals by simulating toxicokinetic variability.

PubMed

Ring, Caroline L; Pearce, Robert G; Setzer, R Woodrow; Wetmore, Barbara A; Wambaugh, John F

2017-09-01

The thousands of chemicals present in the environment (USGAO, 2013) must be triaged to identify priority chemicals for human health risk research. Most chemicals have little of the toxicokinetic (TK) data that are necessary for relating exposures to tissue concentrations that are believed to be toxic. Ongoing efforts have collected limited, in vitro TK data for a few hundred chemicals. These data have been combined with biomonitoring data to estimate an approximate margin between potential hazard and exposure. The most "at risk" 95th percentile of adults have been identified from simulated populations that are generated either using standard "average" adult human parameters or very specific cohorts such as Northern Europeans. To better reflect the modern U.S. population, we developed a population simulation using physiologies based on distributions of demographic and anthropometric quantities from the most recent U.S. Centers for Disease Control and Prevention National Health and Nutrition Examination Survey (NHANES) data. This allowed incorporation of inter-individual variability, including variability across relevant demographic subgroups. Variability was analyzed with a Monte Carlo approach that accounted for the correlation structure in physiological parameters. To identify portions of the U.S. population that are more at risk for specific chemicals, physiologic variability was incorporated within an open-source high-throughput (HT) TK modeling framework. We prioritized 50 chemicals based on estimates of both potential hazard and exposure. Potential hazard was estimated from in vitro HT screening assays (i.e., the Tox21 and ToxCast programs). Bioactive in vitro concentrations were extrapolated to doses that produce equivalent concentrations in body tissues using a reverse dosimetry approach in which generic TK models are parameterized with: 1) chemical-specific parameters derived from in vitro measurements and predicted from chemical structure; and 2) with physiological parameters for a virtual population. For risk-based prioritization of chemicals, predicted bioactive equivalent doses were compared to demographic-specific inferences of exposure rates that were based on NHANES urinary analyte biomonitoring data. The inclusion of NHANES-derived inter-individual variability decreased predicted bioactive equivalent doses by 12% on average for the total population when compared to previous methods. However, for some combinations of chemical and demographic groups the margin was reduced by as much as three quarters. This TK modeling framework allows targeted risk prioritization of chemicals for demographic groups of interest, including potentially sensitive life stages and subpopulations. Published by Elsevier Ltd.

A Multi-Band Body-Worn Distributed Radio-Frequency Exposure Meter: Design, On-Body Calibration and Study of Body Morphology

PubMed Central

Thielens, Arno; Agneessens, Sam; Van Torre, Patrick; Van den Bossche, Matthias; Eeftens, Marloes; Huss, Anke; Vermeulen, Roel; de Seze, René; Mazet, Paul; Cardis, Elisabeth; Röösli, Martin; Martens, Luc; Joseph, Wout

2018-01-01

A multi-band Body-Worn Distributed exposure Meter (BWDM) calibrated for simultaneous measurement of the incident power density in 11 telecommunication frequency bands, is proposed. The BDWM consists of 22 textile antennas integrated in a garment and is calibrated on six human subjects in an anechoic chamber to assess its measurement uncertainty in terms of 68% confidence interval of the on-body antenna aperture. It is shown that by using multiple antennas in each frequency band, the uncertainty of the BWDM is 22 dB improved with respect to single nodes on the front and back of the torso and variations are decreased to maximum 8.8 dB. Moreover, deploying single antennas for different body morphologies results in a variation up to 9.3 dB, which is reduced to 3.6 dB using multiple antennas for six subjects with various body mass index values. The designed BWDM, has an improved uncertainty of up to 9.6 dB in comparison to commercially available personal exposure meters calibrated on body. As an application, an average incident power density in the range of 26.7–90.8 μW·m−2 is measured in Ghent, Belgium. The measurements show that commercial personal exposure meters underestimate the actual exposure by a factor of up to 20.6. PMID:29346280

Personal carbon monoxide exposure in Helsinki, Finland

NASA Astrophysics Data System (ADS)

Scotto di Marco, Greta; Kephalopoulos, Stylianos; Ruuskanen, Juhani; Jantunen, Matti

Personal exposure concentrations of carbon monoxide (CO) were measured for the adult urban population of Helsinki, Finland, as part of the multi-centre European EXPOLIS study. The arithmetic mean of the 48 h average personal CO exposure concentration was 1.3 mg m -3 for participants not exposed to environmental tobacco smoke (ETS) and 1.6 mg m -3 for those exposed to ETS at any time and in any microenvironment. The maximum 8 and 1 h exposure values were 2.0 and 2.6 mg m -3, and 4.3 and 5.7 mg m -3, respectively. As tobacco smoke is one of the major sources of CO, therefore the personal mean exposures of ETS participants were higher than the non-ETS participants for all averaging times. The long- and short-term personal exposures were higher in winter than in summer for all participants. In order to analyse in more detail the correlation between the time-activity patterns and exposure levels, cluster analysis was performed using 24 h personal exposure profiles of 1 h moving averages. The results showed clearly that the major source of CO for non-ETS exposed participants are traffic emissions. The majority of the diurnal exposure profiles showed two notable exposure peaks corresponding to the morning and evening traffic rush hours. The time spent in street traffic was the most relevant factor for describing the short-term personal exposures. The more time was spent commuting by car the higher were the exposures. The long-term exposure levels were linked both to the time spent commuting and home location. People living in low-traffic suburban areas and working in downtown spent more time commuting and ended up experiencing similar long-term exposure levels than people who lived in heavy-traffic downtown areas, but spent little time commuting. For ETS exposed participants the personal exposure profiles were dominated by both tobacco smoke and traffic emissions.

Mobile phone signal exposure triggers a hormesis-like effect in Atm+/+ and Atm-/- mouse embryonic fibroblasts.

PubMed

Sun, Chuan; Wei, Xiaoxia; Fei, Yue; Su, Liling; Zhao, Xinyuan; Chen, Guangdi; Xu, Zhengping

2016-11-18

Radiofrequency electromagnetic fields (RF-EMFs) have been classified by the International Agency for Research on Cancer as possible carcinogens to humans; however, this conclusion is based on limited epidemiological findings and lacks solid support from experimental studies. In particular, there are no consistent data regarding the genotoxicity of RF-EMFs. Ataxia telangiectasia mutated (ATM) is recognised as a chief guardian of genomic stability. To address the debate on whether RF-EMFs are genotoxic, we compared the effects of 1,800 MHz RF-EMF exposure on genomic DNA in mouse embryonic fibroblasts (MEFs) with proficient (Atm +/+ ) or deficient (Atm -/- ) ATM. In Atm +/+ MEFs, RF-EMF exposure for 1 h at an average special absorption rate of 4.0 W/kg induced significant DNA single-strand breaks (SSBs) and activated the SSB repair mechanism. This effect reduced the DNA damage to less than that of the background level after 36 hours of exposure. In the Atm -/- MEFs, the same RF-EMF exposure for 12 h induced both SSBs and double-strand breaks and activated the two repair processes, which also reduced the DNA damage to less than the control level after prolonged exposure. The observed phenomenon is similar to the hormesis of a toxic substance at a low dose. To the best of our knowledge, this study is the first to report a hormesis-like effect of an RF-EMF.

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

PubMed Central

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

2012-01-01

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

Human occupational and nonoccupational exposure to fibers.

PubMed Central

Esmen, N A; Erdal, S

1990-01-01

Human exposure to fibers in occupational and nonoccupational environments has been a health concern for nearly a century. In this review, selected results from the literature are presented to highlight the availability, limitations, and interpretive difficulties associated with the past and current human fiber exposure data sets. In the traditionally defined asbestos fibers, large amounts of the data available suffer from the diversity of sample collection and analysis methods. Two simple generalizations suggest that occupational exposures are several orders of magnitude higher than that of environmental exposures; and currently extant data and the current routine measurement practices present significant difficulties in the consistent interpretation of the data with respect to health effects. The data on the human exposures to man-made vitreous fibers are much more complete than the data on asbestos exposure, while exposure data on other man-made fibrous materials are lacking. The human exposure data to many minerals which, at times, exist in fibrous habit, are very scanty, and in view of the biological activity of some of these fibers, this lack may be of significant concern. PMID:2272324

New head equivalent phantom for task and image performance evaluation representative for neurovascular procedures occurring in the Circle of Willis

NASA Astrophysics Data System (ADS)

Ionita, Ciprian N.; Loughran, Brendan; Jain, Amit; Swetadri Vasan, S. N.; Bednarek, Daniel R.; Levy, Elad; Siddiqui, Adnan H.; Snyder, Kenneth V.; Hopkins, L. N.; Rudin, Stephen

2012-03-01

Phantom equivalents of different human anatomical parts are routinely used for imaging system evaluation or dose calculations. The various recommendations on the generic phantom structure given by organizations such as the AAPM, are not always accurate when evaluating a very specific task. When we compared the AAPM head phantom containing 3 mm of aluminum to actual neuro-endovascular image guided interventions (neuro-EIGI) occurring in the Circle of Willis, we found that the system automatic exposure rate control (AERC) significantly underestimated the x-ray parameter selection. To build a more accurate phantom for neuro-EIGI, we reevaluated the amount of aluminum which must be included in the phantom. Human skulls were imaged at different angles, using various angiographic exposures, at kV's relevant to neuro-angiography. An aluminum step wedge was also imaged under identical conditions, and a correlation between the gray values of the imaged skulls and those of the aluminum step thicknesses was established. The average equivalent aluminum thickness for the skull samples for frontal projections in the Circle of Willis region was found to be about 13 mm. The results showed no significant changes in the average equivalent aluminum thickness with kV or mAs variation. When a uniform phantom using 13 mm aluminum and 15 cm acrylic was compared with an anthropomorphic head phantom the x-ray parameters selected by the AERC system were practically identical. These new findings indicate that for this specific task, the amount of aluminum included in the head equivalent must be increased substantially from 3 mm to a value of 13 mm.

Distinct Immunomodulation of Bone Marrow-Derived Dendritic Cell Responses to Lactobacillus plantarum WCFS1 by Two Different Polysaccharides Isolated from Lactobacillus rhamnosus LOCK 0900

PubMed Central

Jachymek, Wojciech; Srutkova, Dagmar; Brzozowska, Ewa; Kozakova, Hana; Gamian, Andrzej

2014-01-01

The structures of polysaccharides (PS) isolated from Lactobacillus rhamnosus LOCK 0900 and results from stimulation of mouse bone marrow-derived dendritic cells (BM-DC) and human embryonal kidney (HEK293) cells stably transfected with Toll-like receptors (TLR) upon exposure to these antigens were studied. L. rhamnosus LOCK 0900 produces PS that differ greatly in their structure. The polymer L900/2, with a high average molecular mass of 830 kDa, is a branched heteropolysaccharide with a unique repeating unit consisting of seven sugar residues and pyruvic acid, whereas L900/3 has a low average molecular mass of 18 kDa and contains a pentasaccharide repeating unit and phosphorus. Furthermore, we found that both described PS neither induce cytokine production and maturation of mouse BM-DC nor induce signaling through TLR2/TLR4 receptors. However, they differ profoundly in their abilities to modulate the BM-DC immune response to the well-characterized human isolate Lactobacillus plantarum WCFS1. Exposure to L900/2 enhanced interleukin-10 (IL-10) production induced by L. plantarum WCFS1, while in contrast, L900/3 enhanced the production of IL-12p70. We conclude that PS, probably due to their chemical features, are able to modulate the immune responses to third-party antigens. The ability to induce regulatory IL-10 by L900/2 opens up the possibility to use this PS in therapy of inflammatory conditions, such as inflammatory bowel disease, whereas L900/3 might be useful in reverting the antigen-dependent Th2-skewed immune responses in allergies. PMID:25107979

Consistent, high-level ethanol consumption in pig-tailed macaques via a multiple-session, limited-intake, oral self-dosing procedure.

PubMed

Weed, Michael R; Wilcox, Kristin M; Ator, Nancy A; Hienz, Robert D

2008-06-01

Alcohol abuse is a major public health burden that can lead to many adverse health effects such as impaired hepatic, gastrointestinal, central nervous system and immune system function. Preclinical animal models of alcohol abuse allow for experimental control over variables often difficult to control in human clinical studies (e.g., ethanol exposure before or during the study, history of other drug use, access to medical care, nutritional status, etc). Nonhuman primate models in particular provide increased genetic, anatomic and physiologic similarity to humans, relative to rodent models. A small percentage of macaques will spontaneously consume large quantities of ethanol; however, most nonhuman primate models of "voluntary" ethanol intake produce relatively low daily ethanol intake in the majority of monkeys. To facilitate study of chronic exposure to high levels of ethanol intake, a macaque model has been developed that induces consistent, daily high-level ethanol consumption. This multiple-session procedure employed 4 drinking sessions per day, with sessions occurring once every 6 hours. The group average alcohol consumption was 4.6 g/kg/d (SEM 0.4), roughly twice the group average consumption of previous reports. Ethanol drinking sessions produced group mean blood ethanol levels of 95 mg/dl after 60 minutes, and fine motor control was impaired up to 90 minutes after a drinking session. This model of multiple-session, limited access, oral ethanol self-dosing produced consistent, high-level ethanol consumption with each session qualifying as a "binge" drinking session using the definition of "binge" provided by the NIAAA (>80 mg/dl/session). This model of ethanol drinking in macaques will be of great utility in the study of immunological, physiological and behavioral effects of ethanol in nonhuman primates.

Cancer incidence attributable to air pollution in Alberta in 2012

PubMed Central

Poirier, Abbey E.; Grundy, Anne; Khandwala, Farah; Friedenreich, Christine M.; Brenner, Darren R.

2017-01-01

Background: The International Agency for Research on Cancer has classified outdoor air pollution (fine particulate matter [PM2.5]) as a Group 1 lung carcinogen in humans. We aimed to estimate the proportion of lung cancer cases attributable to PM2.5 exposure in Alberta in 2012. Methods: Annual average concentrations of PM2.5 in 2011 for 22 communities across Alberta were extracted from the Clean Air Strategic Alliance Data Warehouse and were population-weighted across the province. Using 7.5 µg/m3 and 3.18 µg/m3 as the annual average theoretical minimum risk concentrations of PM2.5, we estimated the proportion of the population above this cut-off to determine the population attributable risk of lung cancer due to PM2.5 exposure. Results: The mean population-weighted concentration of PM2.5 for Alberta in 2011 was 10.03 µg/m3. We estimated relative risks of 1.02 and 1.06 for theoretical minimum risk PM2.5 concentration thresholds of 7.5 µg/m3 and 3.18 µg/m3, respectively. About 1.87%-5.69% of incident lung cancer cases in Alberta were estimated to be attributable to PM2.5 exposure. Interpretation: Our estimate of attributable burden is low compared to that reported in studies in other areas of the world owing to the relatively low levels of PM2.5 recorded in Alberta. Reducing PM2.5 emissions in Alberta should continue to be a priority to help decrease the burden of lung cancer in the population. PMID:28659352

Stochastic Human Exposure and Dose Simulation Model for Pesticides

EPA Science Inventory

SHEDS-Pesticides (Stochastic Human Exposure and Dose Simulation Model for Pesticides) is a physically-based stochastic model developed to quantify exposure and dose of humans to multimedia, multipathway pollutants. Probabilistic inputs are combined in physical/mechanistic algorit...

Bioaccessibility, dietary exposure and human risk assessment of heavy metals from market vegetables in Hong Kong revealed with an in vitro gastrointestinal model.

PubMed

Hu, Junli; Wu, Fuyong; Wu, Shengchun; Cao, Zhihong; Lin, Xiangui; Wong, Ming Hung

2013-04-01

A systematic survey of heavy metal (HM) concentrations and bioaccessibilities in market vegetables in Hong Kong were carried out for assessing potential health risk to local inhabitants. The average concentrations of Cd, Pb, Cr, Ni, Cu, and Zn in nine major groups of fresh vegetable varied within 0.007-0.053, 0.05-0.17, 0.05-0.24, 0.26-1.1, 0.62-3.0, and 0.96-4.3 mg kg(-1), respectively, and their average bioaccessibilities varied within 21-96%, 20-68%, 24-62%, 29-64%, 30-77%, and 69-94%, respectively. The bioaccessible estimated daily intakes (BEDIs) of Cd, Pb, Cr, Ni, Cu, and Zn from vegetables were far below the tolerable limits. The total bioaccessible target hazard quotient (TBTHQ) of the six HMs was 0.18 and 0.64 for average and high consumers, respectively, with Cd and leafy vegetable being the major risk contributors. Risk assessment of HMs from foods should be modified by taking bioaccessibility into account. Copyright © 2012 Elsevier Ltd. All rights reserved.

Human exposure assessment resources on the World Wide Web.

PubMed

Schwela, Dieter; Hakkinen, Pertti J

2004-05-20

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

Safety assessment for hair-spray resins: risk assessment based on rodent inhalation studies.

PubMed

Carthew, Philip; Griffiths, Heather; Keech, Stephen; Hartop, Peter

2002-04-01

The methods involved in the safety assessment of resins used in hair-spray products have received little peer review, or debate in the published literature, despite their widespread use, in both hairdressing salons and the home. The safety assessment for these resins currently involves determining the type of lung pathology that can be caused in animal inhalation exposure studies, and establishing the no-observable-effect level (NOEL) for these pathologies. The likely human consumer exposure is determined by techniques that model the simulated exposure under "in use" conditions. From these values it is then possible to derive the likely safety factors for human exposure. An important part of this process would be to recognize the intrinsic differences between rodents and humans in terms of the respiratory doses that each species experiences during inhalation exposures, for the purpose of the safety assessment. Interspecies scaling factors become necessary when comparing the exposure doses experienced by rats, compared to humans, because of basic differences between species in lung clearance rates and the alveolar area in the lungs. The rodent inhalation data and modeled human exposure to Resin 6965, a resin polymer that is based on vinyl acetate, has been used to calculate the safety factor for human consumer exposure to this resin, under a range of "in use" exposure conditions. The use of this safety assessment process clearly demonstrates that Resin 6965 is acceptable for human consumer exposure under the conditions considered in this risk assessment.

Adapting Concepts from Systems Biology to Develop Systems Exposure Event Networks for Exposure Science Research

EPA Science Inventory

Systems exposure science has emerged from the traditional environmental exposure assessment framework and incorporates new concepts that link sources of human exposure to internal dose and metabolic processes. Because many human environmental studies are designed for retrospectiv...

Trends in Occupational Exposure to Styrene in the European Glass Fibre-Reinforced Plastics Industry

PubMed Central

Van Rooij, J. G. M.; Kasper, A.; Triebig, G.; Werner, P.; Kromhout, H.

2008-01-01

Aim: This study presents temporal trends of styrene exposure for workers in the European glass fibre-reinforced plastics (GRP) industry during the period 1966–2002. Methods: Data of personal styrene exposure measurements were retrieved from reports, databases and peer-reviewed papers. Only sources with descriptive statistics of personal measurements were accepted. The styrene exposure data cover personal air samples and biological monitoring data, that is, urinary styrene metabolites (mandelic acid and/or phenylglyoxylic acid) and styrene in blood. Means of series of measurements were categorized by year, country, production process, job and sampling strategy. Linear mixed models were used to identify temporal trends and factors affecting exposure levels. Results: Personal exposure measurements were available from 60 reports providing data on 24145 1–8-h time-weighted average shift personal air samples. Available data of biological exposure indicators included measurements of mandelic acid in post-shift urine (6361 urine samples being analysed). Trend analyses of the available styrene exposure data showed that the average styrene concentration in the breathing zone of open-mould workers in the European GRP industry has decreased on average by 5.3% per year during the period 1966–1990 and by only 0.4% annually in the period after 1990. The highest exposures were measured in Southern Europe and the lowest exposures in Northern Europe with Central Europe in between. Biological indicators of styrene (mandelic acid in post-shift urine) showed a somewhat steeper decline (8.9%), most likely because urine samples were collected in companies that showed a stronger decrease of styrene exposure in air than GRP companies where no biological measurements were carried out. PMID:18550625

Time-dependent effect of intensity of smoking and of occupational exposure to asbestos on the risk of lung cancer: results from the ICARE case-control study.

PubMed

Lévêque, Emilie; Lacourt, Aude; Luce, Danièle; Sylvestre, Marie-Pierre; Guénel, Pascal; Stücker, Isabelle; Leffondré, Karen

2018-05-18

To estimate the impact of intensity of both smoking and occupational exposure to asbestos on the risk of lung cancer throughout the whole exposure history. Data on 2026 male cases and 2610 male controls came from the French ICARE (Investigation of occupational and environmental causes of respiratory cancers) population-based, case-control study. Lifetime smoking history and occupational history were collected from standardised questionnaires and face-to-face interviews. Occupational exposure to asbestos was assessed using a job exposure matrix. The effects of annual average daily intensity of smoking (reported average number of cigarettes smoked per day) and asbestos exposure (estimated average daily air concentration of asbestos fibres at work) were estimated using a flexible weighted cumulative index of exposure in logistic regression models. Intensity of smoking in the 10 years preceding diagnosis had a much stronger association with the risk of lung cancer than more distant intensity. By contrast, intensity of asbestos exposure that occurred more than 40 years before diagnosis had a stronger association with the risk of lung cancer than more recent intensity, even if intensity in the 10 years preceding diagnosis also had a significant effect. Our results illustrate the dynamic of the effect of intensity of both smoking and occupational exposure to asbestos on the risk of lung cancer. They confirm that the timing of exposure plays an important role, and suggest that standard analytical methods assuming equal weights of intensity over the whole exposure history may be questionable. © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Guide to the evaluation of human exposure to noise from large wind turbines

NASA Technical Reports Server (NTRS)

Stephens, D. G.; Shepherd, K. P.; Hubbard, H. H.; Grosveld, F.

1982-01-01

Guidance for evaluating human exposure to wind turbine noise is provided and includes consideration of the source characteristics, the propagation to the receiver location, and the exposure of the receiver to the noise. The criteria for evaluation of human exposure are based on comparisons of the noise at the receiver location with the human perception thresholds for wind turbine noise and noise-induced building vibrations in the presence of background noise.

Long-Term PM2.5 Exposure and Respiratory, Cancer, and Cardiovascular Mortality in Older US Adults.

PubMed

Pun, Vivian C; Kazemiparkouhi, Fatemeh; Manjourides, Justin; Suh, Helen H

2017-10-15

The impact of chronic exposure to fine particulate matter (particulate matter with an aerodynamic diameter less than or equal to 2.5 μm (PM2.5)) on respiratory disease and lung cancer mortality is poorly understood. In a cohort of 18.9 million Medicare beneficiaries (4.2 million deaths) living across the conterminous United States between 2000 and 2008, we examined the association between chronic PM2.5 exposure and cause-specific mortality. We evaluated confounding through adjustment for neighborhood behavioral covariates and decomposition of PM2.5 into 2 spatiotemporal scales. We found significantly positive associations of 12-month moving average PM2.5 exposures (per 10-μg/m3 increase) with respiratory, chronic obstructive pulmonary disease, and pneumonia mortality, with risk ratios ranging from 1.10 to 1.24. We also found significant PM2.5-associated elevated risks for cardiovascular and lung cancer mortality. Risk ratios generally increased with longer moving averages; for example, an elevation in 60-month moving average PM2.5 exposures was linked to 1.33 times the lung cancer mortality risk (95% confidence interval: 1.24, 1.40), as compared with 1.13 (95% confidence interval: 1.11, 1.15) for 12-month moving average exposures. Observed associations were robust in multivariable models, although evidence of unmeasured confounding remained. In this large cohort of US elderly, we provide important new evidence that long-term PM2.5 exposure is significantly related to increased mortality from respiratory disease, lung cancer, and cardiovascular disease. © The Author(s) 2017. Published by Oxford University Press on behalf of the Johns Hopkins Bloomberg School of Public Health. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Auditory Exposure in the Neonatal Intensive Care Unit: Room Type and Other Predictors.

PubMed

Pineda, Roberta; Durant, Polly; Mathur, Amit; Inder, Terrie; Wallendorf, Michael; Schlaggar, Bradley L

2017-04-01

To quantify early auditory exposures in the neonatal intensive care unit (NICU) and evaluate how these are related to medical and environmental factors. We hypothesized that there would be less auditory exposure in the NICU private room, compared with the open ward. Preterm infants born at ≤ 28 weeks gestation (33 in the open ward, 25 in private rooms) had auditory exposure quantified at birth, 30 and 34 weeks postmenstrual age (PMA), and term equivalent age using the Language Environmental Acquisition device. Meaningful language (P < .0001), the number of adult words (P < .0001), and electronic noise (P < .0001) increased across PMA. Silence increased (P = .0007) and noise decreased (P < .0001) across PMA. There was more silence in the private room (P = .02) than the open ward, with an average of 1.9 hours more silence in a 16-hour period. There was an interaction between PMA and room type for distant words (P = .01) and average decibels (P = .04), indicating that changes in auditory exposure across PMA were different for infants in private rooms compared with infants in the open ward. Medical interventions were related to more noise in the environment, although parent presence (P = .009) and engagement (P  = .002) were related to greater language exposure. Average sound levels in the NICU were 58.9 ± 3.6 decibels, with an average peak level of 86.9 ± 1.4 decibels. Understanding the NICU auditory environment paves the way for interventions that reduce high levels of adverse sound and enhance positive forms of auditory exposure, such as language. Copyright © 2016 Elsevier Inc. All rights reserved.

Biomonitoring of polycyclic aromatic compounds in the urine of mining workers occupationally exposed to diesel exhaust.

PubMed

Seidel, Albrecht; Dahmann, Dirk; Krekeler, Horst; Jacob, Juergen

2002-02-01

Diesel exhaust is considered a probable human carcinogen by the IARC. Biomonitoring of workers occupationally exposed to diesel exhaust was performed to determine their internal burden of diesel associated aromatic compounds. Personal air sampling also allowed to determine the exposure of the miners at their work place towards several polycyclic aromatic hydrocarbons (PAH) and nitro-arenes, the latter of which are thought to be specific constituents of diesel exhaust. For biomonitoring the urine of 18 underground salt miners was collected during and after their shift for 24-hours. half of the 18 miners were smokers. The urinary levels of 1-hydroxypyrene and hydroxylated phenanthrene metabolites were determined as biomarkers of PAH exposure, whereas urinary levels of some aromatic amines were chosen to monitor exposure towards specific nitro-arenes from diesel exhaust like 1-nitropyrene and 3-nitrobenzanthrone and to monitor the human burden by these compounds from inhaled cigarette smoke. Non-smoking workers exposed to diesel exhaust excrete an average level of about 4 micrograms phenanthrene metabolites, whereas the urinary levels in smokers were up to 3-fold higher. In summary the results indicate that (i) diesel exposure led to an increase of PAH metabolism in the workers examined, most probably by an induction of cytochrome P450 (ii) smokers could be identified in accordance with earlier studies by their increased ratio of phenanthrene metabolites derived from 1,2- and 3,4-oxidation and their higher amounts of excreted 1-naphthylamine, and (iii) the excreted amounts of aromatic amines found as metabolites of the nitro-arenes were about 5- to 10-fold higher as one might expect from the levels determined by personal air sampling at the workplace of the individuals.

Physiological limit of the daily endogenous cholecalciferol synthesis from UV light in cattle.

PubMed

Hymøller, L; Jensen, S K; Kaas, P; Jakobsen, J

2017-04-01

The link between UV light (sunlight) and endogenous cholecalciferol (vitamin D 3 ) synthesis in the skin of humans has been known for more than a 100 years, since doctors for the first time successfully used UV light to cure rickets in children. Years later, it was shown that UV light also had a significant effect on the cholecalciferol status in the body of cattle. The cholecalciferol status in the body is measured as the plasma concentration of 25-hydroxycholecalciferol, which in cattle and humans is the major circulating metabolite of cholecalciferol. Very little is, however, known about the quantitative efficiency of UV light as a source of cholecalciferol in cattle nutrition and physiology. Hence, the aim of this study was to determine the efficiency of using UV light for increasing the plasma 25-hydroxycholecalciferol concentration in cholecalciferol-deprived cattle. Twelve cows deprived of cholecalciferol for 6 months were divided into three treatment groups and exposed to UV light for 30, 90 or 120 min/day during 28 days. UV-light wavelengths ranged from 280 to 415 nm and 30-min exposure to the UV light was equivalent to 60-min average summer-sunlight exposure at 56 °N. Blood samples were collected every 3-4 days and analysed for 25-hydroxycholecalciferol and cholecalciferol. Results showed that increasing the exposure time from 90-120 min/day did not change the slope of the daily increase in plasma 25-hydroxycholecalciferol. Hence, it appears that cholecalciferol-deprived dairy cattle are able to increase their plasma 25-hydroxycholecalciferol concentration by a maximum of 1 ng/ml/day from UV-light exposure. Journal of Animal Physiology and Animal Nutrition © 2016 Blackwell Verlag GmbH.

Inhalation Exposure to Dioxins and dl-PCBs Depending on the Season in Upper Silesia, Poland: A Pilot Study.

PubMed

Dziubanek, Grzegorz; Marchwińska, Ewa; Hajok, Ilona; Piekut, Agata

2016-06-01

The aim of this study was to investigate the seasonal fluctuation of PCDD/Fs and dl-PCBs levels in the ambient air of Upper Silesia in the aspect of human inhalation exposure as well as the estimation of health risk attributed to this exposure pathway to dioxins and dl-PCBs. In the study air samples were taken in five urban districts of Upper Silesia, Poland, where the houses are heated with coal. The same sampling points in summer and winter were analyzed for dioxins/furans and dl-PCBs. In addition, information was collected on awareness of the residents about the co-incineration of plastic waste and effects of this activity on human health. The results show that the average daily exposure of residents of Upper Silesia to TCDD and DLCs in the heating season was about 6.5.-fold higher than in summer. The risk assessment showed that expected excess of cancer cases per 1,000,000 people ranged from 4.5 to 13.2 in winter and from 0.9 to 2.1 in summer. The practice of mixing waste with coal for houses heating has been confirmed by investigated families, who do not associate it with the possibility of negative health effects. Air pollution can be a significant source of dioxin and dl-PCB for people during the winter season, as a result of co-burning coal and waste containing plastics. The dose of dioxins inhaled through the respiratory pathway in winter can be associated with the higher cancer risk in the population of Upper Silesia. Copyright© by the National Institute of Public Health, Prague 2015.

Human health risk assessment of the mixture of pharmaceuticals in Dutch drinking water and its sources based on frequent monitoring data.

PubMed

Houtman, Corine J; Kroesbergen, Jan; Lekkerkerker-Teunissen, Karin; van der Hoek, Jan Peter

2014-10-15

The presence of pharmaceuticals in drinking water is a topic of concern. Previous risk assessments indicate that their low concentrations are very unlikely to pose risks to human health, however often conclusions had to be based on small datasets and mixture effects were not included. The objectives of this study were to a) investigate if pharmaceuticals in surface and polder water penetrate in drinking water, b) assess the lifelong exposure of consumers to pharmaceuticals via drinking water and c) assess the possible individual and mixture health risks associated with this exposure. To fulfill these aims, a 2-year set of 4-weekly monitoring data of pharmaceuticals was used from three drinking water production plants. The 42 pharmaceuticals that were monitored were selected according to their consumption volume, earlier detection, toxicity and representation of the most relevant therapeutic classes. Lifelong exposures were calculated from concentrations and compared with therapeutic doses. Health risks were assessed by benchmarking concentrations with provisional guideline values. Combined risks of mixtures of pharmaceuticals were estimated using the concept of Concentration Addition. The lifelong exposure to pharmaceuticals via drinking water was calculated to be extremely low, i.e. a few mg, in total corresponding to <10% of the dose a patient is administered on one day. The risk of adverse health effects appeared to be negligibly low. Application of Concentration Addition confirmed this for the mixture of pharmaceuticals simultaneously present. The investigated treatment plants appeared to reduce the (already negligible) risk up to 80%. The large available monitoring dataset enabled the performance of a realistic risk assessment. It showed that working with maximum instead of average concentrations may overestimate the risk considerably. Copyright © 2014 Elsevier B.V. All rights reserved.

Characterizing the impact of projected changes in climate and air quality on human exposures to ozone.

PubMed

Dionisio, Kathie L; Nolte, Christopher G; Spero, Tanya L; Graham, Stephen; Caraway, Nina; Foley, Kristen M; Isaacs, Kristin K

2017-05-01

The impact of climate change on human and environmental health is of critical concern. Population exposures to air pollutants both indoors and outdoors are influenced by a wide range of air quality, meteorological, behavioral, and housing-related factors, many of which are also impacted by climate change. An integrated methodology for modeling changes in human exposures to tropospheric ozone (O 3 ) owing to potential future changes in climate and demographics was implemented by linking existing modeling tools for climate, weather, air quality, population distribution, and human exposure. Human exposure results from the Air Pollutants Exposure Model (APEX) for 12 US cities show differences in daily maximum 8-h (DM8H) exposure patterns and levels by sex, age, and city for all scenarios. When climate is held constant and population demographics are varied, minimal difference in O 3 exposures is predicted even with the most extreme demographic change scenario. In contrast, when population is held constant, we see evidence of substantial changes in O 3 exposure for the most extreme change in climate. Similarly, we see increases in the percentage of the population in each city with at least one O 3 exposure exceedance above 60 p.p.b and 70 p.p.b thresholds for future changes in climate. For these climate and population scenarios, the impact of projected changes in climate and air quality on human exposure to O 3 are much larger than the impacts of changing demographics. These results indicate the potential for future changes in O 3 exposure as a result of changes in climate that could impact human health.

Risk assessment of acrylamide in foods.

PubMed

Dybing, E; Sanner, T

2003-09-01

Daily mean intakes of acrylamide present in foods and coffee in a limited Norwegian exposure assessment study have been estimated to be 0.49 and 0.46 microg per kg body weight in males and females, respectively. Testicular mesotheliomas and mammary gland adenomas have consistently been found in 2-year drinking water rat cancer studies with acrylamide. Acrylamide also shows initiating activity in mouse skin after systemic administration. Since acrylamide is converted to the mutagenic metabolite glycidamide and forms adducts to hemoglobin in rodents and humans, the tumorigenic endpoints in rats were assumed to be an expression of acrylamide genotoxicity. Using the default linear extrapolation methods LED10 and T25, the lifetime cancer hazard after lifelong exposure to 1 microg acrylamide per kg body weight per day, scaled to humans, was calculated to be, on average, 1.3 x 10-3. Using this hazard level and correlating it with the exposure estimates, a lifetime cancer risk related to daily intake of acrylamide in foods for 70 years in males was calculated to be 0.6 x 10-3, implying that 6 out of 10,000 individuals may develop cancer due to acrylamide. For females, the risk values were slightly lower. It must be emphasized that this risk assessment is conservative. A number of processes may result in nonlinearity of the dose-response relationships for acrylamide carcinogenicity in the low-dose region, including detoxication reactions, cell cycle arrest, DNA repair, apoptosis, and immune surveillance. Thus, the true risk levels related to acrylamide intake may be considerably lower.

Preliminary Upper Estimate of Peak Currents in Transcranial Magnetic Stimulation at Distant Locations from a TMS Coil

PubMed Central

Makarov, Sergey N.; Yanamadala, Janakinadh; Piazza, Matthew W.; Helderman, Alex M.; Thang, Niang S.; Burnham, Edward H.; Pascual-Leone, Alvaro

2016-01-01

Goals Transcranial magnetic stimulation (TMS) is increasingly used as a diagnostic and therapeutic tool for numerous neuropsychiatric disorders. The use of TMS might cause whole-body exposure to undesired induced currents in patients and TMS operators. The aim of the present study is to test and justify a simple analytical model known previously, which may be helpful as an upper estimate of eddy current density at a particular distant observation point for any body composition and any coil setup. Methods We compare the analytical solution with comprehensive adaptive mesh refinement-based FEM simulations of a detailed full-body human model, two coil types, five coil positions, about 100,000 observation points, and two distinct pulse rise times, thus providing a representative number of different data sets for comparison, while also using other numerical data. Results Our simulations reveal that, after a certain modification, the analytical model provides an upper estimate for the eddy current density at any location within the body. In particular, it overestimates the peak eddy currents at distant locations from a TMS coil by a factor of 10 on average. Conclusion The simple analytical model tested in the present study may be valuable as a rapid method to safely estimate levels of TMS currents at different locations within a human body. Significance At present, safe limits of general exposure to TMS electric and magnetic fields are an open subject, including fetal exposure for pregnant women. PMID:26685221

Radiation risk estimation and its application to human beings in space.

PubMed

Sinclair, W K

1984-01-01

The number of human beings likely to spend time in space will increase as time goes on. While exposures vary according to missions, orbits, shielding, etc., an average space radiation fluence (ignoring solar flares, radiation belts and anomalous regions in space) in locations close to earth is about 10 rad/year with a quality factor of about 5.5. The potential effects of exposure to these fluences include both non-stochastic effects and stochastic effects (cancer and genetic damage). Non-stochastic effects, damage to the lens of the eye, bone marrow or gonads, can be avoided by keeping radiation limits below threshold values. Stochastic effects imply risk at all levels. The magnitude of these risks has been discussed in a number of reports by the UNSCEAR Committee and the BEIR Committee in the USA during 1970-1980. The uncertainties associated with these risks and information which has become available since the last BEIR report is discussed. In considering reasonable limits for exposure in space, acceptable levels for stochastic risks must be based on appropriate comparisons. In view of the limited term of duty of most space workers, a lifetime limit may be appropriate. This lifetime limit might be comparable in terms of risks with limits for radiation workers on the ground but received at a higher annual rate for a shorter time. These and other approaches are expected to be considered by an NCRP Committee currently examining the problem of space radiation hazards.

Dioxin equivalency: Challenge to dose extrapolation

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

Brown, J.F. Jr.; Silkworth, J.B.

1995-12-31

Extensive research has shown that all biological effects of dioxin-like agents are mediated via a single biochemical target, the Ah receptor (AhR), and that the relative biologic potencies of such agents in any given system, coupled with their exposure levels, may be described in terms of toxic equivalents (TEQ). It has also shown that the TEQ sources include not only chlorinated species such as the dioxins (PCDDs), PCDFs, and coplanar PCBs, but also non-chlorinated substances such as the PAHs of wood smoke, the AhR agonists of cooked meat, and the indolocarbazol (ICZ) derived from cruciferous vegetables. Humans have probably hadmore » elevated exposures to these non-chlorinated TEQ sources ever since the discoveries of fire, cooking, and the culinary use of Brassica spp. Recent assays of CYP1A2 induction show that these ``natural`` or ``traditional`` AhR agonists are contributing 50--100 times as much to average human TEQ exposures as do the chlorinated xenobiotics. Currently, the safe doses of the xenobiotic TEQ sources are estimated from their NOAELs and large extrapolation factors, derived from arbitrary mathematical models, whereas the NOAELs themselves are regarded as the safe doses for the TEQs of traditional dietary components. Available scientific data can neither support nor refute either approach to assessing the health risk of an individual chemical substance. However, if two substances be toxicologically equivalent, then their TEQ-adjusted health risks must also be equivalent, and the same dose extrapolation procedure should be used for both.« less

Asbestos exposure from the overhaul of a Pratt & Whitney R2800 engine.

PubMed

Mlynarek, S P; Van Orden, D R

2012-11-01

This study assessed the asbestos exposures of airplane piston engine mechanics while performing overhaul work on a Pratt & Whitney R2800 radial engine, with tools and practices in use since the time these engines were manufactured. Approximately 40% of the bulk samples collected during this test were found to contain chrysotile. Air samples were collected during the overhaul and were analyzed by phase contrast microscopy (PCM) and transmission electron microscopy (TEM). The average worker exposure during disassembly was 0.0272f/ml (PCM) and ranged from 0.0013 to 0.1240f/ml (PCM) during an average sample collection time of 188min. The average worker exposure during reassembly was 0.0198f/ml (PCM) and ranged from 0.0055 to 0.0913f/ml (PCM) during an average sample collection time of 222min. Only one worker sample (during reassembly) was found to contain asbestos at a concentration of 0.0012f/ml (PCME). Similar results should be found in other aircraft piston engines that use metal clad and non-friable asbestos gaskets, which are the current standard in aircraft piston engines. Copyright © 2012 Elsevier Inc. All rights reserved.

Specific absorption rate and electric field measurements in the near field of six mobile phone base station antennas.

PubMed

Toivonen, Tommi; Toivo, Tim; Puranen, Lauri; Jokela, Kari

2009-05-01

In this article, the exposure to radio frequency electromagnetic fields was studied in close proximity (distances of 10, 100, 300, and 600 mm) to six base station antennas. The specific absorption rate (SAR) in 800 mm x 500 mm x 200 mm box phantom as well as unperturbed electric field (E) in air was measured. The results were used to determine whether the measurement of local maximum of unperturbed electric field can be used as a compliance check for local exposure. Also, the conservativeness of this assessment method compared to the ICNIRP basic restriction was studied. Moreover, the assessment of whole-body exposure was discussed and the distance ranges presented in which the ICNIRP limit for local exposure could be exceeded before the limit for whole-body SAR. These results show that the electric field measurement alone can be used for easy compliance check for the local exposure at all distances and for all antenna types studied. However, in some cases when the local peak value of E was compared directly to the ICNIRP reference level for unperturbed E, the exposure was overestimated only very slightly (by factor 1.1) compared to the basic restriction for localized SAR in a human, and hence these results can not be generalized to all antenna types. Moreover, it was shown that the limit for localized exposure could be exceeded before the limit for the whole-body average SAR, if the distance to the antenna was less than 240 mm. Copyright 2009 Wiley-Liss, Inc.

Prevalence and predictors of phthalate exposure in pregnant women in Charleston, SC.

PubMed

Wenzel, Abby G; Brock, John W; Cruze, Lori; Newman, Roger B; Unal, Elizabeth R; Wolf, Bethany J; Somerville, Stephen E; Kucklick, John R

2018-02-01

Phthalates are plasticizers commonly detected in human urine due to widespread exposure from PVC plastics, food packaging, and personal care products. Several phthalates are known antiandrogenic endocrine disruptors, which raises concern for prenatal exposure during critical windows of fetal development. While phthalate exposure is ubiquitous, certain demographics are subject to greater or lesser exposure. We sampled urine from 378 pregnant women during the second trimester of gestation living in Charleston, SC, and measured eight urinary phthalate metabolites as biomarkers of phthalate exposure: monobutyl phthalate (MBP), monobenzyl phthalate (MBzP), mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), monoethyl phthalate (MEP), monoisobutyl phthalate (MiBP), and monomethyl phthalate (MMP). Demographic data was collected from questionnaires administered at the time of specimen collection. All phthalate metabolites were detected in over 93% of urine samples. On average, concentrations were highest for MEP (median = 47.0 ng/mL) and lowest for MMP (median = 1.92 ng/mL). Sociodemographic characteristics associated with elevated phthalate concentrations included being unmarried, less educated, having a low income, high body mass index (BMI), and/or being African American. After racial stratification, age, BMI, education, and income were significantly associated with phthalate concentrations in African American women. Marital status was associated with phthalate concentrations in Caucasian women only, with greater concentrations of MBP, MEHHP, MiBP, and MMP in unmarried versus married women. Results of this cross-sectional study provide evidence for significant racial and demographic variations in phthalate exposure. Copyright © 2017 Elsevier Ltd. All rights reserved.

Serum vitamin D levels are not altered after controlled diesel ...

EPA Pesticide Factsheets

Past research has suggested that exposure to urban air pollution may be associated with vitamin D deficiency in human populations. Vitamin D is widely known for its importance in bone growth/remodeling, muscle metabolism, and its ability to promote calcium absorption in the gut; deficiency in vitamin D results in the development of rickets in children and osteomalacia in adults. In the current study, we assessed whether vitamin D levels are altered under controlled exposures to a commonly measured urban air pollutant, diesel. For this study, we exposed 12 healthy volunteers to clean air and diesel exhaust (300 μg/m3) for 2 hours while undergoing intermittent exercise. Venous blood was collected before, 0 hrs post-, and 18 hrs post-exposure, and 25-hydroxyvitamin D [25(OH)D] was measured in the serum. The average baseline value of 25(OH)D (mean ± standard error) was 22.9 ± 2.5 ng/mL. Four subject’s baseline values were vitamin D deficient (30 ng/mL). Additionally, there was no significant change in the baseline values between the clean air and diesel exposures (paired t-test, p = 0.54), suggesting minimal variability in 25(OH)D over the experiment's time course. Small inductions in 25(OH)D were found following clean air exposures (12.5 ± 4.9% and a 7.1 ± 5.0% for 0 hrs post- and 18 hrs post-exposure values compared to baseline, respectively). Minimal changes in 25(OH)D were observed following diesel exhaust exposures 0 hrs (3.5 ± 5.2%) and 18 hrs followin

40 CFR 158.2270 - Post-application exposure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and the human activities associated with the pesticide's use pattern can lead to potential adverse...) Occupational human post-application or bystander exposure to residues of antimicrobial pesticides could occur... human post-application or bystander exposure to residues of antimicrobial pesticides could occur...

40 CFR 158.2270 - Post-application exposure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and the human activities associated with the pesticide's use pattern can lead to potential adverse...) Occupational human post-application or bystander exposure to residues of antimicrobial pesticides could occur... human post-application or bystander exposure to residues of antimicrobial pesticides could occur...

IMMUNOASSAY HUMAN EXPOSURE STUDIES

EPA Science Inventory

The Human Exposure Research Branch has developed several enzyme-linked immunosorbent assay (ELISA) methods to support human exposure assessment studies. Immunoassays to detect low levels (<10 ng/mL) of chlorpyrifos in food, track-in dirt and house dust have been applied to sam...

POPULATION EXPOSURE AND DOSE MODEL FOR AIR TOXICS: A BENZENE CASE STUDY

EPA Science Inventory

The EPA's National Exposure Research Laboratory (NERL) is developing a human exposure and dose model called the Stochastic Human Exposure and Dose Simulation model for Air Toxics (SHEDS-AirToxics) to characterize population exposure to air toxics in support of the National Air ...

Personalized Exposure Assessment: Promising Approaches for Human Environmental Health Research

PubMed Central

Weis, Brenda K.; Balshaw, David; Barr, John R.; Brown, David; Ellisman, Mark; Lioy, Paul; Omenn, Gilbert; Potter, John D.; Smith, Martyn T.; Sohn, Lydia; Suk, William A.; Sumner, Susan; Swenberg, James; Walt, David R.; Watkins, Simon; Thompson, Claudia; Wilson, Samuel H.

2005-01-01

New technologies and methods for assessing human exposure to chemicals, dietary and lifestyle factors, infectious agents, and other stressors provide an opportunity to extend the range of human health investigations and advance our understanding of the relationship between environmental exposure and disease. An ad hoc Committee on Environmental Exposure Technology Development was convened to identify new technologies and methods for deriving personalized exposure measurements for application to environmental health studies. The committee identified a “toolbox” of methods for measuring external (environmental) and internal (biologic) exposure and assessing human behaviors that influence the likelihood of exposure to environmental agents. The methods use environmental sensors, geographic information systems, biologic sensors, toxicogenomics, and body burden (biologic) measurements. We discuss each of the methods in relation to current use in human health research; specific gaps in the development, validation, and application of the methods are highlighted. We also present a conceptual framework for moving these technologies into use and acceptance by the scientific community. The framework focuses on understanding complex human diseases using an integrated approach to exposure assessment to define particular exposure–disease relationships and the interaction of genetic and environmental factors in disease occurrence. Improved methods for exposure assessment will result in better means of monitoring and targeting intervention and prevention programs. PMID:16002370

Radiation as a Risk Factor for Cardiovascular Disease

PubMed Central

Moulder, John E.; Hopewell, John W.

2011-01-01

Abstract Humans are continually exposed to ionizing radiation from terrestrial sources. The two major contributors to radiation exposure of the U.S. population are ubiquitous background radiation and medical exposure of patients. From the early 1980s to 2006, the average dose per individual in the United States for all sources of radiation increased by a factor of 1.7–6.2 mSv, with this increase due to the growth of medical imaging procedures. Radiation can place individuals at an increased risk of developing cardiovascular disease. Excess risk of cardiovascular disease occurs a long time after exposure to lower doses of radiation as demonstrated in Japanese atomic bomb survivors. This review examines sources of radiation (atomic bombs, radiation accidents, radiological terrorism, cancer treatment, space exploration, radiosurgery for cardiac arrhythmia, and computed tomography) and the risk for developing cardiovascular disease. The evidence presented suggests an association between cardiovascular disease and exposure to low-to-moderate levels of radiation, as well as the well-known association at high doses. Studies are needed to define the extent that diagnostic and therapeutic radiation results in increased risk factors for cardiovascular disease, to understand the mechanisms involved, and to develop strategies to mitigate or treat radiation-induced cardiovascular disease. Antioxid. Redox Signal. 15, 1945–1956. PMID:21091078

Body heating induced by sub-resonant (350 MHz) microwave irradiation: cardiovascular and respiratory responses in anesthetized rats.

PubMed

Jauchem, J R; Frei, M R

1997-01-01

These experiments were designed to investigate the effects of sub-resonant microwave (MW) exposure (350 MHz, E orientation, average power density 38 mW/cm2, average whole-body specific absorption rate 13.2 W/kg) on selected physiological parameters. The increase in peripheral body temperature during 350 MHz exposure was greater than that in earlier experiments performed at 700 MHz (resonance). Heart rate and mean arterial blood pressure were significantly elevated during a 1 degree C increase in colonic temperature due to 350 MHz exposure; respiratory rate showed no significant change. The results are consistent with other investigators' reports comparing sub-resonance exposures with those at resonance and above.

Sequential Neighborhood Effects: The Effect of Long-Term Exposure to Concentrated Disadvantage on Children's Reading and Math Test Scores.

PubMed

Hicks, Andrew L; Handcock, Mark S; Sastry, Narayan; Pebley, Anne R

2018-02-01

Prior research has suggested that children living in a disadvantaged neighborhood have lower achievement test scores, but these studies typically have not estimated causal effects that account for neighborhood choice. Recent studies used propensity score methods to account for the endogeneity of neighborhood exposures, comparing disadvantaged and nondisadvantaged neighborhoods. We develop an alternative propensity function approach in which cumulative neighborhood effects are modeled as a continuous treatment variable. This approach offers several advantages. We use our approach to examine the cumulative effects of neighborhood disadvantage on reading and math test scores in Los Angeles. Our substantive results indicate that recency of exposure to disadvantaged neighborhoods may be more important than average exposure for children's test scores. We conclude that studies of child development should consider both average cumulative neighborhood exposure and the timing of this exposure.

Estimation of the diesel exhaust exposures of railroad workers: II. National and historical exposures.

PubMed

Woskie, S R; Smith, T J; Hammond, S K; Schenker, M B; Garshick, E; Speizer, F E

1988-01-01

The diesel exhaust exposures of railroad workers in thirteen job groups from four railroads in the United States were used to estimate U.S. national average exposures with a linear statistical model which accounts for the significant variability in exposure caused by climate, the differences among railroads and the uneven distribution of railroad workers across climatic regions. Personal measurements of respirable particulate matter, adjusted to remove the contribution of cigarette smoke particles, were used as a marker for diesel exhaust. The estimated national means of adjusted respirable particulate matter (ARP) averaged 10 micrograms/m3 lower than the simple means for each job group, reflecting the climatic differences between the northern railroads studied and the distribution of railroad workers nationally. Limited historical records, including some industrial hygiene data, were used to evaluate past diesel exhaust exposures, which were estimated to be approximately constant from the 1950's to 1983.

Sequential Neighborhood Effects: The Effect of Long-Term Exposure to Concentrated Disadvantage on Children's Reading and Math Test Scores

PubMed Central

Hicks, Andrew L.; Handcock, Mark S.; Sastry, Narayan

2018-01-01

Prior research has suggested that children living in a disadvantaged neighborhood have lower achievement test scores, but these studies typically have not estimated causal effects that account for neighborhood choice. Recent studies used propensity score methods to account for the endogeneity of neighborhood exposures, comparing disadvantaged and nondisadvantaged neighborhoods. We develop an alternative propensity function approach in which cumulative neighborhood effects are modeled as a continuous treatment variable. This approach offers several advantages. We use our approach to examine the cumulative effects of neighborhood disadvantage on reading and math test scores in Los Angeles. Our substantive results indicate that recency of exposure to disadvantaged neighborhoods may be more important than average exposure for children's test scores. We conclude that studies of child development should consider both average cumulative neighborhood exposure and the timing of this exposure. PMID:29192386

Return to Flying Duties Following Centrifuge or Vibration Exposures

NASA Technical Reports Server (NTRS)

Scheuring, Richard A.; Clarke, Jonathan; Jones, Jeffrey A.

2009-01-01

Introduction: In an effort to determine the human performance limits for vibration in spacecraft being developed by NASA, astronauts were evaluated during a simulated launch profile in a centrifuge/vibration environment and separate vibration-only simulation. Current USAF and Army standards for return to flight following centrifuge exposures require 12-24 hours to pass before a crewmember may return to flying duties. There are no standards on vibration exposures and return to flying duties. Based on direct observation and provocative neurological testing of the astronauts, a new standard for return to flying duties following centrifuge and/or vibration exposures was established. Methods: 13 astronaut participants were exposed to simulated launch profiles in a + 3.5 Gx bias centrifuge/vibration environment and separately on a vibration table at the NASA-Ames Research Center. Each subject had complete neurological evaluations pre- and post-exposure for the centrifuge/vibration runs with the NASA neurological function rating scale (NFRS). Subjects who participated in the vibration-only exposures had video oculography performed with provocative maneuvers in addition to the NFRS. NFRS evaluations occurred immediately following each exposure and at 1 hour post-run. Astronauts who remained symptomatic at 1 hour had repeat NFRS performed at 1 hour intervals until the crewmember was asymptomatic. Results: Astronauts in the centrifuge/vibration study averaged a 3-5 point increase in NFRS scores immediately following exposure but returned to baseline 3 hours post-run. Subjects exposed to the vibration-only simulation had a 1-3 point increase following exposure and returned to baseline within 1-2 hours. Pre- and post- vibration exposure video oculography did not reveal any persistent ocular findings with provocative testing 1 hour post-exposure. Discussion: Based on direct observations and objective measurement of neurological function in astronauts following simulated launch profiles, asymptomatic individuals are allowed to return to flying duties within 3 hours following centrifuge/vibration and 2 hours after vibration-only exposures.

D-cycloserine Enhancement of Exposure Therapy for Social Anxiety Disorder Depends on the Success of Exposure Sessions

PubMed Central

Smits, Jasper A. J.; Rosenfield, David; Otto, Michael W.; Marques, Luana; Davis, Michelle L.; Meuret, Alicia E.; Simon, Naomi M.; Pollack, Mark H.; Hofmann, Stefan G.

2013-01-01

Objective The evidence for the efficacy of D-cycloserine (DCS) for augmenting cognitive behavioral therapy (CBT) for anxiety disorders has been mixed. Guided by preclinical research and initial findings from a small-scale study involving humans, we tested the hypothesis that DCS enhancement of exposure therapy would be specific to successful exposure sessions. Method Medication-free adults with generalized social anxiety disorder (N = 145) received 50 mg of DCS or placebo 1 hour before each of 5 exposure sessions that were part of a standardized 12-session group CBT protocol. Participants provided fear ratings at the beginning and just before the end of exposure exercises. Independent raters, blind to group assignment, administered the clinical global impression improvement and severity scales at each session and at posttreatment. Results Mixed-effects analyses revealed that, among patients who reported low fear at the end of an exposure session, those who had received DCS evidenced significantly greater clinical improvement at the next session, relative to those who had received placebo. In contrast, when exposure end fear was high, patients receiving DCS exhibited less clinical improvement at the following session than patients receiving placebo. Similarly, patients who had received DCS evidenced lower clinical severity at posttreatment, relative to patients who had received placebo, only when their average end fear for medication-augmented sessions had been in the low to moderate range. Finally, these moderating effects of exposure success as indexed by end fear were not better accounted for by within-session extinction. Conclusions The efficacy of DCS for augmenting exposure-based CBT depends on the success of exposure sessions. These findings may help guide the development of an algorithm for the effective use of DCS for augmenting exposure-based CBT. Trial Registry http://www.ClinicalTrials.gov, ID# NCT00633984, http://www.clinicaltrials.gov/ct2/show/NCT00633984 PMID:23870811

Evaluating methods for estimating space-time paths of individuals in calculating long-term personal exposure to air pollution

NASA Astrophysics Data System (ADS)

Schmitz, Oliver; Soenario, Ivan; Vaartjes, Ilonca; Strak, Maciek; Hoek, Gerard; Brunekreef, Bert; Dijst, Martin; Karssenberg, Derek

2016-04-01

Air pollution is one of the major concerns for human health. Associations between air pollution and health are often calculated using long-term (i.e. years to decades) information on personal exposure for each individual in a cohort. Personal exposure is the air pollution aggregated along the space-time path visited by an individual. As air pollution may vary considerably in space and time, for instance due to motorised traffic, the estimation of the spatio-temporal location of a persons' space-time path is important to identify the personal exposure. However, long term exposure is mostly calculated using the air pollution concentration at the x, y location of someone's home which does not consider that individuals are mobile (commuting, recreation, relocation). This assumption is often made as it is a major challenge to estimate space-time paths for all individuals in large cohorts, mostly because limited information on mobility of individuals is available. We address this issue by evaluating multiple approaches for the calculation of space-time paths, thereby estimating the personal exposure along these space-time paths with hyper resolution air pollution maps at national scale. This allows us to evaluate the effect of the space-time path and resulting personal exposure. Air pollution (e.g. NO2, PM10) was mapped for the entire Netherlands at a resolution of 5×5 m2 using the land use regression models developed in the European Study of Cohorts for Air Pollution Effects (ESCAPE, http://escapeproject.eu/) and the open source software PCRaster (http://www.pcraster.eu). The models use predictor variables like population density, land use, and traffic related data sets, and are able to model spatial variation and within-city variability of annual average concentration values. We approximated space-time paths for all individuals in a cohort using various aggregations, including those representing space-time paths as the outline of a persons' home or associated parcel of land, the 4 digit postal code area or neighbourhood of a persons' home, circular areas around the home, and spatial probability distributions of space-time paths during commuting. Personal exposure was estimated by averaging concentrations over these space-time paths, for each individual in a cohort. Preliminary results show considerable differences of a persons' exposure using these various approaches of space-time path aggregation, presumably because air pollution shows large variation over short distances.

A Modeling Investigation of Human Exposure to Select Traffic-Related Air Pollutants in the Tampa Area: Spatiotemporal Distributions of Concentrations, Social Distributions of Exposures, and Impacts of Urban Design on Both

NASA Astrophysics Data System (ADS)

Yu, Haofei

Increasing vehicle dependence in the United States has resulted in substantial emissions of traffic-related air pollutants that contribute to the deterioration of urban air quality. Exposure to urban air pollutants trigger a number of public health concerns, including the potential of inequality of exposures and health effects among population subgroups. To better understand the impact of traffic-related pollutants on air quality, exposure, and exposure inequality, modeling methods that can appropriately characterize the spatiotemporally resolved concentration distributions of traffic-related pollutants need to be improved. These modeling methods can then be used to investigate the impacts of urban design and transportation management choices on air quality, pollution exposures, and related inequality. This work will address these needs with three objectives: 1) to improve modeling methods for investigating interactions between city and transportation design choices and air pollution exposures, 2) to characterize current exposures and the social distribution of exposures to traffic-related air pollutants for the case study area of Hillsborough County, Florida, and 3) to determine expected impacts of urban design and transportation management choices on air quality, air pollution exposures, and exposure inequality. To achieve these objectives, the impacts of a small-scale transportation management project, specifically the '95 Express' high occupancy toll lane project, on pollutant emissions and nearby air quality was investigated. Next, a modeling method capable of characterizing spatiotemporally resolved pollutant emissions, concentrations, and exposures was developed and applied to estimate the impact of traffic-related pollutants on exposure and exposure inequalities among several population subgroups in Hillsborough County, Florida. Finally, using these results as baseline, the impacts of sprawl and compact urban forms, as well as vehicle fleet electrification, on air quality, pollution exposure, and exposure inequality were explored. Major findings include slightly higher pollutant emissions, with the exception of hydrocarbons, due to the managed lane project. Results also show that ambient concentration contributions from on-road mobile sources are disproportionate to their emissions. Additionally, processes not captured by the CALPUFF model, such as atmospheric formation, contribute substantially to ambient concentration levels of the secondary pollutants such as acetaldehyde and formaldehyde. Exposure inequalities for NOx, 1,3-butadiene, and benzene air pollution were found for black, Hispanic, and low income (annual household income less than $20,000) subgroups at both short-term and long-term temporal scales, which is consistent with previous findings. Exposure disparities among the subgroups are complex, and sometimes reversed for acetaldehyde and formaldehyde, due primarily to their distinct concentration distributions. Compact urban form was found to result in lower average NOx and benzene concentrations, but higher exposure for all pollutants except for NOx when compared to sprawl urban form. Evidence suggests that exposure inequalities differ between sprawl and compact urban forms, and also differ by pollutants, but are generally consistent at both short and long-term temporal scales. In addition, vehicle fleet electrification was found to result in generally lower average pollutant concentrations and exposures, except for NOx. However, the elimination of on-road mobile source emissions does not substantially reduce exposure inequality. Results and findings from this work can be applied to assist transportation infrastructure and urban planning. In addition, method developed here can be applied elsewhere for better characterization of air pollution concentrations, exposure and related inequalities.

Unhealthy Behaviours: An International Comparison

PubMed Central

Ferretti, Fabrizio

2015-01-01

In the current global economy, chronic non-communicable diseases (NCDs) have become the leading cause of death and a major health concern for both developed and developing countries. Among other factors, the worldwide spread of NCDs is driven by the globalisation of unhealthy habits. The purpose of this paper is to develop a simple statistic to measure, at the national level, the average population’s exposure to the main NCDs modifiable risk factors. The approach and methodology followed by the United Nations Development Programme to compute the Human Development Index (HDI) is applied to four basic indicators of NCD-related preventable risk factors (alcohol consumption, excess caloric intake, non-balanced diet and tobacco use) in 112 countries worldwide in 2012–14. We obtain a summary composite index, which we call the Unhealthy Behaviour Index (UBI), which ranks countries by the average level of the unhealthy habits (drinking, eating and smoking) of their populations. We find that Belarus and Russian federation are the two countries with the unhealthiest NCD-related lifestyle. With the exception of Canada, the first twenty populations more exposed to the main NCDs preventable risk factors all live in European countries, and mainly in countries of Eastern Europe. Overall, the UBI tends to increase along with the level of human development. In medium, high and very high HDI countries, however, the same level of human development may be associated with very different kinds of NCD-related lifestyles. Finally, economic growth may push populations toward either more unhealthy or healthy habits, depending on the countries’ level of development; the elasticity of unhealthy habits with respect to income per capita is positive (but less than one: on average 0.6) until $30,000, decreases as income rises, and becomes negative (around -0.3) in very high income countries. PMID:26512717

Unhealthy Behaviours: An International Comparison.

PubMed

Ferretti, Fabrizio

2015-01-01

In the current global economy, chronic non-communicable diseases (NCDs) have become the leading cause of death and a major health concern for both developed and developing countries. Among other factors, the worldwide spread of NCDs is driven by the globalisation of unhealthy habits. The purpose of this paper is to develop a simple statistic to measure, at the national level, the average population's exposure to the main NCDs modifiable risk factors. The approach and methodology followed by the United Nations Development Programme to compute the Human Development Index (HDI) is applied to four basic indicators of NCD-related preventable risk factors (alcohol consumption, excess caloric intake, non-balanced diet and tobacco use) in 112 countries worldwide in 2012-14. We obtain a summary composite index, which we call the Unhealthy Behaviour Index (UBI), which ranks countries by the average level of the unhealthy habits (drinking, eating and smoking) of their populations. We find that Belarus and Russian federation are the two countries with the unhealthiest NCD-related lifestyle. With the exception of Canada, the first twenty populations more exposed to the main NCDs preventable risk factors all live in European countries, and mainly in countries of Eastern Europe. Overall, the UBI tends to increase along with the level of human development. In medium, high and very high HDI countries, however, the same level of human development may be associated with very different kinds of NCD-related lifestyles. Finally, economic growth may push populations toward either more unhealthy or healthy habits, depending on the countries' level of development; the elasticity of unhealthy habits with respect to income per capita is positive (but less than one: on average 0.6) until $30,000, decreases as income rises, and becomes negative (around -0.3) in very high income countries.

Operation of the computer model for microenvironment atomic oxygen exposure

NASA Technical Reports Server (NTRS)

Bourassa, R. J.; Gillis, J. R.; Gruenbaum, P. E.

1995-01-01

A computer model for microenvironment atomic oxygen exposure has been developed to extend atomic oxygen modeling capability to include shadowing and reflections. The model uses average exposure conditions established by the direct exposure model and extends the application of these conditions to treat surfaces of arbitrary shape and orientation.

SOURCES OF HUMAN EXPOSURE TO AIRBORNE PAH

EPA Science Inventory

Personal exposures to airborne particulate polycyclic aromatic hydrocarbons (PAHs) were studied in several populations in the US, Japan, and Czech Republic. Personal exposure monitors, developed for human exposure biomonitoring studies were used to collect fine particles (<_ 1....

Characterizing climate change impacts on human exposures to air pollutants

EPA Science Inventory

Human exposures to air pollutants such as ozone (O3) have the potential to be altered by changes in climate through multiple factors that drive population exposures, including: ambient pollutant concentrations, human activity patterns, population sizes and distributions, and hous...

A NEW METHOD OF LONGITUDINAL DIARY ASSEMBLY FOR HUMAN EXPOSURE MODELING

EPA Science Inventory

Human exposure time-series modeling requires longitudinal time-activity diaries to evaluate the sequence of concentrations encountered, and hence, pollutant exposure for the simulated individuals. However, most of the available data on human activities are from cross-sectional su...

Exposure of U.S. National Parks to land use and climate change 1900-2100.

PubMed

Hansen, Andrew J; Piekielek, Nathan; Davis, Cory; Haas, Jessica; Theobald, David M; Gross, John E; Monahan, William B; Olliff, Tom; Running, Steven W

2014-04-01

Many protected areas may not be adequately safeguarding biodiversity from human activities on surrounding lands and global change. The magnitude of such change agents and the sensitivity of ecosystems to these agents vary among protected areas. Thus, there is a need to assess vulnerability across networks of protected areas to determine those most at risk and to lay the basis for developing effective adaptation strategies. We conducted an assessment of exposure of U.S. National Parks to climate and land use change and consequences for vegetation communities. We first defined park protected-area centered ecosystems (PACEs) based on ecological principles. We then drew on existing land use, invasive species, climate, and biome data sets and models to quantify exposure of PACEs from 1900 through 2100. Most PACEs experienced substantial change over the 20th century (> 740% average increase in housing density since 1940, 13% of vascular plants are presently nonnative, temperature increase of 1 degree C/100 yr since 1895 in 80% of PACEs), and projections suggest that many of these trends will continue at similar or increasingly greater rates (255% increase in housing density by 2100, temperature increase of 2.5 degrees-4.5 degrees C/100 yr, 30% of PACE areas may lose their current biomes by 2030). In the coming century, housing densities are projected to increase in PACEs at about 82% of the rate of since 1940. The rate of climate warming in the coming century is projected to be 2.5-5.8 times higher than that measured in the past century. Underlying these averages, exposure of individual park PACEs to change agents differ in important ways. For example, parks such as Great Smoky Mountains exhibit high land use and low climate exposure, others such as Great Sand Dunes exhibit low land use and high climate exposure, and a few such as Point Reyes exhibit high exposure on both axes. The cumulative and synergistic effects of such changes in land use, invasives, and climate are expected to dramatically impact ecosystem function and biodiversity in national parks. These results are foundational to developing effective adaptation strategies and suggest policies to better safeguard parks under broad-scale environmental change.

Permeation Resistance of Personal Protective Equipment Materials to Monomethyhydrazine

NASA Technical Reports Server (NTRS)

Waller, J. M.; Williams, J. H.

1997-01-01

Permeation resistance was determined by measuring the breakthrough time and time-averaged vapor transmission rate of monomethylhydrazine (MMH) through two types of personal protective equipment (PPE). The two types of PPE evaluated were the totally encapsulating ILC Dover Chemturion Model 1212 chemical protective suit with accessories, and the FabOhio polyvinyl chloride (PVC) splash garment. Two exposure scenarios were simulated: (1) a saturated vapor exposure for 2 hours (h), and (2) a brief MMH 'splash' followed by a 2-h saturated vapor exposure. Time-averaged MMH concentrations inside the totally-encapsulating suit were calculated by summation of the area-weighted contributions made by each suit component. Results show that the totally encapsulating suit provides adequate protection at the new 10 ppb Threshold Limit Value Time-Weighted Average (TLV-TWA). The permeation resistance of the PVC splash garment to MMH was poorer than any of the totally encapsulating suit materials tested. Breakthrough occurred soon after initial vapor or 'splash' exposure.

Indoor molds and lung function in healthy adults.

PubMed

Hernberg, Samu; Sripaiboonkij, Penpatra; Quansah, Reginald; Jaakkola, Jouni J K; Jaakkola, Maritta S

2014-05-01

Indoor mold exposure is common worldwide and constitutes an important health problem. There are very few studies assessing the relation between mold exposure and lung function levels among non-asthmatic adults. Our objective was to assess the relations between dampness and mold exposures at home and at work and lung function. In particular, we elaborated the importance of different exposure indicators. In a population-based study, 269 non-asthmatic adults from South Finland answered a questionnaire on indoor dampness and mold exposures at home or at work and other factors potentially influencing lung function, and performed spirometry. Multiple linear regression model was applied to study the relations between exposures and spirometric lung function levels. In linear regression adjusting for confounding, FEV1 level was reduced on average 200 ml related to mold odor at home (effect estimate -0.20, 95% CI -0.60 to 0.21) and FVC level was reduced on average 460 ml (-0.46, -0.95 to 0.03) respectively. Exposure to mold odor at home or at work or both was related to reduced FEV1 (-0.15, -0.42 to 0.12) and FVC (-0.22, -0.55 to 0.11) levels. Women had on average 510 ml reduced FEV1 levels (-0.51, -1.0 to 0.03) and 820 ml reduced FVC levels (-0.82, -1.4 to -0.20) related to mold odor exposure at home. Mold odor exposure was related to lower lung function levels among non-asthmatic adults, especially among women. Copyright © 2014 Elsevier Ltd. All rights reserved.

Monitoring of solar-UV exposure among schoolchildren in five Japanese cities using spore dosimeter and UV-coloring labels.

PubMed

Munakata, N; Ono, M; Watanabe, S

1998-03-01

To monitor personal exposure to biologically effective solar-UV radiation, Bacillus subtilis spores on a membrane filter and UV-coloring labels were incorporated into a monitoring badge. The samples were covered with one of three types of filter sheet, dependent on the season, to reduce the amounts of exposure to measurable levels. Five fifth- or sixth-grade classes of primary schools, each consisting of 30-40 children, were chosen in northern (Sapporo), central (Tsukuba and Tokyo), and southern (Miyazaki and Naha) cities in Japan. In all four season, each child wore a badge on an upper arm for the entire waking hours, changing it daily, for a week. Upon collection of the badges, the survival of spores and the extent of coloration of the label were determined. The results were used to estimate the amount of daily exposure to biologically effective UV radiation, expressed as the value of spore inactivation dose. Unexpectedly, the average amounts of exposure were not directly correlated with the outdoor UV irradiance: in the two southern cities, despite high outdoor irradiance from spring to autumn, the average amounts of exposure were less than 3.1% of the average irradiance. Highly concentrated exposures occurred in two central cities on three days when extensive outdoor exercise took place. These results contradict the simple notion that children's exposure is in proportion to the outdoor UV irradiance, and support the view that the extent of solar-UV exposure is primarily determined by life-style rather than living location.

Monitoring of Solar‐UV Exposure among Schoolchildren in Five Japanese Cities Using Spore Dosimeter and UV‐coloring Labels

PubMed Central

Ono, Masashi; Watanabe, Shaw

1998-01-01

To monitor personal exposure to biologically effective solar‐UV radiation, Bacillus subtilis spores on a membrane filter and UV‐coloring labels were incorporated into a monitoring badge. The samples were covered with one of three types of filter sheet, dependent on the season, to reduce the amounts of exposure to measurable levels. Five fifth‐ or sixth‐grade classes of primary schools, each consisting of 30–40 children, were chosen in northern (Sapporo), central (Tsukuba and Tokyo), and southern (Miyazaki and Naha) cities in Japan. In all four seasons, each child wore a badge on an upper arm for the entire waking hours, changing it daily, for a week. Upon collection of the badges, the survival of spores and the extent of coloration of the label were determined. The results were used to estimate the amount of daily exposure to biologically effective UV radiation, expressed as the value of spore inactivation dose. Unexpectedly, the average amounts of exposure were not directly correlated with the outdoor UV irradiance: in the two southern cities, despite high outdoor irradiance from spring to autumn, the average amounts of exposure were less than 3.1% of the average irradiance. Highly concentrated exposures occurred in two central cities on three days when extensive outdoor exercise took place. These results contradict the simple notion that childrens' exposure is in proportion to the outdoor UV irradiance, and support the view that the extent of solar‐UV exposure is primarily determined by life‐style rather than living location. PMID:9600116

Aflatoxin M1 in human breast milk in southeastern Turkey.

PubMed

Kılıç Altun, Serap; Gürbüz, Semra; Ayağ, Emin

2017-05-01

This study was performed to determine aflatoxin M 1 (AFM 1 ) in human breast milk samples collected in Şanlıurfa, located in Southeastern region of Turkey, and to investigate a possible correlation between AFM 1 occurrence (frequency and levels) and sampling seasons. Human breast milk samples collected in December 2014 and in June 2015 from a total of 74 nursing women, both outpatient and inpatient volunteers in hospitals located in Şanlıurfa, Turkey, were analyzed using competitive enzyme-linked immunosorbent assay (ELISA) for the presence of AFM 1 . AFM 1 was detected in 66 (89.2%) out of 74 samples at an average concentration of 19.0 ± 13.0 ng/l (min.-max., 9.6-80 ng/l). There was a statistically significant difference between December and June concerning AFM 1 levels (p < 0.05). Further detailed studies will be needed to determine the main sources of aflatoxins in food, to establish protection strategies against maternal and infant exposure to these mycotoxins.

Biogeographic and ecological regulation of disease: Prevalence of Sin Nombre virus in island mice is related to island area, precipitation, and predator richness

USGS Publications Warehouse

Orrock, John L.; Allan, Brian F.; Drost, Charles A.

2011-01-01

The relative roles of top-down and bottom-up forces in affecting disease prevalence in wild hosts is important for understanding disease dynamics and human disease risk. We found that the prevalence of Sin Nombre virus (SNV), the agent of a severe disease in humans (hantavirus pulmonary syndrome), in island deer mice from the eight California Channel Islands was greater with increased precipitation (a measure of productivity), greater island area, and fewer species of rodent predators. In finding a strong signal of the ecological forces affecting SNV prevalence, our work highlights the need for future work to understand the relative importance of average rodent density, population fluctuations, behavior, and specialist predators as they affect SNV prevalence. In addition to illustrating the importance of both bottom-up and top-down limitation of disease prevalence, our results suggest that predator richness may have important bearing on the risk of exposure to animal-borne diseases that affect humans.

Microplastics in bivalves cultured for human consumption.

PubMed

Van Cauwenberghe, Lisbeth; Janssen, Colin R

2014-10-01

Microplastics are present throughout the marine environment and ingestion of these plastic particles (<1 mm) has been demonstrated in a laboratory setting for a wide array of marine organisms. Here, we investigate the presence of microplastics in two species of commercially grown bivalves: Mytilus edulis and Crassostrea gigas. Microplastics were recovered from the soft tissues of both species. At time of human consumption, M. edulis contains on average 0.36 ± 0.07 particles g(-1) (wet weight), while a plastic load of 0.47 ± 0.16 particles g(-1) ww was detected in C. gigas. As a result, the annual dietary exposure for European shellfish consumers can amount to 11,000 microplastics per year. The presence of marine microplastics in seafood could pose a threat to food safety, however, due to the complexity of estimating microplastic toxicity, estimations of the potential risks for human health posed by microplastics in food stuffs is not (yet) possible. Copyright © 2014 Elsevier Ltd. All rights reserved.